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

Topic Description
Class Declarations embedded class members
Constants enum and enum class, and their const values
Constructors functions that construct SkBitmap
Functions global and class member functions
Operators operator overloading methods
Related Functions similar member functions grouped together

Related Function

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

Topic Description
Allocate allocates storage for pixels
Draw sets pixels to Color
Pixels read and write pixel values
Property metrics and attributes
Row Bytes interval from one row to the next
Set updates values and attributes
Utility rarely called management functions

Constant

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

Topic Description
AllocFlags zero pixel memory
kZeroPixels AllocFlag zero pixel memory

Class

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

Topic Description
Allocator abstract subclass of HeapAllocator
HeapAllocator allocates pixel memory from heap

Constructor

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

Topic Description
SkBitmap() constructs with default values
SkBitmap(SkBitmap&& src) takes ownership of pixels
SkBitmap(const SkBitmap& src) shares ownership of pixels
extractAlpha creates Bitmap containing Alpha of pixels
extractAlpha(SkBitmap* dst) const
extractAlpha(SkBitmap* dst, const SkPaint* paint, SkIPoint* offset) const
extractAlpha(SkBitmap* dst, const SkPaint* paint, Allocator* allocator, SkIPoint* offset) const
extractSubset creates Bitmap, sharing pixels if possible
reset sets to default values, releases pixel ownership
~SkBitmap() releases ownership of pixels

Operator

SkBitmap operators inline class member functions with arithmetic equivalents.

Topic Description
operator=(SkBitmap&& src) takes ownership of pixels
operator=(const SkBitmap& src) shares ownership of pixels

Member Function

SkBitmap member functions read and modify the structure properties.

Topic Description
ComputeIsOpaque returns true if all pixels are opaque
allocN32Pixels allocates compatible ARGB pixels, or aborts
allocPixels allocates pixels from Image Info, or aborts
allocPixelsFlags allocates pixels from Image Info with options, or aborts
alphaType returns Image Info Alpha Type
bounds returns width and height as Rectangle
bytesPerPixel returns number of bytes in pixel based on Color Type
colorSpace returns Image Info Color Space
colorType returns Image Info Color Type
computeByteSize returns size required for pixels
dimensions returns width and height
drawsNothing returns true if no width, no height, or no Pixel Ref
empty returns true if Image Info has zero width or height
erase writes Color to rectangle of pixels
eraseARGB writes Color to pixels
eraseColor writes Color to pixels
extractAlpha creates Bitmap containing Alpha of pixels
extractSubset creates Bitmap, sharing pixels if possible
getAddr returns readable pixel address as void pointer
getAddr16 returns readable pixel address as 16-bit pointer
getAddr32 returns readable pixel address as 32-bit pointer
getAddr8 returns readable pixel address as 8-bit pointer
getBounds returns width and height as Rectangle
getColor returns one pixel as Unpremultiplied Color
getGenerationID returns unique ID
getPixels returns address of pixels
getSubset returns bounds offset by origin
hasHardwareMipMap returns Mip Map support present; Android only
height returns pixel row count
info returns Image Info
installPixels creates Pixel Ref, with optional release function
isImmutable returns true if pixels will not change
isNull returns true if Pixel Ref is nullptr
isOpaque returns true if Image Info describes opaque pixels
isVolatile returns true if pixels should not be cached
notifyPixelsChanged marks pixels as changed, altering the unique ID
peekPixels returns Pixmap if possible
pixelRef returns Pixel Ref, or nullptr
pixelRefOrigin returns offset within Pixel Ref
pixmap returns Pixmap
readPixels copies and converts pixels
readyToDraw returns true if address of pixels is not nullptr
refColorSpace returns Image Info Color Space
reset sets to default values, releases pixel ownership
rowBytes returns interval between rows in bytes
rowBytesAsPixels returns interval between rows in pixels
setAlphaType sets Alpha Type of shared pixels
setHasHardwareMipMap sets Mip Map support present; Android only
setImmutable marks that pixels will not change
setInfo sets height, width, Color Type, and so on, releasing pixels
setIsVolatile marks if pixels should not be cached
setPixelRef sets Pixel Ref and offset
setPixels sets Pixel Ref without an offset
shiftPerPixel returns bit shift from pixels to bytes
swap exchanges Bitmap pair
tryAllocN32Pixels allocates compatible ARGB pixels if possible
tryAllocPixels allocates pixels from Image Info if possible
tryAllocPixelsFlags allocates pixels from Image Info with options if possible
validate asserts if Bitmap is invalid (debug only)
width returns pixel column count
writePixels copies and converts pixels

Class SkBitmap::Allocator

Member_Function

SkBitmap::Allocator member functions read and modify the structure properties.

