skia2/include/core/SkRegion.h
Hal Canary 0d4f60c230 Docs: Add links to header files.
Change-Id: I5818b0dcfe58f086a25bd5a28ec2ab2d50c9985a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/201398
Commit-Queue: Joe Gregorio <jcgregorio@google.com>
Reviewed-by: Joe Gregorio <jcgregorio@google.com>
Auto-Submit: Hal Canary <halcanary@google.com>
2019-10-18 19:24:13 +00:00

688 lines
24 KiB
C++

/*
* Copyright 2005 The Android Open Source Project
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkRegion_DEFINED
#define SkRegion_DEFINED
#include "include/core/SkRect.h"
class SkPath;
class SkRgnBuilder;
/** \class SkRegion
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.
*/
class SK_API SkRegion {
typedef int32_t RunType;
public:
/** Constructs an empty SkRegion. SkRegion is set to empty bounds
at (0, 0) with zero width and height.
@return empty SkRegion
example: https://fiddle.skia.org/c/@Region_empty_constructor
*/
SkRegion();
/** 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.
@param region SkRegion to copy by value
@return copy of SkRegion
example: https://fiddle.skia.org/c/@Region_copy_const_SkRegion
*/
SkRegion(const SkRegion& region);
/** Constructs a rectangular SkRegion matching the bounds of rect.
@param rect bounds of constructed SkRegion
@return rectangular SkRegion
example: https://fiddle.skia.org/c/@Region_copy_const_SkIRect
*/
explicit SkRegion(const SkIRect& rect);
/** Releases ownership of any shared data and deletes data if SkRegion is sole owner.
example: https://fiddle.skia.org/c/@Region_destructor
*/
~SkRegion();
/** 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.
@param region SkRegion to copy by value
@return SkRegion to copy by value
example: https://fiddle.skia.org/c/@Region_copy_operator
*/
SkRegion& operator=(const SkRegion& region);
/** Compares SkRegion and other; returns true if they enclose exactly
the same area.
@param other SkRegion to compare
@return true if SkRegion pair are equivalent
example: https://fiddle.skia.org/c/@Region_equal1_operator
*/
bool operator==(const SkRegion& other) const;
/** Compares SkRegion and other; returns true if they do not enclose the same area.
@param other SkRegion to compare
@return true if SkRegion pair are not equivalent
*/
bool operator!=(const SkRegion& other) const {
return !(*this == other);
}
/** 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.
@param src SkRegion to copy
@return copy of src
*/
bool set(const SkRegion& src) {
*this = src;
return !this->isEmpty();
}
/** 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().
@param other operator=(const SkRegion& region) set
example: https://fiddle.skia.org/c/@Region_swap
*/
void swap(SkRegion& other);
/** 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.
@return true if bounds has no width or height
*/
bool isEmpty() const { return fRunHead == emptyRunHeadPtr(); }
/** Returns true if SkRegion is one SkIRect with positive dimensions.
@return true if SkRegion contains one SkIRect
*/
bool isRect() const { return fRunHead == kRectRunHeadPtr; }
/** Returns true if SkRegion is described by more than one rectangle.
@return true if SkRegion contains more than one SkIRect
*/
bool isComplex() const { return !this->isEmpty() && !this->isRect(); }
/** Returns minimum and maximum axes values of SkIRect array.
Returns (0, 0, 0, 0) if SkRegion is empty.
@return combined bounds of all SkIRect elements
*/
const SkIRect& getBounds() const { return fBounds; }
/** 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.
@return relative complexity
example: https://fiddle.skia.org/c/@Region_computeRegionComplexity
*/
int computeRegionComplexity() const;
/** Appends outline of SkRegion to path.
Returns true if SkRegion is not empty; otherwise, returns false, and leaves path
unmodified.
@param path SkPath to append to
@return true if path changed
example: https://fiddle.skia.org/c/@Region_getBoundaryPath
*/
bool getBoundaryPath(SkPath* path) const;
/** Constructs an empty SkRegion. SkRegion is set to empty bounds
at (0, 0) with zero width and height. Always returns false.
@return false
example: https://fiddle.skia.org/c/@Region_setEmpty
*/
bool setEmpty();
/** Constructs a rectangular SkRegion matching the bounds of rect.
If rect is empty, constructs empty and returns false.
@param rect bounds of constructed SkRegion
@return true if rect is not empty
example: https://fiddle.skia.org/c/@Region_setRect
*/
bool setRect(const SkIRect& rect);
/** 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().
