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 SkImageGenerator_DEFINED 9 #define SkImageGenerator_DEFINED 10 11 #include "SkImageInfo.h" 12 #include "SkColor.h" 13 14 class SkBitmap; 15 class SkData; 16 class SkImageGenerator; 17 18 /** 19 * Takes ownership of SkImageGenerator. If this method fails for 20 * whatever reason, it will return false and immediatetely delete 21 * the generator. If it succeeds, it will modify destination 22 * bitmap. 23 * 24 * If generator is NULL, will safely return false. 25 * 26 * If this fails or when the SkDiscardablePixelRef that is 27 * installed into destination is destroyed, it will call 28 * SkDELETE() on the generator. Therefore, generator should be 29 * allocated with SkNEW() or SkNEW_ARGS(). 30 * 31 * @param destination Upon success, this bitmap will be 32 * configured and have a pixelref installed. 33 * 34 * @return true iff successful. 35 */ 36 SK_API bool SkInstallDiscardablePixelRef(SkImageGenerator*, SkBitmap* destination); 37 38 /** 39 * Purges all unlocked discardable memory in Skia's global 40 * discardable memory pool. 41 */ 42 SK_API void SkPurgeGlobalDiscardableMemoryPool(); 43 44 45 /** 46 * An interface that allows a purgeable PixelRef (such as a 47 * SkDiscardablePixelRef) to decode and re-decode an image as needed. 48 */ 49 class SK_API SkImageGenerator { 50 public: 51 /** 52 * The PixelRef which takes ownership of this SkImageGenerator 53 * will call the image generator's destructor. 54 */ ~SkImageGenerator()55 virtual ~SkImageGenerator() { } 56 57 #ifdef SK_SUPPORT_LEGACY_IMAGEGENERATORAPI refEncodedData()58 virtual SkData* refEncodedData() { return this->onRefEncodedData(); } getInfo(SkImageInfo * info)59 virtual bool getInfo(SkImageInfo* info) { return this->onGetInfo(info); } getPixels(const SkImageInfo & info,void * pixels,size_t rowBytes)60 virtual bool getPixels(const SkImageInfo& info, void* pixels, size_t rowBytes) { 61 return this->onGetPixels(info, pixels, rowBytes, NULL, NULL); 62 } 63 #else 64 /** 65 * Return a ref to the encoded (i.e. compressed) representation, 66 * of this data. 67 * 68 * If non-NULL is returned, the caller is responsible for calling 69 * unref() on the data when it is finished. 70 */ refEncodedData()71 SkData* refEncodedData() { return this->onRefEncodedData(); } 72 73 /** 74 * Return some information about the image, allowing the owner of 75 * this object to allocate pixels. 76 * 77 * Repeated calls to this function should give the same results, 78 * allowing the PixelRef to be immutable. 79 * 80 * @return false if anything goes wrong. 81 */ 82 bool getInfo(SkImageInfo* info); 83 84 /** 85 * Decode into the given pixels, a block of memory of size at 86 * least (info.fHeight - 1) * rowBytes + (info.fWidth * 87 * bytesPerPixel) 88 * 89 * Repeated calls to this function should give the same results, 90 * allowing the PixelRef to be immutable. 91 * 92 * @param info A description of the format (config, size) 93 * expected by the caller. This can simply be identical 94 * to the info returned by getInfo(). 95 * 96 * This contract also allows the caller to specify 97 * different output-configs, which the implementation can 98 * decide to support or not. 99 * 100 * If info is kIndex8_SkColorType, then the caller must provide storage for up to 256 101 * SkPMColor values in ctable. On success the generator must copy N colors into that storage, 102 * (where N is the logical number of table entries) and set ctableCount to N. 103 * 104 * If info is not kIndex8_SkColorType, then the last two parameters may be NULL. If ctableCount 105 * is not null, it will be set to 0. 106 * 107 * @return false if anything goes wrong or if the image info is 108 * unsupported. 109 */ 110 bool getPixels(const SkImageInfo& info, void* pixels, size_t rowBytes, 111 SkPMColor ctable[], int* ctableCount); 112 113 /** 114 * Simplified version of getPixels() that asserts that info is NOT kIndex8_SkColorType. 115 */ 116 bool getPixels(const SkImageInfo& info, void* pixels, size_t rowBytes); 117 #endif 118 119 protected: 120 virtual SkData* onRefEncodedData(); 121 virtual bool onGetInfo(SkImageInfo* info); 122 virtual bool onGetPixels(const SkImageInfo& info, 123 void* pixels, size_t rowBytes, 124 SkPMColor ctable[], int* ctableCount); 125 }; 126 127 #endif // SkImageGenerator_DEFINED 128