SkCanvas Reference === # Canvas # Class SkCanvas Canvas provides an interface for drawing, and how the drawing is clipped and transformed. Canvas contains a stack of Matrix and Clip values. Canvas and Paint together provide the state to draw into Surface or Device. Each Canvas draw call transforms the geometry of the object by the concatenation of all Matrix values in the stack. The transformed geometry is clipped by the intersection of all of Clip values in the stack. The Canvas draw calls use Paint to supply drawing state such as Color, Typeface, text size, stroke width, Shader and so on. To draw to a pixel-based destination, create Raster Surface or GPU Surface. Request Canvas from Surface to obtain the interface to draw. Canvas generated by Raster Surface draws to memory visible to the CPU. Canvas generated by GPU Surface uses Vulkan or OpenGL to draw to the GPU. To draw to a document, obtain Canvas from SVG Canvas, Document PDF, or Picture Recorder. Document based Canvas and other Canvas Subclasses reference Device describing the destination. Canvas can be constructed to draw to Bitmap without first creating Raster Surface. This approach may be deprecated in the future. ## Overview
Topic Description
Constants enum and enum class, and their const values
Constructors functions that construct SkCanvas
Functions global and class member functions
Related Functions similar member functions grouped together
Struct Declarations embedded struct members
Typedef Declarations types defined by other types
## Related Function SkCanvas global, struct, and class related member functions share a topic.
Topic Description
Clip stack of clipping Paths
Draw draws into Canvas
Draw Image draws Image to Canvas
Draw Image Lattice divides Bitmap or Image into a rectangular grid
Draw Text draws text into Canvas
Layer temporary Bitmap to draw into
Layer SaveLayerRec contains the state used to create the Layer
Matrix coordinate transformation
Pixels read and write pixel values
Property metrics and attributes
State Stack stack of state for hierarchical drawing
Utility rarely called management functions
## Constant SkCanvas related constants are defined by enum, enum class, #define, const, and constexpr.
Topic Description
ColorBehavior::kLegacy placeholder
ColorBehavior exists for Android framework only
PointMode sets drawPoints options
SaveLayerFlagsSet sets SaveLayerRec options
SrcRectConstraint sets drawImageRect options
kFast SrcRectConstraint sample outside bounds; faster
kInitWithPrevious SaveLayerFlag initializes with previous contents
kLines PointMode draw each pair of points as a line segment
kPoints PointMode draw each point separately
kPolygon PointMode draw the array of points as a open polygon
kPreserveLCDText SaveLayerFlag creates Layer for LCD text
kStrict SrcRectConstraint sample only inside bounds; slower
## Struct SkCanvas uses C++ structs to declare the public data structures and interfaces.
Topic Description
Lattice divides Bitmap or Image into a rectangular grid
SaveLayerRec contains the state used to create the Layer
## Typedef SkCanvas typedef define a data type.
Topic Description
SaveLayerFlags options for SaveLayerRec
## Constructor Create the desired type of Surface to obtain its Canvas when possible. Useful when no Surface is required, and some helpers implicitly create Raster Surface. SkCanvas can be constructed or initialized by these functions, including C++ class constructors.
Topic Description
MakeRasterDirect creates from SkImageInfo and Pixel Storage
MakeRasterDirectN32 creates from image data and Pixel Storage
SkCanvas() creates with no Surface, no dimensions
SkCanvas(const SkBitmap& bitmap) uses existing Bitmap
SkCanvas(const SkBitmap& bitmap, ColorBehavior behavior) exists for Android framework only
SkCanvas(const SkBitmap& bitmap, const SkSurfaceProps& props) uses existing Bitmap and Surface Properties
SkCanvas(int width, int height, const SkSurfaceProps* props = nullptr) creates with no Surface, set dimensions, Surface Properties
makeSurface creates Surface matching SkImageInfo and SkSurfaceProps
~SkCanvas() draws saved Layers, frees resources
## Member Function SkCanvas member functions read and modify the structure properties.
Topic Description
MakeRasterDirect creates from SkImageInfo and Pixel Storage
MakeRasterDirectN32 creates from image data and Pixel Storage
accessTopLayerPixels returns writable pixel access if available
accessTopRasterHandle returns context that tracks Clip and Matrix
androidFramework setDeviceClipRestriction exists for use by Android framework
clear fills Clip with Color
clipPath combines Clip with Path
clipRRect combines Clip with Round Rect
clipRect combines Clip with Rect
clipRegion combines Clip with Region
concat multiplies Matrix by Matrix
discard makes Canvas contents undefined
drawAnnotation associates a Rect with a key-value pair
drawArc draws Arc using Clip, Matrix, and Paint
drawAtlas draws sprites using Clip, Matrix, and Paint
drawBitmap draws Bitmap at (x, y) position
drawBitmapLattice draws proportionally stretched Bitmap
drawBitmapNine draws Nine Patch Bitmap
drawBitmapRect draws Bitmap, source Rect to destination Rect
drawCircle draws Circle using Clip, Matrix, and Paint
drawColor fills Clip with Color and Blend Mode
drawDRRect draws double Round Rect stroked or filled
drawDrawable draws Drawable, encapsulated drawing commands
drawIRect draws IRect using Clip, Matrix, and Paint
drawImage draws Image at (x, y) position
drawImageLattice draws proportionally stretched Image
drawImageNine draws Nine Patch Image
drawImageRect draws Image, source Rect to destination Rect
drawLine draws line segment between two points
drawOval draws Oval using Clip, Matrix, and Paint
drawPaint fills Clip with Paint
drawPatch draws Coons Patch
drawPath draws Path using Clip, Matrix, and Paint
drawPicture draws Picture using Clip and Matrix
drawPoint draws point at (x, y) position
drawPoints draws array as points, lines, polygon
drawPosText draws text at array of (x, y) positions
drawPosTextH draws text at x positions with common baseline
drawRRect draws Round Rect using Clip, Matrix, and Paint
drawRect draws Rect using Clip, Matrix, and Paint
drawRegion draws Region using Clip, Matrix, and Paint
drawRoundRect draws Round Rect using Clip, Matrix, and Paint
drawString draws null terminated string at (x, y) using font advance
drawText draws text at (x, y), using font advance
drawTextBlob draws text with arrays of positions and Paint
drawTextOnPath draws text following Path contour
drawTextOnPathHV draws text following Path with offsets
drawTextRSXform draws text with array of RSXform
drawVertices draws Vertices, a triangle mesh
flush triggers execution of all pending draw operations
getBaseLayerSize returns size of base Layer in global coordinates
getDeviceClipBounds returns IRect bounds of Clip
getGrContext returns GPU Context of the GPU Surface
getLocalClipBounds returns Clip bounds in source coordinates
getMetaData associates additional data with the canvas
getProps copies Surface Properties if available
getSaveCount returns depth of stack containing Clip and Matrix
getTotalMatrix returns Matrix
imageInfo returns Image Info for Canvas
isClipEmpty returns if Clip is empty
isClipRect returns if Clip is Rect and not empty
makeSurface creates Surface matching SkImageInfo and SkSurfaceProps
peekPixels returns if Canvas has direct access to its pixels
quickReject returns if Rect is outside Clip
readPixels copies and converts rectangle of pixels from Canvas
resetMatrix resets Matrix to identity
restore restores changes to Clip and Matrix, pops save stack
restoreToCount restores changes to Clip and Matrix to given depth
rotate rotates Matrix
save saves Clip and Matrix on stack
saveLayer saves Clip and Matrix on stack; creates Layer
saveLayerAlpha saves Clip and Matrix on stack; creates Layer; sets opacity
saveLayerPreserveLCDTextRequests saves Clip and Matrix on stack; creates Layer for LCD text
scale scales Matrix
setMatrix sets Matrix
skew skews Matrix
translate translates Matrix
writePixels copies and converts rectangle of pixels to Canvas
## MakeRasterDirect 
static std::unique_ptr<SkCanvas> MakeRasterDirect(const SkImageInfo& info, void* pixels,
                                                  size_t rowBytes,
                                                  const SkSurfaceProps* props = nullptr)
Allocates raster Canvas that will draw directly into pixels. Canvas is returned if all parameters are valid. Valid parameters include: info dimensions are zero or positive; info contains Color Type and Alpha Type supported by Raster Surface; pixels is not nullptr; rowBytes is zero or large enough to contain info width pixels of Color Type. Pass zero for rowBytes to compute rowBytes from info width and size of pixel. If rowBytes is greater than zero, it must be equal to or greater than info width times bytes required for Color Type. Pixel buffer size should be info height times computed rowBytes. Pixels are not initialized. To access pixels after drawing, call flush or peekPixels. ### Parameters
info width, height, Color Type, Alpha Type, Color Space, of Raster Surface; width, or height, or both, may be zero
pixels pointer to destination pixels buffer
rowBytes interval from one Surface row to the next, or zero
props LCD striping orientation and setting for device independent fonts; may be nullptr
### Return Value Canvas if all parameters are valid; otherwise, nullptr ### Example
Allocates a three by three bitmap, clears it to white, and draws a black pixel in the center.
#### Example Output ~~~~ --- -x- --- ~~~~
### See Also MakeRasterDirectN32 SkSurface::MakeRasterDirect --- ## MakeRasterDirectN32 
static std::unique_ptr<SkCanvas> MakeRasterDirectN32(int width, int height, SkPMColor* pixels,
                                                     size_t rowBytes)
Allocates raster Canvas specified by inline image specification. Subsequent Canvas calls draw into pixels. Color Type is set to kN32_SkColorType. Alpha Type is set to kPremul_SkAlphaType. To access pixels after drawing, call flush or peekPixels. Canvas is returned if all parameters are valid. Valid parameters include: width and height are zero or positive; pixels is not nullptr; rowBytes is zero or large enough to contain width pixels of kN32_SkColorType. Pass zero for rowBytes to compute rowBytes from width and size of pixel. If rowBytes is greater than zero, it must be equal to or greater than width times bytes required for Color Type. Pixel buffer size should be height times rowBytes. ### Parameters
width pixel column count on Raster Surface created; must be zero or greater
height pixel row count on Raster Surface created; must be zero or greater
pixels pointer to destination pixels buffer; buffer size should be height times rowBytes
rowBytes interval from one Surface row to the next, or zero
### Return Value Canvas if all parameters are valid; otherwise, nullptr ### Example
Allocates a three by three bitmap, clears it to white, and draws a black pixel in the center.
#### Example Output ~~~~ --- -x- --- ~~~~
### See Also MakeRasterDirect SkSurface::MakeRasterDirect SkImageInfo::MakeN32Premul[2] --- ## SkCanvas 
SkCanvas()
Creates an empty Canvas with no backing device or pixels, with a width and height of zero. ### Return Value empty Canvas ### Example
Passes a placeholder to a function that requires one.
#### Example Output ~~~~ paint draws text left to right paint draws text top to bottom paint draws text top to bottom ~~~~
### See Also MakeRasterDirect SkRasterHandleAllocator::MakeCanvas SkSurface::getCanvas SkCreateColorSpaceXformCanvas --- ## SkCanvas 
SkCanvas(int width, int height, const SkSurfaceProps* props = nullptr)
Creates Canvas of the specified dimensions without a Surface. Used by Subclasses with custom implementations for draw member functions. If props equals nullptr, Surface Properties are created with Surface Properties Legacy Font Host settings, which choose the pixel striping direction and order. Since a platform may dynamically change its direction when the device is rotated, and since a platform may have multiple monitors with different characteristics, it is best not to rely on this legacy behavior. ### Parameters
width zero or greater
height zero or greater
props LCD striping orientation and setting for device independent fonts; may be nullptr
### Return Value Canvas placeholder with dimensions ### Example
#### Example Output ~~~~ canvas is empty ~~~~
### See Also MakeRasterDirect SkSurfaceProps SkPixelGeometry SkCreateColorSpaceXformCanvas --- ## SkCanvas 
explicit SkCanvas(sk sp<SkBaseDevice> device)
Deprecated. soon --- ## SkCanvas 
explicit SkCanvas(const SkBitmap& bitmap)
Constructs a canvas that draws into bitmap. Sets SkSurfaceProps::kLegacyFontHost InitType in constructed Surface. Bitmap is copied so that subsequently editing bitmap will not affect constructed Canvas. May be deprecated in the future. ### Parameters
bitmap width, height, Color Type, Alpha Type, and pixel storage of Raster Surface
### Return Value Canvas that can be used to draw into bitmap ### Example
The actual output depends on the installed fonts.
#### Example Output ~~~~ ----- ---x- ---x- ---x- ---x- ---x- ---x- ----- ---x- ---x- ----- ~~~~
### See Also MakeRasterDirect SkRasterHandleAllocator::MakeCanvas SkSurface::getCanvas SkCreateColorSpaceXformCanvas --- ## Enum SkCanvas::ColorBehavior 
    enum class ColorBehavior {
        kLegacy,
    };
### Constants
Const Value Description
SkCanvas::ColorBehavior::kLegacy 0 Is a placeholder to allow specialized constructor; has no meaning.
## SkCanvas 
SkCanvas(const SkBitmap& bitmap, ColorBehavior behavior)
For use by Android framework only. ### Parameters
bitmap specifies a bitmap for the canvas to draw into
behavior specializes this constructor; value is unused
### Return Value Canvas that can be used to draw into bitmap --- ## SkCanvas 
SkCanvas(const SkBitmap& bitmap, const SkSurfaceProps& props)
Constructs a canvas that draws into bitmap. Use props to match the device characteristics, like LCD striping. bitmap is copied so that subsequently editing bitmap will not affect constructed Canvas. ### Parameters
bitmap width, height, Color Type, Alpha Type, and pixel storage of Raster Surface
props order and orientation of RGB striping; and whether to use device independent fonts
### Return Value Canvas that can be used to draw into bitmap ### Example
The actual output depends on the installed fonts.
#### Example Output ~~~~ ----- ---x- ---x- ---x- ---x- ---x- ---x- ----- ---x- ---x- ----- ~~~~
### See Also MakeRasterDirect SkRasterHandleAllocator::MakeCanvas SkSurface::getCanvas SkCreateColorSpaceXformCanvas --- ## ~SkCanvas 
virtual ~SkCanvas()
Draws saved Layers, if any. Frees up resources used by Canvas. ### Example
Canvas Layer draws into bitmap. saveLayerAlpha sets up an additional drawing surface that blends with the bitmap. When Layer goes out of scope, Layer Destructor is called. The saved Layer is restored, drawing transparent letters.
### See Also State Stack --- ## Property
Topic Description
getBaseLayerSize returns size of base Layer in global coordinates
getGrContext returns GPU Context of the GPU Surface
getMetaData associates additional data with the canvas
getProps copies Surface Properties if available
imageInfo returns Image Info for Canvas
isClipEmpty returns if Clip is empty
isClipRect returns if Clip is Rect and not empty
## getMetaData 
SkMetaData& getMetaData()
Returns storage to associate additional data with the canvas. The storage is freed when Canvas is deleted. ### Return Value storage that can be read from and written to ### Example
#### Example Output ~~~~ before: (null) during: Hello! after: (null) ~~~~
### See Also SkMetaData --- ## imageInfo 
SkImageInfo imageInfo() const
Returns Image Info for Canvas. If Canvas is not associated with Raster Surface or GPU Surface, returned Color Type is set to kUnknown_SkColorType. ### Return Value dimensions and Color Type of Canvas ### Example
#### Example Output ~~~~ emptyInfo == canvasInfo ~~~~
### See Also SkImageInfo MakeRasterDirect makeSurface --- ## getProps 
bool getProps(SkSurfaceProps* props) const
Copies Surface Properties, if Canvas is associated with Raster Surface or GPU Surface, and returns true. Otherwise, returns false and leave props unchanged. ### Parameters
props storage for writable SkSurfaceProps
### Return Value true if Surface Properties was copied ### Example
#### Example Output ~~~~ isRGB:0 isRGB:1 ~~~~
### See Also SkSurfaceProps makeSurface --- ## Utility
Topic Description
accessTopLayerPixels returns writable pixel access if available
accessTopRasterHandle returns context that tracks Clip and Matrix
discard makes Canvas contents undefined
flush triggers execution of all pending draw operations
## flush 
void flush()
Triggers the immediate execution of all pending draw operations. If Canvas is associated with GPU Surface, resolves all pending GPU operations. If Canvas is associated with Raster Surface, has no effect; raster draw operations are never deferred. ### See Also peekPixels SkSurface::flush() GrContext::flush() SkSurface::prepareForExternalIO GrContext::abandonContext() --- ## getBaseLayerSize 
virtual SkISize getBaseLayerSize() const
Gets the size of the base or root Layer in global canvas coordinates. The origin of the base Layer is always (0,0). The area available for drawing may be smaller (due to clipping or saveLayer). ### Return Value integral width and height of base Layer ### Example
#### Example Output ~~~~ clip=10,30 size=20,30 ~~~~
### See Also getDeviceClipBounds[2] --- ## makeSurface 
sk sp<SkSurface> makeSurface(const SkImageInfo& info, const SkSurfaceProps* props = nullptr)
Creates Surface matching info and props, and associates it with Canvas. Returns nullptr if no match found. If props is nullptr, matches Surface Properties in Canvas. If props is nullptr and Canvas does not have Surface Properties, creates Surface with default Surface Properties. ### Parameters
info width, height, Color Type, Alpha Type, and Color Space
props Surface Properties to match; may be nullptr to match Canvas
### Return Value Surface matching info and props, or nullptr if no match is available ### Example
#### Example Output ~~~~ compatible != nullptr size = 3, 4 ~~~~
### See Also SkSurface SkSurface::makeSurface SkImageInfo SkSurfaceProps --- ## getGrContext 
virtual GrContext* getGrContext()
Returns GPU Context of the GPU Surface associated with Canvas. ### Return Value GPU Context, if available; nullptr otherwise ### Example
### See Also GrContext --- ## accessTopLayerPixels 
void* accessTopLayerPixels(SkImageInfo* info, size_t* rowBytes, SkIPoint* origin = nullptr)
Returns the pixel base address, Image Info, rowBytes, and origin if the pixels can be read directly. The returned address is only valid while Canvas is in scope and unchanged. Any Canvas call or Surface call may invalidate the returned address and other returned values. If pixels are inaccessible, info, rowBytes, and origin are unchanged. ### Parameters
info storage for writable pixels' Image Info; may be nullptr
rowBytes storage for writable pixels' row bytes; may be nullptr
origin storage for Canvas top Layer origin, its top-left corner; may be nullptr
### Return Value address of pixels, or nullptr if inaccessible ### Example
### Example
Draws "" on the device. Then draws "" in Layer, and reads Layer to add a large dotted "". Finally blends Layer with the device. The Layer and blended result appear on the CPU and GPU but the large dotted "" appear only on the CPU.
