gecko-dev/gfx/thebes/gfxFT2Fonts.cpp

/* -*- 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/. */

#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 "nsUnicodeRange.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,
                      bool            aVertical,
                      RoundingFlags   aRounding,
                      gfxShapedText  *aShapedText)
{
    if (!gfxFont::ShapeText(aDrawTarget, aText, aOffset, aLength, aScript,
                            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;
            bool isClusterStart = charGlyphs[aOffset].IsClusterStart();
            aShapedText->SetGlyphs(aOffset,
                                   CompressedGlyph::MakeComplex(isClusterStart,
                                                                true, 1),
                                   &details);
        }
    }
}

gfxFT2Font::gfxFT2Font(const RefPtr<UnscaledFontFreeType>& aUnscaledFont,
                       cairo_scaled_font_t *aCairoFont,
                       FT2FontEntry *aFontEntry,
                       const gfxFontStyle *aFontStyle,
                       bool aNeedsBold)
    : gfxFT2FontBase(aUnscaledFont, aCairoFont, aFontEntry, aFontStyle)
    , mCharGlyphCache(32)
{
    NS_ASSERTION(mFontEntry, "Unable to find font entry for font.  Something is whack.");
    mApplySyntheticBold = aNeedsBold;
}

gfxFT2Font::~gfxFT2Font()
{
}

already_AddRefed<ScaledFont>
gfxFT2Font::GetScaledFont(DrawTarget *aTarget)
{
    if (!mAzureScaledFont) {
        NativeFont nativeFont;
        nativeFont.mType = NativeFontType::CAIRO_FONT_FACE;
        nativeFont.mFont = GetCairoScaledFont();
        mAzureScaledFont =
            Factory::CreateScaledFontForNativeFont(nativeFont,
                                                   GetUnscaledFont(),
                                                   GetAdjustedSize());
    }

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

void
gfxFT2Font::FillGlyphDataForChar(FT_Face face, uint32_t ch, CachedGlyphData *gd)
{
    if (!face->charmap || face->charmap->encoding != FT_ENCODING_UNICODE) {
        FT_Select_Charmap(face, FT_ENCODING_UNICODE);
    }
    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_Int32 flags = gfxPlatform::GetPlatform()->FontHintingEnabled() ?
                     FT_LOAD_DEFAULT :
                     (FT_LOAD_NO_AUTOHINT | FT_LOAD_NO_HINTING);
    FT_Error err = FT_Load_Glyph(face, gid, flags);

    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;
}

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);
}