7f644ec996
bookmaker bot checked in more md files with the wrong fiddle hashes. Ravi is landing a CL to preventing it from checking in more errors, for now. Sadly, creating this CL also corrupted the md output -- luckily it was an error that could be detected. But perhaps other errors are going undetected. TMI: The call to fiddlecli wrote the wrong "text" string to SKIRect_isEmpty, first time I've seen that. Running it again generated the correct output. TBR=rmistry@google.com,jcgregario@google.com No-Try: true Docs-Preview: https://skia.org/?cl=142329 Bug: skia:6818 Change-Id: I6b57a4a070991b76a1acc44fb024439defc2d977 Reviewed-on: https://skia-review.googlesource.com/142329 Commit-Queue: Cary Clark <caryclark@google.com> Auto-Submit: Cary Clark <caryclark@google.com> Reviewed-by: Cary Clark <caryclark@google.com>
106 KiB
SkPixmap Reference
Pixmap
Class SkPixmap
Pixmap provides a utility to pair SkImageInfo with pixels and row bytes. Pixmap is a low level class which provides convenience functions to access raster destinations. Canvas can not draw Pixmap, nor does Pixmap provide a direct drawing destination.
Use Bitmap to draw pixels referenced by Pixmap; use Surface to draw into pixels referenced by Pixmap.
Pixmap does not try to manage the lifetime of the pixel memory. Use Pixel Ref to manage pixel memory; Pixel Ref is safe across threads.
Overview
| Topic | Description |
|---|---|
| Constructors | functions that construct SkPixmap |
| Functions | global and class member functions |
| Related Functions | similar member functions grouped together |
Related Function
SkPixmap global, struct, and class related member functions share a topic.
| Topic | Description |
|---|---|
| Image Info Access | returns all or part of Image Info |
| Initialization | sets fields for use |
| Pixels | read and write pixel values |
| Readable Address | returns read only pixels |
| Reader | examine pixel value |
| Writable Address | returns writable pixels |
Constructor
SkPixmap can be constructed or initialized by these functions, including C++ class constructors.
| Topic | Description |
|---|---|
| SkPixmap() | constructs with default values |
| SkPixmap(const SkImageInfo& info, const void* addr, size t rowBytes) | constructs from Image Info, pixels |
Member Function
SkPixmap member functions read and modify the structure properties.
| Topic | Description |
|---|---|
| addr | returns readable pixel address as void pointer |
| addr16 | returns readable pixel address as 16-bit pointer |
| addr32 | returns readable pixel address as 32-bit pointer |
| addr64 | returns readable pixel address as 64-bit pointer |
| addr8 | returns readable pixel address as 8-bit pointer |
| addrF16 | returns readable pixel component address as 16-bit pointer |
| alphaType | returns Image Info Alpha Type |
| bounds | returns width and height as Rectangle |
| colorSpace | returns Image Info Color Space |
| colorType | returns Image Info Color Type |
| computeByteSize | returns size required for pixels |
| computeIsOpaque | returns true if all pixels are opaque |
| erase | writes Color to pixels |
| extractSubset | sets pointer to portion of original |
| getColor | returns one pixel as Unpremultiplied Color |
| height | returns pixel row count |
| info | returns Image Info |
| isOpaque | returns true if Image Info describes opaque pixels |
| readPixels | copies and converts pixels |
| reset | reuses existing Pixmap with replacement values |
| rowBytes | returns interval between rows in bytes |
| rowBytesAsPixels | returns interval between rows in pixels |
| scalePixels | scales and converts pixels |
| setColorSpace | sets Image Info Color Space |
| shiftPerPixel | returns bit shift from pixels to bytes |
| width | returns pixel column count |
| writable addr | returns writable pixel address as void pointer |
| writable addr16 | returns writable pixel address as 16-bit pointer |
| writable addr32 | returns writable pixel address as 32-bit pointer |
| writable addr64 | returns writable pixel address as 64-bit pointer |
| writable addr8 | returns writable pixel address as 8-bit pointer |
| writable addrF16 | returns writable pixel component address as 16-bit pointer |
Initialization
SkPixmap
SkPixmap()
Creates an empty Pixmap without pixels, with kUnknown_SkColorType, with kUnknown_SkAlphaType, and with a width and height of zero. Use reset to associate pixels, SkColorType, SkAlphaType, width, and height after Pixmap has been created.
