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 "SkDiscardableMemory.h" 12 #include "SkImageInfo.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 this fails or when the SkDiscardablePixelRef that is 25 * installed into destination is destroyed, it will call 26 * SkDELETE() on the generator. Therefore, generator should be 27 * allocated with SkNEW() or SkNEW_ARGS(). 28 * 29 * @param destination Upon success, this bitmap will be 30 * configured and have a pixelref installed. 31 * 32 * @param factory If not NULL, this object will be used as a 33 * source of discardable memory when decoding. If NULL, then 34 * SkDiscardableMemory::Create() will be called. 35 * 36 * @return true iff successful. 37 */ 38 SK_API bool SkInstallDiscardablePixelRef(SkImageGenerator* generator, 39 SkBitmap* destination, 40 SkDiscardableMemory::Factory* factory = NULL); 41 42 43 /** 44 * An interface that allows a purgeable PixelRef (such as a 45 * SkDiscardablePixelRef) to decode and re-decode an image as needed. 46 */ 47 class SK_API SkImageGenerator { 48 public: 49 /** 50 * The PixelRef which takes ownership of this SkImageGenerator 51 * will call the image generator's destructor. 52 */ ~SkImageGenerator()53 virtual ~SkImageGenerator() { } 54 55 /** 56 * Return a ref to the encoded (i.e. compressed) representation, 57 * of this data. 58 * 59 * If non-NULL is returned, the caller is responsible for calling 60 * unref() on the data when it is finished. 61 */ refEncodedData()62 virtual SkData* refEncodedData() { return NULL; } 63 64 /** 65 * Return some information about the image, allowing the owner of 66 * this object to allocate pixels. 67 * 68 * Repeated calls to this function should give the same results, 69 * allowing the PixelRef to be immutable. 70 * 71 * @return false if anything goes wrong. 72 */ 73 virtual bool getInfo(SkImageInfo* info) = 0; 74 75 /** 76 * Decode into the given pixels, a block of memory of size at 77 * least (info.fHeight - 1) * rowBytes + (info.fWidth * 78 * bytesPerPixel) 79 * 80 * Repeated calls to this function should give the same results, 81 * allowing the PixelRef to be immutable. 82 * 83 * @param info A description of the format (config, size) 84 * expected by the caller. This can simply be identical 85 * to the info returned by getInfo(). 86 * 87 * This contract also allows the caller to specify 88 * different output-configs, which the implementation can 89 * decide to support or not. 90 * 91 * @return false if anything goes wrong or if the image info is 92 * unsupported. 93 */ 94 virtual bool getPixels(const SkImageInfo& info, 95 void* pixels, 96 size_t rowBytes) = 0; 97 }; 98 99 #endif // SkImageGenerator_DEFINED 100