SkBitmap Reference

Bitmap

Class SkBitmap

Bitmap describes a two-dimensional raster pixel array. Bitmap is built on Image Info, containing integer width and height, Color Type and Alpha Type describing the pixel format, and Color Space describing the range of colors. Bitmap points to Pixel Ref, which describes the physical array of pixels. Image Info bounds may be located anywhere fully inside Pixel Ref bounds.

Bitmap can be drawn using Canvas. Bitmap can be a drawing destination for Canvas draw member functions. Bitmap flexibility as a pixel container limits some optimizations available to the target platform.

If pixel array is primarily read-only, use Image for better performance. If pixel array is primarily written to, use Surface for better performance.

Declaring SkBitmap const prevents altering Image Info: the Bitmap height, width, and so on cannot change. It does not affect Pixel Ref: a caller may write its pixels. Declaring SkBitmap const affects Bitmap configuration, not its contents.

Bitmap is not thread safe. Each thread must have its own copy of Bitmap fields, although threads may share the underlying pixel array.

Row Bytes

Bitmap pixels may be contiguous, or may have a gap at the end of each row. Row Bytes is the interval from one row to the next. Row Bytes may be specified; sometimes passing zero will compute the Row Bytes from the row width and the number of bytes in a pixel. Row Bytes may be larger than the row requires. This is useful to position one or more Bitmaps within a shared pixel array.

Overview

Related Function

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

Constant

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

Class

SkBitmap uses C++ classes to declare the public data structures and interfaces.

Constructor

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

Operator

SkBitmap operators inline class member functions with arithmetic equivalents.

Member Function

SkBitmap member functions read and modify the structure properties.

Class SkBitmap::Allocator

Member_Function

SkBitmap member functions read and modify the structure properties.

Abstract subclass of HeapAllocator.

allocPixelRef

Allocates the pixel memory for the bitmap, given its dimensions and Color Type. Returns true on success, where success means either setPixels or setPixelRef was called.

Parameters

Return Value

true if Pixel Ref was allocated

See Also

HeapAllocator


Class SkBitmap::HeapAllocator

Member_Function

SkBitmap member functions read and modify the structure properties.

Subclass of SkBitmap::Allocator that returns a Pixel Ref that allocates its pixel memory from the heap. This is the default SkBitmap::Allocator invoked by allocPixels.

allocPixelRef

Allocates the pixel memory for the bitmap, given its dimensions and Color Type. Returns true on success, where success means either setPixels or setPixelRef was called.

Parameters

Return Value

true if pixels are allocated

Example

Example Output

#Volatile
pixel address = (nil)
pixel address = 0x560ddd0ac670

See Also

SkBitmap::Allocator tryAllocPixels[2][3][4]


SkBitmap

Creates an empty Bitmap without pixels, with kUnknown_SkColorType, kUnknown_SkAlphaType, and with a width and height of zero. Pixel Ref origin is set to (0, 0). Bitmap is not volatile.

Use setInfo to associate SkColorType, SkAlphaType, width, and height after Bitmap has been created.

Return Value

empty Bitmap

Example

Example Output

width:  0  height:  0  color: kUnknown_SkColorType  alpha: kUnknown_SkAlphaType
width: 25  height: 35  color: kRGBA_8888_SkColorType  alpha: kOpaque_SkAlphaType

See Also

setInfo


SkBitmap

Copies settings from src to returned Bitmap. Shares pixels if src has pixels allocated, so both bitmaps reference the same pixels.

Parameters

Return Value

copy of src

Example

Example Output

original has pixels before copy: true
original has pixels after copy: true
copy has pixels: true

See Also

setInfo setPixelRef setPixels swap


SkBitmap

Copies settings from src to returned Bitmap. Moves ownership of src pixels to Bitmap.

Parameters

Return Value

copy of src

Example

Example Output

original has pixels before move: true
original has pixels after move: false
copy has pixels: true

See Also

setInfo setPixelRef setPixels swap


~SkBitmap

Decrements Pixel Ref reference count, if Pixel Ref is not nullptr.

See Also

Pixel Ref


operator=

Copies settings from src to returned Bitmap. Shares pixels if src has pixels allocated, so both bitmaps reference the same pixels.

Parameters

Return Value

copy of src

Example

Example Output

original has pixels before copy: true
original has pixels after copy: true
copy has pixels: true

See Also

setInfo setPixelRef setPixels swap


operator=

Copies settings from src to returned Bitmap. Moves ownership of src pixels to Bitmap.

Parameters

Return Value

copy of src

Example

Example Output

original has pixels before move: true
original has pixels after move: false
copy has pixels: true

See Also

setInfo setPixelRef setPixels swap


swap

Swaps the fields of the two bitmaps.

Parameters

Example

Example Output

one width:1 height:1 colorType:kRGBA_8888_SkColorType alphaType:kOpaque_SkAlphaType
two width:2 height:2 colorType:kBGRA_8888_SkColorType alphaType:kPremul_SkAlphaType
one width:2 height:2 colorType:kBGRA_8888_SkColorType alphaType:kPremul_SkAlphaType
two width:1 height:1 colorType:kRGBA_8888_SkColorType alphaType:kOpaque_SkAlphaType

See Also

SkBitmap(SkBitmap&& src) operator=(SkBitmap&& src)


Property

pixmap

Returns a constant reference to the Pixmap holding the Bitmap pixel address, row bytes, and Image Info.

