gfx/thebes/gfxDWriteFonts.cpp
author Nika Layzell <nika@thelayzells.com>
Tue, 25 Sep 2018 17:34:53 +0200
changeset 504874 e0f95dd96d5458f60980f1e8b3f846beed6e5817
parent 504743 c8141cbb7ede93f9111de7dec9e0bf9a7e984bd2
child 504886 9bfe29337ffe3d93cd060077e2e999e72bb9b7cf
permissions -rw-r--r--
Bug 1448426 - Wrap windows.h to avoid problematic define statements, r=froydnj,glandium By default, windows.h exposes a large number of problematic define statements which are UpperCamelCase, such as a define from `CreateWindow` to `CreateWindow{A,W}`. As many of these names are generic (e.g. CreateFile, CreateWindow), they can mess up Gecko code that may legitimately have its own methods with the same names. The header also defines some traditional SCREAMING_SNAKE_CASE defines which can mess up our code by conflicting with local values. This patch adds a simple code generator which generates wrappers for these defines, and uses them to wrap the windows.h wrapper using the `stl_wrappers` mechanism, allowing us to use windows.h in more places. Differential Revision: https://phabricator.services.mozilla.com/D10932

/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * 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 "gfxTextRun.h"
#include "mozilla/gfx/gfxVars.h"

#include "harfbuzz/hb.h"
#include "mozilla/FontPropertyTypes.h"
#include "cairo-win32.h"

using namespace mozilla;
using namespace mozilla::gfx;

// This is also in gfxGDIFont.cpp. Would be nice to put it somewhere common,
// but we can't declare it in the gfxFont.h or gfxFontUtils.h headers
// because those are exported, and the cairo headers aren't.
static inline cairo_antialias_t
GetCairoAntialiasOption(gfxFont::AntialiasOption anAntialiasOption)
{
    switch (anAntialiasOption) {
    default:
    case gfxFont::kAntialiasDefault:
        return CAIRO_ANTIALIAS_DEFAULT;
    case gfxFont::kAntialiasNone:
        return CAIRO_ANTIALIAS_NONE;
    case gfxFont::kAntialiasGrayscale:
        return CAIRO_ANTIALIAS_GRAY;
    case gfxFont::kAntialiasSubpixel:
        return CAIRO_ANTIALIAS_SUBPIXEL;
    }
}

// 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;
}

////////////////////////////////////////////////////////////////////////////////
// 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())
    , mCairoFontFace(nullptr)
    , mMetrics(nullptr)
    , mSpaceGlyph(0)
    , 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));

    ComputeMetrics(anAAOption);
}

gfxDWriteFont::~gfxDWriteFont()
{
    if (mCairoFontFace) {
        cairo_font_face_destroy(mCairoFontFace);
    }
    if (mScaledFont) {
        cairo_scaled_font_destroy(mScaledFont);
    }
    delete mMetrics;
}

static void ForceFontUpdate()
{
  // update device context font cache
  // Dirty but easiest way:
  // Changing nsIPrefBranch entry which triggers callbacks
  // and flows into calling mDeviceContext->FlushFontCache()
  // to update the font cache in all the instance of Browsers
  static const char kPrefName[] = "font.internaluseonly.changed";
  bool fontInternalChange =
    Preferences::GetBool(kPrefName, false);
  Preferences::SetBool(kPrefName, !fontInternalChange);
}

void
gfxDWriteFont::UpdateSystemTextQuality()
{
  BYTE newQuality = GetSystemTextQuality();
  if (gfxVars::SystemTextQuality() != newQuality) {
    gfxVars::SetSystemTextQuality(newQuality);
  }
}

void
gfxDWriteFont::SystemTextQualityChanged()
{
  // If ClearType status has changed, update our value,
  // flush cached stuff that depended on the old setting, and force
  // reflow everywhere to ensure we are using correct glyph metrics.
  ForceFontUpdate();
  Factory::SetSystemTextQuality(gfxVars::SystemTextQuality());
  gfxPlatform::FlushFontAndWordCaches();
  gfxPlatform::ForceGlobalReflow();
}

