SkSurface is responsible for managing the pixels that a canvas draws into. The pixels can be allocated either in CPU memory, if a raster surface; or on the GPU, for a GrRenderTarget surface. SkSurface takes care of allocating a SkCanvas that will draw into the surface. Call surface->getCanvas() to use that canvas. The caller should not delete the returned canvas; it is owned by surface.
SkSurface always has non-zero dimensions. If there is a request for a new surface, and either of the requested dimensions are zero, then nullptr will be returned.
Allocates raster SkSurface. SkCanvas returned by SkSurface draws directly into pixels.
SkSurface is returned if all parameters are valid. Valid parameters include: info dimensions are greater than zero; info contains SkColorType and SkAlphaType supported by raster surface; pixels is not nullptr; rowBytes is large enough to contain info width pixels of SkColorType.
Pixel buffer size should be info height times computed rowBytes. Pixels are not initialized. To access pixels after drawing, call flush() or peekPixels().
of raster surface; width and height must be greater than zero
may be nullptr
SkSurface if all parameters are valid; otherwise, nullptr
--- -x- ---
MakeRasterDirectReleaseProc MakeRaster MakeRasterN32Premul SkCanvas::MakeRasterDirect
Allocates raster SkSurface. SkCanvas returned by SkSurface draws directly into pixels. releaseProc is called with pixels and context when SkSurface is deleted.
SkSurface is returned if all parameters are valid. Valid parameters include: info dimensions are greater than zero; info contains SkColorType and SkAlphaType supported by raster surface; pixels is not nullptr; rowBytes is large enough to contain info width pixels of SkColorType.
Pixel buffer size should be info height times computed rowBytes. Pixels are not initialized. To access pixels after drawing, call flush() or peekPixels().
of raster surface; width and height must be greater than zero
may be nullptr
SkSurface if all parameters are valid; otherwise, nullptr
--- -x- --- expected release context
MakeRasterDirect MakeRasterN32Premul MakeRaster
Allocates raster SkSurface. SkCanvas returned by SkSurface draws directly into pixels. Allocates and zeroes pixel memory. Pixel memory size is imageInfo.height() times rowBytes, or times imageInfo.minRowBytes() if rowBytes is zero. Pixel memory is deleted when SkSurface is deleted.
SkSurface is returned if all parameters are valid. Valid parameters include: info dimensions are greater than zero; info contains SkColorType and SkAlphaType supported by raster surface; rowBytes is large enough to contain info width pixels of SkColorType, or is zero.
If rowBytes is not zero, subsequent images returned by makeImageSnapshot() have the same rowBytes.
of raster surface; width and height must be greater than zero
may be nullptr
SkSurface if all parameters are valid; otherwise, nullptr
--- -x- ---
MakeRasterDirect MakeRasterN32Premul MakeRasterDirectReleaseProc
Allocates raster SkSurface. SkCanvas returned by SkSurface draws directly into pixels. Allocates and zeroes pixel memory. Pixel memory size is imageInfo.height() times imageInfo.minRowBytes(). Pixel memory is deleted when SkSurface is deleted.
SkSurface is returned if all parameters are valid. Valid parameters include: info dimensions are greater than zero; info contains SkColorType and SkAlphaType supported by raster surface.
of raster surface; width and height must be greater than zero
may be nullptr
SkSurface if all parameters are valid; otherwise, nullptr
MakeRasterDirect MakeRasterN32Premul MakeRasterDirectReleaseProc
Allocates raster SkSurface. SkCanvas returned by SkSurface draws directly into pixels. Allocates and zeroes pixel memory. Pixel memory size is height times width times four. Pixel memory is deleted when SkSurface is deleted.
Internally, sets SkImageInfo to width, height, native color type, and kPremul_SkAlphaType.
SkSurface is returned if width and height are greater than zero.
Use to create SkSurface that matches SkPMColor, the native pixel arrangement on the platform. SkSurface drawn to output device skips converting its pixel format.
fonts; may be nullptr
SkSurface if all parameters are valid; otherwise, nullptr
--- -x- ---
MakeRasterDirect MakeRasterN32Premul MakeRasterDirectReleaseProc
Wraps a GPU-backed texture into SkSurface. Caller must ensure the texture is valid for the lifetime of returned SkSurface. If sampleCnt greater than zero, creates an intermediate MSAA SkSurface which is used for drawing backendTexture.
SkSurface is returned if all parameters are valid. backendTexture is valid if its pixel configuration agrees with colorSpace and context; for instance, if backendTexture has an sRGB configuration, then context must support sRGB, and colorSpace must be present. Further, backendTexture width and height must not exceed context capabilities, and the context must be able to support back-end textures.
