/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:3;tab-width:8;coding:utf-8 -*-â
âvi: set net ft=c ts=3 sts=3 sw=3 fenc=utf-8                                :viâ
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â                                                                              â
â  stb_truetype                                                                â
â  Copyright 2017 Sean Barrett                                                 â
â                                                                              â
â  Permission is hereby granted, free of charge, to any person obtaining       â
â  a copy of this software and associated documentation files (the             â
â  "Software"), to deal in the Software without restriction, including         â
â  without limitation the rights to use, copy, modify, merge, publish,         â
â  distribute, sublicense, and/or sell copies of the Software, and to          â
â  permit persons to whom the Software is furnished to do so, subject to       â
â  the following conditions:                                                   â
â                                                                              â
â  The above copyright notice and this permission notice shall be              â
â  included in all copies or substantial portions of the Software.             â
â                                                                              â
â  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,             â
â  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF          â
â  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.      â
â  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY        â
â  CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,        â
â  TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE           â
â  SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                      â
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#include "libc/assert.h"
#include "libc/intrin/bits.h"
#include "libc/intrin/likely.h"
#include "libc/macros.internal.h"
#include "libc/math.h"
#include "libc/mem/mem.h"
#include "libc/runtime/runtime.h"
#include "libc/str/str.h"
#include "third_party/stb/stb_rect_pack.h"
#include "third_party/stb/stb_truetype.h"

asm(".ident\t\"\\n\\n\
stb_truetype (MIT License)\\n\
Copyright 2017 Sean Barrett\"");
asm(".include \"libc/disclaimer.inc\"");
/* clang-format off */

// stb_truetype.h - v1.26 - public domain
// authored from 2009-2021 by Sean Barrett / RAD Game Tools
//
// =======================================================================
//
//    NO SECURITY GUARANTEE -- DO NOT USE THIS ON UNTRUSTED FONT FILES
//
// This library does no range checking of the offsets found in the file,
// meaning an attacker can use it to read arbitrary memory.
//
// =======================================================================
//
//   This library processes TrueType files:
//        parse files
//        extract glyph metrics
//        extract glyph shapes
//        render glyphs to one-channel bitmaps with antialiasing (box filter)
//        render glyphs to one-channel SDF bitmaps (signed-distance
//        field/function)
//
//   Todo:
//        non-MS cmaps
//        crashproof on bad data
//        hinting? (no longer patented)
//        cleartype-style AA?
//        optimize: use simple memory allocator for intermediates
//        optimize: build edge-list directly from curves
//        optimize: rasterize directly from curves?
//
// ADDITIONAL CONTRIBUTORS
//
//   Mikko Mononen: compound shape support, more cmap formats
//   Tor Andersson: kerning, subpixel rendering
//   Dougall Johnson: OpenType / Type 2 font handling
//   Daniel Ribeiro Maciel: basic GPOS-based kerning
//
//   Misc other:
//       Ryan Gordon
//       Simon Glass
//       github:IntellectualKitty
//       Imanol Celaya
//       Daniel Ribeiro Maciel
//
//   Bug/warning reports/fixes:
//       "Zer" on mollyrocket       Fabian "ryg" Giesen   github:NiLuJe
//       Cass Everitt               Martins Mozeiko       github:aloucks
//       stoiko (Haemimont Games)   Cap Petschulat        github:oyvindjam
//       Brian Hook                 Omar Cornut           github:vassvik
//       Walter van Niftrik         Ryan Griege
//       David Gow                  Peter LaValle
//       David Given                Sergey Popov
//       Ivan-Assen Ivanov          Giumo X. Clanjor
//       Anthony Pesch              Higor Euripedes
//       Johan Duparc               Thomas Fields
//       Hou Qiming                 Derek Vinyard
//       Rob Loach                  Cort Stratton
//       Kenney Phillis Jr.         Brian Costabile
//       Ken Voskuil (kaesve)
//
// VERSION HISTORY
//
//   1.26 (2021-08-28) fix broken rasterizer
//   1.25 (2021-07-11) many fixes
//   1.24 (2020-02-05) fix warning
//
//   1.23 (2020-02-02) query SVG data for glyphs; query whole kerning
//       table (but only kern not GPOS) 1.22 (2019-08-11) minimize
//       missing-glyph duplication; fix kerning if both 'GPOS' and
//       'kern' are defined 1.21 (2019-02-25) fix warning 1.20
//       (2019-02-07) PackFontRange skips missing codepoints;
//       GetScaleFontVMetrics() 1.19 (2018-02-11) GPOS kerning,
//       STBTT_fmod 1.18
//
//   (2018-01-29) add missing function 1.17 (2017-07-23) make more
//       arguments const; doc fix 1.16 (2017-07-12) SDF support 1.15
//       (2017-03-03) make more arguments const 1.14 (2017-01-16)
//       num-fonts-in-TTC function 1.13
//
//   (2017-01-02) support OpenType fonts, certain Apple fonts 1.12
//       (2016-10-25) suppress warnings about casting away const with
//       -Wcast-qual 1.11
//
//   (2016-04-02) fix unused-variable warning 1.10 (2016-04-02)
//       user-defined fabs(); rare memory leak; remove duplicate typedef
//       1.09 (2016-01-16) warning fix; avoid crash on outofmem; use
//       allocation userdata properly 1.08
//
//   (2015-09-13) document stbtt_Rasterize(); fixes for vertical &
//       horizontal edges 1.07 (2015-08-01) allow PackFontRanges to
//       accept arrays of sparse codepoints; variant PackFontRanges to
//       pack and render in separate phases; fix
//       stbtt_GetFontOFfsetForIndex (never worked for non-0 input?);
//       fixed an ASSERT() bug in the new rasterizer replace ASSERT()
//       with STBTT_ASSERT() in new rasterizer
//
//   Full history can be found at the end of this file.
//
// LICENSE
//
//   See end of file for license information.
//
// USAGE
//
//   Include this file in whatever places need to refer to it. In ONE C/C++
//   file, write:
//      #define STB_TRUETYPE_IMPLEMENTATION
//   before the #include of this file. This expands out the actual
//   implementation into that C/C++ file.
//
//   To make the implementation private to the file that generates the
//   implementation,
//      #define STBTT_STATIC
//
//   Simple 3D API (don't ship this, but it's fine for tools and quick start)
//           stbtt_BakeFontBitmap()               -- bake a font to a bitmap for
//           use as texture stbtt_GetBakedQuad()                 -- compute quad
//           to draw for a given char
//
//   Improved 3D API (more shippable):
//           #include "stb_rect_pack.h"           -- optional, but you really
//           want it stbtt_PackBegin() stbtt_PackSetOversampling()          --
//           for improved quality on small fonts stbtt_PackFontRanges() -- pack
//           and renders stbtt_PackEnd() stbtt_GetPackedQuad()
//
//   "Load" a font file from a memory buffer (you have to keep the buffer
//   loaded)
//           stbtt_InitFont()
//           stbtt_GetFontOffsetForIndex()        -- indexing for TTC font
//           collections stbtt_GetNumberOfFonts()             -- number of fonts
//           for TTC font collections
//
//   Render a unicode codepoint to a bitmap
//           stbtt_GetCodepointBitmap()           -- allocates and returns a
//           bitmap stbtt_MakeCodepointBitmap()          -- renders into bitmap
//           you provide stbtt_GetCodepointBitmapBox()        -- how big the
//           bitmap must be
//
//   Character advance/positioning
//           stbtt_GetCodepointHMetrics()
//           stbtt_GetFontVMetrics()
//           stbtt_GetFontVMetricsOS2()
//           stbtt_GetCodepointKernAdvance()
//
//   Starting with version 1.06, the rasterizer was replaced with a new,
//   faster and generally-more-precise rasterizer. The new rasterizer more
//   accurately measures pixel coverage for anti-aliasing, except in the case
//   where multiple shapes overlap, in which case it overestimates the AA pixel
//   coverage. Thus, anti-aliasing of intersecting shapes may look wrong. If
//   this turns out to be a problem, you can re-enable the old rasterizer with
//        #define STBTT_RASTERIZER_VERSION 1
//   which will incur about a 15% speed hit.
//
// ADDITIONAL DOCUMENTATION
//
//   Immediately after this block comment are a series of sample programs.
//
//   After the sample programs is the "header file" section. This section
//   includes documentation for each API function.
//
//   Some important concepts to understand to use this library:
//
//      Codepoint
//         Characters are defined by unicode codepoints, e.g. 65 is
//         uppercase A, 231 is lowercase c with a cedilla, 0x7e30 is
//         the hiragana for "ma".
//
//      Glyph
//         A visual character shape (every codepoint is rendered as
//         some glyph)
//
//      Glyph index
//         A font-specific integer ID representing a glyph
//
//      Baseline
//         Glyph shapes are defined relative to a baseline, which is the
//         bottom of uppercase characters. Characters extend both above
//         and below the baseline.
//
//      Current Point
//         As you draw text to the screen, you keep track of a "current point"
//         which is the origin of each character. The current point's vertical
//         position is the baseline. Even "baked fonts" use this model.
//
//      Vertical Font Metrics
//         The vertical qualities of the font, used to vertically position
//         and space the characters. See docs for stbtt_GetFontVMetrics.
//
//      Font Size in Pixels or Points
//         The preferred interface for specifying font sizes in stb_truetype
//         is to specify how tall the font's vertical extent should be in
//         pixels. If that sounds good enough, skip the next paragraph.
//
//         Most font APIs instead use "points", which are a common typographic
//         measurement for describing font size, defined as 72 points per inch.
//         stb_truetype provides a point API for compatibility. However, true
//         "per inch" conventions don't make much sense on computer displays
//         since different monitors have different number of pixels per
//         inch. For example, Windows traditionally uses a convention that
//         there are 96 pixels per inch, thus making 'inch' measurements have
//         nothing to do with inches, and thus effectively defining a point to
//         be 1.333 pixels. Additionally, the TrueType font data provides
//         an explicit scale factor to scale a given font's glyphs to points,
//         but the author has observed that this scale factor is often wrong
//         for non-commercial fonts, thus making fonts scaled in points
//         according to the TrueType spec incoherently sized in practice.
//
// DETAILED USAGE:
//
//  Scale:
//    Select how high you want the font to be, in points or pixels.
//    Call ScaleForPixelHeight or ScaleForMappingEmToPixels to compute
//    a scale factor SF that will be used by all other functions.
//
//  Baseline:
//    You need to select a y-coordinate that is the baseline of where
//    your text will appear. Call GetFontBoundingBox to get the
//    baseline-relative bounding box for all characters. SF*-y0 will be the
//    distance in pixels that the worst-case character could extend above the
//    baseline, so if you want the top edge of characters to appear at the top
//    of the screen where y=0, then you would set the baseline to SF*-y0.
//
//  Current point:
//    Set the current point where the first character will appear. The
//    first character could extend left of the current point; this is font
//    dependent. You can either choose a current point that is the leftmost
//    point and hope, or add some padding, or check the bounding box or
//    left-side-bearing of the first character to be displayed and set
//    the current point based on that.
//
//  Displaying a character:
//    Compute the bounding box of the character. It will contain signed values
//    relative to <current_point, baseline>. I.e. if it returns x0,y0,x1,y1,
//    then the character should be displayed in the rectangle from
//    <current_point+SF*x0, baseline+SF*y0> to
//    <current_point+SF*x1,baseline+SF*y1).
//
//  Advancing for the next character:
//    Call GlyphHMetrics, and compute 'current_point += SF * advance'.
//
//
// ADVANCED USAGE
//
//   Quality:
//
//    - Use the functions with Subpixel at the end to allow your characters
//      to have subpixel positioning. Since the font is anti-aliased, not
//      hinted, this is very import for quality. (This is not possible with
//      baked fonts.)
//
//    - Kerning is now supported, and if you're supporting subpixel rendering
//      then kerning is worth using to give your text a polished look.
//
//   Performance:
//
//    - Convert Unicode codepoints to glyph indexes and operate on the glyphs;
//      if you don't do this, stb_truetype is forced to do the conversion on
//      every call.
//
//    - There are a lot of memory allocations. We should modify it to take
//      a temp buffer and allocate from the temp buffer (without freeing),
//      should help performance a lot.
//
// NOTES
//
//   The system uses the raw data found in the .ttf file without changing it
//   and without building auxiliary data structures. This is a bit inefficient
//   on little-endian systems (the data is big-endian), but assuming you're
//   caching the bitmaps or glyph shapes this shouldn't be a big deal.
//
//   It appears to be very hard to programmatically determine what font a
//   given file is in a general way. I provide an API for this, but I don't
//   recommend it.
//
//
// PERFORMANCE MEASUREMENTS FOR 1.06:
//
//                      32-bit     64-bit
//   Previous release:  8.83 s     7.68 s
//   Pool allocations:  7.72 s     6.34 s
//   Inline sort     :  6.54 s     5.65 s
//   New rasterizer  :  5.63 s     5.00 s

#define STBTT_MAX_OVERSAMPLE     8
#define STBTT_RASTERIZER_VERSION 2
#define STBTT__OVER_MASK         (STBTT_MAX_OVERSAMPLE-1)

#define STBTT_ifloor(x)           ((int)floor(x))
#define STBTT_iceil(x)            ((int)ceil(x))
#define STBTT_malloc(x,u)         ((void)(u),malloc(x))
#define STBTT_free(x,u)           ((void)(u),free(x))
#define stbtt__buf_get16(b)       stbtt__buf_get((b), 2)
#define stbtt__buf_get32(b)       stbtt__buf_get((b), 4)
#define ttBYTE(p)                 (*(uint8_t *)(p))
#define ttCHAR(p)                 (*(int8_t *)(p))
#define ttUSHORT(p)               READ16BE(p)
#define ttSHORT(p)                ((int16_t)READ16BE(p))
#define ttULONG(p)                READ32BE(p)
#define ttLONG(p)                 ((int32_t)READ32BE(p))
#define stbtt_tag(p,s)            (READ32LE(p)==READ32LE(s))
#define STBTT__CSCTX_INIT(bounds) {bounds,0, 0,0, 0,0, 0,0,0,0, NULL, 0}
#define ASSERT(x)                 ((void)(LIKELY(x) || (stbtt__assert_fail(#x, __LINE__), 0)))

typedef struct {
   float x;
   float y;
} stbtt__point;

typedef struct
{
   int bounds;
   int started;
   float first_x, first_y;
   float x, y;
   int32_t min_x, max_x, min_y, max_y;
   stbtt_vertex *pvertices;
   int num_vertices;
} stbtt__csctx;

typedef struct stbtt__hheap_chunk
{
   struct stbtt__hheap_chunk *next;
} stbtt__hheap_chunk;

typedef struct stbtt__hheap
{
   struct stbtt__hheap_chunk *head;
   void   *first_free;
   int    num_remaining_in_head_chunk;
} stbtt__hheap;

typedef struct stbtt__edge {
   float x0,y0, x1,y1;
   int invert;
} stbtt__edge;

typedef struct stbtt__active_edge
{
   struct stbtt__active_edge *next;
#if STBTT_RASTERIZER_VERSION==1
   int x,dx;
   float ey;
   int direction;
#elif STBTT_RASTERIZER_VERSION==2
   float fx,fdx,fdy;
   float direction;
   float sy;
   float ey;
#else
#error "Unrecognized value of STBTT_RASTERIZER_VERSION"
#endif
} stbtt__active_edge;

typedef char stbtt__check_size32[sizeof(int32_t)==4 ? 1 : -1];
typedef char stbtt__check_size16[sizeof(int16_t)==2 ? 1 : -1];
typedef int stbtt__test_oversample_pow2[(STBTT_MAX_OVERSAMPLE & (STBTT_MAX_OVERSAMPLE-1)) == 0 ? 1 : -1];

jmp_buf stbtt_jmpbuf;

static wontreturn void stbtt__assert_fail(const char *x, int line) {
   if (stbtt_jmpbuf[0]) {
      longjmp(stbtt_jmpbuf, line);
   } else {
      __assert_fail(x, __FILE__, line);
      abort();
   }
}

static uint8_t stbtt__buf_get8(stbtt__buf *b)
{
   if (b->cursor >= b->size)
      return 0;
   return b->data[b->cursor++];
}

static uint8_t stbtt__buf_peek8(stbtt__buf *b)
{
   if (b->cursor >= b->size)
      return 0;
   return b->data[b->cursor];
}

static void stbtt__buf_seek(stbtt__buf *b, int o)
{
   ASSERT(!(o > b->size || o < 0));
   b->cursor = (o > b->size || o < 0) ? b->size : o;
}

static void stbtt__buf_skip(stbtt__buf *b, int o)
{
   stbtt__buf_seek(b, b->cursor + o);
}

static uint32_t stbtt__buf_get(stbtt__buf *b, int n)
{
   uint32_t v = 0;
   int i;
   ASSERT(n >= 1 && n <= 4);
   for (i = 0; i < n; i++)
      v = (v << 8) | stbtt__buf_get8(b);
   return v;
}

static stbtt__buf stbtt__new_buf(const void *p, size_t size)
{
   stbtt__buf r;
   ASSERT(size < 0x40000000);
   r.data = (uint8_t*) p;
   r.size = (int) size;
   r.cursor = 0;
   return r;
}

static stbtt__buf stbtt__buf_range(const stbtt__buf *b, int o, int s)
{
   stbtt__buf r = stbtt__new_buf(NULL, 0);
   if (o < 0 || s < 0 || o > b->size || s > b->size - o) return r;
   r.data = b->data + o;
   r.size = s;
   return r;
}

static stbtt__buf stbtt__cff_get_index(stbtt__buf *b)
{
   int count, start, offsize;
   start = b->cursor;
   count = stbtt__buf_get16(b);
   if (count) {
      offsize = stbtt__buf_get8(b);
      ASSERT(offsize >= 1 && offsize <= 4);
      stbtt__buf_skip(b, offsize * count);
      stbtt__buf_skip(b, stbtt__buf_get(b, offsize) - 1);
   }
   return stbtt__buf_range(b, start, b->cursor - start);
}

static uint32_t stbtt__cff_int(stbtt__buf *b)
{
   int b0 = stbtt__buf_get8(b);
   if (b0 >= 32 && b0 <= 246)       return b0 - 139;
   else if (b0 >= 247 && b0 <= 250) return (b0 - 247)*256 + stbtt__buf_get8(b) + 108;
   else if (b0 >= 251 && b0 <= 254) return -(b0 - 251)*256 - stbtt__buf_get8(b) - 108;
   else if (b0 == 28)               return stbtt__buf_get16(b);
   else if (b0 == 29)               return stbtt__buf_get32(b);
   ASSERT(0);
   return 0;
}

static void stbtt__cff_skip_operand(stbtt__buf *b) {
   int v, b0 = stbtt__buf_peek8(b);
   ASSERT(b0 >= 28);
   if (b0 == 30) {
      stbtt__buf_skip(b, 1);
      while (b->cursor < b->size) {
         v = stbtt__buf_get8(b);
         if ((v & 0xF) == 0xF || (v >> 4) == 0xF)
            break;
      }
   } else {
      stbtt__cff_int(b);
   }
}

static stbtt__buf stbtt__dict_get(stbtt__buf *b, int key)
{
   stbtt__buf_seek(b, 0);
   while (b->cursor < b->size) {
      int start = b->cursor, end, op;
      while (stbtt__buf_peek8(b) >= 28)
         stbtt__cff_skip_operand(b);
      end = b->cursor;
      op = stbtt__buf_get8(b);
      if (op == 12)  op = stbtt__buf_get8(b) | 0x100;
      if (op == key) return stbtt__buf_range(b, start, end-start);
   }
   return stbtt__buf_range(b, 0, 0);
}

static void stbtt__dict_get_ints(stbtt__buf *b, int key, int outcount, uint32_t *out)
{
   int i;
   stbtt__buf operands = stbtt__dict_get(b, key);
   for (i = 0; i < outcount && operands.cursor < operands.size; i++)
      out[i] = stbtt__cff_int(&operands);
}

static int stbtt__cff_index_count(stbtt__buf *b)
{
   stbtt__buf_seek(b, 0);
   return stbtt__buf_get16(b);
}

static stbtt__buf stbtt__cff_index_get(stbtt__buf b, int i)
{
   int count, offsize, start, end;
   stbtt__buf_seek(&b, 0);
   count = stbtt__buf_get16(&b);
   offsize = stbtt__buf_get8(&b);
   ASSERT(i >= 0 && i < count);
   ASSERT(offsize >= 1 && offsize <= 4);
   stbtt__buf_skip(&b, i*offsize);
   start = stbtt__buf_get(&b, offsize);
   end = stbtt__buf_get(&b, offsize);
   return stbtt__buf_range(&b, 2+(count+1)*offsize+start, end - start);
}

//////////////////////////////////////////////////////////////////////////
//
// accessors to parse data from file
//

// on platforms that don't allow misaligned reads, if we want to allow
// truetype fonts that aren't padded to alignment, define ALLOW_UNALIGNED_TRUETYPE

static int stbtt__isfont(uint8_t *font)
{
   // check the version number
   if (stbtt_tag(font, "1\0\0\0"))  return 1; // TrueType 1
   if (stbtt_tag(font, "typ1"))     return 1; // TrueType with type 1 font -- we don't support this!
   if (stbtt_tag(font, "OTTO"))     return 1; // OpenType with CFF
   if (stbtt_tag(font, "\0\1\0\0")) return 1; // OpenType 1.0
   if (stbtt_tag(font, "true"))     return 1; // Apple specification for TrueType fonts
   return 0;
}

// @OPTIMIZE: binary search
static uint32_t stbtt__find_table(uint8_t *data, int fontstart, const char *tag)
{
   ASSERT(fontstart >= 0);
   int32_t num_tables = ttUSHORT(data+fontstart+4);
   uint32_t tabledir = fontstart + 12;
   int32_t i;
   for (i=0; i < num_tables; ++i) {
      uint32_t loc = tabledir + 16*i;
      if (stbtt_tag(data+loc+0, tag))
         return ttULONG(data+loc+8);
   }
   return 0;
}

static int stbtt_GetFontOffsetForIndex_internal(unsigned char *font_collection, int index)
{
   // if it's just a font, there's only one valid index
   if (stbtt__isfont(font_collection))
      return index == 0 ? 0 : -1;
   // check if it's a TTC
   if (stbtt_tag(font_collection, "ttcf")) {
      // version 1?
      if (ttULONG(font_collection+4) == 0x00010000 || ttULONG(font_collection+4) == 0x00020000) {
         int32_t n = ttLONG(font_collection+8);
         if (index >= n)
            return -1;
         return ttULONG(font_collection+12+index*4);
      }
   }
   return -1;
}

static int stbtt_GetNumberOfFonts_internal(unsigned char *font_collection)
{
   // if it's just a font, there's only one valid font
   if (stbtt__isfont(font_collection))
      return 1;
   // check if it's a TTC
   if (stbtt_tag(font_collection, "ttcf")) {
      // version 1?
      if (ttULONG(font_collection+4) == 0x00010000 || ttULONG(font_collection+4) == 0x00020000) {
         return ttLONG(font_collection+8);
      }
   }
   return 0;
}

static stbtt__buf stbtt__get_subrs(stbtt__buf cff, stbtt__buf fontdict)
{
   uint32_t subrsoff = 0, private_loc[2] = { 0, 0 };
   stbtt__buf pdict;
   stbtt__dict_get_ints(&fontdict, 18, 2, private_loc);
   if (!private_loc[1] || !private_loc[0]) return stbtt__new_buf(NULL, 0);
   pdict = stbtt__buf_range(&cff, private_loc[1], private_loc[0]);
   stbtt__dict_get_ints(&pdict, 19, 1, &subrsoff);
   if (!subrsoff) return stbtt__new_buf(NULL, 0);
   stbtt__buf_seek(&cff, private_loc[1]+subrsoff);
   return stbtt__cff_get_index(&cff);
}

