A Canvas encapsulates all of the state about drawing into a device (bitmap). More...

#include <SkCanvas.h>

Inheritance diagram for SkCanvas:

Classes
class	AutoValidateClip

struct	Lattice
	Specifies coordinates to divide a bitmap into (xCount*yCount) rects. More...

class	LayerIter
	After calling saveLayer(), there can be any number of devices that make up the top-most drawing area. More...

struct	SaveLayerRec

Public Types
enum	{ kIsOpaque_SaveLayerFlag = 1 << 0, kPreserveLCDText_SaveLayerFlag = 1 << 1 }

enum	PointMode { kPoints_PointMode, kLines_PointMode, kPolygon_PointMode }

enum	SrcRectConstraint { kStrict_SrcRectConstraint, kFast_SrcRectConstraint }
	Controls the behavior at the edge of the src-rect, when specified in drawImageRect, trading off speed for exactness. More...

enum	VertexMode { kTriangles_VertexMode, kTriangleStrip_VertexMode, kTriangleFan_VertexMode }

typedef uint32_t	SaveLayerFlags

typedef SkCanvasClipVisitor	ClipVisitor

Public Member Functions
	SkCanvas ()
	Creates an empty canvas with no backing device/pixels, and zero dimensions.

	SkCanvas (int width, int height, const SkSurfaceProps *=NULL)
	Creates a canvas of the specified dimensions, but explicitly not backed by any device/pixels. More...

	SkCanvas (SkBaseDevice *device)
	Construct a canvas with the specified device to draw into. More...

	SkCanvas (const SkBitmap &bitmap)
	Construct a canvas with the specified bitmap to draw into. More...

	SkCanvas (const SkBitmap &bitmap, const SkSurfaceProps &props)
	Construct a canvas with the specified bitmap to draw into. More...

SkMetaData &	getMetaData ()

SkImageInfo	imageInfo () const
	Return ImageInfo for this canvas. More...

bool	getProps (SkSurfaceProps *) const
	If the canvas is backed by pixels (cpu or gpu), this writes a copy of the SurfaceProps for the canvas to the location supplied by the caller, and returns true. More...

void	flush ()
	Trigger the immediate execution of all pending draw operations. More...

virtual SkISize	getBaseLayerSize () const
	Gets the size of the base or root layer in global canvas coordinates. More...

SkISize	getDeviceSize () const
	DEPRECATED: call getBaseLayerSize.

SkBaseDevice *	getDevice_just_for_deprecated_compatibility_testing () const

sk_sp< SkSurface >	makeSurface (const SkImageInfo &, const SkSurfaceProps *=nullptr)
	Create a new surface matching the specified info, one that attempts to be maximally compatible when used with this canvas. More...

GrContext *	getGrContext ()
	Return the GPU context of the device that is associated with the canvas. More...

void *	accessTopLayerPixels (SkImageInfo info, size_t rowBytes, SkIPoint *origin=NULL)
	If the canvas has writable pixels in its top layer (and is not recording to a picture or other non-raster target) and has direct access to its pixels (i.e. More...

bool	peekPixels (SkPixmap *)
	If the canvas has readable pixels in its base layer (and is not recording to a picture or other non-raster target) and has direct access to its pixels (i.e. More...

bool	readPixels (const SkImageInfo &dstInfo, void *dstPixels, size_t dstRowBytes, int srcX, int srcY)
	Copy the pixels from the base-layer into the specified buffer (pixels + rowBytes), converting them into the requested format (SkImageInfo). More...

bool	readPixels (SkBitmap *bitmap, int srcX, int srcY)
	Helper for calling readPixels(info, ...). More...

bool	readPixels (const SkIRect &srcRect, SkBitmap *bitmap)
	Helper for allocating pixels and then calling readPixels(info, ...). More...

bool	writePixels (const SkImageInfo &, const void *pixels, size_t rowBytes, int x, int y)
	This method affects the pixels in the base-layer, and operates in pixel coordinates, ignoring the matrix and clip. More...

bool	writePixels (const SkBitmap &bitmap, int x, int y)
	Helper for calling writePixels(info, ...) by passing its pixels and rowbytes. More...

int	save ()
	This call saves the current matrix, clip, and drawFilter, and pushes a copy onto a private stack. More...

int	saveLayer (const SkRect bounds, const SkPaint paint)
	This behaves the same as save(), but in addition it allocates an offscreen bitmap. More...

int	saveLayer (const SkRect &bounds, const SkPaint *paint)

int	saveLayerPreserveLCDTextRequests (const SkRect bounds, const SkPaint paint)
	Temporary name. More...

int	saveLayerAlpha (const SkRect *bounds, U8CPU alpha)
	This behaves the same as save(), but in addition it allocates an offscreen bitmap. More...

int	saveLayer (const SaveLayerRec &)

void	restore ()
	This call balances a previous call to save(), and is used to remove all modifications to the matrix/clip/drawFilter state since the last save call. More...

int	getSaveCount () const
	Returns the number of matrix/clip states on the SkCanvas' private stack. More...

void	restoreToCount (int saveCount)
	Efficient way to pop any calls to save() that happened after the save count reached saveCount. More...

void	translate (SkScalar dx, SkScalar dy)
	Preconcat the current matrix with the specified translation. More...

void	scale (SkScalar sx, SkScalar sy)
	Preconcat the current matrix with the specified scale. More...

void	rotate (SkScalar degrees)
	Preconcat the current matrix with the specified rotation about the origin. More...

void	rotate (SkScalar degrees, SkScalar px, SkScalar py)
	Preconcat the current matrix with the specified rotation about a given point. More...

void	skew (SkScalar sx, SkScalar sy)
	Preconcat the current matrix with the specified skew. More...

void	concat (const SkMatrix &matrix)
	Preconcat the current matrix with the specified matrix. More...

void	setMatrix (const SkMatrix &matrix)
	Replace the current matrix with a copy of the specified matrix. More...

void	resetMatrix ()
	Helper for setMatrix(identity). More...

void	clipRect (const SkRect &rect, SkRegion::Op op=SkRegion::kIntersect_Op, bool doAntiAlias=false)
	Modify the current clip with the specified rectangle. More...

void	clipRRect (const SkRRect &rrect, SkRegion::Op op=SkRegion::kIntersect_Op, bool doAntiAlias=false)
	Modify the current clip with the specified SkRRect. More...

void	clipPath (const SkPath &path, SkRegion::Op op=SkRegion::kIntersect_Op, bool doAntiAlias=false)
	Modify the current clip with the specified path. More...

void	setAllowSoftClip (bool allow)
	EXPERIMENTAL – only used for testing Set to false to force clips to be hard, even if doAntiAlias=true is passed to clipRect or clipPath.

void	setAllowSimplifyClip (bool allow)
	EXPERIMENTAL – only used for testing Set to simplify clip stack using path ops.

void	clipRegion (const SkRegion &deviceRgn, SkRegion::Op op=SkRegion::kIntersect_Op)
	Modify the current clip with the specified region. More...

void	setClipRegion (const SkRegion &deviceRgn)
	Helper for clipRegion(rgn, kReplace_Op). More...

bool	quickReject (const SkRect &rect) const
	Return true if the specified rectangle, after being transformed by the current matrix, would lie completely outside of the current clip. More...

bool	quickReject (const SkPath &path) const
	Return true if the specified path, after being transformed by the current matrix, would lie completely outside of the current clip. More...

virtual bool	getClipBounds (SkRect *bounds) const
	Return the bounds of the current clip (in local coordinates) in the bounds parameter, and return true if it is non-empty. More...

virtual bool	getClipDeviceBounds (SkIRect *bounds) const
	Return the bounds of the current clip, in device coordinates; returns true if non-empty. More...

void	drawARGB (U8CPU a, U8CPU r, U8CPU g, U8CPU b, SkXfermode::Mode mode=SkXfermode::kSrcOver_Mode)
	Fill the entire canvas' bitmap (restricted to the current clip) with the specified ARGB color, using the specified mode. More...

void	drawColor (SkColor color, SkXfermode::Mode mode=SkXfermode::kSrcOver_Mode)
	Fill the entire canvas' bitmap (restricted to the current clip) with the specified color and mode. More...

void	clear (SkColor color)
	Helper method for drawing a color in SRC mode, completely replacing all the pixels in the current clip with this color.

void	discard ()
	This makes the contents of the canvas undefined. More...

void	drawPaint (const SkPaint &paint)
	Fill the entire canvas (restricted to the current clip) with the specified paint. More...

void	drawPoints (PointMode mode, size_t count, const SkPoint pts[], const SkPaint &paint)
	Draw a series of points, interpreted based on the PointMode mode. More...

