src/os/unix/font_unix.cpp

   1 /*
   2  * This file is part of OpenTTD.
   3  * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
   4  * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   5  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
   6  */
   7
   8 /** @file font_unix.cpp Functions related to font handling on Unix/Fontconfig. */
   9
  10 #include "../../stdafx.h"
  11 #include "../../debug.h"
  12 #include "../../fontdetection.h"
  13 #include "../../string_func.h"
  14 #include "../../strings_func.h"
  15
  16 #include <fontconfig/fontconfig.h>
  17
  18 #include "safeguards.h"
  19
  20 #include <ft2build.h>
  21 #include FT_FREETYPE_H
  22
  23 extern FT_Library _library;
  24
  25 /**
  26  * Split the font name into the font family and style. These fields are separated by a comma,
  27  * but the style does not necessarily need to exist.
  28  * @param font_name The font name.
  29  * @return The font family and style.
  30  */
  31 static std::tuple<std::string, std::string> SplitFontFamilyAndStyle(std::string_view font_name)
  32 {
  33         auto separator = font_name.find(',');
  34         if (separator == std::string_view::npos) return { std::string(font_name), std::string() };
  35
  36         auto begin = font_name.find_first_not_of("\t ", separator + 1);
  37         if (begin == std::string_view::npos) return { std::string(font_name.substr(0, separator)), std::string() };
  38
  39         return { std::string(font_name.substr(0, separator)), std::string(font_name.substr(begin)) };
  40 }
  41
  42 FT_Error GetFontByFaceName(const char *font_name, FT_Face *face)
  43 {
  44         FT_Error err = FT_Err_Cannot_Open_Resource;
  45
  46         if (!FcInit()) {
  47                 ShowInfo("Unable to load font configuration");
  48                 return err;
  49         }
  50
  51         auto fc_instance = FcConfigReference(nullptr);
  52         assert(fc_instance != nullptr);
  53
  54         /* Split & strip the font's style */
  55         auto [font_family, font_style] = SplitFontFamilyAndStyle(font_name);
  56
  57         /* Resolve the name and populate the information structure */
  58         FcPattern *pat = FcNameParse((FcChar8 *)font_family.data());
  59         if (!font_style.empty()) FcPatternAddString(pat, FC_STYLE, (FcChar8 *)font_style.data());
  60         FcConfigSubstitute(nullptr, pat, FcMatchPattern);
  61         FcDefaultSubstitute(pat);
  62         FcFontSet *fs = FcFontSetCreate();
  63         FcResult  result;
  64         FcPattern *match = FcFontMatch(nullptr, pat, &result);
  65
  66         if (fs != nullptr && match != nullptr) {
  67                 FcChar8 *family;
  68                 FcChar8 *style;
  69                 FcChar8 *file;
  70                 int32_t index;
  71                 FcFontSetAdd(fs, match);
  72
  73                 for (int i = 0; err != FT_Err_Ok && i < fs->nfont; i++) {
  74                         /* Try the new filename */
  75                         if (FcPatternGetString(fs->fonts[i], FC_FILE, 0, &file) == FcResultMatch &&
  76                                 FcPatternGetString(fs->fonts[i], FC_FAMILY, 0, &family) == FcResultMatch &&
  77                                 FcPatternGetString(fs->fonts[i], FC_STYLE, 0, &style) == FcResultMatch &&
  78                                 FcPatternGetInteger(fs->fonts[i], FC_INDEX, 0, &index) == FcResultMatch) {
  79
  80                                 /* The correct style? */
  81                                 if (!font_style.empty() && !StrEqualsIgnoreCase(font_style, (char *)style)) continue;
  82
  83                                 /* Font config takes the best shot, which, if the family name is spelled
  84                                  * wrongly a 'random' font, so check whether the family name is the
  85                                  * same as the supplied name */
  86                                 if (StrEqualsIgnoreCase(font_family, (char *)family)) {
  87                                         err = FT_New_Face(_library, (char *)file, index, face);
  88                                 }
