Adding upstream version 115.7.0esr.upstream/115.7.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 847 insertions, 0 deletions

diff --git a/gfx/thebes/gfxDWriteFonts.cpp b/gfx/thebes/gfxDWriteFonts.cpp
new file mode 100644
index 0000000000..fa6bc48cf9
--- /dev/null
+++ b/gfx/thebes/gfxDWriteFonts.cpp
@@ -0,0 +1,847 @@
+/* -*- 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/. */
+
+#include "gfxDWriteFonts.h"
+
+#include <algorithm>
+#include "gfxDWriteFontList.h"
+#include "gfxContext.h"
+#include "gfxHarfBuzzShaper.h"
+#include "gfxTextRun.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/DWriteSettings.h"
+#include "mozilla/gfx/Logging.h"
+#include "mozilla/gfx/gfxVars.h"
+#include "mozilla/Preferences.h"
+
+#include "harfbuzz/hb.h"
+#include "mozilla/FontPropertyTypes.h"
+
+using namespace mozilla;
+using namespace mozilla::gfx;
+
+// Code to determine whether Windows is set to use ClearType font smoothing;
+// based on private functions in cairo-win32-font.c
+
+#ifndef SPI_GETFONTSMOOTHINGTYPE
+#  define SPI_GETFONTSMOOTHINGTYPE 0x200a
+#endif
+#ifndef FE_FONTSMOOTHINGCLEARTYPE
+#  define FE_FONTSMOOTHINGCLEARTYPE 2
+#endif
+
+// Cleartype can be dynamically enabled/disabled, so we have to allow for
+// dynamically updating it.
+static BYTE GetSystemTextQuality() {
+  BOOL font_smoothing;
+  UINT smoothing_type;
+
+  if (!SystemParametersInfo(SPI_GETFONTSMOOTHING, 0, &font_smoothing, 0)) {
+    return DEFAULT_QUALITY;
+  }
+
+  if (font_smoothing) {
+    if (!SystemParametersInfo(SPI_GETFONTSMOOTHINGTYPE, 0, &smoothing_type,
+                              0)) {
+      return DEFAULT_QUALITY;
+    }
+
+    if (smoothing_type == FE_FONTSMOOTHINGCLEARTYPE) {
+      return CLEARTYPE_QUALITY;
+    }
+
+    return ANTIALIASED_QUALITY;
+  }
+
+  return DEFAULT_QUALITY;
+}
+
+#ifndef SPI_GETFONTSMOOTHINGCONTRAST
+#  define SPI_GETFONTSMOOTHINGCONTRAST 0x200c
+#endif
+
+// "Retrieves a contrast value that is used in ClearType smoothing. Valid
+// contrast values are from 1000 to 2200. The default value is 1400."
+static FLOAT GetSystemGDIGamma() {
+  UINT value = 0;
+  if (!SystemParametersInfo(SPI_GETFONTSMOOTHINGCONTRAST, 0, &value, 0) ||
+      value < 1000 || value > 2200) {
+    value = 1400;
+  }
+  return value / 1000.0f;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// gfxDWriteFont
+gfxDWriteFont::gfxDWriteFont(const RefPtr<UnscaledFontDWrite>& aUnscaledFont,
+                             gfxFontEntry* aFontEntry,
+                             const gfxFontStyle* aFontStyle,
+                             RefPtr<IDWriteFontFace> aFontFace,
+                             AntialiasOption anAAOption)
+    : gfxFont(aUnscaledFont, aFontEntry, aFontStyle, anAAOption),
+      mFontFace(aFontFace ? aFontFace : aUnscaledFont->GetFontFace()),
+      mUseSubpixelPositions(false),
+      mAllowManualShowGlyphs(true),
+      mAzureScaledFontUsedClearType(false) {
+  // If the IDWriteFontFace1 interface is available, we can use that for
+  // faster glyph width retrieval.
+  mFontFace->QueryInterface(__uuidof(IDWriteFontFace1),
+                            (void**)getter_AddRefs(mFontFace1));
+  // If a fake-bold effect is needed, determine whether we're using DWrite's
+  // "simulation" or applying our multi-strike "synthetic bold".
+  if (aFontStyle->NeedsSyntheticBold(aFontEntry)) {
+    switch (StaticPrefs::gfx_font_rendering_directwrite_bold_simulation()) {
+      case 0:  // never use the DWrite simulation
+        mApplySyntheticBold = true;
+        break;
+      case 1:  // use DWrite simulation for installed fonts but not webfonts
+        mApplySyntheticBold = aFontEntry->mIsDataUserFont;
+        break;
+      default:  // always use DWrite bold simulation
+        // the flag is initialized to false in gfxFont
+        break;
+    }
+  }
+  ComputeMetrics(anAAOption);
+}
+
+gfxDWriteFont::~gfxDWriteFont() {
+  if (auto* scaledFont = mAzureScaledFontGDI.exchange(nullptr)) {
+    scaledFont->Release();
+  }
+}
+
+/* static */
+bool gfxDWriteFont::InitDWriteSupport() {
+  if (!Factory::EnsureDWriteFactory()) {
+    return false;
+  }
+
+  if (XRE_IsParentProcess()) {
+    UpdateSystemTextVars();
+  } else {
+    // UpdateClearTypeVars doesn't update the vars in non parent processes, but
+    // it does set sForceGDIClassicEnabled so we still need to call it.
