font.c

/*         ______   ___    ___
 *        /\  _  \ /\_ \  /\_ \
 *        \ \ \L\ \\//\ \ \//\ \      __     __   _ __   ___
 *         \ \  __ \ \ \ \  \ \ \   /'__`\ /'_ `\/\`'__\/ __`\
 *          \ \ \/\ \ \_\ \_ \_\ \_/\  __//\ \L\ \ \ \//\ \L\ \
 *           \ \_\ \_\/\____\/\____\ \____\ \____ \ \_\\ \____/
 *            \/_/\/_/\/____/\/____/\/____/\/___L\ \/_/ \/___/
 *                                           /\____/
 *                                           \_/__/
 *
 *
 *      See readme.txt for copyright information.
 */

#include <string.h>
#include "allegro5/allegro.h"
#include "allegro5/allegro_font.h"
#include "allegro5/internal/aintern.h"
#include "allegro5/internal/aintern_bitmap.h"
#include "allegro5/internal/aintern_font.h"
#include "allegro5/internal/aintern_exitfunc.h"
#include "allegro5/internal/aintern_vector.h"

#include "font.h"
#include <ctype.h>

ALLEGRO_DEBUG_CHANNEL("font")


typedef struct
{
   ALLEGRO_USTR *extension;
   ALLEGRO_FONT *(*load_font)(char const *filename, int size, int flags);
} FONT_HANDLER;


/* globals */
static bool font_inited = false;
static _AL_VECTOR font_handlers;


/* al_font_404_character:
 *  This is what we render missing glyphs as.
 */
static int al_font_404_character = '^';



/* font_height:
 *  (mono and color vtable entry)
 *  Returns the height, in pixels of the font.
 */
static int font_height(const ALLEGRO_FONT *f)
{
   ASSERT(f);
   return f->height;
}



static int font_ascent(const ALLEGRO_FONT *f)
{
    return font_height(f);
}



static int font_descent(const ALLEGRO_FONT *f)
{
    (void)f;
    return 0;
}



/* length:
 *  (mono and color vtable entry)
 *  Returns the length, in pixels, of a string as rendered in a font.
 */
static int length(const ALLEGRO_FONT* f, const ALLEGRO_USTR *text)
{
    int ch = 0, w = 0;
    int pos = 0;
    ASSERT(f);

    while ((ch = al_ustr_get_next(text, &pos)) >= 0) {
        w += f->vtable->char_length(f, ch);
    }

    return w;
}



static void color_get_text_dimensions(ALLEGRO_FONT const *f,
   const ALLEGRO_USTR *text,
   int *bbx, int *bby, int *bbw, int *bbh)
{
   /* Dummy implementation - for A4-style bitmap fonts the bounding
    * box of text is its width and line-height.
    */
   int h = al_get_font_line_height(f);
   if (bbx) *bbx = 0;
   if (bby) *bby = 0;
   if (bbw) *bbw = length(f, text);
   if (bbh) *bbh = h;
}



static ALLEGRO_FONT_COLOR_DATA *_al_font_find_page(
   ALLEGRO_FONT_COLOR_DATA *cf, int ch)
{
    while (cf) {
        if (ch >= cf->begin && ch < cf->end)
            return cf;
        cf = cf->next;
    }
    return NULL;
}


/* _color_find_glyph:
 *  Helper for color vtable entries, below.
 */
static ALLEGRO_BITMAP* _al_font_color_find_glyph(const ALLEGRO_FONT* f, int ch)
{
    ALLEGRO_FONT_COLOR_DATA* cf = (ALLEGRO_FONT_COLOR_DATA*)(f->data);

    cf = _al_font_find_page(cf, ch);
    if (cf) {
        return cf->bitmaps[ch - cf->begin];
    }

    /* if we don't find the character, then search for the missing
       glyph, but don't get stuck in a loop. */
    if (ch != al_font_404_character && !f->fallback)
        return _al_font_color_find_glyph(f, al_font_404_character);
    return 0;
}



/* color_char_length:
 *  (color vtable entry)
 *  Returns the length of a character, in pixels, as it would be rendered
 *  in this font.
 */
static int color_char_length(const ALLEGRO_FONT* f, int ch)
{
   ALLEGRO_BITMAP* g = _al_font_color_find_glyph(f, ch);
   if (g)
      return al_get_bitmap_width(g);
   if (f->fallback)
      return al_get_glyph_width(f->fallback, ch);
   return 0;
}



