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
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
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
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
Alpha Type Unpremul
Use Unpremul if stored color components are not divided by the alpha component. Some drawing destinations may not support Unpremul.
Example
SkAlphaTypeIsOpaque
Returns true if Alpha Type equals kOpaque_SkAlphaType. kOpaque_SkAlphaType is a hint that the Color Type is opaque, or that all Color Alpha values are set to their 1.0 equivalent. If Alpha Type is kOpaque_SkAlphaType, and Color Type is not opaque, then the result of drawing any pixel with a Color Alpha value less than 1.0 is undefined.
Parameters
Return Value
true if at equals kOpaque_SkAlphaType
Color Type
Color Type Native
Enum 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
Constants
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
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.
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.
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.
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.
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.
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.
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
RGB 101010x is a 32-bit word pixel encoding that contains ten bits of red, ten bits of green, ten bits of blue, and two unused bits. RGB 101010x is fully opaque as if its Color Alpha was set to one, and should always be paired with kOpaque_SkAlphaType.
Example
Color Type Gray 8
Gray 8 is an 8-bit byte pixel encoding that represents equal values for red, blue, and green, reprsenting colors from black to white. Gray 8 is fully opaque as if its Color Alpha was set to one, and should always be paired with kOpaque_SkAlphaType.
Example
Color Type RGBA F16
RGBA F16 is a 64-bit word pixel encoding that contains sixteen bits of blue, sixteen bits of green, sixteen bits of red, and sixteen bits of alpha.
Each component encodes a floating point value using Half floats . Meaningful colors are represented by the range 0.0 to 1.0, although smaller and larger values may be useful when used in combination with Transfer Mode.
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.
Example
SkColorTypeBytesPerPixel
Returns the number of bytes required to store a pixel, including unused padding. Returns zero if ct is kUnknown_SkColorType or invalid.
Parameters
Return Value
bytes per pixel
Example
See Also
SkImageInfo::bytesPerPixel
SkColorTypeIsAlwaysOpaque
Returns true if Color Type always decodes Color Alpha to 1.0, making the pixel fully opaque. If true, Color Type does not reserve bits to encode Color Alpha.
Parameters
Return Value
true if Color Alpha is always set to 1.0
Example
See Also
SkColorTypeValidateAlphaType
SkColorTypeValidateAlphaType
Returns true if canonical can be set to a valid Alpha Type for colorType. If there is more than one valid canonical Alpha Type, set to alphaType, if valid. If true is returned and canonical is not nullptr, store valid Alpha Type.
Returns false only if alphaType is kUnknown_SkAlphaType, color type is not kUnknown_SkColorType, and Color Type is not always opaque. If false is returned, canonical is ignored.
For kUnknown_SkColorType: set canonical to kUnknown_SkAlphaType and return true. For kAlpha_8_SkColorType: set canonical to kPremul_SkAlphaType or kOpaque_SkAlphaType and return true if alphaType is not kUnknown_SkAlphaType. For kRGB_565_SkColorType, kRGB_888x_SkColorType, kRGB_101010x_SkColorType, and kGray_8_SkColorType: set canonical to kOpaque_SkAlphaType and return true. For kARGB_4444_SkColorType, kRGBA_8888_SkColorType, kBGRA_8888_SkColorType, kRGBA_1010102_SkColorType, and kRGBA_F16_SkColorType: set canonical to alphaType and return true if alphaType is not kUnknown_SkAlphaType.
Parameters
Return Value
true if valid Alpha Type can be associated with colorType
Example
See Also
SkColorTypeIsAlwaysOpaque
YUV ColorSpace
Enum SkYUVColorSpace
Describes color range of YUV pixels. The color mapping from YUV to RGB varies depending on the source. YUV pixels may be generated by JPEG images, standard video streams, or high definition video streams. Each has its own mapping from YUV and RGB.
JPEG YUV values encode the full range of 0 to 255 for all three components. Video YUV values range from 16 to 235 for all three components. Details of encoding and conversion to RGB are described in YCbCr color space .
Constants
with full range of 0 to 255 for components.
with studio range of 16 to 235 range for components.
with studio range of 16 to 235 range for components.
See Also
SkImage::MakeFromYUVTexturesCopy SkImage::MakeFromNV12TexturesCopy
Struct SkImageInfo
Describes pixel dimensions and encoding. Bitmap, Image, PixMap, and Surface can be created from Image Info. Image Info can be retrieved from Bitmap and Pixmap, but not from Image and Surface. For example, Image and Surface implementations may defer pixel depth, so may not completely specify Image Info.
