SkImage Reference

Image

Class SkImage

Constant

SkImage related constants are defined by enum, enum class, #define, const, and constexpr.

Topic Description
BitDepth::kF16 uses 16-bit float per Color component
BitDepth::kU8 uses 8-bit unsigned int per Color component
BitDepth options for MakeFromPicture
CachingHint options for readPixels and scalePixels
kAllow CachingHint allows internally caching decoded and copied pixels
kDisallow CachingHint disallows internally caching decoded and copied pixels
kRO LegacyBitmapMode returned bitmap is read-only and immutable

Typedef

SkImage typedef define a data type.

Topic Description
BackendTextureReleaseProc parameter type for MakeBackendTextureFromSkImage
RasterReleaseProc parameter type for MakeFromRaster
ReleaseContext parameter type for MakeFromRaster
TextureReleaseProc parameter type for MakeFromTexture

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.

Overview

Topic Description
Constants enum and enum class, and their const values
Constructors functions that construct SkImage
Functions global and class member functions
Related Functions similar member functions grouped together
Typedef Declarations types defined by other types

Related Function

SkImage global, struct, and class related member functions share a topic.

Topic Description
Lazy Image deferred pixel buffer
Pixels read and write pixel values
Property values and attributes
Raster Image pixels decoded in Raster Bitmap
Texture Image pixels located on GPU
Utility rarely called management functions

Constructor

SkImage can be constructed or initialized by these functions, including C++ class constructors.

Topic Description
MakeBackendTextureFromSkImage creates GPU Texture from Image
MakeCrossContextFromEncoded creates Image from encoded data, and uploads to GPU
MakeCrossContextFromPixmap creates Image from Pixmap, and uploads to GPU
MakeFromAHardwareBuffer creates Image from Android hardware buffer
MakeFromAdoptedTexture creates Image from GPU Texture, managed internally
MakeFromBitmap creates Image from Bitmap, sharing or copying pixels
MakeFromEncoded creates Image from encoded data
MakeFromGenerator creates Image from a stream of data
MakeFromNV12TexturesCopy creates Image from YUV ColorSpace data in three planes
MakeFromPicture creates Image from Picture
MakeFromRaster creates Image from Pixmap, with release
MakeFromTexture creates Image from GPU Texture
MakeFromTexture(GrContext* context, const GrBackendTexture& backendTexture, GrSurfaceOrigin origin, SkColorType colorType, SkAlphaType alphaType, sk sp<SkColorSpace> colorSpace)
MakeFromTexture(GrContext* context, const GrBackendTexture& backendTexture, GrSurfaceOrigin origin, SkColorType colorType, SkAlphaType alphaType, sk sp<SkColorSpace> colorSpace, TextureReleaseProc textureReleaseProc, ReleaseContext releaseContext)
MakeFromYUVTexturesCopy creates Image from YUV ColorSpace data in three planes
MakeRasterCopy creates Image from Pixmap and copied pixels
MakeRasterData creates Image from Image Info and shared pixels
asLegacyBitmap returns as Raster Bitmap
makeColorSpace creates Image matching Color Space if possible
makeNonTextureImage creates Image without dependency on GPU Texture
makeRasterImage creates Image compatible with Raster Surface if possible
makeShader creates 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
makeSubset creates Image containing part of original
makeTextureImage creates Image matching Color Space if possible
makeWithFilter creates filtered, clipped Image

Member Function

SkImage member functions read and modify the structure properties.

