SkImageInfo Reference === # Image Info Image Info specifies the dimensions and encoding of the pixels in a Bitmap. The dimensions are integral width and height. The encoding is how pixel bits describe Color Alpha, transparency; Color components red, blue, and green; and Color Space, the range and linearity of colors. Image Info describes an uncompressed raster pixels. In contrast, Image additionally describes compressed pixels like PNG, and Surface describes destinations on the GPU. Image and Surface may be specified by Image Info, but Image and Surface may not contain Image Info. ## Overview ## Overview Subtopic | name | description | | --- | --- | | Constructor | functions that construct SkImageInfo | | Member Function | static functions and member methods | | Operator | operator overloading methods | | Related Function | similar methods grouped together | ## Constant | name | description | | --- | --- | ## 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. A pixel may be opaque, or Color Alpha, describing multiple levels of transparency. In simple blending, Color Alpha weights the draw color and the destination color to create a new color. If alpha describes a weight from zero to one: new color = draw color * alpha + destination color * (1 - alpha)In practice alpha is encoded in two or more bits, where 1.0 equals all bits set. Color RGB may have Color Alpha included in each component value; the stored value is the original Color RGB multiplied by Color Alpha. Premultiplied color components improve performance. ### Constants

`kUnknown_SkAlphaType`	0	Alpha Type is uninitialized.
`kOpaque_SkAlphaType`	1	Pixels are opaque. The Color Type must have no explicit alpha component, or all alpha components must be set to their maximum value.
`kPremul_SkAlphaType`	2	Pixels have alpha premultiplied into color components. Surface pixels must be premultiplied.
`kUnpremul_SkAlphaType`	3	Pixel color component values are independent of alpha value. Images generated from encoded data like PNG do not premultiply pixel color components. kUnpremul_SkAlphaType is supported for Image pixels, but not for Surface pixels.

### See Also SkColorType SkColorSpace ## Alpha Type Opaque Use Opaque as a hint to optimize drawing when alpha component of all pixel is set to its maximum value of 1.0; all alpha component bits are set. If Image Info is set to Opaque but all alpha values are not 1.0, results are undefined. ### Example

SkPreMultiplyARGB parameter a is set to 255, its maximum value, and is interpreted as Color Alpha of 1.0. kOpaque_SkAlphaType may be set to improve performance. If SkPreMultiplyARGB parameter a is set to a value smaller than 255, kPremul_SkAlphaType must be used instead to avoid undefined results. The four displayed values are the original component values, though not necessarily in the same order.

## Alpha Type Premul Use Premul when stored color components are the original color multiplied by the alpha component. The alpha component range of 0.0 to 1.0 is achieved by dividing the integer bit value by the maximum bit value. stored color = original color * alpha / max alphaThe color component must be equal to or smaller than the alpha component, or the results are undefined. ### Example

SkPreMultiplyARGB parameter a is set to 150, less than its maximum value, and is interpreted as Color Alpha of about 0.6. kPremul_SkAlphaType must be set, since SkPreMultiplyARGB parameter a is set to a value smaller than 255, to avoid undefined results. The four displayed values reflect that the alpha component has been multiplied by the original color.

## Alpha Type Unpremul Use Unpremul if stored color components are not divided by the alpha component. Some drawing destinations may not support Unpremul. ### Example

SkColorSetARGB parameter a is set to 150, less than its maximum value, and is interpreted as Color Alpha of about 0.6. color is not premultiplied; color components may have values greater than color alpha. The four displayed values are the original component values, though not necessarily in the same order.

## Color Type ## Color Type Native ## Enum SkColorType

enum SkColorType {
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,
kLastEnum_SkColorType = kRGBA_F16_SkColorType,
kN32_SkColorType = kBGRA_8888_SkColorType,
kN32_SkColorType = kRGBA_8888_SkColorType,
};

Describes how pixel bits encode color. A pixel may be an alpha mask, a gray level, Color RGB, or Color ARGB. kN32_SkColorType selects the native 32-bit Color ARGB format. On Little_Endian processors, pixels containing 8-bit Color ARGB components pack into 32-bit kBGRA_8888_SkColorType. On Big_Endian processors, pixels pack into 32-bit kRGBA_8888_SkColorType. ### Constants

`kUnknown_SkColorType`	0
`kAlpha_8_SkColorType`	1	Encodes Color Alpha as Alpha 8 pixel in an 8-bit byte.
`kRGB_565_SkColorType`	2	Encodes Color RGB as BGR 565 pixel in a 16-bit word.
`kARGB_4444_SkColorType`	3	Encodes Color ARGB as ABGR 4444 pixel in a 16-bit word.
`kRGBA_8888_SkColorType`	4	Encodes Color ARGB as RGBA 8888 pixel in a 32-bit word.
`kRGB_888x_SkColorType`	5	Encodes Color RGB as RGB 888x pixel in a 32-bit word.
`kBGRA_8888_SkColorType`	6	Encodes Color ARGB as BGRA 8888 pixel in a 32-bit word.
`kRGBA_1010102_SkColorType`	7	Encodes Color ARGB as RGBA 1010102 pixel in a 32-bit word.
`kRGB_101010x_SkColorType`	8	Encodes Color RGB as RGB 101010x pixel in a 32-bit word.
`kGray_8_SkColorType`	9	Encodes Color Gray as Gray 8 in an 8-bit byte.
`kRGBA_F16_SkColorType`	10	Encodes Color ARGB as RGBA F16 in a 64-bit word.

