libass/ass_font.c

   1 // -*- c-basic-offset: 8; indent-tabs-mode: t -*-
   2 // vim:ts=8:sw=8:noet:ai:
   3 /*
   4  * Copyright (C) 2006 Evgeniy Stepanov <eugeni.stepanov@gmail.com>
   5  *
   6  * This file is part of libass.
   7  *
   8  * libass is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * libass is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with libass; if not, write to the Free Software Foundation, Inc.,
  20  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21  */
  22
  23 #include "config.h"
  24
  25 #include <inttypes.h>
  26 #include <ft2build.h>
  27 #include FT_FREETYPE_H
  28 #include FT_SYNTHESIS_H
  29 #include FT_GLYPH_H
  30 #include FT_TRUETYPE_TABLES_H
  31
  32 #include "ass.h"
  33 #include "ass_library.h"
  34 #include "ass_font.h"
  35 #include "ass_bitmap.h"
  36 #include "ass_cache.h"
  37 #include "ass_fontconfig.h"
  38 #include "ass_utils.h"
  39 #include "mputils.h"
  40
  41 /**
  42  * Select Microfost Unicode CharMap, if the font has one.
  43  * Otherwise, let FreeType decide.
  44  */
  45 static void charmap_magic(FT_Face face)
  46 {
  47         int i;
  48         for (i = 0; i < face->num_charmaps; ++i) {
  49                 FT_CharMap cmap = face->charmaps[i];
  50                 unsigned pid = cmap->platform_id;
  51                 unsigned eid = cmap->encoding_id;
  52                 if (pid == 3 /*microsoft*/ && (eid == 1 /*unicode bmp*/ || eid == 10 /*full unicode*/)) {
  53                         FT_Set_Charmap(face, cmap);
  54                         return;
  55                 }
  56         }
  57
  58         if (!face->charmap) {
  59                 if (face->num_charmaps == 0) {
  60                         mp_msg(MSGT_ASS, MSGL_WARN, MSGTR_LIBASS_NoCharmaps);
  61                         return;
  62                 }
  63                 mp_msg(MSGT_ASS, MSGL_WARN, MSGTR_LIBASS_NoCharmapAutodetected);
  64                 FT_Set_Charmap(face, face->charmaps[0]);
  65                 return;
  66         }
  67 }
  68
  69 static void update_transform(ass_font_t* font)
  70 {
  71         int i;
  72         FT_Matrix m;
  73         m.xx = double_to_d16(font->scale_x);
  74         m.yy = double_to_d16(font->scale_y);
  75         m.xy = m.yx = 0;
  76         for (i = 0; i < font->n_faces; ++i)
  77                 FT_Set_Transform(font->faces[i], &m, &font->v);
  78 }
  79
  80 /**
  81  * \brief find a memory font by name
  82  */
  83 static int find_font(ass_library_t* library, char* name)
  84 {
  85         int i;
  86         for (i = 0; i < library->num_fontdata; ++i)
  87                 if (strcasecmp(name, library->fontdata[i].name) == 0)
  88                         return i;
  89         return -1;
  90 }
  91
  92 static void face_set_size(FT_Face face, double size);
  93
  94 static void buggy_font_workaround(FT_Face face)
  95 {
  96         // Some fonts have zero Ascender/Descender fields in 'hhea' table.
  97         // In this case, get the information from 'os2' table or, as
  98         // a last resort, from face.bbox.