Topic Description
allocPixelRef allocates pixel memory

    class Allocator : public SkRefCnt {
    public:
        virtual bool allocPixelRef(SkBitmap* bitmap) = 0;
    };

Abstract subclass of HeapAllocator.

allocPixelRef

virtual bool allocPixelRef(SkBitmap* bitmap) = 0

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

bitmap Bitmap containing Image Info as input, and Pixel Ref as output

Return Value

true if Pixel Ref was allocated

See Also

HeapAllocator


Class SkBitmap::HeapAllocator

Member_Function

SkBitmap::HeapAllocator member functions read and modify the structure properties.

Topic Description
allocPixelRef allocates pixel memory

    class HeapAllocator : public Allocator {
    public:
        bool allocPixelRef(SkBitmap* bitmap) override;
    };

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

bool allocPixelRef(SkBitmap* bitmap) override

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

bitmap Bitmap containing Image Info as input, and Pixel Ref as output

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

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

SkBitmap(const SkBitmap& src)

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

Parameters

src Bitmap to copy Image Info, and share Pixel Ref

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

SkBitmap(SkBitmap&& src)

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

Parameters

src Bitmap to copy Image Info, and reassign Pixel Ref

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

~SkBitmap()

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

See Also

Pixel Ref


operator=

SkBitmap& operator=(const SkBitmap& src)

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

Parameters

src Bitmap to copy Image Info, and share Pixel Ref

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=

SkBitmap& operator=(SkBitmap&& src)

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

Parameters

src Bitmap to copy Image Info, and reassign Pixel Ref

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

void swap(SkBitmap& other)

Swaps the fields of the two bitmaps.

Parameters

other Bitmap exchanged with original

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

Topic Description
alphaType returns Image Info Alpha Type
bounds returns width and height as Rectangle
bytesPerPixel returns number of bytes in pixel based on Color Type
colorSpace returns Image Info Color Space
colorType returns Image Info Color Type
dimensions returns width and height
drawsNothing returns true if no width, no height, or no Pixel Ref
empty returns true if Image Info has zero width or height
getAddr returns readable pixel address as void pointer
getAddr16 returns readable pixel address as 16-bit pointer
getAddr32 returns readable pixel address as 32-bit pointer
getAddr8 returns readable pixel address as 8-bit pointer
getBounds returns width and height as Rectangle
getBounds(SkRect* bounds) const
getBounds(SkIRect* bounds) const
getColor returns one pixel as Unpremultiplied Color
getPixels returns address of pixels
getSubset returns bounds offset by origin
hasHardwareMipMap returns Mip Map support present; Android only
height returns pixel row count
info returns Image Info
isImmutable returns true if pixels will not change
isNull returns true if Pixel Ref is nullptr
isOpaque returns true if Image Info describes opaque pixels
isVolatile returns true if pixels should not be cached
pixelRef returns Pixel Ref, or nullptr
pixelRefOrigin returns offset within Pixel Ref
pixmap returns Pixmap
refColorSpace returns Image Info Color Space
rowBytes returns interval between rows in bytes
rowBytesAsPixels returns interval between rows in pixels
shiftPerPixel returns bit shift from pixels to bytes
width returns pixel column count

pixmap

const SkPixmap& pixmap() const

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] writePixels[2]


info

const SkImageInfo& info() const

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

int width() const

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

int height() const

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

SkColorType colorType() const

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

SkAlphaType alphaType() const

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

SkColorSpace* colorSpace() const

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

SkColorSpace::MakeSRGBLinear creates Color Space with linear gamma and an sRGB gamut. This Color Space gamma is not close to sRGB gamma.

Example Output

gammaCloseToSRGB: false  gammaIsLinear: true  isSRGB: false

See Also

Color Space SkImageInfo::colorSpace


refColorSpace

sk sp<SkColorSpace> refColorSpace() const

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

int bytesPerPixel() const

Returns number of bytes per pixel required by Color Type. Returns zero if colorType( is kUnknown_SkColorType.