### See Also SkImageInfo SkPixmap --- ## accessTopRasterHandle 
SkRasterHandleAllocator::Handle accessTopRasterHandle() const
Returns custom context that tracks the Matrix and Clip. Use Raster Handle Allocator to blend Skia drawing with custom drawing, typically performed by the host platform user interface. The custom context returned is generated by SkRasterHandleAllocator::MakeCanvas, which creates a custom canvas with raster storage for the drawing destination. ### Return Value context of custom allocation ### Example
#### Example Output ~~~~ context = skia ~~~~
### See Also SkRasterHandleAllocator --- ## Pixels
Topic Description
peekPixels returns if Canvas has direct access to its pixels
readPixels copies and converts rectangle of pixels from Canvas
readPixels(const SkImageInfo& dstInfo, void* dstPixels, size t dstRowBytes, int srcX, int srcY)
readPixels(const SkPixmap& pixmap, int srcX, int srcY)
readPixels(const SkBitmap& bitmap, int srcX, int srcY)
writePixels copies and converts rectangle of pixels to Canvas
writePixels(const SkImageInfo& info, const void* pixels, size t rowBytes, int x, int y)
writePixels(const SkBitmap& bitmap, int x, int y)
## peekPixels 
bool peekPixels(SkPixmap* pixmap)
Returns true if Canvas has direct access to its pixels. Pixels are readable when Device is raster. Pixels are not readable when Canvas is returned from GPU Surface, returned by SkDocument::beginPage, returned by SkPictureRecorder::beginRecording, or Canvas is the base of a utility class like SkDebugCanvas. pixmap is valid only while Canvas is in scope and unchanged. Any Canvas or Surface call may invalidate the pixmap values. ### Parameters
pixmap storage for pixel state if pixels are readable; otherwise, ignored
### Return Value true if Canvas has direct access to pixels ### Example
#### Example Output ~~~~ width=256 height=256 ~~~~
### See Also readPixels[2][3] SkBitmap::peekPixels SkImage::peekPixels SkSurface::peekPixels --- ## readPixels 
bool readPixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dstRowBytes, int srcX, int srcY)
Copies Rect of pixels from Canvas into dstPixels. Matrix and Clip are ignored. Source Rect corners are (srcX, srcY) and (imageInfo.width(), imageInfo.height()). Destination Rect corners are (0, 0) and (dstInfo.width(), dstInfo.height()). Copies each readable pixel intersecting both rectangles, without scaling, converting to dstInfo.colorType() and dstInfo.alphaType() if required. Pixels are readable when Device is raster, or backed by a GPU. Pixels are not readable when SkCanvas is returned by SkDocument::beginPage, returned by SkPictureRecorder::beginRecording, or Canvas is the base of a utility class like SkDebugCanvas. The destination pixel storage must be allocated by the caller. Pixel values are converted only if Color Type and Alpha Type do not match. Only pixels within both source and destination rectangles are copied. dstPixels contents outside Rect intersection are unchanged. Pass negative values for srcX or srcY to offset pixels across or down destination. Does not copy, and returns false if:
Source and destination rectangles do not intersect.
Canvas pixels could not be converted to dstInfo.colorType() or dstInfo.alphaType().
Canvas pixels are not readable; for instance, Canvas is document-based.
dstRowBytes is too small to contain one row of pixels.
### Parameters
dstInfo width, height, Color Type, and Alpha Type of dstPixels
dstPixels storage for pixels; dstInfo.height() times dstRowBytes, or larger
dstRowBytes size of one destination row; dstInfo.width() times pixel size, or larger
srcX offset into readable pixels on x-axis; may be negative
srcY offset into readable pixels on y-axis; may be negative
### Return Value true if pixels were copied ### Example
A black circle drawn on a blue background provides an image to copy. readPixels copies one quarter of the canvas into each of the four corners. The copied quarter circles overdraw the original circle.
### Example
Canvas returned by Raster Surface has Premultiplied pixel values. clear takes Unpremultiplied input with Color Alpha equal 0x80 and RGB equal 0x55, 0xAA, 0xFF. RGB is multiplied by Color Alpha to generate Premultiplied value 0x802B5580. readPixels converts pixel back to Unpremultiplied value 0x8056A9FF, introducing error.
#### Example Output ~~~~ pixel = 802b5580 pixel = 8056a9ff ~~~~
### See Also peekPixels writePixels[2] drawBitmap drawImage[2] SkBitmap::readPixels[2][3] SkPixmap::readPixels[2][3][4] SkImage::readPixels[2] SkSurface::readPixels[2][3] --- 
bool readPixels(const SkPixmap& pixmap, int srcX, int srcY)
Copies Rect of pixels from Canvas into pixmap. Matrix and Clip are ignored. Source Rect corners are (srcX, srcY) and (imageInfo.width(), imageInfo.height()). Destination Rect corners are (0, 0) and (pixmap.width(), pixmap.height()). Copies each readable pixel intersecting both rectangles, without scaling, converting to pixmap.colorType() and pixmap.alphaType() if required. Pixels are readable when Device is raster, or backed by a GPU. Pixels are not readable when SkCanvas is returned by SkDocument::beginPage, returned by SkPictureRecorder::beginRecording, or Canvas is the base of a utility class like SkDebugCanvas. Caller must allocate pixel storage in pixmap if needed. Pixel values are converted only if Color Type and Alpha Type do not match. Only pixels within both source and destination Rects are copied. pixmap pixels contents outside Rect intersection are unchanged. Pass negative values for srcX or srcY to offset pixels across or down pixmap. Does not copy, and returns false if:
Source and destination rectangles do not intersect.
Canvas pixels could not be converted to pixmap.colorType() or pixmap.alphaType().
Canvas pixels are not readable; for instance, Canvas is document-based.
Pixmap pixels could not be allocated.
pixmap.rowBytes() is too small to contain one row of pixels.
### Parameters
pixmap storage for pixels copied from Canvas
srcX offset into readable pixels on x-axis; may be negative
srcY offset into readable pixels on y-axis; may be negative
### Return Value true if pixels were copied ### Example
clear takes Unpremultiplied input with Color Alpha equal 0x80 and RGB equal 0x55, 0xAA, 0xFF. RGB is multiplied by Color Alpha to generate Premultiplied value 0x802B5580.
#### Example Output ~~~~ pixel = 802b5580 ~~~~
### See Also peekPixels writePixels[2] drawBitmap drawImage[2] SkBitmap::readPixels[2][3] SkPixmap::readPixels[2][3][4] SkImage::readPixels[2] SkSurface::readPixels[2][3] --- 
bool readPixels(const SkBitmap& bitmap, int srcX, int srcY)
Copies Rect of pixels from Canvas into bitmap. Matrix and Clip are ignored. Source Rect corners are (srcX, srcY) and (imageInfo.width(), imageInfo.height()). Destination Rect corners are (0, 0) and (bitmap.width(), bitmap.height()). Copies each readable pixel intersecting both rectangles, without scaling, converting to bitmap.colorType() and bitmap.alphaType() if required. Pixels are readable when Device is raster, or backed by a GPU. Pixels are not readable when SkCanvas is returned by SkDocument::beginPage, returned by SkPictureRecorder::beginRecording, or Canvas is the base of a utility class like SkDebugCanvas. Caller must allocate pixel storage in bitmap if needed. Bitmap values are converted only if Color Type and Alpha Type do not match. Only pixels within both source and destination rectangles are copied. Bitmap pixels outside Rect intersection are unchanged. Pass negative values for srcX or srcY to offset pixels across or down bitmap. Does not copy, and returns false if:
Source and destination rectangles do not intersect.
Canvas pixels could not be converted to bitmap.colorType() or bitmap.alphaType().
Canvas pixels are not readable; for instance, Canvas is document-based.
bitmap pixels could not be allocated.
bitmap.rowBytes() is too small to contain one row of pixels.
### Parameters
bitmap storage for pixels copied from Canvas
srcX offset into readable pixels on x-axis; may be negative
srcY offset into readable pixels on y-axis; may be negative
### Return Value true if pixels were copied ### Example
clear takes Unpremultiplied input with Color Alpha equal 0x80 and RGB equal 0x55, 0xAA, 0xFF. RGB is multiplied by Color Alpha to generate Premultiplied value 0x802B5580.
#### Example Output ~~~~ pixel = 802b5580 ~~~~
### See Also peekPixels writePixels[2] drawBitmap drawImage[2] SkBitmap::readPixels[2][3] SkPixmap::readPixels[2][3][4] SkImage::readPixels[2] SkSurface::readPixels[2][3] --- ## writePixels 
bool writePixels(const SkImageInfo& info, const void* pixels, size_t rowBytes, int x, int y)
Copies Rect from pixels to Canvas. Matrix and Clip are ignored. Source Rect corners are (0, 0) and (info.width(), info.height()). Destination Rect corners are (x, y) and (imageInfo.width(), imageInfo.height()). Copies each readable pixel intersecting both rectangles, without scaling, converting to imageInfo.colorType() and imageInfo.alphaType() if required. Pixels are writable when Device is raster, or backed by a GPU. Pixels are not writable when SkCanvas is returned by SkDocument::beginPage, returned by SkPictureRecorder::beginRecording, or Canvas is the base of a utility class like SkDebugCanvas. Pixel values are converted only if Color Type and Alpha Type do not match. Only pixels within both source and destination rectangles are copied. Canvas pixels outside Rect intersection are unchanged. Pass negative values for x or y to offset pixels to the left or above Canvas pixels. Does not copy, and returns false if:
Source and destination rectangles do not intersect.
pixels could not be converted to Canvas imageInfo.colorType() or imageInfo.alphaType().
Canvas pixels are not writable; for instance, Canvas is document-based.
rowBytes is too small to contain one row of pixels.
### Parameters
info width, height, Color Type, and Alpha Type of pixels
pixels pixels to copy, of size info.height() times rowBytes, or larger
rowBytes size of one row of pixels; info.width() times pixel size, or larger
x offset into Canvas writable pixels on x-axis; may be negative
y offset into Canvas writable pixels on y-axis; may be negative
### Return Value true if pixels were written to Canvas ### Example
### See Also readPixels[2][3] drawBitmap drawImage[2] SkBitmap::writePixels[2] --- 
bool writePixels(const SkBitmap& bitmap, int x, int y)
Copies Rect from pixels to Canvas. Matrix and Clip are ignored. Source Rect corners are (0, 0) and (bitmap.width(), bitmap.height()). Destination Rect corners are (x, y) and (imageInfo.width(), imageInfo.height()). Copies each readable pixel intersecting both rectangles, without scaling, converting to imageInfo.colorType() and imageInfo.alphaType() if required. Pixels are writable when Device is raster, or backed by a GPU. Pixels are not writable when SkCanvas is returned by SkDocument::beginPage, returned by SkPictureRecorder::beginRecording, or Canvas is the base of a utility class like SkDebugCanvas. Pixel values are converted only if Color Type and Alpha Type do not match. Only pixels within both source and destination rectangles are copied. Canvas pixels outside Rect intersection are unchanged. Pass negative values for x or y to offset pixels to the left or above Canvas pixels. Does not copy, and returns false if:
Source and destination rectangles do not intersect.
bitmap does not have allocated pixels.
bitmap pixels could not be converted to Canvas imageInfo.colorType() or imageInfo.alphaType().
Canvas pixels are not writable; for instance, Canvas is document based.
bitmap pixels are inaccessible; for instance, bitmap wraps a texture.
### Parameters
bitmap contains pixels copied to Canvas
x offset into Canvas writable pixels in x; may be negative
y offset into Canvas writable pixels in y; may be negative
### Return Value true if pixels were written to Canvas ### Example
### See Also readPixels[2][3] drawBitmap drawImage[2] SkBitmap::writePixels[2] --- ## State Stack Canvas maintains a stack of state that allows hierarchical drawing, commonly used to implement windows and views. The initial state has an identity matrix and and an infinite clip. Even with a wide-open clip, drawing is constrained by the bounds of the Canvas Surface or Device. Canvas savable state consists of Clip and Matrix. Clip describes the area that may be drawn to. Matrix transforms the geometry. save, saveLayer, saveLayerPreserveLCDTextRequests, and saveLayerAlpha save state and return the depth of the stack. restore, restoreToCount, and ~SkCanvas() revert state to its value when saved. Each state on the stack intersects Clip with the previous Clip, and concatenates Matrix with the previous Matrix. The intersected Clip makes the drawing area the same or smaller; the concatenated Matrix may move the origin and potentially scale or rotate the coordinate space. Canvas does not require balancing the state stack but it is a good idea to do so. Calling save without restore will eventually cause Skia to fail; mismatched save and restore create hard to find bugs. It is not possible to use state to draw outside of the clip defined by the previous state. ### Example
Draw to ever smaller clips; then restore drawing to full canvas. Note that the second clipRect is not permitted to enlarge Clip.
Each Clip uses the current Matrix for its coordinates. ### Example
While clipRect is given the same rectangle twice, Matrix makes the second clipRect draw at half the size of the first.
### See Also save saveLayer[2][3] saveLayerPreserveLCDTextRequests saveLayerAlpha restore restoreToCount ## save 
int save()
Saves Matrix and Clip. Calling restore discards changes to Matrix and Clip, restoring the Matrix and Clip to their state when save was called. Matrix may be changed by translate, scale, rotate, skew, concat, setMatrix, and resetMatrix. Clip may be changed by clipRect, clipRRect, clipPath, clipRegion. Saved Canvas state is put on a stack; multiple calls to save should be balance by an equal number of calls to restore. Call restoreToCount with result to restore this and subsequent saves. ### Return Value depth of saved stack ### Example
The black square is translated 50 pixels down and to the right. Restoring Canvas state removes translate from Canvas stack; the red square is not translated, and is drawn at the origin.
