skia2/site/user/api/SkPath_Reference.md

SkPath Reference

---

class SkPath {
public:
    enum Direction {
        kCW_Direction,
        kCCW_Direction,
    };

    SkPath();
    SkPath(const SkPath& path);
    ~SkPath();
    SkPath& operator=(const SkPath& path);
    friend bool operator==(const SkPath& a, const SkPath& b);
    friend bool operator!=(const SkPath& a, const SkPath& b);
    bool isInterpolatable(const SkPath& compare) const;
    bool interpolate(const SkPath& ending, SkScalar weight, SkPath* out) const;
    bool unique() const;

    enum FillType {
        kWinding_FillType,
        kEvenOdd_FillType,
        kInverseWinding_FillType,
        kInverseEvenOdd_FillType,
    };

    FillType getFillType() const;
    void setFillType(FillType ft);
    bool isInverseFillType() const;
    void toggleInverseFillType();

    enum Convexity : uint8_t {
        kUnknown_Convexity,
        kConvex_Convexity,
        kConcave_Convexity,
    };

    Convexity getConvexity() const;
    Convexity getConvexityOrUnknown() const;
    void setConvexity(Convexity convexity);
    bool isConvex() const;
    bool isOval(SkRect* bounds) const;
    bool isRRect(SkRRect* rrect) const;
    SkPath& reset();
    SkPath& rewind();
    bool isEmpty() const;
    bool isLastContourClosed() const;
    bool isFinite() const;
    bool isVolatile() const;
    void setIsVolatile(bool isVolatile);
    static bool IsLineDegenerate(const SkPoint& p1, const SkPoint& p2, bool exact);
    static bool IsQuadDegenerate(const SkPoint& p1, const SkPoint& p2,
                                 const SkPoint& p3, bool exact);
    static bool IsCubicDegenerate(const SkPoint& p1, const SkPoint& p2,
                                  const SkPoint& p3, const SkPoint& p4, bool exact);
    bool isLine(SkPoint line[2]) const;
    int countPoints() const;
    SkPoint getPoint(int index) const;
    int getPoints(SkPoint points[], int max) const;
    int countVerbs() const;
    int getVerbs(uint8_t verbs[], int max) const;
    void swap(SkPath& other);
    const SkRect& getBounds() const;
    void updateBoundsCache() const;
    SkRect computeTightBounds() const;
    bool conservativelyContainsRect(const SkRect& rect) const;
    void incReserve(int extraPtCount);
    void shrinkToFit();
    SkPath& moveTo(SkScalar x, SkScalar y);
    SkPath& moveTo(const SkPoint& p);
    SkPath& rMoveTo(SkScalar dx, SkScalar dy);
    SkPath& lineTo(SkScalar x, SkScalar y);
    SkPath& lineTo(const SkPoint& p);
    SkPath& rLineTo(SkScalar dx, SkScalar dy);
    SkPath& quadTo(SkScalar x1, SkScalar y1, SkScalar x2, SkScalar y2);
    SkPath& quadTo(const SkPoint& p1, const SkPoint& p2);
    SkPath& rQuadTo(SkScalar dx1, SkScalar dy1, SkScalar dx2, SkScalar dy2);
    SkPath& conicTo(SkScalar x1, SkScalar y1, SkScalar x2, SkScalar y2,
                    SkScalar w);
    SkPath& conicTo(const SkPoint& p1, const SkPoint& p2, SkScalar w);
    SkPath& rConicTo(SkScalar dx1, SkScalar dy1, SkScalar dx2, SkScalar dy2,
                     SkScalar w);
    SkPath& cubicTo(SkScalar x1, SkScalar y1, SkScalar x2, SkScalar y2,
                    SkScalar x3, SkScalar y3);
    SkPath& cubicTo(const SkPoint& p1, const SkPoint& p2, const SkPoint& p3);
    SkPath& rCubicTo(SkScalar x1, SkScalar y1, SkScalar x2, SkScalar y2,
                     SkScalar x3, SkScalar y3);
    SkPath& arcTo(const SkRect& oval, SkScalar startAngle, SkScalar sweepAngle, bool forceMoveTo);
    SkPath& arcTo(SkScalar x1, SkScalar y1, SkScalar x2, SkScalar y2, SkScalar radius);
    SkPath& arcTo(const SkPoint p1, const SkPoint p2, SkScalar radius);

    enum ArcSize {
        kSmall_ArcSize,
        kLarge_ArcSize,
    };

    SkPath& arcTo(SkScalar rx, SkScalar ry, SkScalar xAxisRotate, ArcSize largeArc,
                  Direction sweep, SkScalar x, SkScalar y);
    SkPath& arcTo(const SkPoint r, SkScalar xAxisRotate, ArcSize largeArc, Direction sweep,
               const SkPoint xy);
    SkPath& rArcTo(SkScalar rx, SkScalar ry, SkScalar xAxisRotate, ArcSize largeArc,
                   Direction sweep, SkScalar dx, SkScalar dy);
    SkPath& close();
    static bool IsInverseFillType(FillType fill);
    static FillType ConvertToNonInverseFillType(FillType fill);
    static int ConvertConicToQuads(const SkPoint& p0, const SkPoint& p1, const SkPoint& p2,
                                   SkScalar w, SkPoint pts[], int pow2);
    bool isRect(SkRect* rect, bool* isClosed = nullptr, Direction* direction = nullptr) const;
    bool isNestedFillRects(SkRect rect[2], Direction dirs[2] = nullptr) const;
    SkPath& addRect(const SkRect& rect, Direction dir = kCW_Direction);
    SkPath& addRect(const SkRect& rect, Direction dir, unsigned start);
    SkPath& addRect(SkScalar left, SkScalar top, SkScalar right, SkScalar bottom,
                    Direction dir = kCW_Direction);
    SkPath& addOval(const SkRect& oval, Direction dir = kCW_Direction);
    SkPath& addOval(const SkRect& oval, Direction dir, unsigned start);
    SkPath& addCircle(SkScalar x, SkScalar y, SkScalar radius,
                      Direction dir = kCW_Direction);
    SkPath& addArc(const SkRect& oval, SkScalar startAngle, SkScalar sweepAngle);
    SkPath& addRoundRect(const SkRect& rect, SkScalar rx, SkScalar ry,
                         Direction dir = kCW_Direction);
    SkPath& addRoundRect(const SkRect& rect, const SkScalar radii[],
                         Direction dir = kCW_Direction);
    SkPath& addRRect(const SkRRect& rrect, Direction dir = kCW_Direction);
    SkPath& addRRect(const SkRRect& rrect, Direction dir, unsigned start);
    SkPath& addPoly(const SkPoint pts[], int count, bool close);
    SkPath& addPoly(const std::initializer_list<SkPoint>& list, bool close);

    enum AddPathMode {
        kAppend_AddPathMode,
        kExtend_AddPathMode,
    };

    SkPath& addPath(const SkPath& src, SkScalar dx, SkScalar dy,
                    AddPathMode mode = kAppend_AddPathMode);
    SkPath& addPath(const SkPath& src, AddPathMode mode = kAppend_AddPathMode);
    SkPath& addPath(const SkPath& src, const SkMatrix& matrix,
                    AddPathMode mode = kAppend_AddPathMode);
    SkPath& reverseAddPath(const SkPath& src);
    void offset(SkScalar dx, SkScalar dy, SkPath* dst) const;
    void offset(SkScalar dx, SkScalar dy);
    void transform(const SkMatrix& matrix, SkPath* dst) const;
    void transform(const SkMatrix& matrix);
    bool getLastPt(SkPoint* lastPt) const;
    void setLastPt(SkScalar x, SkScalar y);
    void setLastPt(const SkPoint& p);

    enum SegmentMask {
        kLine_SegmentMask = 1 << 0,
        kQuad_SegmentMask = 1 << 1,
        kConic_SegmentMask = 1 << 2,
        kCubic_SegmentMask = 1 << 3,
    };

    uint32_t getSegmentMasks() const;

    enum Verb {
        kMove_Verb,
        kLine_Verb,
        kQuad_Verb,
        kConic_Verb,
        kCubic_Verb,
        kClose_Verb,
        kDone_Verb,
    };

    class Iter {
    public:
        Iter();
        Iter(const SkPath& path, bool forceClose);
        void setPath(const SkPath& path, bool forceClose);
        Verb next(SkPoint pts[4], bool doConsumeDegenerates = true, bool exact = false);
        SkScalar conicWeight() const;
        bool isCloseLine() const;
        bool isClosedContour() const;
    };

    class RawIter {
    public:
        RawIter();
        RawIter(const SkPath& path);
        void setPath(const SkPath& path);
        Verb next(SkPoint pts[4]);
        Verb peek() const;
        SkScalar conicWeight() const;
    };

    bool contains(SkScalar x, SkScalar y) const;
    void dump(SkWStream* stream, bool forceClose, bool dumpAsHex) const;
    void dump() const;
    void dumpHex() const;
    size_t writeToMemory(void* buffer) const;
    sk_sp<SkData> serialize() const;
    size_t readFromMemory(const void* buffer, size_t length);
    uint32_t getGenerationID() const;
    bool isValid() const;
    bool isValid() const;
    bool pathRefIsValid() const;
};

Paths contain geometry. Paths may be empty, or contain one or more Verbs that outline a figure. Path always starts with a move verb to a Cartesian Coordinate, and may be followed by additional verbs that add lines or curves. Adding a close verb makes the geometry into a continuous loop, a closed contour. Paths may contain any number of contours, each beginning with a move verb.

Path contours may contain only a move verb, or may also contain lines, Quadratic Beziers, Conics, and Cubic Beziers. Path contours may be open or closed.

When used to draw a filled area, Path describes whether the fill is inside or outside the geometry. Path also describes the winding rule used to fill overlapping contours.

Internally, Path lazily computes metrics likes bounds and convexity. Call SkPath::updateBoundsCache to make Path thread safe.

---

    enum Verb {
        kMove_Verb,
        kLine_Verb,
        kQuad_Verb,
        kConic_Verb,
        kCubic_Verb,
        kClose_Verb,
        kDone_Verb,
    };

Verb instructs Path how to interpret one or more Point and optional Conic Weight; manage Contour, and terminate Path.

Constants

Each Verb has zero or more Points stored in Path. Path iterator returns complete curve descriptions, duplicating shared Points for consecutive entries.

Const	Value	Description
SkPath::kMove_Verb	0	Consecutive kMove Verb are preserved but all but the last kMove Verb is ignored. kMove Verb after other Verbs implicitly closes the previous Contour if SkPaint::kFill Style is set when drawn; otherwise, stroke is drawn open. kMove Verb as the last Verb is preserved but ignored.
SkPath::kLine_Verb	1	Line is a straight segment from Point to Point. Consecutive kLine Verb extend Contour. kLine Verb at same position as prior kMove Verb is preserved, and draws Point if SkPaint::kStroke Style is set, and SkPaint::Cap is SkPaint::kSquare Cap or SkPaint::kRound Cap. kLine Verb at same position as prior line or curve Verb is preserved but is ignored.
SkPath::kQuad_Verb	2	Adds Quad from Last Point, using control Point, and end Point. Quad is a parabolic section within tangents from Last Point to control Point, and control Point to end Point.
SkPath::kConic_Verb	3	Adds Conic from Last Point, using control Point, end Point, and Conic Weight. Conic is a elliptical, parabolic, or hyperbolic section within tangents from Last Point to control Point, and control Point to end Point, constrained by Conic Weight. Conic Weight less than one is elliptical; equal to one is parabolic (and identical to Quad); greater than one hyperbolic.
SkPath::kCubic_Verb	4	Adds Cubic from Last Point, using two control Points, and end Point. Cubic is a third-order Bezier Curve section within tangents from Last Point to first control Point, and from second control Point to end Point.
SkPath::kClose_Verb	5	Closes Contour, connecting Last Point to kMove Verb Point. Consecutive kClose Verb are preserved but only first has an effect. kClose Verb after kMove Verb has no effect.
SkPath::kDone_Verb	6	Not in Verb Array, but returned by Path iterator.

