text: /*
  libdrawtext - a simple library for fast text rendering in OpenGL
  Copyright (C) 2011-2014  John Tsiombikas <nuclear@member.fsf.org>
  
  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.
  
  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU Lesser General Public License for more details.
  
  You should have received a copy of the GNU Lesser General Public License
  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
  #ifndef LIBDRAWTEXT_H_
  #define LIBDRAWTEXT_H_
  
  #include <stdio.h>
  #include <stdlib.h>
  
  struct dtx_font;
  struct dtx_glyphmap;
  
  /* draw buffering modes */
  enum {
  	DTX_NBF,	/* unbuffered */
  	DTX_LBF,	/* line buffered */
  	DTX_FBF		/* fully buffered */
  };
  
  struct dtx_box {
  	float x, y;
  	float width, height;
  };
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  /* Open a truetype/opentype/whatever font.
   *
   * If sz is non-zero, the default ASCII glyphmap at the requested point size is
   * automatically created as well, and ready to use.
   *
   * To use other unicode ranges and different font sizes you must first call
   * dtx_prepare or dtx_prepare_range before issuing any drawing calls, otherwise
   * nothing will be rendered.
   */
  struct dtx_font *dtx_open_font(const char *fname, int sz);
  /* open a font by loading a precompiled glyphmap (see: dtx_save_glyphmap)
   * this works even when compiled without freetype support
   */
  struct dtx_font *dtx_open_font_glyphmap(const char *fname);
  /* close a font opened by either of the above */
  void dtx_close_font(struct dtx_font *fnt);
  
  /* prepare an ASCII glyphmap for the specified font size */
  void dtx_prepare(struct dtx_font *fnt, int sz);
  /* prepare an arbitrary unicode range glyphmap for the specified font size */
  void dtx_prepare_range(struct dtx_font *fnt, int sz, int cstart, int cend);
  
  /* Finds the glyphmap that contains the specified character code and matches the requested size
   * Returns null if it hasn't been created (you should call dtx_prepare/dtx_prepare_range).
   */
  struct dtx_glyphmap *dtx_get_font_glyphmap(struct dtx_font *fnt, int sz, int code);
  
  /* Finds the glyphmap that contains the specified unicode range and matches the requested font size
   * Will automatically generate one if it can't find it.
   */
  struct dtx_glyphmap *dtx_get_font_glyphmap_range(struct dtx_font *fnt, int sz, int cstart, int cend);
  
  /* Creates and returns a glyphmap for a particular unicode range and font size.
   * The generated glyphmap is added to the font's list of glyphmaps.
   */
  struct dtx_glyphmap *dtx_create_glyphmap_range(struct dtx_font *fnt, int sz, int cstart, int cend);
  /* free a glyphmap */
  void dtx_free_glyphmap(struct dtx_glyphmap *gmap);
  
  /* returns a pointer to the raster image of a glyphmap (1 byte per pixel grayscale) */
  unsigned char *dtx_get_glyphmap_image(struct dtx_glyphmap *gmap);
  /* returns the width of the glyphmap image in pixels */
  int dtx_get_glyphmap_width(struct dtx_glyphmap *gmap);
  /* returns the height of the glyphmap image in pixels */
  int dtx_get_glyphmap_height(struct dtx_glyphmap *gmap);
  
  /* The following functions can be used even when the library is compiled without
   * freetype support.
   */
  struct dtx_glyphmap *dtx_load_glyphmap(const char *fname);
  struct dtx_glyphmap *dtx_load_glyphmap_stream(FILE *fp);
  int dtx_save_glyphmap(const char *fname, const struct dtx_glyphmap *gmap);
  int dtx_save_glyphmap_stream(FILE *fp, const struct dtx_glyphmap *gmap);
  
  /* adds a glyphmap to a font */
  void dtx_add_glyphmap(struct dtx_font *fnt, struct dtx_glyphmap *gmap);
  
  /* ---- rendering ---- */
  
  /* before drawing anything this function must set the font to use */
  void dtx_use_font(struct dtx_font *fnt, int sz);
  
  /* sets the buffering mode
   * - DTX_NBUF: every call to dtx_string gets rendered immediately.
   * - DTX_LBUF: renders when the buffer is full or the string contains a newline.
   * - DTX_FBUF: renders only when the buffer is full (you must call dtx_flush explicitly).
   */
  void dtx_draw_buffering(int mode);
  
  /* Sets the vertex attribute indices to use for passing vertex and texture coordinate
   * data. By default both are -1 which means you don't have to use a shader, and if you
   * do they are accessible through gl_Vertex and gl_MultiTexCoord0, as usual.
   *
   * NOTE: If you are using OpenGL ES 2.x or OpenGL >= 3.1 pure (non-compatibility) context
   * you must specify valid attribute indices.
   */
  void dtx_vertex_attribs(int vert_attr, int tex_attr);
  
  /* draws a single glyph at the origin */
  void dtx_glyph(int code);
  /* draws a utf-8 string starting at the origin. \n \r and \t are handled appropriately. */
  void dtx_string(const char *strz, struct dtx_box *box);
  
  void dtx_printf(const char *fmt, ...);
  
  /* render any pending glyphs (see dtx_draw_buffering) */
  void dtx_flush(void);
  
  
  /* ---- encodings ---- */
  
  /* returns a pointer to the next character in a utf-8 stream */
  char *dtx_utf8_next_char(char *str);
  
  /* returns the unicode character codepoint of the utf-8 character starting at str */
  int dtx_utf8_char_code(const char *str);
  
  /* returns the number of bytes of the utf-8 character starting at str */
  int dtx_utf8_nbytes(const char *str);
  
  /* returns the number of utf-8 character in a zero-terminated utf-8 string */
  int dtx_utf8_char_count(const char *str);
  
  /* Converts a unicode code-point to a utf-8 character by filling in the buffer
   * passed at the second argument, and returns the number of bytes taken by that
   * utf-8 character.
   * It's valid to pass a null buffer pointer, in which case only the byte count is
   * returned (useful to figure out how much memory to allocate for a buffer).
   */
  size_t dtx_utf8_from_char_code(int code, char *buf);
  
  /* Converts a unicode utf-16 wchar_t string to utf-8, filling in the buffer passed
   * at the second argument. Returns the size of the resulting string in bytes.
   *
   * It's valid to pass a null buffer pointer, in which case only the size gets
   * calculated and returned, which is useful for figuring out how much memory to
   * allocate for the utf-8 buffer.
   */
  size_t dtx_utf8_from_string(const wchar_t *str, char *buf);
  
  
  /* ---- metrics ---- */
  float dtx_line_height(void);
  
  /* rendered dimensions of a single glyph */
  void dtx_glyph_box(int code, struct dtx_box *box);
  float dtx_glyph_width(int code);
  float dtx_glyph_height(int code);
  
  /* rendered dimensions of a string */
  void dtx_string_box(const char *str, struct dtx_box *box);
  float dtx_string_width(const char *str);
  float dtx_string_height(const char *str);
  
  /* returns the horizontal position of the n-th character of the rendered string
   * (useful for placing cursors)
   */
  float dtx_char_pos(const char *str, int n);
  
  int dtx_char_at_pt(const char *str, float pt);
  
  #ifdef __cplusplus
  }
  #endif
  
  #endif	/* LIBDRAWTEXT_H_ */
  