SkPicture Class Reference

#include <SkPicture.h>

Inheritance diagram for SkPicture:

Classes
class	AbortCallback

Public Member Functions
	~SkPicture () override
virtual void	playback (SkCanvas *canvas, AbortCallback *callback=nullptr) const =0
virtual SkRect	cullRect () const =0
uint32_t	uniqueID () const
sk_sp< SkData >	serialize (const SkSerialProcs *procs=nullptr) const
void	serialize (SkWStream *stream, const SkSerialProcs *procs=nullptr) const
virtual int	approximateOpCount (bool nested=false) const =0
virtual size_t	approximateBytesUsed () const =0
sk_sp< SkShader >	makeShader (SkTileMode tmx, SkTileMode tmy, SkFilterMode mode, const SkMatrix *localMatrix, const SkRect *tileRect) const
sk_sp< SkShader >	makeShader (SkTileMode tmx, SkTileMode tmy, SkFilterMode mode) const
Public Member Functions inherited from SkRefCntBase
	SkRefCntBase ()
virtual	~SkRefCntBase ()
bool	unique () const
void	ref () const
void	unref () const

Static Public Member Functions
static sk_sp< SkPicture >	MakeFromStream (SkStream *stream, const SkDeserialProcs *procs=nullptr)
static sk_sp< SkPicture >	MakeFromData (const SkData *data, const SkDeserialProcs *procs=nullptr)
static sk_sp< SkPicture >	MakeFromData (const void *data, size_t size, const SkDeserialProcs *procs=nullptr)
static sk_sp< SkPicture >	MakePlaceholder (SkRect cull)

Private Member Functions
virtual const class SkBigPicture *	asSkBigPicture () const

Friends
class	SkBigPicture
class	SkEmptyPicture
class	SkPicturePriv
class	SkPictureData
bool	SkPicture_StreamIsSKP (SkStream *, struct SkPictInfo *)

Detailed Description

SkPicture records drawing commands made to SkCanvas. The command stream may be played in whole or in part at a later time.

SkPicture is an abstract class. SkPicture may be generated by SkPictureRecorder or SkDrawable, or from SkPicture previously saved to SkData or SkStream.

SkPicture may contain any SkCanvas drawing command, as well as one or more SkCanvas matrix or SkCanvas clip. SkPicture has a cull SkRect, which is used as a bounding box hint. To limit SkPicture bounds, use SkCanvas clip when recording or drawing SkPicture.

Definition at line 44 of file SkPicture.h.

Constructor & Destructor Documentation

~SkPicture()

SkPicture::~SkPicture ( )

override

Definition at line 52 of file SkPicture.cpp.

                      {
    if (fAddedToCache.load()) {
        SkResourceCache::PostPurgeSharedID(SkPicturePriv::MakeSharedID(fUniqueID));
    }
}

Member Function Documentation

approximateBytesUsed()

virtual size_t SkPicture::approximateBytesUsed ( ) const

pure virtual

Returns the approximate byte size of SkPicture. Does not include large objects referenced by SkPicture.

Returns

approximate size

example: https://fiddle.skia.org/c/@Picture_approximateBytesUsed

Implemented in SkBigPicture, and SkEmptyPicture.

approximateOpCount()

virtual int SkPicture::approximateOpCount ( bool  nested = false ) const

pure virtual

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.

Parameters

nested

if true, include the op-counts of nested pictures as well, else just return count the ops in the top-level picture.

Returns

approximate operation count

example: https://fiddle.skia.org/c/@Picture_approximateOpCount

Implemented in SkBigPicture, and SkEmptyPicture.

asSkBigPicture()

virtual const class SkBigPicture * SkPicture::asSkBigPicture ( ) const

inlineprivatevirtual

Reimplemented in SkBigPicture.

Definition at line 277 of file SkPicture.h.

{ return nullptr; }

cullRect()

virtual SkRect SkPicture::cullRect ( ) const

pure virtual

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.

Returns

bounds passed when SkPicture was created

example: https://fiddle.skia.org/c/@Picture_cullRect

Implemented in SkBigPicture, and SkEmptyPicture.

MakeFromData() [1/2]

sk_sp< SkPicture > SkPicture::MakeFromData ( const SkData *  data, const SkDeserialProcs *  procs = nullptr  )

static

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.

Parameters

data	container for serial data
procs	custom serial data decoders; may be nullptr

Returns

SkPicture constructed from data

Definition at line 160 of file SkPicture.cpp.

                                                                                         {
    if (!data) {
        return nullptr;
    }
    SkMemoryStream stream(data->data(), data->size());
    return MakeFromStreamPriv(&stream, procs, nullptr, kNestedSKPLimit);
}

MakeFromData() [2/2]

sk_sp< SkPicture > SkPicture::MakeFromData ( const void *  data, size_t  size, const SkDeserialProcs *  procs = nullptr  )

static

Parameters

data	pointer to serial data
size	size of data
procs	custom serial data decoders; may be nullptr

Returns

SkPicture constructed from data

Definition at line 151 of file SkPicture.cpp.

                                                                       {
    if (!data) {
        return nullptr;
    }
    SkMemoryStream stream(data, size);
    return MakeFromStreamPriv(&stream, procs, nullptr, kNestedSKPLimit);
}

MakeFromStream()

sk_sp< SkPicture > SkPicture::MakeFromStream ( SkStream *  stream, const SkDeserialProcs *  procs = nullptr  )

static

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.

Parameters

stream	container for serial data
procs	custom serial data decoders; may be nullptr

Returns

SkPicture constructed from stream data

Definition at line 147 of file SkPicture.cpp.

