SkRegion describes the set of pixels used to clip SkCanvas. More...

#include <SkRegion.h>

Classes
class	Cliperator
	Returns the sequence of rectangles, sorted along y-axis, then x-axis, that make up SkRegion intersected with the specified clip rectangle. More...

class	Iterator
	Returns sequence of rectangles, sorted along y-axis, then x-axis, that make up SkRegion. More...

class	Spanerator
	Returns the line segment ends within SkRegion that intersect a horizontal line. More...

Public Types
enum	Op { kDifference_Op , kIntersect_Op , kUnion_Op , kXOR_Op , kReverseDifference_Op , kReplace_Op , kLastOp = kReplace_Op }

using	sk_is_trivially_relocatable = std::true_type

Public Member Functions
	SkRegion ()
	Constructs an empty SkRegion. More...

	SkRegion (const SkRegion &region)
	Constructs a copy of an existing region. More...

	SkRegion (const SkIRect &rect)
	Constructs a rectangular SkRegion matching the bounds of rect. More...

	~SkRegion ()
	Releases ownership of any shared data and deletes data if SkRegion is sole owner. More...

SkRegion &	operator= (const SkRegion &region)
	Constructs a copy of an existing region. More...

bool	operator== (const SkRegion &other) const
	Compares SkRegion and other; returns true if they enclose exactly the same area. More...

bool	operator!= (const SkRegion &other) const
	Compares SkRegion and other; returns true if they do not enclose the same area. More...

bool	set (const SkRegion &src)
	Sets SkRegion to src, and returns true if src bounds is not empty. More...

void	swap (SkRegion &other)
	Exchanges SkIRect array of SkRegion and other. More...

bool	isEmpty () const
	Returns true if SkRegion is empty. More...

bool	isRect () const
	Returns true if SkRegion is one SkIRect with positive dimensions. More...

bool	isComplex () const
	Returns true if SkRegion is described by more than one rectangle. More...

const SkIRect &	getBounds () const
	Returns minimum and maximum axes values of SkIRect array. More...

int	computeRegionComplexity () const
	Returns a value that increases with the number of elements in SkRegion. More...

bool	getBoundaryPath (SkPath *path) const
	Appends outline of SkRegion to path. More...

bool	setEmpty ()
	Constructs an empty SkRegion. More...

bool	setRect (const SkIRect &rect)
	Constructs a rectangular SkRegion matching the bounds of rect. More...

bool	setRects (const SkIRect rects[], int count)
	Constructs SkRegion as the union of SkIRect in rects array. More...

bool	setRegion (const SkRegion &region)
	Constructs a copy of an existing region. More...

bool	setPath (const SkPath &path, const SkRegion &clip)
	Constructs SkRegion to match outline of path within clip. More...

bool	intersects (const SkIRect &rect) const
	Returns true if SkRegion intersects rect. More...

bool	intersects (const SkRegion &other) const
	Returns true if SkRegion intersects other. More...

bool	contains (int32_t x, int32_t y) const
	Returns true if SkIPoint (x, y) is inside SkRegion. More...

bool	contains (const SkIRect &other) const
	Returns true if other is completely inside SkRegion. More...

bool	contains (const SkRegion &other) const
	Returns true if other is completely inside SkRegion. More...

bool	quickContains (const SkIRect &r) const
	Returns true if SkRegion is a single rectangle and contains r. More...

bool	quickReject (const SkIRect &rect) const
	Returns true if SkRegion does not intersect rect. More...

bool	quickReject (const SkRegion &rgn) const
	Returns true if SkRegion does not intersect rgn. More...

void	translate (int dx, int dy)
	Offsets SkRegion by ivector (dx, dy). More...

void	translate (int dx, int dy, SkRegion *dst) const
	Offsets SkRegion by ivector (dx, dy), writing result to dst. More...

bool	op (const SkIRect &rect, Op op)
	Replaces SkRegion with the result of SkRegion op rect. More...

bool	op (const SkRegion &rgn, Op op)
	Replaces SkRegion with the result of SkRegion op rgn. More...

bool	op (const SkIRect &rect, const SkRegion &rgn, Op op)
	Replaces SkRegion with the result of rect op rgn. More...

bool	op (const SkRegion &rgn, const SkIRect &rect, Op op)
	Replaces SkRegion with the result of rgn op rect. More...

bool	op (const SkRegion &rgna, const SkRegion &rgnb, Op op)
	Replaces SkRegion with the result of rgna op rgnb. More...

size_t	writeToMemory (void *buffer) const
	Writes SkRegion to buffer, and returns number of bytes written. More...

size_t	readFromMemory (const void *buffer, size_t length)
	Constructs SkRegion from buffer of size length. More...