Verb	Allocated Points	Iterated Points	Weights
kMove Verb	1	1	0
kLine Verb	1	2	0
kQuad Verb	2	3	0
kConic Verb	2	3	1
kCubic Verb	3	4	0
kClose Verb	0	1	0
kDone Verb	--	0	0

Example

Example Output

verb count: 7
verbs: kMove_Verb kLine_Verb kQuad_Verb kClose_Verb kMove_Verb kCubic_Verb kConic_Verb

---

    enum Direction {
        kCW_Direction,
        kCCW_Direction,
    };

Direction describes whether Contour is clockwise or counterclockwise. When Path contains multiple overlapping Contours, Direction together with Fill Type determines whether overlaps are filled or form holes.

Direction also determines how Contour is measured. For instance, dashing measures along Path to determine where to start and stop stroke; Direction will change dashed results as it steps clockwise or counterclockwise.

Closed Contours like Rect, Round Rect, Circle, and Oval added with kCW Direction travel clockwise; the same added with kCCW Direction travel counterclockwise.

Constants

Const	Value	Description
SkPath::kCW_Direction	0	contour travels clockwise
SkPath::kCCW_Direction	1	contour travels counterclockwise

Example

See Also

arcTo^[2][3][4][5] rArcTo isRect isNestedFillRects addRect^[2][3] addOval^[2]

---

SkPath()

Constucts an empty Path. By default, Path has no Verbs, no Points, and no Weights. Fill Type is set to kWinding FillType.

Return Value

empty Path

Example

Example Output

path is empty

See Also

reset rewind

---

SkPath(const SkPath& path)

Constructs a copy of an existing path. Copy constructor makes two paths identical by value. Internally, path and the returned result share pointer values. The underlying Verb Array, Point Array and Weights are copied when modified.

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

Parameters

path	Path to copy by value

Return Value

copy of Path

Example

Modifying one path does not effect another, even if they started as copies of each other.

Example Output

path verbs: 2
path2 verbs: 3
after reset
path verbs: 0
path2 verbs: 3

See Also

operator=(const SkPath& path)

---

~SkPath()

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

Example

delete calls Path Destructor, but copy of original in path2 is unaffected.

See Also

SkPath() SkPath(const SkPath& path) operator=(const SkPath& path)

---

SkPath& operator=(const SkPath& path)

Constructs a copy of an existing path. Path assignment makes two paths identical by value. Internally, assignment shares pointer values. The underlying Verb Array, Point Array and Weights are copied when modified.

Copying Paths by assignment is very efficient and never allocates memory. Paths are always copied by value from the interface; the underlying shared pointers are not exposed.

Parameters

path	Verb Array, Point Array, Weights, and Fill Type to copy

Return Value

Path copied by value

Example

Example Output

path1 bounds = 10, 20, 30, 40
path2 bounds = 10, 20, 30, 40

See Also

swap SkPath(const SkPath& path)

---

bool operator==(const SkPath& a, const SkPath& b)

Compares a and b; returns true if Fill Type, Verb Array, Point Array, and Weights are equivalent.

Parameters

a	Path to compare
b	Path to compare

Return Value

true if Path pair are equivalent

Example

Rewind removes Verb Array but leaves storage; since storage is not compared, Path pair are equivalent.

Example Output

empty one == two
moveTo one != two
rewind one == two
reset one == two

See Also

operator!=(const SkPath& a, const SkPath& b) operator=(const SkPath& path)

---

bool operator!=(const SkPath& a, const SkPath& b)

Compares a and b; returns true if Fill Type, Verb Array, Point Array, and Weights are not equivalent.

Parameters

a	Path to compare
b	Path to compare

Return Value

true if Path pair are not equivalent

Example

Path pair are equal though their convexity is not equal.

Example Output

empty one == two
add rect one == two
setConvexity one == two
convexity !=

---

bool isInterpolatable(const SkPath& compare) const

Returns true if Paths contain equal Verbs and equal Weights. If Paths contain one or more Conics, the Weights must match.

conicTo may add different Verbs depending on Conic Weight, so it is not trivial to interpolate a pair of Paths containing Conics with different Conic Weight values.

Parameters

compare

Path to compare

Return Value

true if Paths Verb Array and Weights are equivalent

Example

Example Output

paths are interpolatable

See Also

isInterpolatable

---

bool interpolate(const SkPath& ending, SkScalar weight, SkPath* out) const

Interpolates between Paths with Point Array of equal size. Copy Verb Array and Weights to out, and set out Point Array to a weighted average of this Point Array and ending Point Array, using the formula: (Path Point * weight) + ending Point * (1 - weight).

weight is most useful when between zero (ending Point Array) and one (this Point Array); will work with values outside of this range.

interpolate() returns false and leaves out unchanged if Point Array is not the same size as ending Point Array. Call isInterpolatable to check Path compatibility prior to calling interpolate().

Parameters

ending	Point Array averaged with this Point Array
weight	contribution of this Point Array, and one minus contribution of ending Point Array
out	Path replaced by interpolated averages

Return Value

true if Paths contain same number of Points

Example

See Also

isInterpolatable

---

bool unique() const

To be deprecated soon.

Only valid for Android framework.

---

    enum FillType {
        kWinding_FillType,
        kEvenOdd_FillType,
        kInverseWinding_FillType,
        kInverseEvenOdd_FillType,
    };

Fill Type selects the rule used to fill Path. Path set to kWinding FillType fills if the sum of Contour edges is not zero, where clockwise edges add one, and counterclockwise edges subtract one. Path set to kEvenOdd FillType fills if the number of Contour edges is odd. Each Fill Type has an inverse variant that reverses the rule: kInverseWinding FillType fills where the sum of Contour edges is zero; kInverseEvenOdd FillType fills where the number of Contour edges is even.

Example

The top row has two clockwise rectangles. The second row has one clockwise and one counterclockwise rectangle. The even-odd variants draw the same. The winding variants draw the top rectangle overlap, which has a winding of 2, the same as the outer parts of the top rectangles, which have a winding of 1.

Constants

Const	Value	Description
SkPath::kWinding_FillType	0	is enclosed by a non-zero sum of Contour Directions
SkPath::kEvenOdd_FillType	1	is enclosed by an odd number of Contours
SkPath::kInverseWinding_FillType	2	is enclosed by a zero sum of Contour Directions
SkPath::kInverseEvenOdd_FillType	3	is enclosed by an even number of Contours

Example

See Also

SkPaint::Style Direction getFillType setFillType

---

FillType getFillType() const

Returns FillType, the rule used to fill Path. FillType of a new Path is kWinding FillType.

Return Value

one of: kWinding FillType, kEvenOdd FillType, kInverseWinding FillType, kInverseEvenOdd FillType

Example

Example Output

default path fill type is kWinding_FillType

See Also

FillType setFillType isInverseFillType

---

void setFillType(FillType ft)

Sets FillType, the rule used to fill Path. While there is no check that ft is legal, values outside of FillType are not supported.

Parameters

ft	one of: kWinding FillType, kEvenOdd FillType, kInverseWinding FillType, kInverseEvenOdd FillType

Example

If empty Path is set to inverse FillType, it fills all pixels.

See Also

FillType getFillType toggleInverseFillType

---

bool isInverseFillType() const

Returns if FillType describes area outside Path geometry. The inverse fill area extends indefinitely.

Return Value

true if FillType is kInverseWinding FillType or kInverseEvenOdd FillType

Example

Example Output

default path fill type is inverse: false

See Also

FillType getFillType setFillType toggleInverseFillType

---

void toggleInverseFillType()

Replaces FillType with its inverse. The inverse of FillType describes the area unmodified by the original FillType.

FillType	toggled FillType
kWinding FillType	kInverseWinding FillType
kEvenOdd FillType	kInverseEvenOdd FillType
kInverseWinding FillType	kWinding FillType
kInverseEvenOdd FillType	kEvenOdd FillType

Example

Path drawn normally and through its inverse touches every pixel once.

See Also

FillType getFillType setFillType isInverseFillType

---

    enum Convexity : uint8_t {
        kUnknown_Convexity,
        kConvex_Convexity,
        kConcave_Convexity,
    };

Path is convex if it contains one Contour and Contour loops no more than 360 degrees, and Contour angles all have same Direction. Convex Path may have better performance and require fewer resources on GPU Surface.

Path is concave when either at least one Direction change is clockwise and another is counterclockwise, or the sum of the changes in Direction is not 360 degrees.

Initially Path Convexity is kUnknown Convexity. Path Convexity is computed if needed by destination Surface.

Constants

Const	Value	Description
SkPath::kUnknown_Convexity	0	indicates Convexity has not been determined
SkPath::kConvex_Convexity	1	one Contour made of a simple geometry without indentations
SkPath::kConcave_Convexity	2	more than one Contour, or a geometry with indentations

Example

See Also

Contour Direction getConvexity getConvexityOrUnknown setConvexity isConvex

---

Convexity getConvexity() const

Computes Convexity if required, and returns stored value. Convexity is computed if stored value is kUnknown Convexity, or if Path has been altered since Convexity was computed or set.

Return Value

computed or stored Convexity

Example

See Also

Convexity Contour Direction getConvexityOrUnknown setConvexity isConvex

---

Convexity getConvexityOrUnknown() const

Returns last computed Convexity, or kUnknown Convexity if Path has been altered since Convexity was computed or set.

Return Value

stored Convexity

Example

Convexity is unknown unless getConvexity is called without a subsequent call that alters the path.

See Also

Convexity Contour Direction getConvexity setConvexity isConvex

---

void setConvexity(Convexity convexity)

Stores convexity so that it is later returned by getConvexity or getConvexityOrUnknown. convexity may differ from getConvexity, although setting an incorrect value may cause incorrect or inefficient drawing.

If convexity is kUnknown Convexity: getConvexity will compute Convexity, and getConvexityOrUnknown will return kUnknown Convexity.

If convexity is kConvex Convexity or kConcave Convexity, getConvexity and getConvexityOrUnknown will return convexity until the path is altered.

Parameters

convexity

one of: kUnknown Convexity, kConvex Convexity, or kConcave Convexity

Example

See Also

Convexity Contour Direction getConvexity getConvexityOrUnknown isConvex

---

bool isConvex() const

Computes Convexity if required, and returns true if value is kConvex Convexity. If setConvexity was called with kConvex Convexity or kConcave Convexity, and the path has not been altered, Convexity is not recomputed.

Return Value

true if Convexity stored or computed is kConvex Convexity

Example

Concave shape is erroneously considered convex after a forced call to setConvexity.

See Also

Convexity Contour Direction getConvexity getConvexityOrUnknown setConvexity

---

bool isOval(SkRect* bounds) const

Returns true if this path is recognized as an oval or circle.

bounds receives bounds of Oval.

bounds is unmodified if Oval is not found.

Parameters

bounds

storage for bounding Rect of Oval; may be nullptr

Return Value

true if Path is recognized as an oval or circle

Example

See Also

Oval addCircle addOval^[2]

---

bool isRRect(SkRRect* rrect) const

Returns true if this path is recognized as a SkRRect (but not an oval/circle or rect).

rrect receives bounds of Round Rect.

rrect is unmodified if Round Rect is not found.

Parameters

rrect

storage for bounding Rect of Round Rect; may be nullptr

Return Value

true if Path contains only Round Rect

Example

Draw rounded rectangle and its bounds.

See Also

Round Rect addRoundRect^[2] addRRect^[2]

---

SkPath& reset()

Sets Path to its initial state. Removes Verb Array, Point Array, and Weights, and sets FillType to kWinding FillType. Internal storage associated with Path is released.

Return Value

reference to Path

Example

See Also

rewind()

---

SkPath& rewind()

Sets Path to its initial state, preserving internal storage. Removes Verb Array, Point Array, and Weights, and sets FillType to kWinding FillType. Internal storage associated with Path is retained.

Use rewind() instead of reset() if Path storage will be reused and performance is critical.

Return Value

reference to Path

Example

Although path1 retains its internal storage, it is indistinguishable from a newly initialized path.