void	drawPoint (SkScalar x, SkScalar y, const SkPaint &paint)
	Helper method for drawing a single point. More...

void	drawPoint (SkScalar x, SkScalar y, SkColor color)
	Draws a single pixel in the specified color. More...

void	drawLine (SkScalar x0, SkScalar y0, SkScalar x1, SkScalar y1, const SkPaint &paint)
	Draw a line segment with the specified start and stop x,y coordinates, using the specified paint. More...

void	drawRect (const SkRect &rect, const SkPaint &paint)
	Draw the specified rectangle using the specified paint. More...

void	drawIRect (const SkIRect &rect, const SkPaint &paint)
	Draw the specified rectangle using the specified paint. More...

void	drawRectCoords (SkScalar left, SkScalar top, SkScalar right, SkScalar bottom, const SkPaint &paint)
	Draw the specified rectangle using the specified paint. More...

void	drawOval (const SkRect &oval, const SkPaint &)
	Draw the specified oval using the specified paint. More...

void	drawRRect (const SkRRect &rrect, const SkPaint &paint)
	Draw the specified RRect using the specified paint The rrect will be filled or stroked based on the Style in the paint. More...

void	drawDRRect (const SkRRect &outer, const SkRRect &inner, const SkPaint &)
	Draw the annulus formed by the outer and inner rrects. More...

void	drawCircle (SkScalar cx, SkScalar cy, SkScalar radius, const SkPaint &paint)
	Draw the specified circle using the specified paint. More...

void	drawArc (const SkRect &oval, SkScalar startAngle, SkScalar sweepAngle, bool useCenter, const SkPaint &paint)
	Draw the specified arc, which will be scaled to fit inside the specified oval. More...

void	drawRoundRect (const SkRect &rect, SkScalar rx, SkScalar ry, const SkPaint &paint)
	Draw the specified round-rect using the specified paint. More...

void	drawPath (const SkPath &path, const SkPaint &paint)
	Draw the specified path using the specified paint. More...

void	drawImage (const SkImage image, SkScalar left, SkScalar top, const SkPaint paint=NULL)
	Draw the specified image, with its top/left corner at (x,y), using the specified paint, transformed by the current matrix. More...

void	drawImage (const sk_sp< SkImage > &image, SkScalar left, SkScalar top, const SkPaint *paint=NULL)

void	drawImageRect (const SkImage image, const SkRect &src, const SkRect &dst, const SkPaint paint, SrcRectConstraint constraint=kStrict_SrcRectConstraint)
	Draw the specified image, scaling and translating so that it fills the specified dst rect. More...

void	drawImageRect (const SkImage image, const SkIRect &isrc, const SkRect &dst, const SkPaint paint, SrcRectConstraint=kStrict_SrcRectConstraint)

void	drawImageRect (const SkImage image, const SkRect &dst, const SkPaint paint, SrcRectConstraint=kStrict_SrcRectConstraint)

void	drawImageRect (const sk_sp< SkImage > &image, const SkRect &src, const SkRect &dst, const SkPaint *paint, SrcRectConstraint constraint=kStrict_SrcRectConstraint)

void	drawImageRect (const sk_sp< SkImage > &image, const SkIRect &isrc, const SkRect &dst, const SkPaint *paint, SrcRectConstraint cons=kStrict_SrcRectConstraint)

void	drawImageRect (const sk_sp< SkImage > &image, const SkRect &dst, const SkPaint *paint, SrcRectConstraint cons=kStrict_SrcRectConstraint)

void	drawImageNine (const SkImage , const SkIRect &center, const SkRect &dst, const SkPaint paint=nullptr)
	Draw the image stretched differentially to fit into dst. More...

void	drawImageNine (const sk_sp< SkImage > &image, const SkIRect &center, const SkRect &dst, const SkPaint *paint=nullptr)

void	drawBitmap (const SkBitmap &bitmap, SkScalar left, SkScalar top, const SkPaint *paint=NULL)
	Draw the specified bitmap, with its top/left corner at (x,y), using the specified paint, transformed by the current matrix. More...

void	drawBitmapRect (const SkBitmap &bitmap, const SkRect &src, const SkRect &dst, const SkPaint *paint, SrcRectConstraint=kStrict_SrcRectConstraint)
	Draw the specified bitmap, scaling and translating so that it fills the specified dst rect. More...

void	drawBitmapRect (const SkBitmap &bitmap, const SkIRect &isrc, const SkRect &dst, const SkPaint *paint, SrcRectConstraint=kStrict_SrcRectConstraint)

void	drawBitmapRect (const SkBitmap &bitmap, const SkRect &dst, const SkPaint *paint, SrcRectConstraint=kStrict_SrcRectConstraint)

void	drawBitmapNine (const SkBitmap &bitmap, const SkIRect &center, const SkRect &dst, const SkPaint *paint=NULL)
	Draw the bitmap stretched or shrunk differentially to fit into dst. More...

void	drawBitmapLattice (const SkBitmap &bitmap, const Lattice &lattice, const SkRect &dst, const SkPaint *paint=nullptr)
	Draw the bitmap stretched or shrunk differentially to fit into dst. More...

void	drawImageLattice (const SkImage image, const Lattice &lattice, const SkRect &dst, const SkPaint paint=nullptr)

void	drawText (const void *text, size_t byteLength, SkScalar x, SkScalar y, const SkPaint &paint)
	Draw the text, with origin at (x,y), using the specified paint. More...

void	drawPosText (const void *text, size_t byteLength, const SkPoint pos[], const SkPaint &paint)
	Draw the text, with each character/glyph origin specified by the pos[] array. More...

void	drawPosTextH (const void *text, size_t byteLength, const SkScalar xpos[], SkScalar constY, const SkPaint &paint)
	Draw the text, with each character/glyph origin specified by the x coordinate taken from the xpos[] array, and the y from the constY param. More...

void	drawTextOnPathHV (const void *text, size_t byteLength, const SkPath &path, SkScalar hOffset, SkScalar vOffset, const SkPaint &paint)
	Draw the text, with origin at (x,y), using the specified paint, along the specified path. More...

void	drawTextOnPath (const void text, size_t byteLength, const SkPath &path, const SkMatrix matrix, const SkPaint &paint)
	Draw the text, with origin at (x,y), using the specified paint, along the specified path. More...

void	drawTextRSXform (const void text, size_t byteLength, const SkRSXform[], const SkRect cullRect, const SkPaint &paint)
	Draw the text with each character/glyph individually transformed by its xform. More...

void	drawTextBlob (const SkTextBlob *blob, SkScalar x, SkScalar y, const SkPaint &paint)
	Draw the text blob, offset by (x,y), using the specified paint. More...

void	drawTextBlob (const sk_sp< SkTextBlob > &blob, SkScalar x, SkScalar y, const SkPaint &paint)

void	drawPicture (const SkPicture *picture)
	Draw the picture into this canvas. More...

void	drawPicture (const sk_sp< SkPicture > &picture)

void	drawPicture (const SkPicture , const SkMatrix matrix, const SkPaint *paint)
	Draw the picture into this canvas. More...

void	drawPicture (const sk_sp< SkPicture > &picture, const SkMatrix matrix, const SkPaint paint)

void	drawVertices (VertexMode vmode, int vertexCount, const SkPoint vertices[], const SkPoint texs[], const SkColor colors[], SkXfermode *xmode, const uint16_t indices[], int indexCount, const SkPaint &paint)
	Draw the array of vertices, interpreted as triangles (based on mode). More...

void	drawVertices (VertexMode vmode, int vertexCount, const SkPoint vertices[], const SkPoint texs[], const SkColor colors[], const sk_sp< SkXfermode > &xmode, const uint16_t indices[], int indexCount, const SkPaint &paint)

void	drawPatch (const SkPoint cubics[12], const SkColor colors[4], const SkPoint texCoords[4], SkXfermode *xmode, const SkPaint &paint)
	Draw a cubic coons patch. More...

void	drawPatch (const SkPoint cubics[12], const SkColor colors[4], const SkPoint texCoords[4], const sk_sp< SkXfermode > &xmode, const SkPaint &paint)

void	drawAtlas (const SkImage atlas, const SkRSXform xform[], const SkRect tex[], const SkColor colors[], int count, SkXfermode::Mode, const SkRect cullRect, const SkPaint *paint)
	Draw a set of sprites from the atlas. More...

void	drawAtlas (const SkImage atlas, const SkRSXform xform[], const SkRect tex[], int count, const SkRect cullRect, const SkPaint *paint)

void	drawAtlas (const sk_sp< SkImage > &atlas, const SkRSXform xform[], const SkRect tex[], const SkColor colors[], int count, SkXfermode::Mode mode, const SkRect cull, const SkPaint paint)

void	drawAtlas (const sk_sp< SkImage > &atlas, const SkRSXform xform[], const SkRect tex[], int count, const SkRect cullRect, const SkPaint paint)

void	drawDrawable (SkDrawable drawable, const SkMatrix =NULL)
	Draw the contents of this drawable into the canvas. More...

void	drawDrawable (SkDrawable *, SkScalar x, SkScalar y)

void	drawAnnotation (const SkRect &, const char key[], SkData *value)
	Send an "annotation" to the canvas. More...

void	drawAnnotation (const SkRect &rect, const char key[], const sk_sp< SkData > &value)

virtual bool	isClipEmpty () const
	Return true if the current clip is empty (i.e. More...

virtual bool	isClipRect () const
	Returns true if the current clip is just a (non-empty) rectangle. More...

const SkMatrix &	getTotalMatrix () const
	Return the current matrix on the canvas. More...

const SkClipStack *	getClipStack () const
	Return the clip stack. More...

void	replayClips (ClipVisitor *) const
	Replays the clip operations, back to front, that have been applied to the canvas, calling the appropriate method on the visitor for each clip. More...