Image Info contains dimensions, the pixel integral width and height. It encodes how pixel bits describe Color Alpha, transparency; Color components red, blue, and green; and Color Space, the range and linearity of colors.
Member Function
| name | description |
|---|---|
| ByteSizeOverflowed | checks result of computeByteSize and computeMinByteSize |
| 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 | Returns Alpha Type |
| bounds | returns width and height as Rectangle |
| bytesPerPixel | returns number of bytes in pixel based on Color Type |
| colorSpace | returns Color Space |
| colorType | returns Color Type |
| computeByteSize | memory required by pixel buffer with given row bytes |
| computeMinByteSize | least memory required by pixel buffer |
| computeOffset | returns byte offset within pixel array |
| dimensions | returns width and height |
| gammaCloseToSRGB | Returns if Color Space gamma is approximately the same as sRGB |
| height | returns pixel row count |
| isEmpty | returns if dimensions contain pixels |
| isOpaque | returns if Alpha Type is kOpaque_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 |
| minRowBytes | returns width times bytesPerPixel in 32 bits |
| minRowBytes64 | returns width times bytesPerPixel in 64 bits |
| refColorSpace | returns Color Space |
| reset | sets zero dimensions, kUnknown_SkColorType, kUnknown_SkAlphaType |
| shiftPerPixel | returns bit shift from pixels to bytes |
| validRowBytes | checks if row bytes is large enough to contain pixel row |
| validate | asserts if Image Info is invalid (debug only) |
| width | returns pixel column count |
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 | sets zero dimensions, kUnknown_SkColorType, kUnknown_SkAlphaType |
SkImageInfo
Creates an empty Image Info with kUnknown_SkColorType, kUnknown_SkAlphaType, a width and height of zero, and no Color Space.
Return Value
empty Image Info
Example
See Also
Make MakeN32 MakeS32 MakeA8
Make
Creates Image Info from integral dimensions width and height, Color Type ct, Alpha Type at, and optionally Color Space cs.
If Color Space cs is nullptr and Image Info is part of drawing source: Color Space defaults to sRGB, mapping into Surface Color Space.
Parameters are not validated to see if their values are legal, or that the combination is supported.
Parameters
Return Value
created Image Info
Example
See Also
MakeN32 MakeN32Premul[2] MakeS32 MakeA8
MakeN32
Creates Image Info from integral dimensions width and height, kN32_SkColorType, Alpha Type at, and optionally Color Space cs. kN32_SkColorType will equal either kBGRA_8888_SkColorType or kRGBA_8888_SkColorType, whichever is optimal.
If Color Space cs is nullptr and Image Info is part of drawing source: Color Space defaults to sRGB, mapping into Surface Color Space.
Parameters are not validated to see if their values are legal, or that the combination is supported.
Parameters
Return Value
created Image Info
Example
See Also
Make MakeN32Premul[2] MakeS32 MakeA8
MakeS32
Creates Image Info from integral dimensions width and height, kN32_SkColorType, Alpha Type at, with sRGB Color Space.
Parameters are not validated to see if their values are legal, or that the combination is supported.
Parameters
Return Value
created Image Info
Example
See Also
Make MakeN32 MakeN32Premul[2] MakeA8
MakeN32Premul
Creates Image Info from integral dimensions width and height, kN32_SkColorType, kPremul_SkAlphaType, with optional Color Space.
If Color Space cs is nullptr and Image Info is part of drawing source: Color Space defaults to sRGB, mapping into Surface Color Space.
Parameters are not validated to see if their values are legal, or that the combination is supported.
Parameters
Return Value
created Image Info
Example
See Also
MakeN32 MakeS32 MakeA8 Make
Creates Image Info from integral dimensions width and height, kN32_SkColorType, kPremul_SkAlphaType, with Color Space set to nullptr.
If Image Info is part of drawing source: Color Space defaults to sRGB, mapping into Surface Color Space.
Parameters are not validated to see if their values are legal, or that the combination is supported.
Parameters
Return Value
created Image Info
Example
See Also
MakeN32 MakeS32 MakeA8 Make
MakeA8
Creates Image Info from integral dimensions width and height, kAlpha_8_SkColorType, kPremul_SkAlphaType, with Color Space set to nullptr.