See Also

reset()

---

bool isEmpty() const

Returns if Path is empty. Empty Path may have FillType but has no SkPoint, Verb, or Conic Weight. SkPath() constructs empty Path; reset() and rewind() make Path empty.

Return Value

true if the path contains no Verb array

Example

Example Output

initial path is empty
after moveTo path is not empty
after rewind path is empty
after lineTo path is not empty
after reset path is empty

See Also

SkPath() reset() rewind()

---

bool isLastContourClosed() const

Returns if Contour is closed. Contour is closed if Path Verb array was last modified by close(). When stroked, closed Contour draws Paint Stroke Join instead of Paint Stroke Cap at first and last Point.

Return Value

true if the last Contour ends with a kClose Verb

Example

close() has no effect if Path is empty; isLastContourClosed() returns false until Path has geometry followed by close().

Example Output

initial last contour is not closed
after close last contour is not closed
after lineTo last contour is not closed
after close last contour is closed

See Also

close()

---

bool isFinite() const

Returns true for finite Point array values between negative SK ScalarMax and positive SK ScalarMax. Returns false for any Point array value of SK ScalarInfinity, SK ScalarNegativeInfinity, or SK ScalarNaN.

Return Value

true if all Point values are finite

Example

Example Output

initial path is finite
after line path is finite
after scale path is not finite

See Also

SkScalar

---

bool isVolatile() const

Returns true if the path is volatile; it will not be altered or discarded by the caller after it is drawn. Paths by default have volatile set false, allowing Surface to attach a cache of data which speeds repeated drawing. If true, Surface may not speed repeated drawing.

Return Value

true if caller will alter Path after drawing

Example

Example Output

volatile by default is false

See Also

setIsVolatile

---

void setIsVolatile(bool isVolatile)

Specifies whether Path is volatile; whether it will be altered or discarded by the caller after it is drawn. Paths by default have volatile set false, allowing Device to attach a cache of data which speeds repeated drawing.

Mark temporary paths, discarded or modified after use, as volatile to inform Device that the path need not be cached.

Mark animating Path volatile to improve performance. Mark unchanging Path non-volatile to improve repeated rendering.

Raster Surface Path draws are affected by volatile for some shadows. GPU Surface Path draws are affected by volatile for some shadows and concave geometries.

Parameters

isVolatile

true if caller will alter Path after drawing

Example

See Also

isVolatile

---

static bool IsLineDegenerate(const SkPoint& p1, const SkPoint& p2, bool exact)

Tests if Line between Point pair is degenerate. Line with no length or that moves a very short distance is degenerate; it is treated as a point.

exact changes the equality test. If true, returns true only if p1 equals p2. If false, returns true if p1 equals or nearly equals p2.

Parameters

p1	line start point
p2	line end point
exact	if false, allow nearly equals

Return Value

true if Line is degenerate; its length is effectively zero

Example

As single precision floats, 100 and 100.000001 have the same bit representation, and are exactly equal. 100 and 100.0001 have different bit representations, and are not exactly equal, but are nearly equal.

Example Output

line from (100,100) to (100,100) is degenerate, nearly
line from (100,100) to (100,100) is degenerate, exactly
line from (100,100) to (100.0001,100.0001) is degenerate, nearly
line from (100,100) to (100.0001,100.0001) is not degenerate, exactly

See Also

IsQuadDegenerate IsCubicDegenerate

---

static bool IsQuadDegenerate(const SkPoint& p1, const SkPoint& p2, const SkPoint& p3, bool exact)

Tests if Quad is degenerate. Quad with no length or that moves a very short distance is degenerate; it is treated as a point.

Parameters

p1	Quad start point
p2	Quad control point
p3	Quad end point
exact	if true, returns true only if p1, p2, and p3 are equal; if false, returns true if p1, p2, and p3 are equal or nearly equal

Return Value

true if Quad is degenerate; its length is effectively zero

Example

As single precision floats: 100, 100.00001, and 100.00002 have different bit representations but nearly the same value. Translating all three by 1000 gives them the same bit representation; the fractional portion of the number can not be represented by the float and is lost.

Example Output

quad (100,100), (100.00001,100.00001), (100.00002,100.00002) is degenerate, nearly
quad (1100,1100), (1100,1100), (1100,1100) is degenerate, nearly
quad (100,100), (100.00001,100.00001), (100.00002,100.00002) is not degenerate, exactly
quad (1100,1100), (1100,1100), (1100,1100) is degenerate, exactly

See Also

IsLineDegenerate IsCubicDegenerate

---

static bool IsCubicDegenerate(const SkPoint& p1, const SkPoint& p2, const SkPoint& p3,
                              const SkPoint& p4, bool exact)

Tests if Cubic is degenerate. Cubic with no length or that moves a very short distance is degenerate; it is treated as a point.

Parameters

p1	Cubic start point
p2	Cubic control point 1
p3	Cubic control point 2
p4	Cubic end point
exact	if true, returns true only if p1, p2, p3, and p4 are equal; if false, returns true if p1, p2, p3, and p4 are equal or nearly equal

Return Value

true if Cubic is degenerate; its length is effectively zero

Example

Example Output

0.00024414062 is degenerate
0.00024414065 is length

---

bool isLine(SkPoint line[2]) const

Returns true if Path contains only one Line; Path Verb array has two entries: kMove Verb, kLine Verb. If Path contains one Line and line is not nullptr, line is set to Line start point and Line end point. Returns false if Path is not one Line; line is unaltered.

Parameters

line	storage for Line. May be nullptr

Return Value

true if Path contains exactly one Line

Example

Example Output

empty is not line
zero line is line (0,0) (0,0)
line is line (10,10) (20,20)
second move is not line

Point Array contains Points satisfying the allocated Points for each Verb in Verb Array. For instance, Path containing one Contour with Line and Quad is described by Verb Array: Verb::kMoveTo, Verb::kLineTo, Verb::kQuadTo; and one Point for move, one Point for Line, two Points for Quad; totaling four Points.

Point Array may be read directly from Path with getPoints, or inspected with getPoint, with Iter, or with RawIter.

---

int getPoints(SkPoint points[], int max) const

Returns number of points in Path. Up to max points are copied. points may be nullptr; then, max must be zero. If max is greater than number of points, excess points storage is unaltered.

Parameters

points	storage for Path Point array. May be nullptr
max	maximum to copy; must be greater than or equal to zero

Return Value

Path Point array length

Example

Example Output

no points point count: 3
zero max point count: 3
too small point count: 3  (0,0) (20,20)
just right point count: 3  (0,0) (20,20) (-10,-10)

See Also

countPoints getPoint

---

int countPoints() const

Returns the number of points in Path. Point count is initially zero.

Return Value

Path Point array length

Example

Example Output

empty point count: 0
zero line point count: 2
line point count: 2
second move point count: 3

See Also

getPoints

---

SkPoint getPoint(int index) const

Returns Point at index in Point Array. Valid range for index is 0 to countPoints - 1. Returns (0, 0) if index is out of range.

Parameters

index

Point array element selector

Return Value

Point array value or (0, 0)

Example

Example Output

point 0: (-10,-10)
point 1: (10,10)

See Also

countPoints getPoints

Verb Array always starts with kMove Verb. If kClose Verb is not the last entry, it is always followed by kMove Verb; the quantity of kMove Verb equals the Contour count. Verb Array does not include or count kDone Verb; it is a convenience returned when iterating through Verb Array.

Verb Array may be read directly from Path with getVerbs, or inspected with Iter, or with RawIter.

---

int countVerbs() const

Returns the number of Verbs: kMove Verb, kLine Verb, kQuad Verb, kConic Verb, kCubic Verb, and kClose Verb; added to Path.

Return Value

length of Verb Array

Example

Example Output

empty verb count: 0
round rect verb count: 10

See Also

getVerbs Iter RawIter

---

int getVerbs(uint8_t verbs[], int max) const

Returns the number of verbs in the path. Up to max verbs are copied. The verbs are copied as one byte per verb.

Parameters

verbs	storage for verbs, may be nullptr
max	maximum number to copy into verbs

Return Value

the actual number of verbs in the path

Example

Example Output

no verbs verb count: 3
zero max verb count: 3
too small verb count: 3  move line
just right verb count: 3  move line line

See Also

countVerbs getPoints Iter RawIter

---

void swap(SkPath& other)

Exchanges the Verb Array, Point Array, Weights, and Fill Type with other. Cached state is also exchanged. swap() internally exchanges pointers, so it is lightweight and does not allocate memory.

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

Parameters

other

Path exchanged by value

Example

Example Output

path1 bounds = 0, 0, 0, 0
path2 bounds = 10, 20, 30, 40

See Also

operator=(const SkPath& path)

---

const SkRect& getBounds() const

Returns minimum and maximum axes values of Point Array. Returns (0, 0, 0, 0) if Path contains no points. Returned bounds width and height may be larger or smaller than area affected when Path is drawn.

Rect returned includes all Points added to Path, including Points associated with kMove Verb that define empty Contours.

Return Value

bounds of all Points in Point Array

Example

Bounds of upright Circle can be predicted from center and radius. Bounds of rotated Circle includes control Points outside of filled area.

Example Output

empty bounds = 0, 0, 0, 0
circle bounds = 25, 20, 75, 70
rotated circle bounds = 14.6447, 9.64466, 85.3553, 80.3553

See Also

computeTightBounds updateBoundsCache

---

void updateBoundsCache() const

Updates internal bounds so that subsequent calls to getBounds are instantaneous. Unaltered copies of Path may also access cached bounds through getBounds.

For now, identical to calling getBounds and ignoring the returned value.

Call to prepare Path subsequently drawn from multiple threads, to avoid a race condition where each draw separately computes the bounds.

Example

Example Output

#Volatile
uncached avg: 0.18048 ms
cached avg: 0.182784 ms

See Also

getBounds

---

SkRect computeTightBounds() const

Returns minimum and maximum axes values of the lines and curves in Path. Returns (0, 0, 0, 0) if Path contains no points. Returned bounds width and height may be larger or smaller than area affected when Path is drawn.

Includes Points associated with kMove Verb that define empty Contours.

Behaves identically to getBounds when Path contains only lines. If Path contains curves, computed bounds includes the maximum extent of the Quad, Conic, or Cubic; is slower than getBounds; and unlike getBounds, does not cache the result.

Return Value

tight bounds of curves in Path

Example

Example Output

empty bounds = 0, 0, 0, 0
circle bounds = 25, 20, 75, 70
rotated circle bounds = 25, 20, 75, 70

See Also

getBounds

---

bool conservativelyContainsRect(const SkRect& rect) const

Returns true if rect is contained by Path. May return false when rect is contained by Path.

For now, only returns true if Path has one Contour and is convex. rect may share points and edges with Path and be contained. Returns true if rect is empty, that is, it has zero width or height; and the Point or Line described by rect is contained by Path.

Parameters

rect	Rect, Line, or Point checked for containment

Return Value

true if rect is contained

Example

Rect is drawn in blue if it is contained by red Path.

See Also

contains Op Rect Convexity

---

void incReserve(int extraPtCount)

Grows Path Verb Array and Point Array to contain extraPtCount additional Points. May improve performance and use less memory by reducing the number and size of allocations when creating Path.

Parameters

extraPtCount

number of additional Points to allocate

Example

See Also

Point Array

---

void shrinkToFit()

Shrinks Path Verb Array and Point Array storage to discard unused capacity. May reduce the heap overhead for Paths known to be fully constructed.

See Also

incReserve

---

SkPath& moveTo(SkScalar x, SkScalar y)

Adds beginning of Contour at Point (x, y).

Parameters

x	x-axis value of Contour start
y	y-axis value of Contour start

Return Value

reference to Path

Example

See Also

Contour lineTo^[2] rMoveTo quadTo^[2] conicTo^[2] cubicTo^[2] close()

---

SkPath& moveTo(const SkPoint& p)

Adds beginning of Contour at Point p.

Parameters

p	contour start

Return Value

reference to Path

Example

See Also

Contour lineTo^[2] rMoveTo quadTo^[2] conicTo^[2] cubicTo^[2] close()

---

SkPath& rMoveTo(SkScalar dx, SkScalar dy)

Adds beginning of Contour relative to Last Point. If Path is empty, starts Contour at (dx, dy). Otherwise, start Contour at Last Point offset by (dx, dy). Function name stands for "relative move to".