GrDrawContext *	internal_private_accessTopLayerDrawContext ()

void	legacy_drawImageRect (const SkImage image, const SkRect src, const SkRect &dst, const SkPaint *paint, SrcRectConstraint constraint=kStrict_SrcRectConstraint)

void	legacy_drawBitmapRect (const SkBitmap &bitmap, const SkRect src, const SkRect &dst, const SkPaint paint, SrcRectConstraint constraint=kStrict_SrcRectConstraint)

void	temporary_internal_describeTopLayer (SkMatrix matrix, SkIRect clip_bounds)
	Returns CTM and clip bounds, translated from canvas coordinates to top layer coordinates.

Public Member Functions inherited from SkRefCntBase
	SkRefCntBase ()
	Default construct, initializing the reference count to 1.

virtual	~SkRefCntBase ()
	Destruct, asserting that the reference count is 1.

int32_t	getRefCnt () const
	Return the reference count. More...

void	validate () const

bool	unique () const
	May return true if the caller is the only owner. More...

void	ref () const
	Increment the reference count. More...

void	unref () const
	Decrement the reference count. More...

Static Public Member Functions
static SkCanvas *	NewRasterDirect (const SkImageInfo &, void *, size_t)
	Attempt to allocate raster canvas, matching the ImageInfo, that will draw directly into the specified pixels. More...

static SkCanvas *	NewRasterDirectN32 (int width, int height, SkPMColor *pixels, size_t rowBytes)

static void	Internal_Private_SetIgnoreSaveLayerBounds (bool)

static bool	Internal_Private_GetIgnoreSaveLayerBounds ()

static void	Internal_Private_SetTreatSpriteAsBitmap (bool)

static bool	Internal_Private_GetTreatSpriteAsBitmap ()

Protected Types
enum	SaveLayerStrategy { kFullLayer_SaveLayerStrategy, kNoLayer_SaveLayerStrategy }

enum	ClipEdgeStyle { kHard_ClipEdgeStyle, kSoft_ClipEdgeStyle }

Protected Member Functions
SkBaseDevice *	getDevice () const
	DEPRECATED. More...

virtual sk_sp< SkSurface >	onNewSurface (const SkImageInfo &, const SkSurfaceProps &)

virtual bool	onPeekPixels (SkPixmap *)

virtual bool	onAccessTopLayerPixels (SkPixmap *)

virtual SkImageInfo	onImageInfo () const

virtual bool	onGetProps (SkSurfaceProps *) const

virtual void	onFlush ()

virtual void	willSave ()

virtual SaveLayerStrategy	getSaveLayerStrategy (const SaveLayerRec &)

virtual void	willRestore ()

virtual void	didRestore ()

virtual void	didConcat (const SkMatrix &)

virtual void	didSetMatrix (const SkMatrix &)

virtual void	didTranslate (SkScalar dx, SkScalar dy)

virtual void	onDrawAnnotation (const SkRect &, const char key[], SkData *value)

virtual void	onDrawDRRect (const SkRRect &, const SkRRect &, const SkPaint &)

virtual void	onDrawText (const void *text, size_t byteLength, SkScalar x, SkScalar y, const SkPaint &paint)

virtual void	onDrawPosText (const void *text, size_t byteLength, const SkPoint pos[], const SkPaint &paint)

virtual void	onDrawPosTextH (const void *text, size_t byteLength, const SkScalar xpos[], SkScalar constY, const SkPaint &paint)

virtual void	onDrawTextOnPath (const void text, size_t byteLength, const SkPath &path, const SkMatrix matrix, const SkPaint &paint)

virtual void	onDrawTextRSXform (const void text, size_t byteLength, const SkRSXform[], const SkRect cullRect, const SkPaint &paint)

virtual void	onDrawTextBlob (const SkTextBlob *blob, SkScalar x, SkScalar y, const SkPaint &paint)

virtual void	onDrawPatch (const SkPoint cubics[12], const SkColor colors[4], const SkPoint texCoords[4], SkXfermode *xmode, const SkPaint &paint)

virtual void	onDrawDrawable (SkDrawable , const SkMatrix )

virtual void	onDrawPaint (const SkPaint &)

virtual void	onDrawRect (const SkRect &, const SkPaint &)

virtual void	onDrawOval (const SkRect &, const SkPaint &)

virtual void	onDrawArc (const SkRect &, SkScalar startAngle, SkScalar sweepAngle, bool useCenter, const SkPaint &)

virtual void	onDrawRRect (const SkRRect &, const SkPaint &)

virtual void	onDrawPoints (PointMode, size_t count, const SkPoint pts[], const SkPaint &)

virtual void	onDrawVertices (VertexMode, int vertexCount, const SkPoint vertices[], const SkPoint texs[], const SkColor colors[], SkXfermode *, const uint16_t indices[], int indexCount, const SkPaint &)

virtual void	onDrawAtlas (const SkImage , const SkRSXform[], const SkRect[], const SkColor[], int count, SkXfermode::Mode, const SkRect cull, const SkPaint *)

virtual void	onDrawPath (const SkPath &, const SkPaint &)

virtual void	onDrawImage (const SkImage , SkScalar dx, SkScalar dy, const SkPaint )

virtual void	onDrawImageRect (const SkImage , const SkRect , const SkRect &, const SkPaint *, SrcRectConstraint)

virtual void	onDrawImageNine (const SkImage , const SkIRect &center, const SkRect &dst, const SkPaint )

virtual void	onDrawImageLattice (const SkImage , const Lattice &lattice, const SkRect &dst, const SkPaint )

virtual void	onDrawBitmap (const SkBitmap &, SkScalar dx, SkScalar dy, const SkPaint *)

virtual void	onDrawBitmapRect (const SkBitmap &, const SkRect , const SkRect &, const SkPaint , SrcRectConstraint)

virtual void	onDrawBitmapNine (const SkBitmap &, const SkIRect &center, const SkRect &dst, const SkPaint *)

virtual void	onDrawBitmapLattice (const SkBitmap &, const Lattice &lattice, const SkRect &dst, const SkPaint *)

virtual void	onClipRect (const SkRect &rect, SkRegion::Op op, ClipEdgeStyle edgeStyle)

virtual void	onClipRRect (const SkRRect &rrect, SkRegion::Op op, ClipEdgeStyle edgeStyle)

virtual void	onClipPath (const SkPath &path, SkRegion::Op op, ClipEdgeStyle edgeStyle)

virtual void	onClipRegion (const SkRegion &deviceRgn, SkRegion::Op op)

virtual void	onDiscard ()

virtual void	onDrawPicture (const SkPicture , const SkMatrix , const SkPaint *)

virtual SkCanvas *	canvasForDrawIter ()

bool	clipRectBounds (const SkRect bounds, SaveLayerFlags, SkIRect intersection, const SkImageFilter *imageFilter=NULL)

Protected Member Functions inherited from SkRefCntBase
void	internal_dispose_restore_refcnt_to_1 () const
	Allow subclasses to call this if they've overridden internal_dispose so they can reset fRefCnt before the destructor is called or if they choose not to call the destructor (e.g. More...