Return Value

reference to Pixmap describing this Bitmap

Example

Example Output

----------
---xx-----
--x--x----
--x-------
--xx------
--x-x---x-
-x---x--x-
-x----xx--
-xx---x---
--xxxx-xx-
----------

See Also

peekPixels installPixels[2][3] readPixels[2][3][4] writePixels[2][3]


info

Returns width, height, Alpha Type, Color Type, and Color Space.

Return Value

reference to Image Info

Example

Example Output

width: 56 height: 56 color: BGRA_8888 alpha: Opaque

See Also

Image Info


width

Returns pixel count in each row. Should be equal or less than:

rowBytes / info.bytesPerPixel.

May be less than pixelRef.width. Will not exceed pixelRef.width less pixelRefOrigin.fX.

Return Value

pixel width in Image Info

Example

Example Output

bitmap width: 16  info width: 16

See Also

height SkPixelRef::width() SkImageInfo::width()


height

Returns pixel row count.

Maybe be less than pixelRef.height. Will not exceed pixelRef.height less pixelRefOrigin.fY.

Return Value

pixel height in Image Info

Example

Example Output

bitmap height: 32  info height: 32

See Also

width SkPixelRef::height() SkImageInfo::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 in Image Info

Example

Example Output

color type: kAlpha_8_SkColorType

See Also

alphaType SkImageInfo::colorType


alphaType

Returns Alpha Type, one of: kUnknown_SkAlphaType, kOpaque_SkAlphaType, kPremul_SkAlphaType, kUnpremul_SkAlphaType.

Return Value

Alpha Type in Image Info

Example

Example Output

alpha type: kPremul_SkAlphaType

See Also

colorType SkImageInfo::alphaType


colorSpace

Returns Color Space, the range of colors, associated with Image Info. The reference count of Color Space is unchanged. The returned Color Space is immutable.

Return Value

Color Space in Image Info, or nullptr

Example

Example Output

gammaCloseToSRGB: false  gammaIsLinear: true  isSRGB: false

See Also

Color Space SkImageInfo::colorSpace


refColorSpace

Returns smart pointer to Color Space, the range of colors, associated with Image Info. 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 in Image Info wrapped in a smart pointer

Example

Example Output

gammaCloseToSRGB: false  gammaIsLinear: true  isSRGB: false

See Also

Color Space SkImageInfo::colorSpace


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

rowBytes rowBytesAsPixels width shiftPerPixel SkImageInfo::bytesPerPixel


rowBytesAsPixels

Returns number of pixels that fit on row. Should be greater than or equal to width.

Return Value

maximum pixels per row

Example

Example Output

rowBytes: 4 rowBytesAsPixels: 1
rowBytes: 5 rowBytesAsPixels: 1
rowBytes: 6 rowBytesAsPixels: 1
rowBytes: 7 rowBytesAsPixels: 1
rowBytes: 8 rowBytesAsPixels: 2

See Also

rowBytes shiftPerPixel width 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

rowBytes rowBytesAsPixels width bytesPerPixel


empty

Returns true if either width or height are zero.

Does not check if Pixel Ref is nullptr; call drawsNothing to check width, height, and Pixel Ref.

Return Value

true if dimensions do not enclose area

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

height width drawsNothing


isNull

Returns true if Pixel Ref is nullptr.

Does not check if width or height are zero; call drawsNothing to check width, height, and Pixel Ref.

Return Value

true if no Pixel Ref is associated

Example

Example Output

empty bitmap does not have pixels
bitmap with dimensions does not have pixels
allocated bitmap does have pixels

See Also

empty drawsNothing pixelRef


drawsNothing

Returns true if width or height are zero, or if Pixel Ref is nullptr. If true, Bitmap has no effect when drawn or drawn into.

Return Value

true if drawing has no effect

Example

Example Output

empty:true  isNull:true  drawsNothing:true
empty:true  isNull:false drawsNothing:true
empty:false isNull:true  drawsNothing:true
empty:false isNull:false drawsNothing:false

See Also

empty isNull pixelRef


rowBytes

Returns row bytes, the interval from one pixel row to the next. Row bytes is at least as large aswidth * info.bytesPerPixel.

Returns zero if colorType is kUnknown_SkColorType, or if row bytes supplied to setInfo is not large enough to hold a row of pixels.

Return Value

byte length of pixel row

Example

Example Output

setInfo returned:false rowBytes:0
setInfo returned:true  rowBytes:8

See Also

info setInfo SkImageInfo::minRowBytes


setAlphaType

Sets Alpha Type, if alphaType is compatible with Color Type. Returns true unless alphaType is kUnknown_SkAlphaType and current Alpha Type is not kUnknown_SkAlphaType.

Returns true if Color Type is kUnknown_SkColorType. alphaType is ignored, and Alpha Type remains kUnknown_SkAlphaType.

Returns true if Color Type is kRGB_565_SkColorType or kGray_8_SkColorType. alphaType is ignored, and Alpha Type remains kOpaque_SkAlphaType.

If Color Type is kARGB_4444_SkColorType, kRGBA_8888_SkColorType, kBGRA_8888_SkColorType, or kRGBA_F16_SkColorType: returns true unless alphaType is kUnknown_SkAlphaType and Alpha Type is not kUnknown_SkAlphaType. If Alpha Type is kUnknown_SkAlphaType, alphaType is ignored.

If Color Type is kAlpha_8_SkColorType, returns true unless alphaType is kUnknown_SkAlphaType and Alpha Type is not kUnknown_SkAlphaType. If Alpha Type is kUnknown_SkAlphaType, alphaType is ignored. If alphaType is kUnpremul_SkAlphaType, it is treated as kPremul_SkAlphaType.

