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SkBitmap Reference


class SkBitmap {

    SkBitmap();
    SkBitmap(const SkBitmap& src);
    SkBitmap(SkBitmap&& src);
    ~SkBitmap();
    SkBitmap& operator=(const SkBitmap& src);
    SkBitmap& operator=(SkBitmap&& src);
    void swap(SkBitmap& other);
    const SkPixmap& pixmap() const;
    const SkImageInfo& info() const;
    int width() const;
    int height() const;
    SkColorType colorType() const;
    SkAlphaType alphaType() const;
    SkColorSpace* colorSpace() const;
    sk_sp<SkColorSpace> refColorSpace() const;
    int bytesPerPixel() const;
    int rowBytesAsPixels() const;
    int shiftPerPixel() const;
    bool empty() const;
    bool isNull() const;
    bool drawsNothing() const;
    size_t rowBytes() const;
    bool setAlphaType(SkAlphaType alphaType);
    void* getPixels() const;
    size_t computeByteSize() const;
    bool isImmutable() const;
    void setImmutable();
    bool isOpaque() const;
    bool isVolatile() const;
    void setIsVolatile(bool isVolatile);
    void reset();
    static bool ComputeIsOpaque(const SkBitmap& bm);
    void getBounds(SkRect* bounds) const;
    void getBounds(SkIRect* bounds) const;
    SkIRect bounds() const;
    SkISize dimensions() const;
    SkIRect getSubset() const;
    bool setInfo(const SkImageInfo& imageInfo, size_t rowBytes = 0);

    enum AllocFlags {
        kZeroPixels_AllocFlag = 1 << 0,
    };

    bool tryAllocPixelsFlags(const SkImageInfo& info, uint32_t flags);
    void allocPixelsFlags(const SkImageInfo& info, uint32_t flags);
    bool tryAllocPixels(const SkImageInfo& info, size_t rowBytes);
    void allocPixels(const SkImageInfo& info, size_t rowBytes);
    bool tryAllocPixels(const SkImageInfo& info);
    void allocPixels(const SkImageInfo& info);
    bool tryAllocN32Pixels(int width, int height, bool isOpaque = false);
    void allocN32Pixels(int width, int height, bool isOpaque = false);
    bool installPixels(const SkImageInfo& info, void* pixels, size_t rowBytes,
                       void (*releaseProc)(void* addr, void* context), void* context);
    bool installPixels(const SkImageInfo& info, void* pixels, size_t rowBytes);
    bool installPixels(const SkPixmap& pixmap);
    void setPixels(void* pixels);
    bool tryAllocPixels();
    void allocPixels();
    bool tryAllocPixels(Allocator* allocator);
    void allocPixels(Allocator* allocator);
    SkPixelRef* pixelRef() const;
    SkIPoint pixelRefOrigin() const;
    void setPixelRef(sk_sp<SkPixelRef> pixelRef, int dx, int dy);
    bool readyToDraw() const;
    uint32_t getGenerationID() const;
    void notifyPixelsChanged() const;
    void eraseColor(SkColor c) const;
    void eraseARGB(U8CPU a, U8CPU r, U8CPU g, U8CPU b) const;
    void erase(SkColor c, const SkIRect& area) const;
    SkColor getColor(int x, int y) const;
    float getAlphaf(int x, int y) const;
    void* getAddr(int x, int y) const;
    uint32_t* getAddr32(int x, int y) const;
    uint16_t* getAddr16(int x, int y) const;
    uint8_t* getAddr8(int x, int y) const;
    bool extractSubset(SkBitmap* dst, const SkIRect& subset) const;
    bool readPixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dstRowBytes,
                    int srcX, int srcY) const;
    bool readPixels(const SkPixmap& dst, int srcX, int srcY) const;
    bool readPixels(const SkPixmap& dst) const;
    bool writePixels(const SkPixmap& src, int dstX, int dstY);
    bool writePixels(const SkPixmap& src);
    bool extractAlpha(SkBitmap* dst) const;
    bool extractAlpha(SkBitmap* dst, const SkPaint* paint,
                      SkIPoint* offset) const;
    bool extractAlpha(SkBitmap* dst, const SkPaint* paint, Allocator* allocator,
                      SkIPoint* offset) const;
    bool peekPixels(SkPixmap* pixmap) const;
    void validate() const;
};

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.