Return Value

bytes in pixel

Example

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 #### 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

int rowBytesAsPixels() const

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

int shiftPerPixel() const

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

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 #### 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

bool empty() const

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

bool isNull() const

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

bool drawsNothing() const

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

size_t rowBytes() const

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

bool setAlphaType(SkAlphaType alphaType)

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

alphaType one of: kUnknown_SkAlphaType, kOpaque_SkAlphaType, kPremul_SkAlphaType, kUnpremul_SkAlphaType

Return Value

true if Alpha Type is set

Example

kUnknown_SkAlphaType, kOpaque_SkAlphaType, kPremul_SkAlphaType, kUnpremul_SkAlphaType 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

See Also

Alpha Type Color Type Image Info setInfo


getPixels

void* getPixels() const

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

size_t computeByteSize() const

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

bool isImmutable() const

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

void 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

Triggers assert if SK_DEBUG is true, runs fine otherwise.

See Also

isImmutable SkPixelRef::setImmutable SkImage


isOpaque

bool isOpaque() const

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

isOpaque ignores whether all pixels are opaque or not.

Example Output

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

See Also

ComputeIsOpaque SkImageInfo::isOpaque


isVolatile

bool isVolatile() const

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

void setIsVolatile(bool isVolatile)

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

isVolatile true if backing pixels are temporary

Example

See Also

isVolatile


reset

void 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

static bool ComputeIsOpaque(const SkBitmap& bm)

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

bm Bitmap to check

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

void getBounds(SkRect* bounds) const

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

Parameters

bounds container for floating point rectangle

Example

See Also

bounds


void getBounds(SkIRect* bounds) const

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

Parameters

bounds container for integral rectangle

Example

See Also

bounds


bounds

SkIRect bounds() const

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

Return Value

integral rectangle from origin to width and height

Example

See Also

getBounds[2]


dimensions

SkISize dimensions() const

Returns ISize { width, height }.

Return Value

integral size of width and height

Example

See Also

height width


getSubset

SkIRect getSubset() const

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

bool setInfo(const SkImageInfo& imageInfo, size_t rowBytes = 0)

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:

rowBytes exceeds 31 bits
imageInfo.width is negative
imageInfo.height is negative
rowBytes is positive and less than imageInfo.width times imageInfo.bytesPerPixel

Parameters

imageInfo contains width, height, Alpha Type, Color Type, Color Space
rowBytes imageInfo.minRowBytes or larger; or zero

Return Value

true if Image Info set successfully

Example

See Also

Alpha Type Color Type Color Space height rowBytes width


Enum SkBitmap::AllocFlags

    enum AllocFlags {
        kZeroPixels AllocFlag = 1 << 0,
    };

AllocFlags provides the option to zero pixel memory when allocated.

Constants

Const Value Description
SkBitmap::kZeroPixels_AllocFlag 1 Instructs tryAllocPixelsFlags and allocPixelsFlags to zero pixel memory.

See Also

tryAllocPixelsFlags allocPixelsFlags erase eraseColor

Allocate

Topic Description
allocN32Pixels allocates compatible ARGB pixels, or aborts
allocPixels allocates pixels from Image Info, or aborts
allocPixels(const SkImageInfo& info, size t rowBytes)
allocPixels(const SkImageInfo& info)
allocPixels
allocPixels(Allocator* allocator)
allocPixelsFlags allocates pixels from Image Info with options, or aborts
installPixels creates Pixel Ref, with optional release function
installPixels(const SkImageInfo& info, void* pixels, size t rowBytes, void (*releaseProc) (void* addr, void* context) , void* context)
installPixels(const SkImageInfo& info, void* pixels, size t rowBytes)
installPixels(const SkPixmap& pixmap)
tryAllocN32Pixels allocates compatible ARGB pixels if possible
tryAllocPixels allocates pixels from Image Info if possible
tryAllocPixels(const SkImageInfo& info, size t rowBytes)
tryAllocPixels(const SkImageInfo& info)
tryAllocPixels
tryAllocPixels(Allocator* allocator)
tryAllocPixelsFlags allocates pixels from Image Info with options if possible

tryAllocPixelsFlags

bool SK_WARN_UNUSED_RESULT tryAllocPixelsFlags(const SkImageInfo& info, uint32_t flags)

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

info contains width, height, Alpha Type, Color Type, Color Space
flags kZeroPixels AllocFlag, or zero

Return Value

true if pixels allocation is successful

Example

#### Example Output ~~~~ bitmap allocation succeeded! ~~~~

See Also

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


allocPixelsFlags

void allocPixelsFlags(const SkImageInfo& info, uint32_t flags)

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

info contains width, height, Alpha Type, Color Type, Color Space
flags kZeroPixels AllocFlag, or zero

Example

Text is drawn on a transparent background; drawing the bitmap a second time lets the first draw show through.

