text: /*
   * Copyright © 2012  Google, Inc.
   *
   *  This is part of HarfBuzz, a text shaping library.
   *
   * Permission is hereby granted, without written agreement and without
   * license or royalty fees, to use, copy, modify, and distribute this
   * software and its documentation for any purpose, provided that the
   * above copyright notice and the following two paragraphs appear in
   * all copies of this software.
   *
   * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
   * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
   * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
   * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
   * DAMAGE.
   *
   * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
   * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
   * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
   * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
   * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
   *
   * Google Author(s): Behdad Esfahbod
   */
  
  #ifndef ANSI_PRINT_HH
  #define ANSI_PRINT_HH
  
  #include "hb.hh"
  
  #include <assert.h>
  #include <stdlib.h>
  #include <stddef.h>
  #include <string.h>
  #include <stdio.h>
  #include <math.h>
  #include <fcntl.h>
  #ifdef HAVE_UNISTD_H
  #include <unistd.h> /* for isatty() */
  #endif
  
  #if defined (_MSC_VER) && (_MSC_VER < 1800)
  static inline long int
  lround (double x)
  {
    if (x >= 0)
      return floor (x + 0.5);
    else
      return ceil (x - 0.5);
  }
  #endif
  
  #define ESC_E (char)27
  
  #define CELL_W 8
  #define CELL_H (2 * CELL_W)
  
  struct color_diff_t
  {
    int dot (const color_diff_t &o)
    { return v[0]*o.v[0] + v[1]*o.v[1] + v[2]*o.v[2] + v[3]*o.v[3]; }
  
    int v[4];
  };
  
  struct color_t
  {
    static color_t from_ansi (unsigned int x)
    {
      color_t c = {(0xFFu<<24) | ((0xFFu*(x&1))<<16) | ((0xFFu*((x >> 1)&1))<<8) | (0xFFu*((x >> 2)&1))};
      return c;
    }
    unsigned int to_ansi ()
    {
      return ((v >> 23) & 1) | ((v >> 14)&2) | ((v >> 5)&4);
    }
  
    color_diff_t diff (const color_t &o)
    {
      color_diff_t d;
      for (unsigned int i = 0; i < 4; i++)
        d.v[i] = (int) ((v >> (i*8))&0xFF) - (int) ((o.v >> (i*8))&0xFF);
      return d;
    }
  
    uint32_t v;
  };
  
  struct image_t
  {
    public:
  
    image_t (unsigned int width_,
  	   unsigned int height_,
  	   const uint32_t *data_,
  	   unsigned int stride_) :
  		width (width_),
  		height (height_),
  		own_data (false),
  		data ((color_t *) data_),
  		stride (stride_) {}
    image_t (unsigned int width_,
  	   unsigned int height_) :
  		width (width_),
  		height (height_),
  		own_data (true),
  		data ((color_t *) malloc (sizeof (data[0]) * width * height)),
  		stride (width) {}
    ~image_t ()
    { if (own_data) free (data); }
  
    color_t &operator () (unsigned int x, unsigned int y)
    { return data[x + y * stride]; }
  
    color_t operator () (unsigned int x, unsigned int y) const
    { return data[x + y * stride]; }
  
    void
    copy_sub_image (const image_t &s,
  		  unsigned int x, unsigned int y,
  		  unsigned int w, unsigned int h)
    {
      assert (x < width);
      assert (y < height);
      for (unsigned int row = 0; row < h; row++) {
        color_t *p = data + x + hb_min (y + row, height - 1) * stride;
        color_t *q = s.data + row * s.stride;
        if (x + w <= width)
  	for (unsigned int col = 0; col < w; col++)
  	  *q++ = *p++;
        else {
  	unsigned int limit = width - x;
  	for (unsigned int col = 0; col < limit; col++)
  	  *q++ = *p++;
  	p--;
  	for (unsigned int col = limit; col < w; col++)
  	  *q++ = *p;
        }
      }
    }
  
    const unsigned int width;
    const unsigned int height;
  
    private:
    bool own_data;
    color_t * const data;
    const unsigned int stride;
  };
  
  struct biimage_t
  {
    public:
  
    biimage_t (unsigned int width, unsigned int height) :
  		width (width),
  		height (height),
  		bg (0), fg (0), unicolor (true),
  		data ((uint8_t *) malloc (sizeof (data[0]) * width * height)) {}
    ~biimage_t ()
    { free (data); }
  