Parameters
Return Value
created Image Info
Example
See Also
MakeN32 MakeS32 Make
MakeUnknown
Creates Image Info from integral dimensions width and height, kUnknown_SkColorType, kUnknown_SkAlphaType, with Color Space set to nullptr.
Returned Image Info as part of source does not draw, and as part of destination can not be drawn to.
Parameters
Return Value
created Image Info
Example
See Also
SkImageInfo() MakeN32 MakeS32 Make
Creates Image Info from integral dimensions width and height set to zero, kUnknown_SkColorType, kUnknown_SkAlphaType, with Color Space set to nullptr.
Returned Image Info as part of source does not draw, and as part of destination can not be drawn to.
Return Value
created Image Info
Example
See Also
SkImageInfo() MakeN32 MakeS32 Make
Property
| name | description |
|---|---|
| alphaType | Returns Alpha Type |
| bounds | returns width and height as Rectangle |
| bytesPerPixel | returns number of bytes in pixel based on Color Type |
| colorSpace | returns Color Space |
| colorType | returns Color Type |
| dimensions | returns width and height |
| gammaCloseToSRGB | Returns if Color Space gamma is approximately the same as sRGB |
| height | returns pixel row count |
| isEmpty | returns if dimensions contain pixels |
| isOpaque | returns if Alpha Type is kOpaque_SkAlphaType |
| minRowBytes | returns width times bytesPerPixel in 32 bits |
| minRowBytes64 | returns width times bytesPerPixel in 64 bits |
| refColorSpace | returns Color Space |
| shiftPerPixel | returns bit shift from pixels to bytes |
| width | returns pixel column count |
width
Returns pixel count in each row.
Return Value
pixel width
Example
See Also
height SkBitmap::width SkPixelRef::width SkImage::width SkSurface::width
height
Returns pixel row count.
Return Value
pixel height
Example
See Also
width SkBitmap::height SkPixelRef::height SkImage::height SkSurface::height
colorType
Returns Color Type, 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.
Return Value
Color Type
Example
Example Output
color type: kAlpha_8_SkColorType
See Also
alphaType SkPixmap::colorType SkBitmap::colorType
alphaType
Returns Alpha Type, one of: kUnknown_SkAlphaType, kOpaque_SkAlphaType, kPremul_SkAlphaType, kUnpremul_SkAlphaType.
Return Value
Alpha Type
Example
Example Output
alpha type: kPremul_SkAlphaType
See Also
colorType SkPixmap::alphaType SkBitmap::alphaType
colorSpace
Returns Color Space, the range of colors. The reference count of Color Space is unchanged. The returned Color Space is immutable.
Return Value
Color Space, or nullptr
Example
Example Output
gammaCloseToSRGB: false gammaIsLinear: true isSRGB: false
See Also
Color Space SkPixmap::colorSpace SkBitmap::colorSpace
refColorSpace
Returns smart pointer to Color Space, the range of colors. The smart pointer tracks the number of objects sharing this Color Space reference so the memory is released when the owners destruct.
The returned Color Space is immutable.
Return Value
Color Space wrapped in a smart pointer
Example
See Also
Color Space SkBitmap::refColorSpace
isEmpty
Returns if Image Info describes an empty area of pixels by checking if either width or height is zero or smaller.
Return Value
true if either dimension is zero or smaller
Example
Example Output
width: 0 height: 0 empty: true width: 0 height: 2 empty: true width: 2 height: 0 empty: true width: 2 height: 2 empty: false
See Also
dimensions bounds SkBitmap::empty SkPixmap::bounds
isOpaque
Returns true if Alpha Type is set to hint that all pixels are opaque; their Color Alpha value is implicitly or explicitly 1.0. If true, and all pixels are not opaque, Skia may draw incorrectly.
Does not check if Color Type allows Alpha, or if any pixel value has transparency.
Return Value
true if Alpha Type is kOpaque_SkAlphaType
Example
Example Output
isOpaque: false isOpaque: false isOpaque: true isOpaque: true
See Also
Color Alpha SkColorTypeValidateAlphaType SkBitmap::isOpaque SkImage::isOpaque SkPixmap::isOpaque
dimensions
Returns ISize { width, height }.
Return Value
integral size of width and height
Example
Example Output
dimensionsAsBounds == bounds
See Also
width height bounds SkBitmap::dimensions
bounds
Returns IRect { 0, 0, width, height }.