If SK_SUPPORT_GPU is defined as zero, has no effect and returns nullptr.
kUnknown_SkColorType, kAlpha_8_SkColorType, kRGB_565_SkColorType, kARGB_4444_SkColorType, kRGBA_8888_SkColorType, kRGB_888x_SkColorType, kBGRA_8888_SkColorType, kRGBA_1010102_SkColorType, kRGB_101010x_SkColorType, kGray_8_SkColorType, kRGBA_F16_SkColorType
fonts; may be nullptr
SkSurface if all parameters are valid; otherwise, nullptr
GrBackendTexture MakeFromBackendRenderTarget MakeRenderTarget
Wraps a GPU-backed buffer into SkSurface. Caller must ensure backendRenderTarget is valid for the lifetime of returned SkSurface.
SkSurface is returned if all parameters are valid. backendRenderTarget is valid if its pixel configuration agrees with colorSpace and context; for instance, if backendRenderTarget has an sRGB configuration, then context must support sRGB, and colorSpace must be present. Further, backendRenderTarget width and height must not exceed context capabilities, and the context must be able to support back-end render targets.
If SK_SUPPORT_GPU is defined as zero, has no effect and returns nullptr.
kUnknown_SkColorType, kAlpha_8_SkColorType, kRGB_565_SkColorType, kARGB_4444_SkColorType, kRGBA_8888_SkColorType, kRGB_888x_SkColorType, kBGRA_8888_SkColorType, kRGBA_1010102_SkColorType, kRGB_101010x_SkColorType, kGray_8_SkColorType, kRGBA_F16_SkColorType
fonts; may be nullptr
SkSurface if all parameters are valid; otherwise, nullptr
MakeFromBackendTexture MakeRenderTarget
Wraps a GPU-backed texture into SkSurface. Caller must ensure backendTexture is valid for the lifetime of returned SkSurface. If sampleCnt greater than zero, creates an intermediate MSAA SkSurface which is used for drawing backendTexture.
SkSurface is returned if all parameters are valid. backendTexture is valid if its pixel configuration agrees with colorSpace and context; for instance, if backendTexture has an sRGB configuration, then context must support sRGB, and colorSpace must be present. Further, backendTexture width and height must not exceed context capabilities.
Returned SkSurface is available only for drawing into, and cannot generate an SkImage.
If SK_SUPPORT_GPU is defined as zero, has no effect and returns nullptr.
kUnknown_SkColorType, kAlpha_8_SkColorType, kRGB_565_SkColorType, kARGB_4444_SkColorType, kRGBA_8888_SkColorType, kRGB_888x_SkColorType, kBGRA_8888_SkColorType, kRGBA_1010102_SkColorType, kRGB_101010x_SkColorType, kGray_8_SkColorType, kRGBA_F16_SkColorType
fonts; may be nullptr
SkSurface if all parameters are valid; otherwise, nullptr
MakeFromBackendRenderTarget MakeRenderTarget
Returns SkSurface on GPU indicated by context. Allocates memory for pixels, based on the width, height, and SkColorType in SkImageInfo. budgeted selects whether allocation for pixels is tracked by context. imageInfo describes the pixel format in SkColorType, and transparency in SkAlphaType, and color matching in SkColorSpace.
sampleCount requests the number of samples per pixel. Pass zero to disable multi-sample anti-aliasing. The request is rounded up to the next supported count, or rounded down if it is larger than the maximum supported count.
surfaceOrigin pins either the top-left or the bottom-left corner to the origin.
shouldCreateWithMips hints that SkImage returned by makeImageSnapshot() is mip map.
If SK_SUPPORT_GPU is defined as zero, has no effect and returns nullptr.
width, or height, or both, may be zero
fonts; may be nullptr
SkSurface if all parameters are valid; otherwise, nullptr
MakeFromBackendRenderTarget MakeFromBackendTextureAsRenderTarget
Returns SkSurface on GPU indicated by context. Allocates memory for pixels, based on the width, height, and SkColorType in SkImageInfo. budgeted selects whether allocation for pixels is tracked by context. imageInfo describes the pixel format in SkColorType, and transparency in SkAlphaType, and color matching in SkColorSpace.
sampleCount requests the number of samples per pixel. Pass zero to disable multi-sample anti-aliasing. The request is rounded up to the next supported count, or rounded down if it is larger than the maximum supported count.