### See Also saveLayer[2][3] saveLayerPreserveLCDTextRequests saveLayerAlpha restore restoreToCount --- ## restore 
void restore()
Removes changes to Matrix and Clip since Canvas state was last saved. The state is removed from the stack. Does nothing if the stack is empty. ### Example
### See Also save saveLayer[2][3] saveLayerPreserveLCDTextRequests saveLayerAlpha restoreToCount --- ## getSaveCount 
int getSaveCount() const
Returns the number of saved states, each containing: Matrix and Clip. Equals the number of save calls less the number of restore calls plus one. The save count of a new canvas is one. ### Return Value depth of save state stack ### Example
#### Example Output ~~~~ depth = 1 depth = 2 depth = 1 ~~~~
### See Also save restore restoreToCount --- ## restoreToCount 
void restoreToCount(int saveCount)
Restores state to Matrix and Clip values when save, saveLayer, saveLayerPreserveLCDTextRequests, or saveLayerAlpha returned saveCount. Does nothing if saveCount is greater than state stack count. Restores state to initial values if saveCount is less than or equal to one. ### Parameters
saveCount depth of state stack to restore
### Example
#### Example Output ~~~~ depth = 1 depth = 3 depth = 1 ~~~~
### See Also restore getSaveCount save --- ## Layer Layer allocates a temporary Bitmap to draw into. When the drawing is complete, the Bitmap is drawn into the Canvas. Layer is saved in a stack along with other saved state. When state with a Layer is restored, the Bitmap is drawn into the previous Layer. Layer may be initialized with the contents of the previous Layer. When Layer is restored, its Bitmap can be modified by Paint passed to Layer to apply Color Alpha, Color Filter, Image Filter, and Blend Mode. ## saveLayer 
int saveLayer(const SkRect* bounds, const SkPaint* paint)
Saves Matrix and Clip, and allocates a Bitmap for subsequent drawing. Calling restore discards changes to Matrix and Clip, and draws the Bitmap. Matrix may be changed by translate, scale, rotate, skew, concat, setMatrix, and resetMatrix. Clip may be changed by clipRect, clipRRect, clipPath, clipRegion. Rect bounds suggests but does not define the Bitmap size. To clip drawing to a specific rectangle, use clipRect. Optional Paint paint applies Color Alpha, Color Filter, Image Filter, and Blend Mode when restore is called. Call restoreToCount with returned value to restore this and subsequent saves. ### Parameters
bounds hint to limit the size of the Layer; may be nullptr
paint graphics state for Layer; may be nullptr
### Return Value depth of saved stack ### Example
Rectangles are blurred by Image Filter when restore draws Layer to main Canvas.
### See Also save restore saveLayer[2][3] saveLayerPreserveLCDTextRequests saveLayerAlpha SaveLayerRec --- 
int saveLayer(const SkRect& bounds, const SkPaint* paint)
Saves Matrix and Clip, and allocates a Bitmap for subsequent drawing. Calling restore discards changes to Matrix and Clip, and draws the Bitmap. Matrix may be changed by translate, scale, rotate, skew, concat, setMatrix, and resetMatrix. Clip may be changed by clipRect, clipRRect, clipPath, clipRegion. Rect bounds suggests but does not define the Layer size. To clip drawing to a specific rectangle, use clipRect. Optional Paint paint applies Color Alpha, Color Filter, Image Filter, and Blend Mode when restore is called. Call restoreToCount with returned value to restore this and subsequent saves. ### Parameters
bounds hint to limit the size of Layer; may be nullptr
paint graphics state for Layer; may be nullptr
### Return Value depth of saved stack ### Example
Rectangles are blurred by Image Filter when restore draws Layer to main Canvas. The red rectangle is clipped; it does not fully fit on Layer. Image Filter blurs past edge of Layer so red rectangle is blurred on all sides.
### See Also save restore saveLayerPreserveLCDTextRequests saveLayerAlpha SaveLayerRec --- ## saveLayerPreserveLCDTextRequests 
int saveLayerPreserveLCDTextRequests(const SkRect* bounds, const SkPaint* paint)
Saves Matrix and Clip, and allocates a Bitmap for subsequent drawing. LCD Text is preserved when the Layer is drawn to the prior Layer. Calling restore discards changes to Matrix and Clip, and draws Layer. Matrix may be changed by translate, scale, rotate, skew, concat, setMatrix, and resetMatrix. Clip may be changed by clipRect, clipRRect, clipPath, clipRegion. Rect bounds suggests but does not define the Layer size. To clip drawing to a specific rectangle, use clipRect. Optional Paint paint applies Color Alpha, Color Filter, Image Filter, and Blend Mode when restore is called. Call restoreToCount with returned value to restore this and subsequent saves. Draw text on an opaque background so that LCD Text blends correctly with the prior Layer. LCD Text drawn on a background with transparency may result in incorrect blending. ### Parameters
bounds hint to limit the size of Layer; may be nullptr
paint graphics state for Layer; may be nullptr
### Return Value depth of saved stack ### Example
### See Also save restore saveLayer[2][3] saveLayerAlpha SaveLayerRec --- ## saveLayerAlpha 
int saveLayerAlpha(const SkRect* bounds, U8CPU alpha)
Saves Matrix and Clip, and allocates Bitmap for subsequent drawing. Calling restore discards changes to Matrix and Clip, and blends Layer with alpha opacity onto prior Layer. Matrix may be changed by translate, scale, rotate, skew, concat, setMatrix, and resetMatrix. Clip may be changed by clipRect, clipRRect, clipPath, clipRegion. Rect bounds suggests but does not define Layer size. To clip drawing to a specific rectangle, use clipRect. alpha of zero is fully transparent, 255 is fully opaque. Call restoreToCount with returned value to restore this and subsequent saves. ### Parameters
bounds hint to limit the size of Layer; may be nullptr
alpha opacity of Layer
### Return Value depth of saved stack ### Example
### See Also save restore saveLayer[2][3] saveLayerPreserveLCDTextRequests SaveLayerRec --- ## Enum SkCanvas::SaveLayerFlagsSet 
    enum SaveLayerFlagsSet {
        kPreserveLCDText SaveLayerFlag = 1 << 1,
        kInitWithPrevious SaveLayerFlag = 1 << 2,
        kMaskAgainstCoverage EXPERIMENTAL DONT USE SaveLayerFlag = 1 << 3,
        kDontClipToLayer Legacy SaveLayerFlag = kDontClipToLayer_PrivateSaveLayerFlag,
    };

    typedef uint32_t SaveLayerFlags;
## Typedef SkCanvas::SaveLayerFlags SaveLayerFlags provides options that may be used in any combination in SaveLayerRec, defining how Layer allocated by saveLayer operates. It may be set to zero, kPreserveLCDText SaveLayerFlag, kInitWithPrevious SaveLayerFlag, or both flags. ### Constants
Const Value Description
SkCanvas::kPreserveLCDText_SaveLayerFlag 2 Creates Layer for LCD text. Flag is ignored if Layer Paint contains Image Filter or Color Filter.
SkCanvas::kInitWithPrevious_SaveLayerFlag 4 Initializes Layer with the contents of the previous Layer.
SkCanvas::kMaskAgainstCoverage_EXPERIMENTAL_DONT_USE_SaveLayerFlag 8 Experimental. do not use
SkCanvas::kDontClipToLayer_Legacy_SaveLayerFlag 0x80000000 Deprecated. soon
### Example
Canvas Layer captures red and blue circles scaled up by four. scalePaint blends Layer back with transparency.
### See Also save restore saveLayer[2][3] saveLayerPreserveLCDTextRequests saveLayerAlpha SaveLayerRec ## Layer SaveLayerRec # Struct SkCanvas::SaveLayerRec 
    struct SaveLayerRec {
        SaveLayerRec*(...

        const SkRect*           fBounds;
        const SkPaint*          fPaint;
        const SkImageFilter*    fBackdrop;
        SaveLayerFlags          fSaveLayerFlags;
    };
SaveLayerRec contains the state used to create the Layer. ## Layer SaveLayerRec Overview
Topic Description
Constructors functions that construct SkCanvas::SaveLayerRec
Members member values
## Layer SaveLayerRec Member
Topic Description
### Members
Type Name Description
const SkRect* fBounds fBounds is used as a hint to limit the size of Layer; may be nullptr. fBounds suggests but does not define Layer size. To clip drawing to a specific rectangle, use clipRect.
const SkPaint* fPaint fPaint modifies how Layer overlays the prior Layer; may be nullptr. Color Alpha, Blend Mode, Color Filter, Draw Looper, Image Filter, and Mask Filter affect Layer draw.
const SkImageFilter* fBackdrop fBackdrop applies Image Filter to the prior Layer when copying to the Layer; may be nullptr. Use kInitWithPrevious SaveLayerFlag to copy the prior Layer without an Image Filter.
const SkImage* fClipMask restore clips Layer by the Color Alpha channel of fClipMask when Layer is copied to Device. fClipMask may be nullptr. .
const SkMatrix* fClipMatrix fClipMatrix transforms fClipMask before it clips Layer. If fClipMask describes a translucent gradient, it may be scaled and rotated without introducing artifacts. fClipMatrix may be nullptr.
SaveLayerFlags fSaveLayerFlags fSaveLayerFlags are used to create Layer without transparency, create Layer for LCD text, and to create Layer with the contents of the previous Layer.
### Example
Canvas Layer captures a red Anti Aliased circle and a blue Aliased circle scaled up by four. After drawing another red circle without scaling on top, the Layer is transferred to the main canvas.
## Layer SaveLayerRec Constructor
Topic Description
## SaveLayerRec 
SaveLayerRec()
Sets fBounds, fPaint, and fBackdrop to nullptr. Clears fSaveLayerFlags. ### Return Value empty SaveLayerRec ### Example
#### Example Output ~~~~ rec1 == rec2 ~~~~
### See Also save restore saveLayer[2][3] saveLayerPreserveLCDTextRequests saveLayerAlpha --- ## SaveLayerRec 
SaveLayerRec(const SkRect* bounds, const SkPaint* paint, SaveLayerFlags saveLayerFlags = 0)
Sets fBounds, fPaint, and fSaveLayerFlags; sets fBackdrop to nullptr. ### Parameters
bounds Layer dimensions; may be nullptr
paint applied to Layer when overlaying prior Layer; may be nullptr
saveLayerFlags SaveLayerRec options to modify Layer
### Return Value SaveLayerRec with empty backdrop ### Example
#### Example Output ~~~~ rec1 == rec2 ~~~~
### See Also save restore saveLayer[2][3] saveLayerPreserveLCDTextRequests saveLayerAlpha --- ## SaveLayerRec 
SaveLayerRec(const SkRect* bounds, const SkPaint* paint, const SkImageFilter* backdrop,
             SaveLayerFlags saveLayerFlags)
Sets fBounds, fPaint, fBackdrop, and fSaveLayerFlags. ### Parameters
bounds Layer dimensions; may be nullptr
paint applied to Layer when overlaying prior Layer; may be nullptr
backdrop prior Layer copied with Image Filter; may be nullptr
saveLayerFlags SaveLayerRec options to modify Layer
### Return Value SaveLayerRec fully specified ### Example
#### Example Output ~~~~ rec1 == rec2 ~~~~
### See Also save restore saveLayer[2][3] saveLayerPreserveLCDTextRequests saveLayerAlpha --- ## SaveLayerRec 
SaveLayerRec(const SkRect* bounds, const SkPaint* paint, const SkImageFilter* backdrop,
             const SkImage* clipMask, const SkMatrix* clipMatrix, SaveLayerFlags saveLayerFlags)
Experimental. not readySets fBounds, fPaint, fBackdrop, fClipMask, fClipMatrix, and fSaveLayerFlags. clipMatrix uses Color Alpha channel of image, transformed by clipMatrix, to clip Layer when drawn to Canvas. Implementation is not complete; has no effect if Device is GPU-backed. ### Parameters
bounds Layer dimensions; may be nullptr
paint graphics state applied to Layer when overlaying prior Layer; may be nullptr
backdrop prior Layer copied with Image Filter; may be nullptr
clipMask clip applied to Layer; may be nullptr
clipMatrix matrix applied to clipMask; may be nullptr to use identity matrix
saveLayerFlags SaveLayerRec options to modify Layer
### Return Value SaveLayerRec fully specified ### See Also save restore saveLayer[2][3] saveLayerPreserveLCDTextRequests saveLayerAlpha --- 
int saveLayer(const SaveLayerRec& layerRec)
Saves Matrix and Clip, and allocates Bitmap for subsequent drawing. Calling restore discards changes to Matrix and Clip, and blends Bitmap with Color Alpha opacity onto the prior Layer. Matrix may be changed by translate, scale, rotate, skew, concat, setMatrix, and resetMatrix. Clip may be changed by clipRect, clipRRect, clipPath, clipRegion. SaveLayerRec contains the state used to create the Layer. Call restoreToCount with returned value to restore this and subsequent saves. ### Parameters
layerRec Layer state
### Return Value depth of save state stack ### Example
The example draws an image, and saves it into a Layer with kInitWithPrevious SaveLayerFlag. Next it punches a hole in Layer and restore with SkBlendMode::kPlus. Where Layer was cleared, the original image will draw unchanged. Outside of the circle the mandrill is brightened.
### See Also save restore saveLayer[2][3] saveLayerPreserveLCDTextRequests saveLayerAlpha --- ## Matrix ## translate 
void translate(SkScalar dx, SkScalar dy)
Translates Matrix by dx along the x-axis and dy along the y-axis. Mathematically, replaces Matrix with a translation matrix Premultiplied with Matrix. This has the effect of moving the drawing by (dx, dy) before transforming the result with Matrix. ### Parameters
dx distance to translate in x
dy distance to translate in y
### Example
scale followed by translate produces different results from translate followed by scale. The blue stroke follows translate of (50, 50); a black fill follows scale of (2, 1/2.f). After restoring the clip, which resets Matrix, a red frame follows the same scale of (2, 1/2.f); a gray fill follows translate of (50, 50).
### See Also concat scale skew rotate[2] setMatrix --- ## scale 
void scale(SkScalar sx, SkScalar sy)
Scales Matrix by sx on the x-axis and sy on the y-axis. Mathematically, replaces Matrix with a scale matrix Premultiplied with Matrix. This has the effect of scaling the drawing by (sx, sy) before transforming the result with Matrix. ### Parameters
sx amount to scale in x
sy amount to scale in y
### Example
### See Also concat translate skew rotate[2] setMatrix --- ## rotate 
void rotate(SkScalar degrees)
Rotates Matrix by degrees. Positive degrees rotates clockwise. Mathematically, replaces Matrix with a rotation matrix Premultiplied with Matrix. This has the effect of rotating the drawing by degrees before transforming the result with Matrix. ### Parameters
degrees amount to rotate, in degrees
### Example
Draw clock hands at time 5:10. The hour hand and minute hand point up and are rotated clockwise.
### See Also concat translate skew scale setMatrix --- 
void rotate(SkScalar degrees, SkScalar px, SkScalar py)
Rotates Matrix by degrees about a point at (px, py). Positive degrees rotates clockwise. Mathematically, constructs a rotation matrix; Premultiplies the rotation matrix by a translation matrix; then replaces Matrix with the resulting matrix Premultiplied with Matrix. This has the effect of rotating the drawing about a given point before transforming the result with Matrix. ### Parameters
degrees amount to rotate, in degrees
px x-axis value of the point to rotate about
py y-axis value of the point to rotate about
### Example
### See Also concat translate skew scale setMatrix --- ## skew 
void skew(SkScalar sx, SkScalar sy)
Skews Matrix by sx on the x-axis and sy on the y-axis. A positive value of sx skews the drawing right as y-axis values increase; a positive value of sy skews the drawing down as x-axis values increase. Mathematically, replaces Matrix with a skew matrix Premultiplied with Matrix. This has the effect of skewing the drawing by (sx, sy) before transforming the result with Matrix. ### Parameters
sx amount to skew on x-axis
sy amount to skew on y-axis
### Example
Black text mimics an oblique text style by using a negative skew on x-axis that shifts the geometry to the right as the y-axis values decrease. Red text uses a positive skew on y-axis to shift the geometry down as the x-axis values increase. Blue text combines sx and sy skew to rotate and scale.
### See Also concat translate rotate[2] scale setMatrix --- ## concat 
void concat(const SkMatrix& matrix)
Replaces Matrix with matrix Premultiplied with existing Matrix. This has the effect of transforming the drawn geometry by matrix, before transforming the result with existing Matrix. ### Parameters
matrix matrix to Premultiply with existing Matrix
### Example
### See Also translate rotate[2] scale skew setMatrix --- ## setMatrix 
void setMatrix(const SkMatrix& matrix)
Replaces Matrix with matrix. Unlike concat, any prior matrix state is overwritten. ### Parameters
matrix matrix to copy, replacing existing Matrix
### Example
### See Also resetMatrix concat translate rotate[2] scale skew --- ## resetMatrix 
void resetMatrix()
Sets Matrix to the identity matrix. Any prior matrix state is overwritten. ### Example
### See Also setMatrix concat translate rotate[2] scale skew --- ## getTotalMatrix 
const SkMatrix& getTotalMatrix() const
Returns Matrix. This does not account for translation by Device or Surface. ### Return Value Matrix in Canvas ### Example
#### Example Output ~~~~ isIdentity true ~~~~
### See Also setMatrix resetMatrix concat --- ## Clip Clip is built from a stack of clipping paths. Each Path in the stack can be constructed from one or more Path Contour elements. The Path Contour may be composed of any number of Path Verb segments. Each Path Contour forms a closed area; Path Fill Type defines the area enclosed by Path Contour. Clip stack of Path elements successfully restrict the Path area. Each Path is transformed by Matrix, then intersected with or subtracted from the prior Clip to form the replacement Clip. Use SkClipOp::kDifference to subtract Path from Clip; use SkClipOp::kIntersect to intersect Path with Clip. A clipping Path may be Anti Aliased; if Path, after transformation, is composed of horizontal and vertical lines, clearing Anti Alias allows whole pixels to either be inside or outside the clip. The fastest drawing has a Aliased, rectangular clip. If clipping Path has Anti Alias set, clip may partially clip a pixel, requiring that drawing blend partially with the destination along the edge. A rotated rectangular Anti Aliased clip looks smoother but draws slower. Clip can combine with Rect and Round Rect primitives; like Path, these are transformed by Matrix before they are combined with Clip. Clip can combine with Region. Region is assumed to be in Device coordinates and is unaffected by Matrix. ### Example
Draw a red circle with an Aliased clip and an Anti Aliased clip. Use an image filter to zoom into the pixels drawn. The edge of the Aliased clip fully draws pixels in the red circle. The edge of the Anti Aliased clip partially draws pixels in the red circle.