+    UpdateClearTypeVars();
+  }
+  DWriteSettings::Initialize();
+
+  return true;
+}
+
+/* static */
+void gfxDWriteFont::UpdateSystemTextVars() {
+  MOZ_ASSERT(XRE_IsParentProcess());
+
+  if (!gfxVars::IsInitialized()) {
+    return;
+  }
+
+  BYTE newQuality = GetSystemTextQuality();
+  if (gfxVars::SystemTextQuality() != newQuality) {
+    gfxVars::SetSystemTextQuality(newQuality);
+  }
+
+  FLOAT newGDIGamma = GetSystemGDIGamma();
+  if (gfxVars::SystemGDIGamma() != newGDIGamma) {
+    gfxVars::SetSystemGDIGamma(newGDIGamma);
+  }
+
+  UpdateClearTypeVars();
+}
+
+void gfxDWriteFont::SystemTextQualityChanged() {
+  // If ClearType status has changed, update our value,
+  Factory::SetSystemTextQuality(gfxVars::SystemTextQuality());
+  // flush cached stuff that depended on the old setting, and force
+  // reflow everywhere to ensure we are using correct glyph metrics.
+  gfxPlatform::FlushFontAndWordCaches();
+  gfxPlatform::ForceGlobalReflow(gfxPlatform::NeedsReframe::No);
+}
+
+mozilla::Atomic<bool> gfxDWriteFont::sForceGDIClassicEnabled{true};
+
+/* static */
+void gfxDWriteFont::UpdateClearTypeVars() {
+  // We don't force GDI classic if the cleartype rendering mode pref is set to
+  // something valid.
+  int32_t renderingModePref =
+      Preferences::GetInt(GFX_CLEARTYPE_PARAMS_MODE, -1);
+  if (renderingModePref < 0 || renderingModePref > 5) {
+    renderingModePref = -1;
+  }
+  sForceGDIClassicEnabled = (renderingModePref == -1);
+
+  if (!XRE_IsParentProcess()) {
+    return;
+  }
+
+  if (!Factory::GetDWriteFactory()) {
+    return;
+  }
+
+  // First set sensible hard coded defaults.
+  float clearTypeLevel = 1.0f;
+  float enhancedContrast = 1.0f;
+  float gamma = 2.2f;
+  int pixelGeometry = DWRITE_PIXEL_GEOMETRY_RGB;
+  int renderingMode = DWRITE_RENDERING_MODE_DEFAULT;
+
+  // Override these from DWrite function if available.
+  RefPtr<IDWriteRenderingParams> defaultRenderingParams;
+  HRESULT hr = Factory::GetDWriteFactory()->CreateRenderingParams(
+      getter_AddRefs(defaultRenderingParams));
+  if (SUCCEEDED(hr) && defaultRenderingParams) {
+    clearTypeLevel = defaultRenderingParams->GetClearTypeLevel();
+
+    // For enhanced contrast, we only use the default if the user has set it
+    // in the registry (by using the ClearType Tuner).
+    // XXXbobowen it seems slightly odd that we do this and only for enhanced
+    // contrast, but this reproduces previous functionality from
+    // gfxWindowsPlatform::SetupClearTypeParams.
+    HKEY hKey;
+    LONG res = RegOpenKeyExW(DISPLAY1_REGISTRY_KEY, 0, KEY_READ, &hKey);
+    if (res == ERROR_SUCCESS) {
+      res = RegQueryValueExW(hKey, ENHANCED_CONTRAST_VALUE_NAME, nullptr,
+                             nullptr, nullptr, nullptr);
+      if (res == ERROR_SUCCESS) {
+        enhancedContrast = defaultRenderingParams->GetEnhancedContrast();
+      }
+      RegCloseKey(hKey);
+    }
+
+    gamma = defaultRenderingParams->GetGamma();
+    pixelGeometry = defaultRenderingParams->GetPixelGeometry();
+    renderingMode = defaultRenderingParams->GetRenderingMode();
+  } else {
+    gfxWarning() << "Failed to create default rendering params";
+  }
+
+  // Finally override from prefs if valid values are set. If ClearType is
+  // turned off we just use the default params, this reproduces the previous
+  // functionality that was spread across gfxDWriteFont::GetScaledFont and
+  // gfxWindowsPlatform::SetupClearTypeParams, but it seems odd because the
+  // default params will still be the ClearType ones although we won't use the
+  // anti-alias for ClearType because of GetSystemDefaultAAMode.