Static Public Attributes
static const int	kOpCnt = kLastOp + 1

Friends
struct	RunHead

class	Iterator

class	Spanerator

class	SkRegionPriv

class	SkRgnBuilder

class	SkFlatRegion

Detailed Description

SkRegion describes the set of pixels used to clip SkCanvas.

SkRegion is compact, efficiently storing a single integer rectangle, or a run length encoded array of rectangles. SkRegion may reduce the current SkCanvas clip, or may be drawn as one or more integer rectangles. SkRegion iterator returns the scan lines or rectangles contained by it, optionally intersecting a bounding rectangle.

Member Typedef Documentation

◆ sk_is_trivially_relocatable

using SkRegion::sk_is_trivially_relocatable = std::true_type

Member Enumeration Documentation

◆ Op

enum SkRegion::Op

Enumerator
kDifference_Op	target minus operand
kIntersect_Op	target intersected with operand
kUnion_Op	target unioned with operand
kXOR_Op	target exclusive or with operand
kReverseDifference_Op	operand minus target
kReplace_Op	replace target with operand
kLastOp	last operator

Constructor & Destructor Documentation

◆ SkRegion() [1/3]

SkRegion::SkRegion ( )

Constructs an empty SkRegion.

SkRegion is set to empty bounds at (0, 0) with zero width and height.

Returns: empty SkRegion

example: https://fiddle.skia.org/c/@Region_empty_constructor

◆ SkRegion() [2/3]

SkRegion::SkRegion ( const SkRegion & region )

Constructs a copy of an existing region.

Copy constructor makes two regions identical by value. Internally, region and the returned result share pointer values. The underlying SkRect array is copied when modified.

Creating a SkRegion copy is very efficient and never allocates memory. SkRegion are always copied by value from the interface; the underlying shared pointers are not exposed.

Parameters

region SkRegion to copy by value

Returns: copy of SkRegion

example: https://fiddle.skia.org/c/@Region_copy_const_SkRegion

◆ SkRegion() [3/3]

SkRegion::SkRegion ( const SkIRect & rect )

explicit

Constructs a rectangular SkRegion matching the bounds of rect.

Parameters

rect	bounds of constructed SkRegion

Returns: rectangular SkRegion

example: https://fiddle.skia.org/c/@Region_copy_const_SkIRect

◆ ~SkRegion()

SkRegion::~SkRegion ( )

Releases ownership of any shared data and deletes data if SkRegion is sole owner.

example: https://fiddle.skia.org/c/@Region_destructor

Member Function Documentation

◆ computeRegionComplexity()

int SkRegion::computeRegionComplexity ( ) const

Returns a value that increases with the number of elements in SkRegion.

Returns zero if SkRegion is empty. Returns one if SkRegion equals SkIRect; otherwise, returns value greater than one indicating that SkRegion is complex.

Call to compare SkRegion for relative complexity.

Returns: relative complexity

example: https://fiddle.skia.org/c/@Region_computeRegionComplexity

◆ contains() [1/3]

bool SkRegion::contains ( const SkIRect & other ) const

Returns true if other is completely inside SkRegion.

Returns false if SkRegion or other is empty.

Parameters

other SkIRect to contain

Returns: true if other is inside SkRegion

example: https://fiddle.skia.org/c/@Region_contains_2

◆ contains() [2/3]

bool SkRegion::contains ( const SkRegion & other ) const

Returns true if other is completely inside SkRegion.

Returns false if SkRegion or other is empty.

Parameters

other SkRegion to contain

Returns: true if other is inside SkRegion

example: https://fiddle.skia.org/c/@Region_contains_3

◆ contains() [3/3]

bool SkRegion::contains	(	int32_t	x,
		int32_t	y
	)		const

Returns true if SkIPoint (x, y) is inside SkRegion.

