gecko-dev/gfx/thebes/gfxFT2Fonts.cpp

/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#if defined(MOZ_WIDGET_GTK)
#  include "gfxPlatformGtk.h"
#  define gfxToolkitPlatform gfxPlatformGtk
#elif defined(XP_WIN)
#  include "gfxWindowsPlatform.h"
#  define gfxToolkitPlatform gfxWindowsPlatform
#elif defined(ANDROID)
#  include "gfxAndroidPlatform.h"
#  define gfxToolkitPlatform gfxAndroidPlatform
#endif

#include "gfxTypes.h"
#include "gfxFT2Fonts.h"
#include "gfxFT2FontBase.h"
#include "gfxFT2Utils.h"
#include "gfxFT2FontList.h"
#include "gfxTextRun.h"
#include <locale.h>
#include "nsGkAtoms.h"
#include "nsTArray.h"
#include "nsCRT.h"
#include "nsXULAppAPI.h"

#include "mozilla/Logging.h"
#include "prinit.h"

#include "mozilla/MemoryReporting.h"
#include "mozilla/Preferences.h"
#include "mozilla/gfx/2D.h"

using namespace mozilla;
using namespace mozilla::gfx;

/**
 * gfxFT2Font
 */

bool gfxFT2Font::ShapeText(DrawTarget* aDrawTarget, const char16_t* aText,
                           uint32_t aOffset, uint32_t aLength, Script aScript,
                           nsAtom* aLanguage, bool aVertical,
                           RoundingFlags aRounding,
                           gfxShapedText* aShapedText) {
  if (!gfxFont::ShapeText(aDrawTarget, aText, aOffset, aLength, aScript,
                          aLanguage, aVertical, aRounding, aShapedText)) {
    // harfbuzz must have failed(?!), just render raw glyphs
    AddRange(aText, aOffset, aLength, aShapedText);
    PostShapingFixup(aDrawTarget, aText, aOffset, aLength, aVertical,
                     aShapedText);
  }

  return true;
}

void gfxFT2Font::AddRange(const char16_t* aText, uint32_t aOffset,
                          uint32_t aLength, gfxShapedText* aShapedText) {
  typedef gfxShapedText::CompressedGlyph CompressedGlyph;

  const uint32_t appUnitsPerDevUnit = aShapedText->GetAppUnitsPerDevUnit();
  // we'll pass this in/figure it out dynamically, but at this point there can
  // be only one face.
  gfxFT2LockedFace faceLock(this);
  FT_Face face = faceLock.get();

  CompressedGlyph* charGlyphs = aShapedText->GetCharacterGlyphs();

  const gfxFT2Font::CachedGlyphData *cgd = nullptr, *cgdNext = nullptr;

  FT_UInt spaceGlyph = GetSpaceGlyph();

  for (uint32_t i = 0; i < aLength; i++, aOffset++) {
    char16_t ch = aText[i];

    if (ch == 0) {
      // treat this null byte as a missing glyph, don't create a glyph for it
      aShapedText->SetMissingGlyph(aOffset, 0, this);
      continue;
    }

    NS_ASSERTION(!gfxFontGroup::IsInvalidChar(ch), "Invalid char detected");

    if (cgdNext) {
      cgd = cgdNext;
      cgdNext = nullptr;
    } else {
      cgd = GetGlyphDataForChar(face, ch);
    }

    FT_UInt gid = cgd->glyphIndex;
    int32_t advance = 0;

    if (gid == 0) {
      advance = -1;  // trigger the missing glyphs case below
    } else {
      // find next character and its glyph -- in case they exist
      // and exist in the current font face -- to compute kerning
      char16_t chNext = 0;
      FT_UInt gidNext = 0;
      FT_Pos lsbDeltaNext = 0;

      if (FT_HAS_KERNING(face) && i + 1 < aLength) {
        chNext = aText[i + 1];
        if (chNext != 0) {
          cgdNext = GetGlyphDataForChar(face, chNext);
          gidNext = cgdNext->glyphIndex;
          if (gidNext && gidNext != spaceGlyph)
            lsbDeltaNext = cgdNext->lsbDelta;
        }
      }

      advance = cgd->xAdvance;

      // now add kerning to the current glyph's advance
      if (chNext && gidNext) {
        FT_Vector kerning;
        kerning.x = 0;
        FT_Get_Kerning(face, gid, gidNext, FT_KERNING_DEFAULT, &kerning);
        advance += kerning.x;
        if (cgd->rsbDelta - lsbDeltaNext >= 32) {
          advance -= 64;
        } else if (cgd->rsbDelta - lsbDeltaNext < -32) {
          advance += 64;
        }
      }

