1 /*
2  * Copyright 2016 Google Inc.
3  *
4  * Use of this source code is governed by a BSD-style license that can be
5  * found in the LICENSE file.
6  */
7 
8 #ifndef SkImageFilterCache_DEFINED
9 #define SkImageFilterCache_DEFINED
10 
11 #include "SkMatrix.h"
12 #include "SkRefCnt.h"
13 
14 struct SkIPoint;
15 class SkImageFilter;
16 class SkSpecialImage;
17 
18 struct SkImageFilterCacheKey {
SkImageFilterCacheKeySkImageFilterCacheKey19     SkImageFilterCacheKey(const uint32_t uniqueID, const SkMatrix& matrix,
20         const SkIRect& clipBounds, uint32_t srcGenID, const SkIRect& srcSubset)
21         : fUniqueID(uniqueID)
22         , fMatrix(matrix)
23         , fClipBounds(clipBounds)
24         , fSrcGenID(srcGenID)
25         , fSrcSubset(srcSubset) {
26         // Assert that Key is tightly-packed, since it is hashed.
27         static_assert(sizeof(SkImageFilterCacheKey) == sizeof(uint32_t) + sizeof(SkMatrix) +
28                                      sizeof(SkIRect) + sizeof(uint32_t) + 4 * sizeof(int32_t),
29                                      "image_filter_key_tight_packing");
30         fMatrix.getType();  // force initialization of type, so hashes match
31         SkASSERT(fMatrix.isFinite());   // otherwise we can't rely on == self when comparing keys
32     }
33 
34     uint32_t fUniqueID;
35     SkMatrix fMatrix;
36     SkIRect fClipBounds;
37     uint32_t fSrcGenID;
38     SkIRect fSrcSubset;
39 
40     bool operator==(const SkImageFilterCacheKey& other) const {
41         return fUniqueID == other.fUniqueID &&
42                fMatrix == other.fMatrix &&
43                fClipBounds == other.fClipBounds &&
44                fSrcGenID == other.fSrcGenID &&
45                fSrcSubset == other.fSrcSubset;
46     }
47 };
48 
49 // This cache maps from (filter's unique ID + CTM + clipBounds + src bitmap generation ID) to
50 // (result, offset).
51 class SkImageFilterCache : public SkRefCnt {
52 public:
53     enum { kDefaultTransientSize = 32 * 1024 * 1024 };
54 
~SkImageFilterCache()55     virtual ~SkImageFilterCache() {}
56     static SkImageFilterCache* Create(size_t maxBytes);
57     static SkImageFilterCache* Get();
58     virtual sk_sp<SkSpecialImage> get(const SkImageFilterCacheKey& key, SkIPoint* offset) const = 0;
59     virtual void set(const SkImageFilterCacheKey& key, SkSpecialImage* image,
60                      const SkIPoint& offset, const SkImageFilter* filter) = 0;
61     virtual void purge() = 0;
62     virtual void purgeByKeys(const SkImageFilterCacheKey[], int) = 0;
63     SkDEBUGCODE(virtual int count() const = 0;)
64 };
65 
66 #endif
67