+  if (gfxVars::SystemTextQuality() == CLEARTYPE_QUALITY) {
+    int32_t prefInt = Preferences::GetInt(GFX_CLEARTYPE_PARAMS_LEVEL, -1);
+    if (prefInt >= 0 && prefInt <= 100) {
+      clearTypeLevel = float(prefInt / 100.0);
+    }
+
+    prefInt = Preferences::GetInt(GFX_CLEARTYPE_PARAMS_CONTRAST, -1);
+    if (prefInt >= 0 && prefInt <= 1000) {
+      enhancedContrast = float(prefInt / 100.0);
+    }
+
+    prefInt = Preferences::GetInt(GFX_CLEARTYPE_PARAMS_GAMMA, -1);
+    if (prefInt >= 1000 && prefInt <= 2200) {
+      gamma = float(prefInt / 1000.0);
+    }
+
+    prefInt = Preferences::GetInt(GFX_CLEARTYPE_PARAMS_STRUCTURE, -1);
+    if (prefInt >= 0 && prefInt <= 2) {
+      pixelGeometry = prefInt;
+    }
+
+    // renderingModePref is retrieved and validated above.
+    if (renderingModePref != -1) {
+      renderingMode = renderingModePref;
+    }
+  }
+
+  if (gfxVars::SystemTextClearTypeLevel() != clearTypeLevel) {
+    gfxVars::SetSystemTextClearTypeLevel(clearTypeLevel);
+  }
+
+  if (gfxVars::SystemTextEnhancedContrast() != enhancedContrast) {
+    gfxVars::SetSystemTextEnhancedContrast(enhancedContrast);
+  }
+
+  if (gfxVars::SystemTextGamma() != gamma) {
+    gfxVars::SetSystemTextGamma(gamma);
+  }
+
+  if (gfxVars::SystemTextPixelGeometry() != pixelGeometry) {
+    gfxVars::SetSystemTextPixelGeometry(pixelGeometry);
+  }
+
+  if (gfxVars::SystemTextRenderingMode() != renderingMode) {
+    gfxVars::SetSystemTextRenderingMode(renderingMode);
+  }
+
+  // Set cairo dwrite params in the parent process where it might still be
+  // needed for printing. We use the validated pref int directly for rendering
+  // mode, because a negative (i.e. not set) rendering mode is also used for
+  // deciding on forcing GDI in cairo.
+  cairo_dwrite_set_cleartype_params(gamma, enhancedContrast, clearTypeLevel,
+                                    pixelGeometry, renderingModePref);
+}
+
+gfxFont* gfxDWriteFont::CopyWithAntialiasOption(
+    AntialiasOption anAAOption) const {
+  auto entry = static_cast<gfxDWriteFontEntry*>(mFontEntry.get());
+  RefPtr<UnscaledFontDWrite> unscaledFont =
+      static_cast<UnscaledFontDWrite*>(mUnscaledFont.get());
+  return new gfxDWriteFont(unscaledFont, entry, &mStyle, mFontFace, anAAOption);
+}
+
+bool gfxDWriteFont::GetFakeMetricsForArialBlack(
+    DWRITE_FONT_METRICS* aFontMetrics) {
+  gfxFontStyle style(mStyle);
+  style.weight = FontWeight::FromInt(700);
+
+  gfxFontEntry* fe = gfxPlatformFontList::PlatformFontList()->FindFontForFamily(
+      nullptr, "Arial"_ns, &style);
+  if (!fe || fe == mFontEntry) {
+    return false;
+  }
+
+  RefPtr<gfxFont> font = fe->FindOrMakeFont(&style);
+  gfxDWriteFont* dwFont = static_cast<gfxDWriteFont*>(font.get());
+  dwFont->mFontFace->GetMetrics(aFontMetrics);
+
+  return true;
+}
+
+void gfxDWriteFont::ComputeMetrics(AntialiasOption anAAOption) {
+  ::memset(&mMetrics, 0, sizeof(mMetrics));
+
+  DWRITE_FONT_METRICS fontMetrics;
+  if (!(mFontEntry->Weight().Min() == FontWeight::FromInt(900) &&
+        mFontEntry->Weight().Max() == FontWeight::FromInt(900) &&
+        !mFontEntry->IsUserFont() &&
+        mFontEntry->Name().EqualsLiteral("Arial Black") &&
+        GetFakeMetricsForArialBlack(&fontMetrics))) {
+    mFontFace->GetMetrics(&fontMetrics);
+  }
+
+  if (GetAdjustedSize() > 0.0 && mStyle.sizeAdjust >= 0.0 &&
+      FontSizeAdjust::Tag(mStyle.sizeAdjustBasis) !=
+          FontSizeAdjust::Tag::None) {
+    // For accurate measurement during the font-size-adjust computations;
+    // these may be reset later according to the adjusted size.