Topic Description
MakeBackendTextureFromSkImage creates GPU Texture from Image
MakeCrossContextFromEncoded creates Image from encoded data, and uploads to GPU
MakeCrossContextFromPixmap creates Image from Pixmap, and uploads to GPU
MakeFromAHardwareBuffer creates Image from Android hardware buffer
MakeFromAdoptedTexture creates Image from GPU Texture, managed internally
MakeFromBitmap creates Image from Bitmap, sharing or copying pixels
MakeFromEncoded creates Image from encoded data
MakeFromGenerator creates Image from a stream of data
MakeFromNV12TexturesCopy creates Image from YUV ColorSpace data in three planes
MakeFromPicture creates Image from Picture
MakeFromRaster creates Image from Pixmap, with release
MakeFromTexture creates Image from GPU Texture
MakeFromYUVTexturesCopy creates Image from YUV ColorSpace data in three planes
MakeRasterCopy creates Image from Pixmap and copied pixels
MakeRasterData creates Image from Image Info and shared pixels
alphaType returns Alpha Type
asLegacyBitmap returns as Raster Bitmap
bounds returns width and height as Rectangle
colorSpace returns Color Space
colorType returns Color Type
dimensions returns width and height
encodeToData returns encoded Image as SkData
getBackendTexture returns GPU reference to Image as texture
height returns pixel row count
isAlphaOnly returns if pixels represent a transparency mask
isLazyGenerated returns if Image is created as needed
isOpaque returns if Alpha Type is kOpaque_SkAlphaType
isTextureBacked returns if Image was created from GPU Texture
isValid returns if Image can draw to Raster Surface or GPU Context
makeColorSpace creates Image matching Color Space if possible
makeNonTextureImage creates Image without dependency on GPU Texture
makeRasterImage creates Image compatible with Raster Surface if possible
makeShader creates Shader, Paint element that can tile Image
makeSubset creates Image containing part of original
makeTextureImage creates Image matching Color Space if possible
makeWithFilter creates filtered, clipped Image
peekPixels returns Pixmap if possible
readPixels copies and converts pixels
refColorSpace returns Image Info Color Space
refEncodedData returns Image encoded in SkData if present
scalePixels scales and converts one Image to another
uniqueID returns identifier for Image
width returns pixel column count

MakeRasterCopy

static sk sp<SkImage> MakeRasterCopy(const SkPixmap& pixmap)

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

pixmap Image Info, pixel address, and row bytes

Return Value

copy of Pixmap pixels, or nullptr

Example

Draw a five by five bitmap, and draw a copy in an Image. Editing the pixmap alters the bitmap draw, but does not alter the Image draw since the Image contains a copy of the pixels.

See Also

MakeRasterData MakeFromGenerator


MakeRasterData

static sk sp<SkImage> MakeRasterData(const SkImageInfo& info, sk sp<SkData> pixels, size_t rowBytes)

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

info contains width, height, Alpha Type, Color Type, Color Space
pixels address or pixel storage
rowBytes size of pixel row or larger

Return Value

Image sharing pixels, or nullptr

Example

See Also

MakeRasterCopy MakeFromGenerator


Typedef SkImage::ReleaseContext

typedef void* ReleaseContext;

Caller data passed to RasterReleaseProc; may be nullptr.

See Also

MakeFromRaster RasterReleaseProc

Typedef SkImage::RasterReleaseProc

typedef void (*RasterReleaseProc)(const void* pixels, ReleaseContext);

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

static sk sp<SkImage> MakeFromRaster(const SkPixmap& pixmap, RasterReleaseProc rasterReleaseProc,
                                     ReleaseContext releaseContext)

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

pixmap Image Info, pixel address, and row bytes
rasterReleaseProc function called when pixels can be released; or nullptr
releaseContext state passed to rasterReleaseProc; or nullptr

Return Value

Image sharing pixmap

Example

#### Example Output ~~~~ before reset: 0 after reset: 1 ~~~~

See Also

MakeRasterCopy MakeRasterData MakeFromGenerator RasterReleaseProc ReleaseContext


MakeFromBitmap

static sk sp<SkImage> MakeFromBitmap(const SkBitmap& bitmap)

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

bitmap Image Info, row bytes, and pixels

Return Value

created Image, or nullptr

Example

The first Bitmap is shared; writing to the pixel memory changes the first Image. The second Bitmap is marked immutable, and is copied; writing to the pixel memory does not alter the second Image.

See Also

MakeFromRaster MakeRasterCopy MakeFromGenerator MakeRasterData


MakeFromGenerator

static sk sp<SkImage> MakeFromGenerator(std::unique_ptr<SkImageGenerator> imageGenerator,
                                 const SkIRect* subset = nullptr)

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

imageGenerator stock or custom routines to retrieve Image
subset bounds of returned Image; may be nullptr

Return Value

created Image, or nullptr

Example

The generator returning Picture cannot be shared; std::move transfers ownership to generated Image.

See Also

MakeFromEncoded


MakeFromEncoded

static sk sp<SkImage> MakeFromEncoded(sk sp<SkData> encoded, const SkIRect* subset = nullptr)

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

encoded data of Image to decode
subset bounds of returned Image; may be nullptr

Return Value

created Image, or nullptr

Example

See Also

MakeFromGenerator


Typedef SkImage::TextureReleaseProc

typedef void (*TextureReleaseProc)(ReleaseContext releaseContext);

User function called when supplied texture may be deleted.