### Constants

kN32_SkColorType 4 Encodes Color ARGB as either RGBA 8888 or BGRA 8888, whichever is native to the platform.

### See Also SkAlphaType SkColorSpace ## Color Type Alpha 8 Alpha 8 is an 8-bit byte pixel encoding that represents transparency. A value of zero is completely transparent; a value of 255 is completely opaque. Bitmap with Alpha 8 pixels does not visibly draw, because its pixels have no color information. The paired SkAlphaType is ignored. ### Example

Alpha 8 pixels can modify another draw. orangePaint fills the bounds of bitmap, with its transparency set to alpha8 pixel value.

## Color Type BGR 565 BGR 565 is a 16-bit word pixel encoding that contains five bits of blue, six bits of green, and five bits of red. BGR 565 is fully opaque as if its Color Alpha was set to one, and should always be paired with kOpaque_SkAlphaType. ![Color_Type_BGR_565](https://fiddle.skia.org/i/b674a54eb4188d5ce66c04cebdb61089_raster.png "") ### Example

## Color Type ABGR 4444 ABGR 4444 is a 16-bit word pixel encoding that contains four bits of alpha, four bits of blue, four bits of green, and four bits of red. ![Color_Type_ABGR_4444](https://fiddle.skia.org/i/0441bdba65a19aa72b75b7fa62d22121_raster.png "") If paired with kPremul_SkAlphaType: blue, green, and red components are premultiplied by the alpha value. If blue, green, or red is greater than alpha, the drawn result is undefined. If paired with kUnpremul_SkAlphaType: alpha, blue, green, and red components may have any value. There may be a performance penalty with unpremultipled pixels. If paired with kOpaque_SkAlphaType: all alpha component values are at the maximum; blue, green, and red components are fully opaque. If any alpha component is less than 15, the drawn result is undefined. ### Example

## Color Type RGBA 8888 RGBA 8888 is a 32-bit word pixel encoding that contains eight bits of red, eight bits of green, eight bits of blue, and eight bits of alpha. ![Color_Type_RGBA_8888](https://fiddle.skia.org/i/4ccd35f27fe73dce8cce8c75e18df23c_raster.png "") If paired with kPremul_SkAlphaType: red, green, and blue components are premultiplied by the alpha value. If red, green, or blue is greater than alpha, the drawn result is undefined. If paired with kUnpremul_SkAlphaType: alpha, red, green, and blue components may have any value. There may be a performance penalty with unpremultipled pixels. If paired with kOpaque_SkAlphaType: all alpha component values are at the maximum; red, green, and blue components are fully opaque. If any alpha component is less than 255, the drawn result is undefined. On Big_Endian platforms, RGBA 8888 is the native Color Type, and will have the best performance. Use kN32_SkColorType to choose the best Color Type for the platform at compile time. ### Example

## Color Type RGB 888x RGB 888x is a 32-bit word pixel encoding that contains eight bits of red, eight bits of green, eight bits of blue, and eight unused bits. RGB 888x is fully opaque as if its Color Alpha was set to one, and should always be paired with kOpaque_SkAlphaType. ![Color_Type_RGB_888x](https://fiddle.skia.org/i/fecfe58c25cfc1b1e411e5eb50f7d8d1_raster.png "") ### Example

## Color Type BGRA 8888 BGRA 8888 is a 32-bit word pixel encoding that contains eight bits of blue, eight bits of green, eight bits of red, and eight bits of alpha. ![Color_Type_BGRA_8888](https://fiddle.skia.org/i/babd0e12db21a88c74d4e88aa40268ab_raster.png "") If paired with kPremul_SkAlphaType: blue, green, and red components are premultiplied by the alpha value. If blue, green, or red is greater than alpha, the drawn result is undefined. If paired with kUnpremul_SkAlphaType: blue, green, red, and alpha components may have any value. There may be a performance penalty with unpremultipled pixels. If paired with kOpaque_SkAlphaType: all alpha component values are at the maximum; blue, green, and red components are fully opaque. If any alpha component is less than 255, the drawn result is undefined. On Little_Endian platforms, BGRA 8888 is the native Color Type, and will have the best performance. Use kN32_SkColorType to choose the best Color Type for the platform at compile time. ### Example