+    mUseSubpixelPositions = true;
+    mFUnitsConvFactor = float(mAdjustedSize / fontMetrics.designUnitsPerEm);
+    gfxFloat aspect;
+    switch (FontSizeAdjust::Tag(mStyle.sizeAdjustBasis)) {
+      default:
+        MOZ_ASSERT_UNREACHABLE("unhandled sizeAdjustBasis?");
+        aspect = 0.0;
+        break;
+      case FontSizeAdjust::Tag::ExHeight:
+        aspect = (gfxFloat)fontMetrics.xHeight / fontMetrics.designUnitsPerEm;
+        break;
+      case FontSizeAdjust::Tag::CapHeight:
+        aspect = (gfxFloat)fontMetrics.capHeight / fontMetrics.designUnitsPerEm;
+        break;
+      case FontSizeAdjust::Tag::ChWidth: {
+        gfxFloat advance = GetCharAdvance('0');
+        aspect = advance > 0.0 ? advance / mAdjustedSize : 0.5;
+        break;
+      }
+      case FontSizeAdjust::Tag::IcWidth:
+      case FontSizeAdjust::Tag::IcHeight: {
+        bool vertical = FontSizeAdjust::Tag(mStyle.sizeAdjustBasis) ==
+                        FontSizeAdjust::Tag::IcHeight;
+        gfxFloat advance = GetCharAdvance(kWaterIdeograph, vertical);
+        aspect = advance > 0.0 ? advance / mAdjustedSize : 1.0;
+        break;
+      }
+    }
+    if (aspect > 0.0) {
+      // If we created a shaper above (to measure glyphs), discard it so we
+      // get a new one for the adjusted scaling.
+      delete mHarfBuzzShaper.exchange(nullptr);
+      mAdjustedSize = mStyle.GetAdjustedSize(aspect);
+    }
+  }
+
+  // Update now that we've adjusted the size if necessary.
+  mFUnitsConvFactor = float(mAdjustedSize / fontMetrics.designUnitsPerEm);
+
+  // Note that GetMeasuringMode depends on mAdjustedSize
+  if ((anAAOption == gfxFont::kAntialiasDefault && UsingClearType() &&
+       GetMeasuringMode() == DWRITE_MEASURING_MODE_NATURAL) ||
+      anAAOption == gfxFont::kAntialiasSubpixel) {
+    mUseSubpixelPositions = true;
+    // note that this may be reset to FALSE if we determine that a bitmap
+    // strike is going to be used
+  } else {
+    mUseSubpixelPositions = false;
+  }
+
+  gfxDWriteFontEntry* fe = static_cast<gfxDWriteFontEntry*>(mFontEntry.get());
+  if (fe->IsCJKFont() && HasBitmapStrikeForSize(NS_lround(mAdjustedSize))) {
+    mAdjustedSize = NS_lround(mAdjustedSize);
+    mUseSubpixelPositions = false;
+    // if we have bitmaps, we need to tell Cairo NOT to use subpixel AA,
+    // to avoid the manual-subpixel codepath in cairo-d2d-surface.cpp
+    // which fails to render bitmap glyphs (see bug 626299).
+    // This option will be passed to the cairo_dwrite_scaled_font_t
+    // after creation.
+    mAllowManualShowGlyphs = false;
+  }
+
+  mMetrics.xHeight = fontMetrics.xHeight * mFUnitsConvFactor;
+  mMetrics.capHeight = fontMetrics.capHeight * mFUnitsConvFactor;
+
+  mMetrics.maxAscent = round(fontMetrics.ascent * mFUnitsConvFactor);
+  mMetrics.maxDescent = round(fontMetrics.descent * mFUnitsConvFactor);
+  mMetrics.maxHeight = mMetrics.maxAscent + mMetrics.maxDescent;
+
+  mMetrics.emHeight = mAdjustedSize;
+  mMetrics.emAscent =
+      mMetrics.emHeight * mMetrics.maxAscent / mMetrics.maxHeight;
+  mMetrics.emDescent = mMetrics.emHeight - mMetrics.emAscent;
+
+  mMetrics.maxAdvance = mAdjustedSize;
+
+  // try to get the true maxAdvance value from 'hhea'
+  gfxFontEntry::AutoTable hheaTable(GetFontEntry(),
+                                    TRUETYPE_TAG('h', 'h', 'e', 'a'));
+  if (hheaTable) {
+    uint32_t len;
+    const MetricsHeader* hhea = reinterpret_cast<const MetricsHeader*>(
+        hb_blob_get_data(hheaTable, &len));
+    if (len >= sizeof(MetricsHeader)) {
+      mMetrics.maxAdvance = uint16_t(hhea->advanceWidthMax) * mFUnitsConvFactor;
+    }
+  }
+
+  mMetrics.internalLeading =
+      std::max(mMetrics.maxHeight - mMetrics.emHeight, 0.0);
+  mMetrics.externalLeading = ceil(fontMetrics.lineGap * mFUnitsConvFactor);
+
+  UINT32 ucs = L' ';
+  UINT16 glyph;
+  if (SUCCEEDED(mFontFace->GetGlyphIndices(&ucs, 1, &glyph)) && glyph != 0) {
+    mSpaceGlyph = glyph;
+    mMetrics.spaceWidth = MeasureGlyphWidth(glyph);
+  } else {
+    mMetrics.spaceWidth = 0;
+  }
+
+  // try to get aveCharWidth from the OS/2 table, fall back to measuring 'x'
+  // if the table is not available or if using hinted/pixel-snapped widths
+  if (mUseSubpixelPositions) {
+    mMetrics.aveCharWidth = 0;
+    gfxFontEntry::AutoTable os2Table(GetFontEntry(),
+                                     TRUETYPE_TAG('O', 'S', '/', '2'));
+    if (os2Table) {
+      uint32_t len;
+      const OS2Table* os2 =
+          reinterpret_cast<const OS2Table*>(hb_blob_get_data(os2Table, &len));
+      if (len >= 4) {
+        // Not checking against sizeof(mozilla::OS2Table) here because older
+        // versions of the table have different sizes; we only need the first
+        // two 16-bit fields here.