UniquePtr<gfxFont>
gfxDWriteFont::CopyWithAntialiasOption(AntialiasOption anAAOption)
{
    auto entry = static_cast<gfxDWriteFontEntry*>(mFontEntry.get());
    RefPtr<UnscaledFontDWrite> unscaledFont = static_cast<UnscaledFontDWrite*>(mUnscaledFont.get());
    return MakeUnique<gfxDWriteFont>(unscaledFont, entry, &mStyle, mFontFace, anAAOption);
}

const gfxFont::Metrics&
gfxDWriteFont::GetHorizontalMetrics()
{
    return *mMetrics;
}

bool
gfxDWriteFont::GetFakeMetricsForArialBlack(DWRITE_FONT_METRICS *aFontMetrics)
{
    gfxFontStyle style(mStyle);
    style.weight = FontWeight(700);

    gfxFontEntry* fe =
        gfxPlatformFontList::PlatformFontList()->
            FindFontForFamily(NS_LITERAL_CSTRING("Arial"), &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)
{
    DWRITE_FONT_METRICS fontMetrics;
    if (!(mFontEntry->Weight().Min() == FontWeight(900) &&
          mFontEntry->Weight().Max() == FontWeight(900) &&
          !mFontEntry->IsUserFont() &&
          mFontEntry->Name().EqualsLiteral("Arial Black") &&
          GetFakeMetricsForArialBlack(&fontMetrics)))
    {
        mFontFace->GetMetrics(&fontMetrics);
    }

    if (mStyle.sizeAdjust >= 0.0) {
        gfxFloat aspect = (gfxFloat)fontMetrics.xHeight /
                   fontMetrics.designUnitsPerEm;
        mAdjustedSize = mStyle.GetAdjustedSize(aspect);
    } else {
        mAdjustedSize = mStyle.size;
    }

    // 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
    }

    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 = new gfxFont::Metrics;
    ::memset(mMetrics, 0, sizeof(*mMetrics));

    mFUnitsConvFactor = float(mAdjustedSize / fontMetrics.designUnitsPerEm);

    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;
    HRESULT hr = mFontFace->GetGlyphIndices(&ucs, 1, &glyph);
    if (FAILED(hr)) {
        mMetrics->spaceWidth = 0;
    } else {
        mSpaceGlyph = glyph;
        mMetrics->spaceWidth = MeasureGlyphWidth(glyph);
    }

    // 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) {
        ucs = L'x';
        if (SUCCEEDED(mFontFace->GetGlyphIndices(&ucs, 1, &glyph))) {
            mMetrics->aveCharWidth = MeasureGlyphWidth(glyph);
        }
        if (mMetrics->aveCharWidth < 1) {
            // Let's just assume the X is square.
            mMetrics->aveCharWidth = fontMetrics.xHeight * mFUnitsConvFactor;
        }
    }

    ucs = L'0';
    if (SUCCEEDED(mFontFace->GetGlyphIndices(&ucs, 1, &glyph))) {
        mMetrics->zeroOrAveCharWidth = MeasureGlyphWidth(glyph);
    }
    if (mMetrics->zeroOrAveCharWidth < 1) {
        mMetrics->zeroOrAveCharWidth = mMetrics->aveCharWidth;
    }

    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 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 zeroOrAve: %f\n",
           mMetrics->spaceWidth, mMetrics->aveCharWidth, mMetrics->zeroOrAveCharWidth);
    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;
}

uint32_t
gfxDWriteFont::GetSpaceGlyph()
{
    return mSpaceGlyph;
}

bool
gfxDWriteFont::SetupCairoFont(DrawTarget* aDrawTarget)
{
    cairo_scaled_font_t *scaledFont = InitCairoScaledFont();
    if (cairo_scaled_font_status(scaledFont) != CAIRO_STATUS_SUCCESS) {
        // Don't cairo_set_scaled_font as that would propagate the error to
        // the cairo_t, precluding any further drawing.
        return false;
    }
    cairo_set_scaled_font(gfxFont::RefCairo(aDrawTarget), scaledFont);
    return true;
}

bool
gfxDWriteFont::IsValid() const
{
    return mFontFace != nullptr;
}

IDWriteFontFace*
gfxDWriteFont::GetFontFace()
{
    return  mFontFace.get();
}

cairo_font_face_t *
gfxDWriteFont::CairoFontFace()
{
    if (!mCairoFontFace) {
#ifdef CAIRO_HAS_DWRITE_FONT
        mCairoFontFace = 
            cairo_dwrite_font_face_create_for_dwrite_fontface(
            ((gfxDWriteFontEntry*)mFontEntry.get())->mFont, mFontFace);
#endif
    }
    return mCairoFontFace;
}


cairo_scaled_font_t *
gfxDWriteFont::InitCairoScaledFont()
{
    if (!mScaledFont) {
        cairo_matrix_t sizeMatrix;
        cairo_matrix_t identityMatrix;

        cairo_matrix_init_scale(&sizeMatrix, mAdjustedSize, mAdjustedSize);
        cairo_matrix_init_identity(&identityMatrix);

        cairo_font_options_t *fontOptions = cairo_font_options_create();

        if (mAntialiasOption != kAntialiasDefault) {
            cairo_font_options_set_antialias(fontOptions,
                GetCairoAntialiasOption(mAntialiasOption));
        }

        mScaledFont = cairo_scaled_font_create(CairoFontFace(),
                                                    &sizeMatrix,
                                                    &identityMatrix,
                                                    fontOptions);
        cairo_font_options_destroy(fontOptions);

        cairo_dwrite_scaled_font_allow_manual_show_glyphs(mScaledFont,
                                                          mAllowManualShowGlyphs);

        cairo_dwrite_scaled_font_set_force_GDI_classic(mScaledFont,
                                                       GetForceGDIClassic());
    }