// since most people won't use this, find this table the first time it's needed
static int stbtt__get_svg(stbtt_fontinfo *info)
{
   uint32_t t, offset;
   if (info->svg < 0) {
      t = stbtt__find_table(info->data, info->fontstart, "SVG ");
      if (t) {
         offset = ttULONG(info->data + t + 2);
         info->svg = t + offset;
      } else {
         info->svg = 0;
      }
   }
   return info->svg;
}

static int stbtt_InitFont_internal(stbtt_fontinfo *info, unsigned char *data, int fontstart)
{
   uint32_t cmap, t;
   int32_t i,numTables;
   info->data = data;
   info->fontstart = fontstart;
   info->cff = stbtt__new_buf(NULL, 0);
   cmap = stbtt__find_table(data, fontstart, "cmap");       // required
   info->loca = stbtt__find_table(data, fontstart, "loca"); // required
   info->head = stbtt__find_table(data, fontstart, "head"); // required
   info->glyf = stbtt__find_table(data, fontstart, "glyf"); // required
   info->hhea = stbtt__find_table(data, fontstart, "hhea"); // required
   info->hmtx = stbtt__find_table(data, fontstart, "hmtx"); // required
   info->kern = stbtt__find_table(data, fontstart, "kern"); // not required
   info->gpos = stbtt__find_table(data, fontstart, "GPOS"); // not required
   if (!cmap || !info->head || !info->hhea || !info->hmtx)
      return 0;
   if (info->glyf) {
      // required for truetype
      if (!info->loca) return 0;
   } else {
      // initialization for CFF / Type2 fonts (OTF)
      stbtt__buf b, topdict, topdictidx;
      uint32_t cstype = 2, charstrings = 0, fdarrayoff = 0, fdselectoff = 0;
      uint32_t cff;
      cff = stbtt__find_table(data, fontstart, "CFF ");
      if (!cff) return 0;
      info->fontdicts = stbtt__new_buf(NULL, 0);
      info->fdselect = stbtt__new_buf(NULL, 0);
      // @TODO this should use size from table (not 512MB)
      info->cff = stbtt__new_buf(data+cff, 512*1024*1024);
      b = info->cff;
      // read the header
      stbtt__buf_skip(&b, 2);
      stbtt__buf_seek(&b, stbtt__buf_get8(&b)); // hdrsize
      // @TODO the name INDEX could list multiple fonts,
      // but we just use the first one.
      stbtt__cff_get_index(&b);  // name INDEX
      topdictidx = stbtt__cff_get_index(&b);
      topdict = stbtt__cff_index_get(topdictidx, 0);
      stbtt__cff_get_index(&b);  // string INDEX
      info->gsubrs = stbtt__cff_get_index(&b);
      stbtt__dict_get_ints(&topdict, 17, 1, &charstrings);
      stbtt__dict_get_ints(&topdict, 0x100 | 6, 1, &cstype);
      stbtt__dict_get_ints(&topdict, 0x100 | 36, 1, &fdarrayoff);
      stbtt__dict_get_ints(&topdict, 0x100 | 37, 1, &fdselectoff);
      info->subrs = stbtt__get_subrs(b, topdict);
      // we only support Type 2 charstrings
      if (cstype != 2) return 0;
      if (charstrings == 0) return 0;
      if (fdarrayoff) {
         // looks like a CID font
         if (!fdselectoff) return 0;
         stbtt__buf_seek(&b, fdarrayoff);
         info->fontdicts = stbtt__cff_get_index(&b);
         info->fdselect = stbtt__buf_range(&b, fdselectoff, b.size-fdselectoff);
      }
      stbtt__buf_seek(&b, charstrings);
      info->charstrings = stbtt__cff_get_index(&b);
   }
   t = stbtt__find_table(data, fontstart, "maxp");
   if (t)
      info->numGlyphs = ttUSHORT(data+t+4);
   else
      info->numGlyphs = 0xffff;
   info->svg = -1;
   // find a cmap encoding table we understand *now* to avoid searching
   // later. (todo: could make this installable)
   // the same regardless of glyph.
   numTables = ttUSHORT(data + cmap + 2);
   info->index_map = 0;
   for (i=0; i < numTables; ++i) {
      uint32_t encoding_record = cmap + 4 + 8 * i;
      // find an encoding we understand:
      switch(ttUSHORT(data+encoding_record)) {
         case STBTT_PLATFORM_ID_MICROSOFT:
            switch (ttUSHORT(data+encoding_record+2)) {
               case STBTT_MS_EID_UNICODE_BMP:
               case STBTT_MS_EID_UNICODE_FULL:
                  // MS/Unicode
                  info->index_map = cmap + ttULONG(data+encoding_record+4);
                  break;
            }
            break;
        case STBTT_PLATFORM_ID_UNICODE:
            // Mac/iOS has these
            // all the encodingIDs are unicode, so we don't bother to check it
            info->index_map = cmap + ttULONG(data+encoding_record+4);
            break;
      }
   }
   if (info->index_map == 0)
      return 0;
   info->indexToLocFormat = ttUSHORT(data+info->head + 50);
   return 1;
}

// If you're going to perform multiple operations on the same character
// and you want a speed-up, call this function with the character you're
// going to process, then use glyph-based functions instead of the
// codepoint-based functions.
// Returns 0 if the character codepoint is not defined in the font.
int stbtt_FindGlyphIndex(const stbtt_fontinfo *info, int unicode_codepoint)
{
   uint8_t *data = info->data;
   uint32_t index_map = info->index_map;
   uint16_t format = ttUSHORT(data + index_map + 0);
   if (format == 0) { // apple byte encoding
      int32_t bytes = ttUSHORT(data + index_map + 2);
      if (unicode_codepoint < bytes-6)
         return ttBYTE(data + index_map + 6 + unicode_codepoint);
      return 0;
   } else if (format == 6) {
      uint32_t first = ttUSHORT(data + index_map + 6);
      uint32_t count = ttUSHORT(data + index_map + 8);
      if ((uint32_t) unicode_codepoint >= first && (uint32_t) unicode_codepoint < first+count)
         return ttUSHORT(data + index_map + 10 + (unicode_codepoint - first)*2);
      return 0;
   } else if (format == 2) {
      ASSERT(0); // @TODO: high-byte mapping for japanese/chinese/korean
      return 0;
   } else if (format == 4) { // standard mapping for windows fonts: binary search collection of ranges
      uint16_t segcount = ttUSHORT(data+index_map+6) >> 1;
      uint16_t searchRange = ttUSHORT(data+index_map+8) >> 1;
      uint16_t entrySelector = ttUSHORT(data+index_map+10);
      uint16_t rangeShift = ttUSHORT(data+index_map+12) >> 1;
      // do a binary search of the segments
      uint32_t endCount = index_map + 14;
      uint32_t search = endCount;
      if (unicode_codepoint > 0xffff)
         return 0;
      // they lie from endCount .. endCount + segCount
      // but searchRange is the nearest power of two, so...
      if (unicode_codepoint >= ttUSHORT(data + search + rangeShift*2))
         search += rangeShift*2;
      // now decrement to bias correctly to find smallest
      search -= 2;
      while (entrySelector) {
         uint16_t end;
         searchRange >>= 1;
         end = ttUSHORT(data + search + searchRange*2);
         if (unicode_codepoint > end)
            search += searchRange*2;
         --entrySelector;
      }
      search += 2;
      {
         uint16_t offset, start, last;
         uint16_t item = (uint16_t) ((search - endCount) >> 1);
         start = ttUSHORT(data + index_map + 14 + segcount*2 + 2 + 2*item);
         last = ttUSHORT(data + endCount + 2*item);
         if (unicode_codepoint < start || unicode_codepoint > last)
            return 0;
         offset = ttUSHORT(data + index_map + 14 + segcount*6 + 2 + 2*item);
         if (offset == 0)
            return (uint16_t) (unicode_codepoint + ttSHORT(data + index_map + 14 + segcount*4 + 2 + 2*item));
         return ttUSHORT(data + offset + (unicode_codepoint-start)*2 + index_map + 14 + segcount*6 + 2 + 2*item);
      }
   } else if (format == 12 || format == 13) {
      uint32_t ngroups = ttULONG(data+index_map+12);
      int32_t low,high;
      low = 0; high = (int32_t)ngroups;
      // Binary search the right group.
      while (low < high) {
         int32_t mid = low + ((high-low) >> 1); // rounds down, so low <= mid < high
         uint32_t start_char = ttULONG(data+index_map+16+mid*12);
         uint32_t end_char = ttULONG(data+index_map+16+mid*12+4);
         if ((uint32_t) unicode_codepoint < start_char)
            high = mid;
         else if ((uint32_t) unicode_codepoint > end_char)
            low = mid+1;
         else {
            uint32_t start_glyph = ttULONG(data+index_map+16+mid*12+8);
            if (format == 12)
               return start_glyph + unicode_codepoint-start_char;
            else // format == 13
               return start_glyph;
         }
      }
      return 0; // not found
   }
   // @TODO
   ASSERT(0);
   return 0;
}

int stbtt_GetCodepointShape(const stbtt_fontinfo *info, int unicode_codepoint, stbtt_vertex **vertices)
{
   return stbtt_GetGlyphShape(info, stbtt_FindGlyphIndex(info, unicode_codepoint), vertices);
}

static void stbtt_setvertex(stbtt_vertex *v, uint8_t type, int32_t x, int32_t y, int32_t cx, int32_t cy)
{
   v->type = type;
   v->x = (int16_t) x;
   v->y = (int16_t) y;
   v->cx = (int16_t) cx;
   v->cy = (int16_t) cy;
}

static int stbtt__GetGlyfOffset(const stbtt_fontinfo *info, int glyph_index)
{
   int g1,g2;
   ASSERT(!info->cff.size);
   if (glyph_index >= info->numGlyphs) return -1; // glyph index out of range
   if (info->indexToLocFormat >= 2)    return -1; // unknown index->glyph map format
   if (info->indexToLocFormat == 0) {
      g1 = info->glyf + ttUSHORT(info->data + info->loca + glyph_index * 2) * 2;
      g2 = info->glyf + ttUSHORT(info->data + info->loca + glyph_index * 2 + 2) * 2;
   } else {
      g1 = info->glyf + ttULONG (info->data + info->loca + glyph_index * 4);
      g2 = info->glyf + ttULONG (info->data + info->loca + glyph_index * 4 + 4);
   }
   return g1==g2 ? -1 : g1; // if length is 0, return -1
}

static int stbtt__GetGlyphInfoT2(const stbtt_fontinfo *info, int glyph_index, int *x0, int *y0, int *x1, int *y1);

int stbtt_GetGlyphBox(const stbtt_fontinfo *info, int glyph_index, int *x0, int *y0, int *x1, int *y1)
{
   if (info->cff.size) {
      stbtt__GetGlyphInfoT2(info, glyph_index, x0, y0, x1, y1);
   } else {
      int g = stbtt__GetGlyfOffset(info, glyph_index);
      if (g < 0) return 0;
      if (x0) *x0 = ttSHORT(info->data + g + 2);
      if (y0) *y0 = ttSHORT(info->data + g + 4);
      if (x1) *x1 = ttSHORT(info->data + g + 6);
      if (y1) *y1 = ttSHORT(info->data + g + 8);
   }
   return 1;
}

// Gets the bounding box of the visible part of the glyph, in unscaled coordinates
int stbtt_GetCodepointBox(const stbtt_fontinfo *info, int codepoint, int *x0, int *y0, int *x1, int *y1)
{
   return stbtt_GetGlyphBox(info, stbtt_FindGlyphIndex(info,codepoint), x0,y0,x1,y1);
}

// returns non-zero if nothing is drawn for this glyph
int stbtt_IsGlyphEmpty(const stbtt_fontinfo *info, int glyph_index)
{
   int16_t numberOfContours;
   int g;
   if (info->cff.size)
      return stbtt__GetGlyphInfoT2(info, glyph_index, NULL, NULL, NULL, NULL) == 0;
   g = stbtt__GetGlyfOffset(info, glyph_index);
   if (g < 0) return 1;
   numberOfContours = ttSHORT(info->data + g);
   return numberOfContours == 0;
}

static int stbtt__close_shape(stbtt_vertex *vertices, int num_vertices, int was_off, int start_off,
                              int32_t sx, int32_t sy, int32_t scx, int32_t scy, int32_t cx, int32_t cy)
{
   if (start_off) {
      if (was_off)
         stbtt_setvertex(&vertices[num_vertices++], STBTT_vcurve, (cx+scx)>>1, (cy+scy)>>1, cx,cy);
      stbtt_setvertex(&vertices[num_vertices++], STBTT_vcurve, sx,sy,scx,scy);
   } else {
      if (was_off)
         stbtt_setvertex(&vertices[num_vertices++], STBTT_vcurve,sx,sy,cx,cy);
      else
         stbtt_setvertex(&vertices[num_vertices++], STBTT_vline,sx,sy,0,0);
   }
   return num_vertices;
}

static int stbtt__GetGlyphShapeTT(const stbtt_fontinfo *info, int glyph_index,
                                  stbtt_vertex **pvertices)
{
   int16_t numberOfContours;
   uint8_t *endPtsOfContours;
   uint8_t *data = info->data;
   stbtt_vertex *vertices=0;
   int num_vertices=0;
   int g = stbtt__GetGlyfOffset(info, glyph_index);
   *pvertices = NULL;
   if (g < 0) return 0;
   numberOfContours = ttSHORT(data + g);
   if (numberOfContours > 0) {
      uint8_t flags=0,flagcount;
      int32_t ins, i,j=0,m,n, next_move, was_off=0, off, start_off=0;
      int32_t x,y,cx,cy,sx,sy, scx,scy;
      uint8_t *points;
      endPtsOfContours = (data + g + 10);
      ins = ttUSHORT(data + g + 10 + numberOfContours * 2);
      points = data + g + 10 + numberOfContours * 2 + 2 + ins;
      n = 1+ttUSHORT(endPtsOfContours + numberOfContours*2-2);
      m = n + 2*numberOfContours;  // a loose bound on how many vertices we might need
      vertices = STBTT_malloc(m * sizeof(vertices[0]), info->userdata);
      if (vertices == 0)
         return 0;
      next_move = 0;
      flagcount=0;
      // in first pass, we load uninterpreted data into the allocated array
      // above, shifted to the end of the array so we won't overwrite it when
      // we create our final data starting from the front
      off = m - n; // starting offset for uninterpreted data, regardless of how m ends up being calculated
      // first load flags
      for (i=0; i < n; ++i) {
         if (flagcount == 0) {
            flags = *points++;
            if (flags & 8)
               flagcount = *points++;
         } else
            --flagcount;
         vertices[off+i].type = flags;
      }
      // now load x coordinates
      x=0;
      for (i=0; i < n; ++i) {
         flags = vertices[off+i].type;
         if (flags & 2) {
            int16_t dx = *points++;
            x += (flags & 16) ? dx : -dx; // ???
         } else {
            if (!(flags & 16)) {
               x = x + (int16_t) (points[0]*256 + points[1]);
               points += 2;
            }
         }
         vertices[off+i].x = (int16_t) x;
      }
      // now load y coordinates
      y=0;
      for (i=0; i < n; ++i) {
         flags = vertices[off+i].type;
         if (flags & 4) {
            int16_t dy = *points++;
            y += (flags & 32) ? dy : -dy; // ???
         } else {
            if (!(flags & 32)) {
               y = y + (int16_t) (points[0]*256 + points[1]);
               points += 2;
            }
         }
         vertices[off+i].y = (int16_t) y;
      }
      // now convert them to our format
      num_vertices=0;
      sx = sy = cx = cy = scx = scy = 0;
      for (i=0; i < n; ++i) {
         flags = vertices[off+i].type;
         x     = (int16_t) vertices[off+i].x;
         y     = (int16_t) vertices[off+i].y;
         if (next_move == i) {
            if (i != 0)
               num_vertices = stbtt__close_shape(vertices, num_vertices, was_off, start_off, sx,sy,scx,scy,cx,cy);
            // now start the new one
            start_off = !(flags & 1);
            if (start_off) {
               // if we start off with an off-curve point, then when we need to find a point on the curve
               // where we can start, and we need to save some state for when we wraparound.
               scx = x;
               scy = y;
               if (!(vertices[off+i+1].type & 1)) {
                  // next point is also a curve point, so interpolate an on-point curve
                  sx = (x + (int32_t) vertices[off+i+1].x) >> 1;
                  sy = (y + (int32_t) vertices[off+i+1].y) >> 1;
               } else {
                  // otherwise just use the next point as our start point
                  sx = (int32_t) vertices[off+i+1].x;
                  sy = (int32_t) vertices[off+i+1].y;
                  ++i; // we're using point i+1 as the starting point, so skip it
               }
            } else {
               sx = x;
               sy = y;
            }
            stbtt_setvertex(&vertices[num_vertices++], STBTT_vmove,sx,sy,0,0);
            was_off = 0;
            next_move = 1 + ttUSHORT(endPtsOfContours+j*2);
            ++j;
         } else {
            if (!(flags & 1)) { // if it's a curve
               if (was_off) // two off-curve control points in a row means interpolate an on-curve midpoint
                  stbtt_setvertex(&vertices[num_vertices++], STBTT_vcurve, (cx+x)>>1, (cy+y)>>1, cx, cy);
               cx = x;
               cy = y;
               was_off = 1;
            } else {
               if (was_off)
                  stbtt_setvertex(&vertices[num_vertices++], STBTT_vcurve, x,y, cx, cy);
               else
                  stbtt_setvertex(&vertices[num_vertices++], STBTT_vline, x,y,0,0);
               was_off = 0;
            }
         }
      }
      num_vertices = stbtt__close_shape(vertices, num_vertices, was_off, start_off, sx,sy,scx,scy,cx,cy);
   } else if (numberOfContours < 0) {
      // Compound shapes.
      int more = 1;
      uint8_t *comp = data + g + 10;
      num_vertices = 0;
      vertices = 0;
      while (more) {
         uint16_t flags, gidx;
         int comp_num_verts = 0, i;
         stbtt_vertex *comp_verts = 0, *tmp = 0;
         float mtx[6] = {1,0,0,1,0,0}, m, n;
         flags = ttSHORT(comp); comp+=2;
         gidx = ttSHORT(comp); comp+=2;
         if (flags & 2) { // XY values
            if (flags & 1) { // shorts
               mtx[4] = ttSHORT(comp); comp+=2;
               mtx[5] = ttSHORT(comp); comp+=2;
            } else {
               mtx[4] = ttCHAR(comp); comp+=1;
               mtx[5] = ttCHAR(comp); comp+=1;
            }
         }
         else {
            // @TODO handle matching point
            ASSERT(0);
         }
         if (flags & (1<<3)) { // WE_HAVE_A_SCALE
            mtx[0] = mtx[3] = ttSHORT(comp)/16384.0f; comp+=2;
            mtx[1] = mtx[2] = 0;
         } else if (flags & (1<<6)) { // WE_HAVE_AN_X_AND_YSCALE
            mtx[0] = ttSHORT(comp)/16384.0f; comp+=2;
            mtx[1] = mtx[2] = 0;
            mtx[3] = ttSHORT(comp)/16384.0f; comp+=2;
         } else if (flags & (1<<7)) { // WE_HAVE_A_TWO_BY_TWO
            mtx[0] = ttSHORT(comp)/16384.0f; comp+=2;
            mtx[1] = ttSHORT(comp)/16384.0f; comp+=2;
            mtx[2] = ttSHORT(comp)/16384.0f; comp+=2;
            mtx[3] = ttSHORT(comp)/16384.0f; comp+=2;
         }
         // Find transformation scales.
         m = (float) sqrt(mtx[0]*mtx[0] + mtx[1]*mtx[1]);
         n = (float) sqrt(mtx[2]*mtx[2] + mtx[3]*mtx[3]);
         // Get indexed glyph.
         comp_num_verts = stbtt_GetGlyphShape(info, gidx, &comp_verts);
         if (comp_num_verts > 0) {
            // Transform vertices.
            for (i = 0; i < comp_num_verts; ++i) {
               stbtt_vertex* v = &comp_verts[i];
               stbtt_vertex_type x,y;
               x=v->x; y=v->y;
               v->x = (stbtt_vertex_type)(m * (mtx[0]*x + mtx[2]*y + mtx[4]));
               v->y = (stbtt_vertex_type)(n * (mtx[1]*x + mtx[3]*y + mtx[5]));
               x=v->cx; y=v->cy;
               v->cx = (stbtt_vertex_type)(m * (mtx[0]*x + mtx[2]*y + mtx[4]));
               v->cy = (stbtt_vertex_type)(n * (mtx[1]*x + mtx[3]*y + mtx[5]));
            }
            // Append vertices.
            tmp = STBTT_malloc((num_vertices+comp_num_verts)*sizeof(stbtt_vertex), info->userdata);
            if (!tmp) {
               if (vertices) STBTT_free(vertices, info->userdata);
               if (comp_verts) STBTT_free(comp_verts, info->userdata);
               return 0;
            }
            if (num_vertices > 0 && vertices) memcpy(tmp, vertices, num_vertices*sizeof(stbtt_vertex));
            memcpy(tmp+num_vertices, comp_verts, comp_num_verts*sizeof(stbtt_vertex));
            if (vertices) STBTT_free(vertices, info->userdata);
            vertices = tmp;
            STBTT_free(comp_verts, info->userdata);
            num_vertices += comp_num_verts;
         }
         // More components ?
         more = flags & (1<<5);
      }
   } else {
      // numberOfCounters == 0, do nothing
   }
   *pvertices = vertices;
   return num_vertices;
}

static void stbtt__track_vertex(stbtt__csctx *c, int32_t x, int32_t y)
{
   if (x > c->max_x || !c->started) c->max_x = x;
   if (y > c->max_y || !c->started) c->max_y = y;
   if (x < c->min_x || !c->started) c->min_x = x;
   if (y < c->min_y || !c->started) c->min_y = y;
   c->started = 1;
}