Parameters

dx	offset from Last Point to Contour start on x-axis
dy	offset from Last Point to Contour start on y-axis

Return Value

reference to Path

Example

See Also

Contour lineTo^[2] moveTo^[2] quadTo^[2] conicTo^[2] cubicTo^[2] close()

---

SkPath& lineTo(SkScalar x, SkScalar y)

Adds Line from Last Point to (x, y). If Path is empty, or last Verb is kClose Verb, Last Point is set to (0, 0) before adding Line.

lineTo appends kMove Verb to Verb Array and (0, 0) to Point Array, if needed. lineTo then appends kLine Verb to Verb Array and (x, y) to Point Array.

Parameters

x	end of added Line in x
y	end of added Line in y

Return Value

reference to Path

Example

See Also

Contour moveTo^[2] rLineTo addRect^[2][3]

---

SkPath& lineTo(const SkPoint& p)

Adds Line from Last Point to Point p. If Path is empty, or last Verb is kClose Verb, Last Point is set to (0, 0) before adding Line.

lineTo first appends kMove Verb to Verb Array and (0, 0) to Point Array, if needed. lineTo then appends kLine Verb to Verb Array and Point p to Point Array.

Parameters

p	end Point of added Line

Return Value

reference to Path

Example

See Also

Contour moveTo^[2] rLineTo addRect^[2][3]

---

SkPath& rLineTo(SkScalar dx, SkScalar dy)

Adds Line from Last Point to Vector (dx, dy). If Path is empty, or last Verb is kClose Verb, Last Point is set to (0, 0) before adding Line.

Appends kMove Verb to Verb Array and (0, 0) to Point Array, if needed; then appends kLine Verb to Verb Array and Line end to Point Array. Line end is Last Point plus Vector (dx, dy). Function name stands for "relative line to".

Parameters

dx	offset from Last Point to Line end on x-axis
dy	offset from Last Point to Line end on y-axis

Return Value

reference to Path

Example

See Also

Contour moveTo^[2] lineTo^[2] addRect^[2][3]

---

Quad describes a quadratic Bezier, a second-order curve identical to a section of a parabola. Quad begins at a start Point, curves towards a control Point, and then curves to an end Point.

Example

Quad is a special case of Conic where Conic Weight is set to one.

Quad is always contained by the triangle connecting its three Points. Quad begins tangent to the line between start Point and control Point, and ends tangent to the line between control Point and end Point.

Example

---

SkPath& quadTo(SkScalar x1, SkScalar y1, SkScalar x2, SkScalar y2)

Adds Quad from Last Point towards (x1, y1), to (x2, y2). If Path is empty, or last Verb is kClose Verb, Last Point is set to (0, 0) before adding Quad.

Appends kMove Verb to Verb Array and (0, 0) to Point Array, if needed; then appends kQuad Verb to Verb Array; and (x1, y1), (x2, y2) to Point Array.

Parameters

x1	control Point of Quad in x
y1	control Point of Quad in y
x2	end Point of Quad in x
y2	end Point of Quad in y

Return Value

reference to Path

Example

See Also

Contour moveTo^[2] conicTo^[2] rQuadTo

---

SkPath& quadTo(const SkPoint& p1, const SkPoint& p2)

Adds Quad from Last Point towards Point p1, to Point p2. If Path is empty, or last Verb is kClose Verb, Last Point is set to (0, 0) before adding Quad.

Appends kMove Verb to Verb Array and (0, 0) to Point Array, if needed; then appends kQuad Verb to Verb Array; and Points p1, p2 to Point Array.

Parameters

p1	control Point of added Quad
p2	end Point of added Quad

Return Value

reference to Path

Example

See Also

Contour moveTo^[2] conicTo^[2] rQuadTo

---

SkPath& rQuadTo(SkScalar dx1, SkScalar dy1, SkScalar dx2, SkScalar dy2)

Adds Quad from Last Point towards Vector (dx1, dy1), to Vector (dx2, dy2). If Path is empty, or last Verb is kClose Verb, Last Point is set to (0, 0) before adding Quad.

Appends kMove Verb to Verb Array and (0, 0) to Point Array, if needed; then appends kQuad Verb to Verb Array; and appends Quad control and Quad end to Point Array. Quad control is Last Point plus Vector (dx1, dy1). Quad end is Last Point plus Vector (dx2, dy2). Function name stands for "relative quad to".

Parameters

dx1	offset from Last Point to Quad control on x-axis
dy1	offset from Last Point to Quad control on y-axis
dx2	offset from Last Point to Quad end on x-axis
dy2	offset from Last Point to Quad end on y-axis

Return Value

reference to Path

Example

See Also

Contour moveTo^[2] conicTo^[2] quadTo^[2]

Conic describes a conical section: a piece of an ellipse, or a piece of a parabola, or a piece of a hyperbola. Conic begins at a start Point, curves towards a control Point, and then curves to an end Point. The influence of the control Point is determined by Conic Weight.

Each Conic in Path adds two Points and one Conic Weight. Conic Weights in Path may be inspected with Iter, or with RawIter.

---

Weight determines both the strength of the control Point and the type of Conic. Weight varies from zero to infinity. At zero, Weight causes the control Point to have no effect; Conic is identical to a line segment from start Point to end point. If Weight is less than one, Conic follows an elliptical arc. If Weight is exactly one, then Conic is identical to Quad; Conic follows a parabolic arc. If Weight is greater than one, Conic follows a hyperbolic arc. If Weight is infinity, Conic is identical to two line segments, connecting start Point to control Point, and control Point to end Point.

Example

When Conic Weight is one, Quad is added to path; the two are identical.

Example Output

move {0, 0},
quad {0, 0}, {20, 30}, {50, 60},
done

If weight is less than one, Conic is an elliptical segment.

Example

A 90 degree circular arc has the weight 1 / sqrt(2).

Example Output

move {0, 0},
conic {0, 0}, {20, 0}, {20, 20}, weight = 0.707107
done

If weight is greater than one, Conic is a hyperbolic segment. As weight gets large, a hyperbolic segment can be approximated by straight lines connecting the control Point with the end Points.

Example

Example Output

move {0, 0},
line {0, 0}, {20, 0},
line {20, 0}, {20, 20},
done

---

SkPath& conicTo(SkScalar x1, SkScalar y1, SkScalar x2, SkScalar y2, SkScalar w)

Adds Conic from Last Point towards (x1, y1), to (x2, y2), weighted by w. If Path is empty, or last Verb is kClose Verb, Last Point is set to (0, 0) before adding Conic.

Appends kMove Verb to Verb Array and (0, 0) to Point Array, if needed.

If w is finite and not one, appends kConic Verb to Verb Array; and (x1, y1), (x2, y2) to Point Array; and w to Conic Weights.

If w is one, appends kQuad Verb to Verb Array, and (x1, y1), (x2, y2) to Point Array.

If w is not finite, appends kLine Verb twice to Verb Array, and (x1, y1), (x2, y2) to Point Array.

Parameters

x1	control Point of Conic in x
y1	control Point of Conic in y
x2	end Point of Conic in x
y2	end Point of Conic in y
w	weight of added Conic

Return Value

reference to Path

Example

As weight increases, curve is pulled towards control point. The bottom two curves are elliptical; the next is parabolic; the top curve is hyperbolic.

See Also

rConicTo arcTo^[2][3][4][5] addArc quadTo^[2]

---

SkPath& conicTo(const SkPoint& p1, const SkPoint& p2, SkScalar w)

Adds Conic from Last Point towards Point p1, to Point p2, weighted by w. If Path is empty, or last Verb is kClose Verb, Last Point is set to (0, 0) before adding Conic.

Appends kMove Verb to Verb Array and (0, 0) to Point Array, if needed.

If w is finite and not one, appends kConic Verb to Verb Array; and Points p1, p2 to Point Array; and w to Conic Weights.

If w is one, appends kQuad Verb to Verb Array, and Points p1, p2 to Point Array.

If w is not finite, appends kLine Verb twice to Verb Array, and Points p1, p2 to Point Array.

Parameters

p1	control Point of added Conic
p2	end Point of added Conic
w	weight of added Conic

Return Value

reference to Path

Example

Conics and arcs use identical representations. As the arc sweep increases the Conic Weight also increases, but remains smaller than one.

See Also

rConicTo arcTo^[2][3][4][5] addArc quadTo^[2]

---

SkPath& rConicTo(SkScalar dx1, SkScalar dy1, SkScalar dx2, SkScalar dy2, SkScalar w)

Adds Conic from Last Point towards Vector (dx1, dy1), to Vector (dx2, dy2), weighted by w. If Path is empty, or last Verb is kClose Verb, Last Point is set to (0, 0) before adding Conic.

Appends kMove Verb to Verb Array and (0, 0) to Point Array, if needed.

If w is finite and not one, next appends kConic Verb to Verb Array, and w is recorded as Conic Weight; otherwise, if w is one, appends kQuad Verb to Verb Array; or if w is not finite, appends kLine Verb twice to Verb Array.

In all cases appends Points control and end to Point Array. control is Last Point plus Vector (dx1, dy1). end is Last Point plus Vector (dx2, dy2).

Function name stands for "relative conic to".

Parameters

dx1	offset from Last Point to Conic control on x-axis
dy1	offset from Last Point to Conic control on y-axis
dx2	offset from Last Point to Conic end on x-axis
dy2	offset from Last Point to Conic end on y-axis
w	weight of added Conic

Return Value

reference to Path

Example

See Also

conicTo^[2] arcTo^[2][3][4][5] addArc quadTo^[2]

---

Cubic describes a Bezier Curve segment described by a third-order polynomial. Cubic begins at a start Point, curving towards the first control Point; and curves from the end Point towards the second control Point.

Example

---

SkPath& cubicTo(SkScalar x1, SkScalar y1, SkScalar x2, SkScalar y2, SkScalar x3, SkScalar y3)

Adds Cubic from Last Point towards (x1, y1), then towards (x2, y2), ending at (x3, y3). If Path is empty, or last Verb is kClose Verb, Last Point is set to (0, 0) before adding Cubic.

Appends kMove Verb to Verb Array and (0, 0) to Point Array, if needed; then appends kCubic Verb to Verb Array; and (x1, y1), (x2, y2), (x3, y3) to Point Array.

Parameters

x1	first control Point of Cubic in x
y1	first control Point of Cubic in y
x2	second control Point of Cubic in x
y2	second control Point of Cubic in y
x3	end Point of Cubic in x
y3	end Point of Cubic in y

Return Value

reference to Path

Example

See Also

Contour moveTo^[2] rCubicTo quadTo^[2]

---

SkPath& cubicTo(const SkPoint& p1, const SkPoint& p2, const SkPoint& p3)

Adds Cubic from Last Point towards Point p1, then towards Point p2, ending at Point p3. If Path is empty, or last Verb is kClose Verb, Last Point is set to (0, 0) before adding Cubic.

Appends kMove Verb to Verb Array and (0, 0) to Point Array, if needed; then appends kCubic Verb to Verb Array; and Points p1, p2, p3 to Point Array.

Parameters

p1	first control Point of Cubic
p2	second control Point of Cubic
p3	end Point of Cubic

Return Value

reference to Path

Example

See Also

Contour moveTo^[2] rCubicTo quadTo^[2]

---

SkPath& rCubicTo(SkScalar x1, SkScalar y1, SkScalar x2, SkScalar y2, SkScalar x3, SkScalar y3)

Adds Cubic from Last Point towards Vector (dx1, dy1), then towards Vector (dx2, dy2), to Vector (dx3, dy3). If Path is empty, or last Verb is kClose Verb, Last Point is set to (0, 0) before adding Cubic.

Appends kMove Verb to Verb Array and (0, 0) to Point Array, if needed; then appends kCubic Verb to Verb Array; and appends Cubic control and Cubic end to Point Array. Cubic control is Last Point plus Vector (dx1, dy1). Cubic end is Last Point plus Vector (dx2, dy2). Function name stands for "relative cubic to".