  99         if (face->ascender + face->descender == 0 || face->height == 0) {
 100                 TT_OS2 *os2 = FT_Get_Sfnt_Table(face, ft_sfnt_os2);
 101                 if (os2) {
 102                         face->ascender = os2->sTypoAscender;
 103                         face->descender = os2->sTypoDescender;
 104                         face->height = face->ascender - face->descender;
 105                 } else {
 106                         face->ascender = face->bbox.yMax;
 107                         face->descender = face->bbox.yMin;
 108                         face->height = face->ascender - face->descender;
 109                 }
 110         }
 111 }
 112
 113 /**
 114  * \brief Select a face with the given charcode and add it to ass_font_t
 115  * \return index of the new face in font->faces, -1 if failed
 116  */
 117 static int add_face(void* fc_priv, ass_font_t* font, uint32_t ch)
 118 {
 119         char* path;
 120         int index;
 121         FT_Face face;
 122         int error;
 123         int mem_idx;
 124
 125         if (font->n_faces == ASS_FONT_MAX_FACES)
 126                 return -1;
 127
 128         path = fontconfig_select(fc_priv, font->desc.family, font->desc.bold,
 129                                               font->desc.italic, &index, ch);
 130
 131         mem_idx = find_font(font->library, path);
 132         if (mem_idx >= 0) {
 133                 error = FT_New_Memory_Face(font->ftlibrary, (unsigned char*)font->library->fontdata[mem_idx].data,
 134                                            font->library->fontdata[mem_idx].size, 0, &face);
 135                 if (error) {
 136                         mp_msg(MSGT_ASS, MSGL_WARN, MSGTR_LIBASS_ErrorOpeningMemoryFont, path);
 137                         return -1;
 138                 }
 139         } else {
 140                 error = FT_New_Face(font->ftlibrary, path, index, &face);
 141                 if (error) {
 142                         mp_msg(MSGT_ASS, MSGL_WARN, MSGTR_LIBASS_ErrorOpeningFont, path, index);
 143                         return -1;
 144                 }
 145         }
 146         charmap_magic(face);
 147         buggy_font_workaround(face);
 148
 149         font->faces[font->n_faces++] = face;
 150         update_transform(font);
 151         face_set_size(face, font->size);
 152         return font->n_faces - 1;
 153 }
 154
 155 /**
 156  * \brief Create a new ass_font_t according to "desc" argument
 157  */
 158 ass_font_t* ass_font_new(ass_library_t* library, FT_Library ftlibrary, void* fc_priv, ass_font_desc_t* desc)
 159 {
 160         int error;
 161         ass_font_t* fontp;
 162         ass_font_t font;
 163
 164         fontp = ass_font_cache_find(desc);
 165         if (fontp)
 166                 return fontp;
 167
 168         font.library = library;
 169         font.ftlibrary = ftlibrary;
 170         font.n_faces = 0;
 171         font.desc.family = strdup(desc->family);
 172         font.desc.bold = desc->bold;
 173         font.desc.italic = desc->italic;
 174
 175         font.scale_x = font.scale_y = 1.;
 176         font.v.x = font.v.y = 0;
 177         font.size = 0.;
 178
 179         error = add_face(fc_priv, &font, 0);
 180         if (error == -1) {
 181                 free(font.desc.family);
 182                 return 0;
 183         } else
 184                 return ass_font_cache_add(&font);
 185 }
 186
 187 /**
 188  * \brief Set font transformation matrix and shift vector
 189  **/
 190 void ass_font_set_transform(ass_font_t* font, double scale_x, double scale_y, FT_Vector* v)
 191 {
 192         font->scale_x = scale_x;
 193         font->scale_y = scale_y;
 194         font->v.x = v->x;
 195         font->v.y = v->y;
 196         update_transform(font);
 197 }
 198
 199 static void face_set_size(FT_Face face, double size)
 200 {
 201 #if (FREETYPE_MAJOR > 2) || ((FREETYPE_MAJOR == 2) && (FREETYPE_MINOR > 1))
 202         TT_HoriHeader *hori = FT_Get_Sfnt_Table(face, ft_sfnt_hhea);
 203         TT_OS2 *os2 = FT_Get_Sfnt_Table(face, ft_sfnt_os2);
 204         double mscale = 1.;
 205         FT_Size_RequestRec rq;
 206         FT_Size_Metrics *m = &face->size->metrics;
 207         // VSFilter uses metrics from TrueType OS/2 table
 208         // The idea was borrowed from asa (http://asa.diac24.net)
 209         if (hori && os2) {
 210                 int hori_height = hori->Ascender - hori->Descender;
 211                 int os2_height = os2->usWinAscent + os2->usWinDescent;
 212                 if (hori_height && os2_height)
 213                         mscale = (double)hori_height / os2_height;
 214         }
 215         memset(&rq, 0, sizeof(rq));
 216         rq.type = FT_SIZE_REQUEST_TYPE_REAL_DIM;
 217         rq.width = 0;
 218         rq.height = double_to_d6(size * mscale);
 219         rq.horiResolution = rq.vertResolution = 0;
 220         FT_Request_Size(face, &rq);
 221         m->ascender /= mscale;
 222         m->descender /= mscale;
 223         m->height /= mscale;
 224 #else
 225         FT_Set_Char_Size(face, 0, double_to_d6(size), 0, 0);
 226 #endif
 227 }
 228
 229 /**
 230  * \brief Set font size
 231  **/
 232 void ass_font_set_size(ass_font_t* font, double size)
 233 {
 234         int i;
 235         if (font->size != size) {
 236                 font->size = size;
 237                 for (i = 0; i < font->n_faces; ++i)
 238                         face_set_size(font->faces[i], size);
 239         }
 240 }
 241
 242 /**
 243  * \brief Get maximal font ascender and descender.