This changes Alpha Type in Pixel Ref; all bitmaps sharing Pixel Ref are affected.

Parameters

Return Value

true if Alpha Type is set

Example

See Also

Alpha Type Color Type Image Info setInfo


getPixels

Returns pixel address, the base address corresponding to the pixel origin.

Return Value

pixel address

Example

Example Output

bitmap.getColor(0, 1) == 0x00000000
bitmap.getColor(0, 0) == 0xFFFFFFFF

See Also

isNull drawsNothing


computeByteSize

Returns minimum memory required for pixel storage. Does not include unused memory on last row when rowBytesAsPixels exceeds width. Returns zero if result does not fit in size_t. Returns zero if height or width is 0. Returns height times rowBytes if colorType is kUnknown_SkColorType.

Return Value

size in bytes of image buffer

Example

Example Output

width:       1 height:       1 computeByteSize:             4
width:       1 height:    1000 computeByteSize:          4999
width:       1 height: 1000000 computeByteSize:       4999999
width:    1000 height:       1 computeByteSize:          4000
width:    1000 height:    1000 computeByteSize:       4999000
width:    1000 height: 1000000 computeByteSize:    4999999000
width: 1000000 height:       1 computeByteSize:       4000000
width: 1000000 height:    1000 computeByteSize:    4999000000
width: 1000000 height: 1000000 computeByteSize: 4999999000000

See Also

SkImageInfo::computeByteSize


isImmutable

Returns true if pixels can not change.

Most immutable Bitmap checks trigger an assert only on debug builds.

Return Value

true if pixels are immutable

Example

Example Output

original is immutable
copy is immutable

See Also

setImmutable SkPixelRef::isImmutable SkImage


setImmutable

Sets internal flag to mark Bitmap as immutable. Once set, pixels can not change. Any other bitmap sharing the same Pixel Ref are also marked as immutable. Once Pixel Ref is marked immutable, the setting cannot be cleared.

Writing to immutable Bitmap pixels triggers an assert on debug builds.

Example

See Also

isImmutable SkPixelRef::setImmutable SkImage


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 Image Info Alpha Type is kOpaque_SkAlphaType

Example

Example Output

isOpaque: false
isOpaque: false
isOpaque: true
isOpaque: true

See Also

ComputeIsOpaque SkImageInfo::isOpaque


isVolatile

Provides a hint to caller that pixels should not be cached. Only true if setIsVolatile has been called to mark as volatile.

Volatile state is not shared by other bitmaps sharing the same Pixel Ref.

Return Value

true if marked volatile

Example

Example Output

original is volatile
copy is not volatile

See Also

setIsVolatile


setIsVolatile

Sets if pixels should be read from Pixel Ref on every access. Bitmaps are not volatile by default; a GPU back end may upload pixel values expecting them to be accessed repeatedly. Marking temporary Bitmaps as volatile provides a hint to Device that the Bitmap pixels should not be cached. This can improve performance by avoiding overhead and reducing resource consumption on Device.

Parameters

Example

See Also

isVolatile


reset

Resets to its initial state; all fields are set to zero, as if Bitmap had been initialized by SkBitmap().

Sets width, height, row bytes to zero; pixel address to nullptr; SkColorType to kUnknown_SkColorType; and SkAlphaType to kUnknown_SkAlphaType.

If Pixel Ref is allocated, its reference count is decreased by one, releasing its memory if Bitmap is the sole owner.

Example

Example Output

width:1 height:1 isNull:false
width:0 height:0 isNull:true

See Also

SkBitmap() SkAlphaType SkColorType


ComputeIsOpaque

Returns true if all pixels are opaque. Color Type determines how pixels are encoded, and whether pixel describes Alpha. Returns true for Color Types without alpha in each pixel; for other Color Types, returns true if all pixels have alpha values equivalent to 1.0 or greater.

For Color Types kRGB_565_SkColorType or kGray_8_SkColorType: always returns true. For Color Types kAlpha_8_SkColorType, kBGRA_8888_SkColorType, kRGBA_8888_SkColorType: returns true if all pixel Alpha values are 255. For Color Type kARGB_4444_SkColorType: returns true if all pixel Alpha values are 15. For kRGBA_F16_SkColorType: returns true if all pixel Alpha values are 1.0 or greater.

Returns false for kUnknown_SkColorType.

Parameters

Return Value

true if all pixels have opaque values or Color Type is opaque

Example

Example Output

computeIsOpaque: false
computeIsOpaque: true
computeIsOpaque: false
computeIsOpaque: true

See Also

isOpaque Color Type Alpha


getBounds

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

Parameters

Example

See Also

bounds


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

Parameters

Example

See Also

bounds


bounds

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

Return Value

integral rectangle from origin to width and height

Example

See Also

getBounds[2]


dimensions

Returns ISize { width, height }.

Return Value

integral size of width and height

Example

See Also

height width


getSubset

Returns the bounds of this bitmap, offset by its Pixel Ref origin.

