ImageInfo

class ImageInfo

Describes pixel dimensions and encoding.

Bitmap, Image, Pixmap, and Surface can be created from ImageInfo. ImageInfo 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 ImageInfo.

ImageInfo contains dimensions, the pixel integral width and height. It encodes how pixel bits describe alpha, transparency; color components red, blue, and green; and ColorSpace, the range and linearity of colors.

Methods

`ByteSizeOverflowed`	Returns true if byteSize equals SIZE_MAX.
`Make`	Overloaded function.
`MakeA8`	Overloaded function.
`MakeN32`	Creates `ImageInfo` from integral dimensions width and height, `kN32_ColorType`, `AlphaType` at, and optionally `ColorSpace` cs.
`MakeN32Premul`	Overloaded function.
`MakeS32`	Creates `ImageInfo` from integral dimensions width and height, `kN32_ColorType`, `AlphaType` at, with sRGB `ColorSpace`.
`MakeUnknown`	Overloaded function.
`__init__`	Creates an empty `ImageInfo` with `kUnknown_ColorType`, `kUnknown_AlphaType`, a width and height of zero, and no `ColorSpace`.
`alphaType`
`bounds`	Returns `IRect` (0, 0, `width()`, `height()`).
`bytesPerPixel`	Returns number of bytes per pixel required by `ColorType`.
`colorInfo`	Returns the dimensionless `ColorInfo` that represents the same color type, alpha type, and color space as this `ImageInfo`.
`colorSpace`	Returns `ColorSpace`, the range of colors.
`colorType`
`computeByteSize`	Returns storage required by pixel array, given `ImageInfo` dimensions, `ColorType`, and rowBytes.
`computeMinByteSize`	Returns storage required by pixel array, given `ImageInfo` dimensions, and `ColorType`.
`computeOffset`	Returns byte offset of pixel from pixel base address.
`dimensions`	Returns `ISize` (`width()`, `height()`).
`gammaCloseToSRGB`	Returns true if associated `ColorSpace` is not nullptr, and `ColorSpace` gamma is approximately the same as sRGB.
`height`	Returns pixel row count.
`isEmpty`	Returns if `ImageInfo` describes an empty area of pixels by checking if either width or height is zero or smaller.
`isOpaque`	Returns true if `AlphaType` is set to hint that all pixels are opaque; their alpha value is implicitly or explicitly 1.0.
`makeAlphaType`	Creates `ImageInfo` with same `ColorType`, `ColorSpace`, width, and height, with `AlphaType` set to newAlphaType.
`makeColorSpace`	Creates `ImageInfo` with same `AlphaType`, `ColorType`, width, and height, with `ColorSpace` set to cs.
`makeColorType`	Creates `ImageInfo` with same `AlphaType`, `ColorSpace`, width, and height, with `ColorType` set to newColorType.
`makeDimensions`	Creates `ImageInfo` with the same `ColorType`, `ColorSpace`, and `AlphaType`, with dimensions set to newDimensions.
`makeWH`	Creates `ImageInfo` with the same `ColorType`, `ColorSpace`, and `AlphaType`, with dimensions set to width and height.
`minRowBytes`	Returns minimum bytes per row, computed from pixel `width()` and `ColorType`, which specifies `bytesPerPixel()`.
`minRowBytes64`	Returns minimum bytes per row, computed from pixel `width()` and `ColorType`, which specifies `bytesPerPixel()`.
`refColorSpace`	Returns smart pointer to `ColorSpace`, the range of colors.
`reset`	Creates an empty `ImageInfo` with `kUnknown_ColorType`, `kUnknown_AlphaType`, a width and height of zero, and no `ColorSpace`.
`shiftPerPixel`	Returns bit shift converting row bytes to row pixels.
`validRowBytes`	Returns true if rowBytes is valid for this `ImageInfo`.
`width`	Returns pixel count in each row.

Methods

static ImageInfo.ByteSizeOverflowed(byteSize: int) → bool

Returns true if byteSize equals SIZE_MAX.

computeByteSize() and computeMinByteSize() return SIZE_MAX if size_t can not hold buffer size.

