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annotate libs/drawtext/drawtext.h @ 0:b2f14e535253

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author John Tsiombikas <nuclear@member.fsf.org>
date Sat, 01 Feb 2014 19:58:19 +0200
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nuclear@0 1 /*
nuclear@0 2 libdrawtext - a simple library for fast text rendering in OpenGL
nuclear@0 3 Copyright (C) 2011-2012 John Tsiombikas <nuclear@member.fsf.org>
nuclear@0 4
nuclear@0 5 This program is free software: you can redistribute it and/or modify
nuclear@0 6 it under the terms of the GNU Lesser General Public License as published by
nuclear@0 7 the Free Software Foundation, either version 3 of the License, or
nuclear@0 8 (at your option) any later version.
nuclear@0 9
nuclear@0 10 This program is distributed in the hope that it will be useful,
nuclear@0 11 but WITHOUT ANY WARRANTY; without even the implied warranty of
nuclear@0 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
nuclear@0 13 GNU Lesser General Public License for more details.
nuclear@0 14
nuclear@0 15 You should have received a copy of the GNU Lesser General Public License
nuclear@0 16 along with this program. If not, see <http://www.gnu.org/licenses/>.
nuclear@0 17 */
nuclear@0 18 #ifndef TEXT_H_
nuclear@0 19 #define TEXT_H_
nuclear@0 20
nuclear@0 21 #include <stdio.h>
nuclear@0 22 #include <stdlib.h>
nuclear@0 23
nuclear@0 24 struct dtx_font;
nuclear@0 25 struct dtx_glyphmap;
nuclear@0 26
nuclear@0 27 /* draw buffering modes */
nuclear@0 28 enum {
nuclear@0 29 DTX_NBF, /* unbuffered */
nuclear@0 30 DTX_LBF, /* line buffered */
nuclear@0 31 DTX_FBF /* fully buffered */
nuclear@0 32 };
nuclear@0 33
nuclear@0 34 struct dtx_box {
nuclear@0 35 float x, y;
nuclear@0 36 float width, height;
nuclear@0 37 };
nuclear@0 38
nuclear@0 39 #ifdef __cplusplus
nuclear@0 40 extern "C" {
nuclear@0 41 #endif
nuclear@0 42
nuclear@0 43 /* Open a truetype/opentype/whatever font.
nuclear@0 44 *
nuclear@0 45 * If sz is non-zero, the default ASCII glyphmap at the requested point size is
nuclear@0 46 * automatically created as well, and ready to use.
nuclear@0 47 *
nuclear@0 48 * To use other unicode ranges and different font sizes you must first call
nuclear@0 49 * dtx_prepare or dtx_prepare_range before issuing any drawing calls, otherwise
nuclear@0 50 * nothing will be rendered.
nuclear@0 51 */
nuclear@0 52 struct dtx_font *dtx_open_font(const char *fname, int sz);
nuclear@0 53 void dtx_close_font(struct dtx_font *fnt);
nuclear@0 54
nuclear@0 55 /* prepare an ASCII glyphmap for the specified font size */
nuclear@0 56 void dtx_prepare(struct dtx_font *fnt, int sz);
nuclear@0 57 /* prepare an arbitrary unicode range glyphmap for the specified font size */
nuclear@0 58 void dtx_prepare_range(struct dtx_font *fnt, int sz, int cstart, int cend);
nuclear@0 59
nuclear@0 60 /* Finds the glyphmap that contains the specified character code and matches the requested size
nuclear@0 61 * Returns null if it hasn't been created (you should call dtx_prepare/dtx_prepare_range).
nuclear@0 62 */
nuclear@0 63 struct dtx_glyphmap *dtx_get_font_glyphmap(struct dtx_font *fnt, int sz, int code);
nuclear@0 64
nuclear@0 65 /* Finds the glyphmap that contains the specified unicode range and matches the requested font size
nuclear@0 66 * Will automatically generate one if it can't find it.
nuclear@0 67 */
nuclear@0 68 struct dtx_glyphmap *dtx_get_font_glyphmap_range(struct dtx_font *fnt, int sz, int cstart, int cend);
nuclear@0 69
nuclear@0 70 /* Creates and returns a glyphmap for a particular unicode range and font size.
nuclear@0 71 * The generated glyphmap is added to the font's list of glyphmaps.
nuclear@0 72 */
nuclear@0 73 struct dtx_glyphmap *dtx_create_glyphmap_range(struct dtx_font *fnt, int sz, int cstart, int cend);
nuclear@0 74 /* free a glyphmap */
nuclear@0 75 void dtx_free_glyphmap(struct dtx_glyphmap *gmap);
nuclear@0 76
nuclear@0 77 /* returns a pointer to the raster image of a glyphmap (1 byte per pixel grayscale) */
nuclear@0 78 unsigned char *dtx_get_glyphmap_image(struct dtx_glyphmap *gmap);
nuclear@0 79 /* returns the width of the glyphmap image in pixels */
nuclear@0 80 int dtx_get_glyphmap_width(struct dtx_glyphmap *gmap);
nuclear@0 81 /* returns the height of the glyphmap image in pixels */
nuclear@0 82 int dtx_get_glyphmap_height(struct dtx_glyphmap *gmap);
nuclear@0 83
nuclear@0 84 /* The following functions can be used even when the library is compiled without
nuclear@0 85 * freetype support. (TODO)
nuclear@0 86 */
nuclear@0 87 struct dtx_glyphmap *dtx_load_glyphmap(const char *fname);
nuclear@0 88 struct dtx_glyphmap *dtx_load_glyphmap_stream(FILE *fp);
nuclear@0 89 int dtx_save_glyphmap(const char *fname, const struct dtx_glyphmap *gmap);
nuclear@0 90 int dtx_save_glyphmap_stream(FILE *fp, const struct dtx_glyphmap *gmap);
nuclear@0 91
nuclear@0 92
nuclear@0 93 /* ---- rendering ---- */
nuclear@0 94
nuclear@0 95 /* before drawing anything this function must set the font to use */
nuclear@0 96 void dtx_use_font(struct dtx_font *fnt, int sz);
nuclear@0 97
nuclear@0 98 /* sets the buffering mode
nuclear@0 99 * - DTX_NBF: every call to dtx_string gets rendered immediately.
