SkImage.h revision d49226cff368419c4a0fed7ba7f0383d46d9b2ac
1/* 2 * Copyright 2012 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 SkImage_DEFINED 9#define SkImage_DEFINED 10 11#include "SkImageInfo.h" 12#include "SkImageEncoder.h" 13#include "SkRefCnt.h" 14#include "SkScalar.h" 15#include "SkShader.h" 16 17class SkData; 18class SkCanvas; 19class SkImageGenerator; 20class SkPaint; 21class GrContext; 22class GrTexture; 23 24/** 25 * SkImage is an abstraction for drawing a rectagle of pixels, though the 26 * particular type of image could be actually storing its data on the GPU, or 27 * as drawing commands (picture or PDF or otherwise), ready to be played back 28 * into another canvas. 29 * 30 * The content of SkImage is always immutable, though the actual storage may 31 * change, if for example that image can be re-created via encoded data or 32 * other means. 33 */ 34class SK_API SkImage : public SkRefCnt { 35public: 36 SK_DECLARE_INST_COUNT(SkImage) 37 38 typedef SkImageInfo Info; 39 40 static SkImage* NewRasterCopy(const Info&, const void* pixels, size_t rowBytes); 41 static SkImage* NewRasterData(const Info&, SkData* pixels, size_t rowBytes); 42 43 /** 44 * GrTexture is a more logical parameter for this factory, but its 45 * interactions with scratch cache still has issues, so for now we take 46 * SkBitmap instead. This will be changed in the future. skbug.com/1449 47 */ 48 static SkImage* NewTexture(const SkBitmap&); 49 50 virtual bool isOpaque() const { return false; } 51 52 /** 53 * Construct a new SkImage based on the given ImageGenerator. 54 * This function will always take ownership of the passed 55 * ImageGenerator. Returns NULL on error. 56 */ 57 static SkImage* NewFromGenerator(SkImageGenerator*); 58 59 int width() const { return fWidth; } 60 int height() const { return fHeight; } 61 uint32_t uniqueID() const { return fUniqueID; } 62 63 /** 64 * Return the GrTexture that stores the image pixels. Calling getTexture 65 * does not affect the reference count of the GrTexture object. 66 * Will return NULL if the image does not use a texture. 67 */ 68 GrTexture* getTexture(); 69 70 virtual SkShader* newShader(SkShader::TileMode, 71 SkShader::TileMode, 72 const SkMatrix* localMatrix = NULL) const; 73 74 void draw(SkCanvas*, SkScalar x, SkScalar y, const SkPaint*) const; 75 76 /** 77 * Draw the image, cropped to the src rect, to the dst rect of a canvas. 78 * If src is larger than the bounds of the image, the rest of the image is 79 * filled with transparent black pixels. 80 * 81 * See SkCanvas::drawBitmapRectToRect for similar behavior. 82 */ 83 void draw(SkCanvas*, const SkRect* src, const SkRect& dst, const SkPaint*) const; 84 85 /** 86 * If the image has direct access to its pixels (i.e. they are in local 87 * RAM) return the (const) address of those pixels, and if not null, return 88 * the ImageInfo and rowBytes. The returned address is only valid while 89 * the image object is in scope. 90 * 91 * On failure, returns NULL and the info and rowBytes parameters are 92 * ignored. 93 */ 94 const void* peekPixels(SkImageInfo* info, size_t* rowBytes) const; 95 96 /** 97 * Encode the image's pixels and return the result as a new SkData, which 98 * the caller must manage (i.e. call unref() when they are done). 99 * 100 * If the image type cannot be encoded, or the requested encoder type is 101 * not supported, this will return NULL. 102 */ 103 SkData* encode(SkImageEncoder::Type t = SkImageEncoder::kPNG_Type, 104 int quality = 80) const; 105 106protected: 107 SkImage(int width, int height) : 108 fWidth(width), 109 fHeight(height), 110 fUniqueID(NextUniqueID()) { 111 112 SkASSERT(width >= 0); 113 SkASSERT(height >= 0); 114 } 115 116private: 117 const int fWidth; 118 const int fHeight; 119 const uint32_t fUniqueID; 120 121 static uint32_t NextUniqueID(); 122 123 typedef SkRefCnt INHERITED; 124 125 /** 126 * Return a copy of the image's pixels, limiting them to the subset 127 * rectangle's intersection wit the image bounds. If subset is NULL, then 128 * the entire image will be considered. 129 * 130 * If the bitmap's pixels have already been allocated, then readPixels() 131 * will succeed only if it can support converting the image's pixels into 132 * the bitmap's ColorType/AlphaType. Any pixels in the bitmap that do not 133 * intersect with the image's bounds and the subset (if not null) will be 134 * left untouched. 135 * 136 * If the bitmap is initially empty/unallocated, then it will be allocated 137 * using the default allocator, and the ColorType/AlphaType will be chosen 138 * to most closely fit the image's configuration. 139 * 140 * On failure, false will be returned, and bitmap will unmodified. 141 */ 142 // On ice for now: 143 // - should it respect the particular colortype/alphatype of the src 144 // - should it have separate entrypoints for preallocated and not bitmaps? 145 // - isn't it enough to allow the caller to draw() the image into a canvas? 146 bool readPixels(SkBitmap* bitmap, const SkIRect* subset = NULL) const; 147}; 148 149#endif 150