See Also

MakeFromTexture[2]

MakeFromTexture

static sk sp<SkImage> MakeFromTexture(GrContext* context, const GrBackendTexture& backendTexture,
                                      GrSurfaceOrigin origin, SkColorType colorType,
                                      SkAlphaType alphaType, sk sp<SkColorSpace> colorSpace)

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

context GPU Context
backendTexture texture residing on GPU
origin one of: kBottomLeft GrSurfaceOrigin, kTopLeft GrSurfaceOrigin
colorType one of: 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
alphaType one of: kUnknown_SkAlphaType, kOpaque_SkAlphaType, kPremul_SkAlphaType, kUnpremul_SkAlphaType
colorSpace range of colors; may be nullptr

Return Value

created Image, or nullptr

Example

A back-end texture has been created and uploaded to the GPU outside of this example.

See Also

MakeFromAdoptedTexture SkSurface::MakeFromBackendTexture


static sk sp<SkImage> MakeFromTexture(GrContext* context, const GrBackendTexture& backendTexture,
                                      GrSurfaceOrigin origin, SkColorType colorType,
                                      SkAlphaType alphaType, sk sp<SkColorSpace> colorSpace,
                                      TextureReleaseProc textureReleaseProc,
                                      ReleaseContext releaseContext)

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

context GPU Context
backendTexture texture residing on GPU
origin one of: kBottomLeft GrSurfaceOrigin, kTopLeft GrSurfaceOrigin
colorType one of: 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
alphaType one of: kUnknown_SkAlphaType, kOpaque_SkAlphaType, kPremul_SkAlphaType, kUnpremul_SkAlphaType
colorSpace range of colors; may be nullptr
textureReleaseProc function called when texture can be released
releaseContext state passed to textureReleaseProc

Return Value

created Image, or nullptr

Example

See Also

MakeFromAdoptedTexture SkSurface::MakeFromBackendTexture


MakeCrossContextFromEncoded

static sk sp<SkImage> MakeCrossContextFromEncoded(GrContext* context, sk sp<SkData> data,
                                                  bool buildMips, SkColorSpace* dstColorSpace,
                                                  bool limitToMaxTextureSize = false)

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

context GPU Context
data Image to decode
buildMips create Image as Mip Map if true
dstColorSpace range of colors of matching Surface on GPU
limitToMaxTextureSize downscale image to GPU maximum texture size, if necessary

Return Value

created Image, or nullptr

Example

See Also

MakeCrossContextFromPixmap


MakeCrossContextFromPixmap

static sk sp<SkImage> MakeCrossContextFromPixmap(GrContext* context, const SkPixmap& pixmap,
                                                 bool buildMips, SkColorSpace* dstColorSpace,
                                                 bool limitToMaxTextureSize = false)

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

context GPU Context
pixmap Image Info, pixel address, and row bytes
buildMips create Image as Mip Map if true
dstColorSpace range of colors of matching Surface on GPU
limitToMaxTextureSize downscale image to GPU maximum texture size, if necessary

Return Value

created Image, or nullptr

Example

See Also

MakeCrossContextFromEncoded


MakeFromAdoptedTexture

static sk sp<SkImage> MakeFromAdoptedTexture(GrContext* context,
                                             const GrBackendTexture& backendTexture,
                                             GrSurfaceOrigin surfaceOrigin, SkColorType colorType,
                                             SkAlphaType alphaType = kPremul_SkAlphaType,
                                             sk sp<SkColorSpace> colorSpace = nullptr)

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

context GPU Context
backendTexture texture residing on GPU
surfaceOrigin one of: kBottomLeft GrSurfaceOrigin, kTopLeft GrSurfaceOrigin
colorType one of: 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
alphaType one of: kUnknown_SkAlphaType, kOpaque_SkAlphaType, kPremul_SkAlphaType, kUnpremul_SkAlphaType
colorSpace range of colors; may be nullptr

Return Value

created Image, or nullptr

Example

See Also

MakeFromTexture[2] MakeFromYUVTexturesCopy


MakeFromYUVTexturesCopy

static sk sp<SkImage> MakeFromYUVTexturesCopy(GrContext* context, SkYUVColorSpace yuvColorSpace,
                                              const GrBackendTexture yuvTextures[3],
                                              GrSurfaceOrigin surfaceOrigin,
                                              sk sp<SkColorSpace> colorSpace = nullptr)

Creates Image from copy of yuvTextures, an array of textures on GPU. yuvTextures contain pixels for YUV planes of Image. Returned Image has the dimensions yuvTextures[0]. yuvColorSpace describes how YUV colors convert to RGB colors.