+        mMetrics.aveCharWidth = int16_t(os2->xAvgCharWidth) * mFUnitsConvFactor;
+      }
+    }
+  }
+
+  if (mMetrics.aveCharWidth < 1) {
+    mMetrics.aveCharWidth = GetCharAdvance('x');
+    if (mMetrics.aveCharWidth < 1) {
+      // Let's just assume the X is square.
+      mMetrics.aveCharWidth = fontMetrics.xHeight * mFUnitsConvFactor;
+    }
+  }
+
+  mMetrics.zeroWidth = GetCharAdvance('0');
+
+  mMetrics.ideographicWidth = GetCharAdvance(kWaterIdeograph);
+
+  mMetrics.underlineOffset = fontMetrics.underlinePosition * mFUnitsConvFactor;
+  mMetrics.underlineSize = fontMetrics.underlineThickness * mFUnitsConvFactor;
+  mMetrics.strikeoutOffset =
+      fontMetrics.strikethroughPosition * mFUnitsConvFactor;
+  mMetrics.strikeoutSize =
+      fontMetrics.strikethroughThickness * mFUnitsConvFactor;
+
+  SanitizeMetrics(&mMetrics, GetFontEntry()->mIsBadUnderlineFont);
+
+  if (ApplySyntheticBold()) {
+    auto delta = GetSyntheticBoldOffset();
+    mMetrics.spaceWidth += delta;
+    mMetrics.aveCharWidth += delta;
+    mMetrics.maxAdvance += delta;
+    if (mMetrics.zeroWidth > 0) {
+      mMetrics.zeroWidth += delta;
+    }
+    if (mMetrics.ideographicWidth > 0) {
+      mMetrics.ideographicWidth += delta;
+    }
+  }
+
+#if 0
+    printf("Font: %p (%s) size: %f\n", this,
+           NS_ConvertUTF16toUTF8(GetName()).get(), mStyle.size);
+    printf("    emHeight: %f emAscent: %f emDescent: %f\n", mMetrics.emHeight, mMetrics.emAscent, mMetrics.emDescent);
+    printf("    maxAscent: %f maxDescent: %f maxAdvance: %f\n", mMetrics.maxAscent, mMetrics.maxDescent, mMetrics.maxAdvance);
+    printf("    internalLeading: %f externalLeading: %f\n", mMetrics.internalLeading, mMetrics.externalLeading);
+    printf("    spaceWidth: %f aveCharWidth: %f zeroWidth: %f\n",
+           mMetrics.spaceWidth, mMetrics.aveCharWidth, mMetrics.zeroWidth);
+    printf("    xHeight: %f capHeight: %f\n", mMetrics.xHeight, mMetrics.capHeight);
+    printf("    uOff: %f uSize: %f stOff: %f stSize: %f\n",
+           mMetrics.underlineOffset, mMetrics.underlineSize, mMetrics.strikeoutOffset, mMetrics.strikeoutSize);
+#endif
+}
+
+using namespace mozilla;  // for AutoSwap_* types
+
+struct EBLCHeader {
+  AutoSwap_PRUint32 version;
+  AutoSwap_PRUint32 numSizes;
+};
+
+struct SbitLineMetrics {
+  int8_t ascender;
+  int8_t descender;
+  uint8_t widthMax;
+  int8_t caretSlopeNumerator;
+  int8_t caretSlopeDenominator;
+  int8_t caretOffset;
+  int8_t minOriginSB;
+  int8_t minAdvanceSB;
+  int8_t maxBeforeBL;
+  int8_t minAfterBL;
+  int8_t pad1;
+  int8_t pad2;
+};
+
+struct BitmapSizeTable {
+  AutoSwap_PRUint32 indexSubTableArrayOffset;
+  AutoSwap_PRUint32 indexTablesSize;
+  AutoSwap_PRUint32 numberOfIndexSubTables;
+  AutoSwap_PRUint32 colorRef;
+  SbitLineMetrics hori;
+  SbitLineMetrics vert;
+  AutoSwap_PRUint16 startGlyphIndex;
+  AutoSwap_PRUint16 endGlyphIndex;
+  uint8_t ppemX;
+  uint8_t ppemY;
+  uint8_t bitDepth;
+  uint8_t flags;
+};
+
+typedef EBLCHeader EBSCHeader;
+
+struct BitmapScaleTable {
+  SbitLineMetrics hori;
+  SbitLineMetrics vert;
+  uint8_t ppemX;
+  uint8_t ppemY;
+  uint8_t substitutePpemX;
+  uint8_t substitutePpemY;
+};
+
+bool gfxDWriteFont::HasBitmapStrikeForSize(uint32_t aSize) {
+  uint8_t* tableData;
+  uint32_t len;
+  void* tableContext;
+  BOOL exists;
+  HRESULT hr = mFontFace->TryGetFontTable(
+      DWRITE_MAKE_OPENTYPE_TAG('E', 'B', 'L', 'C'), (const void**)&tableData,
+      &len, &tableContext, &exists);
+  if (FAILED(hr)) {
+    return false;
+  }
+
+  bool hasStrike = false;