Return Value
integral rectangle from origin to width and height
Example
See Also
width height dimensions
gammaCloseToSRGB
Returns true if associated Color Space is not nullptr, and Color Space gamma is approximately the same as sRGB. This includes the sRGB transfer function $ https://en.wikipedia.org/wiki/SRGB#The_sRGB_transfer_function_(%22gamma%22) as well as a gamma curve described by a 2.2 exponent.
Return Value
true if Color Space gamma is approximately the same as sRGB
Example
See Also
SkColorSpace::gammaCloseToSRGB
makeWH
Creates Image Info with the same Color Type, Color Space, and Alpha Type, with dimensions set to width and height.
Parameters
Return Value
created Image Info
Example
See Also
Make makeAlphaType makeColorSpace makeColorType
makeAlphaType
Creates Image Info with same Color Type, Color Space, width, and height, with Alpha Type set to newAlphaType.
Created Image Info contains newAlphaType even if it is incompatible with Color Type, in which case Alpha Type in Image Info is ignored.
Parameters
Return Value
created Image Info
Example
See Also
Make MakeA8 makeColorType makeColorSpace
makeColorType
Creates Image Info with same Alpha Type, Color Space, width, and height, with Color Type set to newColorType.
Parameters
Return Value
created Image Info
Example
See Also
Make makeAlphaType makeColorSpace
makeColorSpace
Creates Image Info with same Alpha Type, Color Type, width, and height, with Color Space set to cs.
Parameters
Return Value
created Image Info
Example
See Also
Make MakeS32 makeAlphaType makeColorType
bytesPerPixel
Returns number of bytes per pixel required by Color Type. Returns zero if colorType( is kUnknown_SkColorType.
Return Value
bytes in pixel
Example
Example Output
color: kUnknown_SkColorType bytesPerPixel: 0 color: kAlpha_8_SkColorType bytesPerPixel: 1 color: kRGB_565_SkColorType bytesPerPixel: 2 color: kARGB_4444_SkColorType bytesPerPixel: 2 color: kRGBA_8888_SkColorType bytesPerPixel: 4 color: kRGB_888x_SkColorType bytesPerPixel: 4 color: kBGRA_8888_SkColorType bytesPerPixel: 4 color: kRGBA_1010102_SkColorType bytesPerPixel: 4 color: kRGB_101010x_SkColorType bytesPerPixel: 4 color: kGray_8_SkColorType bytesPerPixel: 1 color: kRGBA_F16_SkColorType bytesPerPixel: 8
See Also
width shiftPerPixel SkBitmap::bytesPerPixel
shiftPerPixel
Returns bit shift converting row bytes to row pixels. Returns zero for kUnknown_SkColorType.
Return Value
one of: 0, 1, 2, 3; left shift to convert pixels to bytes
Example
Example Output
color: kUnknown_SkColorType shiftPerPixel: 0 color: kAlpha_8_SkColorType shiftPerPixel: 0 color: kRGB_565_SkColorType shiftPerPixel: 1 color: kARGB_4444_SkColorType shiftPerPixel: 1 color: kRGBA_8888_SkColorType shiftPerPixel: 2 color: kRGB_888x_SkColorType shiftPerPixel: 2 color: kBGRA_8888_SkColorType shiftPerPixel: 2 color: kRGBA_1010102_SkColorType shiftPerPixel: 2 color: kRGB_101010x_SkColorType shiftPerPixel: 2 color: kGray_8_SkColorType shiftPerPixel: 0 color: kRGBA_F16_SkColorType shiftPerPixel: 3
See Also
bytesPerPixel minRowBytes SkBitmap::shiftPerPixel SkPixmap::shiftPerPixel
minRowBytes64
Returns minimum bytes per row, computed from pixel width and Color Type, which specifies bytesPerPixel. Bitmap maximum value for row bytes must be representable as a positive value in a 32-bit signed integer.
Return Value
width times bytesPerPixel as unsigned 64-bit integer
Example
Example Output
RGBA_F16 width 16777216 (0x01000000) OK RGBA_F16 width 33554432 (0x02000000) OK RGBA_F16 width 67108864 (0x04000000) OK RGBA_F16 width 134217728 (0x08000000) OK RGBA_F16 width 268435456 (0x10000000) too large RGBA_F16 width 536870912 (0x20000000) too large RGBA_F16 width 1073741824 (0x40000000) too large RGBA_F16 width -2147483648 (0x80000000) too large
See Also
minRowBytes computeByteSize computeMinByteSize validRowBytes
minRowBytes
Returns minimum bytes per row, computed from pixel width and Color Type, which specifies bytesPerPixel. Bitmap maximum value for row bytes must be representable as a positive value in a 32-bit signed integer.
