gecko-dev/gfx/2d/ScaledFontFontconfig.h
Lee Salzman 4963ce29fb Bug 1773936 - Apply Skia-equivalent subpixel rounding in DrawTargetWebgl. r=aosmond,gfx-reviewers
Depending on the current transform, Skia applies either subpixel rounding or integer
rounding to different coordinate axes of the transformed glyph position. If we don't
correctly predict which of these are applied, we may have aliased cache entries that
round to the same value in DrawTargetWebgl but for which Skia under the hood rounds
in entirely different directions. When this happens, glyphs can get hinted to the
wrong direction. To fix this, we need to ensure that we appropriately apply either
subpixel rounding or integer rounding in the same manner as Skia.

Differential Revision: https://phabricator.services.mozilla.com/D149350
2022-06-16 21:39:07 +00:00

92 lines
2.7 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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 MOZILLA_GFX_SCALEDFONTFONTCONFIG_H_
#define MOZILLA_GFX_SCALEDFONTFONTCONFIG_H_
#include "ScaledFontBase.h"
#include <cairo-ft.h>
namespace mozilla {
namespace gfx {
class NativeFontResourceFontconfig;
class UnscaledFontFontconfig;
class ScaledFontFontconfig : public ScaledFontBase {
public:
MOZ_DECLARE_REFCOUNTED_VIRTUAL_TYPENAME(ScaledFontFontconfig, override)
ScaledFontFontconfig(RefPtr<SharedFTFace>&& aFace, FcPattern* aPattern,
const RefPtr<UnscaledFont>& aUnscaledFont, Float aSize);
FontType GetType() const override { return FontType::FONTCONFIG; }
SkTypeface* CreateSkTypeface() override;
void SetupSkFontDrawOptions(SkFont& aFont) override;
AntialiasMode GetDefaultAAMode() override;
bool UseSubpixelPosition() const override;
bool CanSerialize() override { return true; }
bool MayUseBitmaps() override;
bool GetFontInstanceData(FontInstanceDataOutput aCb, void* aBaton) override;
bool GetWRFontInstanceOptions(
Maybe<wr::FontInstanceOptions>* aOutOptions,
Maybe<wr::FontInstancePlatformOptions>* aOutPlatformOptions,
std::vector<FontVariation>* aOutVariations) override;
bool HasVariationSettings() override;
protected:
cairo_font_face_t* CreateCairoFontFace(
cairo_font_options_t* aFontOptions) override;
private:
friend class NativeFontResourceFontconfig;
friend class UnscaledFontFontconfig;
struct InstanceData {
enum {
AUTOHINT = 1 << 0,
EMBEDDED_BITMAP = 1 << 1,
EMBOLDEN = 1 << 2,
HINT_METRICS = 1 << 3,
LCD_VERTICAL = 1 << 4,
SUBPIXEL_BGR = 1 << 5,
};
explicit InstanceData(FcPattern* aPattern);
InstanceData(const wr::FontInstanceOptions* aOptions,
const wr::FontInstancePlatformOptions* aPlatformOptions);
void SetupFontOptions(cairo_font_options_t* aFontOptions,
int* aOutLoadFlags,
unsigned int* aOutSynthFlags) const;
uint8_t mFlags;
AntialiasMode mAntialias;
FontHinting mHinting;
uint8_t mLcdFilter;
};
ScaledFontFontconfig(RefPtr<SharedFTFace>&& aFace,
const InstanceData& aInstanceData,
const RefPtr<UnscaledFont>& aUnscaledFont, Float aSize);
RefPtr<SharedFTFace> mFace;
InstanceData mInstanceData;
};
} // namespace gfx
} // namespace mozilla
#endif /* MOZILLA_GFX_SCALEDFONTFONTCONFIG_H_ */