Return Value

bounds within Pixel Ref bounds

Example

Example Output

source: 0, 0, 512, 512
subset: 100, 100, 412, 412

See Also

extractSubset getBounds[2]


setInfo

Sets width, height, Alpha Type, Color Type, Color Space, and optional rowBytes. Frees pixels, and returns true if successful.

imageInfo.alphaType may be altered to a value permitted by imageInfo.colorSpace. If imageInfo.colorType is kUnknown_SkColorType, imageInfo.alphaType is set to kUnknown_SkAlphaType. If imageInfo.colorType is kAlpha_8_SkColorType and imageInfo.alphaType is kUnpremul_SkAlphaType, imageInfo.alphaType is replaced by kPremul_SkAlphaType. If imageInfo.colorType is kRGB_565_SkColorType or kGray_8_SkColorType, imageInfo.alphaType is set to kOpaque_SkAlphaType. If imageInfo.colorType is kARGB_4444_SkColorType, kRGBA_8888_SkColorType, kBGRA_8888_SkColorType, or kRGBA_F16_SkColorType: imageInfo.alphaType remains unchanged.

rowBytes must equal or exceed imageInfo.minRowBytes. If imageInfo.colorSpace is kUnknown_SkColorType, rowBytes is ignored and treated as zero; for all other Color Space values, rowBytes of zero is treated as imageInfo.minRowBytes.

Calls reset and returns false if:

Parameters

Return Value

true if Image Info set successfully

Example

See Also

Alpha Type Color Type Color Space height rowBytes width


Enum SkBitmap::AllocFlags

AllocFlags provides the option to zero pixel memory when allocated.

Constants

See Also

tryAllocPixelsFlags allocPixelsFlags erase eraseColor

Allocate

tryAllocPixelsFlags

Sets Image Info to info following the rules in setInfo and allocates pixel memory. If flags is kZeroPixels AllocFlag, memory is zeroed.

Returns false and calls reset if Image Info could not be set, or memory could not be allocated, or memory could not optionally be zeroed.

On most platforms, allocating pixel memory may succeed even though there is not sufficient memory to hold pixels; allocation does not take place until the pixels are written to. The actual behavior depends on the platform implementation of malloc(), if flags is zero, and calloc(), if flags is kZeroPixels AllocFlag.

flags set to kZeroPixels AllocFlag offers equal or better performance than subsequently calling eraseColor with SK ColorTRANSPARENT.

Parameters

Return Value

true if pixels allocation is successful

Example

Example Output

bitmap allocation succeeded!

See Also

allocPixelsFlags tryAllocPixels[2][3][4] SkMallocPixelRef::MakeZeroed


allocPixelsFlags

Sets Image Info to info following the rules in setInfo and allocates pixel memory. If flags is kZeroPixels AllocFlag, memory is zeroed.

Aborts execution if Image Info could not be set, or memory could not be allocated, or memory could not optionally be zeroed. Abort steps may be provided by the user at compile time by defining SK_ABORT.

On most platforms, allocating pixel memory may succeed even though there is not sufficient memory to hold pixels; allocation does not take place until the pixels are written to. The actual behavior depends on the platform implementation of malloc(), if flags is zero, and calloc(), if flags is kZeroPixels AllocFlag.

flags set to kZeroPixels AllocFlag offers equal or better performance than subsequently calling eraseColor with SK ColorTRANSPARENT.

Parameters

Example

See Also

tryAllocPixelsFlags allocPixels[2][3][4] SkMallocPixelRef::MakeZeroed


tryAllocPixels

Sets Image Info to info following the rules in setInfo and allocates pixel memory. rowBytes must equal or exceed info.width times info.bytesPerPixel, or equal zero. Pass in zero for rowBytes to compute the minimum valid value.

Returns false and calls reset if Image Info could not be set, or memory could not be allocated.

On most platforms, allocating pixel memory may succeed even though there is not sufficient memory to hold pixels; allocation does not take place until the pixels are written to. The actual behavior depends on the platform implementation of malloc().

Parameters

Return Value

true if pixel storage is allocated

Example

See Also

tryAllocPixelsFlags allocPixels[2][3][4] SkMallocPixelRef::MakeAllocate


allocPixels

Sets Image Info to info following the rules in setInfo and allocates pixel memory. rowBytes must equal or exceed info.width times info.bytesPerPixel, or equal zero. Pass in zero for rowBytes to compute the minimum valid value.

Aborts execution if Image Info could not be set, or memory could not be allocated. Abort steps may be provided by the user at compile time by defining SK_ABORT.

On most platforms, allocating pixel memory may succeed even though there is not sufficient memory to hold pixels; allocation does not take place until the pixels are written to. The actual behavior depends on the platform implementation of malloc().

Parameters

Example

See Also

tryAllocPixels[2][3][4] allocPixelsFlags SkMallocPixelRef::MakeAllocate


Sets Image Info to info following the rules in setInfo and allocates pixel memory.

Returns false and calls reset if Image Info could not be set, or memory could not be allocated.

On most platforms, allocating pixel memory may succeed even though there is not sufficient memory to hold pixels; allocation does not take place until the pixels are written to. The actual behavior depends on the platform implementation of malloc().

Parameters

Return Value

true if pixel storage is allocated

Example

See Also

tryAllocPixelsFlags allocPixels[2][3][4] SkMallocPixelRef::MakeAllocate


Sets Image Info to info following the rules in setInfo and allocates pixel memory.

Aborts execution if Image Info could not be set, or memory could not be allocated. Abort steps may be provided by the user at compile time by defining SK_ABORT.

On most platforms, allocating pixel memory may succeed even though there is not sufficient memory to hold pixels; allocation does not take place until the pixels are written to. The actual behavior depends on the platform implementation of malloc().

