SkImage Reference

Image

Overview

Overview Subtopic

namedescription
Constantenum and enum class, const values
Constructorfunctions that construct SkImage
Member Functionstatic functions and member methods
Related Functionsimilar methods grouped together

Class SkImage

Image describes a two dimensional array of pixels to draw. The pixels may be decoded in a Raster Bitmap, encoded in a Picture or compressed data stream, or located in GPU memory as a GPU Texture.

Image cannot be modified after it is created. Image may allocate additional storage as needed; for instance, an encoded Image may decode when drawn.

Image width and height are greater than zero. Creating an Image with zero width or height returns Image equal to nullptr.

Image may be created from Bitmap, Pixmap, Surface, Picture, encoded streams, GPU Texture, YUV ColorSpace data, or hardware buffer. Encoded streams supported include BMP, GIF, HEIF, ICO, JPEG, PNG, WBMP, WebP. Supported encoding details vary with platform.

Raster Image

Raster Image pixels are decoded in a Raster Bitmap. These pixels may be read directly and in most cases written to, although edited pixels may not be drawn if Image has been copied internally.

Texture Image

Texture Image are located on GPU and pixels are not accessible. Texture Image are allocated optimally for best performance. Raster Image may be drawn to GPU Surface, but pixels are uploaded from CPU to GPU downgrading performance.

Lazy Image

Lazy Image defer allocating buffer for Image pixels and decoding stream until Image is drawn. Lazy Image caches result if possible to speed up repeated drawing.

Related Function

namedescription
Lazy Imagedeferred pixel buffer
Pixelsread and write pixel values
Propertyvalues and attributes
Raster Imagepixels decoded in Raster Bitmap
Texture Imagepixels located on GPU
Utilityrarely called management functions

Class or Struct

namedescription

Constructor

namedescription
MakeBackendTextureFromSkImagecreates GPU Texture from Image
MakeCrossContextFromEncodedcreates Image from encoded data, and uploads to GPU
MakeCrossContextFromPixmapcreates Image from Pixmap, and uploads to GPU
MakeFromAHardwareBuffercreates Image from Android hardware buffer
MakeFromAdoptedTexture 2creates Image from GPU Texture, managed internally
MakeFromBitmapcreates Image from Bitmap, sharing or copying pixels
MakeFromEncodedcreates Image from encoded data
MakeFromGeneratorcreates Image from a stream of data
MakeFromNV12TexturesCopycreates Image from YUV ColorSpace data in two planes
MakeFromNV12TexturesCopy(GrContext* context, SkYUVColorSpace yuvColorSpace, const GrBackendObject nv12TextureHandles[2], const SkISize nv12Sizes[2], GrSurfaceOrigin surfaceOrigin, sk sp<SkColorSpace> colorSpace = nullptr)
MakeFromNV12TexturesCopy(GrContext* context, SkYUVColorSpace yuvColorSpace, const GrBackendTexture nv12TextureHandles[2], const SkISize nv12Sizes[2], GrSurfaceOrigin surfaceOrigin, sk sp<SkColorSpace> colorSpace = nullptr)
MakeFromPicturecreates Image from Picture
MakeFromRastercreates Image from Pixmap, with release
MakeFromTexture 3creates Image from GPU Texture
static sk sp<SkImage> MakeFromTexture(GrContext* context, const GrBackendTexture& backendTexture, GrSurfaceOrigin origin, SkColorType colorType, SkAlphaType alphaType, sk sp<SkColorSpace> colorSpace)
MakeFromYUVTexturesCopycreates Image from YUV ColorSpace data in three planes
MakeFromYUVTexturesCopy(GrContext* context, SkYUVColorSpace yuvColorSpace, const GrBackendObject yuvTextureHandles[3], const SkISize yuvSizes[3], GrSurfaceOrigin surfaceOrigin, sk sp<SkColorSpace> colorSpace = nullptr)
MakeFromYUVTexturesCopy(GrContext* context, SkYUVColorSpace yuvColorSpace, const GrBackendTexture yuvTextureHandles[3], const SkISize yuvSizes[3], GrSurfaceOrigin surfaceOrigin, sk sp<SkColorSpace> colorSpace = nullptr)
MakeRasterCopycreates Image from Pixmap and copied pixels
MakeRasterDatacreates Image from Image Info and shared pixels
asLegacyBitmapreturns as Raster Bitmap
makeColorSpacecreates Image matching Color Space if possible
makeNonTextureImagecreates Image without dependency on GPU Texture
makeRasterImagecreates Image compatible with Raster Surface if possible
makeShadercreates Shader, Paint element that can tile Image
makeShader(SkShader::TileMode tileMode1, SkShader::TileMode tileMode2, const SkMatrix* localMatrix = nullptr) const
makeShader(const SkMatrix* localMatrix = nullptr) const
makeSubsetcreates Image containing part of original
makeTextureImagecreates Image matching Color Space if possible
makeWithFiltercreates filtered, clipped Image