Parameters

context GPU Context
yuvColorSpace one of: kJPEG_SkYUVColorSpace, kRec601_SkYUVColorSpace, kRec709_SkYUVColorSpace
yuvTextures array of YUV textures on GPU
surfaceOrigin one of: kBottomLeft GrSurfaceOrigin, kTopLeft GrSurfaceOrigin
colorSpace range of colors; may be nullptr

Return Value

created Image, or nullptr

See Also

MakeFromNV12TexturesCopy


MakeFromNV12TexturesCopy

static sk sp<SkImage> MakeFromNV12TexturesCopy(GrContext* context, SkYUVColorSpace yuvColorSpace,
                                               const GrBackendTexture nv12Textures[2],
                                               GrSurfaceOrigin surfaceOrigin,
                                               sk sp<SkColorSpace> colorSpace = nullptr)

Creates Image from copy of nv12Textures, an array of textures on GPU. nv12Textures[0] contains pixels for YUV Component Y plane. nv12Textures[1] contains pixels for YUV Component U plane, followed by pixels for YUV Component V plane. Returned Image has the dimensions nv12Textures[2]. yuvColorSpace describes how YUV colors convert to RGB colors.

Parameters

context GPU Context
yuvColorSpace one of: kJPEG_SkYUVColorSpace, kRec601_SkYUVColorSpace, kRec709_SkYUVColorSpace
nv12Textures array of YUV textures on GPU
surfaceOrigin one of: kBottomLeft GrSurfaceOrigin, kTopLeft GrSurfaceOrigin
colorSpace range of colors; may be nullptr

Return Value

created Image, or nullptr

See Also

MakeFromYUVTexturesCopy


Enum SkImage::BitDepth

    enum class BitDepth {
        kU8,
        kF16,
    };

Constants

Const Value Description
SkImage::BitDepth::kU8 0 Use 8 bits per ARGB component using unsigned integer format.
SkImage::BitDepth::kF16 1 Use 16 bits per ARGB component using half-precision floating point format.

See Also

MakeFromPicture

MakeFromPicture

static sk sp<SkImage> MakeFromPicture(sk sp<SkPicture> picture, const SkISize& dimensions,
                                      const SkMatrix* matrix, const SkPaint* paint,
                                      BitDepth bitDepth, sk sp<SkColorSpace> colorSpace)

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

picture stream of drawing commands
dimensions width and height
matrix Matrix to rotate, scale, translate, and so on; may be nullptr
paint Paint to apply transparency, filtering, and so on; may be nullptr
bitDepth 8-bit integer or 16-bit float: per component
colorSpace range of colors; may be nullptr

Return Value

created Image, or nullptr

Example

See Also

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


MakeFromAHardwareBuffer

static sk sp<SkImage> MakeFromAHardwareBuffer(AHardwareBuffer* hardwareBuffer,
                                            SkAlphaType alphaType = kPremul_SkAlphaType,
                                            sk sp<SkColorSpace> colorSpace = nullptr)

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

hardwareBuffer AHardwareBuffer Android hardware buffer
alphaType one of: kUnknown_SkAlphaType, kOpaque_SkAlphaType, kPremul_SkAlphaType, kUnpremul_SkAlphaType
colorSpace range of colors; may be nullptr

Return Value

created Image, or nullptr

See Also

MakeFromRaster


Property

Topic Description
alphaType returns Alpha Type
bounds returns width and height as Rectangle
colorSpace returns Color Space
colorType returns Color Type
dimensions returns width and height
getBackendTexture returns GPU reference to Image as texture
height returns pixel row count
isAlphaOnly returns if pixels represent a transparency mask
isLazyGenerated returns if Image is created as needed
isOpaque returns if Alpha Type is kOpaque_SkAlphaType
isTextureBacked returns if Image was created from GPU Texture
isValid returns if Image can draw to Raster Surface or GPU Context
refColorSpace returns Image Info Color Space
uniqueID returns identifier for Image
width returns pixel column count

width

int width() const

Returns pixel count in each row.

Return Value

pixel width in Image

Example

See Also

dimensions height


height

int height() const

Returns pixel row count.

Return Value

pixel height in Image

Example

See Also

dimensions width


dimensions

SkISize dimensions() const

Returns ISize { width, height }.

