gecko-dev/gfx/thebes/gfxFT2Fonts.h
Jonathan Kew e92b9e44cf Bug 1449605 - part 1 - Rearrange thebes font code so that the decision whether to apply synthetic-bold is deferred until actually instantiating a font, not made during the font-matching process. r=jwatt
This rearranges how synthetic-bold use is determined in the font selection
& rendering code. Previously, we would decide during the font-selection
algorithm whether we need to apply synthetic-bold to the chosen face, and
then pass that decision through the fontgroup (storing it in the FamilyFace
entries of the mFonts array there) down to the actual rendering code that
instantiates fonts from the faces (font entries) we've selected.

That became a problem for variation fonts because in the case of a user
font, we may not have downloaded the resource yet, so we just have a "user
font container" entry, which carries the descriptors from the @font-face
rule and will fetch the actual resource when needed. But in the case of a
@font-face rule without a weight descriptor, we don't actually know at
font-selection time whether the face will support "true" bold (via a
variation axis) or not, so we can't reliably make the right decision about
applying synthetic bold.

So we now defer that decision until we actually instantiate a platform font
object to shape/measure/draw text. At that point, we have the requested
style and we also have the real font resource, so we can easily determine
whether fake-bold is required.

(This patch should not result in any visible behavior change; that will
come in a second patch now that the architecture supports it.)
2018-05-01 10:30:50 +01:00

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2.8 KiB
C++

/* -*- 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/. */
#ifndef GFX_FT2FONTS_H
#define GFX_FT2FONTS_H
#include "mozilla/MemoryReporting.h"
#include "cairo.h"
#include "gfxTypes.h"
#include "gfxFont.h"
#include "gfxFT2FontBase.h"
#include "gfxContext.h"
#include "gfxFontUtils.h"
#include "gfxUserFontSet.h"
class FT2FontEntry;
class gfxFT2Font : public gfxFT2FontBase {
public: // new functions
gfxFT2Font(const RefPtr<mozilla::gfx::UnscaledFontFreeType>& aUnscaledFont,
cairo_scaled_font_t *aCairoFont,
FT2FontEntry *aFontEntry,
const gfxFontStyle *aFontStyle);
virtual ~gfxFT2Font ();
FT2FontEntry *GetFontEntry();
virtual already_AddRefed<mozilla::gfx::ScaledFont>
GetScaledFont(DrawTarget *aTarget) override;
virtual void AddSizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf,
FontCacheSizes* aSizes) const override;
virtual void AddSizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf,
FontCacheSizes* aSizes) const override;
protected:
struct CachedGlyphData {
CachedGlyphData()
: glyphIndex(0xffffffffU) { }
explicit CachedGlyphData(uint32_t gid)
: glyphIndex(gid) { }
uint32_t glyphIndex;
int32_t lsbDelta;
int32_t rsbDelta;
int32_t xAdvance;
};
const CachedGlyphData* GetGlyphDataForChar(FT_Face aFace, uint32_t ch) {
CharGlyphMapEntryType *entry = mCharGlyphCache.PutEntry(ch);
if (!entry)
return nullptr;
if (entry->mData.glyphIndex == 0xffffffffU) {
// this is a new entry, fill it
FillGlyphDataForChar(aFace, ch, &entry->mData);
}
return &entry->mData;
}
bool ShapeText(DrawTarget *aDrawTarget,
const char16_t *aText,
uint32_t aOffset,
uint32_t aLength,
Script aScript,
bool aVertical,
RoundingFlags aRounding,
gfxShapedText *aShapedText) override;
void FillGlyphDataForChar(FT_Face face, uint32_t ch, CachedGlyphData *gd);
void AddRange(const char16_t *aText,
uint32_t aOffset,
uint32_t aLength,
gfxShapedText *aShapedText);
typedef nsBaseHashtableET<nsUint32HashKey, CachedGlyphData> CharGlyphMapEntryType;
typedef nsTHashtable<CharGlyphMapEntryType> CharGlyphMap;
CharGlyphMap mCharGlyphCache;
};
#endif /* GFX_FT2FONTS_H */