## Color Type RGBA 1010102 RGBA 1010102 is a 32-bit word pixel encoding that contains ten bits of red, ten bits of green, ten bits of blue, and two bits of alpha. Possible alpha values are zero: fully transparent; one: 33% opaque; two: 67% opaque; three: fully opaque. ![Color_Type_RGBA_1010102](https://fiddle.skia.org/i/6c470410001ad8f1ee9f58204c66f1bb_raster.png "") If paired with kPremul_SkAlphaType: red, green, and blue components are premultiplied by the alpha value. If red, green, or blue is greater than the alpha replicated to ten bits, the drawn result is undefined. If paired with kUnpremul_SkAlphaType: alpha, red, green, and blue components may have any value. There may be a performance penalty with unpremultipled pixels. If paired with kOpaque_SkAlphaType: all alpha component values are at the maximum; red, green, and blue components are fully opaque. If any alpha component is less than 3, the drawn result is undefined. ### Example

## Color Type RGB 101010x ![Color_Type_RGB_101010x](https://fiddle.skia.org/i/c22477b11dabaa3e3a0b5bb33a7733cd_raster.png "") ### Example

## Color Type Gray 8 ### Example

## Color Type RGBA F16 ![Color_Type_RGBA_F16](https://fiddle.skia.org/i/9344796c059ff5e4f057595e781905b3_raster.png "") ### Example

## YUV ColorSpace ## 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.

### Example

### See Also incomplete ## Enum SkDestinationSurfaceColorMode

enum class SkDestinationSurfaceColorMode {
kLegacy,
kGammaAndColorSpaceAware,
};

### Constants

`SkDestinationSurfaceColorMode::kLegacy`	0
`SkDestinationSurfaceColorMode::kGammaAndColorSpaceAware`	1

### Example

### See Also incomplete # Struct SkImageInfo Describes Image dimensions and pixel type. Used for both source images and render-targets (surfaces). ## Member Function | name | description | | --- | --- | | ByteSizeOverflowed | incomplete | | 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 | incomplete | | bounds | incomplete | | bytesPerPixel | incomplete | | colorSpace | incomplete | | colorType | incomplete | | computeByteSize | incomplete | | computeMinByteSize | incomplete | | computeOffset | incomplete | | dimensions | incomplete | | flatten | incomplete | | gammaCloseToSRGB | incomplete | | height | incomplete | | isEmpty | incomplete | | isOpaque | incomplete | | 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 | incomplete | | minRowBytes64 | incomplete | | refColorSpace | incomplete | | reset | incomplete | | shiftPerPixel | incomplete | | unflatten | incomplete | | validRowBytes | incomplete | | validate | incomplete | | width | incomplete | ## Related Function | name | description | | --- | --- | | Property | metrics and attributes | | Utility | rarely called management functions | ## Constructor | 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 | | | MakeN32Premul(int width, int height, sk sp<SkColorSpace> cs = nullptr) | | | MakeN32Premul(const SkISize& size) | | MakeS32 | creates Image Info with Native Color Type, sRGB Color Space | | MakeUnknown | creates Image Info with kUnknown_SkColorType, kUnknown_SkAlphaType | | | MakeUnknown(int width, int height) | | | MakeUnknown() | | 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 | | reset | incomplete | ## SkImageInfo

SkImageInfo()

### Return Value incomplete ### Example

### See Also incomplete --- ## 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 incomplete ### Example

### See Also incomplete --- ## MakeN32

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

Sets Color Type to kN32_SkColorType. ### Parameters

`width`	incomplete
`height`	incomplete
`at`	incomplete
`cs`	incomplete

### Return Value incomplete ### Example

### See Also incomplete --- ## 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 incomplete ### Example

### See Also incomplete --- ## MakeN32Premul

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

Sets Color Type to kN32_SkColorType, and the Alpha Type to kPremul_SkAlphaType. ### Parameters

`width`	incomplete
`height`	incomplete
`cs`	incomplete

### Return Value incomplete ### Example

### See Also incomplete ---

static SkImageInfo MakeN32Premul(const SkISize& size)

### Parameters

size incomplete

### Return Value incomplete ### Example

### See Also incomplete --- ## MakeA8

static SkImageInfo MakeA8(int width, int height)

### Parameters

`width`	incomplete
`height`	incomplete

### Return Value incomplete ### Example

### See Also incomplete --- ## MakeUnknown

static SkImageInfo MakeUnknown(int width, int height)

### Parameters

`width`	incomplete
`height`	incomplete

### Return Value incomplete ### Example

### See Also incomplete ---

static SkImageInfo MakeUnknown()