See Also

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


tryAllocPixels

bool SK_WARN_UNUSED_RESULT tryAllocPixels(const SkImageInfo& info, size_t rowBytes)

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

info contains width, height, Alpha Type, Color Type, Color Space
rowBytes size of pixel row or larger; may be zero

Return Value

true if pixel storage is allocated

Example

See Also

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


allocPixels

void allocPixels(const SkImageInfo& info, size_t rowBytes)

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

info contains width, height, Alpha Type, Color Type, Color Space
rowBytes size of pixel row or larger; may be zero

Example

See Also

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


bool SK_WARN_UNUSED_RESULT tryAllocPixels(const SkImageInfo& info)

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

info contains width, height, Alpha Type, Color Type, Color Space

Return Value

true if pixel storage is allocated

Example

See Also

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


void allocPixels(const SkImageInfo& info)

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

info contains width, height, Alpha Type, Color Type, Color Space

Example

See Also

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


tryAllocN32Pixels

bool SK_WARN_UNUSED_RESULT tryAllocN32Pixels(int width, int height, bool isOpaque = false)

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

width pixel column count; must be zero or greater
height pixel row count; must be zero or greater
isOpaque true if pixels do not have transparency

Return Value

true if pixel storage is allocated

Example

See Also

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


allocN32Pixels

void allocN32Pixels(int width, int height, bool isOpaque = false)

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

width pixel column count; must be zero or greater
height pixel row count; must be zero or greater
isOpaque true if pixels do not have transparency

Example

See Also

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


installPixels

bool installPixels(const SkImageInfo& info, void* pixels, size_t rowBytes, void (*releaseProc)
                   (void* addr, void* context) , void* context)

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

info contains width, height, Alpha Type, Color Type, Color Space
pixels address or pixel storage; may be nullptr
rowBytes size of pixel row or larger
releaseProc function called when pixels can be deleted; may be nullptr
context caller state passed to releaseProc; may be nullptr

Return Value

true if Image Info is set to info

Example

releaseProc is called immediately because rowBytes is too small for Pixel Ref.

Example Output

before installPixels
releaseProc called
install not successful

See Also

allocPixels[2][3][4]


bool installPixels(const SkImageInfo& info, void* pixels, size_t rowBytes)

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

info contains width, height, Alpha Type, Color Type, Color Space
pixels address or pixel storage; may be nullptr
rowBytes size of pixel row or larger

Return Value

true if Image Info is set to info

Example

GPU does not support kUnpremul_SkAlphaType, does not assert that it does not.

See Also

allocPixels[2][3][4]


bool installPixels(const SkPixmap& pixmap)

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

pixmap Image Info, pixel address, and rowBytes

Return Value

true if Image Info was set to pixmap.info

Example

Draw a five by five bitmap, and draw it again with a center white pixel.

See Also

allocPixels[2][3][4]


installMaskPixels

bool installMaskPixels(const SkMask& mask)

Deprecated.

soon


Pixels

Topic Description
notifyPixelsChanged marks pixels as changed, altering the unique ID
peekPixels returns Pixmap if possible
readPixels copies and converts pixels
readPixels(const SkImageInfo& dstInfo, void* dstPixels, size t dstRowBytes, int srcX, int srcY) const
readPixels(const SkPixmap& dst, int srcX, int srcY) const
readPixels(const SkPixmap& dst) const
setPixels sets Pixel Ref without an offset
writePixels copies and converts pixels
writePixels(const SkPixmap& src, int dstX, int dstY)
writePixels(const SkPixmap& src)

setPixels

void setPixels(void* pixels)

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

pixels address of pixel storage, managed by caller

Example

See Also

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


bool SK_WARN_UNUSED_RESULT tryAllocPixels()

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

Bitmap hosts and draws gray values in set1. tryAllocPixels replaces Pixel Ref and erases it to black, but does not alter set1. setPixels replaces black Pixel Ref with set1.

See Also

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


void allocPixels()

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

Bitmap hosts and draws gray values in set1. allocPixels replaces Pixel Ref and erases it to black, but does not alter set1. setPixels replaces black Pixel Ref with set2.