Return Value
empty Pixmap
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
SkPixmap(const SkImageInfo& info, const void* addr, size t rowBytes) reset[2][3] SkAlphaType SkColorType
SkPixmap
SkPixmap(const SkImageInfo& info, const void* addr, size_t rowBytes)
Creates Pixmap from info width, height, SkAlphaType, and SkColorType. addr points to pixels, or nullptr. rowBytes should be info.width times info.bytesPerPixel(), or larger.
No parameter checking is performed; it is up to the caller to ensure that addr and rowBytes agree with info.
The memory lifetime of pixels is managed by the caller. When Pixmap goes out of scope, addr is unaffected.
Pixmap may be later modified by reset to change its size, pixel type, or storage.
Parameters
info |
width, height, SkAlphaType, SkColorType of Image Info |
addr |
pointer to pixels allocated by caller; may be nullptr |
rowBytes |
size of one row of addr; width times pixel size, or larger |
Return Value
initialized Pixmap
Example
Example Output
image alpha only = false
copy alpha only = true
See Also
SkPixmap() reset[2][3] SkAlphaType SkColorType
reset
void reset()
Sets width, height, row bytes to zero; pixel address to nullptr; SkColorType to kUnknown_SkColorType; and SkAlphaType to kUnknown_SkAlphaType.
The prior pixels are unaffected; it is up to the caller to release pixels memory if desired.
Example
Example Output
width: 25 height: 35 color: kRGBA_8888_SkColorType alpha: kOpaque_SkAlphaType
width: 0 height: 0 color: kUnknown_SkColorType alpha: kUnknown_SkAlphaType
See Also
SkPixmap() SkAlphaType SkColorType
void reset(const SkImageInfo& info, const void* addr, size_t rowBytes)
Sets width, height, SkAlphaType, and SkColorType from info. Sets pixel address from addr, which may be nullptr. Sets row bytes from rowBytes, which should be info.width times info.bytesPerPixel(), or larger.
Does not check addr. Asserts if built with SK_DEBUG defined and if rowBytes is too small to hold one row of pixels.
The memory lifetime pixels are managed by the caller. When Pixmap goes out of scope, addr is unaffected.
Parameters
info |
width, height, SkAlphaType, SkColorType of Image Info |
addr |
pointer to pixels allocated by caller; may be nullptr |
rowBytes |
size of one row of addr; width times pixel size, or larger |
Example
See Also
SkPixmap(const SkImageInfo& info, const void* addr, size t rowBytes) reset[2][3] SkAlphaType SkColorType
setColorSpace
void setColorSpace(sk sp<SkColorSpace> colorSpace)
Changes Color Space in Image Info; preserves width, height, SkAlphaType, and SkColorType in Image, and leaves pixel address and row bytes unchanged. Color Space reference count is incremented.
Parameters
colorSpace |
Color Space moved to Image Info |
Example
Example Output
is unique
is not unique
See Also
Color Space SkImageInfo::makeColorSpace
bool SK_WARN_UNUSED_RESULT reset(const SkMask& mask)
Deprecated.
soon
extractSubset
bool SK_WARN_UNUSED_RESULT extractSubset(SkPixmap* subset, const SkIRect& area) const
Sets subset width, height, pixel address to intersection of Pixmap with area, if intersection is not empty; and return true. Otherwise, leave subset unchanged and return false.
Failing to read the return value generates a compile time warning.
Parameters
subset |
storage for width, height, pixel address of intersection |
area |
bounds to intersect with Pixmap |
Return Value
true if intersection of Pixmap and area is not empty
Example
See Also
reset[2][3] SkIRect::intersect[2][3]
Image Info Access
info
const SkImageInfo& info() const
Returns width, height, Alpha Type, Color Type, and Color Space.
Return Value
reference to ImageInfo
Example
Example Output
width: 384 height: 384 color: BGRA_8888 alpha: Opaque
See Also
rowBytes
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. It is up to the Bitmap creator to ensure that row bytes is a useful value.
Return Value
byte length of pixel row
Example
Example Output
rowBytes: 2 minRowBytes: 4
rowBytes: 8 minRowBytes: 4
See Also
addr[2] info SkImageInfo::minRowBytes
addr
const void* addr() const
Returns pixel address, the base address corresponding to the pixel origin.
It is up to the Pixmap creator to ensure that pixel address is a useful value.