  89                         }
  90                 }
  91         }
  92
  93         FcPatternDestroy(pat);
  94         FcFontSetDestroy(fs);
  95         FcConfigDestroy(fc_instance);
  96
  97         return err;
  98 }
  99
 100 bool SetFallbackFont(FontCacheSettings *settings, const std::string &language_isocode, int, MissingGlyphSearcher *callback)
 101 {
 102         bool ret = false;
 103
 104         if (!FcInit()) return ret;
 105
 106         auto fc_instance = FcConfigReference(nullptr);
 107         assert(fc_instance != nullptr);
 108
 109         /* Fontconfig doesn't handle full language isocodes, only the part
 110          * before the _ of e.g. en_GB is used, so "remove" everything after
 111          * the _. */
 112         std::string lang = fmt::format(":lang={}", language_isocode.substr(0, language_isocode.find('_')));
 113
 114         /* First create a pattern to match the wanted language. */
 115         FcPattern *pat = FcNameParse((const FcChar8 *)lang.c_str());
 116         /* We only want to know these attributes. */
 117         FcObjectSet *os = FcObjectSetBuild(FC_FILE, FC_INDEX, FC_SPACING, FC_SLANT, FC_WEIGHT, nullptr);
 118         /* Get the list of filenames matching the wanted language. */
 119         FcFontSet *fs = FcFontList(nullptr, pat, os);
 120
 121         /* We don't need these anymore. */
 122         FcObjectSetDestroy(os);
 123         FcPatternDestroy(pat);
 124
 125         if (fs != nullptr) {
 126                 int best_weight = -1;
 127                 const char *best_font = nullptr;
 128                 int best_index = 0;
 129
 130                 for (int i = 0; i < fs->nfont; i++) {
 131                         FcPattern *font = fs->fonts[i];
 132
 133                         FcChar8 *file = nullptr;
 134                         FcResult res = FcPatternGetString(font, FC_FILE, 0, &file);
 135                         if (res != FcResultMatch || file == nullptr) {
 136                                 continue;
 137                         }
 138
 139                         /* Get a font with the right spacing .*/
 140                         int value = 0;
 141                         FcPatternGetInteger(font, FC_SPACING, 0, &value);
 142                         if (callback->Monospace() != (value == FC_MONO) && value != FC_DUAL) continue;
 143
 144                         /* Do not use those that explicitly say they're slanted. */
 145                         FcPatternGetInteger(font, FC_SLANT, 0, &value);
 146                         if (value != 0) continue;
 147
 148                         /* We want the fatter font as they look better at small sizes. */
 149                         FcPatternGetInteger(font, FC_WEIGHT, 0, &value);
 150                         if (value <= best_weight) continue;
 151
 152                         /* Possible match based on attributes, get index. */
 153                         int32_t index;
 154                         res = FcPatternGetInteger(font, FC_INDEX, 0, &index);
 155                         if (res != FcResultMatch) continue;
 156
 157                         callback->SetFontNames(settings, (const char *)file, &index);
 158
 159                         bool missing = callback->FindMissingGlyphs();
 160                         Debug(fontcache, 1, "Font \"{}\" misses{} glyphs", (char *)file, missing ? "" : " no");
 161
 162                         if (!missing) {
 163                                 best_weight = value;
 164                                 best_font = (const char *)file;
 165                                 best_index = index;
 166                         }
 167                 }
 168
 169                 if (best_font != nullptr) {
 170                         ret = true;
 171                         callback->SetFontNames(settings, best_font, &best_index);
 172                         InitFontCache(callback->Monospace());
 173                 }
 174
 175                 /* Clean up the list of filenames. */
 176                 FcFontSetDestroy(fs);
 177         }
 178
 179         FcConfigDestroy(fc_instance);
 180         return ret;
 181 }