Member Function

namedescription
MakeBackendTextureFromSkImagecreates GPU Texture from Image
MakeCrossContextFromEncodedcreates Image from encoded data, and uploads to GPU
MakeCrossContextFromPixmapcreates Image from Pixmap, and uploads to GPU
MakeFromAHardwareBuffercreates Image from Android hardware buffer
MakeFromAdoptedTexture 2creates Image from GPU Texture, managed internally
MakeFromBitmapcreates Image from Bitmap, sharing or copying pixels
MakeFromEncodedcreates Image from encoded data
MakeFromGeneratorcreates Image from a stream of data
MakeFromNV12TexturesCopycreates Image from YUV ColorSpace data in two planes
MakeFromPicturecreates Image from Picture
MakeFromRastercreates Image from Pixmap, with release
MakeFromTexture 3creates Image from GPU Texture
MakeFromYUVTexturesCopycreates Image from YUV ColorSpace data in three planes
MakeRasterCopycreates Image from Pixmap and copied pixels
MakeRasterDatacreates Image from Image Info and shared pixels
alphaTypereturns Alpha Type
asLegacyBitmapreturns as Raster Bitmap
boundsreturns width and height as Rectangle
colorSpacereturns Color Space
dimensionsreturns width and height
encodeToDatareturns encoded Image as SkData
getTextureHandlereturns GPU reference to Image as texture
heightreturns pixel row count
isAlphaOnlyreturns if pixels represent a transparency mask
isLazyGeneratedreturns if Image is created as needed
isOpaquereturns if Alpha Type is kOpaque_SkAlphaType
isTextureBackedreturns if Image was created from GPU Texture
isValidreturns if Image can draw to Raster Surface or GPU Context
makeColorSpacecreates Image matching Color Space if possible
makeNonTextureImagecreates Image without dependency on GPU Texture
makeRasterImagecreates Image compatible with Raster Surface if possible
makeShadercreates Shader, Paint element that can tile Image
makeSubsetcreates Image containing part of original
makeTextureImagecreates Image matching Color Space if possible
makeWithFiltercreates filtered, clipped Image
peekPixelsreturns Pixmap if possible
readPixelscopies and converts pixels
refColorSpacereturns Image Info Color Space
refEncodedDatareturns Image encoded in SkData if present
scalePixelsscales and converts one Image to another
toStringconverts Image to machine readable form
uniqueIDidentifier for Image
widthreturns pixel column count

MakeRasterCopy

Creates Image from Pixmap and copy of pixels. Since pixels are copied, Pixmap pixels may be modified or deleted without affecting Image.

Image is returned if Pixmap is valid. Valid Pixmap parameters include: dimensions are greater than zero; each dimension fits in 29 bits; Color Type and Alpha Type are valid, and Color Type is not kUnknown_SkColorType; row bytes are large enough to hold one row of pixels; pixel address is not nullptr.

Parameters

Return Value

copy of Pixmap pixels, or nullptr

Example

See Also

MakeRasterData MakeFromGenerator


MakeRasterData

Creates Image from Image Info, sharing pixels.

Image is returned if Image Info is valid. Valid Image Info parameters include: dimensions are greater than zero; each dimension fits in 29 bits; Color Type and Alpha Type are valid, and Color Type is not kUnknown_SkColorType; rowBytes are large enough to hold one row of pixels; pixels is not nullptr, and contains enough data for Image.

Parameters

Return Value

Image sharing pixels, or nullptr

Example

See Also

MakeRasterCopy MakeFromGenerator


Caller data passed to RasterReleaseProc; may be nullptr.