Parameters:: byteSize (int) – result of computeByteSize() or computeMinByteSize()
Returns:: true if computeByteSize() or computeMinByteSize() result exceeds size_t

static ImageInfo.Make(*args, **kwargs)

Overloaded function.

Make(width: int, height: int, ct: skia.ColorType, at: skia.AlphaType, cs: skia.ColorSpace = None) -> skia.ImageInfo

Creates ImageInfo from integral dimensions width and height, ColorType ct, AlphaType at, and optionally ColorSpace cs.

If ColorSpace cs is nullptr and ImageInfo is part of drawing source: ColorSpace defaults to sRGB, mapping into Surface ColorSpace.

Parameters are not validated to see if their values are legal, or that the combination is supported.

width:

pixel column count; must be zero or greater

height:

pixel row count; must be zero or greater

cs:

range of colors; may be nullptr

return:

created ImageInfo
Make(dimensions: skia.ISize, ct: skia.ColorType, at: skia.AlphaType, cs: skia.ColorSpace = None) -> skia.ImageInfo
Make(dimensions: skia.ISize, colorInfo: skia.ColorInfo) -> skia.ImageInfo

Creates ImageInfo from integral dimensions and ColorInfo colorInfo,.

Parameters are not validated to see if their values are legal, or that the combination is supported.

param skia.ISize dimensions:

pixel column and row count; must be zeros or greater

param skia.ColorInfo colorInfo:

ColorInfo the pixel encoding consisting of ColorType, AlphaType, and ColorSpace (which may be nullptr)

return:

created ImageInfo

static ImageInfo.MakeA8(*args, **kwargs)

Overloaded function.

MakeA8(width: int, height: int) -> skia.ImageInfo

Creates ImageInfo from integral dimensions width and height, kAlpha_8_ColorType, kPremul_AlphaType, with ColorSpace set to nullptr.

width:

pixel column count; must be zero or greater

height:

pixel row count; must be zero or greater
MakeA8(dimensions: skia.ISize) -> skia.ImageInfo

Creates ImageInfo from integral dimensions, kAlpha_8_ColorType, kPremul_AlphaType, with ColorSpace set to nullptr.

dimensions:

pixel row and column count; must be zero or greater

static ImageInfo.MakeN32(width: int, height: int, at: skia.AlphaType, cs: skia.ColorSpace = None) → skia.ImageInfo

Creates ImageInfo from integral dimensions width and height, kN32_ColorType, AlphaType at, and optionally ColorSpace cs.

kN32_ColorType will equal either kBGRA_8888_ColorType or kRGBA_8888_ColorType, whichever is optimal.

If ColorSpace cs is nullptr and ImageInfo is part of drawing source: ColorSpace defaults to sRGB, mapping into Surface ColorSpace.

Parameters are not validated to see if their values are legal, or that the combination is supported.

Parameters:

width (int) – pixel column count; must be zero or greater
height (int) – pixel row count; must be zero or greater
cs (skia.ColorSpace) – range of colors; may be nullptr

Returns:

created ImageInfo

static ImageInfo.MakeN32Premul(*args, **kwargs)

Overloaded function.

MakeN32Premul(width: int, height: int, cs: skia.ColorSpace = None) -> skia.ImageInfo

Creates ImageInfo from integral dimensions width and height, kN32_ColorType, kPremul_AlphaType, with optional ColorSpace.

If ColorSpace cs is nullptr and ImageInfo is part of drawing source: ColorSpace defaults to sRGB, mapping into Surface ColorSpace.

Parameters are not validated to see if their values are legal, or that the combination is supported.

width:

pixel column count; must be zero or greater

height:

pixel row count; must be zero or greater

cs:

range of colors; may be nullptr

return:

created ImageInfo
MakeN32Premul(dimensions: skia.ISize, cs: skia.ColorSpace = None) -> skia.ImageInfo

Creates ImageInfo from integral dimensions width and height, kN32_ColorType, kPremul_AlphaType, with optional ColorSpace.

If ColorSpace cs is nullptr and ImageInfo is part of drawing source: ColorSpace defaults to sRGB, mapping into Surface ColorSpace.