Return Value

integral size of width and height

Example

#### Example Output ~~~~ dimensionsAsBounds == bounds ~~~~

See Also

height width bounds


bounds

SkIRect bounds() const

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

Return Value

integral rectangle from origin to width and height

Example

See Also

dimensions


uniqueID

uint32_t uniqueID() const

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

SkAlphaType alphaType() const

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


colorType

SkColorType colorType() const

Returns Color Type if known; otherwise, returns kUnknown_SkColorType.

Return Value

Color Type of Image

Example

See Also

SkImageInfo::colorType


colorSpace

SkColorSpace* colorSpace() const

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

sk sp<SkColorSpace> refColorSpace() const

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

bool isAlphaOnly() const

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

bool isOpaque() const

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

sk sp<SkShader> makeShader(SkShader::TileMode tileMode1, SkShader::TileMode tileMode2,
                           const SkMatrix* localMatrix = nullptr) const

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

tileMode1 tiling on x-axis, one of: SkShader::kClamp TileMode, SkShader::kRepeat TileMode, SkShader::kMirror TileMode
tileMode2 tiling on y-axis, one of: SkShader::kClamp TileMode, SkShader::kRepeat TileMode, SkShader::kMirror TileMode
localMatrix Image transformation, or nullptr

Return Value

Shader containing Image

Example

See Also

scalePixels


sk sp<SkShader> makeShader(const SkMatrix* localMatrix = nullptr) const

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

localMatrix Image transformation, or nullptr

Return Value

Shader containing Image

Example

See Also

scalePixels


Pixels

Topic Description
peekPixels returns Pixmap if possible
readPixels copies 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
scalePixels scales and converts one Image to another

peekPixels

bool peekPixels(SkPixmap* pixmap) const

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

pixmap storage for pixel state if pixels are readable; otherwise, ignored

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

GrTexture* getTexture() const

Deprecated.


isTextureBacked

bool isTextureBacked() const

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[2] isValid


isValid

bool isValid(GrContext* context) const

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

context GPU Context

Return Value

true if Image can be drawn

Example

See Also

isTextureBacked isLazyGenerated


getBackendTexture

GrBackendTexture getBackendTexture(bool flushPendingGrContextIO, GrSurfaceOrigin* origin = nullptr) const

Retrieves the back-end texture. If Image has no back-end texture, an invalid object is returned. Call GrBackendTexture::isValid to determine if the result is valid.

If flushPendingGrContextIO is true, completes deferred I/O operations.

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

Parameters

flushPendingGrContextIO flag to flush outstanding requests
origin storage for one of: kTopLeft GrSurfaceOrigin, kBottomLeft GrSurfaceOrigin; or nullptr

Return Value

back-end API texture handle; invalid on failure

Example

See Also

MakeFromTexture[2] isTextureBacked


Enum SkImage::CachingHint

    enum CachingHint {
        kAllow CachingHint,
        kDisallow 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

Const Value Description
SkImage::kAllow_CachingHint 0 allows internally caching decoded and copied pixels
SkImage::kDisallow_CachingHint 1 disallows internally caching decoded and copied pixels

See Also

readPixels[2] scalePixels

readPixels

bool readPixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dstRowBytes, int srcX, int srcY,
                CachingHint cachingHint = kAllow CachingHint) const

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:

dstInfo.addr() equals nullptr
dstRowBytes is less than dstInfo.minRowBytes
Pixel Ref is nullptr

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

dstInfo destination width, height, Color Type, Alpha Type, Color Space
dstPixels destination pixel storage
dstRowBytes destination row length
srcX column index whose absolute value is less than width
srcY row index whose absolute value is less than height
cachingHint one of: kAllow CachingHint, kDisallow CachingHint

Return Value

true if pixels are copied to dstPixels

Example

See Also

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


bool readPixels(const SkPixmap& dst, int srcX, int srcY, CachingHint cachingHint = kAllow CachingHint) const

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:

dst pixel storage equals nullptr
dst.rowBytes is less than SkImageInfo::minRowBytes
Pixel Ref is nullptr

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

dst destination Pixmap: Image Info, pixels, row bytes
srcX column index whose absolute value is less than width
srcY row index whose absolute value is less than height
cachingHint one of: kAllow CachingHint, kDisallow CachingHint

Return Value

true if pixels are copied to dst

Example

See Also

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


scalePixels

bool scalePixels(const SkPixmap& dst, SkFilterQuality filterQuality,
                 CachingHint cachingHint = kAllow CachingHint) const