See Also

MakeFromRaster RasterReleaseProc

Function called when Image no longer shares pixels. ReleaseContext is provided by caller when Image is created, and may be nullptr.

See Also

ReleaseContext MakeFromRaster

MakeFromRaster

Creates Image from pixmap, sharing Pixmap pixels. Pixels must remain valid and unchanged until rasterReleaseProc is called. rasterReleaseProc is passed releaseContext when Image is deleted or no longer refers to pixmap pixels.

Pass nullptr for rasterReleaseProc to share Pixmap without requiring a callback when Image is released. Pass nullptr for releaseContext if rasterReleaseProc does not require state.

Image is returned if pixmap is valid. Valid Pixmap parameters include: dimensions are greater than zero; each dimension fits in 29 bits; Color Type and Alpha Type are valid, and Color Type is not kUnknown_SkColorType; row bytes are large enough to hold one row of pixels; pixel address is not nullptr.

Parameters

Return Value

Image sharing pixmap

Example

Example Output

before reset: 0
after reset: 1

See Also

MakeRasterCopy MakeRasterData MakeFromGenerator RasterReleaseProc ReleaseContext


MakeFromBitmap

Creates Image from bitmap, sharing or copying bitmap pixels. If the bitmap is marked immutable, and its pixel memory is shareable, it may be shared instead of copied.

Image is returned if bitmap is valid. Valid Bitmap parameters include: dimensions are greater than zero; each dimension fits in 29 bits; Color Type and Alpha Type are valid, and Color Type is not kUnknown_SkColorType; row bytes are large enough to hold one row of pixels; pixel address is not nullptr.

Parameters

Return Value

created Image, or nullptr

Example

See Also

MakeFromRaster MakeRasterCopy MakeFromGenerator MakeRasterData


MakeFromGenerator

Creates Image from data returned by imageGenerator. Generated data is owned by Image and may not be shared or accessed.

subset allows selecting a portion of the full image. Pass nullptr to select the entire image; otherwise, subset must be contained by image bounds.

Image is returned if generator data is valid. Valid data parameters vary by type of data and platform.

imageGenerator may wrap Picture data, codec data, or custom data.

Parameters

Return Value

created Image, or nullptr

Example

See Also

MakeFromEncoded


MakeFromEncoded

Creates Image from encoded data. subset allows selecting a portion of the full image. Pass nullptr to select the entire image; otherwise, subset must be contained by image bounds.

Image is returned if format of the encoded data is recognized and supported. Recognized formats vary by platform.

Parameters

Return Value

created Image, or nullptr

Example

See Also

MakeFromGenerator




MakeFromTexture_3

Creates Image from GPU Texture associated with context. Caller is responsible for managing the lifetime of GPU Texture.

Image is returned if format of backendTexture is recognized and supported. Recognized formats vary by GPU back-end.

Parameters

Return Value

created Image, or nullptr

Example

See Also

MakeFromAdoptedTexture SkSurface::MakeFromBackendTexture[2]


Creates Image from GPU Texture associated with context. GPU Texture must stay valid and unchanged until textureReleaseProc is called. textureReleaseProc is passed releaseContext when Image is deleted or no longer refers to texture.

Image is returned if format of backendTexture is recognized and supported. Recognized formats vary by GPU back-end.

Parameters

Return Value

created Image, or nullptr

Example

See Also

MakeFromAdoptedTexture SkSurface::MakeFromBackendTexture[2]


MakeCrossContextFromEncoded

Creates Image from encoded data. Image is uploaded to GPU back-end using context.

Created Image is available to other GPU contexts, and is available across thread boundaries. All contexts must be in the same GPU_Share_Group, or otherwise share resources.

When Image is no longer referenced, context releases texture memory asynchronously.

Texture decoded from data is uploaded to match Surface created with dstColorSpace. Color Space of Image is determined by encoded data.

Image is returned if format of data is recognized and supported, and if context supports moving resources. Recognized formats vary by platform and GPU back-end.

Image is returned using MakeFromEncoded if context is nullptr or does not support moving resources between contexts.

Parameters

Return Value

created Image, or nullptr

Example

See Also

MakeCrossContextFromPixmap


MakeCrossContextFromPixmap

Creates Image from pixmap. Image is uploaded to GPU back-end using context.