Parameters

Example

See Also

tryAllocPixels[2][3][4] allocPixelsFlags SkMallocPixelRef::MakeAllocate


tryAllocN32Pixels

Sets Image Info to width, height, and Native_Color_Type; and allocates pixel memory. If isOpaque is true, sets Image Info to kOpaque_SkAlphaType; otherwise, sets to kPremul_SkAlphaType.

Calls reset and returns false if width exceeds 29 bits or is negative, or height is negative.

Returns false if allocation fails.

Use to create Bitmap that matches SkPMColor, the native pixel arrangement on the platform. Bitmap drawn to output device skips converting its pixel format.

Parameters

Return Value

true if pixel storage is allocated

Example

See Also

tryAllocPixels[2][3][4] allocN32Pixels SkMallocPixelRef::MakeAllocate


allocN32Pixels

Sets Image Info to width, height, and the Native_Color_Type; and allocates pixel memory. If isOpaque is true, sets Image Info to kPremul_SkAlphaType; otherwise, sets to kOpaque_SkAlphaType.

Aborts if width exceeds 29 bits or is negative, or height is negative, or allocation fails. Abort steps may be provided by the user at compile time by defining SK_ABORT.

Use to create Bitmap that matches SkPMColor, the native pixel arrangement on the platform. Bitmap drawn to output device skips converting its pixel format.

Parameters

Example

See Also

allocPixels[2][3][4] tryAllocN32Pixels SkMallocPixelRef::MakeAllocate


installPixels

Sets Image Info to info following the rules in setInfo, and creates Pixel Ref containing pixels and rowBytes. releaseProc, if not nullptr, is called immediately on failure or when pixels are no longer referenced. context may be nullptr.

If Image Info could not be set, or rowBytes is less than info.minRowBytes: calls releaseProc if present, calls reset, and returns false.

Otherwise, if pixels equals nullptr: sets Image Info, calls releaseProc if present, returns true.

If Image Info is set, pixels is not nullptr, and releaseProc is not nullptr: when pixels are no longer referenced, calls releaseProc with pixels and context as parameters.

Parameters

Return Value

true if Image Info is set to info

Example

Example Output

before installPixels
releaseProc called
install not successful

See Also

allocPixels[2][3][4]


Sets Image Info to info following the rules in setInfo, and creates Pixel Ref containing pixels and rowBytes.

If Image Info could not be set, or rowBytes is less than info.minRowBytes: calls reset, and returns false.

Otherwise, if pixels equals nullptr: sets Image Info, returns true.

Caller must ensure that pixels are valid for the lifetime of Bitmap and Pixel Ref.

Parameters

Return Value

true if Image Info is set to info

Example

See Also

allocPixels[2][3][4]


Sets Image Info to pixmap.info following the rules in setInfo, and creates Pixel Ref containing pixmap.addr() and pixmap.rowBytes.

If Image Info could not be set, or pixmap.rowBytes is less than SkImageInfo::minRowBytes: calls reset, and returns false.

Otherwise, if pixmap.addr() equals nullptr: sets Image Info, returns true.

Caller must ensure that pixmap is valid for the lifetime of Bitmap and Pixel Ref.

Parameters

Return Value

true if Image Info was set to pixmap.info

Example

See Also

allocPixels[2][3][4]


installMaskPixels

Deprecated.

soon


Pixels

setPixels

Replaces Pixel Ref with pixels, preserving Image Info and rowBytes. Sets Pixel Ref origin to (0, 0).

If pixels is nullptr, or if info.colorType equals kUnknown_SkColorType; release reference to Pixel Ref, and set Pixel Ref to nullptr.

Caller is responsible for handling ownership pixel memory for the lifetime of Bitmap and Pixel Ref.

Parameters

Example

See Also

installPixels[2][3] allocPixels[2][3][4]


Allocates pixel memory with HeapAllocator, and replaces existing Pixel Ref. The allocation size is determined by Image Info width, height, and Color Type.

Returns false if info.colorType is kUnknown_SkColorType, or allocation fails.

Return Value

true if the allocation succeeds

Example

See Also

allocPixels[2][3][4] installPixels[2][3] setPixels


Allocates pixel memory with HeapAllocator, and replaces existing Pixel Ref. The allocation size is determined by Image Info width, height, and Color Type.

Aborts if info.colorType is kUnknown_SkColorType, or allocation fails. Abort steps may be provided by the user at compile time by defining SK_ABORT.

Example

See Also

tryAllocPixels[2][3][4] installPixels[2][3] setPixels


Allocates pixel memory with allocator, and replaces existing Pixel Ref. The allocation size is determined by Image Info width, height, and Color Type. If allocator is nullptr, use HeapAllocator instead.

Returns false if Allocator::allocPixelRef return false.

Parameters

Return Value

true if custom allocator reports success

Example

See Also

allocPixels[2][3][4] Allocator Pixel Ref


Allocates pixel memory with allocator, and replaces existing Pixel Ref. The allocation size is determined by Image Info width, height, and Color Type. If allocator is nullptr, use HeapAllocator instead.

Aborts if Allocator::allocPixelRef return false. Abort steps may be provided by the user at compile time by defining SK_ABORT.

Parameters

Example

See Also

allocPixels[2][3][4] Allocator Pixel Ref


pixelRef

Returns Pixel Ref, which contains: pixel base address; its dimensions; and rowBytes, the interval from one row to the next. Does not change Pixel Ref reference count. Pixel Ref may be shared by multiple bitmaps. If Pixel Ref has not been set, returns nullptr.