Parameters

x1	offset from Last Point to first Cubic control on x-axis
y1	offset from Last Point to first Cubic control on y-axis
x2	offset from Last Point to second Cubic control on x-axis
y2	offset from Last Point to second Cubic control on y-axis
x3	offset from Last Point to Cubic end on x-axis
y3	offset from Last Point to Cubic end on y-axis

Return Value

reference to Path

Example

See Also

Contour moveTo^[2] cubicTo^[2] quadTo^[2]

---

Arc can be constructed in a number of ways. Arc may be described by part of Oval and angles, by start point and end point, and by radius and tangent lines. Each construction has advantages, and some constructions correspond to Arc drawing in graphics standards.

All Arc draws are implemented by one or more Conic draws. When Conic Weight is less than one, Conic describes an Arc of some Oval or Circle.

arcTo(const SkRect& oval, SkScalar startAngle, SkScalar sweepAngle, bool forceMoveTo) describes Arc as a piece of Oval, beginning at start angle, sweeping clockwise or counterclockwise, which may continue Contour or start a new one. This construction is similar to PostScript and HTML Canvas arcs. Variation addArc always starts new Contour. Canvas::drawArc draws without requiring Path.

arcTo(SkScalar x1, SkScalar y1, SkScalar x2, SkScalar y2, SkScalar radius) describes Arc as tangent to the line (x0, y0), (x1, y1) and tangent to the line (x1, y1), (x2, y2) where (x0, y0) is the last Point added to Path. This construction is similar to PostScript and HTML Canvas arcs.

arcTo(SkScalar rx, SkScalar ry, SkScalar xAxisRotate, ArcSize largeArc, Direction sweep, SkScalar x, SkScalar y) describes Arc as part of Oval with radii (rx, ry), beginning at last Point added to Path and ending at (x, y). More than one Arc satisfies this criteria, so additional values choose a single solution. This construction is similar to SVG arcs.

conicTo describes Arc of less than 180 degrees as a pair of tangent lines and Conic Weight. conicTo can represent any Arc with a sweep less than 180 degrees at any rotation. All arcTo constructions are converted to Conic data when added to Path.

1 arcTo(const SkRect& oval, SkScalar startAngle, SkScalar sweepAngle, bool forceMoveTo)

2 parameter sets force MoveTo

3 start angle must be multiple of 90 degrees

4 arcTo(SkScalar x1, SkScalar y1, SkScalar x2, SkScalar y2, SkScalar radius)

5 arcTo(SkScalar rx, SkScalar ry, SkScalar xAxisRotate, ArcSize largeArc, Direction sweep, SkScalar x, SkScalar y)

Example

In the example above:

1 describes an arc from an oval, a starting angle, and a sweep angle.

2 is similar to 1, but does not require building a path to draw.

3 is similar to 1, but always begins new Contour.

4 describes an arc from a pair of tangent lines and a radius.

5 describes an arc from Oval center, arc start Point and arc end Point.

6 describes an arc from a pair of tangent lines and a Conic Weight.

---

SkPath& arcTo(const SkRect& oval, SkScalar startAngle, SkScalar sweepAngle, bool forceMoveTo)

Appends Arc to Path. Arc added is part of ellipse bounded by oval, from startAngle through sweepAngle. Both startAngle and sweepAngle are measured in degrees, where zero degrees is aligned with the positive x-axis, and positive sweeps extends Arc clockwise.

arcTo adds Line connecting Path last Point to initial Arc Point if forceMoveTo is false and Path is not empty. Otherwise, added Contour begins with first point of Arc. Angles greater than -360 and less than 360 are treated modulo 360.

Parameters

oval	bounds of ellipse containing Arc
startAngle	starting angle of Arc in degrees
sweepAngle	sweep, in degrees. Positive is clockwise; treated modulo 360
forceMoveTo	true to start a new contour with Arc

Return Value

reference to Path

Example

arcTo continues a previous contour when forceMoveTo is false and when Path is not empty.

See Also

addArc SkCanvas::drawArc conicTo^[2]

---

SkPath& arcTo(SkScalar x1, SkScalar y1, SkScalar x2, SkScalar y2, SkScalar radius)

Appends Arc to Path, after appending Line if needed. Arc is implemented by Conic weighted to describe part of Circle. Arc is contained by tangent from last Path point (x0, y0) to (x1, y1), and tangent from (x1, y1) to (x2, y2). Arc is part of Circle sized to radius, positioned so it touches both tangent lines.

Example

If last Path Point does not start Arc, arcTo appends connecting Line to Path. The length of Vector from (x1, y1) to (x2, y2) does not affect Arc.

Example

Arc sweep is always less than 180 degrees. If radius is zero, or if tangents are nearly parallel, arcTo appends Line from last Path Point to (x1, y1).

arcTo appends at most one Line and one Conic. arcTo implements the functionality of PostScript Arct and HTML Canvas ArcTo.

Parameters

x1	x-axis value common to pair of tangents
y1	y-axis value common to pair of tangents
x2	x-axis value end of second tangent
y2	y-axis value end of second tangent
radius	distance from Arc to Circle center

Return Value

reference to Path

Example

arcTo is represented by Line and circular Conic in Path.

Example Output

move to (156,20)
line (156,20),(79.2893,20)
conic (79.2893,20),(200,20),(114.645,105.355) weight 0.382683

See Also

conicTo^[2]

---

SkPath& arcTo(const SkPoint p1, const SkPoint p2, SkScalar radius)

Appends Arc to Path, after appending Line if needed. Arc is implemented by Conic weighted to describe part of Circle. Arc is contained by tangent from last Path point to p1, and tangent from p1 to p2. Arc is part of Circle sized to radius, positioned so it touches both tangent lines.

If last Path Point does not start Arc, arcTo appends connecting Line to Path. The length of Vector from p1 to p2 does not affect Arc.

Arc sweep is always less than 180 degrees. If radius is zero, or if tangents are nearly parallel, arcTo appends Line from last Path Point to p1.

arcTo appends at most one Line and one Conic. arcTo implements the functionality of PostScript Arct and HTML Canvas ArcTo.

Parameters

p1	Point common to pair of tangents
p2	end of second tangent
radius	distance from Arc to Circle center

Return Value

reference to Path

Example

Because tangent lines are parallel, arcTo appends line from last Path Point to p1, but does not append a circular Conic.

Example Output

move to (156,20)
line (156,20),(200,20)

See Also

conicTo^[2]

---

    enum ArcSize {
        kSmall_ArcSize,
        kLarge_ArcSize,
    };

Four Oval parts with radii (rx, ry) start at last Path Point and ends at (x, y). ArcSize and Direction select one of the four Oval parts.

Constants

Const	Value	Description
SkPath::kSmall_ArcSize	0	smaller of Arc pair
SkPath::kLarge_ArcSize	1	larger of Arc pair

Example

Arc begins at top of Oval pair and ends at bottom. Arc can take four routes to get there. Two routes are large, and two routes are counterclockwise. The one route both large and counterclockwise is blue.

See Also

arcTo^[2][3][4][5] Direction

---

SkPath& arcTo(SkScalar rx, SkScalar ry, SkScalar xAxisRotate, ArcSize largeArc, Direction sweep,
              SkScalar x, SkScalar y)

Appends Arc to Path. Arc is implemented by one or more Conics weighted to describe part of Oval with radii (rx, ry) rotated by xAxisRotate degrees. Arc curves from last Path Point to (x, y), choosing one of four possible routes: clockwise or counterclockwise, and smaller or larger.

Arc sweep is always less than 360 degrees. arcTo appends Line to (x, y) if either radii are zero, or if last Path Point equals (x, y). arcTo scales radii (rx, ry) to fit last Path Point and (x, y) if both are greater than zero but too small.

arcTo appends up to four Conic curves. arcTo implements the functionality of SVG Arc, although SVG "sweep-flag" value is opposite the integer value of sweep; SVG "sweep-flag" uses 1 for clockwise, while kCW Direction cast to int is zero.

Parameters

rx	radius in x before x-axis rotation
ry	radius in y before x-axis rotation
xAxisRotate	x-axis rotation in degrees; positive values are clockwise
largeArc	chooses smaller or larger Arc
sweep	chooses clockwise or counterclockwise Arc
x	end of Arc
y	end of Arc

Return Value

reference to Path

Example

See Also

rArcTo ArcSize Direction

---

SkPath& arcTo(const SkPoint r, SkScalar xAxisRotate, ArcSize largeArc, Direction sweep,
              const SkPoint xy)

Appends Arc to Path. Arc is implemented by one or more Conic weighted to describe part of Oval with radii (r.fX, r.fY) rotated by xAxisRotate degrees. Arc curves from last Path Point to (xy.fX, xy.fY), choosing one of four possible routes: clockwise or counterclockwise, and smaller or larger.

Arc sweep is always less than 360 degrees. arcTo appends Line to xy if either radii are zero, or if last Path Point equals (x, y). arcTo scales radii r to fit last Path Point and xy if both are greater than zero but too small to describe an arc.

arcTo appends up to four Conic curves. arcTo implements the functionality of SVG Arc, although SVG "sweep-flag" value is opposite the integer value of sweep; SVG "sweep-flag" uses 1 for clockwise, while kCW Direction cast to int is zero.

Parameters

r	radii on axes before x-axis rotation
xAxisRotate	x-axis rotation in degrees; positive values are clockwise
largeArc	chooses smaller or larger Arc
sweep	chooses clockwise or counterclockwise Arc
xy	end of Arc

Return Value

reference to Path

Example

See Also

rArcTo ArcSize Direction

---

SkPath& rArcTo(SkScalar rx, SkScalar ry, SkScalar xAxisRotate, ArcSize largeArc, Direction sweep,
               SkScalar dx, SkScalar dy)

Appends Arc to Path, relative to last Path Point. Arc is implemented by one or more Conic, weighted to describe part of Oval with radii (rx, ry) rotated by xAxisRotate degrees. Arc curves from last Path Point (x0, y0) to end Point: (x0 + dx, y0 + dy), choosing one of four possible routes: clockwise or counterclockwise, and smaller or larger. If Path is empty, the start Arc Point is (0, 0).

Arc sweep is always less than 360 degrees. arcTo appends Line to end Point if either radii are zero, or if last Path Point equals end Point. arcTo scales radii (rx, ry) to fit last Path Point and end Point if both are greater than zero but too small to describe an arc.

arcTo appends up to four Conic curves. arcTo implements the functionality of SVG Arc, although SVG "sweep-flag" value is opposite the integer value of sweep; SVG "sweep-flag" uses 1 for clockwise, while kCW Direction cast to int is zero.

Parameters

rx	radius before x-axis rotation
ry	radius before x-axis rotation
xAxisRotate	x-axis rotation in degrees; positive values are clockwise
largeArc	chooses smaller or larger Arc
sweep	chooses clockwise or counterclockwise Arc
dx	x-axis offset end of Arc from last Path Point
dy	y-axis offset end of Arc from last Path Point

Return Value

reference to Path

Example

See Also

arcTo^[2][3][4][5] ArcSize Direction

---

SkPath& close()

Appends kClose Verb to Path. A closed Contour connects the first and last Point with Line, forming a continuous loop. Open and closed Contour draw the same with SkPaint::kFill Style. With SkPaint::kStroke Style, open Contour draws Paint Stroke Cap at Contour start and end; closed Contour draws Paint Stroke Join at Contour start and end.

close() has no effect if Path is empty or last Path Verb is kClose Verb.

Return Value

reference to Path

Example

See Also

---

static bool IsInverseFillType(FillType fill)

Returns true if fill is inverted and Path with fill represents area outside of its geometric bounds.

