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 USE_FC_FREETYPE
  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 USE_FC_FREETYPE
  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   uint32_t gid = FcFreeTypeCharIndex(mFace, aCharCode);
  40 #else
  41   uint32_t gid = FT_Get_Char_Index(mFace, aCharCode);
  42 #endif
  43   if (!gid && mFace->charmap &&
  44       mFace->charmap->encoding == FT_ENCODING_MS_SYMBOL) {
  45     if (auto pua = gfxFontUtils::MapLegacySymbolFontCharToPUA(aCharCode)) {
  46       gid = FT_Get_Char_Index(mFace, pua);
  47     }
  48   }
  49   return gid;
  50 }
  51
  52 typedef FT_UInt (*GetCharVariantFunction)(FT_Face face, FT_ULong charcode,
  53                                           FT_ULong variantSelector);
  54
  55 uint32_t gfxFT2LockedFace::GetUVSGlyph(uint32_t aCharCode,
  56                                        uint32_t aVariantSelector) {
  57   MOZ_ASSERT(aVariantSelector, "aVariantSelector should not be NULL");
  58
  59   if (MOZ_UNLIKELY(!mFace)) return 0;
  60
  61   // This function is available from FreeType 2.3.6 (June 2008).
  62   static CharVariantFunction sGetCharVariantPtr = FindCharVariantFunction();
  63   if (!sGetCharVariantPtr) return 0;
  64
  65 #ifdef USE_FC_FREETYPE
  66   // FcFreeTypeCharIndex may have changed the selected charmap.
  67   // FT_Face_GetCharVariantIndex needs a unicode charmap.
  68   if (!mFace->charmap || mFace->charmap->encoding != FT_ENCODING_UNICODE) {
  69     FT_Select_Charmap(mFace, FT_ENCODING_UNICODE);
  70   }
  71 #endif
  72
  73   return (*sGetCharVariantPtr)(mFace, aCharCode, aVariantSelector);
  74 }
  75
  76 gfxFT2LockedFace::CharVariantFunction
  77 gfxFT2LockedFace::FindCharVariantFunction() {
  78   // This function is available from FreeType 2.3.6 (June 2008).
  79   PRLibrary* lib = nullptr;
  80   CharVariantFunction function = reinterpret_cast<CharVariantFunction>(
  81       PR_FindFunctionSymbolAndLibrary("FT_Face_GetCharVariantIndex", &lib));
  82   if (!lib) {
  83     return nullptr;
  84   }
  85
  86   FT_Int major;
  87   FT_Int minor;
  88   FT_Int patch;
  89   FT_Library_Version(mFace->glyph->library, &major, &minor, &patch);
  90
  91   // Versions 2.4.0 to 2.4.3 crash if configured with
  92   // FT_CONFIG_OPTION_OLD_INTERNALS.  Presence of the symbol FT_Alloc
  93   // indicates FT_CONFIG_OPTION_OLD_INTERNALS.
  94   if (major == 2 && minor == 4 && patch < 4 &&
  95       PR_FindFunctionSymbol(lib, "FT_Alloc")) {
  96     function = nullptr;
  97   }
  98
  99   // Decrement the reference count incremented in
 100   // PR_FindFunctionSymbolAndLibrary.
 101   PR_UnloadLibrary(lib);
 102
 103   return function;
 104 }
 105
 106 /*static*/
 107 void gfxFT2Utils::GetVariationAxes(const FT_MM_Var* aMMVar,
 108                                    nsTArray<gfxFontVariationAxis>& aAxes) {
 109   MOZ_ASSERT(aAxes.IsEmpty());
 110   if (!aMMVar) {
 111     return;
 112   }
 113   aAxes.SetCapacity(aMMVar->num_axis);
 114   for (unsigned i = 0; i < aMMVar->num_axis; i++) {
 115     const auto& a = aMMVar->axis[i];
 116     gfxFontVariationAxis axis;
 117     axis.mMinValue = a.minimum / 65536.0;
 118     axis.mMaxValue = a.maximum / 65536.0;
 119     axis.mDefaultValue = a.def / 65536.0;
 120     axis.mTag = a.tag;
 121     axis.mName = a.name;
 122     aAxes.AppendElement(axis);
 123   }
 124 }
 125
 126 /*static*/
 127 void gfxFT2Utils::GetVariationInstances(
 128     gfxFontEntry* aFontEntry, const FT_MM_Var* aMMVar,
 129     nsTArray<gfxFontVariationInstance>& aInstances) {
 130   MOZ_ASSERT(aInstances.IsEmpty());
 131   if (!aMMVar) {
 132     return;
 133   }
 134   gfxFontUtils::AutoHBBlob nameTable(
 135       aFontEntry->GetFontTable(TRUETYPE_TAG('n', 'a', 'm', 'e')));
 136   if (!nameTable) {
 137     return;
 138   }
 139   aInstances.SetCapacity(aMMVar->num_namedstyles);
 140   for (unsigned i = 0; i < aMMVar->num_namedstyles; i++) {
 141     const auto& ns = aMMVar->namedstyle[i];
 142     gfxFontVariationInstance inst;
 143     nsresult rv =
 144         gfxFontUtils::ReadCanonicalName(nameTable, ns.strid, inst.mName);
 145     if (NS_FAILED(rv)) {
 146       continue;
 147     }
 148     inst.mValues.SetCapacity(aMMVar->num_axis);
 149     for (unsigned j = 0; j < aMMVar->num_axis; j++) {
 150       gfxFontVariationValue value;
 151       value.mAxis = aMMVar->axis[j].tag;
 152       value.mValue = ns.coords[j] / 65536.0;
 153       inst.mValues.AppendElement(value);
 154     }
 155     aInstances.AppendElement(inst);
 156   }
 157 }