Private Types
enum	PrivateSaveLayerFlags { kDontClipToLayer_PrivateSaveLayerFlag = 1U << 31 }

enum	ShaderOverrideOpacity { kNone_ShaderOverrideOpacity, kOpaque_ShaderOverrideOpacity, kNotOpaque_ShaderOverrideOpacity }

enum	{ kMCRecSize = 128, kMCRecCount = 32, kDeviceCMSize = 176 }

enum	InitFlags { kDefault_InitFlags = 0, kConservativeRasterClip_InitFlag = 1 << 0 }

typedef SkRefCnt	INHERITED

Private Member Functions
SkBaseDevice *	getTopDevice (bool updateMatrixClip=false) const
	saveLayer() can create another device (which is later drawn onto the previous device). More...

void	predrawNotify (bool willOverwritesEntireSurface=false)

void	predrawNotify (const SkRect rect, const SkPaint paint, ShaderOverrideOpacity)

void	predrawNotify (const SkRect rect, const SkPaint paint, bool shaderOverrideIsOpaque)

SkSurface_Base *	getSurfaceBase () const

void	setSurfaceBase (SkSurface_Base *sb)

void	updateDeviceCMCache ()

void	doSave ()

void	checkForDeferredSave ()

void	internalSetMatrix (const SkMatrix &)

	SkCanvas (const SkIRect &bounds, InitFlags)

	SkCanvas (SkBaseDevice *device, InitFlags)

void	resetForNextPicture (const SkIRect &bounds)

void	setupDevice (SkBaseDevice *)

SkBaseDevice *	init (SkBaseDevice *, InitFlags)

SkIRect	getTopLayerBounds () const
	Gets the bounds of the top level layer in global canvas coordinates. More...

void	internalDrawBitmapRect (const SkBitmap &bitmap, const SkRect src, const SkRect &dst, const SkPaint paint, SrcRectConstraint)

void	internalDrawPaint (const SkPaint &paint)

void	internalSaveLayer (const SaveLayerRec &, SaveLayerStrategy)

void	internalDrawDevice (SkBaseDevice , int x, int y, const SkPaint )

void	internalSave ()

void	internalRestore ()

const SkRegion &	internal_private_getTotalClip () const

bool	wouldOverwriteEntireSurface (const SkRect , const SkPaint , ShaderOverrideOpacity) const

bool	canDrawBitmapAsSprite (SkScalar x, SkScalar y, int w, int h, const SkPaint &)
	Returns true if the paint's imagefilter can be invoked directly, without needed a layer.

void	validateClip () const

Static Private Member Functions
static bool	BoundsAffectsClip (SaveLayerFlags)

static SaveLayerFlags	LegacySaveFlagsToSaveLayerFlags (uint32_t legacySaveFlags)

static void	DrawDeviceWithFilter (SkBaseDevice src, const SkImageFilter filter, SkBaseDevice dst, const SkMatrix &ctm, const SkClipStack clipStack)

static void	DrawRect (const SkDraw &draw, const SkPaint &paint, const SkRect &r, SkScalar textSize)

static void	DrawTextDecorations (const SkDraw &draw, const SkPaint &paint, const char text[], size_t byteLength, SkScalar x, SkScalar y)

Private Attributes
SkAutoTUnref< SkClipStack >	fClipStack

SkDeque	fMCStack

MCRec *	fMCRec

intptr_t	fMCRecStorage [kMCRecSize *kMCRecCount/sizeof(intptr_t)]

intptr_t	fDeviceCMStorage [kDeviceCMSize/sizeof(intptr_t)]

const SkSurfaceProps	fProps

int	fSaveCount

SkMetaData *	fMetaData

SkSurface_Base *	fSurfaceBase

bool	fDeviceCMDirty

bool	fIsScaleTranslate
	Keep track of the device clip bounds and if the matrix is scale-translate. More...

SkRect	fDeviceClipBounds

bool	fAllowSoftClip

bool	fAllowSimplifyClip

const bool	fConservativeRasterClip

Friends
class	SkSurface_Base

class	SkSurface_Gpu

class	SkDrawIter

class	AutoDrawLooper

class	SkLua

class	SkDebugCanvas

class	SkSurface_Raster

class	SkRecorder

class	SkLiteRecorder

class	SkNoSaveLayerCanvas

class	SkPictureImageFilter

class	SkPictureRecord

class	SkPicturePlayback

class	SkCanvasStateUtils

Detailed Description

A Canvas encapsulates all of the state about drawing into a device (bitmap).

This includes a reference to the device itself, and a stack of matrix/clip values. For any given draw call (e.g. drawRect), the geometry of the object being drawn is transformed by the concatenation of all the matrices in the stack. The transformed geometry is clipped by the intersection of all of the clips in the stack.

While the Canvas holds the state of the drawing device, the state (style) of the object being drawn is held by the Paint, which is provided as a parameter to each of the draw() methods. The Paint holds attributes such as color, typeface, textSize, strokeWidth, shader (e.g. gradients, patterns), etc.

Member Enumeration Documentation

enum SkCanvas::PointMode

Enumerator
kPoints_PointMode	drawPoints draws each point separately
kLines_PointMode	drawPoints draws each pair of points as a line segment
kPolygon_PointMode	drawPoints draws the array of points as a polygon

enum SkCanvas::ShaderOverrideOpacity

private

Enumerator
kNone_ShaderOverrideOpacity	there is no overriding shader (bitmap or image)
kOpaque_ShaderOverrideOpacity	the overriding shader is opaque
kNotOpaque_ShaderOverrideOpacity	the overriding shader may not be opaque

enum SkCanvas::SrcRectConstraint

Controls the behavior at the edge of the src-rect, when specified in drawImageRect, trading off speed for exactness.

When filtering is enabled (in the Paint), skia may need to sample in a neighborhood around the pixels in the image. If there is a src-rect specified, it is intended to restrict the pixels that will be read. However, for performance reasons, some implementations may slow down if they cannot read 1-pixel past the src-rect boundary at times.

This enum allows the caller to specify if such a 1-pixel "slop" will be visually acceptable. If it is, the caller should pass kFast, and it may result in a faster draw. If the src-rect must be strictly respected, the caller should pass kStrict.

Enumerator

kStrict_SrcRectConstraint

If kStrict is specified, the implementation must respect the src-rect (if specified) strictly, and will never sample outside of those bounds during sampling even when filtering.

This may be slower than kFast.

kFast_SrcRectConstraint

If kFast is specified, the implementation may sample outside of the src-rect (if specified) by half the width of filter.

This allows greater flexibility to the implementation and can make the draw much faster.

Constructor & Destructor Documentation

SkCanvas::SkCanvas	(	int	width,
		int	height,
		const SkSurfaceProps *	= `NULL`
	)

Creates a canvas of the specified dimensions, but explicitly not backed by any device/pixels.

Typically this use used by subclasses who handle the draw calls in some other way.

SkCanvas::SkCanvas ( SkBaseDevice * device )

explicit

Construct a canvas with the specified device to draw into.

Parameters

device Specifies a device for the canvas to draw into.

SkCanvas::SkCanvas ( const SkBitmap & bitmap )

explicit

Construct a canvas with the specified bitmap to draw into.

Parameters

bitmap Specifies a bitmap for the canvas to draw into. Its structure are copied to the canvas.

SkCanvas::SkCanvas	(	const SkBitmap &	bitmap,
		const SkSurfaceProps &	props
	)

Construct a canvas with the specified bitmap to draw into.

Parameters

bitmap	Specifies a bitmap for the canvas to draw into. Its structure are copied to the canvas.
props	New canvas surface properties.

Member Function Documentation

void* SkCanvas::accessTopLayerPixels	(	SkImageInfo *	info,
		size_t *	rowBytes,
		SkIPoint *	origin = `NULL`
	)

If the canvas has writable pixels in its top layer (and is not recording to a picture or other non-raster target) and has direct access to its pixels (i.e.

they are in local RAM) return the address of those pixels, and if not null, return the ImageInfo, rowBytes and origin. The returned address is only valid while the canvas object is in scope and unchanged. Any API calls made on canvas (or its parent surface if any) will invalidate the returned address (and associated information).

On failure, returns NULL and the info, rowBytes, and origin parameters are ignored.

void SkCanvas::clipPath	(	const SkPath &	path,
		SkRegion::Op	op = `SkRegion::kIntersect_Op`,
		bool	doAntiAlias = `false`
	)

Modify the current clip with the specified path.

Parameters

path	The path to combine with the current clip
op	The region op to apply to the current clip
doAntiAlias	true if the clip should be antialiased

void SkCanvas::clipRect	(	const SkRect &	rect,
		SkRegion::Op	op = `SkRegion::kIntersect_Op`,
		bool	doAntiAlias = `false`
	)

Modify the current clip with the specified rectangle.

Parameters

rect	The rect to combine with the current clip
op	The region op to apply to the current clip
doAntiAlias	true if the clip should be antialiased

void SkCanvas::clipRegion	(	const SkRegion &	deviceRgn,
		SkRegion::Op	op = `SkRegion::kIntersect_Op`
	)

Modify the current clip with the specified region.