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.


    class Allocator : public SkRefCnt {

        virtual bool allocPixelRef(SkBitmap* bitmap) = 0;
    };

Abstract subclass of HeapAllocator.


virtual bool allocPixelRef(SkBitmap* bitmap) = 0

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

Parameters

bitmap SkBitmap containing SkImageInfo as input, and SkPixelRef as output

Return Value

true if SkPixelRef was allocated

See Also

HeapAllocator


    class HeapAllocator : public Allocator {

        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.


bool allocPixelRef(SkBitmap* bitmap) override

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

Parameters

bitmap SkBitmap containing SkImageInfo as input, and SkPixelRef as output

Return Value

true if pixels are allocated

Example

#### Example Output ~~~~ #Volatile pixel address = (nil) pixel address = 0x560ddd0ac670 ~~~~

See Also

SkBitmap::Allocator tryAllocPixels


SkBitmap()

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

Use setInfo() to associate SkColorType, SkAlphaType, width, and height after SkBitmap has been created.

Return Value

empty SkBitmap

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(const SkBitmap& src)

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

Parameters

src SkBitmap to copy SkImageInfo, and share SkPixelRef

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&& src)

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

Parameters

src SkBitmap to copy SkImageInfo, and reassign SkPixelRef

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 SkPixelRef reference count, if SkPixelRef is not nullptr.

See Also

Pixel_Ref


SkBitmap& operator=(const SkBitmap& src)

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

Parameters

src SkBitmap to copy SkImageInfo, and share SkPixelRef

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& operator=(SkBitmap&& src)

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

Parameters

src SkBitmap to copy SkImageInfo, and reassign SkPixelRef

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


void swap(SkBitmap& other)

Swaps the fields of the two bitmaps.

Parameters

other SkBitmap 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)


const SkPixmap& pixmap()const

Returns a constant reference to the SkPixmap holding the SkBitmap pixel address, row bytes, and SkImageInfo.

Return Value

reference to SkPixmap describing this SkBitmap

Example

#### Example Output ~~~~ ---------- ---xx----- --x--x---- --x------- --xx------ --x-x---x- -x---x--x- -x----xx-- -xx---x--- --xxxx-xx- ---------- ~~~~

See Also

peekPixels installPixels readPixels writePixels


const SkImageInfo& info()const

Returns width, height, SkAlphaType, SkColorType, and SkColorSpace.

Return Value

reference to SkImageInfo

Example

#### Example Output ~~~~ width: 56 height: 56 color: BGRA_8888 alpha: Opaque ~~~~

See Also

Image_Info


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()


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 SkImageInfo

Example

#### Example Output ~~~~ bitmap height: 32 info height: 32 ~~~~

See Also

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


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


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


SkColorSpace* colorSpace()const

Returns SkColorSpace, the range of colors, associated with SkImageInfo. The reference count of SkColorSpace is unchanged. The returned SkColorSpace is immutable.

Return Value

SkColorSpace in SkImageInfo, 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


sk_sp<SkColorSpace> refColorSpace()const

Returns smart pointer to SkColorSpace, the range of colors, associated with SkImageInfo. The smart pointer tracks the number of objects sharing this SkColorSpace reference so the memory is released when the owners destruct.

The returned SkColorSpace is immutable.

Return Value

SkColorSpace in SkImageInfo wrapped in a smart pointer

Example

#### Example Output ~~~~ gammaCloseToSRGB: false gammaIsLinear: true isSRGB: false ~~~~

See Also

Color_Space SkImageInfo::colorSpace


int bytesPerPixel()const

Returns number of bytes per pixel required by SkColorType. 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


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


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


bool empty()const

Returns true if either width() or height() are zero.