## clipRect 
void clipRect(const SkRect& rect, SkClipOp op, bool doAntiAlias)
Replaces Clip with the intersection or difference of Clip and rect, with an Aliased or Anti Aliased clip edge. rect is transformed by Matrix before it is combined with Clip. ### Parameters
rect Rect to combine with Clip
op Clip Op to apply to Clip
doAntiAlias true if Clip is to be Anti Aliased
### Example
### See Also clipRRect[2][3] clipPath[2][3] clipRegion --- 
void clipRect(const SkRect& rect, SkClipOp op)
Replaces Clip with the intersection or difference of Clip and rect. Resulting Clip is Aliased; pixels are fully contained by the clip. rect is transformed by Matrix before it is combined with Clip. ### Parameters
rect Rect to combine with Clip
op Clip Op to apply to Clip
### Example
### See Also clipRRect[2][3] clipPath[2][3] clipRegion --- 
void clipRect(const SkRect& rect, bool doAntiAlias = false)
Replaces Clip with the intersection of Clip and rect. Resulting Clip is Aliased; pixels are fully contained by the clip. rect is transformed by Matrix before it is combined with Clip. ### Parameters
rect Rect to combine with Clip
doAntiAlias true if Clip is to be Anti Aliased
### Example
A circle drawn in pieces looks uniform when drawn Aliased. The same circle pieces blend with pixels more than once when Anti Aliased, visible as a thin pair of lines through the right circle.
### See Also clipRRect[2][3] clipPath[2][3] clipRegion --- ## androidFramework_setDeviceClipRestriction 
void androidFramework setDeviceClipRestriction(const SkIRect& rect)
Sets the maximum clip rectangle, which can be set by clipRect, clipRRect and clipPath and intersect the current clip with the specified rect. The maximum clip affects only future clipping operations; it is not retroactive. The clip restriction is not recorded in pictures. Pass an empty rect to disable maximum clip. ### Parameters # --- ## clipRRect 
void clipRRect(const SkRRect& rrect, SkClipOp op, bool doAntiAlias)
Replaces Clip with the intersection or difference of Clip and rrect, with an Aliased or Anti Aliased clip edge. rrect is transformed by Matrix before it is combined with Clip. ### Parameters
rect maximum allowed clip in device coordinates
rrect Round Rect to combine with Clip
op Clip Op to apply to Clip
doAntiAlias true if Clip is to be Anti Aliased
### Example
### See Also clipRect[2][3] clipPath[2][3] clipRegion --- 
void clipRRect(const SkRRect& rrect, SkClipOp op)
Replaces Clip with the intersection or difference of Clip and rrect. Resulting Clip is Aliased; pixels are fully contained by the clip. rrect is transformed by Matrix before it is combined with Clip. ### Parameters
rrect Round Rect to combine with Clip
op Clip Op to apply to Clip
### Example
### See Also clipRect[2][3] clipPath[2][3] clipRegion --- 
void clipRRect(const SkRRect& rrect, bool doAntiAlias = false)
Replaces Clip with the intersection of Clip and rrect, with an Aliased or Anti Aliased clip edge. rrect is transformed by Matrix before it is combined with Clip. ### Parameters
rrect Round Rect to combine with Clip
doAntiAlias true if Clip is to be Anti Aliased
### Example
### See Also clipRect[2][3] clipPath[2][3] clipRegion --- ## clipPath 
void clipPath(const SkPath& path, SkClipOp op, bool doAntiAlias)
Replaces Clip with the intersection or difference of Clip and path, with an Aliased or Anti Aliased clip edge. Path Fill Type determines if path describes the area inside or outside its contours; and if Path Contour overlaps itself or another Path Contour, whether the overlaps form part of the area. path is transformed by Matrix before it is combined with Clip. ### Parameters
path Path to combine with Clip
op Clip Op to apply to Clip
doAntiAlias true if Clip is to be Anti Aliased
### Example
Top figure uses SkPath::kInverseWinding FillType and SkClipOp::kDifference; area outside clip is subtracted from circle. Bottom figure uses SkPath::kWinding FillType and SkClipOp::kIntersect; area inside clip is intersected with circle.
### See Also clipRect[2][3] clipRRect[2][3] clipRegion --- 
void clipPath(const SkPath& path, SkClipOp op)
Replaces Clip with the intersection or difference of Clip and path. Resulting Clip is Aliased; pixels are fully contained by the clip. Path Fill Type determines if path describes the area inside or outside its contours; and if Path Contour overlaps itself or another Path Contour, whether the overlaps form part of the area. path is transformed by Matrix before it is combined with Clip. ### Parameters
path Path to combine with Clip
op Clip Op to apply to Clip
### Example
Overlapping Rects form a clip. When clip Path Fill Type is set to SkPath::kWinding FillType, the overlap is included. Set to SkPath::kEvenOdd FillType, the overlap is excluded and forms a hole.
### See Also clipRect[2][3] clipRRect[2][3] clipRegion --- 
void clipPath(const SkPath& path, bool doAntiAlias = false)
Replaces Clip with the intersection of Clip and path. Resulting Clip is Aliased; pixels are fully contained by the clip. Path Fill Type determines if path describes the area inside or outside its contours; and if Path Contour overlaps itself or another Path Contour, whether the overlaps form part of the area. path is transformed by Matrix before it is combined with Clip. ### Parameters
path Path to combine with Clip
doAntiAlias true if Clip is to be Anti Aliased
### Example
Clip loops over itself covering its center twice. When clip Path Fill Type is set to SkPath::kWinding FillType, the overlap is included. Set to SkPath::kEvenOdd FillType, the overlap is excluded and forms a hole.
### See Also clipRect[2][3] clipRRect[2][3] clipRegion --- ## setAllowSimplifyClip 
void setAllowSimplifyClip(bool allow)
Experimental. testingSet to simplify clip stack using PathOps. --- ## clipRegion 
void clipRegion(const SkRegion& deviceRgn, SkClipOp op = SkClipOp::kIntersect)
Replaces Clip with the intersection or difference of Clip and Region deviceRgn. Resulting Clip is Aliased; pixels are fully contained by the clip. deviceRgn is unaffected by Matrix. ### Parameters
deviceRgn Region to combine with Clip
op Clip Op to apply to Clip
### Example
region is unaffected by canvas rotation; iRect is affected by canvas rotation. Both clips are Aliased; this is not noticeable on Region clip because it aligns to pixel boundaries.
### See Also clipRect[2][3] clipRRect[2][3] clipPath[2][3] --- ## quickReject 
bool quickReject(const SkRect& rect) const
Returns true if Rect rect, transformed by Matrix, can be quickly determined to be outside of Clip. May return false even though rect is outside of Clip. Use to check if an area to be drawn is clipped out, to skip subsequent draw calls. ### Parameters
rect Rect to compare with Clip
### Return Value true if rect, transformed by Matrix, does not intersect Clip ### Example
#### Example Output ~~~~ quickReject true quickReject false ~~~~
### See Also getLocalClipBounds[2] getTotalMatrix SkBitmap::drawsNothing --- 
bool quickReject(const SkPath& path) const
Returns true if path, transformed by Matrix, can be quickly determined to be outside of Clip. May return false even though path is outside of Clip. Use to check if an area to be drawn is clipped out, to skip subsequent draw calls. ### Parameters
path Path to compare with Clip
### Return Value true if path, transformed by Matrix, does not intersect Clip ### Example
#### Example Output ~~~~ quickReject true quickReject false ~~~~
### See Also getLocalClipBounds[2] getTotalMatrix SkBitmap::drawsNothing --- ## getLocalClipBounds 
SkRect getLocalClipBounds() const
Returns bounds of Clip, transformed by inverse of Matrix. If Clip is empty, return SkRect::MakeEmpty, where all Rect sides equal zero. Rect returned is outset by one to account for partial pixel coverage if Clip is Anti Aliased. ### Return Value bounds of Clip in local coordinates ### Example
Initial bounds is device bounds outset by 1 on all sides. Clipped bounds is clipPath bounds outset by 1 on all sides. Scaling the canvas by two on both axes scales the local bounds by 1/2 on both axes.
#### Example Output ~~~~ left:-1 top:-1 right:257 bottom:257 left:29 top:129 right:121 bottom:231 left:14.5 top:64.5 right:60.5 bottom:115.5 ~~~~
### See Also getDeviceClipBounds[2] getBaseLayerSize quickReject[2] --- 
bool getLocalClipBounds(SkRect* bounds) const
Returns bounds of Clip, transformed by inverse of Matrix. If Clip is empty, return false, and set bounds to SkRect::MakeEmpty, where all Rect sides equal zero. bounds is outset by one to account for partial pixel coverage if Clip is Anti Aliased. ### Parameters
bounds Rect of Clip in local coordinates
### Return Value true if Clip bounds is not empty ### Example
#### Example Output ~~~~ local bounds empty = false local bounds empty = true ~~~~
### See Also getDeviceClipBounds[2] getBaseLayerSize quickReject[2] --- ## getDeviceClipBounds 
SkIRect getDeviceClipBounds() const
Returns IRect bounds of Clip, unaffected by Matrix. If Clip is empty, return SkRect::MakeEmpty, where all Rect sides equal zero. Unlike getLocalClipBounds, returned IRect is not outset. ### Return Value bounds of Clip in Device coordinates ### Example
Initial bounds is device bounds, not outset. Clipped bounds is clipPath bounds, not outset. Scaling the canvas by 1/2 on both axes scales the device bounds by 1/2 on both axes.
#### Example Output ~~~~ left:0 top:0 right:256 bottom:256 left:30 top:130 right:120 bottom:230 left:15 top:65 right:60 bottom:115 ~~~~
### See Also getLocalClipBounds[2] getBaseLayerSize quickReject[2] --- 
bool getDeviceClipBounds(SkIRect* bounds) const
Returns IRect bounds of Clip, unaffected by Matrix. If Clip is empty, return false, and set bounds to SkRect::MakeEmpty, where all Rect sides equal zero. Unlike getLocalClipBounds, bounds is not outset. ### Parameters
bounds Rect of Clip in device coordinates
### Return Value true if Clip bounds is not empty ### Example
#### Example Output ~~~~ device bounds empty = false device bounds empty = true ~~~~
### See Also getLocalClipBounds[2] getBaseLayerSize quickReject[2] --- ## Draw
Topic Description
clear fills Clip with Color
drawAnnotation associates a Rect with a key-value pair
drawAnnotation(const SkRect& rect, const char key[], SkData* value)
drawAnnotation(const SkRect& rect, const char key[], const sk sp<SkData>& value)
drawArc draws Arc using Clip, Matrix, and Paint
drawAtlas draws sprites using Clip, Matrix, and Paint
drawAtlas(const SkImage* atlas, const SkRSXform xform[], const SkRect tex[], const SkColor colors[], int count, SkBlendMode mode, const SkRect* cullRect, const SkPaint* paint)
drawAtlas(const sk sp<SkImage>& atlas, const SkRSXform xform[], const SkRect tex[], const SkColor colors[], int count, SkBlendMode mode, const SkRect* cullRect, const SkPaint* paint)
drawAtlas(const SkImage* atlas, const SkRSXform xform[], const SkRect tex[], int count, const SkRect* cullRect, const SkPaint* paint)
drawAtlas(const sk sp<SkImage>& atlas, const SkRSXform xform[], const SkRect tex[], int count, const SkRect* cullRect, const SkPaint* paint)
drawCircle draws Circle using Clip, Matrix, and Paint
drawCircle(SkScalar cx, SkScalar cy, SkScalar radius, const SkPaint& paint)
drawCircle(SkPoint center, SkScalar radius, const SkPaint& paint)
drawColor fills Clip with Color and Blend Mode
drawDRRect draws double Round Rect stroked or filled
drawDrawable draws Drawable, encapsulated drawing commands
drawDrawable(SkDrawable* drawable, const SkMatrix* matrix = nullptr)
drawDrawable(SkDrawable* drawable, SkScalar x, SkScalar y)
drawIRect draws IRect using Clip, Matrix, and Paint
drawLine draws line segment between two points
drawLine(SkScalar x0, SkScalar y0, SkScalar x1, SkScalar y1, const SkPaint& paint)
drawLine(SkPoint p0, SkPoint p1, const SkPaint& paint)
drawOval draws Oval using Clip, Matrix, and Paint
drawPaint fills Clip with Paint
drawPatch draws Coons Patch
drawPatch(const SkPoint cubics[12], const SkColor colors[4], const SkPoint texCoords[4], SkBlendMode mode, const SkPaint& paint)
drawPatch(const SkPoint cubics[12], const SkColor colors[4], const SkPoint texCoords[4], const SkPaint& paint)
drawPath draws Path using Clip, Matrix, and Paint
drawPicture draws Picture using Clip and Matrix
drawPicture(const SkPicture* picture)
drawPicture(const sk sp<SkPicture>& picture)
drawPicture(const SkPicture* picture, const SkMatrix* matrix, const SkPaint* paint)
drawPicture(const sk sp<SkPicture>& picture, const SkMatrix* matrix, const SkPaint* paint)
drawPoint draws point at (x, y) position
drawPoint(SkScalar x, SkScalar y, const SkPaint& paint)
drawPoint(SkPoint p, const SkPaint& paint)
drawPoints draws array as points, lines, polygon
drawRRect draws Round Rect using Clip, Matrix, and Paint
drawRect draws Rect using Clip, Matrix, and Paint
drawRegion draws Region using Clip, Matrix, and Paint
drawRoundRect draws Round Rect using Clip, Matrix, and Paint
drawVertices draws Vertices, a triangle mesh
drawVertices(const SkVertices* vertices, SkBlendMode mode, const SkPaint& paint)
drawVertices(const sk sp<SkVertices>& vertices, SkBlendMode mode, const SkPaint& paint)
drawVertices(const SkVertices* vertices, const SkMatrix* bones, int boneCount, SkBlendMode mode, const SkPaint& paint)
drawVertices(const sk sp<SkVertices>& vertices, const SkMatrix* bones, int boneCount, SkBlendMode mode, const SkPaint& paint)
## drawColor 
void drawColor(SkColor color, SkBlendMode mode = SkBlendMode::kSrcOver)
Fills Clip with Color color. mode determines how ARGB is combined with destination. ### Parameters
color Unpremultiplied ARGB
mode SkBlendMode used to combine source color and destination
### Example
### See Also clear SkBitmap::erase drawPaint --- ## clear 
void clear(SkColor color)
Fills Clip with Color color using SkBlendMode::kSrc. This has the effect of replacing all pixels contained by Clip with color. ### Parameters
color Unpremultiplied ARGB
### Example
### See Also drawColor SkBitmap::erase drawPaint --- ## discard 
void discard()
Makes Canvas contents undefined. Subsequent calls that read Canvas pixels, such as drawing with SkBlendMode, return undefined results. discard does not change Clip or Matrix. discard may do nothing, depending on the implementation of Surface or Device that created Canvas. discard allows optimized performance on subsequent draws by removing cached data associated with Surface or Device. It is not necessary to call discard once done with Canvas; any cached data is deleted when owning Surface or Device is deleted. ### See Also flush SkSurface::prepareForExternalIO GrContext::abandonContext --- ## drawPaint 
void drawPaint(const SkPaint& paint)
Fills Clip with Paint paint. Paint components Mask Filter, Shader, Color Filter, Image Filter, and Blend Mode affect drawing; Path Effect in paint is ignored. ### Parameters
paint graphics state used to fill Canvas
### Example
### See Also clear drawColor SkBitmap::erase --- ## Enum SkCanvas::PointMode 
    enum PointMode {
        kPoints PointMode,
        kLines PointMode,
        kPolygon PointMode,
    };
Selects if an array of points are drawn as discrete points, as lines, or as an open polygon. ### Constants
Const Value Description
SkCanvas::kPoints_PointMode 0 draw each point separately
SkCanvas::kLines_PointMode 1 draw each pair of points as a line segment
SkCanvas::kPolygon_PointMode 2 draw the array of points as a open polygon
### Example
The upper left corner shows three squares when drawn as points. The upper right corner shows one line; when drawn as lines, two points are required per line. The lower right corner shows two lines; when draw as polygon, no miter is drawn at the corner. The lower left corner shows two lines with a miter when path contains polygon.