Return Value
pixel address
Example
Example Output
#Volatile
pixels address: 0x7f2a440bb010
inset address: 0x7f2a440fb210
See Also
addr(int x, int y) addr8[2] addr16[2] addr32[2] addr64[2] info rowBytes
width
int width() const
Returns pixel count in each pixel row. Should be equal or less than:
rowBytes / info.bytesPerPixel().
Return Value
pixel width in Image Info
Example
Example Output
pixmap width: 16 info width: 16
See Also
height
int height() const
Returns pixel row count.
Return Value
pixel height in Image Info
Example
Example Output
pixmap height: 32 info height: 32
See Also
width ImageInfo::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
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
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
Example Output
gammaCloseToSRGB: false gammaIsLinear: true isSRGB: false
See Also
Color Space SkImageInfo::colorSpace
isOpaque
bool isOpaque() const
Returns true if Alpha Type is kOpaque_SkAlphaType. Does not check if Color Type allows Alpha, or if any pixel value has transparency.
Return Value
true if Image Info has opaque Alpha Type
Example
Example Output
isOpaque: false
isOpaque: false
isOpaque: true
isOpaque: true
See Also
computeIsOpaque SkImageInfo::isOpaque
bounds
SkIRect bounds() const
Returns IRect { 0, 0, width, height }.
Return Value
integral rectangle from origin to width and height
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
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 SkImageInfo::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
Example Output
color: kUnknown_SkColorType bytesPerPixel: 0 shiftPerPixel: 0
color: kAlpha_8_SkColorType bytesPerPixel: 1 shiftPerPixel: 0
color: kRGB_565_SkColorType bytesPerPixel: 2 shiftPerPixel: 1
color: kARGB_4444_SkColorType bytesPerPixel: 2 shiftPerPixel: 1
color: kRGBA_8888_SkColorType bytesPerPixel: 4 shiftPerPixel: 2
color: kBGRA_8888_SkColorType bytesPerPixel: 4 shiftPerPixel: 2
color: kGray_8_SkColorType bytesPerPixel: 1 shiftPerPixel: 0
color: kRGBA_F16_SkColorType bytesPerPixel: 8 shiftPerPixel: 3
See Also
rowBytes rowBytesAsPixels width SkImageInfo::bytesPerPixel
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
Reader
computeIsOpaque
bool computeIsOpaque() const
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.
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
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
Readable Address
const void* addr(int x, int y) const
Returns readable pixel address at (x, y). Returns nullptr if Pixel Ref is nullptr.
Input is not validated: out of bounds values of x or y trigger an assert() if built with SK_DEBUG defined. Returns nullptr if Color Type is kUnknown_SkColorType.
Performs a lookup of pixel size; for better performance, call one of: addr8, addr16, addr32, addr64, or addrF16.
Parameters
x |
column index, zero or greater, and less than width |
y |
row index, zero or greater, and less than height |
Return Value
readable generic pointer to pixel
Example
Example Output
pixmap.addr(1, 2) == &storage[1 + 2 * w]
See Also
addr8[2] addr16[2] addr32[2] addr64[2] addrF16[2] getColor writable addr[2] SkBitmap::getAddr
addr8
const uint8_t* addr8() const
Returns readable base pixel address. Result is addressable as unsigned 8-bit bytes. Will trigger an assert() if Color Type is not kAlpha_8_SkColorType or kGray_8_SkColorType, and is built with SK_DEBUG defined.
One byte corresponds to one pixel.
Return Value
readable unsigned 8-bit pointer to pixels
Example
Example Output
pixmap.addr8() == storage
See Also
addr[2] addr16[2] addr32[2] addr64[2] addrF16[2] getColor writable addr[2] writable addr8
addr16
const uint16_t* addr16() const
Returns readable base pixel address. Result is addressable as unsigned 16-bit words. Will trigger an assert() if Color Type is not kRGB_565_SkColorType or kARGB_4444_SkColorType, and is built with SK_DEBUG defined.
One word corresponds to one pixel.
Return Value
readable unsigned 16-bit pointer to pixels
Example
Example Output
pixmap.addr16() == storage
See Also
addr[2] addr8[2] addr32[2] addr64[2] addrF16[2] getColor writable addr[2] writable addr16
addr32
const uint32_t* addr32() const
Returns readable base pixel address. Result is addressable as unsigned 32-bit words. Will trigger an assert() if Color Type is not kRGBA_8888_SkColorType or kBGRA_8888_SkColorType, and is built with SK_DEBUG defined.