Does not check if SkPixelRef is nullptr; call drawsNothing() to check width(), height(), and SkPixelRef.

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


bool isNull()const

Returns true if SkPixelRef is nullptr.

Does not check if width() or height() are zero; call drawsNothing() to check width(), height(), and SkPixelRef.

Return Value

true if no SkPixelRef 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


bool drawsNothing()const

Returns true if width() or height() are zero, or if SkPixelRef is nullptr. If true, SkBitmap 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


size_t rowBytes()const

Returns row bytes, the interval from one pixel row to the next. Row bytes is at least as large as: width() * 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


bool setAlphaType(SkAlphaType alphaType)

Sets SkAlphaType, if alphaType is compatible with SkColorType. Returns true unless alphaType is kUnknown_SkAlphaType and current SkAlphaType is not kUnknown_SkAlphaType.

Returns true if SkColorType is kUnknown_SkColorType. alphaType is ignored, and SkAlphaType remains kUnknown_SkAlphaType.

Returns true if SkColorType is kRGB_565_SkColorType or kGray_8_SkColorType. alphaType is ignored, and SkAlphaType remains kOpaque_SkAlphaType.

If SkColorType is kARGB_4444_SkColorType, kRGBA_8888_SkColorType, kBGRA_8888_SkColorType, or kRGBA_F16_SkColorType: returns true unless alphaType is kUnknown_SkAlphaType and SkAlphaType is not kUnknown_SkAlphaType. If SkAlphaType is kUnknown_SkAlphaType, alphaType is ignored.

If SkColorType is kAlpha_8_SkColorType, returns true unless alphaType is kUnknown_SkAlphaType and SkAlphaType is not kUnknown_SkAlphaType. If SkAlphaType is kUnknown_SkAlphaType, alphaType is ignored. If alphaType is kUnpremul_SkAlphaType, it is treated as kPremul_SkAlphaType.

This changes SkAlphaType in SkPixelRef; all bitmaps sharing SkPixelRef are affected.

Parameters

alphaType one of:

kUnknown_SkAlphaType, kOpaque_SkAlphaType, kPremul_SkAlphaType, kUnpremul_SkAlphaType

Return Value

true if SkAlphaType 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


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


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


bool isImmutable()const

Returns true if pixels can not change.

Most immutable SkBitmap 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


void setImmutable()

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

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

Example

Triggers assert if SK_DEBUG is true, runs fine otherwise.

See Also

isImmutable SkPixelRef::setImmutable SkImage


bool isOpaque()const

Returns true if SkAlphaType is set to hint that all pixels are opaque; their alpha value is implicitly or explicitly 1.0. If true, and all pixels are not opaque, Skia may draw incorrectly.

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

Return Value

true if SkImageInfo SkAlphaType 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


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 SkPixelRef.

Return Value

true if marked volatile

Example

#### Example Output ~~~~ original is volatile copy is not volatile ~~~~

See Also

setIsVolatile


void setIsVolatile(bool isVolatile)

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

Parameters

isVolatile true if backing pixels are temporary

Example

See Also

isVolatile


void reset()

Resets to its initial state; all fields are set to zero, as if SkBitmap 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 SkPixelRef is allocated, its reference count is decreased by one, releasing its memory if SkBitmap is the sole owner.