Return Value
width times bytesPerPixel as signed 32-bit integer
Example
Example Output
RGBA_F16 width 16777216 (0x01000000) OK RGBA_F16 width 33554432 (0x02000000) OK RGBA_F16 width 67108864 (0x04000000) OK RGBA_F16 width 134217728 (0x08000000) OK RGBA_F16 width 268435456 (0x10000000) too large RGBA_F16 width 536870912 (0x20000000) too large RGBA_F16 width 1073741824 (0x40000000) too large RGBA_F16 width -2147483648 (0x80000000) too large
See Also
minRowBytes64 computeByteSize computeMinByteSize validRowBytes
computeOffset
Returns byte offset of pixel from pixel base address.
Asserts in debug build if x or y is outside of bounds. Does not assert if rowBytes is smaller than minRowBytes, even though result may be incorrect.
Parameters
Return Value
offset within pixel array
Example
See Also
height width minRowBytes computeByteSize
Operator
| name | description |
|---|---|
| operator!=(const SkImageInfo& other) const | compares Image Info for inequality |
| operator==(const SkImageInfo& other) const | compares Image Info for equality |
operator==
Compares Image Info with other, and returns true if width, height, Color Type, Alpha Type, and Color Space are equivalent.
Parameters
Return Value
true if Image Info equals other
Example
Example Output
info1 != info2 info1 != info2 info1 != info2 info1 == info2
See Also
operator!=(const SkImageInfo& other) const SkColorSpace::Equals
operator!=
Compares Image Info with other, and returns true if width, height, Color Type, Alpha Type, and Color Space are equivalent.
Parameters
Return Value
true if Image Info is not equal to other
Example
Example Output
info1 != info2 info1 != info2 info1 != info2 info1 == info2
See Also
operator==(const SkImageInfo& other) const SkColorSpace::Equals
computeByteSize
Returns storage required by pixel array, given Image Info dimensions, Color Type, and rowBytes. rowBytes is assumed to be at least as large as minRowBytes.
Returns zero if height is zero. Returns SK MaxSizeT if answer exceeds the range of size_t.
Parameters
Return Value
memory required by pixel buffer
Example
See Also
computeMinByteSize validRowBytes
computeMinByteSize
Returns storage required by pixel array, given Image Info dimensions, and Color Type. Uses minRowBytes to compute bytes for pixel row.
Returns zero if height is zero. Returns SK MaxSizeT if answer exceeds the range of size_t.
Return Value
least memory required by pixel buffer
Example
See Also
computeByteSize validRowBytes
ByteSizeOverflowed
Returns true if byteSize equals SK MaxSizeT. computeByteSize and computeMinByteSize return SK MaxSizeT if size_t can not hold buffer size.
Parameters
Return Value
true if computeByteSize or computeMinByteSize result exceeds size_t
Example
Example Output
rowBytes:100000000 size:99999999900000008 overflowed:false rowBytes:1000000000 size:999999999000000008 overflowed:false rowBytes:10000000000 size:9999999990000000008 overflowed:false rowBytes:100000000000 size:18446744073709551615 overflowed:true rowBytes:1000000000000 size:18446744073709551615 overflowed:true
See Also
computeByteSize computeMinByteSize validRowBytes
validRowBytes
Returns true if rowBytes is smaller than width times pixel size.
Parameters
Return Value
true if rowBytes is large enough to contain pixel row
Example
Example Output
validRowBytes(60): false validRowBytes(64): true validRowBytes(68): true
See Also
ByteSizeOverflowed computeByteSize computeMinByteSize
reset
Creates an empty Image Info with kUnknown_SkColorType, kUnknown_SkAlphaType, a width and height of zero, and no Color Space.
Example
Example Output
info == copy info != reset copy SkImageInfo() == reset copy
See Also
SkImageInfo()
Utility
| name | description |
|---|---|
| ByteSizeOverflowed | checks result of computeByteSize and computeMinByteSize |
| computeByteSize | memory required by pixel buffer with given row bytes |
| computeMinByteSize | least memory required by pixel buffer |
| computeOffset | returns byte offset within pixel array |
| validRowBytes | checks if row bytes is large enough to contain pixel row |
| validate | asserts if Image Info is invalid (debug only) |
validate
Asserts if internal values are illegal or inconsistent. Only available if SK_DEBUG is defined at compile time.
See Also
validRowBytes SkBitmap::validate