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 program is free software; you can redistribute it and/or modify
   7   it under the terms of the GNU General Public License as published by
   8   the Free Software Foundation; either version 2 of the License, or
   9   (at your option) any later version.
  10
  11   This program is distributed in the hope that it will be useful,
  12   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14   GNU General Public License for more details.
  15
  16   You should have received a copy of the GNU General Public License
  17   along with this program; if not, write to the Free Software
  18   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  19 */
  20
  21 #include "config.h"
  22
  23 #include <inttypes.h>
  24 #include <ft2build.h>
  25 #include FT_FREETYPE_H
  26 #include FT_SYNTHESIS_H
  27 #include FT_GLYPH_H
  28 #include FT_TRUETYPE_TABLES_H
  29
  30 #include "ass.h"
  31 #include "ass_library.h"
  32 #include "ass_font.h"
  33 #include "ass_bitmap.h"
  34 #include "ass_cache.h"
  35 #include "ass_fontconfig.h"
  36 #include "ass_utils.h"
  37 #include "mputils.h"
  38
  39 /**
  40  * Select Microfost Unicode CharMap, if the font has one.
  41  * Otherwise, let FreeType decide.
  42  */
  43 static void charmap_magic(FT_Face face)
  44 {
  45         int i;
  46         for (i = 0; i < face->num_charmaps; ++i) {
  47                 FT_CharMap cmap = face->charmaps[i];
  48                 unsigned pid = cmap->platform_id;
  49                 unsigned eid = cmap->encoding_id;
  50                 if (pid == 3 /*microsoft*/ && (eid == 1 /*unicode bmp*/ || eid == 10 /*full unicode*/)) {
  51                         FT_Set_Charmap(face, cmap);
  52                         return;
  53                 }
  54         }
  55
  56         if (!face->charmap) {
  57                 if (face->num_charmaps == 0) {
  58                         mp_msg(MSGT_ASS, MSGL_WARN, MSGTR_LIBASS_NoCharmaps);
  59                         return;
  60                 }
  61                 mp_msg(MSGT_ASS, MSGL_WARN, MSGTR_LIBASS_NoCharmapAutodetected);
  62                 FT_Set_Charmap(face, face->charmaps[0]);
  63                 return;
  64         }
  65 }
  66
  67 static void update_transform(ass_font_t* font)
  68 {
  69         int i;
  70         FT_Matrix m;
  71         m.xx = double_to_d16(font->scale_x);
  72         m.yy = double_to_d16(font->scale_y);
  73         m.xy = m.yx = 0;
  74         for (i = 0; i < font->n_faces; ++i)
  75                 FT_Set_Transform(font->faces[i], &m, &font->v);
  76 }
  77
  78 /**
  79  * \brief find a memory font by name
  80  */
  81 static int find_font(ass_library_t* library, char* name)
  82 {
  83         int i;
  84         for (i = 0; i < library->num_fontdata; ++i)
  85                 if (strcasecmp(name, library->fontdata[i].name) == 0)
  86                         return i;
  87         return -1;
  88 }
  89
  90 static void face_set_size(FT_Face face, double size);
  91
  92 static void buggy_font_workaround(FT_Face face)
  93 {
  94         // Some fonts have zero Ascender/Descender fields in 'hhea' table.
  95         // In this case, get the information from 'os2' table or, as
  96         // a last resort, from face.bbox.
  97         if (face->ascender + face->descender == 0 || face->height == 0) {
  98                 TT_OS2 *os2 = FT_Get_Sfnt_Table(face, ft_sfnt_os2);
  99                 if (os2) {
 100                         face->ascender = os2->sTypoAscender;
 101                         face->descender = os2->sTypoDescender;
 102                         face->height = face->ascender - face->descender;
 103                 } else {
 104                         face->ascender = face->bbox.yMax;
 105                         face->descender = face->bbox.yMin;
 106                         face->height = face->ascender - face->descender;
 107                 }
 108         }
 109 }
 110
 111 /**
 112  * \brief Select a face with the given charcode and add it to ass_font_t
 113  * \return index of the new face in font->faces, -1 if failed
 114  */
 115 static int add_face(void* fc_priv, ass_font_t* font, uint32_t ch)
 116 {
 117         char* path;
 118         int index;
 119         FT_Face face;
 120         int error;
 121         int mem_idx;
 122
 123         if (font->n_faces == ASS_FONT_MAX_FACES)
 124                 return -1;