Note that unlike clipRect() and clipPath() which transform their arguments by the current matrix, clipRegion() assumes its argument is already in device coordinates, and so no transformation is performed.

Parameters

deviceRgn	The region to apply to the current clip
op	The region op to apply to the current clip

void SkCanvas::clipRRect	(	const SkRRect &	rrect,
		SkRegion::Op	op = `SkRegion::kIntersect_Op`,
		bool	doAntiAlias = `false`
	)

Modify the current clip with the specified SkRRect.

Parameters

rrect	The rrect to combine with the current clip
op	The region op to apply to the current clip
doAntiAlias	true if the clip should be antialiased

void SkCanvas::concat ( const SkMatrix & matrix )

Preconcat the current matrix with the specified matrix.

Parameters

matrix The matrix to preconcatenate with the current matrix

void SkCanvas::discard ( )

inline

This makes the contents of the canvas undefined.

Subsequent calls that require reading the canvas contents will produce undefined results. Examples include blending and readPixels. The actual implementation is backend- dependent and one legal implementation is to do nothing. This method ignores the current clip.

This function should only be called if the caller intends to subsequently draw to the canvas. The canvas may do real work at discard() time in order to optimize performance on subsequent draws. Thus, if you call this and then never draw to the canvas subsequently you may pay a perfomance penalty.

void SkCanvas::drawAnnotation	(	const SkRect &	,
		const char	key[],
		SkData *	value
	)

Send an "annotation" to the canvas.

The annotation is a key/value pair, where the key is a null-terminated utf8 string, and the value is a blob of data stored in an SkData (which may be null). The annotation is associated with the specified rectangle.

The caller still retains its ownership of the data (if any).

Note: on may canvas types, this information is ignored, but some canvases (e.g. recording a picture or drawing to a PDF document) will pass on this information.

void SkCanvas::drawArc	(	const SkRect &	oval,
		SkScalar	startAngle,
		SkScalar	sweepAngle,
		bool	useCenter,
		const SkPaint &	paint
	)

Draw the specified arc, which will be scaled to fit inside the specified oval.

If the sweep angle is >= 360, then the oval is drawn completely. Note that this differs slightly from SkPath::arcTo, which treats the sweep angle mod 360.

Parameters

oval	The bounds of oval used to define the shape of the arc.
startAngle	Starting angle (in degrees) where the arc begins
sweepAngle	Sweep angle (in degrees) measured clockwise.
useCenter	true means include the center of the oval. For filling this will draw a wedge. False means just use the arc.
paint	The paint used to draw the arc

void SkCanvas::drawARGB	(	U8CPU	a,
		U8CPU	r,
		U8CPU	g,
		U8CPU	b,
		SkXfermode::Mode	mode = `SkXfermode::kSrcOver_Mode`
	)

Fill the entire canvas' bitmap (restricted to the current clip) with the specified ARGB color, using the specified mode.

Parameters

a	the alpha component (0..255) of the color to fill the canvas
r	the red component (0..255) of the color to fill the canvas
g	the green component (0..255) of the color to fill the canvas
b	the blue component (0..255) of the color to fill the canvas
mode	the mode to apply the color in (defaults to SrcOver)

void SkCanvas::drawAtlas	(	const SkImage *	atlas,
		const SkRSXform	xform[],
		const SkRect	tex[],
		const SkColor	colors[],
		int	count,
		SkXfermode::Mode	,
		const SkRect *	cullRect,
		const SkPaint *	paint
	)

Draw a set of sprites from the atlas.

Each is specified by a tex rectangle in the coordinate space of the atlas, and a corresponding xform which transforms the tex rectangle into a quad.

xform maps [0, 0, tex.width, tex.height] -> quad

The color array is optional. When specified, each color modulates the pixels in its corresponding quad (via the specified SkXfermode::Mode).

The cullRect is optional. When specified, it must be a conservative bounds of all of the resulting transformed quads, allowing the canvas to skip drawing if the cullRect does not intersect the current clip.

The paint is optional. If specified, its antialiasing, alpha, color-filter, image-filter and xfermode are used to affect each of the quads.

void SkCanvas::drawBitmap	(	const SkBitmap &	bitmap,
		SkScalar	left,
		SkScalar	top,
		const SkPaint *	paint = `NULL`
	)

Draw the specified bitmap, with its top/left corner at (x,y), using the specified paint, transformed by the current matrix.

Note: if the paint contains a maskfilter that generates a mask which extends beyond the bitmap's original width/height, then the bitmap will be drawn as if it were in a Shader with CLAMP mode. Thus the color outside of the original width/height will be the edge color replicated.

If a shader is present on the paint it will be ignored, except in the case where the bitmap is kAlpha_8_SkColorType. In that case, the color is generated by the shader.

Parameters

bitmap	The bitmap to be drawn
left	The position of the left side of the bitmap being drawn
top	The position of the top side of the bitmap being drawn
paint	The paint used to draw the bitmap, or NULL

void SkCanvas::drawBitmapLattice	(	const SkBitmap &	bitmap,
		const Lattice &	lattice,
		const SkRect &	dst,
		const SkPaint *	paint = `nullptr`
	)

Draw the bitmap stretched or shrunk differentially to fit into dst.

Moving horizontally across the bitmap, alternating rects will be "scalable" (in the x-dimension) to fit into dst or must be left "fixed". The first rect is treated as "fixed", but it's possible to specify an empty first rect by making lattice.fXDivs[0] = 0.

The scale factor for all "scalable" rects will be the same, and may be greater than or less than 1 (meaning we can stretch or shrink). If the number of "fixed" pixels is greater than the width of the dst, we will collapse all of the "scalable" regions and appropriately downscale the "fixed" regions.

The same interpretation also applies to the y-dimension.

void SkCanvas::drawBitmapNine	(	const SkBitmap &	bitmap,
		const SkIRect &	center,
		const SkRect &	dst,
		const SkPaint *	paint = `NULL`
	)

Draw the bitmap stretched or shrunk differentially to fit into dst.

center is a rect within the bitmap, and logically divides the bitmap into 9 sections (3x3). For example, if the middle pixel of a [5x5] bitmap is the "center", then the center-rect should be [2, 2, 3, 3].

If the dst is >= the bitmap size, then...

The 4 corners are not stretched at all.
The sides are stretched in only one axis.
The center is stretched in both axes. Else, for each axis where dst < bitmap,
The corners shrink proportionally
The sides (along the shrink axis) and center are not drawn

void SkCanvas::drawBitmapRect	(	const SkBitmap &	bitmap,
		const SkRect &	src,
		const SkRect &	dst,
		const SkPaint *	paint,
		SrcRectConstraint	= `kStrict_SrcRectConstraint`
	)

Draw the specified bitmap, scaling and translating so that it fills the specified dst rect.

If the src rect is non-null, only that subset of the bitmap is transformed and drawn.

Parameters

bitmap	The bitmap to be drawn
src	Optional: specify the subset of the bitmap to be drawn
dst	The destination rectangle where the scaled/translated bitmap will be drawn
paint	The paint used to draw the bitmap, or NULL
constraint	Control the tradeoff between speed and exactness w.r.t. the src-rect.

void SkCanvas::drawCircle	(	SkScalar	cx,
		SkScalar	cy,
		SkScalar	radius,
		const SkPaint &	paint
	)

Draw the specified circle using the specified paint.

If radius is <= 0, then nothing will be drawn. The circle will be filled or framed based on the Style in the paint.

Parameters

cx	The x-coordinate of the center of the cirle to be drawn
cy	The y-coordinate of the center of the cirle to be drawn
radius	The radius of the cirle to be drawn
paint	The paint used to draw the circle

void SkCanvas::drawColor	(	SkColor	color,
		SkXfermode::Mode	mode = `SkXfermode::kSrcOver_Mode`
	)

Fill the entire canvas' bitmap (restricted to the current clip) with the specified color and mode.

Parameters

color	the color to draw with
mode	the mode to apply the color in (defaults to SrcOver)

void SkCanvas::drawDrawable	(	SkDrawable *	drawable,
		const SkMatrix *	= `NULL`
	)

Draw the contents of this drawable into the canvas.

If the canvas is async (e.g. it is recording into a picture) then the drawable will be referenced instead, to have its draw() method called when the picture is finalized.

If the intent is to force the contents of the drawable into this canvas immediately, then drawable->draw(canvas) may be called.

void SkCanvas::drawDRRect	(	const SkRRect &	outer,
		const SkRRect &	inner,
		const SkPaint &
	)

Draw the annulus formed by the outer and inner rrects.