### See Also drawLine[2] drawPoint[2] drawPath ## drawPoints 
void drawPoints(PointMode mode, size_t count, const SkPoint pts[], const SkPaint& paint)
Draws pts using Clip, Matrix and Paint paint. count is the number of points; if count is less than one, has no effect. mode may be one of: kPoints PointMode, kLines PointMode, or kPolygon PointMode. If mode is kPoints PointMode, the shape of point drawn depends on paint Paint Stroke Cap. If paint is set to SkPaint::kRound Cap, each point draws a circle of diameter Paint Stroke Width. If paint is set to SkPaint::kSquare Cap or SkPaint::kButt Cap, each point draws a square of width and height Paint Stroke Width. If mode is kLines PointMode, each pair of points draws a line segment. One line is drawn for every two points; each point is used once. If count is odd, the final point is ignored. If mode is kPolygon PointMode, each adjacent pair of points draws a line segment. count minus one lines are drawn; the first and last point are used once. Each line segment respects paint Paint Stroke Cap and Paint Stroke Width. Paint Style is ignored, as if were set to SkPaint::kStroke Style. Always draws each element one at a time; is not affected by Paint Stroke Join, and unlike drawPath, does not create a mask from all points and lines before drawing. ### Parameters
mode whether pts draws points or lines
count number of points in the array
pts array of points to draw
paint stroke, blend, color, and so on, used to draw
### Example
The first column draws points.
The second column draws points as lines.
The third column draws points as a polygon.
The fourth column draws points as a polygonal path.
The first row uses a round cap and round join.
The second row uses a square cap and a miter join.
The third row uses a butt cap and a bevel join.
The transparent color makes multiple line draws visible; the path is drawn all at once.
### See Also drawLine[2] drawPoint[2] drawPath --- ## drawPoint 
void drawPoint(SkScalar x, SkScalar y, const SkPaint& paint)
Draws point at (x, y) using Clip, Matrix and Paint paint. The shape of point drawn depends on paint Paint Stroke Cap. If paint is set to SkPaint::kRound Cap, draw a circle of diameter Paint Stroke Width. If paint is set to SkPaint::kSquare Cap or SkPaint::kButt Cap, draw a square of width and height Paint Stroke Width. Paint Style is ignored, as if were set to SkPaint::kStroke Style. ### Parameters
x left edge of circle or square
y top edge of circle or square
paint stroke, blend, color, and so on, used to draw
### Example
### See Also drawPoints drawCircle[2] drawRect drawLine[2] drawPath --- 
void drawPoint(SkPoint p, const SkPaint& paint)
Draws point p using Clip, Matrix and Paint paint. The shape of point drawn depends on paint Paint Stroke Cap. If paint is set to SkPaint::kRound Cap, draw a circle of diameter Paint Stroke Width. If paint is set to SkPaint::kSquare Cap or SkPaint::kButt Cap, draw a square of width and height Paint Stroke Width. Paint Style is ignored, as if were set to SkPaint::kStroke Style. ### Parameters
p top-left edge of circle or square
paint stroke, blend, color, and so on, used to draw
### Example
### See Also drawPoints drawCircle[2] drawRect drawLine[2] drawPath --- ## drawLine 
void drawLine(SkScalar x0, SkScalar y0, SkScalar x1, SkScalar y1, const SkPaint& paint)
Draws line segment from (x0, y0) to (x1, y1) using Clip, Matrix, and Paint paint. In paint: Paint Stroke Width describes the line thickness; Paint Stroke Cap draws the end rounded or square; Paint Style is ignored, as if were set to SkPaint::kStroke Style. ### Parameters
x0 start of line segment on x-axis
y0 start of line segment on y-axis
x1 end of line segment on x-axis
y1 end of line segment on y-axis
paint stroke, blend, color, and so on, used to draw
### Example
### See Also drawPoint[2] drawCircle[2] drawRect drawPath --- 
void drawLine(SkPoint p0, SkPoint p1, const SkPaint& paint)
Draws line segment from p0 to p1 using Clip, Matrix, and Paint paint. In paint: Paint Stroke Width describes the line thickness; Paint Stroke Cap draws the end rounded or square; Paint Style is ignored, as if were set to SkPaint::kStroke Style. ### Parameters
p0 start of line segment
p1 end of line segment
paint stroke, blend, color, and so on, used to draw
### Example
### See Also drawPoint[2] drawCircle[2] drawRect drawPath --- ## drawRect 
void drawRect(const SkRect& rect, const SkPaint& paint)
Draws Rect rect using Clip, Matrix, and Paint paint. In paint: Paint Style determines if rectangle is stroked or filled; if stroked, Paint Stroke Width describes the line thickness, and Paint Stroke Join draws the corners rounded or square. ### Parameters
rect rectangle to draw
paint stroke or fill, blend, color, and so on, used to draw
### Example
### See Also drawIRect drawRRect drawRoundRect drawRegion drawPath drawLine[2] --- ## drawIRect 
void drawIRect(const SkIRect& rect, const SkPaint& paint)
Draws IRect rect using Clip, Matrix, and Paint paint. In paint: Paint Style determines if rectangle is stroked or filled; if stroked, Paint Stroke Width describes the line thickness, and Paint Stroke Join draws the corners rounded or square. ### Parameters
rect rectangle to draw
paint stroke or fill, blend, color, and so on, used to draw
### Example
### See Also drawRect drawRRect drawRoundRect drawRegion drawPath drawLine[2] --- ## drawRegion 
void drawRegion(const SkRegion& region, const SkPaint& paint)
Draws Region region using Clip, Matrix, and Paint paint. In paint: Paint Style determines if rectangle is stroked or filled; if stroked, Paint Stroke Width describes the line thickness, and Paint Stroke Join draws the corners rounded or square. ### Parameters
region region to draw
paint Paint stroke or fill, blend, color, and so on, used to draw
### Example
### See Also drawRect drawIRect drawPath --- ## drawOval 
void drawOval(const SkRect& oval, const SkPaint& paint)
Draws Oval oval using Clip, Matrix, and Paint. In paint: Paint Style determines if Oval is stroked or filled; if stroked, Paint Stroke Width describes the line thickness. ### Parameters
oval Rect bounds of Oval
paint Paint stroke or fill, blend, color, and so on, used to draw
### Example
### See Also drawCircle[2] drawPoint[2] drawPath drawRRect drawRoundRect --- ## drawRRect 
void drawRRect(const SkRRect& rrect, const SkPaint& paint)
Draws Round Rect rrect using Clip, Matrix, and Paint paint. In paint: Paint Style determines if rrect is stroked or filled; if stroked, Paint Stroke Width describes the line thickness. rrect may represent a rectangle, circle, oval, uniformly rounded rectangle, or may have any combination of positive non-square radii for the four corners. ### Parameters
rrect Round Rect with up to eight corner radii to draw
paint Paint stroke or fill, blend, color, and so on, used to draw
### Example
### See Also drawRect drawRoundRect drawDRRect drawCircle[2] drawOval drawPath --- ## drawDRRect 
void drawDRRect(const SkRRect& outer, const SkRRect& inner, const SkPaint& paint)
Draws Round Rect outer and inner using Clip, Matrix, and Paint paint. outer must contain inner or the drawing is undefined. In paint: Paint Style determines if Round Rect is stroked or filled; if stroked, Paint Stroke Width describes the line thickness. If stroked and Round Rect corner has zero length radii, Paint Stroke Join can draw corners rounded or square. GPU-backed platforms optimize drawing when both outer and inner are concave and outer contains inner. These platforms may not be able to draw Path built with identical data as fast. ### Parameters
outer Round Rect outer bounds to draw
inner Round Rect inner bounds to draw
paint Paint stroke or fill, blend, color, and so on, used to draw
### Example
### Example
Outer Rect has no corner radii, but stroke join is rounded. Inner Round Rect has corner radii; outset stroke increases radii of corners. Stroke join does not affect inner Round Rect since it has no sharp corners.
### See Also drawRect drawRoundRect drawRRect drawCircle[2] drawOval drawPath --- ## drawCircle 
void drawCircle(SkScalar cx, SkScalar cy, SkScalar radius, const SkPaint& paint)
Draws Circle at (cx, cy) with radius using Clip, Matrix, and Paint paint. If radius is zero or less, nothing is drawn. In paint: Paint Style determines if Circle is stroked or filled; if stroked, Paint Stroke Width describes the line thickness. ### Parameters
cx Circle center on the x-axis
cy Circle center on the y-axis
radius half the diameter of Circle
paint Paint stroke or fill, blend, color, and so on, used to draw
### Example
### See Also drawOval drawRRect drawRoundRect drawPath drawArc drawPoint[2] drawLine[2] --- 
void drawCircle(SkPoint center, SkScalar radius, const SkPaint& paint)
Draws Circle at center with radius using Clip, Matrix, and Paint paint. If radius is zero or less, nothing is drawn. In paint: Paint Style determines if Circle is stroked or filled; if stroked, Paint Stroke Width describes the line thickness. ### Parameters
center Circle center
radius half the diameter of Circle
paint Paint stroke or fill, blend, color, and so on, used to draw
### Example
### See Also drawOval drawRRect drawRoundRect drawPath drawArc drawPoint[2] drawLine[2] --- ## drawArc 
void drawArc(const SkRect& oval, SkScalar startAngle, SkScalar sweepAngle, bool useCenter,
             const SkPaint& paint)
Draws Arc using Clip, Matrix, and Paint paint. Arc is part of Oval bounded by oval, sweeping from startAngle to startAngle plus sweepAngle. startAngle and sweepAngle are in degrees. startAngle of zero places start point at the right middle edge of oval. A positive sweepAngle places Arc end point clockwise from start point; a negative sweepAngle places Arc end point counterclockwise from start point. sweepAngle may exceed 360 degrees, a full circle. If useCenter is true, draw a wedge that includes lines from oval center to Arc end points. If useCenter is false, draw Arc between end points. If Rect oval is empty or sweepAngle is zero, nothing is drawn. ### Parameters
oval Rect bounds of Oval containing Arc to draw
startAngle angle in degrees where Arc begins
sweepAngle sweep angle in degrees; positive is clockwise
useCenter if true, include the center of the oval
paint Paint stroke or fill, blend, color, and so on, used to draw
### Example
### Example
### See Also SkPath::arcTo[2][3][4][5] drawCircle[2] drawOval drawPath --- ## drawRoundRect 
void drawRoundRect(const SkRect& rect, SkScalar rx, SkScalar ry, const SkPaint& paint)
Draws Round Rect bounded by Rect rect, with corner radii (rx, ry) using Clip, Matrix, and Paint paint. In paint: Paint Style determines if Round Rect is stroked or filled; if stroked, Paint Stroke Width describes the line thickness. If rx or ry are less than zero, they are treated as if they are zero. If rx plus ry exceeds rect width or rect height, radii are scaled down to fit. If rx and ry are zero, Round Rect is drawn as Rect and if stroked is affected by Paint Stroke Join. ### Parameters
rect Rect bounds of Round Rect to draw
rx axis length on x-axis of oval describing rounded corners
ry axis length on y-axis of oval describing rounded corners
paint stroke, blend, color, and so on, used to draw
### Example
Top row has a zero radius a generates a rectangle. Second row radii sum to less than sides. Third row radii sum equals sides. Fourth row radii sum exceeds sides; radii are scaled to fit.
### See Also DrawRRect drawRect drawDRRect drawPath drawCircle[2] drawOval drawPoint[2] --- ## drawPath 
void drawPath(const SkPath& path, const SkPaint& paint)
Draws Path path using Clip, Matrix, and Paint paint. Path contains an array of Path Contour, each of which may be open or closed. In paint: Paint Style determines if Round Rect is stroked or filled: if filled, Path Fill Type determines whether Path Contour describes inside or outside of fill; if stroked, Paint Stroke Width describes the line thickness, Paint Stroke Cap describes line ends, and Paint Stroke Join describes how corners are drawn. ### Parameters
path Path to draw
paint stroke, blend, color, and so on, used to draw
### Example
Top rows draw stroked path with combinations of joins and caps. The open contour is affected by caps; the closed contour is affected by joins. Bottom row draws fill the same for open and closed contour. First bottom column shows winding fills overlap. Second bottom column shows even odd fills exclude overlap. Third bottom column shows inverse winding fills area outside both contours.
### See Also SkPath drawLine[2] drawArc drawRect drawPoints --- ## Draw Image drawImage, drawImageRect, and drawImageNine can be called with a bare pointer or a smart pointer as a convenience. The pairs of calls are otherwise identical. ## drawImage 
void drawImage(const SkImage* image, SkScalar left, SkScalar top, const SkPaint* paint = nullptr)
Draws Image image, with its top-left corner at (left, top), using Clip, Matrix, and optional Paint paint. If paint is supplied, apply Color Filter, Color Alpha, Image Filter, Blend Mode, and Draw Looper. If image is kAlpha_8_SkColorType, apply Shader. If paint contains Mask Filter, generate mask from image bounds. If generated mask extends beyond image bounds, replicate image edge colors, just as Shader made from SkImage::makeShader with SkShader::kClamp TileMode set replicates the image edge color when it samples outside of its bounds. ### Parameters
image uncompressed rectangular map of pixels
left left side of image
top top side of image
paint Paint containing Blend Mode, Color Filter, Image Filter, and so on; or nullptr
### Example
### See Also drawBitmap drawImageLattice drawImageNine[2] drawImageRect[2][3][4][5][6] SkPaint::setImageFilter --- 
void drawImage(const sk sp<SkImage>& image, SkScalar left, SkScalar top,
               const SkPaint* paint = nullptr)
Draws Image image, with its top-left corner at (left, top), using Clip, Matrix, and optional Paint paint. If Paint paint is supplied, apply Color Filter, Color Alpha, Image Filter, Blend Mode, and Draw Looper. If image is kAlpha_8_SkColorType, apply Shader. If paint contains Mask Filter, generate mask from image bounds. If generated mask extends beyond image bounds, replicate image edge colors, just as Shader made from SkImage::makeShader with SkShader::kClamp TileMode set replicates the image edge color when it samples outside of its bounds. ### Parameters
image uncompressed rectangular map of pixels
left left side of image
top pop side of image
paint Paint containing Blend Mode, Color Filter, Image Filter, and so on; or nullptr
### Example
### See Also drawBitmap drawImageLattice drawImageNine[2] drawImageRect[2][3][4][5][6] SkPaint::setImageFilter --- ## Enum SkCanvas::SrcRectConstraint 
    enum SrcRectConstraint {
        kStrict SrcRectConstraint,
        kFast SrcRectConstraint,
    };
SrcRectConstraint controls the behavior at the edge of source Rect, provided to drawImageRect, trading off speed for precision. Image Filter in Paint may sample multiple pixels in the image. Source Rect restricts the bounds of pixels that may be read. Image Filter may slow down if it cannot read outside the bounds, when sampling near the edge of source Rect. SrcRectConstraint specifies whether an Image Filter is allowed to read pixels outside source Rect. ### Constants
Const Value Description
SkCanvas::kStrict_SrcRectConstraint 0 Requires Image Filter to respect source Rect, sampling only inside of its bounds, possibly with a performance penalty.
SkCanvas::kFast_SrcRectConstraint 1 Permits Image Filter to sample outside of source Rect by half the width of Image Filter, permitting it to run faster but with error at the image edges.
### Example
redBorder contains a black and white checkerboard bordered by red. redBorder is drawn scaled by 16 on the left. The middle and right bitmaps are filtered checkerboards. Drawing the checkerboard with kStrict SrcRectConstraint shows only a blur of black and white. Drawing the checkerboard with kFast SrcRectConstraint allows red to bleed in the corners.
### See Also drawImageRect[2][3][4][5][6] drawImage[2] SkPaint::setImageFilter ## drawImageRect 
void drawImageRect(const SkImage* image, const SkRect& src, const SkRect& dst, const SkPaint* paint,
                   SrcRectConstraint constraint = kStrict SrcRectConstraint)
Draws Rect src of Image image, scaled and translated to fill Rect dst. Additionally transform draw using Clip, Matrix, and optional Paint paint. If Paint paint is supplied, apply Color Filter, Color Alpha, Image Filter, Blend Mode, and Draw Looper. If image is kAlpha_8_SkColorType, apply Shader. If paint contains Mask Filter, generate mask from image bounds. If generated mask extends beyond image bounds, replicate image edge colors, just as Shader made from SkImage::makeShader with SkShader::kClamp TileMode set replicates the image edge color when it samples outside of its bounds. constraint set to kStrict SrcRectConstraint limits Paint Filter Quality to sample within src; set to kFast SrcRectConstraint allows sampling outside to improve performance. ### Parameters
image Image containing pixels, dimensions, and format
src source Rect of image to draw from
dst destination Rect of image to draw to
paint Paint containing Blend Mode, Color Filter, Image Filter, and so on; or nullptr
constraint filter strictly within src or draw faster
### Example
The left bitmap draws with Paint default kNone_SkFilterQuality, and stays within its bounds; there is no bleeding with kFast SrcRectConstraint. the middle and right bitmaps draw with kLow_SkFilterQuality; with kStrict SrcRectConstraint, the filter remains within the checkerboard, and with kFast SrcRectConstraint red bleeds on the edges.
