1 /* 2 * Copyright 2007 The Android Open Source Project 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 SkPicture_DEFINED 9 #define SkPicture_DEFINED 10 11 #include "include/core/SkRect.h" 12 #include "include/core/SkRefCnt.h" 13 #include "include/core/SkTileMode.h" 14 #include "include/core/SkTypes.h" 15 16 class SkCanvas; 17 class SkData; 18 struct SkDeserialProcs; 19 class SkImage; 20 class SkMatrix; 21 struct SkSerialProcs; 22 class SkShader; 23 class SkStream; 24 class SkWStream; 25 26 /** \class SkPicture 27 SkPicture records drawing commands made to SkCanvas. The command stream may be 28 played in whole or in part at a later time. 29 30 SkPicture is an abstract class. SkPicture may be generated by SkPictureRecorder 31 or SkDrawable, or from SkPicture previously saved to SkData or SkStream. 32 33 SkPicture may contain any SkCanvas drawing command, as well as one or more 34 SkCanvas matrix or SkCanvas clip. SkPicture has a cull SkRect, which is used as 35 a bounding box hint. To limit SkPicture bounds, use SkCanvas clip when 36 recording or drawing SkPicture. 37 */ 38 class SK_API SkPicture : public SkRefCnt { 39 public: 40 41 /** Recreates SkPicture that was serialized into a stream. Returns constructed SkPicture 42 if successful; otherwise, returns nullptr. Fails if data does not permit 43 constructing valid SkPicture. 44 45 procs->fPictureProc permits supplying a custom function to decode SkPicture. 46 If procs->fPictureProc is nullptr, default decoding is used. procs->fPictureCtx 47 may be used to provide user context to procs->fPictureProc; procs->fPictureProc 48 is called with a pointer to data, data byte length, and user context. 49 50 @param stream container for serial data 51 @param procs custom serial data decoders; may be nullptr 52 @return SkPicture constructed from stream data 53 */ 54 static sk_sp<SkPicture> MakeFromStream(SkStream* stream, 55 const SkDeserialProcs* procs = nullptr); 56 57 /** Recreates SkPicture that was serialized into data. Returns constructed SkPicture 58 if successful; otherwise, returns nullptr. Fails if data does not permit 59 constructing valid SkPicture. 60 61 procs->fPictureProc permits supplying a custom function to decode SkPicture. 62 If procs->fPictureProc is nullptr, default decoding is used. procs->fPictureCtx 63 may be used to provide user context to procs->fPictureProc; procs->fPictureProc 64 is called with a pointer to data, data byte length, and user context. 65 66 @param data container for serial data 67 @param procs custom serial data decoders; may be nullptr 68 @return SkPicture constructed from data 69 */ 70 static sk_sp<SkPicture> MakeFromData(const SkData* data, 71 const SkDeserialProcs* procs = nullptr); 72 73 /** 74 75 @param data pointer to serial data 76 @param size size of data 77 @param procs custom serial data decoders; may be nullptr 78 @return SkPicture constructed from data 79 */ 80 static sk_sp<SkPicture> MakeFromData(const void* data, size_t size, 81 const SkDeserialProcs* procs = nullptr); 82 83 /** \class SkPicture::AbortCallback 84 AbortCallback is an abstract class. An implementation of AbortCallback may 85 passed as a parameter to SkPicture::playback, to stop it before all drawing 86 commands have been processed. 87 88 If AbortCallback::abort returns true, SkPicture::playback is interrupted. 89 */ 90 class SK_API AbortCallback { 91 public: 92 93 /** Has no effect. 94 95 @return abstract class cannot be instantiated 96 */ AbortCallback()97 AbortCallback() {} 98 99 /** Has no effect. 100 */ ~AbortCallback()101 virtual ~AbortCallback() {} 102 103 /** Stops SkPicture playback when some condition is met. A subclass of 104 AbortCallback provides an override for abort() that can stop SkPicture::playback. 105 106 The part of SkPicture drawn when aborted is undefined. SkPicture instantiations are 107 free to stop drawing at different points during playback. 108 109 If the abort happens inside one or more calls to SkCanvas::save(), stack 110 of SkCanvas matrix and SkCanvas clip values is restored to its state before 111 SkPicture::playback was called. 112 113 @return true to stop playback 114 115 example: https://fiddle.skia.org/c/@Picture_AbortCallback_abort 116 */ 117 virtual bool abort() = 0; 118 }; 119 120 /** Replays the drawing commands on the specified canvas. In the case that the 121 commands are recorded, each command in the SkPicture is sent separately to canvas. 122 123 To add a single command to draw SkPicture to recording canvas, call 124 SkCanvas::drawPicture instead. 125 126 @param canvas receiver of drawing commands 127 @param callback allows interruption of playback 128 129 example: https://fiddle.skia.org/c/@Picture_playback 130 */ 131 virtual void playback(SkCanvas* canvas, AbortCallback* callback = nullptr) const = 0; 132 133 /** Returns cull SkRect for this picture, passed in when SkPicture was created. 134 Returned SkRect does not specify clipping SkRect for SkPicture; cull is hint 135 of SkPicture bounds. 136 137 SkPicture is free to discard recorded drawing commands that fall outside 138 cull. 139 140 @return bounds passed when SkPicture was created 141 142 example: https://fiddle.skia.org/c/@Picture_cullRect 143 */ 144 virtual SkRect cullRect() const = 0; 145 146 /** Returns a non-zero value unique among SkPicture in Skia process. 