skia2/site/user/api/SkImageInfo_Reference.md

SkImageInfo Reference

Image Info

Overview

Subtopics

name	description
Constants	enum and enum class, const values
Constructors	functions that construct ImageInfo
Member Functions	static functions and member methods
Operators	operator overloading methods

Constants

name	description
Alpha Type	encoding for pixel transparency
Color Type	encoding for pixel color components
SkDestinationSurfaceColorMode
SkYUVColorSpace

Alpha Type

Enum SkAlphaType

enum SkAlphaType {
kUnknown SkAlphaType,
kOpaque SkAlphaType,
kPremul SkAlphaType,
kUnpremul SkAlphaType,
kLastEnum_SkAlphaType = kUnpremul SkAlphaType,
};

Describes how to interpret the alpha component of a pixel.

Constants

kUnknown_SkAlphaType	0
kOpaque_SkAlphaType	1	All pixels are stored as opaque.
kPremul_SkAlphaType	2	All pixels have their alpha premultiplied in their color components. This is the natural format for the rendering target pixels.
kUnpremul_SkAlphaType	3	All pixels have their color components stored without any regard to the alpha. e.g. this is the default configuration for PNG images. kUnpremul SkAlphaType is supported only for input images. Rendering cannot generate this on output.

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Color Type

Native Color Type

Enum SkColorType

enum SkColorType {
kUnknown SkColorType,
kAlpha 8 SkColorType,
kRGB 565 SkColorType,
kARGB 4444 SkColorType,
kRGBA 8888 SkColorType,
kBGRA 8888 SkColorType,
kGray 8 SkColorType,
kRGBA F16 SkColorType,
kLastEnum_SkColorType = kRGBA F16 SkColorType,
kN32 SkColorType = kBGRA 8888 SkColorType,
kN32 SkColorType = kRGBA 8888 SkColorType,
};

Describes how to interpret the components of a pixel. kN32 SkColorType is an alias for whichever 32 bit Color ARGB format is the "" form for skia's blitters. Use this if you don't have a swizzle preference for 32 bit pixels.

Constants

kUnknown_SkColorType	0
kAlpha_8_SkColorType	1
kRGB_565_SkColorType	2
kARGB_4444_SkColorType	3
kRGBA_8888_SkColorType	4
kBGRA_8888_SkColorType	5
kGray_8_SkColorType	6
kRGBA_F16_SkColorType	7
kN32_SkColorType	4

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Enum SkYUVColorSpace

enum SkYUVColorSpace {
kJPEG SkYUVColorSpace,
kRec601 SkYUVColorSpace,
kRec709 SkYUVColorSpace,
kLastEnum_SkYUVColorSpace = kRec709 SkYUVColorSpace,
};

Describes the color space a YUV pixel.

Constants

kJPEG_SkYUVColorSpace	0	Standard JPEG color space.
kRec601_SkYUVColorSpace	1	SDTV standard Rec. 601 color space. Uses "studio swing" [16, 235] color range. See http://en.wikipedia.org/wiki/Rec._601 for details.
kRec709_SkYUVColorSpace	2	HDTV standard Rec. 709 color space. Uses "studio swing" [16, 235] color range. See http://en.wikipedia.org/wiki/Rec._709 for details.

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Enum SkDestinationSurfaceColorMode

enum class SkDestinationSurfaceColorMode {
kLegacy,
kGammaAndColorSpaceAware,
};

Constants

SkDestinationSurfaceColorMode::kLegacy	0
SkDestinationSurfaceColorMode::kGammaAndColorSpaceAware	1

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Struct SkImageInfo

Describe an image's dimensions and pixel type. Used for both src images and render-targets (surfaces).

Operators

name	description
bool operator!=(const SkImageInfo& other) const
bool operator==(const SkImageInfo& other) const

Member Functions

name	description
ByteSizeOverflowed
Make	creates Image Info from dimensions, Color Type, Alpha Type, Color Space
MakeA8	creates Image Info with kAlpha 8 SkColorType, kPremul SkAlphaType
MakeN32	creates Image Info with Native Color Type
MakeN32Premul	creates Image Info with Native Color Type, kPremul SkAlphaType
MakeS32	creates Image Info with Native Color Type, sRGB Color Space
MakeUnknown	creates Image Info with kUnknown SkColorType, kUnknown SkAlphaType
alphaType
bounds
bytesPerPixel
colorSpace
colorType
computeByteSize
computeMinByteSize
computeOffset
dimensions
flatten
gammaCloseToSRGB
height
isEmpty
isOpaque
makeAlphaType	creates Image Info with changed Alpha Type
makeColorSpace	creates Image Info with changed Color Space
makeColorType	creates Image Info with changed Color Type
makeWH	creates Image Info with changed dimensions
minRowBytes
minRowBytes64
refColorSpace
reset
shiftPerPixel
unflatten
validRowBytes
validate
width