### See Also SrcRectConstraint drawImage[2] drawImageLattice drawImageNine[2] --- 
void drawImageRect(const SkImage* image, const SkIRect& isrc, const SkRect& dst, const SkPaint* paint,
                   SrcRectConstraint constraint = kStrict SrcRectConstraint)
Draws IRect isrc of Image image, scaled and translated to fill Rect dst. Note that isrc is on integer pixel boundaries; dst may include fractional boundaries. Additionally transform draw using Clip, Matrix, and optional Paint paint. If Paint paint is supplied, apply Color Filter, Color Alpha, Image Filter, Blend Mode, and Draw Looper. If image is kAlpha_8_SkColorType, apply Shader. If paint contains Mask Filter, generate mask from image bounds. If generated mask extends beyond image bounds, replicate image edge colors, just as Shader made from SkImage::makeShader with SkShader::kClamp TileMode set replicates the image edge color when it samples outside of its bounds. constraint set to kStrict SrcRectConstraint limits Paint Filter Quality to sample within isrc; set to kFast SrcRectConstraint allows sampling outside to improve performance. ### Parameters
image Image containing pixels, dimensions, and format
isrc source IRect of image to draw from
dst destination Rect of image to draw to
paint Paint containing Blend Mode, Color Filter, Image Filter, and so on; or nullptr
constraint filter strictly within isrc or draw faster
### Example
### See Also SrcRectConstraint drawImage[2] drawImageLattice drawImageNine[2] --- 
void drawImageRect(const SkImage* image, const SkRect& dst, const SkPaint* paint,
                   SrcRectConstraint constraint = kStrict SrcRectConstraint)
Draws Image image, scaled and translated to fill Rect dst, using Clip, Matrix, and optional Paint paint. If Paint paint is supplied, apply Color Filter, Color Alpha, Image Filter, Blend Mode, and Draw Looper. If image is kAlpha_8_SkColorType, apply Shader. If paint contains Mask Filter, generate mask from image bounds. If generated mask extends beyond image bounds, replicate image edge colors, just as Shader made from SkImage::makeShader with SkShader::kClamp TileMode set replicates the image edge color when it samples outside of its bounds. constraint set to kStrict SrcRectConstraint limits Paint Filter Quality to sample within image; set to kFast SrcRectConstraint allows sampling outside to improve performance. ### Parameters
image Image containing pixels, dimensions, and format
dst destination Rect of image to draw to
paint Paint containing Blend Mode, Color Filter, Image Filter, and so on; or nullptr
constraint filter strictly within image or draw faster
### Example
### See Also SrcRectConstraint drawImage[2] drawImageLattice drawImageNine[2] --- 
void drawImageRect(const sk sp<SkImage>& image, const SkRect& src, const SkRect& dst,
                   const SkPaint* paint, SrcRectConstraint constraint = kStrict SrcRectConstraint)
Draws Rect src of Image image, scaled and translated to fill Rect dst. Additionally transform draw using Clip, Matrix, and optional Paint paint. If Paint paint is supplied, apply Color Filter, Color Alpha, Image Filter, Blend Mode, and Draw Looper. If image is kAlpha_8_SkColorType, apply Shader. If paint contains Mask Filter, generate mask from image bounds. If generated mask extends beyond image bounds, replicate image edge colors, just as Shader made from SkImage::makeShader with SkShader::kClamp TileMode set replicates the image edge color when it samples outside of its bounds. constraint set to kStrict SrcRectConstraint limits Paint Filter Quality to sample within src; set to kFast SrcRectConstraint allows sampling outside to improve performance. ### Parameters
image Image containing pixels, dimensions, and format
src source Rect of image to draw from
dst destination Rect of image to draw to
paint Paint containing Blend Mode, Color Filter, Image Filter, and so on; or nullptr
constraint filter strictly within src or draw faster
### Example
Canvas scales and translates; transformation from src to dst also scales. The two matrices are concatenated to create the final transformation.
### See Also SrcRectConstraint drawImage[2] drawImageLattice drawImageNine[2] --- 
void drawImageRect(const sk sp<SkImage>& image, const SkIRect& isrc, const SkRect& dst,
                   const SkPaint* paint, SrcRectConstraint constraint = kStrict SrcRectConstraint)
Draws IRect isrc of Image image, scaled and translated to fill Rect dst. isrc is on integer pixel boundaries; dst may include fractional boundaries. Additionally transform draw using Clip, Matrix, and optional Paint paint. If Paint paint is supplied, apply Color Filter, Color Alpha, Image Filter, Blend Mode, and Draw Looper. If image is kAlpha_8_SkColorType, apply Shader. If paint contains Mask Filter, generate mask from image bounds. If generated mask extends beyond image bounds, replicate image edge colors, just as Shader made from SkImage::makeShader with SkShader::kClamp TileMode set replicates the image edge color when it samples outside of its bounds. constraint set to kStrict SrcRectConstraint limits Paint Filter Quality to sample within image; set to kFast SrcRectConstraint allows sampling outside to improve performance. ### Parameters
image Image containing pixels, dimensions, and format
isrc source IRect of image to draw from
dst destination Rect of image to draw to
paint Paint containing Blend Mode, Color Filter, Image Filter, and so on; or nullptr
constraint filter strictly within image or draw faster
### Example
### See Also SrcRectConstraint drawImage[2] drawImageLattice drawImageNine[2] --- 
void drawImageRect(const sk sp<SkImage>& image, const SkRect& dst, const SkPaint* paint,
                   SrcRectConstraint constraint = kStrict SrcRectConstraint)
Draws Image image, scaled and translated to fill Rect dst, using Clip, Matrix, and optional Paint paint. If Paint paint is supplied, apply Color Filter, Color Alpha, Image Filter, Blend Mode, and Draw Looper. If image is kAlpha_8_SkColorType, apply Shader. If paint contains Mask Filter, generate mask from image bounds. If generated mask extends beyond image bounds, replicate image edge colors, just as Shader made from SkImage::makeShader with SkShader::kClamp TileMode set replicates the image edge color when it samples outside of its bounds. constraint set to kStrict SrcRectConstraint limits Paint Filter Quality to sample within image; set to kFast SrcRectConstraint allows sampling outside to improve performance. ### Parameters
image Image containing pixels, dimensions, and format
dst destination Rect of image to draw to
paint Paint containing Blend Mode, Color Filter, Image Filter, and so on; or nullptr
constraint filter strictly within image or draw faster
### Example
### See Also SrcRectConstraint drawImage[2] drawImageLattice drawImageNine[2] --- ## drawImageNine 
void drawImageNine(const SkImage* image, const SkIRect& center, const SkRect& dst,
                   const SkPaint* paint = nullptr)
Draws Image image stretched proportionally to fit into Rect dst. IRect center divides the image into nine sections: four sides, four corners, and the center. Corners are unmodified or scaled down proportionately if their sides are larger than dst; center and four sides are scaled to fit remaining space, if any. Additionally transform draw using Clip, Matrix, and optional Paint paint. If Paint paint is supplied, apply Color Filter, Color Alpha, Image Filter, Blend Mode, and Draw Looper. If image is kAlpha_8_SkColorType, apply Shader. If paint contains Mask Filter, generate mask from image bounds. If paint Filter Quality set to kNone_SkFilterQuality, disable pixel filtering. For all other values of paint Filter Quality, use kLow_SkFilterQuality to filter pixels. Any SkMaskFilter on paint is ignored as is paint Anti Aliasing state. If generated mask extends beyond image bounds, replicate image edge colors, just as Shader made from SkImage::makeShader with SkShader::kClamp TileMode set replicates the image edge color when it samples outside of its bounds. ### Parameters
image Image containing pixels, dimensions, and format
center IRect edge of image corners and sides
dst destination Rect of image to draw to
paint Paint containing Blend Mode, Color Filter, Image Filter, and so on; or nullptr
### Example
The leftmost image is smaller than center; only corners are drawn, all scaled to fit. The second image equals the size of center; only corners are drawn without scaling. The remaining images are larger than center. All corners draw without scaling. The sides and center are scaled if needed to take up the remaining space.
### See Also drawImage[2] drawBitmapNine drawImageLattice drawImageRect[2][3][4][5][6] --- 
void drawImageNine(const sk sp<SkImage>& image, const SkIRect& center, const SkRect& dst,
                   const SkPaint* paint = nullptr)
Draws Image image stretched proportionally to fit into Rect dst. IRect center divides the image into nine sections: four sides, four corners, and the center. Corners are not scaled, or scaled down proportionately if their sides are larger than dst; center and four sides are scaled to fit remaining space, if any. Additionally transform draw using Clip, Matrix, and optional Paint paint. If Paint paint is supplied, apply Color Filter, Color Alpha, Image Filter, Blend Mode, and Draw Looper. If image is kAlpha_8_SkColorType, apply Shader. If paint contains Mask Filter, generate mask from image bounds. If paint Filter Quality set to kNone_SkFilterQuality, disable pixel filtering. For all other values of paint Filter Quality, use kLow_SkFilterQuality to filter pixels. Any SkMaskFilter on paint is ignored as is paint Anti Aliasing state. If generated mask extends beyond image bounds, replicate image edge colors, just as Shader made from SkImage::makeShader with SkShader::kClamp TileMode set replicates the image edge color when it samples outside of its bounds. ### Parameters
image Image containing pixels, dimensions, and format
center IRect edge of image corners and sides
dst destination Rect of image to draw to
paint Paint containing Blend Mode, Color Filter, Image Filter, and so on; or nullptr
### Example
The two leftmost images has four corners and sides to the left and right of center. The leftmost image scales the width of corners proportionately to fit. The third and fourth image corners are not scaled; the sides and center are scaled to fill the remaining space. The rightmost image has four corners scaled vertically to fit, and uses sides above and below center to fill the remaining space.
### See Also drawImage[2] drawBitmapNine drawImageLattice drawImageRect[2][3][4][5][6] --- ## drawBitmap 
void drawBitmap(const SkBitmap& bitmap, SkScalar left, SkScalar top, const SkPaint* paint = nullptr)
Draws Bitmap bitmap, with its top-left corner at (left, top), using Clip, Matrix, and optional Paint paint. If Paint paint is not nullptr, apply Color Filter, Color Alpha, Image Filter, Blend Mode, and Draw Looper. If bitmap is kAlpha_8_SkColorType, apply Shader. If paint contains Mask Filter, generate mask from bitmap bounds. If generated mask extends beyond bitmap bounds, replicate bitmap edge colors, just as Shader made from SkShader::MakeBitmapShader with SkShader::kClamp TileMode set replicates the bitmap edge color when it samples outside of its bounds. ### Parameters
bitmap Bitmap containing pixels, dimensions, and format
left left side of bitmap
top top side of bitmap
paint Paint containing Blend Mode, Color Filter, Image Filter, and so on; or nullptr
### Example
### See Also drawImage[2] drawBitmapLattice drawBitmapNine drawBitmapRect[2][3] SkBitmap::readPixels[2][3] SkBitmap::writePixels[2] --- ## drawBitmapRect 
void drawBitmapRect(const SkBitmap& bitmap, const SkRect& src, const SkRect& dst,
                    const SkPaint* paint, SrcRectConstraint constraint = kStrict SrcRectConstraint)
Draws Rect src of Bitmap bitmap, scaled and translated to fill Rect dst. Additionally transform draw using Clip, Matrix, and optional Paint paint. If Paint paint is supplied, apply Color Filter, Color Alpha, Image Filter, Blend Mode, and Draw Looper. If bitmap is kAlpha_8_SkColorType, apply Shader. If paint contains Mask Filter, generate mask from bitmap bounds. If generated mask extends beyond bitmap bounds, replicate bitmap edge colors, just as Shader made from SkShader::MakeBitmapShader with SkShader::kClamp TileMode set replicates the bitmap edge color when it samples outside of its bounds. constraint set to kStrict SrcRectConstraint limits Paint Filter Quality to sample within src; set to kFast SrcRectConstraint allows sampling outside to improve performance. ### Parameters
bitmap Bitmap containing pixels, dimensions, and format
src source Rect of image to draw from
dst destination Rect of image to draw to
paint Paint containing Blend Mode, Color Filter, Image Filter, and so on; or nullptr
constraint filter strictly within src or draw faster
### Example
### See Also drawImageRect[2][3][4][5][6] drawBitmap drawBitmapLattice drawBitmapNine --- 
void drawBitmapRect(const SkBitmap& bitmap, const SkIRect& isrc, const SkRect& dst,
                    const SkPaint* paint, SrcRectConstraint constraint = kStrict SrcRectConstraint)
Draws IRect isrc of Bitmap bitmap, scaled and translated to fill Rect dst. isrc is on integer pixel boundaries; dst may include fractional boundaries. Additionally transform draw using Clip, Matrix, and optional Paint paint. If Paint paint is supplied, apply Color Filter, Color Alpha, Image Filter, Blend Mode, and Draw Looper. If bitmap is kAlpha_8_SkColorType, apply Shader. If paint contains Mask Filter, generate mask from bitmap bounds. If generated mask extends beyond bitmap bounds, replicate bitmap edge colors, just as Shader made from SkShader::MakeBitmapShader with SkShader::kClamp TileMode set replicates the bitmap edge color when it samples outside of its bounds. constraint set to kStrict SrcRectConstraint limits Paint Filter Quality to sample within isrc; set to kFast SrcRectConstraint allows sampling outside to improve performance. ### Parameters
bitmap Bitmap containing pixels, dimensions, and format
isrc source IRect of image to draw from
dst destination Rect of image to draw to
paint Paint containing Blend Mode, Color Filter, Image Filter, and so on; or nullptr
constraint sample strictly within isrc, or draw faster
### Example
### See Also drawImageRect[2][3][4][5][6] drawBitmap drawBitmapLattice drawBitmapNine --- 
void drawBitmapRect(const SkBitmap& bitmap, const SkRect& dst, const SkPaint* paint,
                    SrcRectConstraint constraint = kStrict SrcRectConstraint)
Draws Bitmap bitmap, scaled and translated to fill Rect dst. bitmap bounds is on integer pixel boundaries; dst may include fractional boundaries. Additionally transform draw using Clip, Matrix, and optional Paint paint. If Paint paint is supplied, apply Color Filter, Color Alpha, Image Filter, Blend Mode, and Draw Looper. If bitmap is kAlpha_8_SkColorType, apply Shader. If paint contains Mask Filter, generate mask from bitmap bounds. If generated mask extends beyond bitmap bounds, replicate bitmap edge colors, just as Shader made from SkShader::MakeBitmapShader with SkShader::kClamp TileMode set replicates the bitmap edge color when it samples outside of its bounds. constraint set to kStrict SrcRectConstraint limits Paint Filter Quality to sample within bitmap; set to kFast SrcRectConstraint allows sampling outside to improve performance. ### Parameters
bitmap Bitmap containing pixels, dimensions, and format
dst destination Rect of image to draw to
paint Paint containing Blend Mode, Color Filter, Image Filter, and so on; or nullptr
constraint filter strictly within bitmap or draw faster
### Example
### See Also drawImageRect[2][3][4][5][6] drawBitmap drawBitmapLattice drawBitmapNine --- ## drawBitmapNine 
void drawBitmapNine(const SkBitmap& bitmap, const SkIRect& center, const SkRect& dst,
                    const SkPaint* paint = nullptr)
Draws Bitmap bitmap stretched proportionally to fit into Rect dst. IRect center divides the bitmap into nine sections: four sides, four corners, and the center. Corners are not scaled, or scaled down proportionately if their sides are larger than dst; center and four sides are scaled to fit remaining space, if any. Additionally transform draw using Clip, Matrix, and optional Paint paint. If Paint paint is supplied, apply Color Filter, Color Alpha, Image Filter, Blend Mode, and Draw Looper. If bitmap is kAlpha_8_SkColorType, apply Shader. If paint contains Mask Filter, generate mask from bitmap bounds. If paint Filter Quality set to kNone_SkFilterQuality, disable pixel filtering. For all other values of paint Filter Quality, use kLow_SkFilterQuality to filter pixels. Any SkMaskFilter on paint is ignored as is paint Anti Aliasing state. If generated mask extends beyond bitmap bounds, replicate bitmap edge colors, just as Shader made from SkShader::MakeBitmapShader with SkShader::kClamp TileMode set replicates the bitmap edge color when it samples outside of its bounds. ### Parameters
bitmap Bitmap containing pixels, dimensions, and format
center IRect edge of image corners and sides
dst destination Rect of image to draw to
paint Paint containing Blend Mode, Color Filter, Image Filter, and so on; or nullptr
### Example
The two leftmost bitmap draws has four corners and sides to the left and right of center. The leftmost bitmap draw scales the width of corners proportionately to fit. The third and fourth draw corners are not scaled; the sides and center are scaled to fill the remaining space. The rightmost bitmap draw has four corners scaled vertically to fit, and uses sides above and below center to fill the remaining space.
