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* Copyright 2018 Google Inc.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
#ifndef SkRemoteGlyphCache_DEFINED
#define SkRemoteGlyphCache_DEFINED
#include <memory>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <vector>
#include "../private/SkTHash.h"
#include "SkData.h"
#include "SkDevice.h"
#include "SkDrawLooper.h"
#include "SkMakeUnique.h"
#include "SkNoDrawCanvas.h"
#include "SkRefCnt.h"
#include "SkSerialProcs.h"
#include "SkStrikeInterface.h"
#include "SkTypeface.h"
class Serializer;
enum SkAxisAlignment : uint32_t;
class SkDescriptor;
class SkStrike;
struct SkPackedGlyphID;
enum SkScalerContextFlags : uint32_t;
class SkStrikeCache;
class SkTypefaceProxy;
struct WireTypeface;
class SkStrikeServer;
struct SkDescriptorMapOperators {
size_t operator()(const SkDescriptor* key) const;
bool operator()(const SkDescriptor* lhs, const SkDescriptor* rhs) const;
template <typename T>
using SkDescriptorMap = std::unordered_map<const SkDescriptor*, T, SkDescriptorMapOperators,
using SkDescriptorSet =
std::unordered_set<const SkDescriptor*, SkDescriptorMapOperators, SkDescriptorMapOperators>;
// A SkTextBlobCacheDiffCanvas is used to populate the SkStrikeServer with ops
// which will be serialized and renderered using the SkStrikeClient.
class SK_API SkTextBlobCacheDiffCanvas : public SkNoDrawCanvas {
struct SK_API Settings {
bool fContextSupportsDistanceFieldText = true;
SkScalar fMinDistanceFieldFontSize = -1.f;
SkScalar fMaxDistanceFieldFontSize = -1.f;
int fMaxTextureSize = 0;
size_t fMaxTextureBytes = 0u;
SkTextBlobCacheDiffCanvas(int width, int height, const SkSurfaceProps& props,
SkStrikeServer* strikeServer, Settings settings = Settings());
SkTextBlobCacheDiffCanvas(int width, int height, const SkSurfaceProps& props,
SkStrikeServer* strikeServer, sk_sp<SkColorSpace> colorSpace,
Settings settings = Settings());
~SkTextBlobCacheDiffCanvas() override;
SkCanvas::SaveLayerStrategy getSaveLayerStrategy(const SaveLayerRec& rec) override;
bool onDoSaveBehind(const SkRect*) override;
void onDrawTextBlob(const SkTextBlob* blob, SkScalar x, SkScalar y,
const SkPaint& paint) override;
class TrackLayerDevice;
static SkScalar SetupForPath(SkPaint* paint, SkFont* font);
using SkDiscardableHandleId = uint32_t;
// This class is not thread-safe.
class SK_API SkStrikeServer final : public SkStrikeCacheInterface {
// An interface used by the server to create handles for pinning SkStrike
// entries on the remote client.
class SK_API DiscardableHandleManager {
virtual ~DiscardableHandleManager() = default;
// Creates a new *locked* handle and returns a unique ID that can be used to identify
// it on the remote client.
virtual SkDiscardableHandleId createHandle() = 0;
// Returns true if the handle could be successfully locked. The server can
// assume it will remain locked until the next set of serialized entries is
// pulled from the SkStrikeServer.
// If returns false, the cache entry mapped to the handle has been deleted
// on the client. Any subsequent attempts to lock the same handle are not
// allowed.
virtual bool lockHandle(SkDiscardableHandleId) = 0;
// Returns true if a handle has been deleted on the remote client. It is
// invalid to use a handle id again with this manager once this returns true.