Returns false if SkRegion is empty.

Parameters

x	test SkIPoint x-coordinate
y	test SkIPoint y-coordinate

Returns: true if (x, y) is inside SkRegion

example: https://fiddle.skia.org/c/@Region_contains

◆ getBoundaryPath()

bool SkRegion::getBoundaryPath ( SkPath * path ) const

Appends outline of SkRegion to path.

Returns true if SkRegion is not empty; otherwise, returns false, and leaves path unmodified.

Parameters

path	SkPath to append to

Returns: true if path changed

example: https://fiddle.skia.org/c/@Region_getBoundaryPath

◆ getBounds()

const SkIRect& SkRegion::getBounds ( ) const

inline

Returns minimum and maximum axes values of SkIRect array.

Returns (0, 0, 0, 0) if SkRegion is empty.

Returns: combined bounds of all SkIRect elements

◆ intersects() [1/2]

bool SkRegion::intersects ( const SkIRect & rect ) const

Returns true if SkRegion intersects rect.

Returns false if either rect or SkRegion is empty, or do not intersect.

Parameters

rect	SkIRect to intersect

Returns: true if rect and SkRegion have area in common

example: https://fiddle.skia.org/c/@Region_intersects

◆ intersects() [2/2]

bool SkRegion::intersects ( const SkRegion & other ) const

Returns true if SkRegion intersects other.

Returns false if either other or SkRegion is empty, or do not intersect.

Parameters

other SkRegion to intersect

Returns: true if other and SkRegion have area in common

example: https://fiddle.skia.org/c/@Region_intersects_2

◆ isComplex()

bool SkRegion::isComplex ( ) const

inline

Returns true if SkRegion is described by more than one rectangle.

Returns: true if SkRegion contains more than one SkIRect

◆ isEmpty()

bool SkRegion::isEmpty ( ) const

inline

Returns true if SkRegion is empty.

Empty SkRegion has bounds width or height less than or equal to zero. SkRegion() constructs empty SkRegion; setEmpty() and setRect() with dimensionless data make SkRegion empty.

Returns: true if bounds has no width or height

◆ isRect()

bool SkRegion::isRect ( ) const

inline

Returns true if SkRegion is one SkIRect with positive dimensions.

Returns: true if SkRegion contains one SkIRect

◆ op() [1/5]

bool SkRegion::op	(	const SkIRect &	rect,
		const SkRegion &	rgn,
		Op	op
	)

Replaces SkRegion with the result of rect op rgn.

Returns true if replaced SkRegion is not empty.

Parameters

rect	SkIRect operand
rgn	SkRegion operand

Returns: false if result is empty

example: https://fiddle.skia.org/c/@Region_op_4

◆ op() [2/5]

bool SkRegion::op	(	const SkIRect &	rect,
		Op	op
	)

inline

Replaces SkRegion with the result of SkRegion op rect.

Returns true if replaced SkRegion is not empty.

Parameters

rect	SkIRect operand

Returns: false if result is empty

◆ op() [3/5]

bool SkRegion::op	(	const SkRegion &	rgn,
		const SkIRect &	rect,
		Op	op
	)

Replaces SkRegion with the result of rgn op rect.

Returns true if replaced SkRegion is not empty.

Parameters

rgn	SkRegion operand
rect	SkIRect operand

Returns: false if result is empty

example: https://fiddle.skia.org/c/@Region_op_5

◆ op() [4/5]

bool SkRegion::op	(	const SkRegion &	rgn,
		Op	op
	)

inline

Replaces SkRegion with the result of SkRegion op rgn.

Returns true if replaced SkRegion is not empty.

Parameters

rgn	SkRegion operand

Returns: false if result is empty

◆ op() [5/5]

bool SkRegion::op	(	const SkRegion &	rgna,
		const SkRegion &	rgnb,
		Op	op
	)

Replaces SkRegion with the result of rgna op rgnb.

Returns true if replaced SkRegion is not empty.

Parameters

rgna	SkRegion operand
rgnb	SkRegion operand

Returns: false if result is empty

example: https://fiddle.skia.org/c/@Region_op_6

◆ operator!=()

bool SkRegion::operator!= ( const SkRegion & other ) const

inline

Compares SkRegion and other; returns true if they do not enclose the same area.