SkSurface bottom-left corner is pinned to the origin.
of raster surface; width, or height, or both, may be zero
fonts; may be nullptr
SkSurface if all parameters are valid; otherwise, nullptr
MakeFromBackendRenderTarget MakeFromBackendTextureAsRenderTarget
Returns SkSurface on GPU indicated by context. Allocates memory for pixels, based on the width, height, and SkColorType in SkImageInfo. budgeted selects whether allocation for pixels is tracked by context. imageInfo describes the pixel format in SkColorType, and transparency in SkAlphaType, and color matching in SkColorSpace.
SkSurface bottom-left corner is pinned to the origin.
of raster surface; width, or height, or both, may be zero
SkSurface if all parameters are valid; otherwise, nullptr
MakeFromBackendRenderTarget MakeFromBackendTextureAsRenderTarget
Returns SkSurface on GPU indicated by context that is compatible with the provided characterization. budgeted selects whether allocation for pixels is tracked by context.
SkSurface if all parameters are valid; otherwise, nullptr
MakeFromBackendRenderTarget MakeFromBackendTextureAsRenderTarget
Returns SkSurface without backing pixels. Drawing to SkCanvas returned from SkSurface has no effect. Calling makeImageSnapshot() on returned SkSurface returns nullptr.
SkSurface if width and height are positive; otherwise, nullptr
SkSurface::MakeNull(0, 0) == nullptr surf->makeImageSnapshot() == nullptr
MakeRaster MakeRenderTarget
Returns pixel count in each row; may be zero or greater.
number of pixel columns
surface width=37 canvas width=37
height()
Returns pixel row count; may be zero or greater.
number of pixel rows
surface height=1000 canvas height=1000
width()
Returns unique value identifying the content of SkSurface. Returned value changes each time the content changes. Content is changed by drawing, or by calling notifyContentWillChange().
unique content identifier
surface generationID: 1 surface generationID: 2 surface generationID: 3
notifyContentWillChange ContentChangeMode getCanvas
ContentChangeMode members are parameters to notifyContentWillChange.
notifyContentWillChange generationID
Notifies that SkSurface contents will be changed by code outside of Skia. Subsequent calls to generationID() return a different value.
ContentChangeMode generationID
getBackendTexture getBackendRenderTarget
Retrieves the back-end texture. If SkSurface has no back-end texture, an invalid object is returned. Call GrBackendTexture::isValid to determine if the result is valid.
The returned GrBackendTexture should be discarded if the SkSurface is drawn to or deleted.
kFlushWrite_BackendHandleAccess, kDiscardWrite_BackendHandleAccess
GPU texture reference; invalid on failure
GrBackendTexture BackendHandleAccess getBackendRenderTarget
Retrieves the back-end render target. If SkSurface has no back-end render target, an invalid object is returned. Call GrBackendRenderTarget::isValid to determine if the result is valid.
The returned GrBackendRenderTarget should be discarded if the SkSurface is drawn to or deleted.
kFlushWrite_BackendHandleAccess, kDiscardWrite_BackendHandleAccess
GPU render target reference; invalid on failure
GrBackendRenderTarget BackendHandleAccess getBackendTexture
Returns SkCanvas that draws into SkSurface. Subsequent calls return the same SkCanvas. SkCanvas returned is managed and owned by SkSurface, and is deleted when SkSurface is deleted.
drawing SkCanvas for SkSurface
makeSurface makeImageSnapshot draw
Returns a compatible SkSurface, or nullptr. Returned SkSurface contains the same raster, GPU, or null properties as the original. Returned SkSurface does not share the same pixels.
Returns nullptr if imageInfo width or height are zero, or if imageInfo is incompatible with SkSurface.
of SkSurface; width and height must be greater than zero
compatible SkSurface or nullptr
makeImageSnapshot getCanvas draw
Returns SkImage capturing SkSurface contents. Subsequent drawing to SkSurface contents are not captured. SkImage allocation is accounted for if SkSurface was created with SkBudgeted::kYes.
SkImage initialized with SkSurface contents
draw getCanvas
Like the no-parameter version, this returns an image of the current surface contents. This variant takes a rectangle specifying the subset of the surface that is of interest. These bounds will be sanitized before being used.
draw getCanvas
Draws SkSurface contents to canvas, with its top-left corner at (x, y).
If SkPaint paint is not nullptr, apply SkColorFilter, alpha, SkImageFilter, SkBlendMode, and SkDrawLooper.
and so on; or nullptr
makeImageSnapshot getCanvas
Copies SkSurface pixel address, row bytes, and SkImageInfo to SkPixmap, if address is available, and returns true. If pixel address is not available, return false and leave SkPixmap unchanged.
pixmap contents become invalid on any future change to SkSurface.
true if SkSurface has direct access to pixels
readPixels writePixels
Copies Rect of pixels to dst.