    void set (const image_t &image)
    {
      assert (image.width == width);
      assert (image.height == height);
      int freq[8] = {0};
      for (unsigned int y = 0; y < height; y++)
        for (unsigned int x = 0; x < width; x++) {
  	color_t c = image (x, y);
  	freq[c.to_ansi ()]++;
        }
      bg = 0;
      for (unsigned int i = 1; i < 8; i++)
        if (freq[bg] < freq[i])
  	bg = i;
      fg = 0;
      for (unsigned int i = 1; i < 8; i++)
        if (i != bg && freq[fg] < freq[i])
  	fg = i;
      if (fg == bg || freq[fg] == 0) {
        fg = bg;
        unicolor = true;
      }
      else
        unicolor = false;
  
      /* Set the data... */
  
      if (unicolor) {
        memset (data, 0, sizeof (data[0]) * width * height);
        return;
      }
  
      color_t bgc = color_t::from_ansi (bg);
      color_t fgc = color_t::from_ansi (fg);
      color_diff_t diff = fgc.diff (bgc);
      int dd = diff.dot (diff);
      for (unsigned int y = 0; y < height; y++)
        for (unsigned int x = 0; x < width; x++) {
  	int d = diff.dot (image (x, y).diff (bgc));
  	(*this)(x, y) = d < 0 ? 0 : d > dd ? 255 : lround (d * 255. / dd);
        }
    }
  
    uint8_t &operator () (unsigned int x, unsigned int y)
    { return data[x + y * width]; }
  
    uint8_t operator () (unsigned int x, unsigned int y) const
    { return data[x + y * width]; }
  
    const unsigned int width;
    const unsigned int height;
    unsigned int bg;
    unsigned int fg;
    bool unicolor;
  
    private:
    uint8_t * const data;
  };
  
  static const char *
  block_best (const biimage_t &bi, bool *inverse)
  {
    assert (bi.width  <= CELL_W);
    assert (bi.height <= CELL_H);
  
    unsigned int score = UINT_MAX;
    unsigned int row_sum[CELL_H] = {0};
    unsigned int col_sum[CELL_W] = {0};
    unsigned int row_sum_i[CELL_H] = {0};
    unsigned int col_sum_i[CELL_W] = {0};
    unsigned int quad[2][2] = {{0}};
    unsigned int quad_i[2][2] = {{0}};
    unsigned int total = 0;
    unsigned int total_i = 0;
    for (unsigned int y = 0; y < bi.height; y++)
      for (unsigned int x = 0; x < bi.width; x++) {
        unsigned int c = bi (x, y);
        unsigned int c_i = 255 - c;
        row_sum[y] += c;
        row_sum_i[y] += c_i;
        col_sum[x] += c;
        col_sum_i[x] += c_i;
        quad[2 * y / bi.height][2 * x / bi.width] += c;
        quad_i[2 * y / bi.height][2 * x / bi.width] += c_i;
        total += c;
        total_i += c_i;
      }
  
    /* Make the sums cummulative */
    for (unsigned int i = 1; i < bi.height; i++) {
      row_sum[i] += row_sum[i - 1];
      row_sum_i[i] += row_sum_i[i - 1];
    }
    for (unsigned int i = 1; i < bi.width;  i++) {
      col_sum[i] += col_sum[i - 1];
      col_sum_i[i] += col_sum_i[i - 1];
    }
  
    const char *best_c = " ";
  
    /* Maybe empty is better! */
    if (total < score) {
      score = total;
      *inverse = false;
      best_c = " ";
    }
    /* Maybe full is better! */
    if (total_i < score) {
      score = total_i;
      *inverse = true;
      best_c = " ";
    }
  
    /* Find best lower line */
    if (1) {
      unsigned int best_s = UINT_MAX;
      bool best_inv = false;
      int best_i = 0;
      for (unsigned int i = 0; i < bi.height - 1; i++)
      {
        unsigned int s;
        s = row_sum[i] + total_i - row_sum_i[i];
        if (s < best_s) {
  	best_s = s;
  	best_i = i;
  	best_inv = false;
        }
        s = row_sum_i[i] + total - row_sum[i];
        if (s < best_s) {
  	best_s = s;
  	best_i = i;
  	best_inv = true;
        }
      }
      if (best_s < score) {
        static const char *lower[7] = {"▁", "▂", "▃", "▄", "▅", "▆", "▇"};
        unsigned int which = lround ((double) ((best_i + 1) * 8) / bi.height);
        if (1 <= which && which <= 7) {
  	score = best_s;
  	*inverse = best_inv;
  	best_c = lower[7 - which];
        }
      }
    }
  