Created Image is available to other GPU contexts, and is available across thread boundaries. All contexts must be in the same GPU_Share_Group, or otherwise share resources.

When Image is no longer referenced, context releases texture memory asynchronously.

Texture created from pixmap is uploaded to match Surface created with dstColorSpace. Color Space of Image is determined by pixmap.colorSpace.

Image is returned referring to GPU back-end if context is not nullptr, format of data is recognized and supported, and if context supports moving resources between contexts. Otherwise, pixmap pixel data is copied and Image as returned in raster format if possible; nullptr may be returned. Recognized GPU formats vary by platform and GPU back-end.

Parameters

Return Value

created Image, or nullptr

Example

See Also

MakeCrossContextFromEncoded



MakeFromAdoptedTexture_2

Creates Image from backendTexture associated with context. backendTexture and returned Image are managed internally, and are released when no longer needed.

Image is returned if format of backendTexture is recognized and supported. Recognized formats vary by GPU back-end.

Parameters

Return Value

created Image, or nullptr

Example

See Also

MakeFromTexture MakeFromYUVTexturesCopy[2]


MakeFromYUVTexturesCopy

Creates Image from copy of yuvTextureHandles, an array of textures on GPU. yuvTextureHandles contain pixels for YUV planes of Image. yuvSizes contain dimensions for each pixel plane. Dimensions must be greater than zero but may differ from plane to plane. Returned Image has the dimensions yuvSizes[0]. yuvColorSpace describes how YUV colors convert to RGB colors.

Parameters

Return Value

created Image, or nullptr

See Also

MakeFromNV12TexturesCopy[2]


Creates Image from copy of yuvTextureHandles, an array of textures on GPU. yuvTextureHandles contain pixels for YUV planes of Image. yuvSizes contain dimensions for each pixel plane. Dimensions must be greater than zero but may differ from plane to plane. Returned Image has the dimensions yuvSizes[0]. yuvColorSpace describes how YUV colors convert to RGB colors.

Parameters

Return Value

created Image, or nullptr

See Also

MakeFromNV12TexturesCopy[2]


MakeFromNV12TexturesCopy

Creates Image from copy of nv12TextureHandles, an array of textures on GPU. nv12TextureHandles[0] contains pixels for YUV_Component_Y plane. nv12TextureHandles[1] contains pixels for YUV_Component_U plane, followed by pixels for YUV_Component_V plane. nv12Sizes contain dimensions for each pixel plane. Dimensions must be greater than zero but may differ from plane to plane. Returned Image has the dimensions nv12Sizes[0]. yuvColorSpace describes how YUV colors convert to RGB colors.

Parameters

Return Value

created Image, or nullptr

See Also

MakeFromYUVTexturesCopy[2]


Creates Image from copy of nv12TextureHandles, an array of textures on GPU. nv12TextureHandles[0] contains pixels for YUV_Component_Y plane. nv12TextureHandles[1] contains pixels for YUV_Component_U plane, followed by pixels for YUV_Component_V plane. nv12Sizes contain dimensions for each pixel plane. Dimensions must be greater than zero but may differ from plane to plane. Returned Image has the dimensions nv12Sizes[0]. yuvColorSpace describes how YUV colors convert to RGB colors.

Parameters

Return Value

created Image, or nullptr

See Also

MakeFromYUVTexturesCopy[2]


Enum SkImage::BitDepth

Constants

See Also

MakeFromPicture

MakeFromPicture

Creates Image from picture. Returned Image width and height are set by dimensions. Image draws picture with matrix and paint, set to bitDepth and colorSpace.

If matrix is nullptr, draws with identity Matrix. If paint is nullptr, draws with default Paint. colorSpace may be nullptr.

Parameters

Return Value

created Image, or nullptr

Example

See Also

SkCanvas::drawPicture[2][3][4]


MakeFromAHardwareBuffer

Creates Image from Android hardware buffer. Returned Image takes a reference on the buffer.

Only available on Android, when ANDROID_API is defined to be 26 or greater.