One word corresponds to one pixel.
Return Value
readable unsigned 32-bit pointer to pixels
Example
Example Output
pixmap.addr32() == storage
See Also
addr[2] addr8[2] addr16[2] addr64[2] addrF16[2] getColor writable addr[2] writable addr32
addr64
const uint64_t* addr64() const
Returns readable base pixel address. Result is addressable as unsigned 64-bit words. Will trigger an assert() if Color Type is not kRGBA_F16_SkColorType and is built with SK_DEBUG defined.
One word corresponds to one pixel.
Return Value
readable unsigned 64-bit pointer to pixels
Example
Example Output
pixmap.addr64() == storage
See Also
addr[2] addr8[2] addr16[2] addr32[2] addrF16[2] getColor writable addr[2] writable addr64
addrF16
const uint16_t* addrF16() const
Returns readable base pixel address. Result is addressable as unsigned 16-bit words. Will trigger an assert() if Color Type is not kRGBA_F16_SkColorType and is built with SK_DEBUG defined.
Each word represents one color component encoded as a half float. Four words correspond to one pixel.
Return Value
readable unsigned 16-bit pointer to first component of pixels
Example
Example Output
pixmap.addrF16() == storage
See Also
addr[2] addr8[2] addr16[2] addr32[2] addr64[2] getColor writable addr[2] writable addrF16
const uint8_t* addr8(int x, int y) const
Returns readable pixel address at (x, y).
Input is not validated: out of bounds values of x or y trigger an assert() if built with SK_DEBUG defined.
Will trigger an assert() if Color Type is not kAlpha_8_SkColorType or kGray_8_SkColorType, and is built with SK_DEBUG defined.
Parameters
x |
column index, zero or greater, and less than width |
y |
row index, zero or greater, and less than height |
Return Value
readable unsigned 8-bit pointer to pixel at (x, y)
Example
Example Output
pixmap.addr8(1, 2) == &storage[1 + 2 * w]
See Also
addr[2] addr16[2] addr32[2] addr64[2] addrF16[2] getColor writable addr[2] writable addr8
const uint16_t* addr16(int x, int y) const
Returns readable pixel address at (x, y).
Input is not validated: out of bounds values of x or y trigger an assert() if built with SK_DEBUG defined.
Will trigger an assert() if Color Type is not kRGB_565_SkColorType or kARGB_4444_SkColorType, and is built with SK_DEBUG defined.
Parameters
x |
column index, zero or greater, and less than width |
y |
row index, zero or greater, and less than height |
Return Value
readable unsigned 16-bit pointer to pixel at (x, y)
Example
Example Output
pixmap.addr16(1, 2) == &storage[1 + 2 * w]
See Also
addr[2] addr8[2] addr32[2] addr64[2] addrF16[2] getColor writable addr[2] writable addr16
const uint32_t* addr32(int x, int y) const
Returns readable pixel address at (x, y).
Input is not validated: out of bounds values of x or y trigger an assert() if built with SK_DEBUG defined.
Will trigger an assert() if Color Type is not kRGBA_8888_SkColorType or kBGRA_8888_SkColorType, and is built with SK_DEBUG defined.
Parameters
x |
column index, zero or greater, and less than width |
y |
row index, zero or greater, and less than height |
Return Value
readable unsigned 32-bit pointer to pixel at (x, y)
Example
Example Output
pixmap.addr32(1, 2) == &storage[1 + 2 * w]
See Also
addr[2] addr8[2] addr16[2] addr64[2] addrF16[2] getColor writable addr[2] writable addr64
const uint64_t* addr64(int x, int y) const
Returns readable pixel address at (x, y).
Input is not validated: out of bounds values of x or y trigger an assert() if built with SK_DEBUG defined.
Will trigger an assert() if Color Type is not kRGBA_F16_SkColorType and is built with SK_DEBUG defined.
Parameters
x |
column index, zero or greater, and less than width |
y |
row index, zero or greater, and less than height |
Return Value
readable unsigned 64-bit pointer to pixel at (x, y)
Example
Example Output
pixmap.addr64(1, 2) == &storage[1 + 2 * w]
See Also
addr[2] addr8[2] addr16[2] addr32[2] addrF16[2] getColor writable addr[2] writable addr64
const uint16_t* addrF16(int x, int y) const
Returns readable pixel address at (x, y).