    /* Find best left line */
    if (1) {
      unsigned int best_s = UINT_MAX;
      bool best_inv = false;
      int best_i = 0;
      for (unsigned int i = 0; i < bi.width - 1; i++)
      {
        unsigned int s;
        s = col_sum[i] + total_i - col_sum_i[i];
        if (s < best_s) {
  	best_s = s;
  	best_i = i;
  	best_inv = true;
        }
        s = col_sum_i[i] + total - col_sum[i];
        if (s < best_s) {
  	best_s = s;
  	best_i = i;
  	best_inv = false;
        }
      }
      if (best_s < score) {
        static const char *left [7] = {"▏", "▎", "▍", "▌", "▋", "▊", "▉"};
        unsigned int which = lround ((double) ((best_i + 1) * 8) / bi.width);
        if (1 <= which && which <= 7) {
  	score = best_s;
  	*inverse = best_inv;
  	best_c = left[which - 1];
        }
      }
    }
  
    /* Find best quadrant */
    if (1) {
      unsigned int q = 0;
      unsigned int qs = 0;
      for (unsigned int i = 0; i < 2; i++)
        for (unsigned int j = 0; j < 2; j++)
  	if (quad[i][j] > quad_i[i][j]) {
  	  q += 1 << (2 * i + j);
  	  qs += quad_i[i][j];
  	} else
  	  qs += quad[i][j];
      if (qs < score) {
        const char *c = nullptr;
        bool inv = false;
        switch (q) {
  	case 1:  c = "▟"; inv = true;  break;
  	case 2:  c = "▙"; inv = true;  break;
  	case 4:  c = "▖"; inv = false; break;
  	case 8:  c = "▗"; inv = false; break;
  	case 9:  c = "▚"; inv = false; break;
  	case 6:  c = "▞"; inv = false; break;
  	case 7:  c = "▜"; inv = true;  break;
  	case 11: c = "▜"; inv = true;  break;
  	case 13: c = "▙"; inv = true;  break;
  	case 14: c = "▟"; inv = true;  break;
        }
        if (c) {
  	score = qs;
  	*inverse = inv;
  	best_c = c;
        }
      }
    }
  
    return best_c;
  }
  
  static inline void
  ansi_print_image_rgb24 (const uint32_t *data,
  			unsigned int width,
  			unsigned int height,
  			unsigned int stride)
  {
    image_t image (width, height, data, stride);
  
    unsigned int rows = (height + CELL_H - 1) / CELL_H;
    unsigned int cols = (width +  CELL_W - 1) / CELL_W;
    image_t cell (CELL_W, CELL_H);
    biimage_t bi (CELL_W, CELL_H);
    unsigned int last_bg = -1, last_fg = -1;
    for (unsigned int row = 0; row < rows; row++) {
      for (unsigned int col = 0; col < cols; col++) {
        image.copy_sub_image (cell, col * CELL_W, row * CELL_H, CELL_W, CELL_H);
        bi.set (cell);
        if (bi.unicolor) {
  	if (last_bg != bi.bg) {
  	  printf ("%c[%dm", ESC_E, 40 + bi.bg);
  	  last_bg = bi.bg;
  	}
  	printf (" ");
        } else {
  	/* Figure out the closest character to the biimage */
  	bool inverse = false;
  	const char *c = block_best (bi, &inverse);
  	if (inverse) {
  	  if (last_bg != bi.fg || last_fg != bi.bg) {
  	    printf ("%c[%d;%dm", ESC_E, 30 + bi.bg, 40 + bi.fg);
  	    last_bg = bi.fg;
  	    last_fg = bi.bg;
  	  }
  	} else {
  	  if (last_bg != bi.bg || last_fg != bi.fg) {
  	    printf ("%c[%d;%dm", ESC_E, 40 + bi.bg, 30 + bi.fg);
  	    last_bg = bi.bg;
  	    last_fg = bi.fg;
  	  }
  	}
  	printf ("%s", c);
        }
      }
      printf ("%c[0m\n", ESC_E); /* Reset */
      last_bg = last_fg = -1;
    }
  }
  
  #endif
  