include/text/GP_Font.h

   1 /*****************************************************************************
   2  * This file is part of gfxprim library.                                     *
   3  *                                                                           *
   4  * Gfxprim is free software; you can redistribute it and/or                  *
   5  * modify it under the terms of the GNU Lesser General Public                *
   6  * License as published by the Free Software Foundation; either              *
   7  * version 2.1 of the License, or (at your option) any later version.        *
   8  *                                                                           *
   9  * Gfxprim is distributed in the hope that it will be useful,                *
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of            *
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU         *
  12  * Lesser General Public License for more details.                           *
  13  *                                                                           *
  14  * You should have received a copy of the GNU Lesser General Public          *
  15  * License along with gfxprim; if not, write to the Free Software            *
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor,                        *
  17  * Boston, MA  02110-1301  USA                                               *
  18  *                                                                           *
  19  * Copyright (C) 2009-2010 Jiri "BlueBear" Dluhos                            *
  20  *                         <jiri.bluebear.dluhos@gmail.com>                  *
  21  *                                                                           *
  22  * Copyright (C) 2009-2010 Cyril Hrubis <metan@ucw.cz>                       *
  23  *                                                                           *
  24  *****************************************************************************/
  25
  26 #ifndef GP_FONT_H
  27 #define GP_FONT_H
  28
  29 #include <stdint.h>
  30
  31 /* The smallest charset, covering only the 7-bit ASCII (0x20 .. 0x7f). */
  32 typedef enum GP_Charset {
  33         GP_CHARSET_7BIT = 1,
  34 } GP_Charset;
  35
  36 /* Maximum length of the font name, author, etc. (Note: these values are
  37  * used by the on-disc font format.)
  38  */
  39 #define GP_FONT_FAMILY_MAX      63
  40 #define GP_FONT_NAME_MAX        63
  41 #define GP_FONT_AUTHOR_MAX      63
  42 #define GP_FONT_LICENSE_MAX     15
  43
  44 /* The current version of the on-disc font format. */
  45 #define GP_FONT_FORMAT_VMAJOR   1
  46 #define GP_FONT_FORMAT_VMINOR   0
  47
  48 /* Magic string starting the on-disc font file. */
  49 #define GP_FONT_MAGIC           "# gfxprim font file"
  50
  51 /*
  52  * Contains font metadata.
  53  */
  54 typedef struct GP_Font {
  55
  56         /* Name of the font family. */
  57         char family[GP_FONT_NAME_MAX + 1];
  58
  59         /* Font name. */
  60         char name[GP_FONT_NAME_MAX + 1];
  61
  62         /* Name of the font author. */
  63         char author[GP_FONT_AUTHOR_MAX + 1];
  64
  65         /* Font license (default is "GPL2"). */
  66         char license[GP_FONT_LICENSE_MAX + 1];
  67
  68         /* Font version (incremented by font author when modifying the font data,
  69          * do not confuse with format version).
  70          */
  71         unsigned int version;
  72
  73         /* The charset specifies which characters are defined by the font. */
  74         uint8_t charset;
  75
  76
  77         /* Height of every character in pixels. */
  78         uint8_t height;
  79
  80         /* Height of the baseline (number of pixels from the bottom). */
  81         uint8_t baseline;
  82
  83         /*
  84          * Number of bytes for each pixel line in the character data
  85          * (typically 1/8 of char_width, rounded upwards).
  86          */
  87         uint8_t bytes_per_line;
  88
  89         /* Maximum width of the character bounding box (including empty areas
  90          * that are not drawn but cause other characters to shift).
  91          */
  92         uint8_t max_bounding_width;
  93
  94         /*
  95          * Array of GP_CharData structures, packed together sequentially
  96          * without padding.
  97          *
  98          * Characters are stored in encoding order. The first encoded character
  99          * is 0x20 (space). A font must, at a minimum, encode all characters
 100          * of the 7-bit ASCII set (0x20 .. 0x7F, inclusive).
 101          */
 102         uint8_t *data;
 103 } GP_Font;
 104
 105 #define GP_CHECK_FONT(font) do { \
 106         GP_CHECK(font->data, "invalid font: NULL font data"); \
 107         GP_CHECK(font->height > 0, "invalid font: height == 0"); \
 108         GP_CHECK(font->baseline <= font->height, "invalid font: baseline exceeds height"); \
 109         GP_CHECK(font->bytes_per_line > 0, "invalid font: bytes_per_line == 0"); \
 110 } while(0)
 111
 112 /* Data describing a single character. */
 113 typedef struct GP_CharData {
 114
 115         /* Width of the character in pixels. This is the area that is drawn
 116          * onto, but the real area occupied by the character can be different
 117          * and is defined by pre_offset and post_offset.
 118          */
 119         uint8_t char_width;
 120
 121         /* X offset to be applied to the current position *before*
 122          * drawing the character.
 123          */
 124         int8_t pre_offset;
 125
 126         /* X offset to be applied to the current position *after*
 127          * the character is drawn.
 128          */
 129         int8_t post_offset;
 130
 131         /* Character bitmap (size depends on width and height). */
 132         uint8_t bitmap[];
 133
 134 } GP_CharData;
 135
 136 /* The default font, which is hardcoded and always available. */
 137 extern struct GP_Font GP_default_console_font;
 138 extern struct GP_Font GP_default_proportional_font;
 139
 140 /* Returns the number of bytes occupied by the GP_CharData structure
 141  * for this font. (Currently, all characters occupy the same space
 142  * regardless of proportionality.)
 143  */
 144 unsigned int GP_GetCharDataSize(const GP_Font *font);
 145
 146 /* Returns a pointer to the character data (which start by the header)
 147  * of the specified character in the font data area.
 148  */
 149 const GP_CharData *GP_GetCharData(const GP_Font *font, int c);
 150
 151 /* Returns the overall size (in bytes) occupied by all characters
 152  * of the font (the font metadata do not count into this value;
 153  * add sizeof(GP_Font) to get the complete size of the font in memory.)
 154  */
 155 unsigned int GP_GetFontDataSize(const GP_Font *font);
 156
 157 #include "core/GP_RetCode.h"
 158
 159 GP_RetCode GP_FontLoad(GP_Font **font, const char *filename);
 160 GP_RetCode GP_FontSave(const GP_Font *font, const char *filename);
 161
 162 #endif /* GP_FONT_H */