 125
 126         path = fontconfig_select(fc_priv, font->desc.family, font->desc.bold,
 127                                               font->desc.italic, &index, ch);
 128
 129         mem_idx = find_font(font->library, path);
 130         if (mem_idx >= 0) {
 131                 error = FT_New_Memory_Face(font->ftlibrary, (unsigned char*)font->library->fontdata[mem_idx].data,
 132                                            font->library->fontdata[mem_idx].size, 0, &face);
 133                 if (error) {
 134                         mp_msg(MSGT_ASS, MSGL_WARN, MSGTR_LIBASS_ErrorOpeningMemoryFont, path);
 135                         return -1;
 136                 }
 137         } else {
 138                 error = FT_New_Face(font->ftlibrary, path, index, &face);
 139                 if (error) {
 140                         mp_msg(MSGT_ASS, MSGL_WARN, MSGTR_LIBASS_ErrorOpeningFont, path, index);
 141                         return -1;
 142                 }
 143         }
 144         charmap_magic(face);
 145         buggy_font_workaround(face);
 146
 147         font->faces[font->n_faces++] = face;
 148         update_transform(font);
 149         face_set_size(face, font->size);
 150         return font->n_faces - 1;
 151 }
 152
 153 /**
 154  * \brief Create a new ass_font_t according to "desc" argument
 155  */
 156 ass_font_t* ass_font_new(ass_library_t* library, FT_Library ftlibrary, void* fc_priv, ass_font_desc_t* desc)
 157 {
 158         int error;
 159         ass_font_t* fontp;
 160         ass_font_t font;
 161
 162         fontp = ass_font_cache_find(desc);
 163         if (fontp)
 164                 return fontp;
 165
 166         font.library = library;
 167         font.ftlibrary = ftlibrary;
 168         font.n_faces = 0;
 169         font.desc.family = strdup(desc->family);
 170         font.desc.bold = desc->bold;
 171         font.desc.italic = desc->italic;
 172
 173         font.scale_x = font.scale_y = 1.;
 174         font.v.x = font.v.y = 0;
 175         font.size = 0.;
 176
 177         error = add_face(fc_priv, &font, 0);
 178         if (error == -1) {
 179                 free(font.desc.family);
 180                 return 0;
 181         } else
 182                 return ass_font_cache_add(&font);
 183 }
 184
 185 /**
 186  * \brief Set font transformation matrix and shift vector
 187  **/
 188 void ass_font_set_transform(ass_font_t* font, double scale_x, double scale_y, FT_Vector* v)
 189 {
 190         font->scale_x = scale_x;
 191         font->scale_y = scale_y;
 192         font->v.x = v->x;
 193         font->v.y = v->y;
 194         update_transform(font);
 195 }
 196
 197 static void face_set_size(FT_Face face, double size)
 198 {
 199 #if (FREETYPE_MAJOR > 2) || ((FREETYPE_MAJOR == 2) && (FREETYPE_MINOR > 1))
 200         TT_HoriHeader *hori = FT_Get_Sfnt_Table(face, ft_sfnt_hhea);
 201         TT_OS2 *os2 = FT_Get_Sfnt_Table(face, ft_sfnt_os2);
 202         double mscale = 1.;
 203         FT_Size_RequestRec rq;
 204         FT_Size_Metrics *m = &face->size->metrics;
 205         // VSFilter uses metrics from TrueType OS/2 table
 206         // The idea was borrowed from asa (http://asa.diac24.net)
 207         if (hori && os2) {
 208                 int hori_height = hori->Ascender - hori->Descender;
 209                 int os2_height = os2->usWinAscent + os2->usWinDescent;
 210                 if (hori_height && os2_height)
 211                         mscale = (double)hori_height / os2_height;
 212         }
 213         memset(&rq, 0, sizeof(rq));
 214         rq.type = FT_SIZE_REQUEST_TYPE_REAL_DIM;
 215         rq.width = 0;
 216         rq.height = double_to_d6(size * mscale);
 217         rq.horiResolution = rq.vertResolution = 0;
 218         FT_Request_Size(face, &rq);
 219         m->ascender /= mscale;
 220         m->descender /= mscale;
 221         m->height /= mscale;
 222 #else
 223         FT_Set_Char_Size(face, 0, double_to_d6(size), 0, 0);
 224 #endif
 225 }
 226
 227 /**
 228  * \brief Set font size
 229  **/
 230 void ass_font_set_size(ass_font_t* font, double size)
 231 {
 232         int i;
 233         if (font->size != size) {
 234                 font->size = size;
 235                 for (i = 0; i < font->n_faces; ++i)
 236                         face_set_size(font->faces[i], size);
 237         }
 238 }
 239
 240 /**
 241  * \brief Get maximal font ascender and descender.