Parameters

other SkRegion to compare

Returns: true if SkRegion pair are not equivalent

◆ operator=()

SkRegion& SkRegion::operator= ( const SkRegion & region )

Constructs a copy of an existing region.

Makes two regions identical by value. Internally, region and the returned result share pointer values. The underlying SkRect array is copied when modified.

Creating a SkRegion copy is very efficient and never allocates memory. SkRegion are always copied by value from the interface; the underlying shared pointers are not exposed.

Parameters

region SkRegion to copy by value

Returns: SkRegion to copy by value

example: https://fiddle.skia.org/c/@Region_copy_operator

◆ operator==()

bool SkRegion::operator== ( const SkRegion & other ) const

Compares SkRegion and other; returns true if they enclose exactly the same area.

Parameters

other SkRegion to compare

Returns: true if SkRegion pair are equivalent

example: https://fiddle.skia.org/c/@Region_equal1_operator

◆ quickContains()

bool SkRegion::quickContains ( const SkIRect & r ) const

inline

Returns true if SkRegion is a single rectangle and contains r.

May return false even though SkRegion contains r.

Parameters

r	SkIRect to contain

Returns: true quickly if r points are equal or inside

◆ quickReject() [1/2]

bool SkRegion::quickReject ( const SkIRect & rect ) const

inline

Returns true if SkRegion does not intersect rect.

Returns true if rect is empty or SkRegion is empty. May return false even though SkRegion does not intersect rect.

Parameters

rect	SkIRect to intersect

Returns: true if rect does not intersect

◆ quickReject() [2/2]

bool SkRegion::quickReject ( const SkRegion & rgn ) const

inline

Returns true if SkRegion does not intersect rgn.

Returns true if rgn is empty or SkRegion is empty. May return false even though SkRegion does not intersect rgn.

Parameters

rgn	SkRegion to intersect

Returns: true if rgn does not intersect

◆ readFromMemory()

size_t SkRegion::readFromMemory	(	const void *	buffer,
		size_t	length
	)

Constructs SkRegion from buffer of size length.

Returns bytes read. Returned value will be multiple of four or zero if length was too small.

Parameters

buffer	storage for binary data
length	size of buffer

Returns: bytes read

example: https://fiddle.skia.org/c/@Region_readFromMemory

◆ set()

bool SkRegion::set ( const SkRegion & src )

inline

Sets SkRegion to src, and returns true if src bounds is not empty.

This makes SkRegion and src identical by value. Internally, SkRegion and src share pointer values. The underlying SkRect array is copied when modified.

Creating a SkRegion copy is very efficient and never allocates memory. SkRegion are always copied by value from the interface; the underlying shared pointers are not exposed.

Parameters

src	SkRegion to copy

Returns: copy of src

◆ setEmpty()

bool SkRegion::setEmpty ( )

Constructs an empty SkRegion.

SkRegion is set to empty bounds at (0, 0) with zero width and height. Always returns false.

Returns: false

example: https://fiddle.skia.org/c/@Region_setEmpty

◆ setPath()

bool SkRegion::setPath	(	const SkPath &	path,
		const SkRegion &	clip
	)

Constructs SkRegion to match outline of path within clip.

Returns false if constructed SkRegion is empty.

Constructed SkRegion draws the same pixels as path through clip when anti-aliasing is disabled.

Parameters

path	SkPath providing outline
clip	SkRegion containing path

Returns: true if constructed SkRegion is not empty

example: https://fiddle.skia.org/c/@Region_setPath

◆ setRect()

bool SkRegion::setRect ( const SkIRect & rect )

Constructs a rectangular SkRegion matching the bounds of rect.

If rect is empty, constructs empty and returns false.

Parameters

rect	bounds of constructed SkRegion

Returns: true if rect is not empty

example: https://fiddle.skia.org/c/@Region_setRect

◆ setRects()

bool SkRegion::setRects	(	const SkIRect	rects[],
		int	count
	)

Constructs SkRegion as the union of SkIRect in rects array.

If count is zero, constructs empty SkRegion. Returns false if constructed SkRegion is empty.

May be faster than repeated calls to op().