static void stbtt__csctx_v(stbtt__csctx *c, uint8_t type, int32_t x, int32_t y,
                           int32_t cx, int32_t cy, int32_t cx1, int32_t cy1)
{
   if (c->bounds) {
      stbtt__track_vertex(c, x, y);
      if (type == STBTT_vcubic) {
         stbtt__track_vertex(c, cx, cy);
         stbtt__track_vertex(c, cx1, cy1);
      }
   } else {
      stbtt_setvertex(&c->pvertices[c->num_vertices], type, x, y, cx, cy);
      c->pvertices[c->num_vertices].cx1 = (int16_t) cx1;
      c->pvertices[c->num_vertices].cy1 = (int16_t) cy1;
   }
   c->num_vertices++;
}

static void stbtt__csctx_close_shape(stbtt__csctx *ctx)
{
   if (ctx->first_x != ctx->x || ctx->first_y != ctx->y)
      stbtt__csctx_v(ctx, STBTT_vline, (int)ctx->first_x, (int)ctx->first_y, 0, 0, 0, 0);
}

static void stbtt__csctx_rmove_to(stbtt__csctx *ctx, float dx, float dy)
{
   stbtt__csctx_close_shape(ctx);
   ctx->first_x = ctx->x = ctx->x + dx;
   ctx->first_y = ctx->y = ctx->y + dy;
   stbtt__csctx_v(ctx, STBTT_vmove, (int)ctx->x, (int)ctx->y, 0, 0, 0, 0);
}

static void stbtt__csctx_rline_to(stbtt__csctx *ctx, float dx, float dy)
{
   ctx->x += dx;
   ctx->y += dy;
   stbtt__csctx_v(ctx, STBTT_vline, (int)ctx->x, (int)ctx->y, 0, 0, 0, 0);
}

static void stbtt__csctx_rccurve_to(stbtt__csctx *ctx, float dx1, float dy1,
                                    float dx2, float dy2, float dx3, float dy3)
{
   float cx1 = ctx->x + dx1;
   float cy1 = ctx->y + dy1;
   float cx2 = cx1 + dx2;
   float cy2 = cy1 + dy2;
   ctx->x = cx2 + dx3;
   ctx->y = cy2 + dy3;
   stbtt__csctx_v(ctx, STBTT_vcubic, (int)ctx->x, (int)ctx->y, (int)cx1, (int)cy1, (int)cx2, (int)cy2);
}

static stbtt__buf stbtt__get_subr(stbtt__buf idx, int n)
{
   int count = stbtt__cff_index_count(&idx);
   int bias = 107;
   if (count >= 33900)
      bias = 32768;
   else if (count >= 1240)
      bias = 1131;
   n += bias;
   if (n < 0 || n >= count)
      return stbtt__new_buf(NULL, 0);
   return stbtt__cff_index_get(idx, n);
}

static stbtt__buf stbtt__cid_get_glyph_subrs(const stbtt_fontinfo *info, int glyph_index)
{
   stbtt__buf fdselect = info->fdselect;
   int nranges, start, end, v, fmt, fdselector = -1, i;
   stbtt__buf_seek(&fdselect, 0);
   fmt = stbtt__buf_get8(&fdselect);
   if (fmt == 0) {
      // untested
      stbtt__buf_skip(&fdselect, glyph_index);
      fdselector = stbtt__buf_get8(&fdselect);
   } else if (fmt == 3) {
      nranges = stbtt__buf_get16(&fdselect);
      start = stbtt__buf_get16(&fdselect);
      for (i = 0; i < nranges; i++) {
         v = stbtt__buf_get8(&fdselect);
         end = stbtt__buf_get16(&fdselect);
         if (glyph_index >= start && glyph_index < end) {
            fdselector = v;
            break;
         }
         start = end;
      }
   }
   if (fdselector == -1) stbtt__new_buf(NULL, 0);
   return stbtt__get_subrs(info->cff, stbtt__cff_index_get(info->fontdicts, fdselector));
}

static int stbtt__run_charstring(const stbtt_fontinfo *info, int glyph_index, stbtt__csctx *c)
{
   int in_header = 1, maskbits = 0, subr_stack_height = 0, sp = 0, v, i, b0;
   int has_subrs = 0, clear_stack;
   float s[48];
   stbtt__buf subr_stack[10], subrs = info->subrs, b;
   float f;
#define STBTT__CSERR(s) (0)
   // this currently ignores the initial width value, which isn't needed if we have hmtx
   b = stbtt__cff_index_get(info->charstrings, glyph_index);
   while (b.cursor < b.size) {
      i = 0;
      clear_stack = 1;
      b0 = stbtt__buf_get8(&b);
      switch (b0) {
      // @TODO implement hinting
      case 0x13: // hintmask
      case 0x14: // cntrmask
         if (in_header)
            maskbits += (sp / 2); // implicit "vstem"
         in_header = 0;
         stbtt__buf_skip(&b, (maskbits + 7) / 8);
         break;
      case 0x01: // hstem
      case 0x03: // vstem
      case 0x12: // hstemhm
      case 0x17: // vstemhm
         maskbits += (sp / 2);
         break;
      case 0x15: // rmoveto
         in_header = 0;
         if (sp < 2) return STBTT__CSERR("rmoveto stack");
         stbtt__csctx_rmove_to(c, s[sp-2], s[sp-1]);
         break;
      case 0x04: // vmoveto
         in_header = 0;
         if (sp < 1) return STBTT__CSERR("vmoveto stack");
         stbtt__csctx_rmove_to(c, 0, s[sp-1]);
         break;
      case 0x16: // hmoveto
         in_header = 0;
         if (sp < 1) return STBTT__CSERR("hmoveto stack");
         stbtt__csctx_rmove_to(c, s[sp-1], 0);
         break;
      case 0x05: // rlineto
         if (sp < 2) return STBTT__CSERR("rlineto stack");
         for (; i + 1 < sp; i += 2)
            stbtt__csctx_rline_to(c, s[i], s[i+1]);
         break;
      // hlineto/vlineto and vhcurveto/hvcurveto alternate horizontal and vertical
      // starting from a different place.
      case 0x07: // vlineto
         if (sp < 1) return STBTT__CSERR("vlineto stack");
         goto vlineto;
      case 0x06: // hlineto
         if (sp < 1) return STBTT__CSERR("hlineto stack");
         for (;;) {
            if (i >= sp) break;
            stbtt__csctx_rline_to(c, s[i], 0);
            i++;
      vlineto:
            if (i >= sp) break;
            stbtt__csctx_rline_to(c, 0, s[i]);
            i++;
         }
         break;
      case 0x1F: // hvcurveto
         if (sp < 4) return STBTT__CSERR("hvcurveto stack");
         goto hvcurveto;
      case 0x1E: // vhcurveto
         if (sp < 4) return STBTT__CSERR("vhcurveto stack");
         for (;;) {
            if (i + 3 >= sp) break;
            stbtt__csctx_rccurve_to(c, 0, s[i], s[i+1], s[i+2], s[i+3], (sp - i == 5) ? s[i + 4] : 0.0f);
            i += 4;
      hvcurveto:
            if (i + 3 >= sp) break;
            stbtt__csctx_rccurve_to(c, s[i], 0, s[i+1], s[i+2], (sp - i == 5) ? s[i+4] : 0.0f, s[i+3]);
            i += 4;
         }
         break;
      case 0x08: // rrcurveto
         if (sp < 6) return STBTT__CSERR("rcurveline stack");
         for (; i + 5 < sp; i += 6)
            stbtt__csctx_rccurve_to(c, s[i], s[i+1], s[i+2], s[i+3], s[i+4], s[i+5]);
         break;
      case 0x18: // rcurveline
         if (sp < 8) return STBTT__CSERR("rcurveline stack");
         for (; i + 5 < sp - 2; i += 6)
            stbtt__csctx_rccurve_to(c, s[i], s[i+1], s[i+2], s[i+3], s[i+4], s[i+5]);
         if (i + 1 >= sp) return STBTT__CSERR("rcurveline stack");
         stbtt__csctx_rline_to(c, s[i], s[i+1]);
         break;
      case 0x19: // rlinecurve
         if (sp < 8) return STBTT__CSERR("rlinecurve stack");
         for (; i + 1 < sp - 6; i += 2)
            stbtt__csctx_rline_to(c, s[i], s[i+1]);
         if (i + 5 >= sp) return STBTT__CSERR("rlinecurve stack");
         stbtt__csctx_rccurve_to(c, s[i], s[i+1], s[i+2], s[i+3], s[i+4], s[i+5]);
         break;
      case 0x1A: // vvcurveto
      case 0x1B: // hhcurveto
         if (sp < 4) return STBTT__CSERR("(vv|hh)curveto stack");
         f = 0.0;
         if (sp & 1) { f = s[i]; i++; }
         for (; i + 3 < sp; i += 4) {
            if (b0 == 0x1B)
               stbtt__csctx_rccurve_to(c, s[i], f, s[i+1], s[i+2], s[i+3], 0.0);
            else
               stbtt__csctx_rccurve_to(c, f, s[i], s[i+1], s[i+2], 0.0, s[i+3]);
            f = 0.0;
         }
         break;
      case 0x0A: // callsubr
         if (!has_subrs) {
            if (info->fdselect.size)
               subrs = stbtt__cid_get_glyph_subrs(info, glyph_index);
            has_subrs = 1;
         }
         // FALLTHROUGH
      case 0x1D: // callgsubr
         if (sp < 1) return STBTT__CSERR("call(g|)subr stack");
         v = (int) s[--sp];
         if (subr_stack_height >= 10) return STBTT__CSERR("recursion limit");
         subr_stack[subr_stack_height++] = b;
         b = stbtt__get_subr(b0 == 0x0A ? subrs : info->gsubrs, v);
         if (b.size == 0) return STBTT__CSERR("subr not found");
         b.cursor = 0;
         clear_stack = 0;
         break;
      case 0x0B: // return
         if (subr_stack_height <= 0) return STBTT__CSERR("return outside subr");
         b = subr_stack[--subr_stack_height];
         clear_stack = 0;
         break;
      case 0x0E: // endchar
         stbtt__csctx_close_shape(c);
         return 1;
      case 0x0C: { // two-byte escape
         float dx1, dx2, dx3, dx4, dx5, dx6, dy1, dy2, dy3, dy4, dy5, dy6;
         float dx, dy;
         int b1 = stbtt__buf_get8(&b);
         switch (b1) {
         // @TODO These "flex" implementations ignore the flex-depth and resolution,
         // and always draw beziers.
         case 0x22: // hflex
            if (sp < 7) return STBTT__CSERR("hflex stack");
            dx1 = s[0];
            dx2 = s[1];
            dy2 = s[2];
            dx3 = s[3];
            dx4 = s[4];
            dx5 = s[5];
            dx6 = s[6];
            stbtt__csctx_rccurve_to(c, dx1, 0, dx2, dy2, dx3, 0);
            stbtt__csctx_rccurve_to(c, dx4, 0, dx5, -dy2, dx6, 0);
            break;
         case 0x23: // flex
            if (sp < 13) return STBTT__CSERR("flex stack");
            dx1 = s[0];
            dy1 = s[1];
            dx2 = s[2];
            dy2 = s[3];
            dx3 = s[4];
            dy3 = s[5];
            dx4 = s[6];
            dy4 = s[7];
            dx5 = s[8];
            dy5 = s[9];
            dx6 = s[10];
            dy6 = s[11];
            //fd is s[12]
            stbtt__csctx_rccurve_to(c, dx1, dy1, dx2, dy2, dx3, dy3);
            stbtt__csctx_rccurve_to(c, dx4, dy4, dx5, dy5, dx6, dy6);
            break;
         case 0x24: // hflex1
            if (sp < 9) return STBTT__CSERR("hflex1 stack");
            dx1 = s[0];
            dy1 = s[1];
            dx2 = s[2];
            dy2 = s[3];
            dx3 = s[4];
            dx4 = s[5];
            dx5 = s[6];
            dy5 = s[7];
            dx6 = s[8];
            stbtt__csctx_rccurve_to(c, dx1, dy1, dx2, dy2, dx3, 0);
            stbtt__csctx_rccurve_to(c, dx4, 0, dx5, dy5, dx6, -(dy1+dy2+dy5));
            break;
         case 0x25: // flex1
            if (sp < 11) return STBTT__CSERR("flex1 stack");
            dx1 = s[0];
            dy1 = s[1];
            dx2 = s[2];
            dy2 = s[3];
            dx3 = s[4];
            dy3 = s[5];
            dx4 = s[6];
            dy4 = s[7];
            dx5 = s[8];
            dy5 = s[9];
            dx6 = dy6 = s[10];
            dx = dx1+dx2+dx3+dx4+dx5;
            dy = dy1+dy2+dy3+dy4+dy5;
            if (fabs(dx) > fabs(dy))
               dy6 = -dy;
            else
               dx6 = -dx;
            stbtt__csctx_rccurve_to(c, dx1, dy1, dx2, dy2, dx3, dy3);
            stbtt__csctx_rccurve_to(c, dx4, dy4, dx5, dy5, dx6, dy6);
            break;
         default:
            return STBTT__CSERR("unimplemented");
         }
      } break;
      default:
         if (b0 != 255 && b0 != 28 && b0 < 32)
            return STBTT__CSERR("reserved operator");
         // push immediate
         if (b0 == 255) {
            f = (float)(int32_t)stbtt__buf_get32(&b) / 0x10000;
         } else {
            stbtt__buf_skip(&b, -1);
            f = (float)(int16_t)stbtt__cff_int(&b);
         }
         if (sp >= 48) return STBTT__CSERR("push stack overflow");
         s[sp++] = f;
         clear_stack = 0;
         break;
      }
      if (clear_stack) sp = 0;
   }
   return STBTT__CSERR("no endchar");
#undef STBTT__CSERR
}

static int stbtt__GetGlyphShapeT2(const stbtt_fontinfo *info, int glyph_index, stbtt_vertex **pvertices)
{
   // runs the charstring twice, once to count and once to output (to avoid realloc)
   stbtt__csctx count_ctx = STBTT__CSCTX_INIT(1);
   stbtt__csctx output_ctx = STBTT__CSCTX_INIT(0);
   if (stbtt__run_charstring(info, glyph_index, &count_ctx)) {
      *pvertices = STBTT_malloc(count_ctx.num_vertices*sizeof(stbtt_vertex), info->userdata);
      output_ctx.pvertices = *pvertices;
      if (stbtt__run_charstring(info, glyph_index, &output_ctx)) {
         ASSERT(output_ctx.num_vertices == count_ctx.num_vertices);
         return output_ctx.num_vertices;
      }
   }
   *pvertices = NULL;
   return 0;
}

static int stbtt__GetGlyphInfoT2(const stbtt_fontinfo *info, int glyph_index, int *x0, int *y0, int *x1, int *y1)
{
   stbtt__csctx c = STBTT__CSCTX_INIT(1);
   int r = stbtt__run_charstring(info, glyph_index, &c);
   if (x0)  *x0 = r ? c.min_x : 0;
   if (y0)  *y0 = r ? c.min_y : 0;
   if (x1)  *x1 = r ? c.max_x : 0;
   if (y1)  *y1 = r ? c.max_y : 0;
   return r ? c.num_vertices : 0;
}

// returns # of vertices and fills *vertices with the pointer to them
//   these are expressed in "unscaled" coordinates
//
// The shape is a series of contours. Each one starts with
// a STBTT_moveto, then consists of a series of mixed
// STBTT_lineto and STBTT_curveto segments. A lineto
// draws a line from previous endpoint to its x,y; a curveto
// draws a quadratic bezier from previous endpoint to
// its x,y, using cx,cy as the bezier control point.
int stbtt_GetGlyphShape(const stbtt_fontinfo *info, int glyph_index, stbtt_vertex **pvertices)
{
   if (!info->cff.size)
      return stbtt__GetGlyphShapeTT(info, glyph_index, pvertices);
   else
      return stbtt__GetGlyphShapeT2(info, glyph_index, pvertices);
}

void stbtt_GetGlyphHMetrics(const stbtt_fontinfo *info, int glyph_index, int *advanceWidth, int *leftSideBearing)
{
   uint16_t numOfLongHorMetrics = ttUSHORT(info->data+info->hhea + 34);
   if (glyph_index < numOfLongHorMetrics) {
      if (advanceWidth)     *advanceWidth    = ttSHORT(info->data + info->hmtx + 4*glyph_index);
      if (leftSideBearing)  *leftSideBearing = ttSHORT(info->data + info->hmtx + 4*glyph_index + 2);
   } else {
      if (advanceWidth)     *advanceWidth    = ttSHORT(info->data + info->hmtx + 4*(numOfLongHorMetrics-1));
      if (leftSideBearing)  *leftSideBearing = ttSHORT(info->data + info->hmtx + 4*numOfLongHorMetrics + 2*(glyph_index - numOfLongHorMetrics));
   }
}

// Retrieves a complete list of all of the kerning pairs provided by the font
// stbtt_GetKerningTable never writes more than table_length entries and returns how many entries it did write.
// The table will be sorted by (a.glyph1 == b.glyph1)?(a.glyph2 < b.glyph2):(a.glyph1 < b.glyph1)
int stbtt_GetKerningTableLength(const stbtt_fontinfo *info)
{
   uint8_t *data = info->data + info->kern;
   // we only look at the first table. it must be 'horizontal' and format 0.
   if (!info->kern)
      return 0;
   if (ttUSHORT(data+2) < 1) // number of tables, need at least 1
      return 0;
   if (ttUSHORT(data+8) != 1) // horizontal flag must be set in format
      return 0;
   return ttUSHORT(data+10);
}

int stbtt_GetKerningTable(const stbtt_fontinfo *info, stbtt_kerningentry* table, int table_length)
{
   uint8_t *data = info->data + info->kern;
   int k, length;
   // we only look at the first table. it must be 'horizontal' and format 0.
   if (!info->kern)
      return 0;
   if (ttUSHORT(data+2) < 1) // number of tables, need at least 1
      return 0;
   if (ttUSHORT(data+8) != 1) // horizontal flag must be set in format
      return 0;
   length = ttUSHORT(data+10);
   if (table_length < length)
      length = table_length;
   for (k = 0; k < length; k++)
   {
      table[k].glyph1 = ttUSHORT(data+18+(k*6));
      table[k].glyph2 = ttUSHORT(data+20+(k*6));
      table[k].advance = ttSHORT(data+22+(k*6));
   }
   return length;
}

static int stbtt__GetGlyphKernInfoAdvance(const stbtt_fontinfo *info, int glyph1, int glyph2)
{
   uint8_t *data = info->data + info->kern;
   uint32_t needle, straw;
   int l, r, m;
   // we only look at the first table. it must be 'horizontal' and format 0.
   if (!info->kern)
      return 0;
   if (ttUSHORT(data+2) < 1) // number of tables, need at least 1
      return 0;
   if (ttUSHORT(data+8) != 1) // horizontal flag must be set in format
      return 0;
   l = 0;
   r = ttUSHORT(data+10) - 1;
   needle = glyph1 << 16 | glyph2;
   while (l <= r) {
      m = (l + r) >> 1;
      straw = ttULONG(data+18+(m*6)); // note: unaligned read
      if (needle < straw)
         r = m - 1;
      else if (needle > straw)
         l = m + 1;
      else
         return ttSHORT(data+22+(m*6));
   }
   return 0;
}

static int32_t stbtt__GetCoverageIndex(uint8_t *coverageTable, int glyph)
{
   uint16_t coverageFormat = ttUSHORT(coverageTable);
   switch (coverageFormat) {
      case 1: {
         uint16_t glyphCount = ttUSHORT(coverageTable + 2);
         // Binary search.
         int32_t l=0, r=glyphCount-1, m;
         int straw, needle=glyph;
         while (l <= r) {
            uint8_t *glyphArray = coverageTable + 4;
            uint16_t glyphID;
            m = (l + r) >> 1;
            glyphID = ttUSHORT(glyphArray + 2 * m);
            straw = glyphID;
            if (needle < straw)
               r = m - 1;
            else if (needle > straw)
               l = m + 1;
            else {
               return m;
            }
         }
         break;
      }
      case 2: {
         uint16_t rangeCount = ttUSHORT(coverageTable + 2);
         uint8_t *rangeArray = coverageTable + 4;
         // Binary search.
         int32_t l=0, r=rangeCount-1, m;
         int strawStart, strawEnd, needle=glyph;
         while (l <= r) {
            uint8_t *rangeRecord;
            m = (l + r) >> 1;
            rangeRecord = rangeArray + 6 * m;
            strawStart = ttUSHORT(rangeRecord);
            strawEnd = ttUSHORT(rangeRecord + 2);
            if (needle < strawStart)
               r = m - 1;
            else if (needle > strawEnd)
               l = m + 1;
            else {
               uint16_t startCoverageIndex = ttUSHORT(rangeRecord + 4);
               return startCoverageIndex + glyph - strawStart;
            }
         }
         break;
      }
      default: return -1; // unsupported
   }
   return -1;
}

static int32_t  stbtt__GetGlyphClass(uint8_t *classDefTable, int glyph)
{
   uint16_t classDefFormat = ttUSHORT(classDefTable);
   switch (classDefFormat)
   {
      case 1: {
         uint16_t startGlyphID = ttUSHORT(classDefTable + 2);
         uint16_t glyphCount = ttUSHORT(classDefTable + 4);
         uint8_t *classDef1ValueArray = classDefTable + 6;
         if (glyph >= startGlyphID && glyph < startGlyphID + glyphCount)
            return (int32_t)ttUSHORT(classDef1ValueArray + 2 * (glyph - startGlyphID));
         break;
      }
      case 2: {
         uint16_t classRangeCount = ttUSHORT(classDefTable + 2);
         uint8_t *classRangeRecords = classDefTable + 4;
         // Binary search.
         int32_t l=0, r=classRangeCount-1, m;
         int strawStart, strawEnd, needle=glyph;
         while (l <= r) {
            uint8_t *classRangeRecord;
            m = (l + r) >> 1;
            classRangeRecord = classRangeRecords + 6 * m;
            strawStart = ttUSHORT(classRangeRecord);
            strawEnd = ttUSHORT(classRangeRecord + 2);
            if (needle < strawStart)
               r = m - 1;
            else if (needle > strawEnd)
               l = m + 1;
            else
               return (int32_t)ttUSHORT(classRangeRecord + 4);
         }
         break;
      }
      default:
         return -1; // Unsupported definition type, return an error.
   }
   // "All glyphs not assigned to a class fall into class 0". (OpenType spec)
   return 0;
}