Parameters

Return Value

created Image, or nullptr

See Also

MakeFromRaster


Property

namedescription
alphaTypereturns Alpha Type
boundsreturns width and height as Rectangle
colorSpacereturns Color Space
dimensionsreturns width and height
getTextureHandlereturns GPU reference to Image as texture
heightreturns pixel row count
isAlphaOnlyreturns if pixels represent a transparency mask
isLazyGeneratedreturns if Image is created as needed
isOpaquereturns if Alpha Type is kOpaque_SkAlphaType
isTextureBackedreturns if Image was created from GPU Texture
isValidreturns if Image can draw to Raster Surface or GPU Context
refColorSpacereturns Image Info Color Space
uniqueIDidentifier for Image
widthreturns pixel column count

width

Returns pixel count in each row.

Return Value

pixel width in Image

Example

See Also

dimensions height


height

Returns pixel row count.

Return Value

pixel height in Image

Example

See Also

dimensions width


dimensions

Returns ISize { width, height }.

Return Value

integral size of width and height

Example

See Also

height width bounds


bounds

Returns IRect { 0, 0, width, height }.

Return Value

integral rectangle from origin to width and height

Example

See Also

dimensions


uniqueID

Returns value unique to image. Image contents cannot change after Image is created. Any operation to create a new Image will receive generate a new unique number.

Return Value

unique identifier

Example

See Also

isLazyGenerated


alphaType

Returns Alpha Type, one of: kUnknown_SkAlphaType, kOpaque_SkAlphaType, kPremul_SkAlphaType, kUnpremul_SkAlphaType.

Alpha Type returned was a parameter to an Image constructor, or was parsed from encoded data.

Return Value

Alpha Type in Image

Example

See Also

SkImageInfo::alphaType


colorSpace

Returns Color Space, the range of colors, associated with Image. The reference count of Color Space is unchanged. The returned Color Space is immutable.

Color Space returned was passed to an Image constructor, or was parsed from encoded data. Color Space returned may be ignored when Image is drawn, depending on the capabilities of the Surface receiving the drawing.

Return Value

Color Space in Image, or nullptr

Example

See Also

refColorSpace makeColorSpace


refColorSpace

Returns a smart pointer to Color Space, the range of colors, associated with Image. The smart pointer tracks the number of objects sharing this SkColorSpace reference so the memory is released when the owners destruct.

The returned SkColorSpace is immutable.

Color Space returned was passed to an Image constructor, or was parsed from encoded data. Color Space returned may be ignored when Image is drawn, depending on the capabilities of the Surface receiving the drawing.

Return Value

Color Space in Image, or nullptr, wrapped in a smart pointer

Example

See Also

colorSpace makeColorSpace


isAlphaOnly

Returns true if Image pixels represent transparency only. If true, each pixel is packed in 8 bits as defined by kAlpha_8_SkColorType.

Return Value

true if pixels represent a transparency mask

Example

Example Output

alphaOnly = true

See Also

alphaType isOpaque


isOpaque

Returns true if pixels ignore their Alpha value and are treated as fully opaque.

Return Value

true if Alpha Type is kOpaque_SkAlphaType

Example

Example Output

isOpaque = false
isOpaque = true

See Also

alphaType isAlphaOnly


makeShader

Creates Shader from Image. Shader dimensions are taken from Image. Shader uses SkShader::TileMode rules to fill drawn area outside Image. localMatrix permits transforming Image before Canvas Matrix is applied.

Parameters

Return Value

Shader containing Image

Example

See Also

scalePixels


Creates Shader from Image. Shader dimensions are taken from Image. Shader uses SkShader::kClamp TileMode to fill drawn area outside Image. localMatrix permits transforming Image before Canvas Matrix is applied.

Parameters

Return Value

Shader containing Image

Example

See Also

scalePixels


Pixels

namedescription
peekPixelsreturns Pixmap if possible
readPixelscopies and converts pixels
readPixels(const SkImageInfo& dstInfo, void* dstPixels, size t dstRowBytes, int srcX, int srcY, CachingHint cachingHint = kAllow CachingHint) const
readPixels(const SkPixmap& dst, int srcX, int srcY, CachingHint cachingHint = kAllow CachingHint) const
scalePixelsscales and converts one Image to another

peekPixels

Copies Image pixel address, row bytes, and Image Info to pixmap, if address is available, and returns true. If pixel address is not available, return false and leave pixmap unchanged.