+  // not really a loop, but this lets us use 'break' to skip out of the block
+  // as soon as we know the answer, and skips it altogether if the table is
+  // not present
+  while (exists) {
+    if (len < sizeof(EBLCHeader)) {
+      break;
+    }
+    const EBLCHeader* hdr = reinterpret_cast<const EBLCHeader*>(tableData);
+    if (hdr->version != 0x00020000) {
+      break;
+    }
+    uint32_t numSizes = hdr->numSizes;
+    if (numSizes > 0xffff) {  // sanity-check, prevent overflow below
+      break;
+    }
+    if (len < sizeof(EBLCHeader) + numSizes * sizeof(BitmapSizeTable)) {
+      break;
+    }
+    const BitmapSizeTable* sizeTable =
+        reinterpret_cast<const BitmapSizeTable*>(hdr + 1);
+    for (uint32_t i = 0; i < numSizes; ++i, ++sizeTable) {
+      if (sizeTable->ppemX == aSize && sizeTable->ppemY == aSize) {
+        // we ignore a strike that contains fewer than 4 glyphs,
+        // as that probably indicates a font such as Courier New
+        // that provides bitmaps ONLY for the "shading" characters
+        // U+2591..2593
+        hasStrike = (uint16_t(sizeTable->endGlyphIndex) >=
+                     uint16_t(sizeTable->startGlyphIndex) + 3);
+        break;
+      }
+    }
+    // if we reach here, we didn't find a strike; unconditionally break
+    // out of the while-loop block
+    break;
+  }
+  mFontFace->ReleaseFontTable(tableContext);
+
+  if (hasStrike) {
+    return true;
+  }
+
+  // if we didn't find a real strike, check if the font calls for scaling
+  // another bitmap to this size
+  hr = mFontFace->TryGetFontTable(DWRITE_MAKE_OPENTYPE_TAG('E', 'B', 'S', 'C'),
+                                  (const void**)&tableData, &len, &tableContext,
+                                  &exists);
+  if (FAILED(hr)) {
+    return false;
+  }
+
+  while (exists) {
+    if (len < sizeof(EBSCHeader)) {
+      break;
+    }
+    const EBSCHeader* hdr = reinterpret_cast<const EBSCHeader*>(tableData);
+    if (hdr->version != 0x00020000) {
+      break;
+    }
+    uint32_t numSizes = hdr->numSizes;
+    if (numSizes > 0xffff) {
+      break;
+    }
+    if (len < sizeof(EBSCHeader) + numSizes * sizeof(BitmapScaleTable)) {
+      break;
+    }
+    const BitmapScaleTable* scaleTable =
+        reinterpret_cast<const BitmapScaleTable*>(hdr + 1);
+    for (uint32_t i = 0; i < numSizes; ++i, ++scaleTable) {
+      if (scaleTable->ppemX == aSize && scaleTable->ppemY == aSize) {
+        hasStrike = true;
+        break;
+      }
+    }
+    break;
+  }
+  mFontFace->ReleaseFontTable(tableContext);
+
+  return hasStrike;
+}
+
+bool gfxDWriteFont::IsValid() const { return mFontFace != nullptr; }
+
+IDWriteFontFace* gfxDWriteFont::GetFontFace() { return mFontFace.get(); }
+
+gfxFont::RunMetrics gfxDWriteFont::Measure(const gfxTextRun* aTextRun,
+                                           uint32_t aStart, uint32_t aEnd,
+                                           BoundingBoxType aBoundingBoxType,
+                                           DrawTarget* aRefDrawTarget,
+                                           Spacing* aSpacing,
+                                           gfx::ShapedTextFlags aOrientation) {
+  gfxFont::RunMetrics metrics =
+      gfxFont::Measure(aTextRun, aStart, aEnd, aBoundingBoxType, aRefDrawTarget,
+                       aSpacing, aOrientation);
+
+  // if aBoundingBoxType is LOOSE_INK_EXTENTS
+  // and the underlying cairo font may be antialiased,
+  // we can't trust Windows to have considered all the pixels
+  // so we need to add "padding" to the bounds.
