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* Copyright 2019 Google Inc.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
#ifndef sktext_StrikeForGPU_DEFINED
#define sktext_StrikeForGPU_DEFINED
#include "include/core/SkImageInfo.h"
#include "include/core/SkPoint.h"
#include "include/core/SkSpan.h"
#include "include/core/SkTypes.h"
#include "src/core/SkGlyph.h"
#include <memory>
#include <optional>
#include <variant>
class SkDescriptor;
class SkDrawableGlyphBuffer;
class SkReadBuffer;
class SkSourceGlyphBuffer;
class SkStrike;
class SkStrikeCache;
class SkStrikeClient;
class SkStrikeSpec;
class SkWriteBuffer;
struct SkGlyphPositionRoundingSpec;
struct SkScalerContextEffects;
namespace sktext {
// -- SkStrikePromise ------------------------------------------------------------------------------
// SkStrikePromise produces an SkStrike when needed by GPU glyph rendering. In ordinary
// operation, it just wraps an SkStrike. When used for remote glyph cache operation, the promise is
// serialized to an SkDescriptor. When SkStrikePromise is deserialized, it uses the descriptor to
// look up the SkStrike.
// When deserializing some care must be taken; if the needed SkStrike is removed from the cache,
// then looking up using the descriptor will fail resulting in a deserialization failure. The
// Renderer/GPU system solves this problem by pinning all the strikes needed into the cache.
class SkStrikePromise {
SkStrikePromise() = delete;
SkStrikePromise(const SkStrikePromise&) = delete;
SkStrikePromise& operator=(const SkStrikePromise&) = delete;
SkStrikePromise& operator=(SkStrikePromise&&);
explicit SkStrikePromise(sk_sp<SkStrike>&& strike);
explicit SkStrikePromise(const SkStrikeSpec& spec);
static std::optional<SkStrikePromise> MakeFromBuffer(SkReadBuffer& buffer,
const SkStrikeClient* client,
SkStrikeCache* strikeCache);
void flatten(SkWriteBuffer& buffer) const;
// Do what is needed to return a strike.
SkStrike* strike();
// Reset the sk_sp<SkStrike> to nullptr.
void resetStrike();
// Return a descriptor used to look up the SkStrike.
const SkDescriptor& descriptor() const;
std::variant<sk_sp<SkStrike>, std::unique_ptr<SkStrikeSpec>> fStrikeOrSpec;
// -- StrikeForGPU ---------------------------------------------------------------------------------
class StrikeForGPU {
virtual ~StrikeForGPU() = default;
virtual const SkDescriptor& getDescriptor() const = 0;
// Returns the bounding rectangle of the accepted glyphs. Remember for device masks this
// rectangle will be in device space, and for transformed masks this rectangle will be in
// source space.
virtual SkRect prepareForMaskDrawing(
SkDrawableGlyphBuffer* accepted,
SkSourceGlyphBuffer* rejected) = 0;
virtual SkRect prepareForSDFTDrawing(
SkScalar strikeToSourceScale,
SkDrawableGlyphBuffer* accepted,
SkSourceGlyphBuffer* rejected) = 0;
virtual void prepareForPathDrawing(
SkDrawableGlyphBuffer* accepted, SkSourceGlyphBuffer* rejected) = 0;
virtual void prepareForDrawableDrawing(
SkDrawableGlyphBuffer* accepted, SkSourceGlyphBuffer* rejected) = 0;
virtual const SkGlyphPositionRoundingSpec& roundingSpec() const = 0;
// Used with SkScopedStrikeForGPU to take action at the end of a scope.
virtual void onAboutToExitScope() = 0;
// Return underlying SkStrike for building SubRuns while processing glyph runs.
virtual sk_sp<SkStrike> getUnderlyingStrike() const = 0;
// Return a strike promise.
virtual SkStrikePromise strikePromise() = 0;
// Return the maximum dimension of a span of glyphs.
virtual SkScalar findMaximumGlyphDimension(SkSpan<const SkGlyphID> glyphs) = 0;
struct Deleter {
void operator()(StrikeForGPU* ptr) const {
// -- ScopedStrikeForGPU ---------------------------------------------------------------------------
using ScopedStrikeForGPU = std::unique_ptr<StrikeForGPU, StrikeForGPU::Deleter>;
// prepareForPathDrawing uses this union to convert glyph ids to paths.
union IDOrPath {
IDOrPath() {}
// PathOpSubmitter takes care of destroying the paths.
~IDOrPath() {}
SkGlyphID fGlyphID;
SkPath fPath;
// prepareForDrawableDrawing uses this union to convert glyph ids to drawables.
union IDOrDrawable {
SkGlyphID fGlyphID;
SkDrawable* fDrawable;
// -- StrikeForGPUCacheInterface -------------------------------------------------------------------
class StrikeForGPUCacheInterface {
virtual ~StrikeForGPUCacheInterface() = default;
virtual ScopedStrikeForGPU findOrCreateScopedStrike(const SkStrikeSpec& strikeSpec) = 0;
} // namespace sktext
#endif // sktext_StrikeForGPU_DEFINED