See Also

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


bool SK_WARN_UNUSED_RESULT tryAllocPixels(Allocator* allocator)

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

allocator instance of SkBitmap::Allocator instantiation

Return Value

true if custom allocator reports success

Example

HeapAllocator limits the maximum size of Bitmap to two gigabytes. Using a custom allocator, this limitation may be relaxed. This example can be modified to allocate an eight gigabyte Bitmap on a 64-bit platform with sufficient memory.

See Also

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


void allocPixels(Allocator* allocator)

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

allocator instance of SkBitmap::Allocator instantiation

Example

See Also

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


pixelRef

SkPixelRef* pixelRef() const

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

SkIPoint pixelRefOrigin() const

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

Topic Description
setAlphaType sets Alpha Type of shared pixels
setHasHardwareMipMap sets Mip Map support present; Android only
setImmutable marks that pixels will not change
setInfo sets height, width, Color Type, and so on, releasing pixels
setIsVolatile marks if pixels should not be cached
setPixelRef sets Pixel Ref and offset

setPixelRef

void setPixelRef(sk sp<SkPixelRef> pixelRef, int dx, int dy)

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

pixelRef Pixel Ref describing pixel address and rowBytes
dx column offset in Pixel Ref for bitmap origin
dy row offset in Pixel Ref for bitmap origin

Example

Treating 32-bit data as 8-bit data is unlikely to produce useful results.

See Also

setInfo


readyToDraw

bool readyToDraw() const

Returns true if Bitmap is can be drawn.

Return Value

true if getPixels is not nullptr

Example

See Also

getPixels drawsNothing


getGenerationID

uint32_t getGenerationID() const

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

void notifyPixelsChanged() const

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

Example

See Also

getGenerationID isVolatile Pixel Ref


Draw

Topic Description
erase writes Color to rectangle of pixels
eraseARGB writes Color to pixels
eraseColor writes Color to pixels

eraseColor

void eraseColor(SkColor c) const

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

c Unpremultiplied Color

Example

See Also

eraseARGB erase


eraseARGB

void eraseARGB(U8CPU a, U8CPU r, U8CPU g, U8CPU b) const

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

a amount of Color Alpha, from fully transparent (0) to fully opaque (255)
r amount of red, from no red (0) to full red (255)
g amount of green, from no green (0) to full green (255)
b amount of blue, from no blue (0) to full blue (255)

Example

See Also

eraseColor erase


eraseRGB

void eraseRGB(U8CPU r, U8CPU g, U8CPU b) const

Deprecated.


erase

void erase(SkColor c, const SkIRect& area) const

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

c Unpremultiplied Color
area rectangle to fill

Example

See Also

eraseColor eraseARGB eraseRGB SkCanvas::drawRect


eraseArea

void eraseArea(const SkIRect& area, SkColor c) const

Deprecated.


getColor

SkColor getColor(int x, int y) const

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

x column index, zero or greater, and less than width
y row index, zero or greater, and less than height

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]


getAddr

void* getAddr(int x, int y) const

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

x column index, zero or greater, and less than width
y row index, zero or greater, and less than height

Return Value

generic pointer to pixel

Example

#### Example Output ~~~~ addr interval == rowBytes ~~~~

See Also

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


getAddr32

inline uint32_t* getAddr32(int x, int y) const

Returns address at (x, y).

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

Pixel Ref is nullptr
bytesPerPixel is not four
x is negative, or not less than width
y is negative, or not less than height

Parameters

x column index, zero or greater, and less than width
y row index, zero or greater, and less than height

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] SkPixmap::addr32[2]


getAddr16

inline uint16_t* getAddr16(int x, int y) const

Returns address at (x, y).

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

Pixel Ref is nullptr
bytesPerPixel is not two
x is negative, or not less than width
y is negative, or not less than height

Parameters

x column index, zero or greater, and less than width
y row index, zero or greater, and less than height

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] SkPixmap::addr16[2]


getAddr8

inline uint8_t* getAddr8(int x, int y) const

Returns address at (x, y).