                                                                                         {
    return MakeFromStreamPriv(stream, procs, nullptr, kNestedSKPLimit);
}

MakePlaceholder()

sk_sp< SkPicture > SkPicture::MakePlaceholder ( SkRect  cull )

static

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.

Parameters

cull	placeholder dimensions

Returns

placeholder with unique identifier

example: https://fiddle.skia.org/c/@Picture_MakePlaceholder

Definition at line 337 of file SkPicture.cpp.

                                                       {
    struct Placeholder : public SkPicture {
          explicit Placeholder(SkRect cull) : fCull(cull) {}
 
          void playback(SkCanvas*, AbortCallback*) const override { }
 
          // approximateOpCount() needs to be greater than kMaxPictureOpsToUnrollInsteadOfRef
          // (SkCanvasPriv.h) to avoid unrolling this into a parent picture.
          int approximateOpCount(bool) const override {
              return kMaxPictureOpsToUnrollInsteadOfRef+1;
          }
          size_t approximateBytesUsed() const override { return sizeof(*this); }
          SkRect cullRect()             const override { return fCull; }
 
          SkRect fCull;
    };
    return sk_make_sp<Placeholder>(cull);
}

makeShader() [1/2]

sk_sp< SkShader > SkPicture::makeShader ( SkTileMode  tmx, SkTileMode  tmy, SkFilterMode  mode  ) const

inline

Definition at line 246 of file SkPicture.h.

                                                                                        {
        return this->makeShader(tmx, tmy, mode, nullptr, nullptr);
    }

makeShader() [2/2]

sk_sp< SkShader > SkPicture::makeShader	(	SkTileMode	tmx,
		SkTileMode	tmy,
		SkFilterMode	mode,
		const SkMatrix *	localMatrix,
		const SkRect *	tileRect
	)		const

Return a new shader that will draw with this picture.

Parameters

tmx	The tiling mode to use when sampling in the x-direction.
tmy	The tiling mode to use when sampling in the y-direction.
mode	How to filter the tiles
localMatrix	Optional matrix used when sampling
tileRect	The tile rectangle in picture coordinates: this represents the subset (or superset) of the picture used when building a tile. It is not affected by localMatrix and does not imply scaling (only translation and cropping). If null, the tile rect is considered equal to the picture bounds.

Returns

Returns a new shader object. Note: this function never returns null.

Definition at line 39 of file SkPictureShader.cpp.

                                                                                             {
    if (localMatrix && !localMatrix->invert(nullptr)) {
        return nullptr;
    }
    return SkPictureShader::Make(sk_ref_sp(this), tmx, tmy, filter, localMatrix, tile);
}

playback()

virtual void SkPicture::playback ( SkCanvas *  canvas, AbortCallback *  callback = nullptr  ) const

pure virtual

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.

Parameters

canvas	receiver of drawing commands
callback	allows interruption of playback

example: https://fiddle.skia.org/c/@Picture_playback

Implemented in SkBigPicture, and SkEmptyPicture.

serialize() [1/2]

sk_sp< SkData > SkPicture::serialize

(

const SkSerialProcs *

procs = nullptr

)

const

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.

The default behavior for serializing SkImages is to encode a nullptr. Should clients want to, for example, encode these SkImages as PNGs so they can be deserialized, they must provide SkSerialProcs with the fImageProc set to do so.

Parameters

procs

custom serial data encoders; may be nullptr

Returns

storage containing serialized SkPicture

example: https://fiddle.skia.org/c/@Picture_serialize

Definition at line 249 of file SkPicture.cpp.

                                                                   {
    SkDynamicMemoryWStream stream;
    this->serialize(&stream, procs, nullptr);
    return stream.detachAsData();
}

serialize() [2/2]

void SkPicture::serialize	(	SkWStream *	stream,
		const SkSerialProcs *	procs = nullptr
	)		const

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.

The default behavior for serializing SkImages is to encode a nullptr. Should clients want to, for example, encode these SkImages as PNGs so they can be deserialized, they must provide SkSerialProcs with the fImageProc set to do so.

Parameters

stream	writable serial data stream
procs	custom serial data encoders; may be nullptr

example: https://fiddle.skia.org/c/@Picture_serialize_2

Definition at line 245 of file SkPicture.cpp.

                                                                             {
    this->serialize(stream, procs, nullptr);
}

uniqueID()

uint32_t SkPicture::uniqueID ( ) const

inline

Returns a non-zero value unique among SkPicture in Skia process.

Returns

identifier for SkPicture

Definition at line 155 of file SkPicture.h.

{ return fUniqueID; }

Friends And Related Symbol Documentation

SkBigPicture

friend class SkBigPicture

friend

Definition at line 253 of file SkPicture.h.

SkEmptyPicture

friend class SkEmptyPicture

friend

Definition at line 254 of file SkPicture.h.

SkPicture_StreamIsSKP

bool SkPicture_StreamIsSKP ( SkStream *  , struct SkPictInfo *    )

friend

Definition at line 109 of file SkPicture.cpp.

                                                                {
    return SkPicture::StreamIsSKP(stream, pInfo);
}

SkPictureData

friend class SkPictureData

friend

Definition at line 262 of file SkPicture.h.

SkPicturePriv

friend class SkPicturePriv

friend

Definition at line 255 of file SkPicture.h.

---

The documentation for this class was generated from the following files:

• third_party/skia/include/core/SkPicture.h
• third_party/skia/src/core/SkPicture.cpp
• third_party/skia/src/shaders/SkPictureShader.cpp