 242  * \param ch character code
 243  * The values are extracted from the font face that provides glyphs for the given character
 244  **/
 245 void ass_font_get_asc_desc(ass_font_t* font, uint32_t ch, int* asc, int* desc)
 246 {
 247         int i;
 248         for (i = 0; i < font->n_faces; ++i) {
 249                 FT_Face face = font->faces[i];
 250                 if (FT_Get_Char_Index(face, ch)) {
 251                         int v, v2;
 252                         v = face->size->metrics.ascender;
 253                         v2 = FT_MulFix(face->bbox.yMax, face->size->metrics.y_scale);
 254                         *asc = (v > v2 * 0.9) ? v : v2;
 255
 256                         v = - face->size->metrics.descender;
 257                         v2 = - FT_MulFix(face->bbox.yMin, face->size->metrics.y_scale);
 258                         *desc = (v > v2 * 0.9) ? v : v2;
 259                         return;
 260                 }
 261         }
 262
 263         *asc = *desc = 0;
 264 }
 265
 266 /**
 267  * \brief Get a glyph
 268  * \param ch character code
 269  **/
 270 FT_Glyph ass_font_get_glyph(void* fontconfig_priv, ass_font_t* font, uint32_t ch, ass_hinting_t hinting)
 271 {
 272         int error;
 273         int index = 0;
 274         int i;
 275         FT_Glyph glyph;
 276         FT_Face face = 0;
 277         int flags = 0;
 278
 279         if (ch < 0x20)
 280                 return 0;
 281         if (font->n_faces == 0)
 282                 return 0;
 283
 284         for (i = 0; i < font->n_faces; ++i) {
 285                 face = font->faces[i];
 286                 index = FT_Get_Char_Index(face, ch);
 287                 if (index)
 288                         break;
 289         }
 290
 291 #ifdef HAVE_FONTCONFIG
 292         if (index == 0) {
 293                 int face_idx;
 294                 mp_msg(MSGT_ASS, MSGL_INFO, MSGTR_LIBASS_GlyphNotFoundReselectingFont,
 295                        ch, font->desc.family, font->desc.bold, font->desc.italic);
 296                 face_idx = add_face(fontconfig_priv, font, ch);
 297                 if (face_idx >= 0) {
 298                         face = font->faces[face_idx];
 299                         index = FT_Get_Char_Index(face, ch);
 300                         if (index == 0) {
 301                                 mp_msg(MSGT_ASS, MSGL_ERR, MSGTR_LIBASS_GlyphNotFound,
 302                                        ch, font->desc.family, font->desc.bold, font->desc.italic);
 303                         }
 304                 }
 305         }
 306 #endif
 307
 308         switch (hinting) {
 309         case ASS_HINTING_NONE: flags = FT_LOAD_NO_HINTING; break;
 310         case ASS_HINTING_LIGHT: flags = FT_LOAD_FORCE_AUTOHINT | FT_LOAD_TARGET_LIGHT; break;
 311         case ASS_HINTING_NORMAL: flags = FT_LOAD_FORCE_AUTOHINT; break;
 312         case ASS_HINTING_NATIVE: flags = 0; break;
 313         }
 314
 315         error = FT_Load_Glyph(face, index, FT_LOAD_NO_BITMAP | flags);
 316         if (error) {
 317                 mp_msg(MSGT_ASS, MSGL_WARN, MSGTR_LIBASS_ErrorLoadingGlyph);
 318                 return 0;
 319         }
 320
 321 #if (FREETYPE_MAJOR > 2) || \
 322     ((FREETYPE_MAJOR == 2) && (FREETYPE_MINOR >= 2)) || \
 323     ((FREETYPE_MAJOR == 2) && (FREETYPE_MINOR == 1) && (FREETYPE_PATCH >= 10))
 324 // FreeType >= 2.1.10 required
 325         if (!(face->style_flags & FT_STYLE_FLAG_ITALIC) &&
 326                         (font->desc.italic > 55)) {
 327                 FT_GlyphSlot_Oblique(face->glyph);
 328         }
 329 #endif
 330         error = FT_Get_Glyph(face->glyph, &glyph);
 331         if (error) {
 332                 mp_msg(MSGT_ASS, MSGL_WARN, MSGTR_LIBASS_ErrorLoadingGlyph);
 333                 return 0;
 334         }
 335
 336         return glyph;
 337 }
 338
 339 /**
 340  * \brief Get kerning for the pair of glyphs.
 341  **/
 342 FT_Vector ass_font_get_kerning(ass_font_t* font, uint32_t c1, uint32_t c2)
 343 {
 344         FT_Vector v = {0, 0};
 345         int i;
 346
 347         for (i = 0; i < font->n_faces; ++i) {
 348                 FT_Face face = font->faces[i];
 349                 int i1 = FT_Get_Char_Index(face, c1);
 350                 int i2 = FT_Get_Char_Index(face, c2);
 351                 if (i1 && i2) {
 352                         if (FT_HAS_KERNING(face))
 353                                 FT_Get_Kerning(face, i1, i2, FT_KERNING_DEFAULT, &v);
 354                         return v;
 355                 }
 356                 if (i1 || i2) // these glyphs are from different font faces, no kerning information
 357                         return v;
 358         }
 359         return v;
 360 }
 361
 362 /**
 363  * \brief Deallocate ass_font_t
 364  **/
 365 void ass_font_free(ass_font_t* font)
 366 {
 367         int i;
 368         for (i = 0; i < font->n_faces; ++i)
 369                 if (font->faces[i]) FT_Done_Face(font->faces[i]);
 370         if (font->desc.family) free(font->desc.family);
 371         free(font);
 372 }