FillType	is inverse
kWinding FillType	false
kEvenOdd FillType	false
kInverseWinding FillType	true
kInverseEvenOdd FillType	true

Parameters

fill	one of: kWinding FillType, kEvenOdd FillType, kInverseWinding FillType, kInverseEvenOdd FillType

Return Value

true if Path fills outside its bounds

Example

Example Output

IsInverseFillType(kWinding_FillType) == false
IsInverseFillType(kEvenOdd_FillType) == false
IsInverseFillType(kInverseWinding_FillType) == true
IsInverseFillType(kInverseEvenOdd_FillType) == true

See Also

FillType getFillType setFillType ConvertToNonInverseFillType

---

static FillType ConvertToNonInverseFillType(FillType fill)

Returns equivalent Fill Type representing Path fill inside its bounds. .

FillType	inside FillType
kWinding FillType	kWinding FillType
kEvenOdd FillType	kEvenOdd FillType
kInverseWinding FillType	kWinding FillType
kInverseEvenOdd FillType	kEvenOdd FillType

Parameters

fill	one of: kWinding FillType, kEvenOdd FillType, kInverseWinding FillType, kInverseEvenOdd FillType

Return Value

fill, or kWinding FillType or kEvenOdd FillType if fill is inverted

Example

Example Output

ConvertToNonInverseFillType(kWinding_FillType) == kWinding_FillType
ConvertToNonInverseFillType(kEvenOdd_FillType) == kEvenOdd_FillType
ConvertToNonInverseFillType(kInverseWinding_FillType) == kWinding_FillType
ConvertToNonInverseFillType(kInverseEvenOdd_FillType) == kEvenOdd_FillType

See Also

FillType getFillType setFillType IsInverseFillType

---

static int ConvertConicToQuads(const SkPoint& p0, const SkPoint& p1, const SkPoint& p2, SkScalar w,
                               SkPoint pts[], int pow2)

Approximates Conic with Quad array. Conic is constructed from start Point p0, control Point p1, end Point p2, and weight w. Quad array is stored in pts; this storage is supplied by caller. Maximum Quad count is 2 to the pow2. Every third point in array shares last Point of previous Quad and first Point of next Quad. Maximum pts storage size is given by: (1 + 2 * (1 << pow2)) * sizeof(SkPoint).

Returns Quad count used the approximation, which may be smaller than the number requested.

Conic Weight determines the amount of influence Conic control point has on the curve. w less than one represents an elliptical section. w greater than one represents a hyperbolic section. w equal to one represents a parabolic section.

Two Quad curves are sufficient to approximate an elliptical Conic with a sweep of up to 90 degrees; in this case, set pow2 to one.

Parameters

p0	Conic start Point
p1	Conic control Point
p2	Conic end Point
w	Conic weight
pts	storage for Quad array
pow2	Quad count, as power of two, normally 0 to 5 (1 to 32 Quad curves)

Return Value

number of Quad curves written to pts

Example

A pair of Quad curves are drawn in red on top of the elliptical Conic curve in black. The middle curve is nearly circular. The top-right curve is parabolic, which can be drawn exactly with a single Quad.

See Also

Conic Quad

---

bool isRect(SkRect* rect, bool* isClosed = nullptr, Direction* direction = nullptr) const

Returns true if Path is equivalent to Rect when filled. If false: rect, isClosed, and direction are unchanged. If true: rect, isClosed, and direction are written to if not nullptr.

rect may be smaller than the Path bounds. Path bounds may include kMove Verb points that do not alter the area drawn by the returned rect.

Parameters

rect	storage for bounds of Rect; may be nullptr
isClosed	storage set to true if Path is closed; may be nullptr
direction	storage set to Rect direction; may be nullptr

Return Value

true if Path contains Rect

Example

After addRect, isRect returns true. Following moveTo permits isRect to return true, but following lineTo does not. addPoly returns true even though rect is not closed, and one side of rect is made up of consecutive line segments.

Example Output

empty is not rect
addRect is rect (10, 20, 30, 40); is closed; direction CW
moveTo is rect (10, 20, 30, 40); is closed; direction CW
lineTo is not rect
addPoly is rect (0, 0, 80, 80); is not closed; direction CCW

See Also

computeTightBounds conservativelyContainsRect getBounds isConvex isLastContourClosed isNestedFillRects

---

bool isNestedFillRects(SkRect rect[2], Direction dirs[2] = nullptr) const

Returns true if Path is equivalent to nested Rect pair when filled. If false, rect and dirs are unchanged. If true, rect and dirs are written to if not nullptr: setting rect[0] to outer Rect, and rect[1] to inner Rect; setting dirs[0] to Direction of outer Rect, and dirs[1] to Direction of inner Rect.

Parameters

rect	storage for Rect pair; may be nullptr
dirs	storage for Direction pair; may be nullptr

Return Value

true if Path contains nested Rect pair

Example

Example Output

outer (7.5, 17.5, 32.5, 42.5); direction CW
inner (12.5, 22.5, 27.5, 37.5); direction CCW

See Also

computeTightBounds conservativelyContainsRect getBounds isConvex isLastContourClosed isRect

---

SkPath& addRect(const SkRect& rect, Direction dir = kCW Direction)

Adds Rect to Path, appending kMove Verb, three kLine Verb, and kClose Verb, starting with top-left corner of Rect; followed by top-right, bottom-right, and bottom-left if dir is kCW Direction; or followed by bottom-left, bottom-right, and top-right if dir is kCCW Direction.

Parameters

rect	Rect to add as a closed contour
dir	Direction to wind added contour

Return Value

reference to Path

Example

The left Rect dashes starting at the top-left corner, to the right. The right Rect dashes starting at the top-left corner, towards the bottom.

See Also

SkCanvas::drawRect Direction

---

SkPath& addRect(const SkRect& rect, Direction dir, unsigned start)

Adds Rect to Path, appending kMove Verb, three kLine Verb, and kClose Verb. If dir is kCW Direction, Rect corners are added clockwise; if dir is kCCW Direction, Rect corners are added counterclockwise. start determines the first corner added.

start	first corner
0	top-left
1	top-right
2	bottom-right
3	bottom-left

Parameters

rect	Rect to add as a closed contour
dir	Direction to wind added contour
start	initial corner of Rect to add

Return Value

reference to Path

Example

The arrow is just after the initial corner and points towards the next corner appended to Path.

See Also

SkCanvas::drawRect Direction

---

SkPath& addRect(SkScalar left, SkScalar top, SkScalar right, SkScalar bottom,
                Direction dir = kCW Direction)

Adds Rect (left, top, right, bottom) to Path, appending kMove Verb, three kLine Verb, and kClose Verb, starting with top-left corner of Rect; followed by top-right, bottom-right, and bottom-left if dir is kCW Direction; or followed by bottom-left, bottom-right, and top-right if dir is kCCW Direction.

Parameters

left	smaller x-axis value of Rect
top	smaller y-axis value of Rect
right	larger x-axis value of Rect
bottom	larger y-axis value of Rect
dir	Direction to wind added contour

Return Value

reference to Path

Example

The left Rect dashes start at the top-left corner, and continue to the right. The right Rect dashes start at the top-left corner, and continue down.

See Also

SkCanvas::drawRect Direction

---

SkPath& addOval(const SkRect& oval, Direction dir = kCW Direction)

Adds Oval to path, appending kMove Verb, four kConic Verb, and kClose Verb. Oval is upright ellipse bounded by Rect oval with radii equal to half oval width and half oval height. Oval begins at (oval.fRight, oval.centerY()) and continues clockwise if dir is kCW Direction, counterclockwise if dir is kCCW Direction.

Parameters

oval	bounds of ellipse added
dir	Direction to wind ellipse

Return Value

reference to Path

Example

See Also

SkCanvas::drawOval Direction Oval

---

SkPath& addOval(const SkRect& oval, Direction dir, unsigned start)

Adds Oval to Path, appending kMove Verb, four kConic Verb, and kClose Verb. Oval is upright ellipse bounded by Rect oval with radii equal to half oval width and half oval height. Oval begins at start and continues clockwise if dir is kCW Direction, counterclockwise if dir is kCCW Direction.

start	Point
0	oval.centerX(), oval.fTop
1	oval.fRight, oval.centerY()
2	oval.centerX(), oval.fBottom
3	oval.fLeft, oval.centerY()

Parameters

oval	bounds of ellipse added
dir	Direction to wind ellipse
start	index of initial point of ellipse

Return Value

reference to Path

Example

See Also

SkCanvas::drawOval Direction Oval

---

SkPath& addCircle(SkScalar x, SkScalar y, SkScalar radius, Direction dir = kCW Direction)

Adds Circle centered at (x, y) of size radius to Path, appending kMove Verb, four kConic Verb, and kClose Verb. Circle begins at: (x + radius, y), continuing clockwise if dir is kCW Direction, and counterclockwise if dir is kCCW Direction.

Has no effect if radius is zero or negative.

Parameters

x	center of Circle
y	center of Circle
radius	distance from center to edge
dir	Direction to wind Circle

Return Value

reference to Path

Example

See Also

SkCanvas::drawCircle^[2] Direction Circle

---

SkPath& addArc(const SkRect& oval, SkScalar startAngle, SkScalar sweepAngle)

Appends Arc to Path, as the start of new Contour. Arc added is part of ellipse bounded by oval, from startAngle through sweepAngle. Both startAngle and sweepAngle are measured in degrees, where zero degrees is aligned with the positive x-axis, and positive sweeps extends Arc clockwise.

If sweepAngle <= -360, or sweepAngle >= 360; and startAngle modulo 90 is nearly zero, append Oval instead of Arc. Otherwise, sweepAngle values are treated modulo 360, and Arc may or may not draw depending on numeric rounding.

Parameters

oval	bounds of ellipse containing Arc
startAngle	starting angle of Arc in degrees
sweepAngle	sweep, in degrees. Positive is clockwise; treated modulo 360

Return Value

reference to Path

Example

The middle row of the left and right columns draw differently from the entries above and below because sweepAngle is outside of the range of +/-360, and startAngle modulo 90 is not zero.

See Also

Arc arcTo^[2][3][4][5] SkCanvas::drawArc

---

SkPath& addRoundRect(const SkRect& rect, SkScalar rx, SkScalar ry, Direction dir = kCW Direction)

Appends Round Rect to Path, creating a new closed Contour. Round Rect has bounds equal to rect; each corner is 90 degrees of an ellipse with radii (rx, ry). If dir is kCW Direction, Round Rect starts at top-left of the lower-left corner and winds clockwise. If dir is kCCW Direction, Round Rect starts at the bottom-left of the upper-left corner and winds counterclockwise.

If either rx or ry is too large, rx and ry are scaled uniformly until the corners fit. If rx or ry is less than or equal to zero, addRoundRect appends Rect rect to Path.

After appending, Path may be empty, or may contain: Rect, Oval, or RoundRect.

Parameters

rect	bounds of Round Rect
rx	x-axis radius of rounded corners on the Round Rect
ry	y-axis radius of rounded corners on the Round Rect
dir	Direction to wind Round Rect

Return Value

reference to Path

Example

If either radius is zero, path contains Rect and is drawn red. If sides are only radii, path contains Oval and is drawn blue. All remaining path draws are convex, and are drawn in gray; no paths constructed from addRoundRect are concave, so none are drawn in green.

See Also

addRRect^[2] SkCanvas::drawRoundRect

---

SkPath& addRoundRect(const SkRect& rect, const SkScalar radii[], Direction dir = kCW Direction)

Appends Round Rect to Path, creating a new closed Contour. Round Rect has bounds equal to rect; each corner is 90 degrees of an ellipse with radii from the array.

radii index	location
0	x-axis radius of top-left corner
1	y-axis radius of top-left corner
2	x-axis radius of top-right corner
3	y-axis radius of top-right corner
4	x-axis radius of bottom-right corner
5	y-axis radius of bottom-right corner
6	x-axis radius of bottom-left corner
7	y-axis radius of bottom-left corner

If dir is kCW Direction, Round Rect starts at top-left of the lower-left corner and winds clockwise. If dir is kCCW Direction, Round Rect starts at the bottom-left of the upper-left corner and winds counterclockwise.

If both radii on any side of rect exceed its length, all radii are scaled uniformly until the corners fit. If either radius of a corner is less than or equal to zero, both are treated as zero.

After appending, Path may be empty, or may contain: Rect, Oval, or RoundRect.