@param rects array of SkIRect
@param count array size
@return true if constructed SkRegion is not empty
example: https://fiddle.skia.org/c/@Region_setRects
*/
bool setRects(const SkIRect rects[], int count);
/** 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.
@param region SkRegion to copy by value
@return SkRegion to copy by value
example: https://fiddle.skia.org/c/@Region_setRegion
*/
bool setRegion(const SkRegion& region);
/** 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.
@param path SkPath providing outline
@param clip SkRegion containing path
@return true if constructed SkRegion is not empty
example: https://fiddle.skia.org/c/@Region_setPath
*/
bool setPath(const SkPath& path, const SkRegion& clip);
/** Returns true if SkRegion intersects rect.
Returns false if either rect or SkRegion is empty, or do not intersect.
@param rect SkIRect to intersect
@return true if rect and SkRegion have area in common
example: https://fiddle.skia.org/c/@Region_intersects
*/
bool intersects(const SkIRect& rect) const;
/** Returns true if SkRegion intersects other.
Returns false if either other or SkRegion is empty, or do not intersect.
@param other SkRegion to intersect
@return true if other and SkRegion have area in common
example: https://fiddle.skia.org/c/@Region_intersects_2
*/
bool intersects(const SkRegion& other) const;
/** Returns true if SkIPoint (x, y) is inside SkRegion.
Returns false if SkRegion is empty.
@param x test SkIPoint x-coordinate
@param y test SkIPoint y-coordinate
@return true if (x, y) is inside SkRegion
example: https://fiddle.skia.org/c/@Region_contains
*/
bool contains(int32_t x, int32_t y) const;
/** Returns true if other is completely inside SkRegion.
Returns false if SkRegion or other is empty.
@param other SkIRect to contain
@return true if other is inside SkRegion
example: https://fiddle.skia.org/c/@Region_contains_2
*/
bool contains(const SkIRect& other) const;
/** Returns true if other is completely inside SkRegion.
Returns false if SkRegion or other is empty.
@param other SkRegion to contain
@return true if other is inside SkRegion
example: https://fiddle.skia.org/c/@Region_contains_3
*/
bool contains(const SkRegion& other) const;
/** Returns true if SkRegion is a single rectangle and contains r.
May return false even though SkRegion contains r.
@param r SkIRect to contain
@return true quickly if r points are equal or inside
*/
bool quickContains(const SkIRect& r) const {
SkASSERT(this->isEmpty() == fBounds.isEmpty()); // valid region
return r.fLeft < r.fRight && r.fTop < r.fBottom &&
fRunHead == kRectRunHeadPtr && // this->isRect()
/* fBounds.contains(left, top, right, bottom); */
fBounds.fLeft <= r.fLeft && fBounds.fTop <= r.fTop &&
fBounds.fRight >= r.fRight && fBounds.fBottom >= r.fBottom;
}
/** 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.
@param rect SkIRect to intersect
@return true if rect does not intersect
*/
bool quickReject(const SkIRect& rect) const {
return this->isEmpty() || rect.isEmpty() ||
!SkIRect::Intersects(fBounds, rect);
}
/** 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.
@param rgn SkRegion to intersect
@return true if rgn does not intersect
*/
bool quickReject(const SkRegion& rgn) const {
return this->isEmpty() || rgn.isEmpty() ||
!SkIRect::Intersects(fBounds, rgn.fBounds);
}
/** Offsets SkRegion by ivector (dx, dy). Has no effect if SkRegion is empty.
@param dx x-axis offset
@param dy y-axis offset
*/
void translate(int dx, int dy) { this->translate(dx, dy, this); }
/** 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.
@param dx x-axis offset
@param dy y-axis offset
@param dst translated result
example: https://fiddle.skia.org/c/@Region_translate_2
*/
void translate(int dx, int dy, SkRegion* dst) const;
/** \enum SkRegion::Op
The logical operations that can be performed when combining two SkRegion.
*/
enum Op {
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 = kReplace_Op, //!< last operator
};
static const int kOpCnt = kLastOp + 1;
/** Replaces SkRegion with the result of SkRegion op rect.
Returns true if replaced SkRegion is not empty.
@param rect SkIRect operand
@param op operator, one of:
kDifference_Op, kIntersect_Op, kUnion_Op, kXOR_Op, kReverseDifference_Op,
kReplace_Op
@return false if result is empty
*/
bool op(const SkIRect& rect, Op op) {
if (this->isRect() && kIntersect_Op == op) {
if (!fBounds.intersect(rect)) {
return this->setEmpty();
}
return true;
}
return this->op(*this, rect, op);
}
/** Replaces SkRegion with the result of SkRegion op rgn.