Parameters

rects	array of SkIRect
count	array size

Returns: true if constructed SkRegion is not empty

example: https://fiddle.skia.org/c/@Region_setRects

◆ setRegion()

bool SkRegion::setRegion ( const SkRegion & region )

Constructs a copy of an existing region.

Makes two regions identical by value. Internally, region and the returned result share pointer values. The underlying SkRect array is copied when modified.

Creating a SkRegion copy is very efficient and never allocates memory. SkRegion are always copied by value from the interface; the underlying shared pointers are not exposed.

Parameters

region SkRegion to copy by value

Returns: SkRegion to copy by value

example: https://fiddle.skia.org/c/@Region_setRegion

◆ swap()

void SkRegion::swap ( SkRegion & other )

Exchanges SkIRect array of SkRegion and other.

swap() internally exchanges pointers, so it is lightweight and does not allocate memory.

swap() usage has largely been replaced by operator=(const SkRegion& region). SkPath do not copy their content on assignment until they are written to, making assignment as efficient as swap().

Parameters

other operator=(const SkRegion& region) set

example: https://fiddle.skia.org/c/@Region_swap

◆ translate() [1/2]

void SkRegion::translate	(	int	dx,
		int	dy
	)

inline

Offsets SkRegion by ivector (dx, dy).

Has no effect if SkRegion is empty.

Parameters

dx	x-axis offset
dy	y-axis offset

◆ translate() [2/2]

void SkRegion::translate	(	int	dx,
		int	dy,
		SkRegion *	dst
	)		const

Offsets SkRegion by ivector (dx, dy), writing result to dst.

SkRegion may be passed as dst parameter, translating SkRegion in place. Has no effect if dst is nullptr. If SkRegion is empty, sets dst to empty.

Parameters

dx	x-axis offset
dy	y-axis offset
dst	translated result

example: https://fiddle.skia.org/c/@Region_translate_2

◆ writeToMemory()

size_t SkRegion::writeToMemory ( void * buffer ) const

Writes SkRegion to buffer, and returns number of bytes written.

If buffer is nullptr, returns number number of bytes that would be written.

Parameters

buffer storage for binary data

Returns: size of SkRegion

example: https://fiddle.skia.org/c/@Region_writeToMemory

Friends And Related Function Documentation

◆ Iterator

friend class Iterator

friend

◆ RunHead

friend struct RunHead

friend

◆ SkFlatRegion

friend class SkFlatRegion

friend

◆ SkRegionPriv

friend class SkRegionPriv

friend

◆ SkRgnBuilder

friend class SkRgnBuilder

friend

◆ Spanerator

friend class Spanerator

friend

Member Data Documentation

◆ kOpCnt

const int SkRegion::kOpCnt = kLastOp + 1

static

The documentation for this class was generated from the following file:

/CHECKOUT/include/core/SkRegion.h

Classes

Public Types

Public Member Functions

Static Public Attributes

Friends

Detailed Description

Member Typedef Documentation

◆ sk_is_trivially_relocatable

Member Enumeration Documentation

◆ Op

Constructor & Destructor Documentation

◆ SkRegion() [1/3]

◆ SkRegion() [2/3]

◆ SkRegion() [3/3]

◆ ~SkRegion()

Member Function Documentation

◆ computeRegionComplexity()

◆ contains() [1/3]

◆ contains() [2/3]

◆ contains() [3/3]

◆ getBoundaryPath()

◆ getBounds()

◆ intersects() [1/2]

◆ intersects() [2/2]

◆ isComplex()

◆ isEmpty()

◆ isRect()

◆ op() [1/5]

◆ op() [2/5]

◆ op() [3/5]

◆ op() [4/5]

◆ op() [5/5]

◆ operator!=()

◆ operator=()

◆ operator==()

◆ quickContains()

◆ quickReject() [1/2]

◆ quickReject() [2/2]

◆ readFromMemory()

◆ set()

◆ setEmpty()

◆ setPath()

◆ setRect()

◆ setRects()

◆ setRegion()

◆ swap()

◆ translate() [1/2]

◆ translate() [2/2]

◆ writeToMemory()

Friends And Related Function Documentation

◆ Iterator

◆ RunHead

◆ SkFlatRegion

◆ SkRegionPriv

◆ SkRgnBuilder

◆ Spanerator

Member Data Documentation

◆ kOpCnt