Parameters

Return Value

true if Image has direct access to pixels

Example

Example Output

------------
--xx----x---
-x--x--x----
-x--x--x----
-x--x-x-----
--xx-xx-xx--
-----x-x--x-
----x--x--x-
----x--x--x-
---x----xx--
------------

See Also

readPixels[2]


getTexture


isTextureBacked

Returns true the contents of Image was created on or uploaded to GPU memory, and is available as a GPU Texture.

Return Value

true if Image is a GPU Texture

Example

See Also

MakeFromTexture isValid


isValid

Returns true if Image can be drawn on either Raster Surface or GPU Surface. If context is nullptr, tests if Image draws on Raster Surface; otherwise, tests if Image draws on GPU Surface associated with context.

Image backed by GPU Texture may become invalid if associated GrContext is invalid. Lazy Image may be invalid and may not draw to Raster Surface or GPU Surface or both.

Parameters

Return Value

true if Image can be drawn

Example

See Also

isTextureBacked isLazyGenerated


getTextureHandle

Retrieves the back-end API handle of texture. If flushPendingGrContextIO is true, complete deferred I/O operations.

If origin in not nullptr, copies location of content drawn into Image.

Parameters

Return Value

back-end API texture handle, or nullptr

Example

Example

See Also

MakeFromTexture isTextureBacked


Enum SkImage::CachingHint

CachingHint selects whether Skia may internally cache Bitmaps generated by decoding Image, or by copying Image from GPU to CPU. The default behavior allows caching Bitmaps.

Choose kDisallow CachingHint if Image pixels are to be used only once, or if Image pixels reside in a cache outside of Skia, or to reduce memory pressure.

Choosing kAllow CachingHint does not ensure that pixels will be cached. Image pixels may not be cached if memory requirements are too large or pixels are not accessible.

Constants

See Also

readPixels[2] scalePixels

readPixels

Copies Rect of pixels from Image to dstPixels. Copy starts at offset (srcX, srcY), and does not exceed Image (width, height).

dstInfo specifies width, height, Color Type, Alpha Type, and Color Space of destination. dstRowBytes specifics the gap from one destination row to the next. Returns true if pixels are copied. Returns false if:

Pixels are copied only if pixel conversion is possible. If Image Color Type is kGray_8_SkColorType, or kAlpha_8_SkColorType; dstInfo.colorType must match. If Image Color Type is kGray_8_SkColorType, dstInfo.colorSpace must match. If Image Alpha Type is kOpaque_SkAlphaType, dstInfo.alphaType must match. If Image Color Space is nullptr, dstInfo.colorSpace must match. Returns false if pixel conversion is not possible.

srcX and srcY may be negative to copy only top or left of source. Returns false if width or height is zero or negative. Returns false ifabs(srcX) >= Image width, or ifabs(srcY) >= Image height.

If cachingHint is kAllow CachingHint, pixels may be retained locally. If cachingHint is kDisallow CachingHint, pixels are not added to the local cache.

Parameters

Return Value

true if pixels are copied to dstPixels

Example

See Also

scalePixels SkBitmap::readPixels[2][3][4] SkPixmap::readPixels[2][3][4][5] SkCanvas::readPixels[2][3] SkSurface::readPixels[2][3]


Copies a Rect of pixels from Image to dst. Copy starts at (srcX, srcY), and does not exceed Image (width, height).

dst specifies width, height, Color Type, Alpha Type, Color Space, pixel storage, and row bytes of destination. dst.rowBytes specifics the gap from one destination row to the next. Returns true if pixels are copied. Returns false if:

Pixels are copied only if pixel conversion is possible. If Image Color Type is kGray_8_SkColorType, or kAlpha_8_SkColorType; dst.colorType must match. If Image Color Type is kGray_8_SkColorType, dst.colorSpace must match. If Image Alpha Type is kOpaque_SkAlphaType, dst.alphaType must match. If Image Color Space is nullptr, dst.colorSpace must match. Returns false if pixel conversion is not possible. srcX and srcY may be negative to copy only top or left of source. Returns false if width or height is zero or negative. Returns false ifabs(srcX) >= Image width, or ifabs(srcY) >= Image height.

