gfx/thebes/gfxFT2Utils.cpp

   1 /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  * This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #include "gfxFT2FontBase.h"
   7 #include "gfxFT2Utils.h"
   8 #include "mozilla/Likely.h"
   9
  10 #ifdef HAVE_FONTCONFIG_FCFREETYPE_H
  11 #  include <fontconfig/fcfreetype.h>
  12 #endif
  13
  14 #include "ft2build.h"
  15 #include FT_MULTIPLE_MASTERS_H
  16
  17 #include "prlink.h"
  18
  19 uint32_t gfxFT2LockedFace::GetGlyph(uint32_t aCharCode) {
  20   if (MOZ_UNLIKELY(!mFace)) return 0;
  21
  22 #ifdef HAVE_FONTCONFIG_FCFREETYPE_H
  23   // FcFreeTypeCharIndex will search starting from the most recently
  24   // selected charmap.  This can cause non-determistic behavior when more
  25   // than one charmap supports a character but with different glyphs, as
  26   // with older versions of MS Gothic, for example.  Always prefer a Unicode
  27   // charmap, if there is one; failing that, try MS_SYMBOL.
  28   // (FcFreeTypeCharIndex usually does the appropriate Unicode conversion,
  29   // but some fonts have non-Roman glyphs for FT_ENCODING_APPLE_ROMAN
  30   // characters.)
  31   if (!mFace->charmap || (mFace->charmap->encoding != FT_ENCODING_UNICODE &&
  32                           mFace->charmap->encoding != FT_ENCODING_MS_SYMBOL)) {
  33     if (FT_Err_Ok != FT_Select_Charmap(mFace, FT_ENCODING_UNICODE) &&
  34         FT_Err_Ok != FT_Select_Charmap(mFace, FT_ENCODING_MS_SYMBOL)) {
  35       NS_WARNING("failed to select Unicode or symbol charmap");
  36     }
  37   }
  38
  39   return FcFreeTypeCharIndex(mFace, aCharCode);
  40 #else
  41   return FT_Get_Char_Index(mFace, aCharCode);
  42 #endif
  43 }
  44
  45 typedef FT_UInt (*GetCharVariantFunction)(FT_Face face, FT_ULong charcode,
  46                                           FT_ULong variantSelector);
  47
  48 uint32_t gfxFT2LockedFace::GetUVSGlyph(uint32_t aCharCode,
  49                                        uint32_t aVariantSelector) {
  50   MOZ_ASSERT(aVariantSelector, "aVariantSelector should not be NULL");
  51
  52   if (MOZ_UNLIKELY(!mFace)) return 0;
  53
  54   // This function is available from FreeType 2.3.6 (June 2008).
  55   static CharVariantFunction sGetCharVariantPtr = FindCharVariantFunction();
  56   if (!sGetCharVariantPtr) return 0;
  57
  58 #ifdef HAVE_FONTCONFIG_FCFREETYPE_H
  59   // FcFreeTypeCharIndex may have changed the selected charmap.
  60   // FT_Face_GetCharVariantIndex needs a unicode charmap.
  61   if (!mFace->charmap || mFace->charmap->encoding != FT_ENCODING_UNICODE) {
  62     FT_Select_Charmap(mFace, FT_ENCODING_UNICODE);
  63   }
  64 #endif
  65
  66   return (*sGetCharVariantPtr)(mFace, aCharCode, aVariantSelector);
  67 }
  68
  69 gfxFT2LockedFace::CharVariantFunction
  70 gfxFT2LockedFace::FindCharVariantFunction() {
  71   // This function is available from FreeType 2.3.6 (June 2008).
  72   PRLibrary* lib = nullptr;
  73   CharVariantFunction function = reinterpret_cast<CharVariantFunction>(
  74       PR_FindFunctionSymbolAndLibrary("FT_Face_GetCharVariantIndex", &lib));
  75   if (!lib) {
  76     return nullptr;
  77   }
  78
  79   FT_Int major;
  80   FT_Int minor;
  81   FT_Int patch;
  82   FT_Library_Version(mFace->glyph->library, &major, &minor, &patch);
  83
  84   // Versions 2.4.0 to 2.4.3 crash if configured with
  85   // FT_CONFIG_OPTION_OLD_INTERNALS.  Presence of the symbol FT_Alloc
  86   // indicates FT_CONFIG_OPTION_OLD_INTERNALS.
  87   if (major == 2 && minor == 4 && patch < 4 &&
  88       PR_FindFunctionSymbol(lib, "FT_Alloc")) {
  89     function = nullptr;
  90   }
  91
  92   // Decrement the reference count incremented in
  93   // PR_FindFunctionSymbolAndLibrary.
  94   PR_UnloadLibrary(lib);
  95
  96   return function;
  97 }
  98
  99 /*static*/
 100 void gfxFT2Utils::GetVariationAxes(const FT_MM_Var* aMMVar,
 101                                    nsTArray<gfxFontVariationAxis>& aAxes) {
 102   MOZ_ASSERT(aAxes.IsEmpty());
 103   if (!aMMVar) {
 104     return;
 105   }
 106   aAxes.SetCapacity(aMMVar->num_axis);
 107   for (unsigned i = 0; i < aMMVar->num_axis; i++) {
 108     const auto& a = aMMVar->axis[i];
 109     gfxFontVariationAxis axis;
 110     axis.mMinValue = a.minimum / 65536.0;
 111     axis.mMaxValue = a.maximum / 65536.0;
 112     axis.mDefaultValue = a.def / 65536.0;
 113     axis.mTag = a.tag;
 114     axis.mName = a.name;
 115     aAxes.AppendElement(axis);
 116   }
 117 }
 118
 119 /*static*/
 120 void gfxFT2Utils::GetVariationInstances(
 121     gfxFontEntry* aFontEntry, const FT_MM_Var* aMMVar,
 122     nsTArray<gfxFontVariationInstance>& aInstances) {
 123   MOZ_ASSERT(aInstances.IsEmpty());
 124   if (!aMMVar) {
 125     return;
 126   }
 127   hb_blob_t* nameTable =
 128       aFontEntry->GetFontTable(TRUETYPE_TAG('n', 'a', 'm', 'e'));
 129   if (!nameTable) {
 130     return;
 131   }
 132   aInstances.SetCapacity(aMMVar->num_namedstyles);
 133   for (unsigned i = 0; i < aMMVar->num_namedstyles; i++) {
 134     const auto& ns = aMMVar->namedstyle[i];
 135     gfxFontVariationInstance inst;
 136     nsresult rv =
 137         gfxFontUtils::ReadCanonicalName(nameTable, ns.strid, inst.mName);
 138     if (NS_FAILED(rv)) {
 139       continue;
 140     }
 141     inst.mValues.SetCapacity(aMMVar->num_axis);
 142     for (unsigned j = 0; j < aMMVar->num_axis; j++) {
 143       gfxFontVariationValue value;
 144       value.mAxis = aMMVar->axis[j].tag;
 145       value.mValue = ns.coords[j] / 65536.0;
 146       inst.mValues.AppendElement(value);
 147     }
 148     aInstances.AppendElement(inst);
 149   }
 150   hb_blob_destroy(nameTable);
 151 }