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

Pixel Ref is nullptr
bytesPerPixel is not one
x is negative, or not less than width
y is negative, or not less than height

Parameters

x column index, zero or greater, and less than width
y row index, zero or greater, and less than height

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] SkPixmap::addr8[2]


extractSubset

bool extractSubset(SkBitmap* dst, const SkIRect& subset) const

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:

dst is nullptr
Pixel Ref is nullptr
subset does not intersect bounds

Parameters

dst Bitmap set to subset
subset rectangle of pixels to reference

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] writePixels[2] SkCanvas::drawBitmap


readPixels

bool readPixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dstRowBytes, int srcX, int srcY) const

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:

dstInfo.addr() equals nullptr
dstRowBytes is less than dstInfo.minRowBytes
Pixel Ref is nullptr

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

dstInfo destination width, height, Color Type, Alpha Type, Color Space
dstPixels destination pixel storage
dstRowBytes destination row length
srcX column index whose absolute value is less than width
srcY row index whose absolute value is less than height

Return Value

true if pixels are copied to dstPixels

Example

Transferring the gradient from 8 bits per component to 4 bits per component creates visible banding.

See Also

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


bool readPixels(const SkPixmap& dst, int srcX, int srcY) const

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:

dst pixel storage equals nullptr
dst.rowBytes is less than SkImageInfo::minRowBytes
Pixel Ref is nullptr

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

dst destination Pixmap: Image Info, pixels, row bytes
srcX column index whose absolute value is less than width
srcY row index whose absolute value is less than height

Return Value

true if pixels are copied to dst

Example

See Also

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


bool readPixels(const SkPixmap& dst) const

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:

dst pixel storage equals nullptr
dst.rowBytes is less than SkImageInfo::minRowBytes
Pixel Ref is nullptr

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

dst destination Pixmap: Image Info, pixels, row bytes

Return Value

true if pixels are copied to dst

Example

See Also

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


writePixels

bool writePixels(const SkPixmap& src, int dstX, int dstY)

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:

src pixel storage equals nullptr
src.rowBytes is less than SkImageInfo::minRowBytes
Pixel Ref is nullptr

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

src source Pixmap: Image Info, pixels, row bytes
dstX column index whose absolute value is less than width
dstY row index whose absolute value is less than height

Return Value

true if src pixels are copied to Bitmap

Example

See Also

readPixels[2][3]


bool writePixels(const SkPixmap& src)

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:

src pixel storage equals nullptr
src.rowBytes is less than SkImageInfo::minRowBytes
Pixel Ref is nullptr

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

src source Pixmap: Image Info, pixels, row bytes

Return Value

true if src pixels are copied to Bitmap

Example

See Also

readPixels[2][3]


hasHardwareMipMap

bool hasHardwareMipMap() const

For use by Android framework only.

Return Value

true if setHasHardwareMipMap has been called with true

See Also

setHasHardwareMipMap


setHasHardwareMipMap

void setHasHardwareMipMap(bool hasHardwareMipMap)

For use by Android framework only.

Parameters

hasHardwareMipMap sets state

See Also

hasHardwareMipMap


extractAlpha

bool extractAlpha(SkBitmap* dst) const

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

dst holds Pixel Ref to fill with alpha layer

Return Value

true if Alpha layer was constructed in dst Pixel Ref

Example

See Also

extractSubset


bool extractAlpha(SkBitmap* dst, const SkPaint* paint, SkIPoint* offset) const

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

dst holds Pixel Ref to fill with alpha layer
paint holds optional Mask Filter; may be nullptr
offset top-left position for dst; may be nullptr

Return Value

true if Alpha layer was constructed in dst Pixel Ref

Example

See Also

extractSubset


bool extractAlpha(SkBitmap* dst, const SkPaint* paint, Allocator* allocator, SkIPoint* offset) const

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

dst holds Pixel Ref to fill with alpha layer
paint holds optional Mask Filter; may be nullptr
allocator function to reserve memory for Pixel Ref; may be nullptr
offset top-left position for dst; may be nullptr

Return Value

true if Alpha layer was constructed in dst Pixel Ref

Example

See Also

extractSubset


peekPixels

bool peekPixels(SkPixmap* pixmap) const

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

pixmap storage for pixel state if pixels are readable; otherwise, ignored

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] writePixels[2]


Utility

Topic Description
ComputeIsOpaque returns true if all pixels are opaque
computeByteSize returns size required for pixels
getGenerationID returns unique ID
readyToDraw returns true if address of pixels is not nullptr
swap exchanges Bitmap pair
validate asserts if Bitmap is invalid (debug only)

validate

void validate() const;

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

See Also

SkImageInfo::validate