nuclear@0 100 * - DTX_LBF: renders when the buffer is full or the string contains a newline.
nuclear@0 101 * - DTX_FBF: renders only when the buffer is full (you must call dtx_flush explicitly).
nuclear@0 102 */
nuclear@0 103 void dtx_draw_buffering(int mode);
nuclear@0 104
nuclear@0 105 /* Sets the vertex attribute indices to use for passing vertex and texture coordinate
nuclear@0 106 * data. By default both are -1 which means you don't have to use a shader, and if you
nuclear@0 107 * do they are accessible through gl_Vertex and gl_MultiTexCoord0, as usual.
nuclear@0 108 *
nuclear@0 109 * NOTE: If you are using OpenGL ES 2.x or OpenGL >= 3.1 pure (non-compatibility) context
nuclear@0 110 * you must specify valid attribute indices.
nuclear@0 111 */
nuclear@0 112 void dtx_vertex_attribs(int vert_attr, int tex_attr);
nuclear@0 113
nuclear@0 114 /* draws a single glyph at the origin */
nuclear@0 115 void dtx_glyph(int code);
nuclear@0 116 /* draws a utf-8 string starting at the origin. \n \r and \t are handled appropriately. */
nuclear@0 117 void dtx_string(const char *str);
nuclear@0 118
nuclear@0 119 void dtx_printf(const char *fmt, ...);
nuclear@0 120
nuclear@0 121 /* render any pending glyphs (see dtx_draw_buffering) */
nuclear@0 122 void dtx_flush(void);
nuclear@0 123
nuclear@0 124
nuclear@0 125 /* ---- encodings ---- */
nuclear@0 126
nuclear@0 127 /* returns a pointer to the next character in a utf-8 stream */
nuclear@0 128 char *dtx_utf8_next_char(char *str);
nuclear@0 129
nuclear@0 130 /* returns the unicode character codepoint of the utf-8 character starting at str */
nuclear@0 131 int dtx_utf8_char_code(const char *str);
nuclear@0 132
nuclear@0 133 /* returns the number of bytes of the utf-8 character starting at str */
nuclear@0 134 int dtx_utf8_nbytes(const char *str);
nuclear@0 135
nuclear@0 136 /* returns the number of utf-8 character in a zero-terminated utf-8 string */
nuclear@0 137 int dtx_utf8_char_count(const char *str);
nuclear@0 138
nuclear@0 139 /* Converts a unicode code-point to a utf-8 character by filling in the buffer
nuclear@0 140 * passed at the second argument, and returns the number of bytes taken by that
nuclear@0 141 * utf-8 character.
nuclear@0 142 * It's valid to pass a null buffer pointer, in which case only the byte count is
nuclear@0 143 * returned (useful to figure out how much memory to allocate for a buffer).
nuclear@0 144 */
nuclear@0 145 size_t dtx_utf8_from_char_code(int code, char *buf);
nuclear@0 146
nuclear@0 147 /* Converts a unicode utf-16 wchar_t string to utf-8, filling in the buffer passed
nuclear@0 148 * at the second argument. Returns the size of the resulting string in bytes.
nuclear@0 149 *
nuclear@0 150 * It's valid to pass a null buffer pointer, in which case only the size gets
nuclear@0 151 * calculated and returned, which is useful for figuring out how much memory to
nuclear@0 152 * allocate for the utf-8 buffer.
nuclear@0 153 */
nuclear@0 154 size_t dtx_utf8_from_string(const wchar_t *str, char *buf);
nuclear@0 155
nuclear@0 156
nuclear@0 157 /* ---- metrics ---- */
nuclear@0 158 float dtx_line_height(void);
nuclear@0 159 float dtx_baseline(void);
nuclear@0 160
nuclear@0 161 /* rendered dimensions of a single glyph */
nuclear@0 162 void dtx_glyph_box(int code, struct dtx_box *box);
nuclear@0 163 float dtx_glyph_width(int code);
nuclear@0 164 float dtx_glyph_height(int code);
nuclear@0 165
nuclear@0 166 /* rendered dimensions of a string */
nuclear@0 167 void dtx_string_box(const char *str, struct dtx_box *box);
nuclear@0 168 float dtx_string_width(const char *str);
nuclear@0 169 float dtx_string_height(const char *str);
nuclear@0 170
nuclear@0 171 /* returns the horizontal position of the n-th character of the rendered string
nuclear@0 172 * (useful for placing cursors)
nuclear@0 173 */
nuclear@0 174 float dtx_char_pos(const char *str, int n);
nuclear@0 175
nuclear@0 176 int dtx_char_at_pt(const char *str, float pt);
nuclear@0 177
nuclear@0 178 #ifdef __cplusplus
nuclear@0 179 }
nuclear@0 180 #endif
nuclear@0 181
nuclear@0 182 #endif /* TEXT_H_ */