Parameters are not validated to see if their values are legal, or that the combination is supported.

dimensions:

width and height, each must be zero or greater

cs:

range of colors; may be nullptr

return:

created ImageInfo

static ImageInfo.MakeS32(width: int, height: int, at: skia.AlphaType) → skia.ImageInfo

Creates ImageInfo from integral dimensions width and height, kN32_ColorType, AlphaType at, with sRGB ColorSpace.

Parameters are not validated to see if their values are legal, or that the combination is supported.

Parameters:

width (int) – pixel column count; must be zero or greater
height (int) – pixel row count; must be zero or greater

Returns:

created ImageInfo

static ImageInfo.MakeUnknown(*args, **kwargs)

Overloaded function.

MakeUnknown(width: int, height: int) -> skia.ImageInfo

Creates ImageInfo from integral dimensions width and height, kUnknown_ColorType, kUnknown_AlphaType, with ColorSpace set to nullptr.

Returned ImageInfo as part of source does not draw, and as part of destination can not be drawn to.

width:

pixel column count; must be zero or greater

height:

pixel row count; must be zero or greater

return:

created ImageInfo
MakeUnknown() -> skia.ImageInfo

Creates ImageInfo from integral dimensions width and height set to zero, kUnknown_ColorType, kUnknown_AlphaType, with ColorSpace set to nullptr.

Returned ImageInfo as part of source does not draw, and as part of destination can not be drawn to.

return:

created ImageInfo

ImageInfo.__init__(self: skia.ImageInfo) → None: Creates an empty ImageInfo with kUnknown_ColorType, kUnknown_AlphaType, a width and height of zero, and no ColorSpace.

ImageInfo.alphaType(self: skia.ImageInfo) → skia.AlphaType

ImageInfo.bounds(self: skia.ImageInfo) → skia.IRect

Returns IRect (0, 0, width(), height()).

Returns:: integral rectangle from origin to width() and height()

ImageInfo.bytesPerPixel(self: skia.ImageInfo) → int

Returns number of bytes per pixel required by ColorType.

Returns zero if colorType() is kUnknown_ColorType.

Returns:: bytes in pixel

ImageInfo.colorInfo(self: skia.ImageInfo) → skia.ColorInfo: Returns the dimensionless ColorInfo that represents the same color type, alpha type, and color space as this ImageInfo.

ImageInfo.colorSpace(self: skia.ImageInfo) → skia.ColorSpace

Returns ColorSpace, the range of colors.

The reference count of ColorSpace is unchanged. The returned ColorSpace is immutable.

Returns:: ColorSpace, or nullptr

ImageInfo.colorType(self: skia.ImageInfo) → skia.ColorType

ImageInfo.computeByteSize(self: skia.ImageInfo, rowBytes: int) → int

Returns storage required by pixel array, given ImageInfo dimensions, ColorType, and rowBytes.

rowBytes is assumed to be at least as large as minRowBytes().

Returns zero if height is zero. Returns SIZE_MAX if answer exceeds the range of size_t.

Parameters:: rowBytes (int) – size of pixel row or larger
Returns:: memory required by pixel buffer

ImageInfo.computeMinByteSize(self: skia.ImageInfo) → int

Returns storage required by pixel array, given ImageInfo dimensions, and ColorType.

Uses minRowBytes() to compute bytes for pixel row.

Returns zero if height is zero. Returns SIZE_MAX if answer exceeds the range of size_t.

Returns:: least memory required by pixel buffer

ImageInfo.computeOffset(self: skia.ImageInfo, x: int, y: int, rowBytes: int) → int

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:

x (int) – column index, zero or greater, and less than width()
y (int) – row index, zero or greater, and less than height()
rowBytes (int) – size of pixel row or larger

Returns:

offset within pixel array

ImageInfo.dimensions(self: skia.ImageInfo) → skia.ISize

Returns ISize (width(), height()).

Returns:: integral size of width() and height()

ImageInfo.gammaCloseToSRGB(self: skia.ImageInfo) → bool

Returns true if associated ColorSpace is not nullptr, and ColorSpace gamma is approximately the same as sRGB.

Returns:: true if ColorSpace gamma is approximately the same as sRGB

ImageInfo.height(self: skia.ImageInfo) → int

Returns pixel row count.

Returns:: pixel height

ImageInfo.isEmpty(self: skia.ImageInfo) → bool

Returns if ImageInfo describes an empty area of pixels by checking if either width or height is zero or smaller.