### See Also drawImageNine[2] drawBitmap drawBitmapLattice drawBitmapRect[2][3] --- ## Draw Image Lattice # Struct SkCanvas::Lattice 
    struct Lattice {
        enum RectType ...

        const int*      fXDivs;
        const int*      fYDivs;
        const RectType* fRectTypes;
        int             fXCount;
        int             fYCount;
        const SkIRect*  fBounds;
        const SkColor*  fColors;
    };
Lattice divides Bitmap or Image into a rectangular grid. Grid entries on even columns and even rows are fixed; these entries are always drawn at their original size if the destination is large enough. If the destination side is too small to hold the fixed entries, all fixed entries are proportionately scaled down to fit. The grid entries not on even columns and rows are scaled to fit the remaining space, if any. ## Draw Image Lattice Overview
Topic Description
Constants enum and enum class, and their const values
Members member values
## Draw Image Lattice Constant
Topic Description
## Enum SkCanvas::Lattice::RectType 
            enum RectType : uint8_t {
                kDefault = 0,
                kTransparent,
                kFixedColor,
            };
Optional setting per rectangular grid entry to make it transparent, or to fill the grid entry with a color. ### Constants
Const Value Description
SkCanvas::Lattice::kDefault 0 draws Bitmap into lattice rectangle
SkCanvas::Lattice::kTransparent 1 skips lattice rectangle by making it transparent
SkCanvas::Lattice::kFixedColor 2 draws one of fColors into lattice rectangle
## Draw Image Lattice Member
Topic Description
### Members
Type Name Description
const int* fXDivs Array of x-axis values that divide the bitmap vertically. Array entries must be unique, increasing, greater than or equal to fBounds left edge, and less than fBounds right edge. Set the first element to fBounds left to collapse the left column of fixed grid entries.
const int* fYDivs Array of y-axis values that divide the bitmap horizontally. Array entries must be unique, increasing, greater than or equal to fBounds top edge, and less than fBounds bottom edge. Set the first element to fBounds top to collapse the top row of fixed grid entries.
const RectType* fRectTypes Optional array of fill types, one per rectangular grid entry: array length must be( fXCount + 1) * (fYCount + 1) . Each RectType is one of: kDefault, kTransparent, kFixedColor. Array entries correspond to the rectangular grid entries, ascending left to right and then top to bottom.
int fXCount Number of entries in fXDivs array; one less than the number of horizontal divisions.
int fYCount Number of entries in fYDivs array; one less than the number of vertical divisions.
const SkIRect* fBounds Optional subset IRect source to draw from. If nullptr, source bounds is dimensions of Bitmap or Image.
const SkColor* fColors Optional array of colors, one per rectangular grid entry. Array length must be( fXCount + 1) * (fYCount + 1) . Array entries correspond to the rectangular grid entries, ascending left to right, then top to bottom.
## drawBitmapLattice 
void drawBitmapLattice(const SkBitmap& bitmap, const Lattice& lattice, const SkRect& dst,
                       const SkPaint* paint = nullptr)
Draws Bitmap bitmap stretched proportionally to fit into Rect dst. Lattice lattice divides bitmap into a rectangular grid. Each intersection of an even-numbered row and column is fixed; like the corners of drawBitmapNine, fixed lattice elements never scale larger than their initial size and shrink proportionately when all fixed elements exceed the bitmap dimension. All other grid elements scale to fill the available space, if any. Additionally transform draw using Clip, Matrix, and optional Paint paint. If Paint paint is supplied, apply Color Filter, Color Alpha, Image Filter, Blend Mode, and Draw Looper. If bitmap is kAlpha_8_SkColorType, apply Shader. If paint contains Mask Filter, generate mask from bitmap bounds. If paint Filter Quality set to kNone_SkFilterQuality, disable pixel filtering. For all other values of paint Filter Quality, use kLow_SkFilterQuality to filter pixels. Any SkMaskFilter on paint is ignored as is paint Anti Aliasing state. If generated mask extends beyond bitmap bounds, replicate bitmap edge colors, just as Shader made from SkShader::MakeBitmapShader with SkShader::kClamp TileMode set replicates the bitmap edge color when it samples outside of its bounds. ### Parameters
bitmap Bitmap containing pixels, dimensions, and format
lattice division of bitmap into fixed and variable rectangles
dst destination Rect of image to draw to
paint Paint containing Blend Mode, Color Filter, Image Filter, and so on; or nullptr
### Example
The two leftmost bitmap draws has four corners and sides to the left and right of center. The leftmost bitmap draw scales the width of corners proportionately to fit. The third and fourth draw corners are not scaled; the sides are scaled to fill the remaining space; the center is transparent. The rightmost bitmap draw has four corners scaled vertically to fit, and uses sides above and below center to fill the remaining space.
### See Also drawImageLattice drawBitmap drawBitmapNine Lattice --- ## drawImageLattice 
void drawImageLattice(const SkImage* image, const Lattice& lattice, const SkRect& dst,
                      const SkPaint* paint = nullptr)
Draws Image image stretched proportionally to fit into Rect dst. Lattice lattice divides image into a rectangular grid. Each intersection of an even-numbered row and column is fixed; like the corners of drawBitmapNine, fixed lattice elements never scale larger than their initial size and shrink proportionately when all fixed elements exceed the bitmap dimension. All other grid elements scale to fill the available space, if any. Additionally transform draw using Clip, Matrix, and optional Paint paint. If Paint paint is supplied, apply Color Filter, Color Alpha, Image Filter, Blend Mode, and Draw Looper. If image is kAlpha_8_SkColorType, apply Shader. If paint contains Mask Filter, generate mask from image bounds. If paint Filter Quality set to kNone_SkFilterQuality, disable pixel filtering. For all other values of paint Filter Quality, use kLow_SkFilterQuality to filter pixels. Any SkMaskFilter on paint is ignored as is paint Anti Aliasing state. If generated mask extends beyond bitmap bounds, replicate bitmap edge colors, just as Shader made from SkShader::MakeBitmapShader with SkShader::kClamp TileMode set replicates the bitmap edge color when it samples outside of its bounds. ### Parameters
image Image containing pixels, dimensions, and format
lattice division of bitmap into fixed and variable rectangles
dst destination Rect of image to draw to
paint Paint containing Blend Mode, Color Filter, Image Filter, and so on; or nullptr
### Example
The leftmost image is smaller than center; only corners are drawn, all scaled to fit. The second image equals the size of center; only corners are drawn without scaling. The remaining images are larger than center. All corners draw without scaling. The sides are scaled if needed to take up the remaining space; the center is transparent.
### See Also drawBitmapLattice drawImage[2] drawImageNine[2] Lattice --- ## Draw Text
Topic Description
drawPosText draws text at array of (x, y) positions
drawPosTextH draws text at x positions with common baseline
drawString draws null terminated string at (x, y) using font advance
drawString(const char* string, SkScalar x, SkScalar y, const SkPaint& paint)
drawString(const SkString& string, SkScalar x, SkScalar y, const SkPaint& paint)
drawText draws text at (x, y), using font advance
drawTextBlob draws text with arrays of positions and Paint
drawTextBlob(const SkTextBlob* blob, SkScalar x, SkScalar y, const SkPaint& paint)
drawTextBlob(const sk sp<SkTextBlob>& blob, SkScalar x, SkScalar y, const SkPaint& paint)
drawTextOnPath draws text following Path contour
drawTextOnPathHV draws text following Path with offsets
drawTextRSXform draws text with array of RSXform
## drawText 
void drawText(const void* text, size_t byteLength, SkScalar x, SkScalar y, const SkPaint& paint)
Draws text, with origin at (x, y), using Clip, Matrix, and Paint paint. text meaning depends on Paint Text Encoding; by default, text is encoded as UTF-8. x and y meaning depends on Paint Text Align and Paint Vertical Text; by default text draws left to right, positioning the first glyph left side bearing at x and its baseline at y. Text size is affected by Matrix and Paint Text Size. All elements of paint: Path Effect, Mask Filter, Shader, Color Filter, Image Filter, and Draw Looper; apply to text. By default, draws filled 12 point black Glyphs. ### Parameters
text character code points or Glyphs drawn
byteLength byte length of text array
x start of text on x-axis
y start of text on y-axis
paint text size, blend, color, and so on, used to draw
### Example
The same text is drawn varying Paint Text Size and varying Matrix.
### See Also drawString[2] drawPosText drawPosTextH drawTextBlob[2] drawTextOnPath drawTextRSXform --- ## drawString 
void drawString(const char* string, SkScalar x, SkScalar y, const SkPaint& paint)
Draws null terminated string, with origin at (x, y), using Clip, Matrix, and Paint paint. string meaning depends on Paint Text Encoding; by default, strings are encoded as UTF-8. Other values of Paint Text Encoding are unlikely to produce the desired results, since zero bytes may be embedded in the string. x and y meaning depends on Paint Text Align and Paint Vertical Text; by default string draws left to right, positioning the first glyph left side bearing at x and its baseline at y. Text size is affected by Matrix and Paint Text Size. All elements of paint: Path Effect, Mask Filter, Shader, Color Filter, Image Filter, and Draw Looper; apply to text. By default, draws filled 12 point black Glyphs. ### Parameters
string character code points or Glyphs drawn, ending with a char value of zero
x start of string on x-axis
y start of string on y-axis
paint text size, blend, color, and so on, used to draw
### Example
### See Also drawText drawPosText drawPosTextH drawTextBlob[2] drawTextOnPath drawTextRSXform --- 
void drawString(const SkString& string, SkScalar x, SkScalar y, const SkPaint& paint)
Draws null terminated string, with origin at (x, y), using Clip, Matrix, and Paint paint. string meaning depends on Paint Text Encoding; by default, strings are encoded as UTF-8. Other values of Paint Text Encoding are unlikely to produce the desired results, since zero bytes may be embedded in the string. x and y meaning depends on Paint Text Align and Paint Vertical Text; by default string draws left to right, positioning the first glyph left side bearing at x and its baseline at y. Text size is affected by Matrix and Paint Text Size. All elements of paint: Path Effect, Mask Filter, Shader, Color Filter, Image Filter, and Draw Looper; apply to text. By default, draws filled 12 point black Glyphs. ### Parameters
string character code points or Glyphs drawn, ending with a char value of zero
x start of string on x-axis
y start of string on y-axis
paint text size, blend, color, and so on, used to draw
### Example
### See Also drawText drawPosText drawPosTextH drawTextBlob[2] drawTextOnPath drawTextRSXform --- ## drawPosText 
void drawPosText(const void* text, size_t byteLength, const SkPoint pos[], const SkPaint& paint)
Draws each glyph in text with the origin in pos array, using Clip, Matrix, and Paint paint. The number of entries in pos array must match the number of Glyphs described by byteLength of text. text meaning depends on Paint Text Encoding; by default, text is encoded as UTF-8. pos elements meaning depends on Paint Vertical Text; by default glyph left side bearing and baseline are relative to Point in pos array. Text size is affected by Matrix and Paint Text Size. All elements of paint: Path Effect, Mask Filter, Shader, Color Filter, Image Filter, and Draw Looper; apply to text. By default, draws filled 12 point black Glyphs. Layout engines such as Harfbuzz typically position each glyph rather than using the font advance widths. ### Parameters
text character code points or Glyphs drawn
byteLength byte length of text array
pos array of glyph origins
paint text size, blend, color, and so on, used to draw
### Example
### See Also drawText drawPosTextH drawTextBlob[2] drawTextOnPath drawTextRSXform --- ## drawPosTextH 
void drawPosTextH(const void* text, size_t byteLength, const SkScalar xpos[], SkScalar constY,
                  const SkPaint& paint)
Draws each glyph in text with its (x, y) origin composed from xpos array and constY, using Clip, Matrix, and Paint paint. The number of entries in xpos array must match the number of Glyphs described by byteLength of text. text meaning depends on Paint Text Encoding; by default, text is encoded as UTF-8. xpos elements meaning depends on Paint Vertical Text; by default each glyph left side bearing is positioned at an xpos element and its baseline is positioned at constY. Text size is affected by Matrix and Paint Text Size. All elements of paint: Path Effect, Mask Filter, Shader, Color Filter, Image Filter, and Draw Looper; apply to text. By default, draws filled 12 point black Glyphs. Layout engines such as Harfbuzz typically position each glyph rather than using the font advance widths if all Glyphs share the same baseline. ### Parameters
text character code points or Glyphs drawn
byteLength byte length of text array
xpos array of x-axis positions, used to position each glyph
constY shared y-axis value for all of x-axis positions
paint text size, blend, color, and so on, used to draw
### Example
### See Also drawText drawPosText drawTextBlob[2] drawTextOnPath drawTextRSXform --- ## drawTextOnPathHV 
void drawTextOnPathHV(const void* text, size_t byteLength, const SkPath& path, SkScalar hOffset,
                      SkScalar vOffset, const SkPaint& paint)
Draws text on Path path, using Clip, Matrix, and Paint paint. Origin of text is at distance hOffset along the path, offset by a perpendicular vector of length vOffset. If the path section corresponding the glyph advance is curved, the glyph is drawn curved to match; control points in the glyph are mapped to projected points parallel to the path. If the text advance is larger than the path length, the excess text is clipped. text meaning depends on Paint Text Encoding; by default, text is encoded as UTF-8. Origin meaning depends on Paint Text Align and Paint Vertical Text; by default text positions the first glyph left side bearing and baseline relative to origin. Text size is affected by Matrix and Paint Text Size. All elements of paint: Path Effect, Mask Filter, Shader, Color Filter, Image Filter, and Draw Looper; apply to text. By default, draws filled 12 point black Glyphs. ### Parameters
text character code points or Glyphs drawn
byteLength byte length of text array
path Path providing text baseline
hOffset distance along path to offset origin
vOffset offset of text above (if negative) or below (if positive) the path
paint text size, blend, color, and so on, used to draw
### Example
### See Also drawTextOnPath drawText drawPosTextH drawTextBlob[2] drawTextRSXform --- ## drawTextOnPath 
void drawTextOnPath(const void* text, size_t byteLength, const SkPath& path, const SkMatrix* matrix,
                    const SkPaint& paint)
Draws text on Path path, using Clip, Matrix, and Paint paint. Origin of text is at beginning of path offset by matrix, if not nullptr. matrix transforms text before text is mapped to path. If the path section corresponding the glyph advance is curved, the glyph is drawn curved to match; control points in the glyph are mapped to projected points parallel to the path. If the text advance is larger than the path length, the excess text is clipped. matrix does not effect paint Shader. text meaning depends on Paint Text Encoding; by default, text is encoded as UTF-8. Origin meaning depends on Paint Text Align and Paint Vertical Text; by default text positions the first glyph left side bearing and baseline relative to origin. Text size is affected by matrix parameter, Canvas Matrix, and Paint Text Size. All elements of paint: Path Effect, Mask Filter, Shader, Color Filter, Image Filter, and Draw Looper; apply to text. By default, draws filled 12 point black Glyphs. ### Parameters
text character code points or Glyphs drawn
byteLength byte length of text array
path Path providing text baseline
matrix transform of Glyphs before mapping to path; may be nullptr to use identity Matrix
paint text size, blend, color, and so on, used to draw
### Example
### See Also drawTextOnPathHV drawText drawPosTextH drawTextBlob[2] drawTextRSXform --- ## drawTextRSXform 
void drawTextRSXform(const void* text, size_t byteLength, const SkRSXform xform[],
                     const SkRect* cullRect, const SkPaint& paint)
Draws text, transforming each glyph by the corresponding SkRSXform, using Clip, Matrix, and Paint paint. RSXform xform array specifies a separate square scale, rotation, and translation for each glyph. xform does not affect paint Shader. Optional Rect cullRect is a conservative bounds of text, taking into account RSXform and paint. If cullRect is outside of Clip, canvas can skip drawing. All elements of paint: Path Effect, Mask Filter, Shader, Color Filter, Image Filter, and Draw Looper; apply to text. By default, draws filled 12 point black Glyphs. ### Parameters
text character code points or Glyphs drawn
byteLength byte length of text array
xform RSXform rotates, scales, and translates each glyph individually
cullRect Rect bounds of text for efficient clipping; or nullptr
paint text size, blend, color, and so on, used to draw
### Example
### See Also drawTextOnPath drawTextOnPathHV drawText drawPosText drawTextBlob[2] --- ## drawTextBlob 
void drawTextBlob(const SkTextBlob* blob, SkScalar x, SkScalar y, const SkPaint& paint)
Draws Text Blob blob at (x, y), using Clip, Matrix, and Paint paint. blob contains Glyphs, their positions, and paint attributes specific to text: Typeface, Paint Text Size, Paint Text Scale X, Paint Text Skew X, Paint Text Align, Paint Hinting, Anti Alias, Paint Fake Bold, Font Embedded Bitmaps, Full Hinting Spacing, LCD Text, Linear Text, Subpixel Text, and Paint Vertical Text. Paint Text Encoding must be set to SkPaint::kGlyphID TextEncoding. Elements of paint: Path Effect, Mask Filter, Shader, Color Filter, Image Filter, and Draw Looper; apply to blob. ### Parameters
blob Glyphs, positions, and their paints' text size, typeface, and so on
x horizontal offset applied to blob
y vertical offset applied to blob
paint blend, color, stroking, and so on, used to draw
### Example
### See Also drawText drawPosText drawPosTextH --- 
void drawTextBlob(const sk sp<SkTextBlob>& blob, SkScalar x, SkScalar y, const SkPaint& paint)
Draws Text Blob blob at (x, y), using Clip, Matrix, and Paint paint. blob contains Glyphs, their positions, and paint attributes specific to text: Typeface, Paint Text Size, Paint Text Scale X, Paint Text Skew X, Paint Text Align, Paint Hinting, Anti Alias, Paint Fake Bold, Font Embedded Bitmaps, Full Hinting Spacing, LCD Text, Linear Text, Subpixel Text, and Paint Vertical Text. Paint Text Encoding must be set to SkPaint::kGlyphID TextEncoding. Elements of paint: Path Effect, Mask Filter, Shader, Color Filter, Image Filter, and Draw Looper; apply to blob. ### Parameters
blob Glyphs, positions, and their paints' text size, typeface, and so on
x horizontal offset applied to blob
y vertical offset applied to blob
paint blend, color, stroking, and so on, used to draw
### Example
Paint attributes unrelated to text, like color, have no effect on paint in allocated Text Blob. Paint attributes related to text, like text size, have no effect on paint passed to drawTextBlob.