The results are undefined if the outer does not contain the inner.

void SkCanvas::drawImage	(	const SkImage *	image,
		SkScalar	left,
		SkScalar	top,
		const SkPaint *	paint = `NULL`
	)

Draw the specified image, with its top/left corner at (x,y), using the specified paint, transformed by the current matrix.

Parameters

image	The image to be drawn
left	The position of the left side of the image being drawn
top	The position of the top side of the image being drawn
paint	The paint used to draw the image, or NULL

void SkCanvas::drawImageNine	(	const SkImage *	,
		const SkIRect &	center,
		const SkRect &	dst,
		const SkPaint *	paint = `nullptr`
	)

Draw the image stretched differentially to fit into dst.

center is a rect within the image, and logically divides the image into 9 sections (3x3). For example, if the middle pixel of a [5x5] image is the "center", then the center-rect should be [2, 2, 3, 3].

If the dst is >= the image size, then...

The 4 corners are not stretched at all.
The sides are stretched in only one axis.
The center is stretched in both axes. Else, for each axis where dst < image,
The corners shrink proportionally
The sides (along the shrink axis) and center are not drawn

void SkCanvas::drawImageRect	(	const SkImage *	image,
		const SkRect &	src,
		const SkRect &	dst,
		const SkPaint *	paint,
		SrcRectConstraint	constraint = `kStrict_SrcRectConstraint`
	)

Draw the specified image, scaling and translating so that it fills the specified dst rect.

If the src rect is non-null, only that subset of the image is transformed and drawn.

Parameters

image	The image to be drawn
src	Optional: specify the subset of the image to be drawn
dst	The destination rectangle where the scaled/translated image will be drawn
paint	The paint used to draw the image, or NULL
constraint	Control the tradeoff between speed and exactness w.r.t. the src-rect.

void SkCanvas::drawIRect	(	const SkIRect &	rect,
		const SkPaint &	paint
	)

inline

Draw the specified rectangle using the specified paint.

The rectangle will be filled or framed based on the Style in the paint.

Parameters

rect	The rect to be drawn
paint	The paint used to draw the rect

void SkCanvas::drawLine	(	SkScalar	x0,
		SkScalar	y0,
		SkScalar	x1,
		SkScalar	y1,
		const SkPaint &	paint
	)

Draw a line segment with the specified start and stop x,y coordinates, using the specified paint.

NOTE: since a line is always "framed", the paint's Style is ignored.

Parameters

x0	The x-coordinate of the start point of the line
y0	The y-coordinate of the start point of the line
x1	The x-coordinate of the end point of the line
y1	The y-coordinate of the end point of the line
paint	The paint used to draw the line

void SkCanvas::drawOval	(	const SkRect &	oval,
		const SkPaint &
	)

Draw the specified oval using the specified paint.

The oval will be filled or framed based on the Style in the paint.

Parameters

oval	The rectangle bounds of the oval to be drawn
paint	The paint used to draw the oval

void SkCanvas::drawPaint ( const SkPaint & paint )

Fill the entire canvas (restricted to the current clip) with the specified paint.

Parameters

paint The paint used to fill the canvas

void SkCanvas::drawPatch	(	const SkPoint	cubics[12],
		const SkColor	colors[4],
		const SkPoint	texCoords[4],
		SkXfermode *	xmode,
		const SkPaint &	paint
	)

Draw a cubic coons patch.

Parameters

cubic	specifies the 4 bounding cubic bezier curves of a patch with clockwise order starting at the top left corner.
colors	specifies the colors for the corners which will be bilerp across the patch, their order is clockwise starting at the top left corner.
texCoords	specifies the texture coordinates that will be bilerp across the patch, their order is the same as the colors.
xmode	specifies how are the colors and the textures combined if both of them are present.
paint	Specifies the shader/texture if present.

void SkCanvas::drawPath	(	const SkPath &	path,
		const SkPaint &	paint
	)

Draw the specified path using the specified paint.

The path will be filled or framed based on the Style in the paint.

Parameters

path	The path to be drawn
paint	The paint used to draw the path

void SkCanvas::drawPicture ( const SkPicture * picture )

inline

Draw the picture into this canvas.

This method effective brackets the playback of the picture's draw calls with save/restore, so the state of this canvas will be unchanged after this call.

Parameters

picture The recorded drawing commands to playback into this canvas.

void SkCanvas::drawPicture	(	const SkPicture *	,
		const SkMatrix *	matrix,
		const SkPaint *	paint
	)

Draw the picture into this canvas.

If matrix is non-null, apply that matrix to the CTM when drawing this picture. This is logically equivalent to save/concat/drawPicture/restore

If paint is non-null, draw the picture into a temporary buffer, and then apply the paint's alpha/colorfilter/imagefilter/xfermode to that buffer as it is drawn to the canvas. This is logically equivalent to saveLayer(paint)/drawPicture/restore

void SkCanvas::drawPoint	(	SkScalar	x,
		SkScalar	y,
		const SkPaint &	paint
	)

Helper method for drawing a single point.

See drawPoints() for a more details.

void SkCanvas::drawPoint	(	SkScalar	x,
		SkScalar	y,
		SkColor	color
	)

Draws a single pixel in the specified color.

Parameters

x	The X coordinate of which pixel to draw
y	The Y coordiante of which pixel to draw
color	The color to draw

void SkCanvas::drawPoints	(	PointMode	mode,
		size_t	count,
		const SkPoint	pts[],
		const SkPaint &	paint
	)

Draw a series of points, interpreted based on the PointMode mode.

For all modes, the count parameter is interpreted as the total number of points. For kLine mode, count/2 line segments are drawn. For kPoint mode, each point is drawn centered at its coordinate, and its size is specified by the paint's stroke-width. It draws as a square, unless the paint's cap-type is round, in which the points are drawn as circles. For kLine mode, each pair of points is drawn as a line segment, respecting the paint's settings for cap/join/width. For kPolygon mode, the entire array is drawn as a series of connected line segments. Note that, while similar, kLine and kPolygon modes draw slightly differently than the equivalent path built with a series of moveto, lineto calls, in that the path will draw all of its contours at once, with no interactions if contours intersect each other (think XOR xfermode). drawPoints always draws each element one at a time.

Parameters

mode	PointMode specifying how to draw the array of points.
count	The number of points in the array
pts	Array of points to draw
paint	The paint used to draw the points

void SkCanvas::drawPosText	(	const void *	text,
		size_t	byteLength,
		const SkPoint	pos[],
		const SkPaint &	paint
	)

Draw the text, with each character/glyph origin specified by the pos[] array.

The origin is interpreted by the Align setting in the paint.

Parameters

text	The text to be drawn
byteLength	The number of bytes to read from the text parameter
pos	Array of positions, used to position each character
paint	The paint used for the text (e.g. color, size, style)

void SkCanvas::drawPosTextH	(	const void *	text,
		size_t	byteLength,
		const SkScalar	xpos[],
		SkScalar	constY,
		const SkPaint &	paint
	)

Draw the text, with each character/glyph origin specified by the x coordinate taken from the xpos[] array, and the y from the constY param.

The origin is interpreted by the Align setting in the paint.

Parameters

text	The text to be drawn
byteLength	The number of bytes to read from the text parameter
xpos	Array of x-positions, used to position each character
constY	The shared Y coordinate for all of the positions
paint	The paint used for the text (e.g. color, size, style)

void SkCanvas::drawRect	(	const SkRect &	rect,
		const SkPaint &	paint
	)

Draw the specified rectangle using the specified paint.

The rectangle will be filled or stroked based on the Style in the paint.

Parameters

rect	The rect to be drawn
paint	The paint used to draw the rect

void SkCanvas::drawRectCoords	(	SkScalar	left,
		SkScalar	top,
		SkScalar	right,
		SkScalar	bottom,
		const SkPaint &	paint
	)

Draw the specified rectangle using the specified paint.

The rectangle will be filled or framed based on the Style in the paint.

Parameters

left	The left side of the rectangle to be drawn
top	The top side of the rectangle to be drawn
right	The right side of the rectangle to be drawn
bottom	The bottom side of the rectangle to be drawn
paint	The paint used to draw the rect

void SkCanvas::drawRoundRect	(	const SkRect &	rect,
		SkScalar	rx,
		SkScalar	ry,
		const SkPaint &	paint
	)

Draw the specified round-rect using the specified paint.

The round-rect will be filled or framed based on the Style in the paint.

Parameters

rect	The rectangular bounds of the roundRect to be drawn
rx	The x-radius of the oval used to round the corners
ry	The y-radius of the oval used to round the corners
paint	The paint used to draw the roundRect

void SkCanvas::drawRRect	(	const SkRRect &	rrect,
		const SkPaint &	paint
	)

Draw the specified RRect using the specified paint The rrect will be filled or stroked based on the Style in the paint.