Returns true if replaced SkRegion is not empty.
@param rgn SkRegion operand
@param op operator, one of:
kDifference_Op, kIntersect_Op, kUnion_Op, kXOR_Op, kReverseDifference_Op,
kReplace_Op
@return false if result is empty
*/
bool op(const SkRegion& rgn, Op op) { return this->op(*this, rgn, op); }
/** Replaces SkRegion with the result of rect op rgn.
Returns true if replaced SkRegion is not empty.
@param rect SkIRect operand
@param rgn SkRegion operand
@param op operator, one of:
kDifference_Op, kIntersect_Op, kUnion_Op, kXOR_Op, kReverseDifference_Op,
kReplace_Op
@return false if result is empty
example: https://fiddle.skia.org/c/@Region_op_4
*/
bool op(const SkIRect& rect, const SkRegion& rgn, Op op);
/** Replaces SkRegion with the result of rgn op rect.
Returns true if replaced SkRegion is not empty.
@param rgn SkRegion operand
@param rect SkIRect operand
@param op operator, one of:
kDifference_Op, kIntersect_Op, kUnion_Op, kXOR_Op, kReverseDifference_Op,
kReplace_Op
@return false if result is empty
example: https://fiddle.skia.org/c/@Region_op_5
*/
bool op(const SkRegion& rgn, const SkIRect& rect, Op op);
/** Replaces SkRegion with the result of rgna op rgnb.
Returns true if replaced SkRegion is not empty.
@param rgna SkRegion operand
@param rgnb SkRegion operand
@param op operator, one of:
kDifference_Op, kIntersect_Op, kUnion_Op, kXOR_Op, kReverseDifference_Op,
kReplace_Op
@return false if result is empty
example: https://fiddle.skia.org/c/@Region_op_6
*/
bool op(const SkRegion& rgna, const SkRegion& rgnb, Op op);
#ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
/** Private. Android framework only.
@return string representation of SkRegion
*/
char* toString();
#endif
/** \class SkRegion::Iterator
Returns sequence of rectangles, sorted along y-axis, then x-axis, that make
up SkRegion.
*/
class SK_API Iterator {
public:
/** Initializes SkRegion::Iterator with an empty SkRegion. done() on SkRegion::Iterator
returns true.
Call reset() to initialized SkRegion::Iterator at a later time.
@return empty SkRegion iterator
*/
Iterator() : fRgn(nullptr), fDone(true) {}
/** Sets SkRegion::Iterator to return elements of SkIRect array in region.
@param region SkRegion to iterate
@return SkRegion iterator
example: https://fiddle.skia.org/c/@Region_Iterator_copy_const_SkRegion
*/
Iterator(const SkRegion& region);
/** SkPoint SkRegion::Iterator to start of SkRegion.
Returns true if SkRegion was set; otherwise, returns false.
@return true if SkRegion was set
example: https://fiddle.skia.org/c/@Region_Iterator_rewind
*/
bool rewind();
/** Resets iterator, using the new SkRegion.
@param region SkRegion to iterate
example: https://fiddle.skia.org/c/@Region_Iterator_reset
*/
void reset(const SkRegion& region);
/** Returns true if SkRegion::Iterator is pointing to final SkIRect in SkRegion.
@return true if data parsing is complete
*/
bool done() const { return fDone; }
/** Advances SkRegion::Iterator to next SkIRect in SkRegion if it is not done.
example: https://fiddle.skia.org/c/@Region_Iterator_next
*/
void next();
/** Returns SkIRect element in SkRegion. Does not return predictable results if SkRegion
is empty.
@return part of SkRegion as SkIRect
*/
const SkIRect& rect() const { return fRect; }
/** Returns SkRegion if set; otherwise, returns nullptr.
@return iterated SkRegion
*/
const SkRegion* rgn() const { return fRgn; }
private:
const SkRegion* fRgn;
const SkRegion::RunType* fRuns;
SkIRect fRect = {0, 0, 0, 0};
bool fDone;
};
/** \class SkRegion::Cliperator
Returns the sequence of rectangles, sorted along y-axis, then x-axis, that make
up SkRegion intersected with the specified clip rectangle.
*/
class SK_API Cliperator {
public:
/** Sets SkRegion::Cliperator to return elements of SkIRect array in SkRegion within clip.
