commit-bot@chromium.org | 6e3e422 | 2013-11-06 10:08:30 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2013 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 SkCachingPixelRef_DEFINED |
| 9 | #define SkCachingPixelRef_DEFINED |
| 10 | |
| 11 | #include "SkImage.h" |
| 12 | #include "SkPixelRef.h" |
| 13 | |
| 14 | class SkColorTable; |
| 15 | |
| 16 | /** |
| 17 | * PixelRef which defers decoding until SkBitmap::lockPixels() is |
| 18 | * called. Caches the decoded images in the global |
| 19 | * SkScaledImageCache. When the pixels are unlocked, this cache may |
| 20 | * or be destroyed before the next lock. If so, onLockPixels will |
| 21 | * attempt to re-decode. |
| 22 | * |
| 23 | * Decoding is handled by the pure-virtual functions onDecodeInfo() |
| 24 | * and onDecodePixels(). Subclasses of this class need only provide |
| 25 | * those two functions. |
| 26 | */ |
| 27 | class SkCachingPixelRef : public SkPixelRef { |
| 28 | public: |
| 29 | SkCachingPixelRef(); |
| 30 | virtual ~SkCachingPixelRef(); |
| 31 | |
| 32 | protected: |
| 33 | virtual void* onLockPixels(SkColorTable** colorTable) SK_OVERRIDE; |
| 34 | virtual void onUnlockPixels() SK_OVERRIDE; |
| 35 | virtual bool onLockPixelsAreWritable() const SK_OVERRIDE { return false; } |
| 36 | virtual bool onImplementsDecodeInto() SK_OVERRIDE { return true; } |
| 37 | virtual bool onDecodeInto(int pow2, SkBitmap*) SK_OVERRIDE; |
| 38 | |
| 39 | /** |
| 40 | * Configure the supplied bitmap for this pixelRef, based on |
| 41 | * information provided by onDecodeInfo(). Does not set the |
| 42 | * bitmap's pixelRef. */ |
| 43 | bool configure(SkBitmap* bitmap); |
| 44 | |
| 45 | /** |
| 46 | * Cache info from onDecodeInfo(). Returns false on failure. |
| 47 | */ |
| 48 | bool getInfo(SkImageInfo* info); |
| 49 | |
| 50 | /** |
| 51 | * Return some information about the pixels, allowing this class |
| 52 | * to allocate pixels. @return false if anything goes wrong. |
| 53 | */ |
| 54 | virtual bool onDecodeInfo(SkImageInfo* info) = 0; |
| 55 | /** |
| 56 | * Decode into the given pixels, a block of memory of size |
| 57 | * (info.fHeight - 1) * rowBytes + (info.fWidth * bytesPerPixel) |
| 58 | * |
| 59 | * @param info Should be identical to the info returned by |
| 60 | * onDecodeInfo so that the implementation can confirm |
| 61 | * that the caller knows what it is asking for (config, |
| 62 | * size). Thiscontract also allows the caller to specify |
| 63 | * different output-configs, which the implementation can |
| 64 | * decide to support or not. |
| 65 | * |
| 66 | * @return false if anything goes wrong. |
| 67 | */ |
| 68 | virtual bool onDecodePixels(const SkImageInfo& info, |
| 69 | void* pixels, |
| 70 | size_t rowBytes) = 0; |
| 71 | |
| 72 | private: |
| 73 | bool fErrorInDecoding; |
| 74 | void* fScaledCacheId; |
| 75 | SkImageInfo fInfo; |
| 76 | |
| 77 | typedef SkPixelRef INHERITED; |
| 78 | }; |
| 79 | |
| 80 | #endif // SkCachingPixelRef_DEFINED |
| 81 | |