+  // (see bugs 475968, 439831, compare also bug 445087)
+  if (aBoundingBoxType == LOOSE_INK_EXTENTS &&
+      mAntialiasOption != kAntialiasNone &&
+      GetMeasuringMode() == DWRITE_MEASURING_MODE_GDI_CLASSIC &&
+      metrics.mBoundingBox.Width() > 0) {
+    metrics.mBoundingBox.MoveByX(-aTextRun->GetAppUnitsPerDevUnit());
+    metrics.mBoundingBox.SetWidth(metrics.mBoundingBox.Width() +
+                                  aTextRun->GetAppUnitsPerDevUnit() * 3);
+  }
+
+  return metrics;
+}
+
+bool gfxDWriteFont::ProvidesGlyphWidths() const {
+  return !mUseSubpixelPositions ||
+         (mFontFace->GetSimulations() & DWRITE_FONT_SIMULATIONS_BOLD) ||
+         ((gfxDWriteFontEntry*)(GetFontEntry()))->HasVariations();
+}
+
+int32_t gfxDWriteFont::GetGlyphWidth(uint16_t aGID) {
+  if (!mGlyphWidths) {
+    mGlyphWidths = MakeUnique<nsTHashMap<nsUint32HashKey, int32_t>>(128);
+  }
+
+  return mGlyphWidths->LookupOrInsertWith(
+      aGID, [&] { return NS_lround(MeasureGlyphWidth(aGID) * 65536.0); });
+}
+
+bool gfxDWriteFont::GetForceGDIClassic() const {
+  return sForceGDIClassicEnabled &&
+         static_cast<gfxDWriteFontEntry*>(mFontEntry.get())
+             ->GetForceGDIClassic() &&
+         GetAdjustedSize() <= gfxDWriteFontList::PlatformFontList()
+                                  ->GetForceGDIClassicMaxFontSize();
+}
+
+DWRITE_MEASURING_MODE
+gfxDWriteFont::GetMeasuringMode() const {
+  return DWriteSettings::Get(GetForceGDIClassic()).MeasuringMode();
+}
+
+gfxFloat gfxDWriteFont::MeasureGlyphWidth(uint16_t aGlyph) {
+  MOZ_SEH_TRY {
+    HRESULT hr;
+    if (mFontFace1) {
+      int32_t advance;
+      if (mUseSubpixelPositions) {
+        hr = mFontFace1->GetDesignGlyphAdvances(1, &aGlyph, &advance, FALSE);
+        if (SUCCEEDED(hr)) {
+          return advance * mFUnitsConvFactor;
+        }
+      } else {
+        hr = mFontFace1->GetGdiCompatibleGlyphAdvances(
+            FLOAT(mAdjustedSize), 1.0f, nullptr,
+            GetMeasuringMode() == DWRITE_MEASURING_MODE_GDI_NATURAL, FALSE, 1,
+            &aGlyph, &advance);
+        if (SUCCEEDED(hr)) {
+          return NS_lround(advance * mFUnitsConvFactor);
+        }
+      }
+    } else {
+      DWRITE_GLYPH_METRICS metrics;
+      if (mUseSubpixelPositions) {
+        hr = mFontFace->GetDesignGlyphMetrics(&aGlyph, 1, &metrics, FALSE);
+        if (SUCCEEDED(hr)) {
+          return metrics.advanceWidth * mFUnitsConvFactor;
+        }
+      } else {
+        hr = mFontFace->GetGdiCompatibleGlyphMetrics(
+            FLOAT(mAdjustedSize), 1.0f, nullptr,
+            GetMeasuringMode() == DWRITE_MEASURING_MODE_GDI_NATURAL, &aGlyph, 1,
+            &metrics, FALSE);
+        if (SUCCEEDED(hr)) {
+          return NS_lround(metrics.advanceWidth * mFUnitsConvFactor);
+        }
+      }
+    }
+  }
+  MOZ_SEH_EXCEPT(EXCEPTION_EXECUTE_HANDLER) {
+    // Exception (e.g. disk i/o error) occurred when DirectWrite tried to use
+    // the font resource; possibly a failing drive or similar hardware issue.
+    // Mark the font as invalid, and wipe the fontEntry's charmap so that font
+    // selection will skip it; we'll use a fallback font instead.
+    mIsValid = false;
+    GetFontEntry()->mCharacterMap = new gfxCharacterMap();
+    GetFontEntry()->mShmemCharacterMap = nullptr;
+    gfxCriticalError() << "Exception occurred measuring glyph width for "
+                       << GetFontEntry()->Name().get();
+  }
+  return 0.0;
+}
+
+bool gfxDWriteFont::GetGlyphBounds(uint16_t aGID, gfxRect* aBounds,
+                                   bool aTight) {
+  MOZ_SEH_TRY {
+    DWRITE_GLYPH_METRICS m;
+    HRESULT hr = mFontFace->GetDesignGlyphMetrics(&aGID, 1, &m, FALSE);
+    if (FAILED(hr)) {
+      return false;
+    }
+    gfxRect bounds(m.leftSideBearing, m.topSideBearing - m.verticalOriginY,
+                   m.advanceWidth - m.leftSideBearing - m.rightSideBearing,
+                   m.advanceHeight - m.topSideBearing - m.bottomSideBearing);
+    bounds.Scale(mFUnitsConvFactor);
+    // GetDesignGlyphMetrics returns 'ideal' glyph metrics, we need to pad to
+    // account for antialiasing.