Parameters

rect	bounds of Round Rect
radii	array of 8 SkScalar values, a radius pair for each corner
dir	Direction to wind Round Rect

Return Value

reference to Path

Example

See Also

addRRect^[2] SkCanvas::drawRoundRect

---

SkPath& addRRect(const SkRRect& rrect, Direction dir = kCW Direction)

Adds rrect to Path, creating a new closed Contour. If dir is kCW Direction, rrect starts at top-left of the lower-left corner and winds clockwise. If dir is kCCW Direction, rrect starts at the bottom-left of the upper-left corner and winds counterclockwise.

After appending, Path may be empty, or may contain: Rect, Oval, or Round Rect.

Parameters

rrect	bounds and radii of rounded rectangle
dir	Direction to wind Round Rect

Return Value

reference to Path

Example

See Also

addRoundRect^[2] SkCanvas::drawRRect

---

SkPath& addRRect(const SkRRect& rrect, Direction dir, unsigned start)

Adds rrect to Path, creating a new closed Contour. If dir is kCW Direction, rrect winds clockwise; if dir is kCCW Direction, rrect winds counterclockwise. start determines the first point of rrect to add.

start	location
0	right of top-left corner
1	left of top-right corner
2	bottom of top-right corner
3	top of bottom-right corner
4	left of bottom-right corner
5	right of bottom-left corner
6	top of bottom-left corner
7	bottom of top-left corner

After appending, Path may be empty, or may contain: Rect, Oval, or Round Rect.

Parameters

rrect	bounds and radii of rounded rectangle
dir	Direction to wind Round Rect
start	index of initial point of Round Rect

Return Value

reference to Path

Example

See Also

addRoundRect^[2] SkCanvas::drawRRect

---

SkPath& addPoly(const SkPoint pts[], int count, bool close)

Adds Contour created from Line array, adding (count - 1) Line segments. Contour added starts at pts[0], then adds a line for every additional Point in pts array. If close is true, appends kClose Verb to Path, connecting pts[count - 1] and pts[0].

If count is zero, append kMove Verb to path. Has no effect if count is less than one.

Parameters

pts	array of Line sharing end and start Point
count	length of Point array
close	true to add Line connecting Contour end and start

Return Value

reference to Path

Example

See Also

SkCanvas::drawPoints

---

SkPath& addPoly(const std::initializer_list<SkPoint>& list, bool close)

Adds Contour created from list. Contour added starts at list[0], then adds a line for every additional Point in list. If close is true, appends kClose Verb to Path, connecting last and first Point in list.

If list is empty, append kMove Verb to path.

Parameters

list	array of Points
close	true to add Line connecting Contour end and start

Return Value

reference to Path

Example

See Also

SkCanvas::drawPoints

---

    enum AddPathMode {
        kAppend_AddPathMode,
        kExtend_AddPathMode,
    };

AddPathMode chooses how addPath appends. Adding one Path to another can extend the last Contour or start a new Contour.

Constants

Const	Value	Description
SkPath::kAppend_AddPathMode	#Line # appended to destination unaltered ##	Path Verbs, Points, and Conic Weights are appended to destination unaltered. Since Path Verb Array begins with kMove Verb if src is not empty, this starts a new Contour.
SkPath::kExtend_AddPathMode	#Line # add line if prior Contour is not closed ##	If destination is closed or empty, start a new Contour. If destination is not empty, add Line from Last Point to added Path first Point. Skip added Path initial kMove Verb, then append remining Verbs, Points, and Conic Weights.

Example

test is built from path, open on the top row, and closed on the bottom row. The left column uses kAppend AddPathMode; the right uses kExtend AddPathMode. The top right composition is made up of one contour; the other three have two.

See Also

addPath^[2][3] reverseAddPath

---

SkPath& addPath(const SkPath& src, SkScalar dx, SkScalar dy, AddPathMode mode = kAppend AddPathMode)

Appends src to Path, offset by (dx, dy).

If mode is kAppend AddPathMode, src Verb Array, Point Array, and Conic Weights are added unaltered. If mode is kExtend AddPathMode, add Line before appending Verbs, Points, and Conic Weights.

Parameters

src	Path Verbs, Points, and Conic Weights to add
dx	offset added to src Point Array x-axis coordinates
dy	offset added to src Point Array y-axis coordinates
mode	kAppend AddPathMode or kExtend AddPathMode

Return Value

reference to Path

Example

See Also

AddPathMode offset^[2] reverseAddPath

---

SkPath& addPath(const SkPath& src, AddPathMode mode = kAppend AddPathMode)

Appends src to Path.

If mode is kAppend AddPathMode, src Verb Array, Point Array, and Conic Weights are added unaltered. If mode is kExtend AddPathMode, add Line before appending Verbs, Points, and Conic Weights.

Parameters

src	Path Verbs, Points, and Conic Weights to add
mode	kAppend AddPathMode or kExtend AddPathMode

Return Value

reference to Path

Example

See Also

AddPathMode reverseAddPath

---

SkPath& addPath(const SkPath& src, const SkMatrix& matrix, AddPathMode mode = kAppend AddPathMode)

Appends src to Path, transformed by matrix. Transformed curves may have different Verbs, Points, and Conic Weights.

If mode is kAppend AddPathMode, src Verb Array, Point Array, and Conic Weights are added unaltered. If mode is kExtend AddPathMode, add Line before appending Verbs, Points, and Conic Weights.

Parameters

src	Path Verbs, Points, and Conic Weights to add
matrix	transform applied to src
mode	kAppend AddPathMode or kExtend AddPathMode

Return Value

reference to Path

Example

See Also

AddPathMode transform^[2] offset^[2] reverseAddPath

---

SkPath& reverseAddPath(const SkPath& src)

Appends src to Path, from back to front. Reversed src always appends a new Contour to Path.

Parameters

src	Path Verbs, Points, and Conic Weights to add

Return Value

reference to Path

Example

See Also

AddPathMode transform^[2] offset^[2] addPath^[2][3]

---

void offset(SkScalar dx, SkScalar dy, SkPath* dst) const

Offsets Point Array by (dx, dy). Offset Path replaces dst. If dst is nullptr, Path is replaced by offset data.

Parameters

dx	offset added to Point Array x-axis coordinates
dy	offset added to Point Array y-axis coordinates
dst	overwritten, translated copy of Path; may be nullptr

Example

See Also

addPath^[2][3] transform^[2]

---

void offset(SkScalar dx, SkScalar dy)

Offsets Point Array by (dx, dy). Path is replaced by offset data.

Parameters

dx	offset added to Point Array x-axis coordinates
dy	offset added to Point Array y-axis coordinates

Example

See Also

addPath^[2][3] transform^[2] SkCanvas::translate()

---

void transform(const SkMatrix& matrix, SkPath* dst) const

Transforms Verb Array, Point Array, and weight by matrix. transform may change Verbs and increase their number. Transformed Path replaces dst; if dst is nullptr, original data is replaced.

Parameters

matrix	Matrix to apply to Path
dst	overwritten, transformed copy of Path; may be nullptr

Example

See Also

addPath^[2][3] offset^[2] SkCanvas::concat() SkMatrix

---

void transform(const SkMatrix& matrix)

Transforms Verb Array, Point Array, and weight by matrix. transform may change Verbs and increase their number. Path is replaced by transformed data.

Parameters

matrix

Matrix to apply to Path

Example

See Also

addPath^[2][3] offset^[2] SkCanvas::concat() SkMatrix

Path is defined cumulatively, often by adding a segment to the end of last Contour. Last Point of Contour is shared as first Point of added Line or Curve. Last Point can be read and written directly with getLastPt and setLastPt.

---

bool getLastPt(SkPoint* lastPt) const

Returns Last Point on Path in lastPt. Returns false if Point Array is empty, storing (0, 0) if lastPt is not nullptr.

Parameters

lastPt

storage for final Point in Point Array; may be nullptr

Return Value

true if Point Array contains one or more Points

Example

Example Output

last point: 35.2786, 52.9772

See Also

setLastPt^[2]

---

void setLastPt(SkScalar x, SkScalar y)

Sets Last Point to (x, y). If Point Array is empty, append kMove Verb to Verb Array and append (x, y) to Point Array.

Parameters

x	set x-axis value of Last Point
y	set y-axis value of Last Point

Example

See Also

getLastPt

---

void setLastPt(const SkPoint& p)

Sets the last point on the path. If Point Array is empty, append kMove Verb to Verb Array and append p to Point Array.

Parameters

p	set value of Last Point

Example

See Also

getLastPt

---

    enum SegmentMask {
        kLine_SegmentMask = 1 << 0,
        kQuad_SegmentMask = 1 << 1,
        kConic_SegmentMask = 1 << 2,
        kCubic_SegmentMask = 1 << 3,
    };

SegmentMask constants correspond to each drawing Verb type in Path; for instance, if Path only contains Lines, only the kLine SegmentMask bit is set.

Constants

Const	Value	Description
SkPath::kLine_SegmentMask	1	Set if Verb Array contains kLine Verb.
SkPath::kQuad_SegmentMask	2	Set if Verb Array contains kQuad Verb. Note that conicTo may add a Quad.
SkPath::kConic_SegmentMask	4	Set if Verb Array contains kConic Verb.
SkPath::kCubic_SegmentMask	8	Set if Verb Array contains kCubic Verb.

Example

When conicTo has a weight of one, Quad is added to Path.

Example Output

Path kConic_SegmentMask is clear
Path kQuad_SegmentMask is set

See Also

getSegmentMasks Verb

---

uint32_t getSegmentMasks() const

Returns a mask, where each set bit corresponds to a SegmentMask constant if Path contains one or more Verbs of that type. Returns zero if Path contains no Lines, or Curves: Quads, Conics, or Cubics.

getSegmentMasks() returns a cached result; it is very fast.

Return Value

SegmentMask bits or zero

Example

Example Output

mask quad set

See Also

getSegmentMasks Verb

---

bool contains(SkScalar x, SkScalar y) const

Returns true if the point (x, y) is contained by Path, taking into account FillType.

FillType	contains() returns true if Point is enclosed by
kWinding FillType	a non-zero sum of Contour Directions.
kEvenOdd FillType	an odd number of Contours.
kInverseWinding FillType	a zero sum of Contour Directions.
kInverseEvenOdd FillType	and even number of Contours.

Parameters

x	x-axis value of containment test
y	y-axis value of containment test

Return Value

true if Point is in Path

Example

See Also

conservativelyContainsRect Fill Type Op

---

void dump(SkWStream* stream, bool forceClose, bool dumpAsHex) const

Writes text representation of Path to stream. If stream is nullptr, writes to standard output. Set forceClose to true to get edges used to fill Path. Set dumpAsHex true to generate exact binary representations of floating point numbers used in Point Array and Conic Weights.

Parameters

stream	writable WStream receiving Path text representation; may be nullptr
forceClose	true if missing kClose Verb is output
dumpAsHex	true if SkScalar values are written as hexadecimal

Example

Example Output

path.setFillType(SkPath::kWinding_FillType);
path.moveTo(0, 0);
path.quadTo(20, 30, 40, 50);
path.setFillType(SkPath::kWinding_FillType);
path.moveTo(SkBits2Float(0x00000000), SkBits2Float(0x00000000));  // 0, 0
path.quadTo(SkBits2Float(0x41a00000), SkBits2Float(0x41f00000), SkBits2Float(0x42200000), SkBits2Float(0x42480000));  // 20, 30, 40, 50
path.setFillType(SkPath::kWinding_FillType);
path.moveTo(0, 0);
path.quadTo(20, 30, 40, 50);
path.lineTo(0, 0);
path.close();
path.setFillType(SkPath::kWinding_FillType);
path.moveTo(SkBits2Float(0x00000000), SkBits2Float(0x00000000));  // 0, 0
path.quadTo(SkBits2Float(0x41a00000), SkBits2Float(0x41f00000), SkBits2Float(0x42200000), SkBits2Float(0x42480000));  // 20, 30, 40, 50
path.lineTo(SkBits2Float(0x00000000), SkBits2Float(0x00000000));  // 0, 0
path.close();

See Also

dumpHex SkRect::dump^[2]() SkRRect::dump^[2]() SkPathMeasure::dump()

---

void dump() const

Writes text representation of Path to standard output. The representation may be directly compiled as C++ code. Floating point values are written with limited precision; it may not be possible to reconstruct original Path from output.