 244  * \param ch character code
 245  * The values are extracted from the font face that provides glyphs for the given character
 246  **/
 247 void ass_font_get_asc_desc(ass_font_t* font, uint32_t ch, int* asc, int* desc)
 248 {
 249         int i;
 250         for (i = 0; i < font->n_faces; ++i) {
 251                 FT_Face face = font->faces[i];
 252                 if (FT_Get_Char_Index(face, ch)) {
 253                         *asc = face->size->metrics.ascender;
 254                         *desc = - face->size->metrics.descender;
 255                         return;
 256                 }
 257         }
 258
 259         *asc = *desc = 0;
 260 }
 261
 262 /**
 263  * \brief Get a glyph
 264  * \param ch character code
 265  **/
 266 FT_Glyph ass_font_get_glyph(void* fontconfig_priv, ass_font_t* font, uint32_t ch, ass_hinting_t hinting)
 267 {
 268         int error;
 269         int index = 0;
 270         int i;
 271         FT_Glyph glyph;
 272         FT_Face face = 0;
 273         int flags = 0;
 274
 275         if (ch < 0x20)
 276                 return 0;
 277         if (font->n_faces == 0)
 278                 return 0;
 279
 280         for (i = 0; i < font->n_faces; ++i) {
 281                 face = font->faces[i];
 282                 index = FT_Get_Char_Index(face, ch);
 283                 if (index)
 284                         break;
 285         }
 286
 287 #ifdef CONFIG_FONTCONFIG
 288         if (index == 0) {
 289                 int face_idx;
 290                 mp_msg(MSGT_ASS, MSGL_INFO, MSGTR_LIBASS_GlyphNotFoundReselectingFont,
 291                        ch, font->desc.family, font->desc.bold, font->desc.italic);
 292                 face_idx = add_face(fontconfig_priv, font, ch);
 293                 if (face_idx >= 0) {
 294                         face = font->faces[face_idx];
 295                         index = FT_Get_Char_Index(face, ch);
 296                         if (index == 0) {
 297                                 mp_msg(MSGT_ASS, MSGL_ERR, MSGTR_LIBASS_GlyphNotFound,
 298                                        ch, font->desc.family, font->desc.bold, font->desc.italic);
 299                         }
 300                 }
 301         }
 302 #endif
 303
 304         switch (hinting) {
 305         case ASS_HINTING_NONE: flags = FT_LOAD_NO_HINTING; break;
 306         case ASS_HINTING_LIGHT: flags = FT_LOAD_FORCE_AUTOHINT | FT_LOAD_TARGET_LIGHT; break;
 307         case ASS_HINTING_NORMAL: flags = FT_LOAD_FORCE_AUTOHINT; break;
 308         case ASS_HINTING_NATIVE: flags = 0; break;
 309         }
 310
 311         error = FT_Load_Glyph(face, index, FT_LOAD_NO_BITMAP | flags);
 312         if (error) {
 313                 mp_msg(MSGT_ASS, MSGL_WARN, MSGTR_LIBASS_ErrorLoadingGlyph);
 314                 return 0;
 315         }
 316
 317 #if (FREETYPE_MAJOR > 2) || \
 318     ((FREETYPE_MAJOR == 2) && (FREETYPE_MINOR >= 2)) || \
 319     ((FREETYPE_MAJOR == 2) && (FREETYPE_MINOR == 1) && (FREETYPE_PATCH >= 10))
 320 // FreeType >= 2.1.10 required
 321         if (!(face->style_flags & FT_STYLE_FLAG_ITALIC) &&
 322                         (font->desc.italic > 55)) {
 323                 FT_GlyphSlot_Oblique(face->glyph);
 324         }
 325 #endif
 326         error = FT_Get_Glyph(face->glyph, &glyph);
 327         if (error) {
 328                 mp_msg(MSGT_ASS, MSGL_WARN, MSGTR_LIBASS_ErrorLoadingGlyph);
 329                 return 0;
 330         }
 331
 332         return glyph;
 333 }
 334
 335 /**
 336  * \brief Get kerning for the pair of glyphs.
 337  **/
 338 FT_Vector ass_font_get_kerning(ass_font_t* font, uint32_t c1, uint32_t c2)
 339 {
 340         FT_Vector v = {0, 0};
 341         int i;
 342
 343         for (i = 0; i < font->n_faces; ++i) {
 344                 FT_Face face = font->faces[i];
 345                 int i1 = FT_Get_Char_Index(face, c1);
 346                 int i2 = FT_Get_Char_Index(face, c2);
 347                 if (i1 && i2) {
 348                         if (FT_HAS_KERNING(face))
 349                                 FT_Get_Kerning(face, i1, i2, FT_KERNING_DEFAULT, &v);
 350                         return v;
 351                 }
 352                 if (i1 || i2) // these glyphs are from different font faces, no kerning information
 353                         return v;
 354         }
 355         return v;
 356 }
 357
 358 /**
 359  * \brief Deallocate ass_font_t
 360  **/
 361 void ass_font_free(ass_font_t* font)
 362 {
 363         int i;
 364         for (i = 0; i < font->n_faces; ++i)
 365                 if (font->faces[i]) FT_Done_Face(font->faces[i]);
 366         if (font->desc.family) free(font->desc.family);
 367         free(font);
 368 }