Returns:: true if either dimension is zero or smaller

ImageInfo.isOpaque(self: skia.ImageInfo) → bool

Returns true if AlphaType is set to hint that all pixels are opaque; their alpha value is implicitly or explicitly 1.0.

If true, and all pixels are not opaque, Skia may draw incorrectly.

Does not check if ColorType allows alpha, or if any pixel value has transparency.

Returns:: true if AlphaType is kOpaque_AlphaType

ImageInfo.makeAlphaType(self: skia.ImageInfo, newAlphaType: skia.AlphaType) → skia.ImageInfo

Creates ImageInfo with same ColorType, ColorSpace, width, and height, with AlphaType set to newAlphaType.

Created ImageInfo contains newAlphaType even if it is incompatible with ColorType, in which case AlphaType in ImageInfo is ignored.

Parameters:: newAlphaType (skia.AlphaType) – new alpha type
Returns:: created ImageInfo

ImageInfo.makeColorSpace(self: skia.ImageInfo, cs: skia.ColorSpace) → skia.ImageInfo

Creates ImageInfo with same AlphaType, ColorType, width, and height, with ColorSpace set to cs.

Parameters:: cs (skia.ColorSpace) – range of colors; may be nullptr
Returns:: created ImageInfo

ImageInfo.makeColorType(self: skia.ImageInfo, newColorType: skia.ColorType) → skia.ImageInfo

Creates ImageInfo with same AlphaType, ColorSpace, width, and height, with ColorType set to newColorType.

Parameters:: newColorType (skia.ColorType) – new color type
Returns:: created ImageInfo

ImageInfo.makeDimensions(self: skia.ImageInfo, newSize: skia.ISize) → skia.ImageInfo

Creates ImageInfo with the same ColorType, ColorSpace, and AlphaType, with dimensions set to newDimensions.

Parameters:: newSize (skia.ISize) – pixel column and row count; must be zero or greater
Returns:: created ImageInfo

ImageInfo.makeWH(self: skia.ImageInfo, newWidth: int, newHeight: int) → skia.ImageInfo

Creates ImageInfo with the same ColorType, ColorSpace, and AlphaType, with dimensions set to width and height.

Parameters:

newWidth (int) – pixel column count; must be zero or greater
newHeight (int) – pixel row count; must be zero or greater

Returns:

created ImageInfo

ImageInfo.minRowBytes(self: skia.ImageInfo) → int

Returns minimum bytes per row, computed from pixel width() and ColorType, which specifies bytesPerPixel().

Bitmap maximum value for row bytes must fit in 31 bits.

Returns:: width() times bytesPerPixel() as signed 32-bit integer

ImageInfo.minRowBytes64(self: skia.ImageInfo) → int

Returns minimum bytes per row, computed from pixel width() and ColorType, which specifies bytesPerPixel().

Bitmap maximum value for row bytes must fit in 31 bits.

Returns:: width() times bytesPerPixel() as unsigned 64-bit integer

ImageInfo.refColorSpace(self: skia.ImageInfo) → skia.ColorSpace

Returns smart pointer to ColorSpace, the range of colors.

The smart pointer tracks the number of objects sharing this ColorSpace reference so the memory is released when the owners destruct.

The returned ColorSpace is immutable.

Returns:: ColorSpace wrapped in a smart pointer

ImageInfo.reset(self: skia.ImageInfo) → None: Creates an empty ImageInfo with kUnknown_ColorType, kUnknown_AlphaType, a width and height of zero, and no ColorSpace.

ImageInfo.shiftPerPixel(self: skia.ImageInfo) → int

Returns bit shift converting row bytes to row pixels.

Returns zero for skia.ColorType.kUnknown_ColorType.

Returns:: one of: 0, 1, 2, 3; left shift to convert pixels to bytes

ImageInfo.validRowBytes(self: skia.ImageInfo, rowBytes: int) → bool

Returns true if rowBytes is valid for this ImageInfo.

Parameters:: rowBytes (int) – size of pixel row including padding
Returns:: true if rowBytes is large enough to contain pixel row and is properly aligned

ImageInfo.width(self: skia.ImageInfo) → int

Returns pixel count in each row.

Returns:: pixel width