Example

#### Example Output ~~~~ width:1 height:1 isNull:false width:0 height:0 isNull:true ~~~~

See Also

SkBitmap() SkAlphaType SkColorType


static bool ComputeIsOpaque(const SkBitmap& bm)

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

For SkColorType kRGB_565_SkColorType or kGray_8_SkColorType: always returns true. For SkColorType kAlpha_8_SkColorType, kBGRA_8888_SkColorType, kRGBA_8888_SkColorType: returns true if all pixel alpha values are 255. For SkColorType 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 SkBitmap to check

Return Value

true if all pixels have opaque values or SkColorType is opaque

Example

#### Example Output ~~~~ computeIsOpaque: false computeIsOpaque: true computeIsOpaque: false computeIsOpaque: true ~~~~

See Also

isOpaque Color_Type Alpha


void getBounds(SkRect* bounds)const

Returns SkRect { 0, 0, width(), height() }.

Parameters

bounds container for floating point rectangle

Example

See Also

bounds()


void getBounds(SkIRect* bounds)const

Returns SkIRect { 0, 0, width(), height() }.

Parameters

bounds container for integral rectangle

Example

See Also

bounds()


SkIRect bounds()const

Returns SkIRect { 0, 0, width(), height() }.

Return Value

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

Example

See Also

getBounds


SkISize dimensions()const

Returns SkISize { width(), height() }.

Return Value

integral size of width() and height()

Example

See Also

height width


SkIRect getSubset()const

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

Return Value

bounds within SkPixelRef bounds

Example

#### Example Output ~~~~ source: 0, 0, 512, 512 subset: 100, 100, 412, 412 ~~~~

See Also

extractSubset getBounds


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 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


bool tryAllocPixelsFlags(const SkImageInfo& info, uint32_t flags)

Sets SkImageInfo 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 SkImageInfo 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, SkAlphaType, SkColorType, SkColorSpace
flags kZeroPixels_AllocFlag, or zero

Return Value

true if pixels allocation is successful

Example

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

See Also

allocPixelsFlags tryAllocPixels SkMallocPixelRef::MakeZeroed


void allocPixelsFlags(const SkImageInfo& info, uint32_t flags)

Sets SkImageInfo to info following the rules in setInfo() and allocates pixel memory. If flags is kZeroPixels_AllocFlag, memory is zeroed.

Aborts execution if SkImageInfo 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, SkAlphaType, SkColorType, SkColorSpace
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 SkMallocPixelRef::MakeZeroed


bool tryAllocPixels(const SkImageInfo& info, size_t rowBytes)

Sets SkImageInfo 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 SkImageInfo 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, SkAlphaType, SkColorType, SkColorSpace
rowBytes size of pixel row or larger; may be zero

Return Value

true if pixel storage is allocated

Example

See Also

tryAllocPixelsFlags allocPixels SkMallocPixelRef::MakeAllocate


void allocPixels(const SkImageInfo& info, size_t rowBytes)

Sets SkImageInfo 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 SkImageInfo 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, SkAlphaType, SkColorType, SkColorSpace
rowBytes size of pixel row or larger; may be zero

Example

See Also

tryAllocPixels allocPixelsFlags SkMallocPixelRef::MakeAllocate


bool tryAllocPixels(const SkImageInfo& info)

Sets SkImageInfo to info following the rules in setInfo() and allocates pixel memory.

Returns false and calls reset() if SkImageInfo 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, SkAlphaType, SkColorType, SkColorSpace

Return Value

true if pixel storage is allocated

Example

See Also

tryAllocPixelsFlags allocPixels SkMallocPixelRef::MakeAllocate


void allocPixels(const SkImageInfo& info)

Sets SkImageInfo to info following the rules in setInfo() and allocates pixel memory.

Aborts execution if SkImageInfo 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, SkAlphaType, SkColorType, SkColorSpace

Example

See Also

tryAllocPixels allocPixelsFlags SkMallocPixelRef::MakeAllocate


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

Sets SkImageInfo to width, height, and native color type; and allocates pixel memory. If isOpaque is true, sets SkImageInfo 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 SkBitmap that matches SkPMColor, the native pixel arrangement on the platform. SkBitmap 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 allocN32Pixels SkMallocPixelRef::MakeAllocate


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

Sets SkImageInfo to width, height, and the native color type; and allocates pixel memory. If isOpaque is true, sets SkImageInfo 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 SkBitmap that matches SkPMColor, the native pixel arrangement on the platform. SkBitmap 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 tryAllocN32Pixels SkMallocPixelRef::MakeAllocate


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

Sets SkImageInfo to info following the rules in setInfo(), and creates SkPixelRef 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 SkImageInfo 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 SkImageInfo, calls releaseProc if present, returns true.