### See Also drawText drawPosText drawPosTextH --- ## drawPicture 
void drawPicture(const SkPicture* picture)
Draws Picture picture, using Clip and Matrix. Clip and Matrix are unchanged by picture contents, as if save was called before and restore was called after drawPicture. Picture records a series of draw commands for later playback. ### Parameters
picture recorded drawing commands to play
### Example
### See Also drawDrawable[2] SkPicture SkPicture::playback --- 
void drawPicture(const sk sp<SkPicture>& picture)
Draws Picture picture, using Clip and Matrix. Clip and Matrix are unchanged by picture contents, as if save was called before and restore was called after drawPicture. Picture records a series of draw commands for later playback. ### Parameters
picture recorded drawing commands to play
### Example
### See Also drawDrawable[2] SkPicture SkPicture::playback --- 
void drawPicture(const SkPicture* picture, const SkMatrix* matrix, const SkPaint* paint)
Draws Picture picture, using Clip and Matrix; transforming picture with Matrix matrix, if provided; and use Paint paint Color Alpha, Color Filter, Image Filter, and Blend Mode, if provided. matrix transformation is equivalent to: save, concat, drawPicture, restore. paint use is equivalent to: saveLayer, drawPicture, restore. ### Parameters
picture recorded drawing commands to play
matrix Matrix to rotate, scale, translate, and so on; may be nullptr
paint Paint to apply transparency, filtering, and so on; may be nullptr
### Example
### See Also drawDrawable[2] SkPicture SkPicture::playback --- 
void drawPicture(const sk sp<SkPicture>& picture, const SkMatrix* matrix, const SkPaint* paint)
Draws Picture picture, using Clip and Matrix; transforming picture with Matrix matrix, if provided; and use Paint paint Color Alpha, Color Filter, Image Filter, and Blend Mode, if provided. matrix transformation is equivalent to: save, concat, drawPicture, restore. paint use is equivalent to: saveLayer, drawPicture, restore. ### Parameters
picture recorded drawing commands to play
matrix Matrix to rotate, scale, translate, and so on; may be nullptr
paint Paint to apply transparency, filtering, and so on; may be nullptr
### Example
### See Also drawDrawable[2] SkPicture SkPicture::playback --- ## drawVertices 
void drawVertices(const SkVertices* vertices, SkBlendMode mode, const SkPaint& paint)
Draws Vertices vertices, a triangle mesh, using Clip and Matrix. If Vertices Texs and Vertices Colors are defined in vertices, and Paint paint contains Shader, Blend Mode mode combines Vertices Colors with Shader. ### Parameters
vertices triangle mesh to draw
mode combines Vertices Colors with Shader, if both are present
paint specifies the Shader, used as Vertices texture; may be nullptr
### Example
### See Also drawPatch[2] drawPicture[2][3][4] --- 
void drawVertices(const sk sp<SkVertices>& vertices, SkBlendMode mode, const SkPaint& paint)
Draws Vertices vertices, a triangle mesh, using Clip and Matrix. If Vertices Texs and Vertices Colors are defined in vertices, and Paint paint contains Shader, Blend Mode mode combines Vertices Colors with Shader. ### Parameters
vertices triangle mesh to draw
mode combines Vertices Colors with Shader, if both are present
paint specifies the Shader, used as Vertices texture, may be nullptr
### Example
### See Also drawPatch[2] drawPicture[2][3][4] --- 
void drawVertices(const SkVertices* vertices, const SkMatrix* bones, int boneCount, SkBlendMode mode,
                  const SkPaint& paint)
Draws Vertices vertices, a triangle mesh, using Clip and Matrix. Bone data is used to deform vertices with bone weights. If Vertices Texs and Vertices Colors are defined in vertices, and Paint paint contains Shader, Blend Mode mode combines Vertices Colors with Shader. The first element of bones should be an object to world space transformation matrix that will be applied before performing mesh deformations. If no such transformation is needed, it should be the identity matrix. boneCount must be at most 100, and thus the size of bones should be at most 100. ### Parameters
vertices triangle mesh to draw
bones bone matrix data
boneCount number of bone matrices
mode combines Vertices Colors with Shader, if both are present
paint specifies the Shader, used as Vertices texture, may be nullptr
### Example
### See Also drawPatch[2] drawPicture[2][3][4] --- 
void drawVertices(const sk sp<SkVertices>& vertices, const SkMatrix* bones, int boneCount,
                  SkBlendMode mode, const SkPaint& paint)
Draws Vertices vertices, a triangle mesh, using Clip and Matrix. Bone data is used to deform vertices with bone weights. If Vertices Texs and Vertices Colors are defined in vertices, and Paint paint contains Shader, Blend Mode mode combines Vertices Colors with Shader. The first element of bones should be an object to world space transformation matrix that will be applied before performing mesh deformations. If no such transformation is needed, it should be the identity matrix. boneCount must be at most 100, and thus the size of bones should be at most 100. ### Parameters
vertices triangle mesh to draw
bones bone matrix data
boneCount number of bone matrices
mode combines Vertices Colors with Shader, if both are present
paint specifies the Shader, used as Vertices texture, may be nullptr
### Example
### See Also drawPatch[2] drawPicture[2][3][4] --- ## drawPatch 
void drawPatch(const SkPoint cubics[12], const SkColor colors[4], const SkPoint texCoords[4],
               SkBlendMode mode, const SkPaint& paint)
Draws a Coons Patch: the interpolation of four cubics with shared corners, associating a color, and optionally a texture Point, with each corner. Coons Patch uses Clip and Matrix, paint Shader, Color Filter, Color Alpha, Image Filter, and Blend Mode. If Shader is provided it is treated as Coons Patch texture; Blend Mode mode combines Color colors and Shader if both are provided. Point array cubics specifies four Cubics starting at the top-left corner, in clockwise order, sharing every fourth point. The last Cubic ends at the first point. Color array color associates colors with corners in top-left, top-right, bottom-right, bottom-left order. If paint contains Shader, Point array texCoords maps Shader as texture to corners in top-left, top-right, bottom-right, bottom-left order. ### Parameters #
cubics Path Cubic array, sharing common points
colors Color array, one for each corner
texCoords Point array of texture coordinates, mapping Shader to corners; may be nullptr
mode Blend Mode for colors, and for Shader if paint has one
paint Shader, Color Filter, Blend Mode, used to draw
### Example
### See Also SeeAlso drawVertices[2][3][4] drawPicture[2][3][4] --- 
void drawPatch(const SkPoint cubics[12], const SkColor colors[4], const SkPoint texCoords[4],
               const SkPaint& paint)
Draws Cubic Coons Patch: the interpolation of four cubics with shared corners, associating a color, and optionally a texture Point, with each corner. Coons Patch uses Clip and Matrix, paint Shader, Color Filter, Color Alpha, Image Filter, and Blend Mode. If Shader is provided it is treated as Coons Patch texture; Blend Mode mode combines Color colors and Shader if both are provided. Point array cubics specifies four Cubics starting at the top-left corner, in clockwise order, sharing every fourth point. The last Cubic ends at the first point. Color array color associates colors with corners in top-left, top-right, bottom-right, bottom-left order. If paint contains Shader, Point array texCoords maps Shader as texture to corners in top-left, top-right, bottom-right, bottom-left order. ### Parameters #
cubics Path Cubic array, sharing common points
colors Color array, one for each corner
texCoords Point array of texture coordinates, mapping Shader to corners; may be nullptr
paint Shader, Color Filter, Blend Mode, used to draw
### Example
### Example
### See Also SeeAlso drawVertices[2][3][4] drawPicture[2][3][4] --- ## drawAtlas 
void drawAtlas(const SkImage* atlas, const SkRSXform xform[], const SkRect tex[],
               const SkColor colors[], int count, SkBlendMode mode, const SkRect* cullRect,
               const SkPaint* paint)
Draws a set of sprites from atlas, using Clip, Matrix, and optional Paint paint. paint uses Anti Alias, Color Alpha, Color Filter, Image Filter, and Blend Mode to draw, if present. For each entry in the array, Rect tex locates sprite in atlas, and RSXform xform transforms it into destination space. xform, text, and colors if present, must contain count entries. Optional colors are applied for each sprite using Blend Mode mode, treating sprite as source and colors as destination. Optional cullRect is a conservative bounds of all transformed sprites. If cullRect is outside of Clip, canvas can skip drawing. ### Parameters
atlas Image containing sprites
xform RSXform mappings for sprites in atlas
tex Rect locations of sprites in atlas
colors one per sprite, blended with sprite using Blend Mode; may be nullptr
count number of sprites to draw
mode Blend Mode combining colors and sprites
cullRect bounds of transformed sprites for efficient clipping; may be nullptr
paint Color Filter, Image Filter, Blend Mode, and so on; may be nullptr
### Example
### See Also drawBitmap drawImage[2] --- 
void drawAtlas(const sk sp<SkImage>& atlas, const SkRSXform xform[], const SkRect tex[],
               const SkColor colors[], int count, SkBlendMode mode, const SkRect* cullRect,
               const SkPaint* paint)
Draws a set of sprites from atlas, using Clip, Matrix, and optional Paint paint. paint uses Anti Alias, Color Alpha, Color Filter, Image Filter, and Blend Mode to draw, if present. For each entry in the array, Rect tex locates sprite in atlas, and RSXform xform transforms it into destination space. xform, text, and colors if present, must contain count entries. Optional colors is applied for each sprite using Blend Mode. Optional cullRect is a conservative bounds of all transformed sprites. If cullRect is outside of Clip, canvas can skip drawing. ### Parameters
atlas Image containing sprites
xform RSXform mappings for sprites in atlas
tex Rect locations of sprites in atlas
colors one per sprite, blended with sprite using Blend Mode; may be nullptr
count number of sprites to draw
mode Blend Mode combining colors and sprites
cullRect bounds of transformed sprites for efficient clipping; may be nullptr
paint Color Filter, Image Filter, Blend Mode, and so on; may be nullptr
### Example
### See Also drawBitmap drawImage[2] --- 
void drawAtlas(const SkImage* atlas, const SkRSXform xform[], const SkRect tex[], int count,
               const SkRect* cullRect, const SkPaint* paint)
Draws a set of sprites from atlas, using Clip, Matrix, and optional Paint paint. paint uses Anti Alias, Color Alpha, Color Filter, Image Filter, and Blend Mode to draw, if present. For each entry in the array, Rect tex locates sprite in atlas, and RSXform xform transforms it into destination space. xform and text must contain count entries. Optional cullRect is a conservative bounds of all transformed sprites. If cullRect is outside of Clip, canvas can skip drawing. ### Parameters
atlas Image containing sprites
xform RSXform mappings for sprites in atlas
tex Rect locations of sprites in atlas
count number of sprites to draw
cullRect bounds of transformed sprites for efficient clipping; may be nullptr
paint Color Filter, Image Filter, Blend Mode, and so on; may be nullptr
### Example
### See Also drawBitmap drawImage[2] --- 
void drawAtlas(const sk sp<SkImage>& atlas, const SkRSXform xform[], const SkRect tex[], int count,
               const SkRect* cullRect, const SkPaint* paint)
Draws a set of sprites from atlas, using Clip, Matrix, and optional Paint paint. paint uses Anti Alias, Color Alpha, Color Filter, Image Filter, and Blend Mode to draw, if present. For each entry in the array, Rect tex locates sprite in atlas, and RSXform xform transforms it into destination space. xform and text must contain count entries. Optional cullRect is a conservative bounds of all transformed sprites. If cullRect is outside of Clip, canvas can skip drawing. ### Parameters
atlas Image containing sprites
xform RSXform mappings for sprites in atlas
tex Rect locations of sprites in atlas
count number of sprites to draw
cullRect bounds of transformed sprites for efficient clipping; may be nullptr
paint Color Filter, Image Filter, Blend Mode, and so on; may be nullptr
### Example
### See Also drawBitmap drawImage[2] --- ## drawDrawable 
void drawDrawable(SkDrawable* drawable, const SkMatrix* matrix = nullptr)
Draws Drawable drawable using Clip and Matrix, concatenated with optional matrix. If Canvas has an asynchronous implementation, as is the case when it is recording into Picture, then drawable will be referenced, so that SkDrawable::draw() can be called when the operation is finalized. To force immediate drawing, call SkDrawable::draw() instead. ### Parameters
drawable custom struct encapsulating drawing commands
matrix transformation applied to drawing; may be nullptr
### Example
### See Also SkDrawable drawPicture[2][3][4] --- 
void drawDrawable(SkDrawable* drawable, SkScalar x, SkScalar y)
Draws Drawable drawable using Clip and Matrix, offset by (x, y). If Canvas has an asynchronous implementation, as is the case when it is recording into Picture, then drawable will be referenced, so that SkDrawable::draw() can be called when the operation is finalized. To force immediate drawing, call SkDrawable::draw() instead. ### Parameters
drawable custom struct encapsulating drawing commands
x offset into Canvas writable pixels on x-axis
y offset into Canvas writable pixels on y-axis
### Example
### See Also SkDrawable drawPicture[2][3][4] --- ## drawAnnotation 
void drawAnnotation(const SkRect& rect, const char key[], SkData* value)
Associates Rect on Canvas with an annotation; a key-value pair, where the key is a null-terminated utf8 string, and optional value is stored as Data. Only some canvas implementations, such as recording to Picture, or drawing to Document PDF, use annotations. ### Parameters
rect Rect extent of canvas to annotate
key string used for lookup
value data holding value stored in annotation
### Example
### See Also SkPicture SkDocument --- 
void drawAnnotation(const SkRect& rect, const char key[], const sk sp<SkData>& value)
Associates Rect on Canvas when an annotation; a key-value pair, where the key is a null-terminated utf8 string, and optional value is stored as Data. Only some canvas implementations, such as recording to Picture, or drawing to Document PDF, use annotations. ### Parameters
rect Rect extent of canvas to annotate
key string used for lookup
value data holding value stored in annotation
### Example
### See Also SkPicture SkDocument --- ## isClipEmpty 
virtual bool isClipEmpty() const
Returns true if Clip is empty; that is, nothing will draw. May do work when called; it should not be called more often than needed. However, once called, subsequent calls perform no work until Clip changes. ### Return Value true if Clip is empty ### Example
#### Example Output ~~~~ clip is not empty clip is empty ~~~~
### See Also isClipRect getLocalClipBounds[2] getDeviceClipBounds[2] --- ## isClipRect 
virtual bool isClipRect() const
Returns true if Clip is Rect and not empty. Returns false if the clip is empty, or if it is not Rect. ### Return Value true if Clip is Rect and not empty ### Example
#### Example Output ~~~~ clip is rect clip is not rect ~~~~
### See Also isClipEmpty getLocalClipBounds[2] getDeviceClipBounds[2] ---