Input is not validated: out of bounds values of x or y trigger an assert() if built with SK_DEBUG defined.
Will trigger an assert() if Color Type is not kRGBA_F16_SkColorType and is built with SK_DEBUG defined.
Each unsigned 16-bit word represents one color component encoded as a half float. Four words correspond to one pixel.
Parameters
x |
column index, zero or greater, and less than width |
y |
row index, zero or greater, and less than height |
Return Value
readable unsigned 16-bit pointer to pixel component at (x, y)
Example
Example Output
pixmap.addrF16(1, 2) == &storage[1 * wordsPerPixel + 2 * rowWords]
See Also
addr[2] addr8[2] addr16[2] addr32[2] addr64[2] getColor writable addr[2] writable addrF16
Writable Address
writable_addr
void* writable addr() const
Returns writable base pixel address.
Return Value
writable generic base pointer to pixels
Example
Example Output
pixmap.writable_addr() == (void *)storage
pixmap.getColor(0, 1) == 0x00000000
pixmap.getColor(0, 0) == 0xFFFFFFFF
See Also
writable addr8 writable addr16 writable addr32 writable addr64 writable addrF16 addr[2]
void* writable addr(int x, int y) const
Returns writable pixel address at (x, y).
Input is not validated: out of bounds values of x or y trigger an assert() if built with SK_DEBUG defined. Returns zero if Color Type is kUnknown_SkColorType.
Parameters
x |
column index, zero or greater, and less than width |
y |
row index, zero or greater, and less than height |
Return Value
writable generic pointer to pixel
Example
Example Output
pixmap.writable_addr() == (void *)storage
pixmap.getColor(0, 0) == 0x00000000
pixmap.getColor(1, 2) == 0xFFFFFFFF
See Also
writable addr8 writable addr16 writable addr32 writable addr64 writable addrF16 addr[2]
writable_addr8
uint8_t* writable addr8(int x, int y) const
Returns writable pixel address at (x, y). Result is addressable as unsigned 8-bit bytes. Will trigger an assert() if Color Type is not kAlpha_8_SkColorType or kGray_8_SkColorType, and is built with SK_DEBUG defined.
One byte corresponds to one pixel.
Parameters
x |
column index, zero or greater, and less than width |
y |
row index, zero or greater, and less than height |
Return Value
writable unsigned 8-bit pointer to pixels
Example
See Also
writable addr[2] writable addr16 writable addr32 writable addr64 writable addrF16 addr[2] addr8[2]
writable_addr16
uint16_t* writable addr16(int x, int y) const
Returns writable addr pixel address at (x, y). Result is addressable as unsigned 16-bit words. Will trigger an assert() if Color Type is not kRGB_565_SkColorType or kARGB_4444_SkColorType, and is built with SK_DEBUG defined.
One word corresponds to one pixel.
Parameters
x |
column index, zero or greater, and less than width |
y |
row index, zero or greater, and less than height |
Return Value
writable unsigned 16-bit pointer to pixel
Example
See Also
writable addr[2] writable addr8 writable addr32 writable addr64 writable addrF16 addr[2] addr16[2]
writable_addr32
uint32_t* writable addr32(int x, int y) const
Returns writable pixel address at (x, y). Result is addressable as unsigned 32-bit words. Will trigger an assert() if Color Type is not kRGBA_8888_SkColorType or kBGRA_8888_SkColorType, and is built with SK_DEBUG defined.
One word corresponds to one pixel.
Parameters
x |
column index, zero or greater, and less than width |
y |
row index, zero or greater, and less than height |
Return Value
writable unsigned 32-bit pointer to pixel
Example
See Also
writable addr[2] writable addr8 writable addr16 writable addr64 writable addrF16 addr[2] addr32[2]
writable_addr64
uint64_t* writable addr64(int x, int y) const
Returns writable pixel address at (x, y). Result is addressable as unsigned 64-bit words. Will trigger an assert() if Color Type is not kRGBA_F16_SkColorType and is built with SK_DEBUG defined.
One word corresponds to one pixel.