If SkImageInfo 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, SkAlphaType, SkColorType, SkColorSpace
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 SkImageInfo 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


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

Sets SkImageInfo to info following the rules in setInfo(), and creates SkPixelRef containing pixels and rowBytes.

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

Otherwise, if pixels equals nullptr: sets SkImageInfo, returns true.

Caller must ensure that pixels are valid for the lifetime of SkBitmap and SkPixelRef.

Parameters

info contains width, height, SkAlphaType, SkColorType, SkColorSpace
pixels address or pixel storage; may be nullptr
rowBytes size of pixel row or larger

Return Value

true if SkImageInfo is set to info

Example

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

See Also

allocPixels


bool installPixels(const SkPixmap& pixmap)

Sets SkImageInfo to pixmap.info() following the rules in setInfo(), and creates SkPixelRef containing pixmap.addr() and pixmap.rowBytes().

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

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

Caller must ensure that pixmap is valid for the lifetime of SkBitmap and SkPixelRef.

Parameters

pixmap SkImageInfo, pixel address, and rowBytes()

Return Value

true if SkImageInfo was set to pixmap.info()

Example

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

See Also

allocPixels


void setPixels(void* pixels)

Replaces SkPixelRef with pixels, preserving SkImageInfo and rowBytes(). Sets SkPixelRef origin to (0, 0).

If pixels is nullptr, or if info().colorType() equals kUnknown_SkColorType; release reference to SkPixelRef, and set SkPixelRef to nullptr.

Caller is responsible for handling ownership pixel memory for the lifetime of SkBitmap and SkPixelRef.

Parameters

pixels address of pixel storage, managed by caller

Example

See Also

installPixels allocPixels


bool tryAllocPixels()

Allocates pixel memory with HeapAllocator, and replaces existing SkPixelRef. The allocation size is determined by SkImageInfo width, height, and SkColorType.

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 installPixels setPixels


void allocPixels()

Allocates pixel memory with HeapAllocator, and replaces existing SkPixelRef. The allocation size is determined by SkImageInfo width, height, and SkColorType.

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 installPixels setPixels


bool tryAllocPixels(Allocator* allocator)

Allocates pixel memory with allocator, and replaces existing SkPixelRef. The allocation size is determined by SkImageInfo width, height, and SkColorType. 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 Allocator Pixel_Ref


void allocPixels(Allocator* allocator)

Allocates pixel memory with allocator, and replaces existing SkPixelRef. The allocation size is determined by SkImageInfo width, height, and SkColorType. 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 Allocator Pixel_Ref


SkPixelRef* pixelRef()const

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

Return Value

SkPixelRef, or nullptr

Example

See Also

getPixels getAddr


SkIPoint pixelRefOrigin()const

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

The returned origin added to SkBitmap dimensions equals or is smaller than the SkPixelRef dimensions.

Returns (0, 0) if SkPixelRef is nullptr.

Return Value

pixel origin within SkPixelRef

Example

#### Example Output ~~~~ source origin: 0, 0 subset origin: 32, 64 ~~~~

See Also

SkPixelRef getSubset setPixelRef


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

Replaces pixelRef and origin in SkBitmap. dx and dy specify the offset within the SkPixelRef 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 SkColorType and SkAlphaType in SkImageInfo.

Parameters

pixelRef SkPixelRef describing pixel address and rowBytes()
dx column offset in SkPixelRef for bitmap origin
dy row offset in SkPixelRef for bitmap origin

Example

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

See Also

setInfo


bool readyToDraw()const

Returns true if SkBitmap is can be drawn.