// Define to ASSERT(x) if you want to break on unimplemented formats.
static int32_t stbtt__GetGlyphGPOSInfoAdvance(const stbtt_fontinfo *info, int glyph1, int glyph2)
{
   uint16_t lookupListOffset;
   uint8_t *lookupList;
   uint16_t lookupCount;
   uint8_t *data;
   int32_t i, sti;
   if (!info->gpos) return 0;
   data = info->data + info->gpos;
   if (ttUSHORT(data+0) != 1) return 0; // Major version 1
   if (ttUSHORT(data+2) != 0) return 0; // Minor version 0
   lookupListOffset = ttUSHORT(data+8);
   lookupList = data + lookupListOffset;
   lookupCount = ttUSHORT(lookupList);
   for (i=0; i<lookupCount; ++i) {
      uint16_t lookupOffset = ttUSHORT(lookupList + 2 + 2 * i);
      uint8_t *lookupTable = lookupList + lookupOffset;
      uint16_t lookupType = ttUSHORT(lookupTable);
      uint16_t subTableCount = ttUSHORT(lookupTable + 4);
      uint8_t *subTableOffsets = lookupTable + 6;
      if (lookupType != 2) // Pair Adjustment Positioning Subtable
         continue;
      for (sti=0; sti<subTableCount; sti++) {
         uint16_t subtableOffset = ttUSHORT(subTableOffsets + 2 * sti);
         uint8_t *table = lookupTable + subtableOffset;
         uint16_t posFormat = ttUSHORT(table);
         uint16_t coverageOffset = ttUSHORT(table + 2);
         int32_t coverageIndex = stbtt__GetCoverageIndex(table + coverageOffset, glyph1);
         if (coverageIndex == -1) continue;
         switch (posFormat) {
            case 1: {
               int32_t l, r, m;
               int straw, needle;
               uint16_t valueFormat1 = ttUSHORT(table + 4);
               uint16_t valueFormat2 = ttUSHORT(table + 6);
               if (valueFormat1 == 4 && valueFormat2 == 0) { // Support more formats?
                  int32_t valueRecordPairSizeInBytes = 2;
                  uint16_t pairSetCount = ttUSHORT(table + 8);
                  uint16_t pairPosOffset = ttUSHORT(table + 10 + 2 * coverageIndex);
                  uint8_t *pairValueTable = table + pairPosOffset;
                  uint16_t pairValueCount = ttUSHORT(pairValueTable);
                  uint8_t *pairValueArray = pairValueTable + 2;
                  if (coverageIndex >= pairSetCount) return 0;
                  needle=glyph2;
                  r=pairValueCount-1;
                  l=0;
                  // Binary search.
                  while (l <= r) {
                     uint16_t secondGlyph;
                     uint8_t *pairValue;
                     m = (l + r) >> 1;
                     pairValue = pairValueArray + (2 + valueRecordPairSizeInBytes) * m;
                     secondGlyph = ttUSHORT(pairValue);
                     straw = secondGlyph;
                     if (needle < straw)
                        r = m - 1;
                     else if (needle > straw)
                        l = m + 1;
                     else {
                        int16_t xAdvance = ttSHORT(pairValue + 2);
                        return xAdvance;
                     }
                  }
               } else
                  return 0;
               break;
            }
            case 2: {
               uint16_t valueFormat1 = ttUSHORT(table + 4);
               uint16_t valueFormat2 = ttUSHORT(table + 6);
               if (valueFormat1 == 4 && valueFormat2 == 0) { // Support more formats?
                  uint16_t classDef1Offset = ttUSHORT(table + 8);
                  uint16_t classDef2Offset = ttUSHORT(table + 10);
                  int glyph1class = stbtt__GetGlyphClass(table + classDef1Offset, glyph1);
                  int glyph2class = stbtt__GetGlyphClass(table + classDef2Offset, glyph2);
                  uint16_t class1Count = ttUSHORT(table + 12);
                  uint16_t class2Count = ttUSHORT(table + 14);
                  uint8_t *class1Records, *class2Records;
                  int16_t xAdvance;
                  if (glyph1class < 0 || glyph1class >= class1Count) return 0; // malformed
                  if (glyph2class < 0 || glyph2class >= class2Count) return 0; // malformed
                  class1Records = table + 16;
                  class2Records = class1Records + 2 * (glyph1class * class2Count);
                  xAdvance = ttSHORT(class2Records + 2 * glyph2class);
                  return xAdvance;
               } else
                  return 0;
               break;
            }
            default:
               return 0; // Unsupported position format
         }
      }
   }
   return 0;
}

int  stbtt_GetGlyphKernAdvance(const stbtt_fontinfo *info, int g1, int g2)
{
   int xAdvance = 0;
   if (info->gpos)
      xAdvance += stbtt__GetGlyphGPOSInfoAdvance(info, g1, g2);
   else if (info->kern)
      xAdvance += stbtt__GetGlyphKernInfoAdvance(info, g1, g2);
   return xAdvance;
}

// an additional amount to add to the 'advance' value between ch1 and ch2
int stbtt_GetCodepointKernAdvance(const stbtt_fontinfo *info, int ch1, int ch2)
{
   if (!info->kern && !info->gpos) // if no kerning table, don't waste time looking up both codepoint->glyphs
      return 0;
   return stbtt_GetGlyphKernAdvance(info, stbtt_FindGlyphIndex(info,ch1), stbtt_FindGlyphIndex(info,ch2));
}

// leftSideBearing is the offset from the current horizontal position to the left edge of the character
// advanceWidth is the offset from the current horizontal position to the next horizontal position
//   these are expressed in unscaled coordinates
void stbtt_GetCodepointHMetrics(const stbtt_fontinfo *info, int codepoint, int *advanceWidth, int *leftSideBearing)
{
   stbtt_GetGlyphHMetrics(info, stbtt_FindGlyphIndex(info,codepoint), advanceWidth, leftSideBearing);
}

// ascent is the coordinate above the baseline the font extends; descent
// is the coordinate below the baseline the font extends (i.e. it is typically negative)
// lineGap is the spacing between one row's descent and the next row's ascent...
// so you should advance the vertical position by "*ascent - *descent + *lineGap"
//   these are expressed in unscaled coordinates, so you must multiply by
//   the scale factor for a given size
void stbtt_GetFontVMetrics(const stbtt_fontinfo *info, int *ascent, int *descent, int *lineGap)
{
   if (ascent ) *ascent  = ttSHORT(info->data+info->hhea + 4);
   if (descent) *descent = ttSHORT(info->data+info->hhea + 6);
   if (lineGap) *lineGap = ttSHORT(info->data+info->hhea + 8);
}

// analogous to GetFontVMetrics, but returns the "typographic" values from the OS/2
// table (specific to MS/Windows TTF files).
//
// Returns 1 on success (table present), 0 on failure.
int  stbtt_GetFontVMetricsOS2(const stbtt_fontinfo *info, int *typoAscent, int *typoDescent, int *typoLineGap)
{
   int tab = stbtt__find_table(info->data, info->fontstart, "OS/2");
   if (!tab)
      return 0;
   if (typoAscent ) *typoAscent  = ttSHORT(info->data+tab + 68);
   if (typoDescent) *typoDescent = ttSHORT(info->data+tab + 70);
   if (typoLineGap) *typoLineGap = ttSHORT(info->data+tab + 72);
   return 1;
}

// the bounding box around all possible characters
void stbtt_GetFontBoundingBox(const stbtt_fontinfo *info, int *x0, int *y0, int *x1, int *y1)
{
   *x0 = ttSHORT(info->data + info->head + 36);
   *y0 = ttSHORT(info->data + info->head + 38);
   *x1 = ttSHORT(info->data + info->head + 40);
   *y1 = ttSHORT(info->data + info->head + 42);
}

// computes a scale factor to produce a font whose "height" is 'pixels' tall.
// Height is measured as the distance from the highest ascender to the lowest
// descender; in other words, it's equivalent to calling stbtt_GetFontVMetrics
// and computing:
//       scale = pixels / (ascent - descent)
// so if you prefer to measure height by the ascent only, use a similar calculation.
float stbtt_ScaleForPixelHeight(const stbtt_fontinfo *info, float height)
{
   int fheight = ttSHORT(info->data + info->hhea + 4) - ttSHORT(info->data + info->hhea + 6);
   return (float) height / fheight;
}

// computes a scale factor to produce a font whose EM size is mapped to
// 'pixels' tall. This is probably what traditional APIs compute, but
// I'm not positive.
float stbtt_ScaleForMappingEmToPixels(const stbtt_fontinfo *info, float pixels)
{
   int unitsPerEm = ttUSHORT(info->data + info->head + 18);
   return pixels / unitsPerEm;
}

// frees the data allocated above
void stbtt_FreeShape(const stbtt_fontinfo *info, stbtt_vertex *v)
{
   STBTT_free(v, info->userdata);
}

uint8_t *stbtt_FindSVGDoc(const stbtt_fontinfo *info, int gl)
{
   int i;
   uint8_t *data = info->data;
   uint8_t *svg_doc_list = data + stbtt__get_svg((stbtt_fontinfo *) info);
   int numEntries = ttUSHORT(svg_doc_list);
   uint8_t *svg_docs = svg_doc_list + 2;
   for(i=0; i<numEntries; i++) {
      uint8_t *svg_doc = svg_docs + (12 * i);
      if ((gl >= ttUSHORT(svg_doc)) && (gl <= ttUSHORT(svg_doc + 2)))
         return svg_doc;
   }
   return 0;
}

// fills svg with the character's SVG data.
// returns data size or 0 if SVG not found.
int stbtt_GetGlyphSVG(const stbtt_fontinfo *info, int gl, const char **svg)
{
   uint8_t *data = info->data;
   uint8_t *svg_doc;
   if (info->svg == 0)
      return 0;
   svg_doc = stbtt_FindSVGDoc(info, gl);
   if (svg_doc != NULL) {
      *svg = (char *) data + info->svg + ttULONG(svg_doc + 4);
      return ttULONG(svg_doc + 8);
   } else {
      return 0;
   }
}

int stbtt_GetCodepointSVG(const stbtt_fontinfo *info, int unicode_codepoint, const char **svg)
{
   return stbtt_GetGlyphSVG(info, stbtt_FindGlyphIndex(info, unicode_codepoint), svg);
}

//////////////////////////////////////////////////////////////////////////////
//
// antialiasing software rasterizer
//

void stbtt_GetGlyphBitmapBoxSubpixel(const stbtt_fontinfo *font, int glyph,
                                     float scale_x, float scale_y,
                                     float shift_x, float shift_y, int *ix0,
                                     int *iy0, int *ix1, int *iy1)
{
   int x0=0,y0=0,x1,y1; // =0 suppresses compiler warning
   if (!stbtt_GetGlyphBox(font, glyph, &x0,&y0,&x1,&y1)) {
      // e.g. space character
      if (ix0) *ix0 = 0;
      if (iy0) *iy0 = 0;
      if (ix1) *ix1 = 0;
      if (iy1) *iy1 = 0;
   } else {
      // move to integral bboxes (treating pixels as little squares, what pixels get touched)?
      if (ix0) *ix0 = STBTT_ifloor( x0 * scale_x + shift_x);
      if (iy0) *iy0 = STBTT_ifloor(-y1 * scale_y + shift_y);
      if (ix1) *ix1 = STBTT_iceil ( x1 * scale_x + shift_x);
      if (iy1) *iy1 = STBTT_iceil (-y0 * scale_y + shift_y);
   }
}

void stbtt_GetGlyphBitmapBox(const stbtt_fontinfo *font, int glyph,
                             float scale_x, float scale_y, int *ix0, int *iy0,
                             int *ix1, int *iy1)
{
   stbtt_GetGlyphBitmapBoxSubpixel(font, glyph, scale_x, scale_y,0.0f,0.0f, ix0, iy0, ix1, iy1);
}

// same as stbtt_GetCodepointBitmapBox, but you can specify a subpixel
// shift for the character
void stbtt_GetCodepointBitmapBoxSubpixel(const stbtt_fontinfo *font,
                                         int codepoint, float scale_x,
                                         float scale_y, float shift_x,
                                         float shift_y, int *ix0, int *iy0,
                                         int *ix1, int *iy1)
{
   stbtt_GetGlyphBitmapBoxSubpixel(font, stbtt_FindGlyphIndex(font,codepoint), scale_x, scale_y,shift_x,shift_y, ix0,iy0,ix1,iy1);
}

// get the bbox of the bitmap centered around the glyph origin; so the
// bitmap width is ix1-ix0, height is iy1-iy0, and location to place
// the bitmap top left is (leftSideBearing*scale,iy0).
// (Note that the bitmap uses y-increases-down, but the shape uses
// y-increases-up, so CodepointBitmapBox and CodepointBox are inverted.)
void stbtt_GetCodepointBitmapBox(const stbtt_fontinfo *font, int codepoint,
                                 float scale_x, float scale_y, int *ix0,
                                 int *iy0, int *ix1, int *iy1)
{
   stbtt_GetCodepointBitmapBoxSubpixel(font, codepoint, scale_x, scale_y,0.0f,0.0f, ix0,iy0,ix1,iy1);
}

//////////////////////////////////////////////////////////////////////////////
//
//  Rasterizer

static void *stbtt__hheap_alloc(stbtt__hheap *hh, size_t size, void *userdata)
{
   if (hh->first_free) {
      void *p = hh->first_free;
      hh->first_free = * (void **) p;
      return p;
   } else {
      if (hh->num_remaining_in_head_chunk == 0) {
         int count = (size < 32 ? 2000 : size < 128 ? 800 : 100);
         stbtt__hheap_chunk *c = STBTT_malloc(sizeof(stbtt__hheap_chunk) + size * count, userdata);
         if (c == NULL)
            return NULL;
         c->next = hh->head;
         hh->head = c;
         hh->num_remaining_in_head_chunk = count;
      }
      --hh->num_remaining_in_head_chunk;
      return (char *) (hh->head) + sizeof(stbtt__hheap_chunk) + size * hh->num_remaining_in_head_chunk;
   }
}

static void stbtt__hheap_STBTT_free(stbtt__hheap *hh, void *p)
{
   *(void **) p = hh->first_free;
   hh->first_free = p;
}

static void stbtt__hheap_cleanup(stbtt__hheap *hh, void *userdata)
{
   stbtt__hheap_chunk *c = hh->head;
   while (c) {
      stbtt__hheap_chunk *n = c->next;
      STBTT_free(c, userdata);
      c = n;
   }
}

#if STBTT_RASTERIZER_VERSION == 1
#define STBTT_FIXSHIFT   10
#define STBTT_FIX        (1 << STBTT_FIXSHIFT)
#define STBTT_FIXMASK    (STBTT_FIX-1)

static stbtt__active_edge *stbtt__new_active(stbtt__hheap *hh, stbtt__edge *e,
                                             int off_x, float start_point,
                                             void *userdata)
{
   stbtt__active_edge *z = (stbtt__active_edge *) stbtt__hheap_alloc(hh, sizeof(*z), userdata);
   float dxdy = (e->x1 - e->x0) / (e->y1 - e->y0);
   ASSERT(z != NULL);
   if (!z) return z;
   // round dx down to avoid overshooting
   if (dxdy < 0) {
      z->dx = -STBTT_ifloor(STBTT_FIX * -dxdy);
   } else {
      z->dx = STBTT_ifloor(STBTT_FIX * dxdy);
   }
   z->x = STBTT_ifloor(STBTT_FIX * e->x0 + z->dx * (start_point - e->y0)); // use z->dx so when we offset later it's by the same amount
   z->x -= off_x * STBTT_FIX;
   z->ey = e->y1;
   z->next = 0;
   z->direction = e->invert ? 1 : -1;
   return z;
}

#elif STBTT_RASTERIZER_VERSION == 2

static stbtt__active_edge *stbtt__new_active(stbtt__hheap *hh, stbtt__edge *e,
                                             int off_x, float start_point,
                                             void *userdata)
{
   stbtt__active_edge *z = (stbtt__active_edge *) stbtt__hheap_alloc(hh, sizeof(*z), userdata);
   float dxdy = (e->x1 - e->x0) / (e->y1 - e->y0);
   ASSERT(z != NULL);
   //ASSERT(e->y0 <= start_point);
   if (!z) return z;
   z->fdx = dxdy;
   z->fdy = dxdy != 0.0f ? (1.0f/dxdy) : 0.0f;
   z->fx = e->x0 + dxdy * (start_point - e->y0);
   z->fx -= off_x;
   z->direction = e->invert ? 1.0f : -1.0f;
   z->sy = e->y0;
   z->ey = e->y1;
   z->next = 0;
   return z;
}

#else
#error "Unrecognized value of STBTT_RASTERIZER_VERSION"
#endif

#if STBTT_RASTERIZER_VERSION == 1
// note: this routine clips fills that extend off the edges... ideally this
// wouldn't happen, but it could happen if the truetype glyph bounding boxes
// are wrong, or if the user supplies a too-small bitmap
static void stbtt__fill_active_edges(unsigned char *scanline, int len,
                                     stbtt__active_edge *e, int max_weight)
{
   // non-zero winding fill
   int x0=0, w=0;
   while (e) {
      if (w == 0) {
         // if we're currently at zero, we need to record the edge start point
         x0 = e->x; w += e->direction;
      } else {
         int x1 = e->x; w += e->direction;
         // if we went to zero, we need to draw
         if (w == 0) {
            int i = x0 >> STBTT_FIXSHIFT;
            int j = x1 >> STBTT_FIXSHIFT;
            if (i < len && j >= 0) {
               if (i == j) {
                  // x0,x1 are the same pixel, so compute combined coverage
                  scanline[i] = scanline[i] + (uint8_t) ((x1 - x0) * max_weight >> STBTT_FIXSHIFT);
               } else {
                  if (i >= 0) // add antialiasing for x0
                     scanline[i] = scanline[i] + (uint8_t) (((STBTT_FIX - (x0 & STBTT_FIXMASK)) * max_weight) >> STBTT_FIXSHIFT);
                  else
                     i = -1; // clip
                  if (j < len) // add antialiasing for x1
                     scanline[j] = scanline[j] + (uint8_t) (((x1 & STBTT_FIXMASK) * max_weight) >> STBTT_FIXSHIFT);
                  else
                     j = len; // clip
                  for (++i; i < j; ++i) // fill pixels between x0 and x1
                     scanline[i] = scanline[i] + (uint8_t) max_weight;
               }
            }
         }
      }
      e = e->next;
   }
}

static void stbtt__rasterize_sorted_edges(stbtt__bitmap *result, stbtt__edge *e,
                                          int n, int vsubsample, int off_x,
                                          int off_y, void *userdata)
{
   stbtt__hheap hh = { 0, 0, 0 };
   stbtt__active_edge *active = NULL;
   int y,j=0;
   int max_weight = (255 / vsubsample);  // weight per vertical scanline
   int s; // vertical subsample index
   unsigned char scanline_data[512], *scanline;
   if (result->w > 512)
      scanline = STBTT_malloc(result->w, userdata);
   else
      scanline = scanline_data;
   y = off_y * vsubsample;
   e[n].y0 = (off_y + result->h) * (float) vsubsample + 1;
   while (j < result->h) {
      memset(scanline, 0, result->w);
      for (s=0; s < vsubsample; ++s) {
         // find center of pixel for this scanline
         float scan_y = y + 0.5f;
         stbtt__active_edge **step = &active;
         // update all active edges;
         // remove all active edges that terminate before the center of this scanline
         while (*step) {
            stbtt__active_edge * z = *step;
            if (z->ey <= scan_y) {
               *step = z->next; // delete from list
               ASSERT(z->direction);
               z->direction = 0;
               stbtt__hheap_STBTT_free(&hh, z);
            } else {
               z->x += z->dx; // advance to position for current scanline
               step = &((*step)->next); // advance through list
            }
         }
         // resort the list if needed
         for(;;) {
            int changed=0;
            step = &active;
            while (*step && (*step)->next) {
               if ((*step)->x > (*step)->next->x) {
                  stbtt__active_edge *t = *step;
                  stbtt__active_edge *q = t->next;
                  t->next = q->next;
                  q->next = t;
                  *step = q;
                  changed = 1;
               }
               step = &(*step)->next;
            }
            if (!changed) break;
         }
         // insert all edges that start before the center of this scanline -- omit ones that also end on this scanline
         while (e->y0 <= scan_y) {
            if (e->y1 > scan_y) {
               stbtt__active_edge *z = stbtt__new_active(&hh, e, off_x, scan_y, userdata);
               if (z != NULL) {
                  // find insertion point
                  if (active == NULL)
                     active = z;
                  else if (z->x < active->x) {
                     // insert at front
                     z->next = active;
                     active = z;
                  } else {
                     // find thing to insert AFTER
                     stbtt__active_edge *p = active;
                     while (p->next && p->next->x < z->x)
                        p = p->next;
                     // at this point, p->next->x is NOT < z->x
                     z->next = p->next;
                     p->next = z;
                  }
               }
            }
            ++e;
         }
         // now process all active edges in XOR fashion
         if (active)
            stbtt__fill_active_edges(scanline, result->w, active, max_weight);
         ++y;
      }
      memcpy(result->pixels + j * result->stride, scanline, result->w);
      ++j;
   }
   stbtt__hheap_cleanup(&hh, userdata);
   if (scanline != scanline_data)
      STBTT_free(scanline, userdata);
}