### Return Value incomplete ### Example

### See Also incomplete --- ## Property | name | description | | --- | --- | | alphaType | incomplete | | bounds | incomplete | | bytesPerPixel | incomplete | | colorSpace | incomplete | | colorType | incomplete | | dimensions | incomplete | | gammaCloseToSRGB | incomplete | | height | incomplete | | isEmpty | incomplete | | isOpaque | incomplete | | minRowBytes | incomplete | | minRowBytes64 | incomplete | | refColorSpace | incomplete | | shiftPerPixel | incomplete | | width | incomplete | ## width

int width() const

### Return Value incomplete ### Example

### See Also incomplete --- ## height

int height() const

### Return Value incomplete ### Example

### See Also incomplete --- ## colorType

SkColorType colorType() const

### Return Value incomplete ### Example

### See Also incomplete --- ## alphaType

SkAlphaType alphaType() const

### Return Value incomplete ### Example

### See Also incomplete --- ## colorSpace

SkColorSpace* colorSpace() const

### Return Value incomplete ### Example

### See Also incomplete --- ## refColorSpace

sk_sp<SkColorSpace> refColorSpace() const

### Return Value incomplete ### Example

### See Also incomplete --- ## isEmpty

bool isEmpty() const

### Return Value incomplete ### Example

### See Also incomplete --- ## isOpaque

bool isOpaque() const

### Return Value incomplete ### Example

### See Also incomplete --- ## dimensions

SkISize dimensions() const

### Return Value incomplete ### Example

### See Also incomplete --- ## bounds

SkIRect bounds() const

### Return Value incomplete ### Example

### See Also incomplete --- ## gammaCloseToSRGB

bool gammaCloseToSRGB() const

### Return Value incomplete ### Example

### See Also incomplete --- ## makeWH

SkImageInfo makeWH(int newWidth, int newHeight) const

Creates Image Info with the same Color Type and Alpha Type as this info, but with the specified width and height. ### Parameters

`newWidth`	incomplete
`newHeight`	incomplete

### Return Value incomplete ### Example

### See Also incomplete --- ## makeAlphaType

SkImageInfo makeAlphaType(SkAlphaType newAlphaType) const

### Parameters

newAlphaType incomplete

### Return Value incomplete ### Example

### See Also incomplete --- ## makeColorType

SkImageInfo makeColorType(SkColorType newColorType) const

### Parameters

newColorType incomplete

### Return Value incomplete ### Example

### See Also incomplete --- ## makeColorSpace

SkImageInfo makeColorSpace(sk_sp<SkColorSpace> cs) const

### Parameters

`cs`	incomplete

### Return Value incomplete ### Example

### See Also incomplete --- ## bytesPerPixel

int bytesPerPixel() const

### Return Value incomplete ### Example

### See Also incomplete --- ## shiftPerPixel

int shiftPerPixel() const

### Return Value incomplete ### Example

### See Also incomplete --- ## minRowBytes64

uint64_t minRowBytes64() const

### Return Value incomplete ### Example

### See Also incomplete --- ## minRowBytes

size_t minRowBytes() const

### Return Value incomplete ### Example

### See Also incomplete --- ## computeOffset

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

### Parameters

`x`	incomplete
`y`	incomplete
`rowBytes`	incomplete

### Return Value incomplete ### Example

### See Also incomplete --- ## Operator | name | description | | --- | --- | | operator!=(const SkImageInfo& other) const | incomplete | | operator==(const SkImageInfo& other) const | incomplete | ## operator==

bool operator==(const SkImageInfo& other) _const

### Parameters

other incomplete

### Return Value incomplete ### Example

### See Also incomplete --- ## operator!=

bool operator!=(const SkImageInfo& other) _const

### Parameters

other incomplete

### Return Value incomplete ### Example

### See Also incomplete --- ## unflatten

void unflatten(SkReadBuffer& buffer)

### Parameters

buffer incomplete

### Example

### See Also incomplete --- ## flatten

void flatten(SkWriteBuffer& buffer) const

### Parameters

buffer incomplete

### Example

### See Also incomplete --- ## 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 incomplete

### Return Value incomplete ### Example

### See Also incomplete --- ## 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 incomplete ### Example

### See Also incomplete --- ## ByteSizeOverflowed

static bool ByteSizeOverflowed(size_t byteSize)

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

byteSize incomplete

### Return Value incomplete ### Example

### See Also incomplete --- ## validRowBytes

bool validRowBytes(size_t rowBytes) const

### Parameters

rowBytes incomplete

### Return Value incomplete ### Example

### See Also incomplete --- ## reset

void reset()

### Example

### See Also incomplete --- ## Utility | name | description | | --- | --- | | ByteSizeOverflowed | incomplete | | computeByteSize | incomplete | | computeMinByteSize | incomplete | | computeOffset | incomplete | | flatten | incomplete | | unflatten | incomplete | | validRowBytes | incomplete | | validate | incomplete | ## validate

void validate() const

### Example

### See Also incomplete ---