Return Value

true if getPixels() is not nullptr

Example

See Also

getPixels drawsNothing


uint32_t getGenerationID()const

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

Determines if pixels have changed since last examined.

Return Value

unique value for pixels in SkPixelRef

Example

#### Example Output ~~~~ #Volatile empty id 0 alloc id 4 erase id 6 ~~~~

See Also

notifyPixelsChanged Pixel_Ref


void notifyPixelsChanged()const

Marks that pixels in SkPixelRef have changed. Subsequent calls to getGenerationID() return a different value.

Example

See Also

getGenerationID isVolatile Pixel_Ref


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 kRGB_565_SkColorType, then 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


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 kRGB_565_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 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


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 kRGB_565_SkColorType, then 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 SkCanvas::drawRect


SkColor getColor(int x, int y)const

Returns pixel at (x, y) as unpremultiplied color. Returns black with alpha if SkColorType 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 SkColorType is kUnknown_SkColorType or pixel address is nullptr.

SkColorSpace in SkImageInfo 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

getAlphaf getAddr readPixels


float getAlphaf(int x, int y)const

Looks up the pixel at (x,y) and return its alpha component, normalized to [0..1]. This is roughly equivalent to SkGetColorA(getColor()), but can be more efficient (and more precise if the pixels store more than 8 bits per component).

Parameters

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

Return Value

alpha converted to normalized float

See Also

getColor


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 SkColorType is kUnknown_SkColorType, or SkPixelRef 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 SkPixmap::addr


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 SkPixmap::addr32


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 SkPixmap::addr16


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 SkPixmap::addr8


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 writePixels SkCanvas::drawBitmap


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 has no address
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 if abs(srcX) >= Bitmap width(), or if abs(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 SkPixmap::readPixels SkCanvas::readPixels SkImage::readPixels SkSurface::readPixels


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 if abs(srcX) >= Bitmap width(), or if abs(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 SkPixmap::readPixels SkCanvas::readPixels SkImage::readPixels SkSurface::readPixels


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 SkPixmap::readPixels SkCanvas::readPixels SkImage::readPixels SkSurface::readPixels


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 if abs(dstX) >= Bitmap width(), or if abs(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


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


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 SkPixelRef.

Parameters

dst holds SkPixelRef to fill with alpha layer

Return Value

true if alpha layer was constructed in dst SkPixelRef

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 SkMaskFilter, SkMaskFilter generates mask alpha from SkBitmap. Uses HeapAllocator to reserve memory for dst SkPixelRef. Sets offset to top-left position for dst for alignment with SkBitmap; (0, 0) unless SkMaskFilter generates mask.

Parameters

dst holds SkPixelRef to fill with alpha layer
paint holds optional SkMaskFilter; may be nullptr
offset top-left position for dst; may be nullptr

Return Value

true if alpha layer was constructed in dst SkPixelRef

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 SkMaskFilter, SkMaskFilter generates mask alpha from SkBitmap. 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 SkBitmap; (0, 0) unless SkMaskFilter generates mask.

Parameters

dst holds SkPixelRef to fill with alpha layer
paint holds optional SkMaskFilter; may be nullptr
allocator function to reserve memory for SkPixelRef; may be nullptr
offset top-left position for dst; may be nullptr

Return Value

true if alpha layer was constructed in dst SkPixelRef

Example

See Also

extractSubset


bool peekPixels(SkPixmap* pixmap)const

Copies SkBitmap pixel address, row bytes, and SkImageInfo 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 SkBitmap.

Parameters

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

Return Value

true if SkBitmap has direct access to pixels

Example

#### Example Output ~~~~ ------ -xxx-- x---x- ----x- ---x-- --x--- --x--- ------ --x--- --x--- ------ ~~~~

See Also

pixmap installPixels readPixels writePixels


void validate() const;

See Also

SkImageInfo::validate