// TODO(khushalsagar): Make pure virtual once chrome implementation lands.
virtual bool isHandleDeleted(SkDiscardableHandleId) { return false; }
explicit SkStrikeServer(DiscardableHandleManager* discardableHandleManager);
~SkStrikeServer() override;
// Serializes the typeface to be remoted using this server.
sk_sp<SkData> serializeTypeface(SkTypeface*);
// Serializes the strike data captured using a SkTextBlobCacheDiffCanvas. Any
// handles locked using the DiscardableHandleManager will be assumed to be
// unlocked after this call.
void writeStrikeData(std::vector<uint8_t>* memory);
// Methods used internally in skia ------------------------------------------
class SkGlyphCacheState;
SkGlyphCacheState* getOrCreateCache(const SkPaint&,
const SkFont& font,
const SkSurfaceProps&,
const SkMatrix&,
SkScalerContextFlags flags,
SkScalerContextEffects* effects);
SkScopedStrike findOrCreateScopedStrike(const SkDescriptor& desc,
const SkScalerContextEffects& effects,
const SkTypeface& typeface) override;
void setMaxEntriesInDescriptorMapForTesting(size_t count) {
fMaxEntriesInDescriptorMap = count;
size_t remoteGlyphStateMapSizeForTesting() const { return fRemoteGlyphStateMap.size(); }
static constexpr size_t kMaxEntriesInDescriptorMap = 2000u;
void checkForDeletedEntries();
SkGlyphCacheState* getOrCreateCache(const SkDescriptor& desc,
const SkTypeface& typeface,
SkScalerContextEffects effects);
SkDescriptorMap<std::unique_ptr<SkGlyphCacheState>> fRemoteGlyphStateMap;
DiscardableHandleManager* const fDiscardableHandleManager;
SkTHashSet<SkFontID> fCachedTypefaces;
size_t fMaxEntriesInDescriptorMap = kMaxEntriesInDescriptorMap;
// Cached serialized typefaces.
SkTHashMap<SkFontID, sk_sp<SkData>> fSerializedTypefaces;
// State cached until the next serialization.
SkDescriptorSet fLockedDescs;
std::vector<WireTypeface> fTypefacesToSend;
class SK_API SkStrikeClient {
// This enum is used in histogram reporting in chromium. Please don't re-order the list of
// entries, and consider it to be append-only.
enum CacheMissType : uint32_t {
// Hard failures where no fallback could be found.
kFontMetrics = 0,
kGlyphMetrics = 1,
kGlyphImage = 2,
kGlyphPath = 3,
// The original glyph could not be found and a fallback was used.
kGlyphMetricsFallback = 4,
kGlyphPathFallback = 5,
kLast = kGlyphPathFallback
// An interface to delete handles that may be pinned by the remote server.
class DiscardableHandleManager : public SkRefCnt {
virtual ~DiscardableHandleManager() = default;
// Returns true if the handle was unlocked and can be safely deleted. Once
// successful, subsequent attempts to delete the same handle are invalid.
virtual bool deleteHandle(SkDiscardableHandleId) = 0;
virtual void notifyCacheMiss(CacheMissType) {}
explicit SkStrikeClient(sk_sp<DiscardableHandleManager>,
bool isLogging = true,
SkStrikeCache* strikeCache = nullptr);
// Deserializes the typeface previously serialized using the SkStrikeServer. Returns null if the
// data is invalid.
sk_sp<SkTypeface> deserializeTypeface(const void* data, size_t length);
// Deserializes the strike data from a SkStrikeServer. All messages generated
// from a server when serializing the ops must be deserialized before the op
// is rasterized.
// Returns false if the data is invalid.
bool readStrikeData(const volatile void* memory, size_t memorySize);
class DiscardableStrikePinner;
sk_sp<SkTypeface> addTypeface(const WireTypeface& wire);
SkTHashMap<SkFontID, sk_sp<SkTypeface>> fRemoteFontIdToTypeface;
sk_sp<DiscardableHandleManager> fDiscardableHandleManager;
SkStrikeCache* const fStrikeCache;
const bool fIsLogging;
#endif // SkRemoteGlyphCache_DEFINED