Parameters

rrect	The round-rect to draw
paint	The paint used to draw the round-rect

void SkCanvas::drawText	(	const void *	text,
		size_t	byteLength,
		SkScalar	x,
		SkScalar	y,
		const SkPaint &	paint
	)

Draw the text, with origin at (x,y), using the specified paint.

The origin is interpreted based on the Align setting in the paint.

Parameters

text	The text to be drawn
byteLength	The number of bytes to read from the text parameter
x	The x-coordinate of the origin of the text being drawn
y	The y-coordinate of the origin of the text being drawn
paint	The paint used for the text (e.g. color, size, style)

void SkCanvas::drawTextBlob	(	const SkTextBlob *	blob,
		SkScalar	x,
		SkScalar	y,
		const SkPaint &	paint
	)

Draw the text blob, offset by (x,y), using the specified paint.

Parameters

blob	The text blob to be drawn
x	The x-offset of the text being drawn
y	The y-offset of the text being drawn
paint	The paint used for the text (e.g. color, size, style)

void SkCanvas::drawTextOnPath	(	const void *	text,
		size_t	byteLength,
		const SkPath &	path,
		const SkMatrix *	matrix,
		const SkPaint &	paint
	)

Draw the text, with origin at (x,y), using the specified paint, along the specified path.

The paint's Align setting determins where along the path to start the text.

Parameters

text	The text to be drawn
byteLength	The number of bytes to read from the text parameter
path	The path the text should follow for its baseline
matrix	(may be null) Applied to the text before it is mapped onto the path
paint	The paint used for the text

void SkCanvas::drawTextOnPathHV	(	const void *	text,
		size_t	byteLength,
		const SkPath &	path,
		SkScalar	hOffset,
		SkScalar	vOffset,
		const SkPaint &	paint
	)

Draw the text, with origin at (x,y), using the specified paint, along the specified path.

The paint's Align setting determins where along the path to start the text.

Parameters

text	The text to be drawn
byteLength	The number of bytes to read from the text parameter
path	The path the text should follow for its baseline
hOffset	The distance along the path to add to the text's starting position
vOffset	The distance above(-) or below(+) the path to position the text
paint	The paint used for the text

void SkCanvas::drawTextRSXform	(	const void *	text,
		size_t	byteLength,
		const SkRSXform	[],
		const SkRect *	cullRect,
		const SkPaint &	paint
	)

Draw the text with each character/glyph individually transformed by its xform.

If cullRect is not null, it is a conservative bounds of what will be drawn taking into account the xforms and the paint, and will be used to accelerate culling.

void SkCanvas::drawVertices	(	VertexMode	vmode,
		int	vertexCount,
		const SkPoint	vertices[],
		const SkPoint	texs[],
		const SkColor	colors[],
		SkXfermode *	xmode,
		const uint16_t	indices[],
		int	indexCount,
		const SkPaint &	paint
	)

Draw the array of vertices, interpreted as triangles (based on mode).

If both textures and vertex-colors are NULL, it strokes hairlines with the paint's color. This behavior is a useful debugging mode to visualize the mesh.

Parameters

vmode	How to interpret the array of vertices
vertexCount	The number of points in the vertices array (and corresponding texs and colors arrays if non-null)
vertices	Array of vertices for the mesh
texs	May be null. If not null, specifies the coordinate in texture space (not uv space) for each vertex.
colors	May be null. If not null, specifies a color for each vertex, to be interpolated across the triangle.
xmode	Used if both texs and colors are present. In this case the colors are combined with the texture using mode, before being drawn using the paint. If mode is null, then kModulate_Mode is used.
indices	If not null, array of indices to reference into the vertex (texs, colors) array.
indexCount	number of entries in the indices array (if not null)
paint	Specifies the shader/texture if present.

void SkCanvas::flush ( )

Trigger the immediate execution of all pending draw operations.

For the GPU backend this will resolve all rendering to the GPU surface backing the SkSurface that owns this canvas.

virtual SkISize SkCanvas::getBaseLayerSize ( ) const

virtual

Gets the size of the base or root layer in global canvas coordinates.

The origin of the base layer is always (0,0). The current drawable area may be smaller (due to clipping or saveLayer).

virtual bool SkCanvas::getClipBounds ( SkRect * bounds ) const

virtual

Return the bounds of the current clip (in local coordinates) in the bounds parameter, and return true if it is non-empty.

This can be useful in a way similar to quickReject, in that it tells you that drawing outside of these bounds will be clipped out.

virtual bool SkCanvas::getClipDeviceBounds ( SkIRect * bounds ) const

virtual

Return the bounds of the current clip, in device coordinates; returns true if non-empty.

Maybe faster than getting the clip explicitly and then taking its bounds.

const SkClipStack* SkCanvas::getClipStack ( ) const

inline

Return the clip stack.

The clip stack stores all the individual clips organized by the save/restore frame in which they were added.

Returns: the current clip stack ("list" of individual clip elements)

SkBaseDevice* SkCanvas::getDevice ( ) const

protected

DEPRECATED.

Return the canvas' device object, which may be null. The device holds the bitmap of the pixels that the canvas draws into. The reference count of the returned device is not changed by this call.

GrContext* SkCanvas::getGrContext ( )

Return the GPU context of the device that is associated with the canvas.

For a canvas with non-GPU device, NULL is returned.

bool SkCanvas::getProps ( SkSurfaceProps * ) const

If the canvas is backed by pixels (cpu or gpu), this writes a copy of the SurfaceProps for the canvas to the location supplied by the caller, and returns true.

Otherwise, return false and leave the supplied props unchanged.

int SkCanvas::getSaveCount ( ) const

Returns the number of matrix/clip states on the SkCanvas' private stack.

This will equal # save() calls - # restore() calls + 1. The save count on a new canvas is 1.

SkBaseDevice* SkCanvas::getTopDevice ( bool updateMatrixClip = false ) const

private

saveLayer() can create another device (which is later drawn onto the previous device).

getTopDevice() returns the top-most device current installed. Note that this can change on other calls like save/restore, so do not access this device after subsequent canvas calls. The reference count of the device is not changed.

Parameters

updateMatrixClip If this is true, then before the device is returned, we ensure that its has been notified about the current matrix and clip. Note: this happens automatically when the device is drawn to, but is optional here, as there is a small perf hit sometimes.

SkIRect SkCanvas::getTopLayerBounds ( ) const

private

Gets the bounds of the top level layer in global canvas coordinates.

We don't want this to be public because it exposes decisions about layer sizes that are internal to the canvas.

const SkMatrix& SkCanvas::getTotalMatrix ( ) const

Return the current matrix on the canvas.

This does not account for the translate in any of the devices.

Returns: The current matrix on the canvas.

SkImageInfo SkCanvas::imageInfo ( ) const

Return ImageInfo for this canvas.

If the canvas is not backed by pixels (cpu or gpu), then the info's ColorType will be kUnknown_SkColorType.

virtual bool SkCanvas::isClipEmpty ( ) const

virtual

Return true if the current clip is empty (i.e.

nothing will draw). Note: this is not always a free call, so it should not be used more often than necessary. However, once the canvas has computed this result, subsequent calls will be cheap (until the clip state changes, which can happen on any clip..() or restore() call.

virtual bool SkCanvas::isClipRect ( ) const

virtual

Returns true if the current clip is just a (non-empty) rectangle.

Returns false if the clip is empty, or if it is complex.

sk_sp<SkSurface> SkCanvas::makeSurface	(	const SkImageInfo &	,
		const SkSurfaceProps *	= `nullptr`
	)

Create a new surface matching the specified info, one that attempts to be maximally compatible when used with this canvas.

If there is no matching Surface type, NULL is returned.

If surfaceprops is specified, those are passed to the new surface, otherwise the new surface inherits the properties of the surface that owns this canvas. If this canvas has no parent surface, then the new surface is created with default properties.

static SkCanvas* SkCanvas::NewRasterDirect	(	const SkImageInfo &	,
		void *	,
		size_t
	)

static

Attempt to allocate raster canvas, matching the ImageInfo, that will draw directly into the specified pixels.

To access the pixels after drawing to them, the caller should call flush() or call peekPixels(...).

On failure, return NULL. This can fail for several reasons:

invalid ImageInfo (e.g. negative dimensions)
unsupported ImageInfo for a canvas
- kUnknown_SkColorType, kIndex_8_SkColorType
- kUnknown_SkAlphaType
- this list is not complete, so others may also be unsupported

Note: it is valid to request a supported ImageInfo, but with zero dimensions.

bool SkCanvas::peekPixels ( SkPixmap * )

If the canvas has readable pixels in its base layer (and is not recording to a picture or other non-raster target) and has direct access to its pixels (i.e.

they are in local RAM) return true, and if not null, return in the pixmap parameter information about the pixels. The pixmap's pixel address is only valid while the canvas object is in scope and unchanged. Any API calls made on canvas (or its parent surface if any) will invalidate the pixel address (and associated information).