Return Value

Pixel Ref, or nullptr

Example

See Also

getPixels getAddr


pixelRefOrigin

Returns origin of pixels within Pixel Ref. Bitmap bounds is always contained by Pixel Ref bounds, which may be the same size or larger. Multiple Bitmaps can share the same Pixel Ref, where each Bitmap has different bounds.

The returned origin added to Bitmap dimensions equals or is smaller than the Pixel Ref dimensions.

Returns (0, 0) if Pixel Ref is nullptr.

Return Value

pixel origin within Pixel Ref

Example

Example Output

source origin: 0, 0
subset origin: 32, 64

See Also

SkPixelRef getSubset setPixelRef


Set

setPixelRef

Replaces pixelRef and origin in Bitmap. dx and dy specify the offset within the Pixel Ref pixels for the top-left corner of the bitmap.

Asserts in debug builds if dx or dy are out of range. Pins dx and dy to legal range in release builds.

The caller is responsible for ensuring that the pixels match the Color Type and Alpha Type in Image Info.

Parameters

Example

See Also

setInfo


readyToDraw

Returns true if Bitmap is can be drawn.

Return Value

true if getPixels is not nullptr

Example

See Also

getPixels drawsNothing


getGenerationID

Returns a unique value corresponding to the pixels in Pixel Ref. Returns a different value after notifyPixelsChanged has been called. Returns zero if Pixel Ref is nullptr.

Determines if pixels have changed since last examined.

Return Value

unique value for pixels in Pixel Ref

Example

Example Output

#Volatile
empty id 0
alloc id 4
erase id 6

See Also

notifyPixelsChanged Pixel Ref


notifyPixelsChanged

Marks that pixels in Pixel Ref have changed. Subsequent calls to getGenerationID return a different value.

Example

See Also

getGenerationID isVolatile Pixel Ref


Draw

eraseColor

Replaces pixel values with c. All pixels contained by bounds are affected. If the colorType is kGray_8_SkColorType or k565_SkColorType, then Color Alpha is ignored; RGB is treated as opaque. If colorType is kAlpha_8_SkColorType, then RGB is ignored.

Parameters

Example

See Also

eraseARGB erase


eraseARGB

Replaces pixel values with Unpremultiplied Color built from a, r, g, and b. All pixels contained by bounds are affected. If the colorType is kGray_8_SkColorType or k565_SkColorType, then a is ignored; r, g, and b are treated as opaque. If colorType is kAlpha_8_SkColorType, then r, g, and b are ignored.

Parameters

Example

See Also

eraseColor erase


eraseRGB

Deprecated.


erase

Replaces pixel values inside area with c. If area does not intersect bounds, call has no effect.

If the colorType is kGray_8_SkColorType or k565_SkColorType, then Color Alpha is ignored; RGB is treated as opaque. If colorType is kAlpha_8_SkColorType, then RGB is ignored.

Parameters

Example

See Also

eraseColor eraseARGB eraseRGB SkCanvas::drawRect


eraseArea

Deprecated.


getColor

Returns pixel at (x, y) as Unpremultiplied Color. Returns black with Alpha if Color Type is kAlpha_8_SkColorType.

Input is not validated: out of bounds values of x or y trigger an assert() if built with SK_DEBUG defined; and returns undefined values or may crash if SK_RELEASE is defined. Fails if Color Type is kUnknown_SkColorType or pixel address is nullptr.

Color Space in Image Info is ignored. Some Color precision may be lost in the conversion to Unpremultiplied Color; original pixel data may have additional precision.

Parameters

Return Value

pixel converted to Unpremultiplied Color

Example

Example Output

Premultiplied:
(0, 0) 0x00000000 0x2a0e002a 0x55380055 0x7f7f007f
(0, 1) 0x2a000e2a 0x551c1c55 0x7f542a7f 0xaaaa38aa
(0, 2) 0x55003855 0x7f2a547f 0xaa7171aa 0xd4d48dd4
(0, 3) 0x7f007f7f 0xaa38aaaa 0xd48dd4d4 0xffffffff
Unpremultiplied:
(0, 0) 0x00000000 0x2a5500ff 0x55a800ff 0x7fff00ff
(0, 1) 0x2a0055ff 0x555454ff 0x7fa954ff 0xaaff54ff
(0, 2) 0x5500a8ff 0x7f54a9ff 0xaaaaaaff 0xd4ffaaff
(0, 3) 0x7f00ffff 0xaa54ffff 0xd4aaffff 0xffffffff

See Also

getAddr readPixels[2][3][4]


getAddr

Returns pixel address at (x, y).

Input is not validated: out of bounds values of x or y, or kUnknown_SkColorType, trigger an assert() if built with SK_DEBUG defined. Returns nullptr if Color Type is kUnknown_SkColorType, or Pixel Ref is nullptr.

Performs a lookup of pixel size; for better performance, call one of: getAddr8, getAddr16, or getAddr32.

Parameters

Return Value

generic pointer to pixel

Example

Example Output

addr interval == rowBytes

See Also

getAddr8 getAddr16 getAddr32 readPixels[2][3][4] SkPixmap::addr[2]


getAddr32

Returns address at (x, y).

Input is not validated. Triggers an assert() if built with SK_DEBUG defined and:

Parameters

Return Value

unsigned 32-bit pointer to pixel at (x, y)

Example

Example Output

addr interval == rowBytes

See Also

getAddr8 getAddr16 getAddr readPixels[2][3][4] SkPixmap::addr32[2]


getAddr16

Returns address at (x, y).