Constructors

name	description
Make	creates Image Info from dimensions, Color Type, Alpha Type, Color Space
MakeA8	creates Image Info with kAlpha 8 SkColorType, kPremul SkAlphaType
MakeN32	creates Image Info with Native Color Type
MakeN32Premul	creates Image Info with Native Color Type, kPremul SkAlphaType
MakeS32	creates Image Info with Native Color Type, sRGB Color Space
MakeUnknown	creates Image Info with kUnknown SkColorType, kUnknown SkAlphaType
SkImageInfo()	creates with zero dimensions, kUnknown SkColorType, kUnknown SkAlphaType
makeAlphaType	creates Image Info with changed Alpha Type
makeColorSpace	creates Image Info with changed Color Space
makeColorType	creates Image Info with changed Color Type
makeWH	creates Image Info with changed dimensions

SkImageInfo

SkImageInfo()

Return Value

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Make

static SkImageInfo Make(int width, int height, SkColorType ct, SkAlphaType at,
                        sk_sp<SkColorSpace> cs = nullptr)

Parameters

width	incomplete
height	incomplete
ct	incomplete
at	incomplete
cs	incomplete

Return Value

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MakeN32

static SkImageInfo MakeN32(int width, int height, SkAlphaType at, sk_sp<SkColorSpace> cs = nullptr)

Sets colortype to kN32 SkColorType.

Parameters

width	incomplete
height	incomplete
at	incomplete
cs	incomplete

Return Value

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MakeS32

static SkImageInfo MakeS32(int width, int height, SkAlphaType at)

Creates Image Info marked as sRGB with kN32 SkColorType swizzle.

Parameters

width	incomplete
height	incomplete
at	incomplete

Return Value

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MakeN32Premul

static SkImageInfo MakeN32Premul(int width, int height, sk_sp<SkColorSpace> cs = nullptr)

Sets colortype to kN32 SkColorType, and the alphatype to premul.

Parameters

width	incomplete
height	incomplete
cs	incomplete

Return Value

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static SkImageInfo MakeN32Premul(const SkISize& size)

Parameters

size	incomplete

Return Value

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MakeA8

static SkImageInfo MakeA8(int width, int height)

Parameters

width	incomplete
height	incomplete

Return Value

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MakeUnknown

static SkImageInfo MakeUnknown(int width, int height)

Parameters

width	incomplete
height	incomplete

Return Value

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static SkImageInfo MakeUnknown()

Return Value

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width

int width() const

Return Value

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height

int height() const

Return Value

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colorType

SkColorType colorType() const

Return Value

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alphaType

SkAlphaType alphaType() const

Return Value

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colorSpace

SkColorSpace* colorSpace() const

Return Value

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refColorSpace

sk_sp<SkColorSpace> refColorSpace() const

Return Value

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isEmpty

bool isEmpty() const

Return Value

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isOpaque

bool isOpaque() const

Return Value

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dimensions

SkISize dimensions() const

Return Value

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bounds

SkIRect bounds() const

Return Value

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gammaCloseToSRGB

bool gammaCloseToSRGB() const

Return Value

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makeWH

SkImageInfo makeWH(int newWidth, int newHeight) const

Creates Image Info with the same colortype and alphatype as this info, but with the specified width and height.

Parameters

newWidth	incomplete
newHeight	incomplete

Return Value

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makeAlphaType

SkImageInfo makeAlphaType(SkAlphaType newAlphaType) const

Parameters

newAlphaType

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Return Value

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makeColorType

SkImageInfo makeColorType(SkColorType newColorType) const

Parameters

newColorType

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Return Value

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makeColorSpace

SkImageInfo makeColorSpace(sk_sp<SkColorSpace> cs) const

Parameters

cs	incomplete

Return Value

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bytesPerPixel

int bytesPerPixel() const

Return Value

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shiftPerPixel

int shiftPerPixel() const

Return Value

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minRowBytes64

uint64_t minRowBytes64() const

Return Value

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minRowBytes

size_t minRowBytes() const

Return Value

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computeOffset

size_t computeOffset(int x, int y, size_t rowBytes) const

Parameters

x	incomplete
y	incomplete
rowBytes	incomplete

Return Value

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operator==

bool operator==(const SkImageInfo& other) _const

Parameters

other

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Return Value

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operator!=

bool operator!=(const SkImageInfo& other) _const

Parameters

other

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Return Value

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unflatten

void unflatten(SkReadBuffer& buffer)

Parameters

buffer

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flatten

void flatten(SkWriteBuffer& buffer) const

Parameters

buffer

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computeByteSize

size_t computeByteSize(size_t rowBytes) const

Returns the size (in bytes) of the image buffer that this info needs, given the specified rowBytes. The rowBytes must be >= this->minRowBytes. if (height == 0) { return 0; } else { return (height - 1) * rowBytes + width * bytes_per_pixel.

If the calculation overflows this returns SK MaxSizeT.

Parameters

rowBytes

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Return Value

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computeMinByteSize

size_t computeMinByteSize() const

Returns the minimum size (in bytes) of the image buffer that this info needs. If the calculation overflows, or if the height is 0, this returns 0.

Return Value

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ByteSizeOverflowed

static bool ByteSizeOverflowed(size_t byteSize)

Returns true if the result of computeByteSize (or computeMinByteSize) overflowed

Parameters

byteSize

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Return Value

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validRowBytes

bool validRowBytes(size_t rowBytes) const

Parameters

rowBytes

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Return Value

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reset

void reset()

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validate

void validate() const

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