#elif STBTT_RASTERIZER_VERSION == 2

// the edge passed in here does not cross the vertical line at x or the vertical line at x+1
// (i.e. it has already been clipped to those)
static void stbtt__handle_clipped_edge(float *scanline, int x,
                                       stbtt__active_edge *e, float x0,
                                       float y0, float x1, float y1)
{
   if (y0 == y1) return;
   ASSERT(y0 < y1);
   ASSERT(e->sy <= e->ey);
   if (y0 > e->ey) return;
   if (y1 < e->sy) return;
   if (y0 < e->sy) {
      x0 += (x1-x0) * (e->sy - y0) / (y1-y0);
      y0 = e->sy;
   }
   if (y1 > e->ey) {
      x1 += (x1-x0) * (e->ey - y1) / (y1-y0);
      y1 = e->ey;
   }
   if (x0 == x) {
      ASSERT(x1 <= x+1);
   } else if (x0 == x+1) {
      ASSERT(x1 >= x);
   } else if (x0 <= x) {
      ASSERT(x1 <= x);
   } else if (x0 >= x+1) {
      ASSERT(x1 >= x+1);
   } else {
      ASSERT(x1 >= x && x1 <= x+1);
   }
   if (x0 <= x && x1 <= x) {
      scanline[x] += e->direction * (y1-y0);
   } else if (!(x0 >= x+1 && x1 >= x+1)) {
      ASSERT(x0 >= x && x0 <= x+1 && x1 >= x && x1 <= x+1);
      scanline[x] += e->direction * (y1-y0) * (1-((x0-x)+(x1-x))/2); // coverage = 1 - average x position
   }
}

static float stbtt__sized_trapezoid_area(float height, float top_width, float bottom_width)
{
   ASSERT(top_width >= 0);
   ASSERT(bottom_width >= 0);
   return (top_width + bottom_width) / 2.0f * height;
}

static float stbtt__position_trapezoid_area(float height, float tx0, float tx1, float bx0, float bx1)
{
   return stbtt__sized_trapezoid_area(height, tx1 - tx0, bx1 - bx0);
}

static float stbtt__sized_triangle_area(float height, float width)
{
   return height * width / 2;
}

static void stbtt__fill_active_edges_new(float *scanline, float *scanline_fill,
                                         int len, stbtt__active_edge *e,
                                         float y_top)
{
   float y_bottom = y_top+1;
   while (e) {
      // brute force every pixel
      // compute intersection points with top & bottom
      ASSERT(e->ey >= y_top);
      if (e->fdx == 0) {
         float x0 = e->fx;
         if (x0 < len) {
            if (x0 >= 0) {
               stbtt__handle_clipped_edge(scanline,(int) x0,e, x0,y_top, x0,y_bottom);
               stbtt__handle_clipped_edge(scanline_fill-1,(int) x0+1,e, x0,y_top, x0,y_bottom);
            } else {
               stbtt__handle_clipped_edge(scanline_fill-1,0,e, x0,y_top, x0,y_bottom);
            }
         }
      } else {
         float x0 = e->fx;
         float dx = e->fdx;
         float xb = x0 + dx;
         float x_top, x_bottom;
         float sy0,sy1;
         float dy = e->fdy;
         ASSERT(e->sy <= y_bottom && e->ey >= y_top);
         // compute endpoints of line segment clipped to this scanline (if the
         // line segment starts on this scanline. x0 is the intersection of the
         // line with y_top, but that may be off the line segment.
         if (e->sy > y_top) {
            x_top = x0 + dx * (e->sy - y_top);
            sy0 = e->sy;
         } else {
            x_top = x0;
            sy0 = y_top;
         }
         if (e->ey < y_bottom) {
            x_bottom = x0 + dx * (e->ey - y_top);
            sy1 = e->ey;
         } else {
            x_bottom = xb;
            sy1 = y_bottom;
         }
         if (x_top >= 0 && x_bottom >= 0 && x_top < len && x_bottom < len) {
            // from here on, we don't have to range check x values
            if ((int) x_top == (int) x_bottom) {
               float height;
               // simple case, only spans one pixel
               int x = (int) x_top;
               height = (sy1 - sy0) * e->direction;
               ASSERT(x >= 0 && x < len);
               scanline[x]      += stbtt__position_trapezoid_area(height, x_top, x+1.0f, x_bottom, x+1.0f);
               scanline_fill[x] += height; // everything right of this pixel is filled
            } else {
               int x,x1,x2;
               float y_crossing, y_final, step, sign, area;
               // covers 2+ pixels
               if (x_top > x_bottom) {
                  // flip scanline vertically; signed area is the same
                  float t;
                  sy0 = y_bottom - (sy0 - y_top);
                  sy1 = y_bottom - (sy1 - y_top);
                  t = sy0, sy0 = sy1, sy1 = t;
                  t = x_bottom, x_bottom = x_top, x_top = t;
                  dx = -dx;
                  dy = -dy;
                  t = x0, x0 = xb, xb = t;
               }
               ASSERT(dy >= 0);
               ASSERT(dx >= 0);
               x1 = (int) x_top;
               x2 = (int) x_bottom;
               // compute intersection with y axis at x1+1
               y_crossing = y_top + dy * (x1+1 - x0);
               // compute intersection with y axis at x2
               y_final = y_top + dy * (x2 - x0);
               //           x1    x_top                            x2    x_bottom
               //     y_top  +------|-----+------------+------------+--------|---+------------+
               //            |            |            |            |            |            |
               //            |            |            |            |            |            |
               //       sy0  |      Txxxxx|............|............|............|............|
               // y_crossing |            *xxxxx.......|............|............|............|
               //            |            |     xxxxx..|............|............|............|
               //            |            |     /-   xx*xxxx........|............|............|
               //            |            | dy <       |    xxxxxx..|............|............|
               //   y_final  |            |     \-     |          xx*xxx.........|............|
               //       sy1  |            |            |            |   xxxxxB...|............|
               //            |            |            |            |            |            |
               //            |            |            |            |            |            |
               //  y_bottom  +------------+------------+------------+------------+------------+
               //
               // goal is to measure the area covered by '.' in each pixel
               // if x2 is right at the right edge of x1, y_crossing can blow up, github #1057
               // @TODO: maybe test against sy1 rather than y_bottom?
               if (y_crossing > y_bottom)
                  y_crossing = y_bottom;
               sign = e->direction;
               // area of the rectangle covered from sy0..y_crossing
               area = sign * (y_crossing-sy0);
               // area of the triangle (x_top,sy0), (x1+1,sy0), (x1+1,y_crossing)
               scanline[x1] += stbtt__sized_triangle_area(area, x1+1 - x_top);
               // check if final y_crossing is blown up; no test case for this
               if (y_final > y_bottom) {
                  y_final = y_bottom;
                  dy = (y_final - y_crossing ) / (x2 - (x1+1)); // if denom=0, y_final = y_crossing, so y_final <= y_bottom
               }
               // in second pixel, area covered by line segment found in first pixel
               // is always a rectangle 1 wide * the height of that line segment; this
               // is exactly what the variable 'area' stores. it also gets a contribution
               // from the line segment within it. the THIRD pixel will get the first
               // pixel's rectangle contribution, the second pixel's rectangle contribution,
               // and its own contribution. the 'own contribution' is the same in every pixel except
               // the leftmost and rightmost, a trapezoid that slides down in each pixel.
               // the second pixel's contribution to the third pixel will be the
               // rectangle 1 wide times the height change in the second pixel, which is dy.
               step = sign * dy * 1; // dy is dy/dx, change in y for every 1 change in x,
               // which multiplied by 1-pixel-width is how much pixel area changes for each step in x
               // so the area advances by 'step' every time
               for (x = x1+1; x < x2; ++x) {
                  scanline[x] += area + step/2; // area of trapezoid is 1*step/2
                  area += step;
               }
               ASSERT(fabs(area) <= 1.01f); // accumulated error from area += step unless we round step down
               ASSERT(sy1 > y_final-0.01f);
               // area covered in the last pixel is the rectangle from all the pixels to the left,
               // plus the trapezoid filled by the line segment in this pixel all the way to the right edge
               scanline[x2] += area + sign * stbtt__position_trapezoid_area(sy1-y_final, (float) x2, x2+1.0f, x_bottom, x2+1.0f);
               // the rest of the line is filled based on the total height of the line segment in this pixel
               scanline_fill[x2] += sign * (sy1-sy0);
            }
         } else {
            // if edge goes outside of box we're drawing, we require
            // clipping logic. since this does not match the intended use
            // of this library, we use a different, very slow brute
            // force implementation
            // note though that this does happen some of the time because
            // x_top and x_bottom can be extrapolated at the top & bottom of
            // the shape and actually lie outside the bounding box
            int x;
            for (x=0; x < len; ++x) {
               // cases:
               //
               // there can be up to two intersections with the pixel. any intersection
               // with left or right edges can be handled by splitting into two (or three)
               // regions. intersections with top & bottom do not necessitate case-wise logic.
               //
               // the old way of doing this found the intersections with the left & right edges,
               // then used some simple logic to produce up to three segments in sorted order
               // from top-to-bottom. however, this had a problem: if an x edge was epsilon
               // across the x border, then the corresponding y position might not be distinct
               // from the other y segment, and it might ignored as an empty segment. to avoid
               // that, we need to explicitly produce segments based on x positions.
               // rename variables to clearly-defined pairs
               float y0 = y_top;
               float x1 = (float) (x);
               float x2 = (float) (x+1);
               float x3 = xb;
               float y3 = y_bottom;
               // x = e->x + e->dx * (y-y_top)
               // (y-y_top) = (x - e->x) / e->dx
               // y = (x - e->x) / e->dx + y_top
               float y1 = (x - x0) / dx + y_top;
               float y2 = (x+1 - x0) / dx + y_top;
               if (x0 < x1 && x3 > x2) {         // three segments descending down-right
                  stbtt__handle_clipped_edge(scanline,x,e, x0,y0, x1,y1);
                  stbtt__handle_clipped_edge(scanline,x,e, x1,y1, x2,y2);
                  stbtt__handle_clipped_edge(scanline,x,e, x2,y2, x3,y3);
               } else if (x3 < x1 && x0 > x2) {  // three segments descending down-left
                  stbtt__handle_clipped_edge(scanline,x,e, x0,y0, x2,y2);
                  stbtt__handle_clipped_edge(scanline,x,e, x2,y2, x1,y1);
                  stbtt__handle_clipped_edge(scanline,x,e, x1,y1, x3,y3);
               } else if (x0 < x1 && x3 > x1) {  // two segments across x, down-right
                  stbtt__handle_clipped_edge(scanline,x,e, x0,y0, x1,y1);
                  stbtt__handle_clipped_edge(scanline,x,e, x1,y1, x3,y3);
               } else if (x3 < x1 && x0 > x1) {  // two segments across x, down-left
                  stbtt__handle_clipped_edge(scanline,x,e, x0,y0, x1,y1);
                  stbtt__handle_clipped_edge(scanline,x,e, x1,y1, x3,y3);
               } else if (x0 < x2 && x3 > x2) {  // two segments across x+1, down-right
                  stbtt__handle_clipped_edge(scanline,x,e, x0,y0, x2,y2);
                  stbtt__handle_clipped_edge(scanline,x,e, x2,y2, x3,y3);
               } else if (x3 < x2 && x0 > x2) {  // two segments across x+1, down-left
                  stbtt__handle_clipped_edge(scanline,x,e, x0,y0, x2,y2);
                  stbtt__handle_clipped_edge(scanline,x,e, x2,y2, x3,y3);
               } else {  // one segment
                  stbtt__handle_clipped_edge(scanline,x,e, x0,y0, x3,y3);
               }
            }
         }
      }
      e = e->next;
   }
}

// directly AA rasterize edges w/o supersampling
static void stbtt__rasterize_sorted_edges(stbtt__bitmap *result, stbtt__edge *e,
                                          int n, int vsubsample, int off_x,
                                          int off_y, void *userdata)
{
   stbtt__hheap hh = { 0, 0, 0 };
   stbtt__active_edge *active = NULL;
   int y,j=0, i;
   float scanline_data[129], *scanline, *scanline2;
   if (result->w > 64)
      scanline = STBTT_malloc((result->w*2+1) * sizeof(float), userdata);
   else
      scanline = scanline_data;
   scanline2 = scanline + result->w;
   y = off_y;
   e[n].y0 = (float) (off_y + result->h) + 1;
   while (j < result->h) {
      // find center of pixel for this scanline
      float scan_y_top    = y + 0.0f;
      float scan_y_bottom = y + 1.0f;
      stbtt__active_edge **step = &active;
      memset(scanline , 0, result->w*sizeof(scanline[0]));
      memset(scanline2, 0, (result->w+1)*sizeof(scanline[0]));
      // update all active edges;
      // remove all active edges that terminate before the top of this scanline
      while (*step) {
         stbtt__active_edge * z = *step;
         if (z->ey <= scan_y_top) {
            *step = z->next; // delete from list
            ASSERT(z->direction);
            z->direction = 0;
            stbtt__hheap_STBTT_free(&hh, z);
         } else {
            step = &((*step)->next); // advance through list
         }
      }
      // insert all edges that start before the bottom of this scanline
      while (e->y0 <= scan_y_bottom) {
         if (e->y0 != e->y1) {
            stbtt__active_edge *z = stbtt__new_active(&hh, e, off_x, scan_y_top, userdata);
            if (z != NULL) {
               if (j == 0 && off_y != 0) {
                  if (z->ey < scan_y_top) {
                     // this can happen due to subpixel positioning and some kind of fp rounding error i think
                     z->ey = scan_y_top;
                  }
               }
               ASSERT(z->ey >= scan_y_top); // if we get really unlucky a tiny bit of an edge can be out of bounds
               // insert at front
               z->next = active;
               active = z;
            }
         }
         ++e;
      }
      // now process all active edges
      if (active)
         stbtt__fill_active_edges_new(scanline, scanline2+1, result->w, active, scan_y_top);
      {
         float sum = 0;
         for (i=0; i < result->w; ++i) {
            float k;
            int m;
            sum += scanline2[i];
            k = scanline[i] + sum;
            k = (float) fabs(k)*255 + 0.5f;
            m = (int) k;
            if (m > 255) m = 255;
            result->pixels[j*result->stride + i] = (unsigned char) m;
         }
      }
      // advance all the edges
      step = &active;
      while (*step) {
         stbtt__active_edge *z = *step;
         z->fx += z->fdx; // advance to position for current scanline
         step = &((*step)->next); // advance through list
      }
      ++y;
      ++j;
   }
   stbtt__hheap_cleanup(&hh, userdata);
   if (scanline != scanline_data)
      STBTT_free(scanline, userdata);
}
#else
#error "Unrecognized value of STBTT_RASTERIZER_VERSION"
#endif

#define STBTT__COMPARE(a,b)  ((a)->y0 < (b)->y0)

static void stbtt__sort_edges_ins_sort(stbtt__edge *p, int n)
{
   int i,j;
   for (i=1; i < n; ++i) {
      stbtt__edge t = p[i], *a = &t;
      j = i;
      while (j > 0) {
         stbtt__edge *b = &p[j-1];
         int c = STBTT__COMPARE(a,b);
         if (!c) break;
         p[j] = p[j-1];
         --j;
      }
      if (i != j)
         p[j] = t;
   }
}

static void stbtt__sort_edges_quicksort(stbtt__edge *p, int n)
{
   /* threshold for transitioning to insertion sort */
   while (n > 12) {
      stbtt__edge t;
      int c01,c12,c,m,i,j;
      /* compute median of three */
      m = n >> 1;
      c01 = STBTT__COMPARE(&p[0],&p[m]);
      c12 = STBTT__COMPARE(&p[m],&p[n-1]);
      /* if 0 >= mid >= end, or 0 < mid < end, then use mid */
      if (c01 != c12) {
         /* otherwise, we'll need to swap something else to middle */
         int z;
         c = STBTT__COMPARE(&p[0],&p[n-1]);
         /* 0>mid && mid<n:  0>n => n; 0<n => 0 */
         /* 0<mid && mid>n:  0>n => 0; 0<n => n */
         z = (c == c12) ? 0 : n-1;
         t = p[z];
         p[z] = p[m];
         p[m] = t;
      }
      /* now p[m] is the median-of-three */
      /* swap it to the beginning so it won't move around */
      t = p[0];
      p[0] = p[m];
      p[m] = t;
      /* partition loop */
      i=1;
      j=n-1;
      for(;;) {
         /* handling of equality is crucial here */
         /* for sentinels & efficiency with duplicates */
         for (;;++i) {
            if (!STBTT__COMPARE(&p[i], &p[0])) break;
         }
         for (;;--j) {
            if (!STBTT__COMPARE(&p[0], &p[j])) break;
         }
         /* make sure we haven't crossed */
         if (i >= j) break;
         t = p[i];
         p[i] = p[j];
         p[j] = t;
         ++i;
         --j;
      }
      /* recurse on smaller side, iterate on larger */
      if (j < (n-i)) {
         stbtt__sort_edges_quicksort(p,j);
         p = p+i;
         n = n-i;
      } else {
         stbtt__sort_edges_quicksort(p+i, n-i);
         n = j;
      }
   }
}

static void stbtt__sort_edges(stbtt__edge *p, int n)
{
   stbtt__sort_edges_quicksort(p, n);
   stbtt__sort_edges_ins_sort(p, n);
}

static void stbtt__rasterize(stbtt__bitmap *result, stbtt__point *pts,
                             int *wcount, int windings, float scale_x,
                             float scale_y, float shift_x, float shift_y,
                             int off_x, int off_y, int invert, void *userdata)
{
   float y_scale_inv = invert ? -scale_y : scale_y;
   stbtt__edge *e;
   int n,i,j,k,m;
#if STBTT_RASTERIZER_VERSION == 1
   int vsubsample = result->h < 8 ? 15 : 5;
#elif STBTT_RASTERIZER_VERSION == 2
   int vsubsample = 1;
#else
   #error "Unrecognized value of STBTT_RASTERIZER_VERSION"
#endif
   // vsubsample should divide 255 evenly; otherwise we won't reach full opacity
   // now we have to blow out the windings into explicit edge lists
   n = 0;
   for (i=0; i < windings; ++i)
      n += wcount[i];
   e = STBTT_malloc(sizeof(*e) * (n+1), userdata); // add an extra one as a sentinel
   if (e == 0) return;
   n = 0;
   m=0;
   for (i=0; i < windings; ++i) {
      stbtt__point *p = pts + m;
      m += wcount[i];
      j = wcount[i]-1;
      for (k=0; k < wcount[i]; j=k++) {
         int a=k,b=j;
         // skip the edge if horizontal
         if (p[j].y == p[k].y)
            continue;
         // add edge from j to k to the list
         e[n].invert = 0;
         if (invert ? p[j].y > p[k].y : p[j].y < p[k].y) {
            e[n].invert = 1;
            a=j,b=k;
         }
         e[n].x0 = p[a].x * scale_x + shift_x;
         e[n].y0 = (p[a].y * y_scale_inv + shift_y) * vsubsample;
         e[n].x1 = p[b].x * scale_x + shift_x;
         e[n].y1 = (p[b].y * y_scale_inv + shift_y) * vsubsample;
         ++n;
      }
   }
   // now sort the edges by their highest point (should snap to integer, and then by x)
   //STBTT_sort(e, n, sizeof(e[0]), stbtt__edge_compare);
   stbtt__sort_edges(e, n);
   // now, traverse the scanlines and find the intersections on each scanline, use xor winding rule
   stbtt__rasterize_sorted_edges(result, e, n, vsubsample, off_x, off_y, userdata);
   STBTT_free(e, userdata);
}

static void stbtt__add_point(stbtt__point *points, int n, float x, float y)
{
   if (!points) return; // during first pass, it's unallocated
   points[n].x = x;
   points[n].y = y;
}

// tessellate until threshold p is happy... @TODO warped to compensate for non-linear stretching
static int stbtt__tesselate_curve(stbtt__point *points, int *num_points,
                                  float x0, float y0, float x1, float y1,
                                  float x2, float y2,
                                  float objspace_flatness_squared, int n)
{
   // midpoint
   float mx = (x0 + 2*x1 + x2)/4;
   float my = (y0 + 2*y1 + y2)/4;
   // versus directly drawn line
   float dx = (x0+x2)/2 - mx;
   float dy = (y0+y2)/2 - my;
   if (n > 16) // 65536 segments on one curve better be enough!
      return 1;
   if (dx*dx+dy*dy > objspace_flatness_squared) { // half-pixel error allowed... need to be smaller if AA
      stbtt__tesselate_curve(points, num_points, x0,y0, (x0+x1)/2.0f,(y0+y1)/2.0f, mx,my, objspace_flatness_squared,n+1);
      stbtt__tesselate_curve(points, num_points, mx,my, (x1+x2)/2.0f,(y1+y2)/2.0f, x2,y2, objspace_flatness_squared,n+1);
   } else {
      stbtt__add_point(points, *num_points,x2,y2);
      *num_points = *num_points+1;
   }
   return 1;
}

static void stbtt__tesselate_cubic(stbtt__point *points, int *num_points,
                                   float x0, float y0, float x1, float y1,
                                   float x2, float y2, float x3, float y3,
                                   float objspace_flatness_squared, int n)
{
   // @TODO this "flatness" calculation is just made-up nonsense that seems to work well enough
   float dx0 = x1-x0;
   float dy0 = y1-y0;
   float dx1 = x2-x1;
   float dy1 = y2-y1;
   float dx2 = x3-x2;
   float dy2 = y3-y2;
   float dx = x3-x0;
   float dy = y3-y0;
   float longlen = (float) (sqrt(dx0*dx0+dy0*dy0)+sqrt(dx1*dx1+dy1*dy1)+sqrt(dx2*dx2+dy2*dy2));
   float shortlen = (float) sqrt(dx*dx+dy*dy);
   float flatness_squared = longlen*longlen-shortlen*shortlen;
   if (n > 16) // 65536 segments on one curve better be enough!
      return;
   if (flatness_squared > objspace_flatness_squared) {
      float x01 = (x0+x1)/2;
      float y01 = (y0+y1)/2;
      float x12 = (x1+x2)/2;
      float y12 = (y1+y2)/2;
      float x23 = (x2+x3)/2;
      float y23 = (y2+y3)/2;
      float xa = (x01+x12)/2;
      float ya = (y01+y12)/2;
      float xb = (x12+x23)/2;
      float yb = (y12+y23)/2;
      float mx = (xa+xb)/2;
      float my = (ya+yb)/2;
      stbtt__tesselate_cubic(points, num_points, x0,y0, x01,y01, xa,ya, mx,my, objspace_flatness_squared,n+1);
      stbtt__tesselate_cubic(points, num_points, mx,my, xb,yb, x23,y23, x3,y3, objspace_flatness_squared,n+1);
   } else {
      stbtt__add_point(points, *num_points,x3,y3);
      *num_points = *num_points+1;
   }
}

// returns number of contours
static stbtt__point *stbtt_FlattenCurves(stbtt_vertex *vertices, int num_verts,
                                         float objspace_flatness,
                                         int **contour_lengths,
                                         int *num_contours, void *userdata)
{
   stbtt__point *points=0;
   int num_points=0;
   float objspace_flatness_squared = objspace_flatness * objspace_flatness;
   int i,n=0,start=0, pass;
   // count how many "moves" there are to get the contour count
   for (i=0; i < num_verts; ++i)
      if (vertices[i].type == STBTT_vmove)
         ++n;
   *num_contours = n;
   if (n == 0) return 0;
   *contour_lengths = STBTT_malloc(sizeof(**contour_lengths) * n, userdata);
   if (*contour_lengths == 0) {
      *num_contours = 0;
      return 0;
   }
   // make two passes through the points so we don't need to realloc
   for (pass=0; pass < 2; ++pass) {
      float x=0,y=0;
      if (pass == 1) {
         points = STBTT_malloc(num_points * sizeof(points[0]), userdata);
         if (points == NULL) goto error;
      }
      num_points = 0;
      n= -1;
      for (i=0; i < num_verts; ++i) {
         switch (vertices[i].type) {
            case STBTT_vmove:
               // start the next contour
               if (n >= 0)
                  (*contour_lengths)[n] = num_points - start;
               ++n;
               start = num_points;
               x = vertices[i].x, y = vertices[i].y;
               stbtt__add_point(points, num_points++, x,y);
               break;
            case STBTT_vline:
               x = vertices[i].x, y = vertices[i].y;
               stbtt__add_point(points, num_points++, x, y);
               break;
            case STBTT_vcurve:
               stbtt__tesselate_curve(points, &num_points, x,y,
                                        vertices[i].cx, vertices[i].cy,
                                        vertices[i].x,  vertices[i].y,
                                        objspace_flatness_squared, 0);
               x = vertices[i].x, y = vertices[i].y;
               break;
            case STBTT_vcubic:
               stbtt__tesselate_cubic(points, &num_points, x,y,
                                        vertices[i].cx, vertices[i].cy,
                                        vertices[i].cx1, vertices[i].cy1,
                                        vertices[i].x,  vertices[i].y,
                                        objspace_flatness_squared, 0);
               x = vertices[i].x, y = vertices[i].y;
               break;
         }
      }
      (*contour_lengths)[n] = num_points - start;
   }
   return points;
error:
   STBTT_free(points, userdata);
   STBTT_free(*contour_lengths, userdata);
   *contour_lengths = 0;
   *num_contours = 0;
   return NULL;
}