Input is not validated. Triggers an assert() if built with SK_DEBUG defined and:

Parameters

Return Value

unsigned 16-bit pointer to pixel at (x, y)

Example

Example Output

addr interval == rowBytes

See Also

getAddr8 getAddr getAddr32 readPixels[2][3][4] SkPixmap::addr16[2]


getAddr8

Returns address at (x, y).

Input is not validated. Triggers an assert() if built with SK_DEBUG defined and:

Parameters

Return Value

unsigned 8-bit pointer to pixel at (x, y)

Example

Example Output

&pixels[4][2] == bitmap.getAddr8(2, 4)

See Also

getAddr getAddr16 getAddr32 readPixels[2][3][4] SkPixmap::addr8[2]


extractSubset

Shares Pixel Ref with dst. Pixels are not copied; Bitmap and dst point to the same pixels; dst bounds are set to the intersection of subset and the original bounds.

subset may be larger than bounds. Any area outside of bounds is ignored.

Any contents of dst are discarded. isVolatile setting is copied to dst. dst is set to colorType, alphaType, and colorSpace.

Return false if:

Parameters

Return Value

true if dst is replaced by subset

Example

Example Output

bounds: 0, 0, 512, 512
subset: -100,  100,    0,  200  success; false
subset: -100,  100,  100,  200  success; true  subset: 0, 0, 100, 100
subset: -100,  100, 1000,  200  success; true  subset: 0, 0, 512, 100
subset:    0,  100,    0,  200  success; false
subset:    0,  100,  100,  200  success; true  subset: 0, 0, 100, 100
subset:    0,  100, 1000,  200  success; true  subset: 0, 0, 512, 100
subset:  100,  100,    0,  200  success; false
subset:  100,  100,  100,  200  success; false
subset:  100,  100, 1000,  200  success; true  subset: 0, 0, 412, 100
subset: 1000,  100,    0,  200  success; false
subset: 1000,  100,  100,  200  success; false
subset: 1000,  100, 1000,  200  success; false

See Also

readPixels[2][3][4] writePixels[2][3] SkCanvas::drawBitmap


readPixels

Copies Rect of pixels from Bitmap pixels to dstPixels. Copy starts at (srcX, srcY), and does not exceed Bitmap (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:

Pixels are copied only if pixel conversion is possible. If Bitmap colorType is kGray_8_SkColorType, or kAlpha_8_SkColorType; dstInfo.colorType must match. If Bitmap colorType is kGray_8_SkColorType, dstInfo.colorSpace must match. If Bitmap alphaType is kOpaque_SkAlphaType, dstInfo.alphaType must match. If Bitmap colorSpace 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) >= Bitmap width, or ifabs(srcY) >= Bitmap height.

If behavior is SkTransferFunctionBehavior::kRespect: converts source pixels to a linear space before converting to dstInfo. If behavior is SkTransferFunctionBehavior::kIgnore: source pixels are treated as if they are linear, regardless of how they are encoded.

Parameters

Return Value

true if pixels are copied to dstPixels

Example

See Also

writePixels[2][3] SkPixmap::readPixels[2][3][4][5] SkCanvas::readPixels[2][3] SkImage::readPixels[2] SkSurface::readPixels[2][3]


Copies a Rect of pixels from Bitmap to dstPixels. Copy starts at (srcX, srcY), and does not exceed Bitmap (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:

Pixels are copied only if pixel conversion is possible. If Bitmap colorType is kGray_8_SkColorType, or kAlpha_8_SkColorType; dstInfo.colorType must match. If Bitmap colorType is kGray_8_SkColorType, dstInfo.colorSpace must match. If Bitmap alphaType is kOpaque_SkAlphaType, dstInfo.alphaType must match. If Bitmap colorSpace 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) >= Bitmap width, or ifabs(srcY) >= Bitmap height.

Parameters

Return Value

true if pixels are copied to dstPixels

Example

See Also

writePixels[2][3] SkPixmap::readPixels[2][3][4][5] SkCanvas::readPixels[2][3] SkImage::readPixels[2] SkSurface::readPixels[2][3]


Copies a Rect of pixels from Bitmap to dst. Copy starts at (srcX, srcY), and does not exceed Bitmap (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:

Pixels are copied only if pixel conversion is possible. If Bitmap colorType is kGray_8_SkColorType, or kAlpha_8_SkColorType; dst Color Type must match. If Bitmap colorType is kGray_8_SkColorType, dst Color Space must match. If Bitmap alphaType is kOpaque_SkAlphaType, dst Alpha Type must match. If Bitmap colorSpace is nullptr, dst Color Space 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) >= Bitmap width, or ifabs(srcY) >= Bitmap height.

Parameters

Return Value

true if pixels are copied to dst

Example

See Also

writePixels[2][3] SkPixmap::readPixels[2][3][4][5] SkCanvas::readPixels[2][3] SkImage::readPixels[2] SkSurface::readPixels[2][3]


Copies a Rect of pixels from Bitmap to dst. Copy starts at (0, 0), and does not exceed Bitmap (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:

Pixels are copied only if pixel conversion is possible. If Bitmap colorType is kGray_8_SkColorType, or kAlpha_8_SkColorType; dst Color Type must match. If Bitmap colorType is kGray_8_SkColorType, dst Color Space must match. If Bitmap alphaType is kOpaque_SkAlphaType, dst Alpha Type must match. If Bitmap colorSpace is nullptr, dst Color Space must match. Returns false if pixel conversion is not possible.