If cachingHint is kAllow CachingHint, pixels may be retained locally. If cachingHint is kDisallow CachingHint, pixels are not added to the local cache.

Parameters

Return Value

true if pixels are copied to dst

Example

See Also

scalePixels SkBitmap::readPixels[2][3][4] SkPixmap::readPixels[2][3][4][5] SkCanvas::readPixels[2][3] SkSurface::readPixels[2][3]


scalePixels

Copies Image to dst, scaling pixels to fit dst.width and dst.height, and converting pixels to match dst.colorType and dst.alphaType. Returns true if pixels are copied. Returns false if dst.addr() is nullptr, or dst.rowBytes is less than dst SkImageInfo::minRowBytes.

Pixels are copied only if pixel conversion is possible. If Image Color Type is kGray_8_SkColorType, or kAlpha_8_SkColorType; dst.colorType must match. If Image Color Type is kGray_8_SkColorType, dst.colorSpace must match. If Image Alpha Type is kOpaque_SkAlphaType, dst.alphaType must match. If Image Color Space is nullptr, dst.colorSpace must match. Returns false if pixel conversion is not possible.

Scales the image, with filterQuality, to match dst.width and dst.height. filterQuality kNone_SkFilterQuality is fastest, typically implemented with Filter Quality Nearest Neighbor. kLow_SkFilterQuality is typically implemented with Filter Quality Bilerp. kMedium_SkFilterQuality is typically implemented with Filter Quality Bilerp, and Filter Quality MipMap when size is reduced. kHigh_SkFilterQuality is slowest, typically implemented with Filter Quality BiCubic.

If cachingHint is kAllow CachingHint, pixels may be retained locally. If cachingHint is kDisallow CachingHint, pixels are not added to the local cache.

Parameters

Return Value

true if pixels are scaled to fit dst

Example

See Also

SkCanvas::drawImage[2] readPixels[2] SkPixmap::scalePixels


encodeToData

Encodes Image pixels, returning result as SkData.

Returns nullptr if encoding fails, or if encodedImageFormat is not supported.

Image encoding in a format requires both building with one or more of: SK_HAS_JPEG_LIBRARY, SK_HAS_PNG_LIBRARY, SK_HAS_WEBP_LIBRARY; and platform support for the encoded format.

If SK_BUILD_FOR_MAC or SK_BUILD_FOR_IOS is defined, encodedImageFormat can additionally be one of: SkEncodedImageFormat::kICO, SkEncodedImageFormat::kBMP, SkEncodedImageFormat::kGIF.

quality is a platform and format specific metric trading off size and encoding error. When used, quality equaling 100 encodes with the least error. quality may be ignored by the encoder.

Parameters

Return Value

encoded Image, or nullptr

Example

See Also

refEncodedData MakeFromEncoded


Encodes Image pixels, returning result as SkData. Returns existing encoded data if present; otherwise, Image is encoded with SkEncodedImageFormat::kPNG. Skia must be built with SK_HAS_PNG_LIBRARY to encode Image.

Returns nullptr if existing encoded data is missing or invalid, and encoding fails.

Return Value

encoded Image, or nullptr

Example

See Also

refEncodedData MakeFromEncoded


refEncodedData

Returns encoded Image pixels as SkData, if Image was created from supported encoded stream format. Platform support for formats vary and may require building with one or more of: SK_HAS_JPEG_LIBRARY, SK_HAS_PNG_LIBRARY, SK_HAS_WEBP_LIBRARY.

Returns nullptr if Image contents are not encoded.

Return Value

encoded Image, or nullptr

Example

See Also

encodeToData[2] MakeFromEncoded


Utility

namedescription
encodeToDatareturns encoded Image as SkData
encodeToData(SkEncodedImageFormat encodedImageFormat, int quality) const
encodeToData const
refEncodedDatareturns Image encoded in SkData if present
toStringconverts Image to machine readable form

toString

Appends Image description to string, including unique ID, width, height, and whether the image is opaque.

Parameters

Return Value

string appended with Image description

Example

See Also

SkPaint::toString


makeSubset

Returns subset of Image. subset must be fully contained by Image dimensions. The implementation may share pixels, or may copy them.

Returns nullptr if subset is empty, or subset is not contained by bounds, or pixels in Image could not be read or copied.

