Picture records drawing commands made to Canvas. The command stream may be played in whole or in part at a later time.
Picture is an abstract class. Picture may be generated by Picture_Recorder or Drawable, or from Picture previously saved to Data or Stream.
Picture may contain any Canvas drawing command, as well as one or more Canvas_Matrix or Canvas_Clip. Picture has a cull Rect, which is used as a bounding box hint. To limit Picture bounds, use Canvas_Clip when recording or drawing Picture.
AbortCallback is an abstract class. An implementation of AbortCallback may passed as a parameter to SkPicture::playback, to stop it before all drawing commands have been processed.
If AbortCallback::abort returns true, SkPicture::playback is interrupted.
Has no effect.
abstract class cannot be instantiated
playback
Has no effect.
playback
Stops SkPicture playback when some condition is met. A subclass of AbortCallback provides an override for abort() that can stop SkPicture::playback.
The part of SkPicture drawn when aborted is undefined. SkPicture instantiations are free to stop drawing at different points during playback.
If the abort happens inside one or more calls to SkCanvas::save(), stack of SkCanvas matrix and SkCanvas clip values is restored to its state before SkPicture::playback was called.
true to stop playback
playback
Recreates SkPicture that was serialized into a stream. Returns constructed SkPicture if successful; otherwise, returns nullptr. Fails if data does not permit constructing valid SkPicture.
procs->fPictureProc permits supplying a custom function to decode SkPicture. If procs->fPictureProc is nullptr, default decoding is used. procs->fPictureCtx may be used to provide user context to procs->fPictureProc; procs->fPictureProc is called with a pointer to data, data byte length, and user context.
SkPicture constructed from stream data
MakeFromData SkPictureRecorder
Recreates SkPicture that was serialized into data. Returns constructed SkPicture if successful; otherwise, returns nullptr. Fails if data does not permit constructing valid SkPicture.
procs->fPictureProc permits supplying a custom function to decode SkPicture. If procs->fPictureProc is nullptr, default decoding is used. procs->fPictureCtx may be used to provide user context to procs->fPictureProc; procs->fPictureProc is called with a pointer to data, data byte length, and user context.
SkPicture constructed from data
MakeFromStream SkPictureRecorder
SkPicture constructed from data
MakeFromStream SkPictureRecorder
Replays the drawing commands on the specified canvas. In the case that the commands are recorded, each command in the SkPicture is sent separately to canvas.
To add a single command to draw SkPicture to recording canvas, call SkCanvas::drawPicture instead.
SkCanvas::drawPicture
Returns cull SkRect for this picture, passed in when SkPicture was created. Returned SkRect does not specify clipping SkRect for SkPicture; cull is hint of SkPicture bounds.
SkPicture is free to discard recorded drawing commands that fall outside cull.
bounds passed when SkPicture was created
SkCanvas::clipRect
Returns a non-zero value unique among SkPicture in Skia process.
identifier for SkPicture
empty picture id = 1 placeholder id = 2
SkRefCnt
Returns storage containing SkData describing SkPicture, using optional custom encoders.
procs->fPictureProc permits supplying a custom function to encode SkPicture. If procs->fPictureProc is nullptr, default encoding is used. procs->fPictureCtx may be used to provide user context to procs->fPictureProc; procs->fPictureProc is called with a pointer to SkPicture and user context.
storage containing serialized SkPicture
MakeFromData SkData SkSerialProcs
Writes picture to stream, using optional custom encoders.
procs->fPictureProc permits supplying a custom function to encode SkPicture. If procs->fPictureProc is nullptr, default encoding is used. procs->fPictureCtx may be used to provide user context to procs->fPictureProc; procs->fPictureProc is called with a pointer to SkPicture and user context.
MakeFromStream SkWStream SkSerialProcs
Returns a placeholder SkPicture. Result does not draw, and contains only cull SkRect, a hint of its bounds. Result is immutable; it cannot be changed later. Result identifier is unique.
Returned placeholder can be intercepted during playback to insert other commands into SkCanvas draw stream.
placeholder with unique identifier
MakeFromStream MakeFromData uniqueID
Returns the approximate number of operations in SkPicture. Returned value may be greater or less than the number of SkCanvas calls recorded: some calls may be recorded as more than one operation, other calls may be optimized away.
approximate operation count
approximateBytesUsed
Returns the approximate byte size of SkPicture. Does not include large objects referenced by SkPicture.
approximate size
approximateOpCount