      // convert 26.6 fixed point to app units
      // round rather than truncate to nearest pixel
      // because these advances are often scaled
      advance = ((advance * appUnitsPerDevUnit + 32) >> 6);
    }

    if (advance >= 0 && CompressedGlyph::IsSimpleAdvance(advance) &&
        CompressedGlyph::IsSimpleGlyphID(gid)) {
      charGlyphs[aOffset].SetSimpleGlyph(advance, gid);
    } else if (gid == 0) {
      // gid = 0 only happens when the glyph is missing from the font
      aShapedText->SetMissingGlyph(aOffset, ch, this);
    } else {
      gfxTextRun::DetailedGlyph details;
      details.mGlyphID = gid;
      NS_ASSERTION(details.mGlyphID == gid,
                   "Seriously weird glyph ID detected!");
      details.mAdvance = advance;
      aShapedText->SetDetailedGlyphs(aOffset, 1, &details);
    }
  }
}

gfxFT2Font::gfxFT2Font(const RefPtr<UnscaledFontFreeType>& aUnscaledFont,
                       RefPtr<mozilla::gfx::SharedFTFace>&& aFTFace,
                       FT2FontEntry* aFontEntry, const gfxFontStyle* aFontStyle,
                       int aLoadFlags)
    : gfxFT2FontBase(aUnscaledFont, std::move(aFTFace), aFontEntry, aFontStyle,
                     aLoadFlags, aFontStyle->NeedsSyntheticBold(aFontEntry)),
      mCharGlyphCache(32) {
  NS_ASSERTION(mFontEntry,
               "Unable to find font entry for font.  Something is whack.");
  InitMetrics();
}

gfxFT2Font::~gfxFT2Font() {}

already_AddRefed<ScaledFont> gfxFT2Font::GetScaledFont(DrawTarget* aTarget) {
  if (!mAzureScaledFont) {
    mAzureScaledFont = Factory::CreateScaledFontForFreeTypeFont(
        GetUnscaledFont(), GetAdjustedSize(), mFTFace,
        GetStyle()->NeedsSyntheticBold(GetFontEntry()));
    InitializeScaledFont();
  }

  RefPtr<ScaledFont> scaledFont(mAzureScaledFont);
  return scaledFont.forget();
}

bool gfxFT2Font::ShouldHintMetrics() const {
  return !gfxPlatform::GetPlatform()->RequiresLinearZoom();
}

void gfxFT2Font::FillGlyphDataForChar(FT_Face face, uint32_t ch,
                                      CachedGlyphData* gd) {
  if (!face->charmap || (face->charmap->encoding != FT_ENCODING_UNICODE &&
                         face->charmap->encoding != FT_ENCODING_MS_SYMBOL)) {
    if (FT_Err_Ok != FT_Select_Charmap(face, FT_ENCODING_UNICODE) &&
        FT_Err_Ok != FT_Select_Charmap(face, FT_ENCODING_MS_SYMBOL)) {
      NS_WARNING("failed to select Unicode or symbol charmap!");
    }
  }
  FT_UInt gid = FT_Get_Char_Index(face, ch);

  if (gid == 0) {
    // this font doesn't support this char!
    NS_ASSERTION(gid != 0,
                 "We don't have a glyph, but font indicated that it supported "
                 "this char in tables?");
    gd->glyphIndex = 0;
    return;
  }

  FT_Error err = Factory::LoadFTGlyph(face, gid, mFTLoadFlags);

  if (err) {
    // hmm, this is weird, we failed to load a glyph that we had?
    NS_WARNING("Failed to load glyph that we got from Get_Char_index");

    gd->glyphIndex = 0;
    return;
  }

  gd->glyphIndex = gid;
  gd->lsbDelta = face->glyph->lsb_delta;
  gd->rsbDelta = face->glyph->rsb_delta;
  gd->xAdvance = face->glyph->advance.x;
  if (gd->xAdvance) {
    gd->xAdvance += GetEmboldenStrength(face).x;
  }
}

void gfxFT2Font::AddSizeOfExcludingThis(MallocSizeOf aMallocSizeOf,
                                        FontCacheSizes* aSizes) const {
  gfxFont::AddSizeOfExcludingThis(aMallocSizeOf, aSizes);
  aSizes->mFontInstances +=
      mCharGlyphCache.ShallowSizeOfExcludingThis(aMallocSizeOf);
}

void gfxFT2Font::AddSizeOfIncludingThis(MallocSizeOf aMallocSizeOf,
                                        FontCacheSizes* aSizes) const {
  aSizes->mFontInstances += aMallocSizeOf(this);
  AddSizeOfExcludingThis(aMallocSizeOf, aSizes);
}