Parameters
x |
column index, zero or greater, and less than width |
y |
row index, zero or greater, and less than height |
Return Value
writable unsigned 64-bit pointer to pixel
Example
See Also
writable addr[2] writable addr8 writable addr16 writable addr32 writable addrF16 addr[2] addr64[2]
writable_addrF16
uint16_t* writable addrF16(int x, int y) const
Returns writable pixel address at (x, y). Result is addressable as unsigned 16-bit words. Will trigger an assert() if Color Type is not kRGBA_F16_SkColorType and is built with SK_DEBUG defined.
Each word represents one color component encoded as a half float. Four words correspond to one pixel.
Parameters
x |
column index, zero or greater, and less than width |
y |
row index, zero or greater, and less than height |
Return Value
writable unsigned 16-bit pointer to first component of pixel
Example
See Also
writable addr[2] writable addr8 writable addr16 writable addr32 writable addr64 addr[2] addrF16[2]
Pixels
| Topic | Description |
|---|---|
| erase | writes Color to pixels |
| erase(SkColor color, const SkIRect& subset) const | |
| erase(SkColor color) const | |
| erase(const SkColor4f& color, const SkIRect* subset = nullptr) const | |
| readPixels | copies and converts pixels |
| readPixels(const SkImageInfo& dstInfo, void* dstPixels, size t dstRowBytes) const | |
| 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 | |
| scalePixels | scales and converts pixels |
readPixels
bool readPixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dstRowBytes) const
Copies a Rect of pixels to dstPixels. Copy starts at (0, 0), and does not exceed Pixmap (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, or dstRowBytes is less than dstInfo.minRowBytes.
Pixels are copied only if pixel conversion is possible. If Pixmap colorType is kGray_8_SkColorType, or kAlpha_8_SkColorType; dstInfo.colorType must match. If Pixmap colorType is kGray_8_SkColorType, dstInfo.colorSpace must match. If Pixmap alphaType is kOpaque_SkAlphaType, dstInfo.alphaType must match. If Pixmap colorSpace is nullptr, dstInfo.colorSpace must match. Returns false if pixel conversion is not possible.
Returns false if Pixmap width or height is zero or negative.
Parameters
dstInfo |
destination width, height, Color Type, Alpha Type, Color Space |
dstPixels |
destination pixel storage |
dstRowBytes |
destination row length |
Return Value
true if pixels are copied to dstPixels
Example
See Also
erase[2][3] SkBitmap::readPixels[2][3] SkCanvas::drawBitmap SkCanvas::readPixels[2][3] SkImage::readPixels[2] SkSurface::readPixels[2][3]
bool readPixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dstRowBytes, int srcX, int srcY) const
Copies a Rect of pixels to dstPixels. Copy starts at (srcX, srcY), and does not exceed Pixmap (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, or dstRowBytes is less than dstInfo.minRowBytes.
Pixels are copied only if pixel conversion is possible. If Pixmap colorType is kGray_8_SkColorType, or kAlpha_8_SkColorType; dstInfo.colorType must match. If Pixmap colorType is kGray_8_SkColorType, dstInfo.colorSpace must match. If Pixmap alphaType is kOpaque_SkAlphaType, dstInfo.alphaType must match. If Pixmap 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 Pixmap width or height is zero or negative. Returns false if:
abs(srcX) >= Pixmap width, or ifabs(srcY) >= Pixmap 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
See Also
erase[2][3] SkBitmap::readPixels[2][3] SkCanvas::drawBitmap 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 to dst. Copy starts at (srcX, srcY), and does not exceed Pixmap (width, height). dst specifies width, height, Color Type, Alpha Type, and Color Space of destination. Returns true if pixels are copied. Returns false if dst.addr equals nullptr, or dst.rowBytes is less than dst SkImageInfo::minRowBytes.
Pixels are copied only if pixel conversion is possible. If Pixmap colorType is kGray_8_SkColorType, or kAlpha_8_SkColorType; dst.info.colorType must match. If Pixmap colorType is kGray_8_SkColorType, dst.info.colorSpace must match. If Pixmap alphaType is kOpaque_SkAlphaType, dst.info.alphaType must match. If Pixmap colorSpace is nullptr, dst.info.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 Pixmap width or height is zero or negative. Returns false if:
abs(srcX) >= Pixmap width, or ifabs(srcY) >= Pixmap height.