147 148 @return identifier for SkPicture 149 */ uniqueID()150 uint32_t uniqueID() const { return fUniqueID; } 151 152 /** Returns storage containing SkData describing SkPicture, using optional custom 153 encoders. 154 155 procs->fPictureProc permits supplying a custom function to encode SkPicture. 156 If procs->fPictureProc is nullptr, default encoding is used. procs->fPictureCtx 157 may be used to provide user context to procs->fPictureProc; procs->fPictureProc 158 is called with a pointer to SkPicture and user context. 159 160 @param procs custom serial data encoders; may be nullptr 161 @return storage containing serialized SkPicture 162 163 example: https://fiddle.skia.org/c/@Picture_serialize 164 */ 165 sk_sp<SkData> serialize(const SkSerialProcs* procs = nullptr) const; 166 167 /** Writes picture to stream, using optional custom encoders. 168 169 procs->fPictureProc permits supplying a custom function to encode SkPicture. 170 If procs->fPictureProc is nullptr, default encoding is used. procs->fPictureCtx 171 may be used to provide user context to procs->fPictureProc; procs->fPictureProc 172 is called with a pointer to SkPicture and user context. 173 174 @param stream writable serial data stream 175 @param procs custom serial data encoders; may be nullptr 176 177 example: https://fiddle.skia.org/c/@Picture_serialize_2 178 */ 179 void serialize(SkWStream* stream, const SkSerialProcs* procs = nullptr) const; 180 181 /** Returns a placeholder SkPicture. Result does not draw, and contains only 182 cull SkRect, a hint of its bounds. Result is immutable; it cannot be changed 183 later. Result identifier is unique. 184 185 Returned placeholder can be intercepted during playback to insert other 186 commands into SkCanvas draw stream. 187 188 @param cull placeholder dimensions 189 @return placeholder with unique identifier 190 191 example: https://fiddle.skia.org/c/@Picture_MakePlaceholder 192 */ 193 static sk_sp<SkPicture> MakePlaceholder(SkRect cull); 194 195 /** Returns the approximate number of operations in SkPicture. Returned value 196 may be greater or less than the number of SkCanvas calls 197 recorded: some calls may be recorded as more than one operation, other 198 calls may be optimized away. 199 200 @return approximate operation count 201 202 example: https://fiddle.skia.org/c/@Picture_approximateOpCount 203 */ 204 virtual int approximateOpCount() const = 0; 205 206 /** Returns the approximate byte size of SkPicture. Does not include large objects 207 referenced by SkPicture. 208 209 @return approximate size 210 211 example: https://fiddle.skia.org/c/@Picture_approximateBytesUsed 212 */ 213 virtual size_t approximateBytesUsed() const = 0; 214 215 /** Return a new shader that will draw with this picture. 216 * 217 * @param tmx The tiling mode to use when sampling in the x-direction. 218 * @param tmy The tiling mode to use when sampling in the y-direction. 219 * @param localMatrix Optional matrix used when sampling 220 * @param tile The tile rectangle in picture coordinates: this represents the subset 221 * (or superset) of the picture used when building a tile. It is not 222 * affected by localMatrix and does not imply scaling (only translation 223 * and cropping). If null, the tile rect is considered equal to the picture 224 * bounds. 225 * @return Returns a new shader object. Note: this function never returns null. 226 */ 227 sk_sp<SkShader> makeShader(SkTileMode tmx, SkTileMode tmy, 228 const SkMatrix* localMatrix, const SkRect* tileRect) const; 229 sk_sp<SkShader> makeShader(SkTileMode tmx, SkTileMode tmy, 230 const SkMatrix* localMatrix = nullptr) const; 231 232 private: 233 // Subclass whitelist. 234 SkPicture(); 235 friend class SkBigPicture; 236 friend class SkEmptyPicture; 237 friend class SkPicturePriv; 238 template <typename> friend class SkMiniPicture; 239 240 void serialize(SkWStream*, const SkSerialProcs*, class SkRefCntSet* typefaces, 241 bool textBlobsOnly=false) const; 242 static sk_sp<SkPicture> MakeFromStream(SkStream*, const SkDeserialProcs*, 243 class SkTypefacePlayback*); 244 friend class SkPictureData; 245 246 /** Return true if the SkStream/Buffer represents a serialized picture, and 247 fills out SkPictInfo. After this function returns, the data source is not 248 rewound so it will have to be manually reset before passing to 249 MakeFromStream or MakeFromBuffer. Note, MakeFromStream and 250 MakeFromBuffer perform this check internally so these entry points are 251 intended for stand alone tools. 252 If false is returned, SkPictInfo is unmodified. 253 */ 254 static bool StreamIsSKP(SkStream*, struct SkPictInfo*); 255 static bool BufferIsSKP(class SkReadBuffer*, struct SkPictInfo*); 256 friend bool SkPicture_StreamIsSKP(SkStream*, struct SkPictInfo*); 257 258 // Returns NULL if this is not an SkBigPicture. asSkBigPicture()259 virtual const class SkBigPicture* asSkBigPicture() const { return nullptr; } 260 261 friend struct SkPathCounter; 262 263 static bool IsValidPictInfo(const struct SkPictInfo& info); 264 static sk_sp<SkPicture> Forwardport(const struct SkPictInfo&, 265 const class SkPictureData*, 266 class SkReadBuffer* buffer); 267 268 struct SkPictInfo createHeader() const; 269 class SkPictureData* backport() const; 270 271 uint32_t fUniqueID; 272 }; 273 274 #endif 275