On failure, returns false and the pixmap parameter will be ignored.

bool SkCanvas::quickReject ( const SkRect & rect ) const

Return true if the specified rectangle, after being transformed by the current matrix, would lie completely outside of the current clip.

Call this to check if an area you intend to draw into is clipped out (and therefore you can skip making the draw calls).

Parameters

rect	the rect to compare with the current clip

Returns: true if the rect (transformed by the canvas' matrix) does not intersect with the canvas' clip

bool SkCanvas::quickReject ( const SkPath & path ) const

Return true if the specified path, after being transformed by the current matrix, would lie completely outside of the current clip.

Call this to check if an area you intend to draw into is clipped out (and therefore you can skip making the draw calls). Note, for speed it may return false even if the path itself might not intersect the clip (i.e. the bounds of the path intersects, but the path does not).

Parameters

path	The path to compare with the current clip

Returns: true if the path (transformed by the canvas' matrix) does not intersect with the canvas' clip

bool SkCanvas::readPixels	(	const SkImageInfo &	dstInfo,
		void *	dstPixels,
		size_t	dstRowBytes,
		int	srcX,
		int	srcY
	)

Copy the pixels from the base-layer into the specified buffer (pixels + rowBytes), converting them into the requested format (SkImageInfo).

The base-layer pixels are read starting at the specified (srcX,srcY) location in the coordinate system of the base-layer.

The specified ImageInfo and (srcX,srcY) offset specifies a source rectangle

srcR.setXYWH(srcX, srcY, dstInfo.width(), dstInfo.height());

srcR is intersected with the bounds of the base-layer. If this intersection is not empty, then we have two sets of pixels (of equal size). Replace the dst pixels with the corresponding src pixels, performing any colortype/alphatype transformations needed (in the case where the src and dst have different colortypes or alphatypes).

This call can fail, returning false, for several reasons:

If srcR does not intersect the base-layer bounds.
If the requested colortype/alphatype cannot be converted from the base-layer's types.
If this canvas is not backed by pixels (e.g. picture or PDF)

bool SkCanvas::readPixels	(	SkBitmap *	bitmap,
		int	srcX,
		int	srcY
	)

Helper for calling readPixels(info, ...).

This call will check if bitmap has been allocated. If not, it will attempt to call allocPixels(). If this fails, it will return false. If not, it calls through to readPixels(info, ...) and returns its result.

bool SkCanvas::readPixels	(	const SkIRect &	srcRect,
		SkBitmap *	bitmap
	)

Helper for allocating pixels and then calling readPixels(info, ...).

The bitmap is resized to the intersection of srcRect and the base-layer bounds. On success, pixels will be allocated in bitmap and true returned. On failure, false is returned and bitmap will be set to empty.

void SkCanvas::replayClips ( ClipVisitor * ) const

Replays the clip operations, back to front, that have been applied to the canvas, calling the appropriate method on the visitor for each clip.

All clips have already been transformed into device space.

void SkCanvas::resetMatrix ( )

Helper for setMatrix(identity).

Sets the current matrix to identity.

void SkCanvas::restore ( )

This call balances a previous call to save(), and is used to remove all modifications to the matrix/clip/drawFilter state since the last save call.

It is an error to call restore() more times than save() was called.

void SkCanvas::restoreToCount ( int saveCount )

Efficient way to pop any calls to save() that happened after the save count reached saveCount.

It is an error for saveCount to be greater than getSaveCount(). To pop all the way back to the initial matrix/clip context pass saveCount == 1.

Parameters

saveCount The number of save() levels to restore from

void SkCanvas::rotate ( SkScalar degrees )

Preconcat the current matrix with the specified rotation about the origin.

Parameters

degrees The amount to rotate, in degrees

void SkCanvas::rotate	(	SkScalar	degrees,
		SkScalar	px,
		SkScalar	py
	)

Preconcat the current matrix with the specified rotation about a given point.

Parameters

degrees	The amount to rotate, in degrees
px	The x coordinate of the point to rotate about.
py	The y coordinate of the point to rotate about.

int SkCanvas::save ( )

This call saves the current matrix, clip, and drawFilter, and pushes a copy onto a private stack.

Subsequent calls to translate, scale, rotate, skew, concat or clipRect, clipPath, and setDrawFilter all operate on this copy. When the balancing call to restore() is made, the previous matrix, clip, and drawFilter are restored.

Returns: The value to pass to restoreToCount() to balance this save()

int SkCanvas::saveLayer	(	const SkRect *	bounds,
		const SkPaint *	paint
	)

This behaves the same as save(), but in addition it allocates an offscreen bitmap.

All drawing calls are directed there, and only when the balancing call to restore() is made is that offscreen transfered to the canvas (or the previous layer).

Parameters

bounds	(may be null) This rect, if non-null, is used as a hint to limit the size of the offscreen, and thus drawing may be clipped to it, though that clipping is not guaranteed to happen. If exact clipping is desired, use clipRect().
paint	(may be null) This is copied, and is applied to the offscreen when restore() is called

Returns: The value to pass to restoreToCount() to balance this save()

int SkCanvas::saveLayerAlpha	(	const SkRect *	bounds,
		U8CPU	alpha
	)

This behaves the same as save(), but in addition it allocates an offscreen bitmap.

All drawing calls are directed there, and only when the balancing call to restore() is made is that offscreen transfered to the canvas (or the previous layer).

Parameters

bounds	(may be null) This rect, if non-null, is used as a hint to limit the size of the offscreen, and thus drawing may be clipped to it, though that clipping is not guaranteed to happen. If exact clipping is desired, use clipRect().
alpha	This is applied to the offscreen when restore() is called.

Returns: The value to pass to restoreToCount() to balance this save()

int SkCanvas::saveLayerPreserveLCDTextRequests	(	const SkRect *	bounds,
		const SkPaint *	paint
	)

Temporary name.

Will allow any requests for LCD text to be respected, so the caller must be careful to only draw on top of opaque sections of the layer to get good results.

void SkCanvas::scale	(	SkScalar	sx,
		SkScalar	sy
	)

Preconcat the current matrix with the specified scale.

Parameters

sx	The amount to scale in X
sy	The amount to scale in Y

void SkCanvas::setClipRegion ( const SkRegion & deviceRgn )

inline

Helper for clipRegion(rgn, kReplace_Op).

Sets the current clip to the specified region. This does not intersect or in any other way account for the existing clip region.

Parameters

deviceRgn The region to copy into the current clip.

void SkCanvas::setMatrix ( const SkMatrix & matrix )

Replace the current matrix with a copy of the specified matrix.

Parameters

matrix The matrix that will be copied into the current matrix.

void SkCanvas::skew	(	SkScalar	sx,
		SkScalar	sy
	)

Preconcat the current matrix with the specified skew.

Parameters

sx	The amount to skew in X
sy	The amount to skew in Y

void SkCanvas::translate	(	SkScalar	dx,
		SkScalar	dy
	)

Preconcat the current matrix with the specified translation.

Parameters

dx	The distance to translate in X
dy	The distance to translate in Y

bool SkCanvas::writePixels	(	const SkImageInfo &	,
		const void *	pixels,
		size_t	rowBytes,
		int	x,
		int	y
	)

This method affects the pixels in the base-layer, and operates in pixel coordinates, ignoring the matrix and clip.

The specified ImageInfo and (x,y) offset specifies a rectangle: target.

target.setXYWH(x, y, info.width(), info.height());

Target is intersected with the bounds of the base-layer. If this intersection is not empty, then we have two sets of pixels (of equal size), the "src" specified by info+pixels+rowBytes and the "dst" by the canvas' backend. Replace the dst pixels with the corresponding src pixels, performing any colortype/alphatype transformations needed (in the case where the src and dst have different colortypes or alphatypes).

This call can fail, returning false, for several reasons:

If the src colortype/alphatype cannot be converted to the canvas' types
If this canvas is not backed by pixels (e.g. picture or PDF)

bool SkCanvas::writePixels	(	const SkBitmap &	bitmap,
		int	x,
		int	y
	)

Helper for calling writePixels(info, ...) by passing its pixels and rowbytes.

If the bitmap is just wrapping a texture, returns false and does nothing.

Member Data Documentation

bool SkCanvas::fIsScaleTranslate

private

Keep track of the device clip bounds and if the matrix is scale-translate.

This allows us to do a fast quick reject in the common case.

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

include/core/SkCanvas.h

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