Parameters
dst |
Image Info and pixel address to write to |
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
erase[2][3] SkBitmap::readPixels[2][3] SkCanvas::drawBitmap SkCanvas::readPixels[2][3] SkImage::readPixels[2] SkSurface::readPixels[2][3]
bool readPixels(const SkPixmap& dst) const
Copies pixels inside bounds to dst. dst specifies width, height, Color Type, Alpha Type, and Color Space of destination. Returns true if pixels are copied. Returns false if dst.addr equals nullptr, or dst.rowBytes is less than dst SkImageInfo::minRowBytes.
Pixels are copied only if pixel conversion is possible. If Pixmap colorType is kGray_8_SkColorType, or kAlpha_8_SkColorType; dst Color Type must match. If Pixmap colorType is kGray_8_SkColorType, dst Color Space must match. If Pixmap alphaType is kOpaque_SkAlphaType, dst Alpha Type must match. If Pixmap colorSpace is nullptr, dst Color Space must match. Returns false if pixel conversion is not possible.
Returns false if Pixmap width or height is zero or negative.
Parameters
dst |
Image Info and pixel address to write to |
Return Value
true if pixels are copied to dst
Example
See Also
erase[2][3] SkBitmap::readPixels[2][3] SkCanvas::drawBitmap SkCanvas::readPixels[2][3] SkImage::readPixels[2] SkSurface::readPixels[2][3]
scalePixels
bool scalePixels(const SkPixmap& dst, SkFilterQuality filterQuality) const
Copies Bitmap to dst, scaling pixels to fit dst.width and dst.height, and converting pixels to match dst.colorType and dst.alphaType. Returns true if pixels are copied. Returns false if dst.addr is nullptr, or dst.rowBytes is less than dst SkImageInfo::minRowBytes.
Pixels are copied only if pixel conversion is possible. If Pixmap colorType is kGray_8_SkColorType, or kAlpha_8_SkColorType; dst Color Type must match. If Pixmap colorType is kGray_8_SkColorType, dst Color Space must match. If Pixmap alphaType is kOpaque_SkAlphaType, dst Alpha Type must match. If Pixmap colorSpace is nullptr, dst Color Space must match. Returns false if pixel conversion is not possible.
Returns false if Bitmap width or height is zero or negative.
Scales the image, with filterQuality, to match dst.width and dst.height. filterQuality kNone_SkFilterQuality is fastest, typically implemented with Filter Quality Nearest Neighbor. kLow_SkFilterQuality is typically implemented with Filter Quality Bilerp. kMedium_SkFilterQuality is typically implemented with Filter Quality Bilerp, and Filter Quality MipMap when size is reduced. kHigh_SkFilterQuality is slowest, typically implemented with Filter Quality BiCubic.
Parameters
dst |
Image Info and pixel address to write to |
filterQuality |
one of: kNone_SkFilterQuality, kLow_SkFilterQuality, kMedium_SkFilterQuality, kHigh_SkFilterQuality |
Return Value
true if pixels are scaled to fit dst
Example
See Also
SkCanvas::drawBitmap SkImage::scalePixels
erase
bool erase(SkColor color, const SkIRect& subset) const
Writes color to pixels bounded by subset; returns true on success. Returns false if colorType is kUnknown_SkColorType, or if subset does not intersect bounds.
Parameters
color |
Unpremultiplied Color to write |
subset |
bounding integer Rect of written pixels |
Return Value
true if pixels are changed
Example
See Also
SkBitmap::erase SkCanvas::clear SkCanvas::drawColor
bool erase(SkColor color) const
Writes color to pixels inside bounds; returns true on success. Returns false if colorType is kUnknown_SkColorType, or if bounds is empty.
Parameters
color |
Unpremultiplied Color to write |
Return Value
true if pixels are changed
Example
See Also
SkBitmap::erase SkCanvas::clear SkCanvas::drawColor
bool erase(const SkColor4f& color, const SkIRect* subset = nullptr) const
Writes color to pixels bounded by subset; returns true on success. if subset is nullptr, writes colors pixels inside bounds. Returns false if colorType is kUnknown_SkColorType, if subset is not nullptr and does not intersect bounds, or if subset is nullptr and bounds is empty.
Parameters
color |
Unpremultiplied Color to write |
subset |
bounding integer Rect of pixels to write; may be nullptr |
Return Value
true if pixels are changed
Example
See Also
SkBitmap::erase SkCanvas::clear SkCanvas::drawColor