    NS_ASSERTION(mAdjustedSize == 0.0 ||
                 cairo_scaled_font_status(mScaledFont) 
                   == CAIRO_STATUS_SUCCESS,
                 "Failed to make scaled font");

    return mScaledFont;
}

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() &&
            !mStyle.variationSettings.IsEmpty());
}

int32_t
gfxDWriteFont::GetGlyphWidth(DrawTarget& aDrawTarget, uint16_t aGID)
{
    if (!mGlyphWidths) {
        mGlyphWidths = MakeUnique<nsDataHashtable<nsUint32HashKey,int32_t>>(128);
    }

    int32_t width = -1;
    if (mGlyphWidths->Get(aGID, &width)) {
        return width;
    }

    width = NS_lround(MeasureGlyphWidth(aGID) * 65536.0);
    mGlyphWidths->Put(aGID, width);
    return width;
}

bool
gfxDWriteFont::GetForceGDIClassic()
{
    return static_cast<gfxDWriteFontEntry*>(mFontEntry.get())->GetForceGDIClassic() &&
         cairo_dwrite_get_cleartype_rendering_mode() < 0 &&
         GetAdjustedSize() <=
            gfxDWriteFontList::PlatformFontList()->GetForceGDIClassicMaxFontSize();
}

DWRITE_MEASURING_MODE
gfxDWriteFont::GetMeasuringMode()
{
    return GetForceGDIClassic()
        ? DWRITE_MEASURING_MODE_GDI_CLASSIC
        : gfxWindowsPlatform::GetPlatform()->DWriteMeasuringMode();
}

gfxFloat
gfxDWriteFont::MeasureGlyphWidth(uint16_t aGlyph)
{
    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);
            }
        }
    }
    return 0;
}

void
gfxDWriteFont::AddSizeOfExcludingThis(MallocSizeOf aMallocSizeOf,
                                      FontCacheSizes* aSizes) const
{
    gfxFont::AddSizeOfExcludingThis(aMallocSizeOf, aSizes);
    aSizes->mFontInstances += aMallocSizeOf(mMetrics);
    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(mozilla::gfx::DrawTarget *aTarget)
{
    if (mAzureScaledFontUsedClearType != UsingClearType()) {
        mAzureScaledFont = nullptr;
    }
    if (!mAzureScaledFont) {
        gfxDWriteFontEntry *fe =
            static_cast<gfxDWriteFontEntry*>(mFontEntry.get());
        bool useEmbeddedBitmap =
            fe->IsCJKFont() &&
            HasBitmapStrikeForSize(NS_lround(mAdjustedSize));
        bool forceGDI = GetForceGDIClassic();

        IDWriteRenderingParams* params = gfxWindowsPlatform::GetPlatform()->GetRenderingParams(
            UsingClearType() ?
                (forceGDI ?
                    gfxWindowsPlatform::TEXT_RENDERING_GDI_CLASSIC :
                    gfxWindowsPlatform::TEXT_RENDERING_NORMAL) :
                gfxWindowsPlatform::TEXT_RENDERING_NO_CLEARTYPE);

        const gfxFontStyle* fontStyle = GetStyle();
        mAzureScaledFont =
            Factory::CreateScaledFontForDWriteFont(mFontFace, fontStyle,
                                                   GetUnscaledFont(),
                                                   GetAdjustedSize(),
                                                   useEmbeddedBitmap,
                                                   forceGDI,
                                                   params,
                                                   params->GetGamma(),
                                                   params->GetEnhancedContrast());
        if (!mAzureScaledFont) {
            return nullptr;
        }
        InitializeScaledFont();
        mAzureScaledFontUsedClearType = UsingClearType();
    }

    if (aTarget->GetBackendType() == BackendType::CAIRO) {
        if (!mAzureScaledFont->GetCairoScaledFont()) {
            cairo_scaled_font_t* cairoScaledFont = InitCairoScaledFont();
            if (!cairoScaledFont) {
                return nullptr;
            }
            mAzureScaledFont->SetCairoScaledFont(cairoScaledFont);
        }
    }

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