// Rasterizes shape with quadratic beziers into a bitmap.
//
// @param result                  1-channel bitmap to draw into
// @param flatness_in_pixels      allowable error of curve in pixels
// @param vertices                array of vertices defining shape
// @param num_verts               number of vertices in above array
// @param scale_x scale_y         scale applied to input vertices
// @param shift_x shift_y         translation applied to input vertices
// @param x_off y_off             another translation applied to input
// @param invert                  if non-zero, vertically flip shape
// @param userdata                context for to STBTT_MALLOC
void stbtt_Rasterize(stbtt__bitmap *result, float flatness_in_pixels,
                     stbtt_vertex *vertices, int num_verts, float scale_x,
                     float scale_y, float shift_x, float shift_y, int x_off,
                     int y_off, int invert, void *userdata)
{
   float scale            = scale_x > scale_y ? scale_y : scale_x;
   int winding_count      = 0;
   int *winding_lengths   = NULL;
   stbtt__point *windings = stbtt_FlattenCurves(vertices, num_verts,
                                                flatness_in_pixels / scale,
                                                &winding_lengths,
                                                &winding_count, userdata);
   if (windings) {
      stbtt__rasterize(result, windings, winding_lengths, winding_count,
                       scale_x, scale_y, shift_x, shift_y, x_off, y_off,
                       invert, userdata);
      STBTT_free(winding_lengths, userdata);
      STBTT_free(windings, userdata);
   }
}

// frees the bitmap allocated below
void stbtt_FreeBitmap(unsigned char *bitmap, void *userdata)
{
   STBTT_free(bitmap, userdata);
}

unsigned char *stbtt_GetGlyphBitmapSubpixel(const stbtt_fontinfo *info,
                                            float scale_x, float scale_y,
                                            float shift_x, float shift_y,
                                            int glyph, int *width, int *height,
                                            int *xoff, int *yoff) {
   int ix0, iy0, ix1, iy1;
   stbtt__bitmap gbm;
   stbtt_vertex *vertices;
   int num_verts = stbtt_GetGlyphShape(info, glyph, &vertices);
   if (scale_x == 0) scale_x = scale_y;
   if (scale_y == 0) {
      if (scale_x == 0) {
         STBTT_free(vertices, info->userdata);
         return NULL;
      }
      scale_y = scale_x;
   }
   stbtt_GetGlyphBitmapBoxSubpixel(info, glyph, scale_x, scale_y, shift_x,
                                   shift_y, &ix0, &iy0, &ix1, &iy1);
   // now we get the size
   gbm.w = (ix1 - ix0);
   gbm.h = (iy1 - iy0);
   gbm.pixels = NULL;  // in case we error
   if (width) *width = gbm.w;
   if (height) *height = gbm.h;
   if (xoff) *xoff = ix0;
   if (yoff) *yoff = iy0;
   if (gbm.w && gbm.h) {
      gbm.pixels = STBTT_malloc(gbm.w * gbm.h, info->userdata);
      if (gbm.pixels) {
         gbm.stride = gbm.w;
         stbtt_Rasterize(&gbm, 0.35f, vertices, num_verts, scale_x, scale_y,
                         shift_x, shift_y, ix0, iy0, 1, info->userdata);
      }
   }
   STBTT_free(vertices, info->userdata);
   return gbm.pixels;
}

unsigned char *stbtt_GetGlyphBitmap(const stbtt_fontinfo *info, float scale_x,
                                    float scale_y, int glyph, int *width,
                                    int *height, int *xoff, int *yoff) {
   return stbtt_GetGlyphBitmapSubpixel(info, scale_x, scale_y, 0.0f, 0.0f, glyph,
                                       width, height, xoff, yoff);
}

void stbtt_MakeGlyphBitmapSubpixel(const stbtt_fontinfo *info,
                                   unsigned char *output, int out_w, int out_h,
                                   int out_stride, float scale_x, float scale_y,
                                   float shift_x, float shift_y, int glyph) {
   int ix0, iy0;
   stbtt_vertex *vertices;
   int num_verts = stbtt_GetGlyphShape(info, glyph, &vertices);
   stbtt__bitmap gbm;
   stbtt_GetGlyphBitmapBoxSubpixel(info, glyph, scale_x, scale_y, shift_x,
                                   shift_y, &ix0, &iy0, 0, 0);
   gbm.pixels = output;
   gbm.w = out_w;
   gbm.h = out_h;
   gbm.stride = out_stride;
   if (gbm.w && gbm.h)
      stbtt_Rasterize(&gbm, 0.35f, vertices, num_verts, scale_x, scale_y, shift_x,
                      shift_y, ix0, iy0, 1, info->userdata);
   STBTT_free(vertices, info->userdata);
}

void stbtt_MakeGlyphBitmap(const stbtt_fontinfo *info, unsigned char *output,
                           int out_w, int out_h, int out_stride, float scale_x,
                           float scale_y, int glyph) {
   stbtt_MakeGlyphBitmapSubpixel(info, output, out_w, out_h, out_stride, scale_x,
                                 scale_y, 0.0f, 0.0f, glyph);
}

// the same as stbtt_GetCodepoitnBitmap, but you can specify a subpixel
// shift for the character
void *stbtt_GetCodepointBitmapSubpixel(const stbtt_fontinfo *info,
                                       float scale_x, float scale_y,
                                       float shift_x, float shift_y,
                                       int codepoint, int *width,
                                       int *height, int *xoff,
                                       int *yoff) {
   return stbtt_GetGlyphBitmapSubpixel(info, scale_x, scale_y, shift_x, shift_y,
                                       stbtt_FindGlyphIndex(info, codepoint),
                                       width, height, xoff, yoff);
}

// same as stbtt_MakeCodepointBitmapSubpixel, but prefiltering
// is performed (see stbtt_PackSetOversampling)
void stbtt_MakeCodepointBitmapSubpixelPrefilter(
    const stbtt_fontinfo *info, unsigned char *output, int out_w, int out_h,
    int out_stride, float scale_x, float scale_y, float shift_x, float shift_y,
    int oversample_x, int oversample_y, float *sub_x, float *sub_y,
    int codepoint) {
   stbtt_MakeGlyphBitmapSubpixelPrefilter(
       info, output, out_w, out_h, out_stride, scale_x, scale_y, shift_x,
       shift_y, oversample_x, oversample_y, sub_x, sub_y,
       stbtt_FindGlyphIndex(info, codepoint));
}

// same as stbtt_MakeCodepointBitmap, but you can specify a subpixel
// shift for the character
void stbtt_MakeCodepointBitmapSubpixel(const stbtt_fontinfo *info,
                                       unsigned char *output, int out_w,
                                       int out_h, int out_stride, float scale_x,
                                       float scale_y, float shift_x,
                                       float shift_y, int codepoint) {
   stbtt_MakeGlyphBitmapSubpixel(info, output, out_w, out_h, out_stride, scale_x,
                                 scale_y, shift_x, shift_y,
                                 stbtt_FindGlyphIndex(info, codepoint));
}

// allocates a large-enough single-channel 8bpp bitmap and renders the
// specified character/glyph at the specified scale into it, with
// antialiasing. 0 is no coverage (transparent), 255 is fully covered (opaque).
// *width & *height are filled out with the width & height of the bitmap,
// which is stored left-to-right, top-to-bottom.
//
// xoff/yoff are the offset it pixel space from the glyph origin to the top-left
// of the bitmap
void *stbtt_GetCodepointBitmap(const stbtt_fontinfo *info,
                               float scale_x, float scale_y,
                               int codepoint, int *width, int *height,
                               int *xoff, int *yoff) {
   return stbtt_GetCodepointBitmapSubpixel(info, scale_x, scale_y, 0.0f, 0.0f,
                                           codepoint, width, height, xoff, yoff);
}

// the same as stbtt_GetCodepointBitmap, but you pass in storage for the bitmap
// in the form of 'output', with row spacing of 'out_stride' bytes. the bitmap
// is clipped to out_w/out_h bytes. Call stbtt_GetCodepointBitmapBox to get the
// width and height and positioning info for it first.
void stbtt_MakeCodepointBitmap(const stbtt_fontinfo *info,
                               unsigned char *output, int out_w, int out_h,
                               int out_stride, float scale_x, float scale_y,
                               int codepoint) {
   stbtt_MakeCodepointBitmapSubpixel(info, output, out_w, out_h, out_stride,
                                     scale_x, scale_y, 0.0f, 0.0f, codepoint);
}

//////////////////////////////////////////////////////////////////////////////
//
// bitmap baking
//
// This is SUPER-CRAPPY packing to keep source code small

// if return is positive, the first unused row of the bitmap
// if return is negative, returns the negative of the number of characters that fit
// if return is 0, no characters fit and no rows were used
// This uses a very crappy packing.
static int stbtt_BakeFontBitmap_internal(unsigned char *data, int offset,  // font location (use offset=0 for plain .ttf)
                                         float pixel_height,                     // height of font in pixels
                                         unsigned char *pixels, int pw, int ph,  // bitmap to be filled in
                                         int first_char, int num_chars,          // characters to bake
                                         stbtt_bakedchar *chardata)
{
   float scale;
   int x,y,bottom_y, i;
   stbtt_fontinfo f;
   f.userdata = NULL;
   if (!stbtt_InitFont(&f, data, offset))
      return -1;
   memset(pixels, 0, pw*ph); // background of 0 around pixels
   x=y=1;
   bottom_y = 1;
   scale = stbtt_ScaleForPixelHeight(&f, pixel_height);
   for (i=0; i < num_chars; ++i) {
      int advance, lsb, x0,y0,x1,y1,gw,gh;
      int g = stbtt_FindGlyphIndex(&f, first_char + i);
      stbtt_GetGlyphHMetrics(&f, g, &advance, &lsb);
      stbtt_GetGlyphBitmapBox(&f, g, scale,scale, &x0,&y0,&x1,&y1);
      gw = x1-x0;
      gh = y1-y0;
      if (x + gw + 1 >= pw)
         y = bottom_y, x = 1; // advance to next row
      if (y + gh + 1 >= ph) // check if it fits vertically AFTER potentially moving to next row
         return -i;
      ASSERT(x+gw < pw);
      ASSERT(y+gh < ph);
      stbtt_MakeGlyphBitmap(&f, pixels+x+y*pw, gw,gh,pw, scale,scale, g);
      chardata[i].x0 = (int16_t) x;
      chardata[i].y0 = (int16_t) y;
      chardata[i].x1 = (int16_t) (x + gw);
      chardata[i].y1 = (int16_t) (y + gh);
      chardata[i].xadvance = scale * advance;
      chardata[i].xoff     = (float) x0;
      chardata[i].yoff     = (float) y0;
      x = x + gw + 1;
      if (y+gh+1 > bottom_y)
         bottom_y = y+gh+1;
   }
   return bottom_y;
}

// Call GetBakedQuad with char_index = 'character - first_char', and it
// creates the quad you need to draw and advances the current position.
//
// The coordinate system used assumes y increases downwards.
//
// Characters will extend both above and below the current position;
// see discussion of "BASELINE" above.
//
// It's inefficient; you might want to c&p it and optimize it.
void stbtt_GetBakedQuad(const stbtt_bakedchar *chardata, int pw, int ph,
                        int char_index, float *xpos, float *ypos,
                        stbtt_aligned_quad *q, int opengl_fillrule)
{
   float d3d_bias = opengl_fillrule ? 0 : -0.5f;
   float ipw = 1.0f / pw, iph = 1.0f / ph;
   const stbtt_bakedchar *b = chardata + char_index;
   int round_x = STBTT_ifloor((*xpos + b->xoff) + 0.5f);
   int round_y = STBTT_ifloor((*ypos + b->yoff) + 0.5f);
   q->x0 = round_x + d3d_bias;
   q->y0 = round_y + d3d_bias;
   q->x1 = round_x + b->x1 - b->x0 + d3d_bias;
   q->y1 = round_y + b->y1 - b->y0 + d3d_bias;
   q->s0 = b->x0 * ipw;
   q->t0 = b->y0 * iph;
   q->s1 = b->x1 * ipw;
   q->t1 = b->y1 * iph;
   *xpos += b->xadvance;
}

//////////////////////////////////////////////////////////////////////////////
//
// bitmap baking
//
// This is SUPER-AWESOME (tm Ryan Gordon) packing using stb_rect_pack.h. If
// stb_rect_pack.h isn't available, it uses the BakeFontBitmap strategy.

// Initializes packing context stored in passed-in stbtt_pack_context.
// Future calls using this context will pack characters into the bitmap
// passed in here: a 1-channel bitmap that is width * height.
// stride_in_bytes is the distance from one row to the next (or 0 to
// mean they are packed tightly together). "padding" is the amount of
// padding to leave between each character (normally you want '1' for
// bitmaps you'll use as textures with bilinear filtering).
//
// Returns 0 on failure, 1 on success.
int stbtt_PackBegin(stbtt_pack_context *spc, unsigned char *pixels,
                    int pw, int ph, int stride_in_bytes, int padding,
                    void *alloc_context)
{
   stbrp_context *context = STBTT_malloc(sizeof(*context), alloc_context);
   int num_nodes = pw - padding;
   stbrp_node *nodes = STBTT_malloc(sizeof(*nodes) * num_nodes, alloc_context);
   if (!context || !nodes) {
      if (context) STBTT_free(context, alloc_context);
      if (nodes) STBTT_free(nodes, alloc_context);
      return 0;
   }
   spc->user_allocator_context = alloc_context;
   spc->width = pw;
   spc->height = ph;
   spc->pixels = pixels;
   spc->pack_info = context;
   spc->nodes = nodes;
   spc->padding = padding;
   spc->stride_in_bytes = stride_in_bytes != 0 ? stride_in_bytes : pw;
   spc->h_oversample = 1;
   spc->v_oversample = 1;
   spc->skip_missing = 0;
   stbrp_init_target(context, pw-padding, ph-padding, nodes, num_nodes);
   if (pixels)
      memset(pixels, 0, pw*ph); // background of 0 around pixels
   return 1;
}

// Cleans up the packing context and frees all memory.
void stbtt_PackEnd(stbtt_pack_context *spc)
{
   STBTT_free(spc->nodes    , spc->user_allocator_context);
   STBTT_free(spc->pack_info, spc->user_allocator_context);
}

// Oversampling a font increases the quality by allowing higher-quality subpixel
// positioning, and is especially valuable at smaller text sizes.
//
// This function sets the amount of oversampling for all following calls to
// stbtt_PackFontRange(s) or stbtt_PackFontRangesGatherRects for a given
// pack context. The default (no oversampling) is achieved by h_oversample=1
// and v_oversample=1. The total number of pixels required is
// h_oversample*v_oversample larger than the default; for example, 2x2
// oversampling requires 4x the storage of 1x1. For best results, render
// oversampled textures with bilinear filtering. Look at the readme in
// stb/tests/oversample for information about oversampled fonts
//
// To use with PackFontRangesGather etc., you must set it before calls
// call to PackFontRangesGatherRects.
void stbtt_PackSetOversampling(stbtt_pack_context *spc,
                               unsigned int h_oversample,
                               unsigned int v_oversample)
{
   ASSERT(h_oversample <= STBTT_MAX_OVERSAMPLE);
   ASSERT(v_oversample <= STBTT_MAX_OVERSAMPLE);
   if (h_oversample <= STBTT_MAX_OVERSAMPLE)
      spc->h_oversample = h_oversample;
   if (v_oversample <= STBTT_MAX_OVERSAMPLE)
      spc->v_oversample = v_oversample;
}

// If skip != 0, this tells stb_truetype to skip any codepoints for which
// there is no corresponding glyph. If skip=0, which is the default, then
// codepoints without a glyph recived the font's "missing character" glyph,
// typically an empty box by convention.
void stbtt_PackSetSkipMissingCodepoints(stbtt_pack_context *spc, int skip)
{
   spc->skip_missing = skip;
}

static void stbtt__h_prefilter(unsigned char *pixels, int w, int h,
                               int stride_in_bytes, unsigned int kernel_width)
{
   unsigned char buffer[STBTT_MAX_OVERSAMPLE];
   int safe_w = w - kernel_width;
   int j;
   memset(buffer, 0, STBTT_MAX_OVERSAMPLE); // suppress bogus warning from VS2013 -analyze
   for (j=0; j < h; ++j) {
      int i;
      unsigned int total = 0;
      memset(buffer, 0, kernel_width);
      // make kernel_width a constant in common cases so compiler can optimize out the divide
      switch (kernel_width) {
         case 2:
            for (i=0; i <= safe_w; ++i) {
               total += pixels[i] - buffer[i & STBTT__OVER_MASK];
               buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i];
               pixels[i] = total / 2;
            }
            break;
         case 3:
            for (i=0; i <= safe_w; ++i) {
               total += pixels[i] - buffer[i & STBTT__OVER_MASK];
               buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i];
               pixels[i] = total / 3;
            }
            break;
         case 4:
            for (i=0; i <= safe_w; ++i) {
               total += pixels[i] - buffer[i & STBTT__OVER_MASK];
               buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i];
               pixels[i] = total / 4;
            }
            break;
         case 5:
            for (i=0; i <= safe_w; ++i) {
               total += pixels[i] - buffer[i & STBTT__OVER_MASK];
               buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i];
               pixels[i] = total / 5;
            }
            break;
         default:
            for (i=0; i <= safe_w; ++i) {
               total += pixels[i] - buffer[i & STBTT__OVER_MASK];
               buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i];
               pixels[i] = total / kernel_width;
            }
            break;
      }
      for (; i < w; ++i) {
         ASSERT(pixels[i] == 0);
         total -= buffer[i & STBTT__OVER_MASK];
         pixels[i] = total / kernel_width;
      }
      pixels += stride_in_bytes;
   }
}

static void stbtt__v_prefilter(unsigned char *pixels, int w, int h,
                               int stride_in_bytes, unsigned int kernel_width)
{
   unsigned char buffer[STBTT_MAX_OVERSAMPLE];
   int safe_h = h - kernel_width;
   int j;
   memset(buffer, 0, STBTT_MAX_OVERSAMPLE); // suppress bogus warning from VS2013 -analyze
   for (j=0; j < w; ++j) {
      int i;
      unsigned int total;
      memset(buffer, 0, kernel_width);
      total = 0;
      // make kernel_width a constant in common cases so compiler can optimize out the divide
      switch (kernel_width) {
         case 2:
            for (i=0; i <= safe_h; ++i) {
               total += pixels[i*stride_in_bytes] - buffer[i & STBTT__OVER_MASK];
               buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i*stride_in_bytes];
               pixels[i*stride_in_bytes] = total / 2;
            }
            break;
         case 3:
            for (i=0; i <= safe_h; ++i) {
               total += pixels[i*stride_in_bytes] - buffer[i & STBTT__OVER_MASK];
               buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i*stride_in_bytes];
               pixels[i*stride_in_bytes] = total / 3;
            }
            break;
         case 4:
            for (i=0; i <= safe_h; ++i) {
               total += pixels[i*stride_in_bytes] - buffer[i & STBTT__OVER_MASK];
               buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i*stride_in_bytes];
               pixels[i*stride_in_bytes] = total / 4;
            }
            break;
         case 5:
            for (i=0; i <= safe_h; ++i) {
               total += pixels[i*stride_in_bytes] - buffer[i & STBTT__OVER_MASK];
               buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i*stride_in_bytes];
               pixels[i*stride_in_bytes] = total / 5;
            }
            break;
         default:
            for (i=0; i <= safe_h; ++i) {
               total += pixels[i*stride_in_bytes] - buffer[i & STBTT__OVER_MASK];
               buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i*stride_in_bytes];
               pixels[i*stride_in_bytes] = total / kernel_width;
            }
            break;
      }
      for (; i < h; ++i) {
         ASSERT(pixels[i*stride_in_bytes] == 0);
         total -= buffer[i & STBTT__OVER_MASK];
         pixels[i*stride_in_bytes] = total / kernel_width;
      }
      pixels += 1;
   }
}

static float stbtt__oversample_shift(int oversample)
{
   if (!oversample)
      return 0.0f;
   // The prefilter is a box filter of width "oversample",
   // which shifts phase by (oversample - 1)/2 pixels in
   // oversampled space. We want to shift in the opposite
   // direction to counter this.
   return (float)-(oversample - 1) / (2.0f * (float)oversample);
}

// Calling these functions
//
// - stbtt_PackFontRangesGatherRects
// - stbtt_PackFontRangesPackRects
// - stbtt_PackFontRangesRenderIntoRects
//
// in sequence is roughly equivalent to calling stbtt_PackFontRanges().
// If you more control over the packing of multiple fonts, or if you
// want to pack custom data into a font texture, take a look at the
// source to of stbtt_PackFontRanges() and create a custom version using
// these functions, e.g. call GatherRects multiple times, building up a
// single array of rects, then call PackRects once, then call
// RenderIntoRects repeatedly. This may result in a better packing than
// calling PackFontRanges multiple times (or it may not).
//
// rects array must be big enough to accommodate all characters in the given ranges
int stbtt_PackFontRangesGatherRects(stbtt_pack_context *spc,
                                    const stbtt_fontinfo *info,
                                    stbtt_pack_range *ranges,
                                    int num_ranges,
                                    stbrp_rect *rects)
{
   float fh,scale;
   int i,j,k,x0,y0,x1,y1,glyph,codepoint,missing_glyph_added;
   for (missing_glyph_added=k=i=0; i < num_ranges; ++i) {
      if ((fh = ranges[i].font_size) > 0) {
         scale = stbtt_ScaleForPixelHeight(info, fh);
      } else {
         scale = stbtt_ScaleForMappingEmToPixels(info, -fh);
      }
      ranges[i].h_oversample = spc->h_oversample;
      ranges[i].v_oversample = spc->v_oversample;
      for (j=0; j < ranges[i].num_chars; ++j) {
         if (!ranges[i].array_of_unicode_codepoints) {
            codepoint = ranges[i].first_unicode_codepoint_in_range + j;
         } else {
            codepoint = ranges[i].array_of_unicode_codepoints[j];
         }
         glyph = stbtt_FindGlyphIndex(info, codepoint);
         if (glyph == 0 && (spc->skip_missing || missing_glyph_added)) {
            rects[k].w = rects[k].h = 0;
         } else {
            stbtt_GetGlyphBitmapBoxSubpixel(info,glyph,
                                            scale * spc->h_oversample,
                                            scale * spc->v_oversample,
                                            0,0,
                                            &x0,&y0,&x1,&y1);
            rects[k].w = x1-x0 + spc->padding + spc->h_oversample-1;
            rects[k].h = y1-y0 + spc->padding + spc->v_oversample-1;
            if (glyph == 0)
               missing_glyph_added = 1;
         }
         ++k;
      }
   }
   return k;
}

void stbtt_MakeGlyphBitmapSubpixelPrefilter(const stbtt_fontinfo *info,
                                            unsigned char *output,
                                            int out_w, int out_h,
                                            int out_stride,
                                            float scale_x, float scale_y,
                                            float shift_x, float shift_y,
                                            int prefilter_x, int prefilter_y,
                                            float *sub_x, float *sub_y,
                                            int glyph)
{
   stbtt_MakeGlyphBitmapSubpixel(info,
                                 output,
                                 out_w - (prefilter_x - 1),
                                 out_h - (prefilter_y - 1),
                                 out_stride,
                                 scale_x,
                                 scale_y,
                                 shift_x,
                                 shift_y,
                                 glyph);
   if (prefilter_x > 1)
      stbtt__h_prefilter(output, out_w, out_h, out_stride, prefilter_x);
   if (prefilter_y > 1)
      stbtt__v_prefilter(output, out_w, out_h, out_stride, prefilter_y);
   *sub_x = stbtt__oversample_shift(prefilter_x);
   *sub_y = stbtt__oversample_shift(prefilter_y);
}