Example

Example Output

path.setFillType(SkPath::kWinding_FillType);
path.moveTo(0, 0);
path.lineTo(0.857143f, 0.666667f);
path is not equal to copy

See Also

dumpHex SkRect::dump^[2]() SkRRect::dump^[2]() SkPathMeasure::dump() writeToMemory

---

void dumpHex() const

Writes text representation of Path to standard output. The representation may be directly compiled as C++ code. Floating point values are written in hexadecimal to preserve their exact bit pattern. The output reconstructs the original Path.

Use instead of dump() when submitting bug reports against Skia .

Example

Example Output

path.setFillType(SkPath::kWinding_FillType);
path.moveTo(SkBits2Float(0x00000000), SkBits2Float(0x00000000));  // 0, 0
path.lineTo(SkBits2Float(0x3f5b6db7), SkBits2Float(0x3f2aaaab));  // 0.857143f, 0.666667f
path is equal to copy

See Also

dump^[2] SkRect::dumpHex SkRRect::dumpHex writeToMemory

---

size_t writeToMemory(void* buffer) const

Writes Path to buffer, returning the number of bytes written. Pass nullptr to obtain the storage size.

Writes Fill Type, Verb Array, Point Array, Conic Weight, and additionally writes computed information like Convexity and bounds.

Use only be used in concert with readFromMemory; the format used for Path in memory is not guaranteed.

Parameters

buffer

storage for Path; may be nullptr

Return Value

size of storage required for Path; always a multiple of 4

Example

Example Output

path is equal to copy

See Also

serialize readFromMemory dump^[2] dumpHex

---

sk sp<SkData> serialize() const

Writes Path to buffer, returning the buffer written to, wrapped in Data.

serialize() writes Fill Type, Verb Array, Point Array, Conic Weight, and additionally writes computed information like Convexity and bounds.

serialize() should only be used in concert with readFromMemory. The format used for Path in memory is not guaranteed.

Return Value

Path data wrapped in Data buffer

Example

Example Output

path is equal to copy

See Also

writeToMemory readFromMemory dump^[2] dumpHex

---

size_t readFromMemory(const void* buffer, size_t length)

Initializes Path from buffer of size length. Returns zero if the buffer is data is inconsistent, or the length is too small.

Reads Fill Type, Verb Array, Point Array, Conic Weight, and additionally reads computed information like Convexity and bounds.

Used only in concert with writeToMemory; the format used for Path in memory is not guaranteed.

Parameters

buffer	storage for Path
length	buffer size in bytes; must be multiple of 4

Return Value

number of bytes read, or zero on failure

Example

Example Output

length = 32; returned by readFromMemory = 0
length = 40; returned by readFromMemory = 36

See Also

writeToMemory

Generation ID provides a quick way to check if Verb Array, Point Array, or Conic Weight has changed. Generation ID is not a hash; identical Paths will not necessarily have matching Generation IDs.

Empty Paths have a Generation ID of one.

---

uint32_t getGenerationID() const

Returns a non-zero, globally unique value. A different value is returned if Verb Array, Point Array, or Conic Weight changes.

Setting Fill Type does not change Generation ID.

Each time the path is modified, a different Generation ID will be returned.

Fill Type does affect Generation ID on Android framework.

Return Value

non-zero, globally unique value

Example

Example Output

empty genID = 1
1st lineTo genID = 2
empty genID = 1
2nd lineTo genID = 3

See Also

operator==(const SkPath& a, const SkPath& b)

---

bool isValid() const

Returns if Path data is consistent. Corrupt Path data is detected if internal values are out of range or internal storage does not match array dimensions.

Return Value

true if Path data is consistent

---

bool pathRefIsValid() const

To be deprecated soon.

---

    class Iter {
    public:
        Iter();
        Iter(const SkPath& path, bool forceClose);
        void setPath(const SkPath& path, bool forceClose);
        Verb next(SkPoint pts[4], bool doConsumeDegenerates = true, bool exact = false);
        SkScalar conicWeight() const;
        bool isCloseLine() const;
        bool isClosedContour() const;
    };

Iterates through Verb Array, and associated Point Array and Conic Weight. Provides options to treat open Contours as closed, and to ignore degenerate data.

Example

Ignoring the actual Verbs and replacing them with Quads rounds the path of the glyph.

See Also

RawIter

---

Iter()

Initializes Iter with an empty Path. next() on Iter returns kDone Verb. Call setPath to initialize Iter at a later time.

Return Value

Iter of empty Path

Example

Example Output

iter is done
iter is done

See Also

setPath

---

Iter(const SkPath& path, bool forceClose)

Sets Iter to return elements of Verb Array, Point Array, and Conic Weight in path. If forceClose is true, Iter will add kLine Verb and kClose Verb after each open Contour. path is not altered.

Parameters

path	Path to iterate
forceClose	true if open Contours generate kClose Verb

Return Value

Iter of path

Example

Example Output

open:
kMove_Verb {0, 0},
kQuad_Verb {0, 0}, {10, 20}, {30, 40},
kDone_Verb
closed:
kMove_Verb {0, 0},
kQuad_Verb {0, 0}, {10, 20}, {30, 40},
kLine_Verb {30, 40}, {0, 0},
kClose_Verb {0, 0},
kDone_Verb

See Also

setPath

---

void setPath(const SkPath& path, bool forceClose)

Sets Iter to return elements of Verb Array, Point Array, and Conic Weight in path. If forceClose is true, Iter will add kLine Verb and kClose Verb after each open Contour. path is not altered.

Parameters

path	Path to iterate
forceClose	true if open Contours generate kClose Verb

Example

Example Output

quad open:
kMove_Verb {0, 0},
kQuad_Verb {0, 0}, {10, 20}, {30, 40},
kDone_Verb
conic closed:
kMove_Verb {0, 0},
kConic_Verb {0, 0}, {1, 2}, {3, 4}, weight = 0.5
kLine_Verb {3, 4}, {0, 0},
kClose_Verb {0, 0},
kDone_Verb

See Also

Iter(const SkPath& path, bool forceClose)

---

Verb next(SkPoint pts[4], bool doConsumeDegenerates = true, bool exact = false)

Returns next Verb in Verb Array, and advances Iter. When Verb Array is exhausted, returns kDone Verb.

Zero to four Points are stored in pts, depending on the returned Verb.

If doConsumeDegenerates is true, skip consecutive kMove Verb entries, returning only the last in the series; and skip very small Lines, Quads, and Conics; and skip kClose Verb following kMove Verb. if doConsumeDegenerates is true and exact is true, only skip Lines, Quads, and Conics with zero lengths.

Parameters

pts	storage for Point data describing returned Verb
doConsumeDegenerates	if true, skip degenerate Verbs
exact	skip zero length curves

Return Value

next Verb from Verb Array

Example

skip degenerate skips the first in a kMove Verb pair, the kMove Verb followed by the kClose Verb, the zero length Line and the very small Line.

skip degenerate if exact skips the same as skip degenerate, but shows the very small Line.

skip none shows all of the Verbs and Points in Path.

Example Output

skip degenerate:
kMove_Verb {20, 20},
kQuad_Verb {20, 20}, {10, 20}, {30, 40},
kDone_Verb
skip degenerate if exact:
kMove_Verb {20, 20},
kQuad_Verb {20, 20}, {10, 20}, {30, 40},
kMove_Verb {30, 30},
kLine_Verb {30, 30}, {30.00001, 30},
kDone_Verb
skip none:
kMove_Verb {10, 10},
kMove_Verb {20, 20},
kQuad_Verb {20, 20}, {10, 20}, {30, 40},
kMove_Verb {1, 1},
kClose_Verb {1, 1},
kMove_Verb {30, 30},
kLine_Verb {30, 30}, {30, 30},
kMove_Verb {30, 30},
kLine_Verb {30, 30}, {30.00001, 30},
kDone_Verb

See Also

Verb IsLineDegenerate IsCubicDegenerate IsQuadDegenerate

---

SkScalar conicWeight() const

Returns Conic Weight if next() returned kConic Verb.

If next() has not been called, or next() did not return kConic Verb, result is undefined.

Return Value

Conic Weight for Conic Points returned by next()

Example

Example Output

first verb is move
next verb is conic
conic points: {0,0}, {1,2}, {3,4}
conic weight: 0.5

See Also

Conic Weight

---

bool isCloseLine() const

Returns true if last kLine Verb returned by next() was generated by kClose Verb. When true, the end point returned by next() is also the start point of Contour.

If next() has not been called, or next() did not return kLine Verb, result is undefined.

Return Value

true if last kLine Verb was generated by kClose Verb

Example

Example Output

1st verb is move
moveTo point: {6,7}
2nd verb is conic
3rd verb is line
line points: {3,4}, {6,7}
line generated by close
4th verb is close

See Also

close()

---

bool isClosedContour() const

Returns true if subsequent calls to next() return kClose Verb before returning kMove Verb. if true, Contour Iter is processing may end with kClose Verb, or Iter may have been initialized with force close set to true.

Return Value

true if Contour is closed

Example

Example Output

without close(), forceClose is false: isClosedContour returns false
with close(),    forceClose is false: isClosedContour returns true
without close(), forceClose is true : isClosedContour returns true
with close(),    forceClose is true : isClosedContour returns true

See Also

Iter(const SkPath& path, bool forceClose)

---

    class RawIter {
    public:
        RawIter();
        RawIter(const SkPath& path);
        void setPath(const SkPath& path);
        Verb next(SkPoint pts[4]);
        Verb peek() const;
        SkScalar conicWeight() const;
    };

Iterates through Verb Array, and associated Point Array and Conic Weight. Verb Array, Point Array, and Conic Weight are returned unaltered.

---

RawIter()

Initializes RawIter with an empty Path. next() on RawIter returns kDone Verb. Call setPath to initialize SkPath::Iter at a later time.

Return Value

RawIter of empty Path

---

RawIter(const SkPath& path)

Sets RawIter to return elements of Verb Array, Point Array, and Conic Weight in path.

Parameters

path	Path to iterate

Return Value

RawIter of path

---

void setPath(const SkPath& path)

Sets SkPath::Iter to return elements of Verb Array, Point Array, and Conic Weight in path.

Parameters

path	Path to iterate

---

Verb next(SkPoint pts[4])

Returns next Verb in Verb Array, and advances RawIter. When Verb Array is exhausted, returns kDone Verb. Zero to four Points are stored in pts, depending on the returned Verb.

Parameters

pts	storage for Point data describing returned Verb

Return Value

next Verb from Verb Array

Example

Example Output

kMove_Verb {50, 60},
kQuad_Verb {50, 60}, {10, 20}, {30, 40},
kClose_Verb {50, 60},
kMove_Verb {50, 60},
kLine_Verb {50, 60}, {30, 30},
kConic_Verb {30, 30}, {1, 2}, {3, 4}, weight = 0.5
kCubic_Verb {3, 4}, {-1, -2}, {-3, -4}, {-5, -6},
kDone_Verb

See Also

peek()

---

Verb peek() const

Returns next Verb, but does not advance RawIter.

Return Value

next Verb from Verb Array

Example

Example Output

#Volatile
peek Move == verb Move
peek Quad == verb Quad
peek Conic == verb Conic
peek Cubic == verb Cubic
peek Done == verb Done
peek Done == verb Done

StdOut is not really volatile, it just produces the wrong result. A simple fix changes the output of hairlines and needs to be investigated to see if the change is correct or not. see change 21340 (abandoned for now)

See Also

next

---

SkScalar conicWeight() const

Returns Conic Weight if next() returned kConic Verb.

If next() has not been called, or next() did not return kConic Verb, result is undefined.

Return Value

Conic Weight for Conic Points returned by next()

Example

Example Output

first verb is move
next verb is conic
conic points: {0,0}, {1,2}, {3,4}
conic weight: 0.5

See Also

Conic Weight