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

dst destination Pixmap: Image Info, pixels, row bytes
filterQuality one of: kNone_SkFilterQuality, kLow_SkFilterQuality, kMedium_SkFilterQuality, kHigh_SkFilterQuality
cachingHint one of: kAllow CachingHint, kDisallow CachingHint

Return Value

true if pixels are scaled to fit dst

Example

See Also

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


encodeToData

sk sp<SkData> encodeToData(SkEncodedImageFormat encodedImageFormat, int quality) const

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

encodedImageFormat one of: SkEncodedImageFormat::kJPEG, SkEncodedImageFormat::kPNG, SkEncodedImageFormat::kWEBP
quality encoder specific metric with 100 equaling best

Return Value

encoded Image, or nullptr

Example

See Also

refEncodedData MakeFromEncoded


sk sp<SkData> encodeToData() const

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

sk sp<SkData> refEncodedData() const

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

Topic Description
encodeToData returns encoded Image as SkData
encodeToData(SkEncodedImageFormat encodedImageFormat, int quality) const
encodeToData const
refEncodedData returns Image encoded in SkData if present

makeSubset

sk sp<SkImage> makeSubset(const SkIRect& subset) const

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

subset bounds of returned Image

Return Value

partial or full Image, or nullptr

Example

See Also

MakeFromEncoded


makeTextureImage

sk sp<SkImage> makeTextureImage(GrContext* context, SkColorSpace* dstColorSpace,
                                GrMipMapped mipMapped = GrMipMapped::kNo) const

Returns Image backed by GPU Texture associated with context. Returned Image is compatible with Surface created with dstColorSpace. The returned Image respects mipMapped setting; if mipMapped equals GrMipMapped::kYes, the backing texture allocates Mip Map levels. Returns original Image if context and dstColorSpace match and mipMapped is compatible with backing GPU Texture.

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

Parameters

context GPU Context
dstColorSpace range of colors of matching Surface on GPU
mipMapped whether created Image texture must allocate Mip Map levels

Return Value

created Image, or nullptr

Example

See Also

MakeFromTexture[2]


makeNonTextureImage

sk sp<SkImage> makeNonTextureImage() const

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

sk sp<SkImage> makeRasterImage() const

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

sk sp<SkImage> makeWithFilter(const SkImageFilter* filter, const SkIRect& subset,
                              const SkIRect& clipBounds, SkIRect* outSubset, SkIPoint* offset) const

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

filter how Image is sampled when transformed
subset bounds of Image processed by filter
clipBounds expected bounds of filtered Image
outSubset storage for returned Image bounds
offset storage for returned Image translation

Return Value

filtered Image, or nullptr

Example

In each frame of the animation, filtered Image is drawn in a different location. By translating canvas by returned offset, Image appears stationary.

See Also

makeShader[2] SkPaint::setImageFilter


Typedef SkImage::BackendTextureReleaseProc

BackendTextureReleaseProc

typedef std::function BackendTextureReleaseProc;

Defines a callback function, taking one parameter of type GrBackendTexture with no return value. Function is called when back-end texture is to be released.

MakeBackendTextureFromSkImage

static bool MakeBackendTextureFromSkImage(GrContext* context, sk sp<SkImage> image,
                                          GrBackendTexture* backendTexture,
                                          BackendTextureReleaseProc* backendTextureReleaseProc)

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

context GPU Context
image Image used for texture
backendTexture storage for back-end texture
backendTextureReleaseProc storage for clean up function

Return Value

true if back-end texture was created

Example

See Also

MakeFromTexture[2] makeTextureImage


Enum SkImage::LegacyBitmapMode

Deprecated.

soon

    enum LegacyBitmapMode {
        kRO LegacyBitmapMode,
    };

Constants

Const Value Description
SkImage::kRO_LegacyBitmapMode 0 returned bitmap is read-only and immutable

asLegacyBitmap

bool asLegacyBitmap(SkBitmap* bitmap, LegacyBitmapMode legacyBitmapMode = kRO LegacyBitmapMode) const

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

bitmap storage for legacy Bitmap
legacyBitmapMode to be deprecated

Return Value

true if Bitmap was created

Example

See Also

MakeRasterData makeRasterImage makeNonTextureImage


isLazyGenerated

bool isLazyGenerated() const

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

sk sp<SkImage> makeColorSpace(sk sp<SkColorSpace> target) const

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.

Parameters

target Color Space describing color range of returned Image

Return Value

created Image in target Color Space

Example

See Also

MakeFromPixture MakeFromTexture[2]