// Calling these functions
//
// - stbtt_PackFontRangesGatherRects
// - stbtt_PackFontRangesPackRects
// - stbtt_PackFontRangesRenderIntoRects
//
// in sequence is roughly equivalent to calling stbtt_PackFontRanges().
// If you more control over the packing of multiple fonts, or if you
// want to pack custom data into a font texture, take a look at the
// source to of stbtt_PackFontRanges() and create a custom version using
// these functions, e.g. call GatherRects multiple times, building up a
// single array of rects, then call PackRects once, then call
// RenderIntoRects repeatedly. This may result in a better packing than
// calling PackFontRanges multiple times (or it may not).
//
// rects array must be big enough to accommodate all characters in the given ranges
int stbtt_PackFontRangesRenderIntoRects(stbtt_pack_context *spc,
                                        const stbtt_fontinfo *info,
                                        stbtt_pack_range *ranges,
                                        int num_ranges, stbrp_rect *rects)
{
   int i,j,k, missing_glyph = -1, return_value = 1;
   // save current values
   int old_h_over = spc->h_oversample;
   int old_v_over = spc->v_oversample;
   k = 0;
   for (i=0; i < num_ranges; ++i) {
      float fh = ranges[i].font_size;
      float scale = fh > 0 ? stbtt_ScaleForPixelHeight(info, fh) : stbtt_ScaleForMappingEmToPixels(info, -fh);
      float recip_h,recip_v,sub_x,sub_y;
      spc->h_oversample = ranges[i].h_oversample;
      spc->v_oversample = ranges[i].v_oversample;
      recip_h = 1.0f / spc->h_oversample;
      recip_v = 1.0f / spc->v_oversample;
      sub_x = stbtt__oversample_shift(spc->h_oversample);
      sub_y = stbtt__oversample_shift(spc->v_oversample);
      for (j=0; j < ranges[i].num_chars; ++j) {
         stbrp_rect *r = &rects[k];
         if (r->was_packed && r->w != 0 && r->h != 0) {
            stbtt_packedchar *bc = &ranges[i].chardata_for_range[j];
            int advance, lsb, x0,y0,x1,y1;
            int codepoint = ranges[i].array_of_unicode_codepoints == NULL ? ranges[i].first_unicode_codepoint_in_range + j : ranges[i].array_of_unicode_codepoints[j];
            int glyph = stbtt_FindGlyphIndex(info, codepoint);
            stbrp_coord pad = (stbrp_coord) spc->padding;
            // pad on left and top
            r->x += pad;
            r->y += pad;
            r->w -= pad;
            r->h -= pad;
            stbtt_GetGlyphHMetrics(info, glyph, &advance, &lsb);
            stbtt_GetGlyphBitmapBox(info, glyph,
                                    scale * spc->h_oversample,
                                    scale * spc->v_oversample,
                                    &x0,&y0,&x1,&y1);
            stbtt_MakeGlyphBitmapSubpixel(info,
                                          spc->pixels + r->x + r->y*spc->stride_in_bytes,
                                          r->w - spc->h_oversample+1,
                                          r->h - spc->v_oversample+1,
                                          spc->stride_in_bytes,
                                          scale * spc->h_oversample,
                                          scale * spc->v_oversample,
                                          0,0,
                                          glyph);
            if (spc->h_oversample > 1)
               stbtt__h_prefilter(spc->pixels + r->x + r->y*spc->stride_in_bytes,
                                  r->w, r->h, spc->stride_in_bytes,
                                  spc->h_oversample);
            if (spc->v_oversample > 1)
               stbtt__v_prefilter(spc->pixels + r->x + r->y*spc->stride_in_bytes,
                                  r->w, r->h, spc->stride_in_bytes,
                                  spc->v_oversample);
            bc->x0       = (int16_t)  r->x;
            bc->y0       = (int16_t)  r->y;
            bc->x1       = (int16_t) (r->x + r->w);
            bc->y1       = (int16_t) (r->y + r->h);
            bc->xadvance =                scale * advance;
            bc->xoff     =       (float)  x0 * recip_h + sub_x;
            bc->yoff     =       (float)  y0 * recip_v + sub_y;
            bc->xoff2    =                (x0 + r->w) * recip_h + sub_x;
            bc->yoff2    =                (y0 + r->h) * recip_v + sub_y;
            if (glyph == 0)
               missing_glyph = j;
         } else if (spc->skip_missing) {
            return_value = 0;
         } else if (r->was_packed && r->w == 0 && r->h == 0 && missing_glyph >= 0) {
            ranges[i].chardata_for_range[j] = ranges[i].chardata_for_range[missing_glyph];
         } else {
            return_value = 0; // if any fail, report failure
         }
         ++k;
      }
   }
   // restore original values
   spc->h_oversample = old_h_over;
   spc->v_oversample = old_v_over;
   return return_value;
}

void stbtt_PackFontRangesPackRects(stbtt_pack_context *spc, stbrp_rect *rects, int num_rects)
{
   stbrp_pack_rects((stbrp_context *) spc->pack_info, rects, num_rects);
}

// Creates character bitmaps from multiple ranges of characters stored in
// ranges. This will usually create a better-packed bitmap than multiple
// calls to stbtt_PackFontRange. Note that you can call this multiple
// times within a single PackBegin/PackEnd.
int stbtt_PackFontRanges(stbtt_pack_context *spc, const unsigned char *fontdata,
                         int font_index, stbtt_pack_range *ranges,
                         int num_ranges)
{
   stbtt_fontinfo info;
   int i,j,n, return_value = 1;
   //stbrp_context *context = (stbrp_context *) spc->pack_info;
   stbrp_rect    *rects;
   // flag all characters as NOT packed
   for (i=0; i < num_ranges; ++i)
      for (j=0; j < ranges[i].num_chars; ++j)
         ranges[i].chardata_for_range[j].x0 =
         ranges[i].chardata_for_range[j].y0 =
         ranges[i].chardata_for_range[j].x1 =
         ranges[i].chardata_for_range[j].y1 = 0;
   n = 0;
   for (i=0; i < num_ranges; ++i)
      n += ranges[i].num_chars;
   rects = STBTT_malloc(sizeof(*rects) * n, spc->user_allocator_context);
   if (rects == NULL)
      return 0;
   info.userdata = spc->user_allocator_context;
   stbtt_InitFont(&info, fontdata, stbtt_GetFontOffsetForIndex(fontdata,font_index));
   n = stbtt_PackFontRangesGatherRects(spc, &info, ranges, num_ranges, rects);
   stbtt_PackFontRangesPackRects(spc, rects, n);
   return_value = stbtt_PackFontRangesRenderIntoRects(spc, &info, ranges, num_ranges, rects);
   STBTT_free(rects, spc->user_allocator_context);
   return return_value;
}

// Creates character bitmaps from the font_index'th font found in fontdata (use
// font_index=0 if you don't know what that is). It creates num_chars_in_range
// bitmaps for characters with unicode values starting at first_unicode_char_in_range
// and increasing. Data for how to render them is stored in chardata_for_range;
// pass these to stbtt_GetPackedQuad to get back renderable quads.
//
// font_size is the full height of the character from ascender to descender,
// as computed by stbtt_ScaleForPixelHeight. To use a point size as computed
// by stbtt_ScaleForMappingEmToPixels, wrap the point size in STBTT_POINT_SIZE()
// and pass that result as 'font_size':
//       ...,                  20 , ... // font max minus min y is 20 pixels tall
//       ..., STBTT_POINT_SIZE(20), ... // 'M' is 20 pixels tall
int stbtt_PackFontRange(stbtt_pack_context *spc,
                                  const unsigned char *fontdata,
                                  int font_index, float font_size,
                                  int first_unicode_codepoint_in_range,
                                  int num_chars_in_range,
                                  stbtt_packedchar *chardata_for_range)
{
   stbtt_pack_range range;
   range.first_unicode_codepoint_in_range = first_unicode_codepoint_in_range;
   range.array_of_unicode_codepoints = NULL;
   range.num_chars                   = num_chars_in_range;
   range.chardata_for_range          = chardata_for_range;
   range.font_size                   = font_size;
   return stbtt_PackFontRanges(spc, fontdata, font_index, &range, 1);
}

// Query the font vertical metrics without having to create a font first.
void stbtt_GetScaledFontVMetrics(const unsigned char *fontdata, int index,
                                 float size, float *ascent, float *descent,
                                 float *lineGap)
{
   float scale;
   stbtt_fontinfo info;
   int i_ascent, i_descent, i_lineGap;
   stbtt_InitFont(&info, fontdata, stbtt_GetFontOffsetForIndex(fontdata, index));
   scale = size > 0 ? stbtt_ScaleForPixelHeight(&info, size) : stbtt_ScaleForMappingEmToPixels(&info, -size);
   stbtt_GetFontVMetrics(&info, &i_ascent, &i_descent, &i_lineGap);
   *ascent  = i_ascent  * scale;
   *descent = i_descent * scale;
   *lineGap = i_lineGap * scale;
}

void stbtt_GetPackedQuad(const stbtt_packedchar *chardata, int pw, int ph,
                         int char_index, float *xpos, float *ypos,
                         stbtt_aligned_quad *q, int align_to_integer)
{
   float ipw = 1.0f / pw, iph = 1.0f / ph;
   const stbtt_packedchar *b = chardata + char_index;
   if (align_to_integer) {
      float x = STBTT_ifloor((*xpos + b->xoff) + .5f);
      float y = STBTT_ifloor((*ypos + b->yoff) + .5f);
      q->x0 = x;
      q->y0 = y;
      q->x1 = x + b->xoff2 - b->xoff;
      q->y1 = y + b->yoff2 - b->yoff;
   } else {
      q->x0 = *xpos + b->xoff;
      q->y0 = *ypos + b->yoff;
      q->x1 = *xpos + b->xoff2;
      q->y1 = *ypos + b->yoff2;
   }
   q->s0 = b->x0 * ipw;
   q->t0 = b->y0 * iph;
   q->s1 = b->x1 * ipw;
   q->t1 = b->y1 * iph;
   *xpos += b->xadvance;
}

//////////////////////////////////////////////////////////////////////////////
//
// sdf computation
//

static int stbtt__ray_intersect_bezier(float orig[2], float ray[2], float q0[2],
                                       float q1[2], float q2[2],
                                       float hits[2][2])
{
   float q0perp = q0[1]*ray[0] - q0[0]*ray[1];
   float q1perp = q1[1]*ray[0] - q1[0]*ray[1];
   float q2perp = q2[1]*ray[0] - q2[0]*ray[1];
   float roperp = orig[1]*ray[0] - orig[0]*ray[1];
   float a = q0perp - 2*q1perp + q2perp;
   float b = q1perp - q0perp;
   float c = q0perp - roperp;
   float s0 = 0., s1 = 0.;
   int num_s = 0;
   if (a != 0.0) {
      float discr = b*b - a*c;
      if (discr > 0.0) {
         float rcpna = -1 / a;
         float d = (float) sqrt(discr);
         s0 = (b+d) * rcpna;
         s1 = (b-d) * rcpna;
         if (s0 >= 0.0 && s0 <= 1.0)
            num_s = 1;
         if (d > 0.0 && s1 >= 0.0 && s1 <= 1.0) {
            if (num_s == 0) s0 = s1;
            ++num_s;
         }
      }
   } else {
      // 2*b*s + c = 0
      // s = -c / (2*b)
      s0 = c / (-2 * b);
      if (s0 >= 0.0 && s0 <= 1.0)
         num_s = 1;
   }
   if (num_s == 0)
      return 0;
   else {
      float rcp_len2 = 1 / (ray[0]*ray[0] + ray[1]*ray[1]);
      float rayn_x = ray[0] * rcp_len2, rayn_y = ray[1] * rcp_len2;
      float q0d =   q0[0]*rayn_x +   q0[1]*rayn_y;
      float q1d =   q1[0]*rayn_x +   q1[1]*rayn_y;
      float q2d =   q2[0]*rayn_x +   q2[1]*rayn_y;
      float rod = orig[0]*rayn_x + orig[1]*rayn_y;
      float q10d = q1d - q0d;
      float q20d = q2d - q0d;
      float q0rd = q0d - rod;
      hits[0][0] = q0rd + s0*(2.0f - 2.0f*s0)*q10d + s0*s0*q20d;
      hits[0][1] = a*s0+b;
      if (num_s > 1) {
         hits[1][0] = q0rd + s1*(2.0f - 2.0f*s1)*q10d + s1*s1*q20d;
         hits[1][1] = a*s1+b;
         return 2;
      } else {
         return 1;
      }
   }
}

static int equal(float *a, float *b)
{
   return (a[0] == b[0] && a[1] == b[1]);
}

static int stbtt__compute_crossings_x(float x, float y, int nverts,
                                      stbtt_vertex *verts)
{
   int i;
   float orig[2], ray[2] = { 1, 0 };
   float y_frac;
   int winding = 0;
   // make sure y never passes through a vertex of the shape
   y_frac = (float) fmod(y, 1.0f);
   if (y_frac < 0.01f) {
      y += 0.01f;
   } else if (y_frac > 0.99f) {
      y -= 0.01f;
   }
   orig[0] = x;
   orig[1] = y;
   // test a ray from (-infinity,y) to (x,y)
   for (i=0; i < nverts; ++i) {
      if (verts[i].type == STBTT_vline) {
         int x0 = (int) verts[i-1].x, y0 = (int) verts[i-1].y;
         int x1 = (int) verts[i  ].x, y1 = (int) verts[i  ].y;
         if (y > MIN(y0,y1) && y < MAX(y0,y1) && x > MIN(x0,x1)) {
            float x_inter = (y - y0) / (y1 - y0) * (x1-x0) + x0;
            if (x_inter < x)
               winding += (y0 < y1) ? 1 : -1;
         }
      }
      if (verts[i].type == STBTT_vcurve) {
         int x0 = (int) verts[i-1].x , y0 = (int) verts[i-1].y ;
         int x1 = (int) verts[i  ].cx, y1 = (int) verts[i  ].cy;
         int x2 = (int) verts[i  ].x , y2 = (int) verts[i  ].y ;
         int ax = MIN(x0,MIN(x1,x2)), ay = MIN(y0,MIN(y1,y2));
         int by = MAX(y0,MAX(y1,y2));
         if (y > ay && y < by && x > ax) {
            float q0[2],q1[2],q2[2];
            float hits[2][2];
            q0[0] = (float)x0;
            q0[1] = (float)y0;
            q1[0] = (float)x1;
            q1[1] = (float)y1;
            q2[0] = (float)x2;
            q2[1] = (float)y2;
            if (equal(q0,q1) || equal(q1,q2)) {
               x0 = (int)verts[i-1].x;
               y0 = (int)verts[i-1].y;
               x1 = (int)verts[i  ].x;
               y1 = (int)verts[i  ].y;
               if (y > MIN(y0,y1) && y < MAX(y0,y1) && x > MIN(x0,x1)) {
                  float x_inter = (y - y0) / (y1 - y0) * (x1-x0) + x0;
                  if (x_inter < x)
                     winding += (y0 < y1) ? 1 : -1;
               }
            } else {
               int num_hits = stbtt__ray_intersect_bezier(orig, ray, q0, q1, q2, hits);
               if (num_hits >= 1)
                  if (hits[0][0] < 0)
                     winding += (hits[0][1] < 0 ? -1 : 1);
               if (num_hits >= 2)
                  if (hits[1][0] < 0)
                     winding += (hits[1][1] < 0 ? -1 : 1);
            }
         }
      }
   }
   return winding;
}

static float stbtt__cuberoot( float x )
{
   if (x<0)
      return -powf(-x,1.0f/3.0f);
   else
      return  powf( x,1.0f/3.0f);
}

// x^3 + a*x^2 + b*x + c = 0
static int stbtt__solve_cubic(float a, float b, float c, float* r)
{
   float s = -a / 3;
   float p = b - a*a / 3;
   float q = a * (2*a*a - 9*b) / 27 + c;
   float p3 = p*p*p;
   float d = q*q + 4*p3 / 27;
   if (d >= 0) {
      float z = sqrtf(d);
      float u = (-q + z) / 2;
      float v = (-q - z) / 2;
      u = stbtt__cuberoot(u);
      v = stbtt__cuberoot(v);
      r[0] = s + u + v;
      return 1;
   } else {
      float u = sqrtf(-p/3);
      float v = acos(-sqrt(-27/p3) * q / 2) / 3; // p3 must be negative, since d is negative
      float m = cos(v);
      float n = cos(v-3.141592/2)*1.732050808f;
      r[0] = s + u * 2 * m;
      r[1] = s - u * (m + n);
      r[2] = s - u * (m - n);
      // these asserts may not be safe at all scales
      // though they're in bezier t parameter units so maybe?
      //ASSERT( fabs(((r[0]+a)*r[0]+b)*r[0]+c) < 0.05f);
      //ASSERT( fabs(((r[1]+a)*r[1]+b)*r[1]+c) < 0.05f);
      //ASSERT( fabs(((r[2]+a)*r[2]+b)*r[2]+c) < 0.05f);
      return 3;
   }
}