Source Rect corners are (srcX, srcY) and Surface (width(), height()). Destination Rect corners are (0, 0) and (dst.width(), dst.height()). Copies each readable pixel intersecting both rectangles, without scaling, converting to dst.colorType() and dst.alphaType() if required.
Pixels are readable when Surface is raster, or backed by a GPU.
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. dst 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:
true if pixels were copied
peekPixels writePixels
Copies Rect of pixels from Canvas into dstPixels.
Source Rect corners are (srcX, srcY) and Surface (width(), 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 Surface is raster, or backed by a GPU.
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:
true if pixels were copied
peekPixels writePixels
Copies Rect of pixels from Surface into bitmap.
Source Rect corners are (srcX, srcY) and Surface (width(), height()). Destination Rect corners are (0, 0) and (bitmap.width(), bitmap.height()). Copies each readable pixel intersecting both rectangles, without scaling, converting to dst.colorType() and dst.alphaType() if required.
Pixels are readable when Surface is raster, or backed by a GPU.
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. dst 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:
true if pixels were copied
peekPixels writePixels
Copies Rect of pixels from the src Pixmap to the Surface.
Source Rect corners are (0, 0) and (src.width(), src.height()). Destination Rect corners are (dstX, dstY) and (dstX + Surface width(), dstY + Surface height()).
Copies each readable pixel intersecting both rectangles, without scaling, converting to Surface SkColorType and SkAlphaType if required.
readPixels peekPixels
Copies Rect of pixels from the src Bitmap to the Surface.
Source Rect corners are (0, 0) and (src.width(), src.height()). Destination Rect corners are (dstX, dstY) and (dstX + Surface width(), dstY + Surface height()).
Copies each readable pixel intersecting both rectangles, without scaling, converting to Surface SkColorType and SkAlphaType if required.
readPixels peekPixels
Returns SkSurfaceProps for surface.
LCD striping orientation and setting for device independent fonts
surf.props(): kRGB_H_SkPixelGeometry
SkSurfaceProps
Issues pending SkSurface commands to the GPU-backed API and resolves any SkSurface MSAA.
Skia flushes as needed, so it is not necessary to call this if Skia manages drawing and object lifetime. Call when interleaving Skia calls with native GPU calls.
GrBackendSemaphore
Issues pending SkSurface commands to the GPU-backed API and resolves any SkSurface MSAA. After issuing all commands, signalSemaphores of count numSemaphores semaphores are signaled by the GPU.
For each GrBackendSemaphore in signalSemaphores: if GrBackendSemaphore is initialized, the GPU back-end uses the semaphore as is; otherwise, a new semaphore is created and initializes GrBackendSemaphore.
The caller must delete the semaphores created and returned in signalSemaphores. GrBackendSemaphore can be deleted as soon as this function returns.
If the back-end API is OpenGL only uninitialized backend semaphores are supported.
If the back-end API is Vulkan semaphores may be initialized or uninitialized. If uninitialized, created semaphores are valid only with the VkDevice with which they were created.
If GrSemaphoresSubmitted::kNo is returned, the GPU back-end did not create or add any semaphores to signal on the GPU; the caller should not instruct the GPU to wait on any of the semaphores.
Pending surface commands are flushed regardless of the return result.
one of: GrSemaphoresSubmitted::kYes, GrSemaphoresSubmitted::kNo
wait GrBackendSemaphore
Inserts a list of GPU semaphores that the current GPU-backed API must wait on before executing any more commands on the GPU for this surface. Skia will take ownership of the underlying semaphores and delete them once they have been signaled and waited on. If this call returns false, then the GPU back-end will not wait on any passed in semaphores, and the client will still own the semaphores.
true if GPU is waiting on semaphores
flushAndSignalSemaphores GrBackendSemaphore
Initializes SkSurfaceCharacterization that can be used to perform GPU back-end processing in a separate thread. Typically this is used to divide drawing into multiple tiles. SkDeferredDisplayListRecorder records the drawing commands for each tile.
Return true if SkSurface supports characterization. raster surface returns false.
true if supported
draw() SkSurfaceCharacterization SkDeferredDisplayList
Draws deferred display list created using SkDeferredDisplayListRecorder. Has no effect and returns false if SkSurfaceCharacterization stored in deferredDisplayList is not compatible with SkSurface.
raster surface returns false.
false if deferredDisplayList is not compatible
characterize() SkSurfaceCharacterization SkDeferredDisplayList