/* color_render_char:
 *  (color vtable entry)
 *  Renders a color character onto a bitmap, at the specified location,
 *  using the specified color.
 *  Returns the character width, in pixels.
 */
static int color_render_char(const ALLEGRO_FONT* f,
   ALLEGRO_COLOR color, int ch, float x,
   float y)
{
   int w = 0;
   int h = f->vtable->font_height(f);
   ALLEGRO_BITMAP *g;

   g = _al_font_color_find_glyph(f, ch);
   if (g) {
      al_draw_tinted_bitmap(g, color, x,
         y + ((float)h - al_get_bitmap_height(g))/2.0f, 0);

      w = al_get_bitmap_width(g);
   }
   else if (f->fallback) {
      al_draw_glyph(f->fallback, color, x, y, ch);
      w = al_get_glyph_width(f->fallback, ch);
   }

   return w;
}

/* color_render:
 *  (color vtable entry)
 *  Renders a color font onto a bitmap, at the specified location, using
 *  the specified color.
 */
static int color_render(const ALLEGRO_FONT* f, ALLEGRO_COLOR color,
   const ALLEGRO_USTR *text,
    float x, float y)
{
    int pos = 0;
    int advance = 0;
    int32_t ch;
    bool held = al_is_bitmap_drawing_held();

    al_hold_bitmap_drawing(true);
    while ((ch = al_ustr_get_next(text, &pos)) >= 0) {
        advance += f->vtable->render_char(f, color, ch, x + advance, y);
    }
    al_hold_bitmap_drawing(held);
    return advance;
}


static bool color_get_glyph(const ALLEGRO_FONT *f, int prev_codepoint, int codepoint, ALLEGRO_GLYPH *glyph)
{
   ALLEGRO_BITMAP *g = _al_font_color_find_glyph(f, codepoint);
   if (g) {
      glyph->bitmap = g;
      glyph->x = 0;
      glyph->y = 0;
      glyph->w = al_get_bitmap_width(g);
      glyph->h = al_get_bitmap_height(g);
      glyph->kerning = 0;
      glyph->offset_x = 0;
      glyph->offset_y = 0;
      glyph->advance = glyph->w;
      return true;
   }
   if (f->fallback) {
      return f->fallback->vtable->get_glyph(f->fallback, prev_codepoint, codepoint, glyph);
   }
   return false;
}


/* color_destroy:
 *  (color vtable entry)
 *  Destroys a color font.
 */
static void color_destroy(ALLEGRO_FONT* f)
{
    ALLEGRO_FONT_COLOR_DATA* cf;
    ALLEGRO_BITMAP *glyphs = NULL;

    if (!f)
        return;

    cf = (ALLEGRO_FONT_COLOR_DATA*)(f->data);

    if (cf)
        glyphs = cf->glyphs;

    while (cf) {
        ALLEGRO_FONT_COLOR_DATA* next = cf->next;
        int i = 0;

        for (i = cf->begin; i < cf->end; i++) al_destroy_bitmap(cf->bitmaps[i - cf->begin]);
        /* Each range might point to the same bitmap. */
        if (cf->glyphs != glyphs) {
            al_destroy_bitmap(cf->glyphs);
            cf->glyphs = NULL;
        }

        if (!next && cf->glyphs)
            al_destroy_bitmap(cf->glyphs);

        al_free(cf->bitmaps);
        al_free(cf);

        cf = next;
    }

    al_free(f);
}


static int color_get_font_ranges(ALLEGRO_FONT *font, int ranges_count,
   int *ranges)
{
   ALLEGRO_FONT_COLOR_DATA *cf = font->data;
   int i = 0;
   while (cf) {
      if (i < ranges_count) {
         ranges[i * 2 + 0] = cf->begin;
         ranges[i * 2 + 1] = cf->end - 1;
      }
      i++;
      cf = cf->next;
   }
   return i;
}

static bool color_get_glyph_dimensions(ALLEGRO_FONT const *f,
   int codepoint, int *bbx, int *bby, int *bbw, int *bbh)
{   
   ALLEGRO_BITMAP *glyph = _al_font_color_find_glyph(f, codepoint);
   if(!glyph) {
      if (f->fallback) {
         return al_get_glyph_dimensions(f->fallback, codepoint,
            bbx, bby, bbw, bbh);
      }
      return false;
   }
   if (bbx) *bbx = 0;
   if (bby) *bby = 0;
   if (bbw) *bbw = glyph ? al_get_bitmap_width(glyph) : 0;
   if (bbh) *bbh = al_get_font_line_height(f);
   return true;
}

static int color_get_glyph_advance(ALLEGRO_FONT const *f,
   int codepoint1, int codepoint2)
{
   (void) codepoint2;
   
   /* Handle special case to simplify use in a loop. */
   if (codepoint1 == ALLEGRO_NO_KERNING) {
      return 0;
   }
      