// This and stbtt_GetCodepointSDF() compute a discretized SDF field for
// a single character, suitable for storing in a single-channel texture,
// sampling with bilinear filtering, and testing against larger than
// some threshold to produce scalable fonts.
//
//        info              --  the font
//        scale             --  controls the size of the resulting SDF bitmap, same as it would be creating a regular bitmap
//        glyph/codepoint   --  the character to generate the SDF for
//        padding           --  extra "pixels" around the character which are filled with the distance to the character (not 0),
//                                 which allows effects like bit outlines
//        onedge_value      --  value 0-255 to test the SDF against to reconstruct the character (i.e. the isocontour of the character)
//        pixel_dist_scale  --  what value the SDF should increase by when moving one SDF "pixel" away from the edge (on the 0..255 scale)
//                                 if positive, > onedge_value is inside; if negative, < onedge_value is inside
//        width,height      --  output height & width of the SDF bitmap (including padding)
//        xoff,yoff         --  output origin of the character
//        return value      --  a 2D array of bytes 0..255, width*height in size
//
// pixel_dist_scale & onedge_value are a scale & bias that allows you to make
// optimal use of the limited 0..255 for your application, trading off precision
// and special effects. SDF values outside the range 0..255 are clamped to 0..255.
//
// Example:
//      scale = stbtt_ScaleForPixelHeight(22)
//      padding = 5
//      onedge_value = 180
//      pixel_dist_scale = 180/5.0 = 36.0
//
//      This will create an SDF bitmap in which the character is about 22 pixels
//      high but the whole bitmap is about 22+5+5=32 pixels high. To produce a filled
//      shape, sample the SDF at each pixel and fill the pixel if the SDF value
//      is greater than or equal to 180/255. (You'll actually want to antialias,
//      which is beyond the scope of this example.) Additionally, you can compute
//      offset outlines (e.g. to stroke the character border inside & outside,
//      or only outside). For example, to fill outside the character up to 3 SDF
//      pixels, you would compare against (180-36.0*3)/255 = 72/255. The above
//      choice of variables maps a range from 5 pixels outside the shape to
//      2 pixels inside the shape to 0..255; this is intended primarily for apply
//      outside effects only (the interior range is needed to allow proper
//      antialiasing of the font at *smaller* sizes)
//
// The function computes the SDF analytically at each SDF pixel, not by e.g.
// building a higher-res bitmap and approximating it. In theory the quality
// should be as high as possible for an SDF of this size & representation, but
// unclear if this is true in practice (perhaps building a higher-res bitmap
// and computing from that can allow drop-out prevention).
//
// The algorithm has not been optimized at all, so expect it to be slow
// if computing lots of characters or very large sizes.
unsigned char * stbtt_GetGlyphSDF(const stbtt_fontinfo *info, float scale,
                                  int glyph, int padding,
                                  unsigned char onedge_value,
                                  float pixel_dist_scale,
                                  int *width, int *height,
                                  int *xoff, int *yoff)
{
   float scale_x = scale, scale_y = scale;
   int ix0,iy0,ix1,iy1;
   int w,h;
   unsigned char *data;
   if (scale == 0) return NULL;
   stbtt_GetGlyphBitmapBoxSubpixel(info, glyph, scale, scale, 0.0f,0.0f, &ix0,&iy0,&ix1,&iy1);
   // if empty, return NULL
   if (ix0 == ix1 || iy0 == iy1)
      return NULL;
   ix0 -= padding;
   iy0 -= padding;
   ix1 += padding;
   iy1 += padding;
   w = (ix1 - ix0);
   h = (iy1 - iy0);
   if (width ) *width  = w;
   if (height) *height = h;
   if (xoff  ) *xoff   = ix0;
   if (yoff  ) *yoff   = iy0;
   // invert for y-downwards bitmaps
   scale_y = -scale_y;
   {
      int x,y,i,j;
      float *precompute;
      stbtt_vertex *verts;
      int num_verts = stbtt_GetGlyphShape(info, glyph, &verts);
      data = STBTT_malloc(w * h, info->userdata);
      precompute = STBTT_malloc(num_verts * sizeof(float), info->userdata);
      for (i=0,j=num_verts-1; i < num_verts; j=i++) {
         if (verts[i].type == STBTT_vline) {
            float x0 = verts[i].x*scale_x, y0 = verts[i].y*scale_y;
            float x1 = verts[j].x*scale_x, y1 = verts[j].y*scale_y;
            float dist = (float) sqrt((x1-x0)*(x1-x0) + (y1-y0)*(y1-y0));
            precompute[i] = (dist == 0) ? 0.0f : 1.0f / dist;
         } else if (verts[i].type == STBTT_vcurve) {
            float x2 = verts[j].x *scale_x, y2 = verts[j].y *scale_y;
            float x1 = verts[i].cx*scale_x, y1 = verts[i].cy*scale_y;
            float x0 = verts[i].x *scale_x, y0 = verts[i].y *scale_y;
            float bx = x0 - 2*x1 + x2, by = y0 - 2*y1 + y2;
            float len2 = bx*bx + by*by;
            if (len2 != 0.0f)
               precompute[i] = 1.0f / (bx*bx + by*by);
            else
               precompute[i] = 0.0f;
         } else
            precompute[i] = 0.0f;
      }
      for (y=iy0; y < iy1; ++y) {
         for (x=ix0; x < ix1; ++x) {
            float val;
            float min_dist = 999999.0f;
            float sx = (float) x + 0.5f;
            float sy = (float) y + 0.5f;
            float x_gspace = (sx / scale_x);
            float y_gspace = (sy / scale_y);
            int winding = stbtt__compute_crossings_x(x_gspace, y_gspace, num_verts, verts); // @OPTIMIZE: this could just be a rasterization, but needs to be line vs. non-tesselated curves so a new path
            for (i=0; i < num_verts; ++i) {
               float x0 = verts[i].x*scale_x, y0 = verts[i].y*scale_y;
               if (verts[i].type == STBTT_vline && precompute[i] != 0.0f) {
                  float x1 = verts[i-1].x*scale_x, y1 = verts[i-1].y*scale_y;
                  float dist,dist2 = (x0-sx)*(x0-sx) + (y0-sy)*(y0-sy);
                  if (dist2 < min_dist*min_dist)
                     min_dist = (float) sqrt(dist2);
                  // coarse culling against bbox
                  //if (sx > MIN(x0,x1)-min_dist && sx < MAX(x0,x1)+min_dist &&
                  //    sy > MIN(y0,y1)-min_dist && sy < MAX(y0,y1)+min_dist)
                  dist = (float) fabs((x1-x0)*(y0-sy) - (y1-y0)*(x0-sx)) * precompute[i];
                  ASSERT(i != 0);
                  if (dist < min_dist) {
                     // check position along line
                     // x' = x0 + t*(x1-x0), y' = y0 + t*(y1-y0)
                     // minimize (x'-sx)*(x'-sx)+(y'-sy)*(y'-sy)
                     float dx = x1-x0, dy = y1-y0;
                     float px = x0-sx, py = y0-sy;
                     // minimize (px+t*dx)^2 + (py+t*dy)^2 = px*px + 2*px*dx*t + t^2*dx*dx + py*py + 2*py*dy*t + t^2*dy*dy
                     // derivative: 2*px*dx + 2*py*dy + (2*dx*dx+2*dy*dy)*t, set to 0 and solve
                     float t = -(px*dx + py*dy) / (dx*dx + dy*dy);
                     if (t >= 0.0f && t <= 1.0f)
                        min_dist = dist;
                  }
               } else if (verts[i].type == STBTT_vcurve) {
                  float x2 = verts[i-1].x *scale_x, y2 = verts[i-1].y *scale_y;
                  float x1 = verts[i  ].cx*scale_x, y1 = verts[i  ].cy*scale_y;
                  float box_x0 = MIN(MIN(x0,x1),x2);
                  float box_y0 = MIN(MIN(y0,y1),y2);
                  float box_x1 = MAX(MAX(x0,x1),x2);
                  float box_y1 = MAX(MAX(y0,y1),y2);
                  // coarse culling against bbox to avoid computing cubic unnecessarily
                  if (sx > box_x0-min_dist && sx < box_x1+min_dist && sy > box_y0-min_dist && sy < box_y1+min_dist) {
                     int num=0;
                     float ax = x1-x0, ay = y1-y0;
                     float bx = x0 - 2*x1 + x2, by = y0 - 2*y1 + y2;
                     float mx = x0 - sx, my = y0 - sy;
                     float res[3] = {0.f,0.f,0.f};
                     float px,py,t,it,dist2;
                     float a_inv = precompute[i];
                     if (a_inv == 0.0) { // if a_inv is 0, it's 2nd degree so use quadratic formula
                        float a = 3*(ax*bx + ay*by);
                        float b = 2*(ax*ax + ay*ay) + (mx*bx+my*by);
                        float c = mx*ax+my*ay;
                        if (a == 0.0) { // if a is 0, it's linear
                           if (b != 0.0) {
                              res[num++] = -c/b;
                           }
                        } else {
                           float discriminant = b*b - 4*a*c;
                           if (discriminant < 0)
                              num = 0;
                           else {
                              float root = (float) sqrt(discriminant);
                              res[0] = (-b - root)/(2*a);
                              res[1] = (-b + root)/(2*a);
                              num = 2; // don't bother distinguishing 1-solution case, as code below will still work
                           }
                        }
                     } else {
                        float b = 3*(ax*bx + ay*by) * a_inv; // could precompute this as it doesn't depend on sample point
                        float c = (2*(ax*ax + ay*ay) + (mx*bx+my*by)) * a_inv;
                        float d = (mx*ax+my*ay) * a_inv;
                        num = stbtt__solve_cubic(b, c, d, res);
                     }
                     dist2 = (x0-sx)*(x0-sx) + (y0-sy)*(y0-sy);
                     if (dist2 < min_dist*min_dist)
                        min_dist = (float) sqrt(dist2);
                     if (num >= 1 && res[0] >= 0.0f && res[0] <= 1.0f) {
                        t = res[0], it = 1.0f - t;
                        px = it*it*x0 + 2*t*it*x1 + t*t*x2;
                        py = it*it*y0 + 2*t*it*y1 + t*t*y2;
                        dist2 = (px-sx)*(px-sx) + (py-sy)*(py-sy);
                        if (dist2 < min_dist * min_dist)
                           min_dist = (float) sqrt(dist2);
                     }
                     if (num >= 2 && res[1] >= 0.0f && res[1] <= 1.0f) {
                        t = res[1], it = 1.0f - t;
                        px = it*it*x0 + 2*t*it*x1 + t*t*x2;
                        py = it*it*y0 + 2*t*it*y1 + t*t*y2;
                        dist2 = (px-sx)*(px-sx) + (py-sy)*(py-sy);
                        if (dist2 < min_dist * min_dist)
                           min_dist = (float) sqrt(dist2);
                     }
                     if (num >= 3 && res[2] >= 0.0f && res[2] <= 1.0f) {
                        t = res[2], it = 1.0f - t;
                        px = it*it*x0 + 2*t*it*x1 + t*t*x2;
                        py = it*it*y0 + 2*t*it*y1 + t*t*y2;
                        dist2 = (px-sx)*(px-sx) + (py-sy)*(py-sy);
                        if (dist2 < min_dist * min_dist)
                           min_dist = (float) sqrt(dist2);
                     }
                  }
               }
            }
            if (winding == 0)
               min_dist = -min_dist;  // if outside the shape, value is negative
            val = onedge_value + pixel_dist_scale * min_dist;
            if (val < 0)
               val = 0;
            else if (val > 255)
               val = 255;
            data[(y-iy0)*w+(x-ix0)] = (unsigned char) val;
         }
      }
      STBTT_free(precompute, info->userdata);
      STBTT_free(verts, info->userdata);
   }
   return data;
}

unsigned char *stbtt_GetCodepointSDF(const stbtt_fontinfo *info, float scale,
                                     int codepoint, int padding,
                                     unsigned char onedge_value,
                                     float pixel_dist_scale,
                                     int *width, int *height,
                                     int *xoff, int *yoff)
{
   return stbtt_GetGlyphSDF(info, scale, stbtt_FindGlyphIndex(info, codepoint),
                            padding, onedge_value, pixel_dist_scale, width, height,
                            xoff, yoff);
}

// Frees Signed Distance Function bitmap.
void stbtt_FreeSDF(unsigned char *bitmap, void *userdata)
{
   STBTT_free(bitmap, userdata);
}

//////////////////////////////////////////////////////////////////////////////
//
// font name matching -- recommended not to use this
//

// check if a utf8 string contains a prefix which is the utf16 string; if so return length of matching utf8 string
static int32_t stbtt__CompareUTF8toUTF16_bigendian_prefix(uint8_t *s1, int32_t len1, uint8_t *s2, int32_t len2)
{
   int32_t i=0;
   // convert utf16 to utf8 and compare the results while converting
   while (len2) {
      uint16_t ch = s2[0]*256 + s2[1];
      if (ch < 0x80) {
         if (i >= len1) return -1;
         if (s1[i++] != ch) return -1;
      } else if (ch < 0x800) {
         if (i+1 >= len1) return -1;
         if (s1[i++] != 0xc0 + (ch >> 6)) return -1;
         if (s1[i++] != 0x80 + (ch & 0x3f)) return -1;
      } else if (ch >= 0xd800 && ch < 0xdc00) {
         uint32_t c;
         uint16_t ch2 = s2[2]*256 + s2[3];
         if (i+3 >= len1) return -1;
         c = ((ch - 0xd800) << 10) + (ch2 - 0xdc00) + 0x10000;
         if (s1[i++] != 0xf0 + (c >> 18)) return -1;
         if (s1[i++] != 0x80 + ((c >> 12) & 0x3f)) return -1;
         if (s1[i++] != 0x80 + ((c >>  6) & 0x3f)) return -1;
         if (s1[i++] != 0x80 + ((c      ) & 0x3f)) return -1;
         s2 += 2; // plus another 2 below
         len2 -= 2;
      } else if (ch >= 0xdc00 && ch < 0xe000) {
         return -1;
      } else {
         if (i+2 >= len1) return -1;
         if (s1[i++] != 0xe0 + (ch >> 12)) return -1;
         if (s1[i++] != 0x80 + ((ch >> 6) & 0x3f)) return -1;
         if (s1[i++] != 0x80 + ((ch     ) & 0x3f)) return -1;
      }
      s2 += 2;
      len2 -= 2;
   }
   return i;
}

static int stbtt_CompareUTF8toUTF16_bigendian_internal(char *s1, int len1, char *s2, int len2)
{
   return len1 == stbtt__CompareUTF8toUTF16_bigendian_prefix((uint8_t*) s1, len1, (uint8_t*) s2, len2);
}

// Returns the string (which may be big-endian double byte, e.g. for unicode)
// and puts the length in bytes in *length.
//
// some of the values for the IDs are below; for more see the truetype spec:
//     http://developer.apple.com/textfonts/TTRefMan/RM06/Chap6name.html
//     http://www.microsoft.com/typography/otspec/name.htm
//
// returns results in whatever encoding you request... but note that 2-byte encodings
// will be BIG-ENDIAN... use stbtt_CompareUTF8toUTF16_bigendian() to compare
const char *stbtt_GetFontNameString(const stbtt_fontinfo *font, int *length,
                                    int platformID, int encodingID,
                                    int languageID, int nameID)
{
   int32_t i,count,stringOffset;
   uint8_t *fc = font->data;
   uint32_t offset = font->fontstart;
   uint32_t nm = stbtt__find_table(fc, offset, "name");
   if (!nm) return NULL;
   count = ttUSHORT(fc+nm+2);
   stringOffset = nm + ttUSHORT(fc+nm+4);
   for (i=0; i < count; ++i) {
      uint32_t loc = nm + 6 + 12 * i;
      if (platformID == ttUSHORT(fc+loc+0) && encodingID == ttUSHORT(fc+loc+2)
          && languageID == ttUSHORT(fc+loc+4) && nameID == ttUSHORT(fc+loc+6)) {
         *length = ttUSHORT(fc+loc+8);
         return (const char *) (fc+stringOffset+ttUSHORT(fc+loc+10));
      }
   }
   return NULL;
}

static int stbtt__matchpair(uint8_t *fc, uint32_t nm, uint8_t *name, int32_t nlen, int32_t target_id, int32_t next_id)
{
   int32_t i;
   int32_t count = ttUSHORT(fc+nm+2);
   int32_t stringOffset = nm + ttUSHORT(fc+nm+4);
   for (i=0; i < count; ++i) {
      uint32_t loc = nm + 6 + 12 * i;
      int32_t id = ttUSHORT(fc+loc+6);
      if (id == target_id) {
         // find the encoding
         int32_t platform = ttUSHORT(fc+loc+0), encoding = ttUSHORT(fc+loc+2), language = ttUSHORT(fc+loc+4);
         // is this a Unicode encoding?
         if (platform == 0 || (platform == 3 && encoding == 1) || (platform == 3 && encoding == 10)) {
            int32_t slen = ttUSHORT(fc+loc+8);
            int32_t off = ttUSHORT(fc+loc+10);
            // check if there's a prefix match
            int32_t matchlen = stbtt__CompareUTF8toUTF16_bigendian_prefix(name, nlen, fc+stringOffset+off,slen);
            if (matchlen >= 0) {
               // check for target_id+1 immediately following, with same encoding & language
               if (i+1 < count && ttUSHORT(fc+loc+12+6) == next_id && ttUSHORT(fc+loc+12) == platform && ttUSHORT(fc+loc+12+2) == encoding && ttUSHORT(fc+loc+12+4) == language) {
                  slen = ttUSHORT(fc+loc+12+8);
                  off = ttUSHORT(fc+loc+12+10);
                  if (slen == 0) {
                     if (matchlen == nlen)
                        return 1;
                  } else if (matchlen < nlen && name[matchlen] == ' ') {
                     ++matchlen;
                     if (stbtt_CompareUTF8toUTF16_bigendian_internal((char*) (name+matchlen), nlen-matchlen, (char*)(fc+stringOffset+off),slen))
                        return 1;
                  }
               } else {
                  // if nothing immediately following
                  if (matchlen == nlen)
                     return 1;
               }
            }
         }
         // @TODO handle other encodings
      }
   }
   return 0;
}

static int stbtt__matches(uint8_t *fc, uint32_t offset, uint8_t *name, int32_t flags)
{
   int32_t nlen = (int32_t) strlen((char *) name);
   uint32_t nm,hd;
   if (!stbtt__isfont(fc+offset)) return 0;
   // check italics/bold/underline flags in macStyle...
   if (flags) {
      hd = stbtt__find_table(fc, offset, "head");
      if ((ttUSHORT(fc+hd+44) & 7) != (flags & 7)) return 0;
   }
   nm = stbtt__find_table(fc, offset, "name");
   if (!nm) return 0;
   if (flags) {
      // if we checked the macStyle flags, then just check the family and ignore the subfamily
      if (stbtt__matchpair(fc, nm, name, nlen, 16, -1))  return 1;
      if (stbtt__matchpair(fc, nm, name, nlen,  1, -1))  return 1;
      if (stbtt__matchpair(fc, nm, name, nlen,  3, -1))  return 1;
   } else {
      if (stbtt__matchpair(fc, nm, name, nlen, 16, 17))  return 1;
      if (stbtt__matchpair(fc, nm, name, nlen,  1,  2))  return 1;
      if (stbtt__matchpair(fc, nm, name, nlen,  3, -1))  return 1;
   }
   return 0;
}

static int stbtt_FindMatchingFont_internal(unsigned char *font_collection,
                                           char *name_utf8, int32_t flags)
{
   int32_t i;
   for (i=0;;++i) {
      int32_t off = stbtt_GetFontOffsetForIndex(font_collection, i);
      if (off < 0) return off;
      if (stbtt__matches((uint8_t *) font_collection, off, (uint8_t*) name_utf8, flags))
         return off;
   }
}

#if defined(__GNUC__) || defined(__clang__)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wcast-qual"
#endif

int stbtt_BakeFontBitmap(const unsigned char *data, int offset,
                         float pixel_height, unsigned char *pixels, int pw, int ph,
                         int first_char, int num_chars, stbtt_bakedchar *chardata)
{
   return stbtt_BakeFontBitmap_internal((unsigned char *) data, offset, pixel_height, pixels, pw, ph, first_char, num_chars, chardata);
}

// Each .ttf/.ttc file may have more than one font. Each font has a sequential
// index number starting from 0. Call this function to get the font offset for
// a given index; it returns -1 if the index is out of range. A regular .ttf
// file will only define one font and it always be at offset 0, so it will
// return '0' for index 0, and -1 for all other indices.
int stbtt_GetFontOffsetForIndex(const unsigned char *data, int index)
{
   return stbtt_GetFontOffsetForIndex_internal((unsigned char *) data, index);
}

// This function will determine the number of fonts in a font file.  TrueType
// collection (.ttc) files may contain multiple fonts, while TrueType font
// (.ttf) files only contain one font. The number of fonts can be used for
// indexing with the previous function where the index is between zero and one
// less than the total fonts. If an error occurs, -1 is returned.
int stbtt_GetNumberOfFonts(const unsigned char *data)
{
   return stbtt_GetNumberOfFonts_internal((unsigned char *) data);
}

// Given an offset into the file that defines a font, this function builds
// the necessary cached info for the rest of the system. You must allocate
// the stbtt_fontinfo yourself, and stbtt_InitFont will fill it out. You don't
// need to do anything special to free it, because the contents are pure
// value data with no additional data structures. Returns 0 on failure.
int stbtt_InitFont(stbtt_fontinfo *info, const unsigned char *data, int offset)
{
   return stbtt_InitFont_internal(info, (unsigned char *) data, offset);
}

// Finding the right font...
//
// You should really just solve this offline, keep your own tables
// of what font is what, and don't try to get it out of the .ttf file.
// That's because getting it out of the .ttf file is really hard, because
// the names in the file can appear in many possible encodings, in many
// possible languages, and e.g. if you need a case-insensitive comparison,
// the details of that depend on the encoding & language in a complex way
// (actually underspecified in truetype, but also gigantic).
//
// But you can use the provided functions in two possible ways:
//     stbtt_FindMatchingFont() will use *case-sensitive* comparisons on
//             unicode-encoded names to try to find the font you want;
//             you can run this before calling stbtt_InitFont()
//
//     stbtt_GetFontNameString() lets you get any of the various strings
//             from the file yourself and do your own comparisons on them.
//             You have to have called stbtt_InitFont() first.

// returns the offset (not index) of the font that matches, or -1 if none
//   if you use STBTT_MACSTYLE_DONTCARE, use a font name like "Arial Bold".
//   if you use any other flag, use a font name like "Arial"; this checks
//     the 'macStyle' header field; i don't know if fonts set this consistently
int stbtt_FindMatchingFont(const unsigned char *fontdata, const char *name, int flags)
{
   return stbtt_FindMatchingFont_internal((unsigned char *) fontdata, (char *) name, flags);
}

// returns 1/0 whether the first string interpreted as utf8 is identical to
// the second string interpreted as big-endian utf16... useful for strings from next func
int stbtt_CompareUTF8toUTF16_bigendian(const char *s1, int len1, const char *s2, int len2)
{
   return stbtt_CompareUTF8toUTF16_bigendian_internal((char *) s1, len1, (char *) s2, len2);
}

// FULL VERSION HISTORY
//
//   1.25 (2021-07-11) many fixes
//   1.24 (2020-02-05) fix warning
//   1.23 (2020-02-02) query SVG data for glyphs; query whole kerning table (but only kern not GPOS)
//   1.22 (2019-08-11) minimize missing-glyph duplication; fix kerning if both 'GPOS' and 'kern' are defined
//   1.21 (2019-02-25) fix warning
//   1.20 (2019-02-07) PackFontRange skips missing codepoints; GetScaleFontVMetrics()
//   1.19 (2018-02-11) OpenType GPOS kerning (horizontal only), fmod
//   1.18 (2018-01-29) add missing function
//   1.17 (2017-07-23) make more arguments const; doc fix
//   1.16 (2017-07-12) SDF support
//   1.15 (2017-03-03) make more arguments const
//   1.14 (2017-01-16) num-fonts-in-TTC function
//   1.13 (2017-01-02) support OpenType fonts, certain Apple fonts
//   1.12 (2016-10-25) suppress warnings about casting away const with -Wcast-qual
//   1.11 (2016-04-02) fix unused-variable warning
//   1.10 (2016-04-02) allow user-defined fabs() replacement
//                     fix memory leak if fontsize=0.0
//                     fix warning from duplicate typedef
//   1.09 (2016-01-16) warning fix; avoid crash on outofmem; use alloc userdata for PackFontRanges
//   1.08 (2015-09-13) document stbtt_Rasterize(); fixes for vertical & horizontal edges
//   1.07 (2015-08-01) allow PackFontRanges to accept arrays of sparse codepoints;
//                     allow PackFontRanges to pack and render in separate phases;
//                     fix stbtt_GetFontOFfsetForIndex (never worked for non-0 input?);
//                     fixed an ASSERT() bug in the new rasterizer
//                     replace ASSERT() with ASSERT() in new rasterizer
//   1.06 (2015-07-14) performance improvements (~35% faster on x86 and x64 on test machine)
//                     also more precise AA rasterizer, except if shapes overlap
//                     remove need for STBTT_sort
//   1.05 (2015-04-15) fix misplaced definitions for STBTT_STATIC
//   1.04 (2015-04-15) typo in example
//   1.03 (2015-04-12) STBTT_STATIC, fix memory leak in new packing, various fixes
//   1.02 (2014-12-10) fix various warnings & compile issues w/ stb_rect_pack, C++
//   1.01 (2014-12-08) fix subpixel position when oversampling to exactly match
//                        non-oversampled; STBTT_POINT_SIZE for packed case only
//   1.00 (2014-12-06) add new PackBegin etc. API, w/ support for oversampling
//   0.99 (2014-09-18) fix multiple bugs with subpixel rendering (ryg)
//   0.9  (2014-08-07) support certain mac/iOS fonts without an MS platformID
//   0.8b (2014-07-07) fix a warning
//   0.8  (2014-05-25) fix a few more warnings
//   0.7  (2013-09-25) bugfix: subpixel glyph bug fixed in 0.5 had come back
//   0.6c (2012-07-24) improve documentation
//   0.6b (2012-07-20) fix a few more warnings
//   0.6  (2012-07-17) fix warnings; added stbtt_ScaleForMappingEmToPixels,
//                        stbtt_GetFontBoundingBox, stbtt_IsGlyphEmpty
//   0.5  (2011-12-09) bugfixes:
//                        subpixel glyph renderer computed wrong bounding box
//                        first vertex of shape can be off-curve (FreeSans)
//   0.4b (2011-12-03) fixed an error in the font baking example
//   0.4  (2011-12-01) kerning, subpixel rendering (tor)
//                    bugfixes for:
//                        codepoint-to-glyph conversion using table fmt=12
//                        codepoint-to-glyph conversion using table fmt=4
//                        stbtt_GetBakedQuad with non-square texture (Zer)
//                    updated Hello World! sample to use kerning and subpixel
//                    fixed some warnings
//   0.3  (2009-06-24) cmap fmt=12, compound shapes (MM)
//                    userdata, malloc-from-userdata, non-zero fill (stb)
//   0.2  (2009-03-11) Fix unsigned/signed char warnings
//   0.1  (2009-03-09) First public release
//