Parameters

Return Value

partial or full Image, or nullptr

Example

See Also

MakeFromEncoded


makeTextureImage

Returns Image backed by GPU Texture associated with context. Returned Image is compatible with Surface created with dstColorSpace. Returns original Image if context and dstColorSpace match.

Returns nullptr if context is nullptr, or if Image was created with another GrContext.

Parameters

Return Value

created Image, or nullptr

Example

See Also

MakeFromTexture


makeNonTextureImage

Returns Raster Image or Lazy Image. Copies Image backed by GPU Texture into CPU memory if needed. Returns original Image if decoded in Raster Bitmap, or if encoded in a stream.

Returns nullptr if backed by GPU Texture and copy fails.

Return Value

Raster Image, Lazy Image, or nullptr

Example

See Also

makeTextureImage makeRasterImage MakeBackendTextureFromSkImage


makeRasterImage

Returns Raster Image. Copies Image backed by GPU Texture into CPU memory, or decodes Image from Lazy Image. Returns original Image if decoded in Raster Bitmap.

Returns nullptr if copy, decode, or pixel read fails.

Return Value

Raster Image, or nullptr

Example

See Also

isTextureBacked isLazyGenerated MakeFromRaster


makeWithFilter

Creates filtered Image. filter processes original Image, potentially changing color, position, and size. subset is the bounds of original Image processed by filter. clipBounds is the expected bounds of the filtered Image. outSubset is required storage for the actual bounds of the filtered Image. offset is required storage for translation of returned Image.

Returns nullptr if Image could not be created. If nullptr is returned, outSubset and offset are undefined.

Useful for animation of SkImageFilter that varies size from frame to frame. Returned Image is created larger than required by filter so that GPU Texture can be reused with different sized effects. outSubset describes the valid bounds of GPU Texture returned. offset translates the returned Image to keep subsequent animation frames aligned with respect to each other.

Parameters

Return Value

filtered Image, or nullptr

Example

See Also

makeShader[2] SkPaint::setImageFilter


BackendTextureReleaseProc

MakeBackendTextureFromSkImage

Creates a GrBackendTexture from the provided SkImage. Returns true and stores result in backendTexture and backendTextureReleaseProc if texture is created; otherwise, returns false and leaves backendTexture and backendTextureReleaseProc unmodified.

Call backendTextureReleaseProc after deleting backendTexture. backendTextureReleaseProc cleans up auxiliary data related to returned backendTexture. The caller must delete returned backendTexture after use.

If Image is both texture backed and singly referenced, image is returned in backendTexture without conversion or making a copy. Image is singly referenced if its was transferred solely using std::move().

If Image is not texture backed, returns texture with Image contents.

Parameters

Return Value

true if backend texture was created

Example

See Also

MakeFromTexture makeTextureImage


Enum SkImage::LegacyBitmapMode

soon

Constants

asLegacyBitmap

Creates raster Bitmap with same pixels as Image. If legacyBitmapMode is kRO LegacyBitmapMode, returned bitmap is read-only and immutable. Returns true if Bitmap is stored in bitmap. Returns false and resets bitmap if Bitmap write did not succeed.

Parameters

Return Value

true if Bitmap was created

Example

See Also

MakeRasterData makeRasterImage makeNonTextureImage


isLazyGenerated

Returns true if Image is backed by an image-generator or other service that creates and caches its pixels or texture on-demand.

Return Value

true if Image is created as needed

Example

Example

See Also

isTextureBacked MakeNonTextureImage


makeColorSpace

Creates Image in target Color Space. Returns nullptr if Image could not be created.

Returns original Image if it is in target Color Space. Otherwise, converts pixels from Image Color Space to target Color Space. If Image colorSpace returns nullptr, Image Color Space is assumed to be sRGB.

SkTransferFunctionBehavior is to be deprecated.

Set premulBehavior to SkTransferFunctionBehavior::kRespect to convert Image pixels to a linear space, before converting to destination Color Type and Color Space.

Set premulBehavior to SkTransferFunctionBehavior::kIgnore to treat Image pixels as linear, when converting to destination Color Type and Color Space, ignoring pixel encoding.

Parameters

Return Value

created Image in target Color Space

Example

See Also

MakeFromPixture MakeFromTexture