   /* For other cases, bitmap fonts don't use any kerning, so just use the 
    * width of codepoint1. */
    
   return color_char_length(f, codepoint1);
}

/********
 * vtable declarations
 ********/

ALLEGRO_FONT_VTABLE _al_font_vtable_color = {
    font_height,
    font_ascent,
    font_descent,
    color_char_length,
    length,
    color_render_char,
    color_render,
    color_destroy,
    color_get_text_dimensions,
    color_get_font_ranges,
    color_get_glyph_dimensions,
    color_get_glyph_advance,
    color_get_glyph
};


static void font_shutdown(void)
{
    if (!font_inited)
       return;

    while (!_al_vector_is_empty(&font_handlers)) {
       FONT_HANDLER *h = _al_vector_ref_back(&font_handlers);
       al_ustr_free(h->extension);
       _al_vector_delete_at(&font_handlers, _al_vector_size(&font_handlers)-1);
    }
    _al_vector_free(&font_handlers);

    font_inited = false;
}


/* Function: al_init_font_addon
 */
bool al_init_font_addon(void)
{
   if (font_inited) {
      ALLEGRO_WARN("Font addon already initialised.\n");
      return true;
   }

   _al_vector_init(&font_handlers, sizeof(FONT_HANDLER));

   al_register_font_loader(".bmp", _al_load_bitmap_font);
   al_register_font_loader(".jpg", _al_load_bitmap_font);
   al_register_font_loader(".pcx", _al_load_bitmap_font);
   al_register_font_loader(".png", _al_load_bitmap_font);
   al_register_font_loader(".tga", _al_load_bitmap_font);

   al_register_font_loader(".xml", _al_load_bmfont_xml);
   al_register_font_loader(".fnt", _al_load_bmfont_xml);

   _al_add_exit_func(font_shutdown, "font_shutdown");

   font_inited = true;
   return font_inited;
}


/* Function: al_shutdown_font_addon
 */
void al_shutdown_font_addon(void)
{
   font_shutdown();
}


static FONT_HANDLER *find_extension(char const *extension)
{
   int i;
   /* Go backwards so a handler registered later for the same extension
    * has precedence.
    */
   for (i = _al_vector_size(&font_handlers) - 1; i >= 0 ; i--) {
      FONT_HANDLER *handler = _al_vector_ref(&font_handlers, i);
      if (0 == _al_stricmp(al_cstr(handler->extension), extension))
         return handler;
   }
   return NULL;
}



/* Function: al_register_font_loader
 */
bool al_register_font_loader(char const *extension,
   ALLEGRO_FONT *(*load_font)(char const *filename, int size, int flags))
{
   FONT_HANDLER *handler = find_extension(extension);
   if (!handler) {
      if (!load_font)
         return false; /* Nothing to remove. */
      handler = _al_vector_alloc_back(&font_handlers);
      handler->extension = al_ustr_new(extension);
   }
   else {
      if (!load_font) {
         al_ustr_free(handler->extension);
         return _al_vector_find_and_delete(&font_handlers, handler);
      }
   }
   handler->load_font = load_font;
   return true;
}



/* Function: al_load_font
 */
ALLEGRO_FONT *al_load_font(char const *filename, int size, int flags)
{
   int i;
   const char *ext;
   FONT_HANDLER *handler;

   ASSERT(filename);

   if (!font_inited) {
      ALLEGRO_ERROR("Font addon not initialised.\n");
      return NULL;
   }

   ext = strrchr(filename, '.');
   if (!ext) {
      ALLEGRO_ERROR("Unable to determine filetype: '%s'\n", filename);
      return NULL;
   }
   handler = find_extension(ext);
   if (handler)
      return handler->load_font(filename, size, flags);

   /* No handler for the extension was registered - try to load with
    * all registered font_handlers and see if one works. So if the user
    * does:
    *
    * al_init_font_addon()
    * al_init_ttf_addon()
    *
    * This will first try to load an unknown (let's say Type1) font file
    * with Freetype (and load it successfully in this case), then try
    * to load it as a bitmap font.
    */
   for (i = _al_vector_size(&font_handlers) - 1; i >= 0 ; i--) {
      FONT_HANDLER *handler = _al_vector_ref(&font_handlers, i);
      ALLEGRO_FONT *try = handler->load_font(filename, size, flags);
      if (try)
         return try;
   }

   return NULL;
}



/* Function: al_get_allegro_font_version
 */
uint32_t al_get_allegro_font_version(void)
{
   return ALLEGRO_VERSION_INT;
}

/* vim: set sts=4 sw=4 et: */