@param region SkRegion to iterate
@param clip bounds of iteration
@return SkRegion iterator
example: https://fiddle.skia.org/c/@Region_Cliperator_const_SkRegion_const_SkIRect
*/
Cliperator(const SkRegion& region, const SkIRect& clip);
/** Returns true if SkRegion::Cliperator is pointing to final SkIRect in SkRegion.
@return true if data parsing is complete
*/
bool done() { return fDone; }
/** Advances iterator to next SkIRect in SkRegion contained by clip.
example: https://fiddle.skia.org/c/@Region_Cliperator_next
*/
void next();
/** Returns SkIRect element in SkRegion, intersected with clip passed to
SkRegion::Cliperator constructor. Does not return predictable results if SkRegion
is empty.
@return part of SkRegion inside clip as SkIRect
*/
const SkIRect& rect() const { return fRect; }
private:
Iterator fIter;
SkIRect fClip;
SkIRect fRect = {0, 0, 0, 0};
bool fDone;
};
/** \class SkRegion::Spanerator
Returns the line segment ends within SkRegion that intersect a horizontal line.
*/
class Spanerator {
public:
/** Sets SkRegion::Spanerator to return line segments in SkRegion on scan line.
@param region SkRegion to iterate
@param y horizontal line to intersect
@param left bounds of iteration
@param right bounds of iteration
@return SkRegion iterator
example: https://fiddle.skia.org/c/@Region_Spanerator_const_SkRegion_int_int_int
*/
Spanerator(const SkRegion& region, int y, int left, int right);
/** Advances iterator to next span intersecting SkRegion within line segment provided
in constructor. Returns true if interval was found.
@param left pointer to span start; may be nullptr
@param right pointer to span end; may be nullptr
@return true if interval was found
example: https://fiddle.skia.org/c/@Region_Spanerator_next
*/
bool next(int* left, int* right);
private:
const SkRegion::RunType* fRuns;
int fLeft, fRight;
bool fDone;
};
/** Writes SkRegion to buffer, and returns number of bytes written.
If buffer is nullptr, returns number number of bytes that would be written.
@param buffer storage for binary data
@return size of SkRegion
example: https://fiddle.skia.org/c/@Region_writeToMemory
*/
size_t writeToMemory(void* buffer) const;
/** Constructs SkRegion from buffer of size length. Returns bytes read.
Returned value will be multiple of four or zero if length was too small.
@param buffer storage for binary data
@param length size of buffer
@return bytes read
example: https://fiddle.skia.org/c/@Region_readFromMemory
*/
size_t readFromMemory(const void* buffer, size_t length);
private:
static constexpr int kOpCount = kReplace_Op + 1;
// T
// [B N L R S]
// S
static constexpr int kRectRegionRuns = 7;
struct RunHead;
static RunHead* emptyRunHeadPtr() { return (SkRegion::RunHead*) -1; }
static constexpr RunHead* kRectRunHeadPtr = nullptr;
// allocate space for count runs
void allocateRuns(int count);
void allocateRuns(int count, int ySpanCount, int intervalCount);
void allocateRuns(const RunHead& src);
SkDEBUGCODE(void dump() const;)
SkIRect fBounds;
RunHead* fRunHead;
void freeRuns();
/**
* Return the runs from this region, consing up fake runs if the region
* is empty or a rect. In those 2 cases, we use tmpStorage to hold the
* run data.
*/
const RunType* getRuns(RunType tmpStorage[], int* intervals) const;
// This is called with runs[] that do not yet have their interval-count
// field set on each scanline. That is computed as part of this call
// (inside ComputeRunBounds).
bool setRuns(RunType runs[], int count);
int count_runtype_values(int* itop, int* ibot) const;
bool isValid() const;
static void BuildRectRuns(const SkIRect& bounds,
RunType runs[kRectRegionRuns]);
// If the runs define a simple rect, return true and set bounds to that
// rect. If not, return false and ignore bounds.
static bool RunsAreARect(const SkRegion::RunType runs[], int count,
SkIRect* bounds);
/**
* If the last arg is null, just return if the result is non-empty,
* else store the result in the last arg.
*/
static bool Oper(const SkRegion&, const SkRegion&, SkRegion::Op, SkRegion*);
friend struct RunHead;
friend class Iterator;
friend class Spanerator;
friend class SkRegionPriv;
friend class SkRgnBuilder;
friend class SkFlatRegion;
};
#endif