+    if (!aTight && !aBounds->IsEmpty()) {
+      bounds.Inflate(1.0, 0.0);
+    }
+    *aBounds = bounds;
+    return true;
+  }
+  MOZ_SEH_EXCEPT(EXCEPTION_EXECUTE_HANDLER) {
+    // Exception (e.g. disk i/o error) occurred when DirectWrite tried to use
+    // the font resource; possibly a failing drive or similar hardware issue.
+    // Mark the font as invalid, and wipe the fontEntry's charmap so that font
+    // selection will skip it; we'll use a fallback font instead.
+    mIsValid = false;
+    GetFontEntry()->mCharacterMap = new gfxCharacterMap();
+    GetFontEntry()->mShmemCharacterMap = nullptr;
+    gfxCriticalError() << "Exception occurred measuring glyph bounds for "
+                       << GetFontEntry()->Name().get();
+  }
+  return false;
+}
+
+void gfxDWriteFont::AddSizeOfExcludingThis(MallocSizeOf aMallocSizeOf,
+                                           FontCacheSizes* aSizes) const {
+  gfxFont::AddSizeOfExcludingThis(aMallocSizeOf, aSizes);
+  if (mGlyphWidths) {
+    aSizes->mFontInstances +=
+        mGlyphWidths->ShallowSizeOfIncludingThis(aMallocSizeOf);
+  }
+}
+
+void gfxDWriteFont::AddSizeOfIncludingThis(MallocSizeOf aMallocSizeOf,
+                                           FontCacheSizes* aSizes) const {
+  aSizes->mFontInstances += aMallocSizeOf(this);
+  AddSizeOfExcludingThis(aMallocSizeOf, aSizes);
+}
+
+already_AddRefed<ScaledFont> gfxDWriteFont::GetScaledFont(
+    const TextRunDrawParams& aRunParams) {
+  bool useClearType = UsingClearType();
+  if (mAzureScaledFontUsedClearType != useClearType) {
+    if (auto* oldScaledFont = mAzureScaledFont.exchange(nullptr)) {
+      oldScaledFont->Release();
+    }
+    if (auto* oldScaledFont = mAzureScaledFontGDI.exchange(nullptr)) {
+      oldScaledFont->Release();
+    }
+  }
+  bool forceGDI = aRunParams.allowGDI && GetForceGDIClassic();
+  ScaledFont* scaledFont = forceGDI ? mAzureScaledFontGDI : mAzureScaledFont;
+  if (scaledFont) {
+    return do_AddRef(scaledFont);
+  }
+
+  gfxDWriteFontEntry* fe = static_cast<gfxDWriteFontEntry*>(mFontEntry.get());
+  bool useEmbeddedBitmap =
+      (gfxVars::SystemTextRenderingMode() == DWRITE_RENDERING_MODE_DEFAULT ||
+       forceGDI) &&
+      fe->IsCJKFont() && HasBitmapStrikeForSize(NS_lround(mAdjustedSize));
+
+  const gfxFontStyle* fontStyle = GetStyle();
+  RefPtr<ScaledFont> newScaledFont = Factory::CreateScaledFontForDWriteFont(
+      mFontFace, fontStyle, GetUnscaledFont(), GetAdjustedSize(),
+      useEmbeddedBitmap, ApplySyntheticBold(), forceGDI);
+  if (!newScaledFont) {
+    return nullptr;
+  }
+  InitializeScaledFont(newScaledFont);
+
+  if (forceGDI) {
+    if (mAzureScaledFontGDI.compareExchange(nullptr, newScaledFont.get())) {
+      Unused << newScaledFont.forget();
+      mAzureScaledFontUsedClearType = useClearType;
+    }
+    scaledFont = mAzureScaledFontGDI;
+  } else {
+    if (mAzureScaledFont.compareExchange(nullptr, newScaledFont.get())) {
+      Unused << newScaledFont.forget();
+      mAzureScaledFontUsedClearType = useClearType;
+    }
+    scaledFont = mAzureScaledFont;
+  }
+  return do_AddRef(scaledFont);
+}
+
+bool gfxDWriteFont::ShouldRoundXOffset(cairo_t* aCairo) const {
+  // show_glyphs is implemented on the font and so is used for all Cairo
+  // surface types; however, it may pixel-snap depending on the dwrite
+  // rendering mode
+  return GetMeasuringMode() != DWRITE_MEASURING_MODE_NATURAL;
+}