Parameters

Return Value

true if pixels are copied to dst

Example

See Also

writePixels[2][3] SkPixmap::readPixels[2][3][4][5] SkCanvas::readPixels[2][3] SkImage::readPixels[2] SkSurface::readPixels[2][3]


writePixels

Copies a Rect of pixels from src. Copy starts at (dstX, dstY), and does not exceed (src.width, src.height).

src specifies width, height, Color Type, Alpha Type, Color Space, pixel storage, and row bytes of source. src.rowBytes specifics the gap from one source row to the next. Returns true if pixels are copied. Returns false if:

Pixels are copied only if pixel conversion is possible. If Bitmap colorType is kGray_8_SkColorType, or kAlpha_8_SkColorType; src Color Type must match. If Bitmap colorType is kGray_8_SkColorType, src Color Space must match. If Bitmap alphaType is kOpaque_SkAlphaType, src Alpha Type must match. If Bitmap colorSpace is nullptr, src Color Space must match. Returns false if pixel conversion is not possible.

dstX and dstY may be negative to copy only top or left of source. Returns false if width or height is zero or negative. Returns false ifabs(dstX) >= Bitmap width, or ifabs(dstY) >= Bitmap height.

Parameters

Return Value

true if src pixels are copied to Bitmap

Example

See Also

readPixels[2][3][4]


Copies a Rect of pixels from src. Copy starts at (0, 0), and does not exceed (src.width, src.height).

src specifies width, height, Color Type, Alpha Type, Color Space, pixel storage, and row bytes of source. src.rowBytes specifics the gap from one source row to the next. Returns true if pixels are copied. Returns false if:

Pixels are copied only if pixel conversion is possible. If Bitmap colorType is kGray_8_SkColorType, or kAlpha_8_SkColorType; src Color Type must match. If Bitmap colorType is kGray_8_SkColorType, src Color Space must match. If Bitmap alphaType is kOpaque_SkAlphaType, src Alpha Type must match. If Bitmap colorSpace is nullptr, src Color Space must match. Returns false if pixel conversion is not possible.

Parameters

Return Value

true if src pixels are copied to Bitmap

Example

See Also

readPixels[2][3][4]


Copies a Rect of pixels from src. Copy starts at (0, 0), and does not exceed (src.width, src.height).

src specifies width, height, Color Type, Alpha Type, Color Space, pixel storage, and row bytes of source. src.rowBytes specifics the gap from one source row to the next. Returns true if pixels are copied. Returns false if:

Pixels are copied only if pixel conversion is possible. If Bitmap colorType is kGray_8_SkColorType, or kAlpha_8_SkColorType; src Color Type must match. If Bitmap colorType is kGray_8_SkColorType, src Color Space must match. If Bitmap alphaType is kOpaque_SkAlphaType, src Alpha Type must match. If Bitmap colorSpace is nullptr, src Color Space must match. Returns false if pixel conversion is not possible. Returns false if width or height is zero or negative.

If behavior is SkTransferFunctionBehavior::kRespect: converts src pixels to a linear space before converting to Image Info. If behavior is SkTransferFunctionBehavior::kIgnore: src pixels are treated as if they are linear, regardless of how they are encoded.

Parameters

Return Value

true if src pixels are copied to Bitmap

Example

See Also

readPixels[2][3][4]


hasHardwareMipMap

For use by Android framework only.

Return Value

true if setHasHardwareMipMap has been called with true

See Also

setHasHardwareMipMap


setHasHardwareMipMap

For use by Android framework only.

Parameters

See Also

hasHardwareMipMap


extractAlpha

Sets dst to Alpha described by pixels. Returns false if dst cannot be written to or dst pixels cannot be allocated.

Uses HeapAllocator to reserve memory for dst Pixel Ref.

Parameters

Return Value

true if Alpha layer was constructed in dst Pixel Ref

Example

See Also

extractSubset


Sets dst to Alpha described by pixels. Returns false if dst cannot be written to or dst pixels cannot be allocated.

If paint is not nullptr and contains Mask Filter, SkMaskFilter generates Mask Alpha from Bitmap. Uses HeapAllocator to reserve memory for dst Pixel Ref. Sets offset to top-left position for dst for alignment with Bitmap; (0, 0) unless SkMaskFilter generates mask.

Parameters

Return Value

true if Alpha layer was constructed in dst Pixel Ref

Example

See Also

extractSubset


Sets dst to Alpha described by pixels. Returns false if dst cannot be written to or dst pixels cannot be allocated.

If paint is not nullptr and contains Mask Filter, SkMaskFilter generates Mask Alpha from Bitmap. allocator may reference a custom allocation class or be set to nullptr to use HeapAllocator. Sets offset to top-left position for dst for alignment with Bitmap; (0, 0) unless SkMaskFilter generates mask.

Parameters

Return Value

true if Alpha layer was constructed in dst Pixel Ref

Example

See Also

extractSubset


peekPixels

Copies Bitmap 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.

pixmap contents become invalid on any future change to Bitmap.

Parameters

Return Value

true if Bitmap has direct access to pixels

Example

Example Output

------
-xxx--
x---x-
----x-
---x--
--x---
--x---
------
--x---
--x---
------

See Also

pixmap installPixels[2][3] readPixels[2][3][4] writePixels[2][3]


Utility

validate

Asserts if internal values are illegal or inconsistent. Only available if SK_DEBUG is defined at compile time.

See Also

SkImageInfo::validate