SkPath.h

/*
 * Copyright 2006 The Android Open Source Project
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef SkPath_DEFINED
#define SkPath_DEFINED

#include "SkMatrix.h"
#include "../private/SkPathRef.h"

class SkAutoPathBoundsUpdate;
class SkRRect;
class SkWStream;

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

    SkPath();
    SkPath(const SkPath& path);
    ~SkPath();

    SkPath& operator=(const SkPath& path);
    // mac chromium dbg requires SK_API to make operator== visible
    friend SK_API bool operator==(const SkPath& a, const SkPath& b);
    friend bool operator!=(const SkPath& a, const SkPath& b) {
        return !(a == b);
    }

    bool isInterpolatable(const SkPath& compare) const;

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

#ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK

    bool unique() const { return fPathRef->unique(); }
#endif

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

    FillType getFillType() const { return (FillType)fFillType; }

    void setFillType(FillType ft) {
        fFillType = SkToU8(ft);
    }

    bool isInverseFillType() const { return IsInverseFillType((FillType)fFillType); }

    void toggleInverseFillType() {
        fFillType ^= 2;
    }

    enum Convexity {
        kUnknown_Convexity,
        kConvex_Convexity,
        kConcave_Convexity
    };

    Convexity getConvexity() const {
        if (kUnknown_Convexity != fConvexity) {
            return static_cast<Convexity>(fConvexity);
        } else {
            return this->internalGetConvexity();
        }
    }

    Convexity getConvexityOrUnknown() const { return (Convexity)fConvexity; }

    void setConvexity(Convexity convexity);

    bool isConvex() const {
        return kConvex_Convexity == this->getConvexity();
    }

    SK_ATTR_DEPRECATED("use setConvexity")
    void setIsConvex(bool isConvex) {
        this->setConvexity(isConvex ? kConvex_Convexity : kConcave_Convexity);
    }

    bool isOval(SkRect* rect, Direction* dir = nullptr,
                unsigned* start = nullptr) const {
        bool isCCW = false;
        bool result = fPathRef->isOval(rect, &isCCW, start);
        if (dir && result) {
            *dir = isCCW ? kCCW_Direction : kCW_Direction;
        }
        return result;
    }

    bool isRRect(SkRRect* rrect, Direction* dir = nullptr,
                 unsigned* start = nullptr) const {
        bool isCCW = false;
        bool result = fPathRef->isRRect(rrect, &isCCW, start);
        if (dir && result) {
            *dir = isCCW ? kCCW_Direction : kCW_Direction;
        }
        return result;
    }

    void reset();

    void rewind();

    bool isEmpty() const {
        SkDEBUGCODE(this->validate();)
        return 0 == fPathRef->countVerbs();
    }

    bool isLastContourClosed() const;

    bool isFinite() const {
        SkDEBUGCODE(this->validate();)
        return fPathRef->isFinite();
    }

    bool isVolatile() const {
        return SkToBool(fIsVolatile);
    }

    void setIsVolatile(bool isVolatile) {
        fIsVolatile = isVolatile;
    }

    static bool IsLineDegenerate(const SkPoint& p1, const SkPoint& p2, bool exact) {
        return exact ? p1 == p2 : p1.equalsWithinTolerance(p2);
    }

    static bool IsQuadDegenerate(const SkPoint& p1, const SkPoint& p2,
                                 const SkPoint& p3, bool exact) {
        return exact ? p1 == p2 && p2 == p3 : p1.equalsWithinTolerance(p2) &&
               p2.equalsWithinTolerance(p3);
    }

    static bool IsCubicDegenerate(const SkPoint& p1, const SkPoint& p2,
                                  const SkPoint& p3, const SkPoint& p4, bool exact) {
        return exact ? p1 == p2 && p2 == p3 && p3 == p4 : p1.equalsWithinTolerance(p2) &&
               p2.equalsWithinTolerance(p3) &&
               p3.equalsWithinTolerance(p4);
    }

    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 {
        return fPathRef->getBounds();
    }

    void updateBoundsCache() const {
        // for now, just calling getBounds() is sufficient
        this->getBounds();
    }

    SkRect computeTightBounds() const;

    bool conservativelyContainsRect(const SkRect& rect) const;

    //  Construction methods

    void incReserve(unsigned extraPtCount);

    void moveTo(SkScalar x, SkScalar y);

    void moveTo(const SkPoint& p) {
        this->moveTo(p.fX, p.fY);
    }

    void rMoveTo(SkScalar dx, SkScalar dy);

    void lineTo(SkScalar x, SkScalar y);

    void lineTo(const SkPoint& p) {
        this->lineTo(p.fX, p.fY);
    }

    void rLineTo(SkScalar dx, SkScalar dy);

    void quadTo(SkScalar x1, SkScalar y1, SkScalar x2, SkScalar y2);

    void quadTo(const SkPoint& p1, const SkPoint& p2) {
        this->quadTo(p1.fX, p1.fY, p2.fX, p2.fY);
    }

    void rQuadTo(SkScalar dx1, SkScalar dy1, SkScalar dx2, SkScalar dy2);

    void conicTo(SkScalar x1, SkScalar y1, SkScalar x2, SkScalar y2,
                 SkScalar w);
    void conicTo(const SkPoint& p1, const SkPoint& p2, SkScalar w) {
        this->conicTo(p1.fX, p1.fY, p2.fX, p2.fY, w);
    }
    void rConicTo(SkScalar dx1, SkScalar dy1, SkScalar dx2, SkScalar dy2,
                  SkScalar w);

    void cubicTo(SkScalar x1, SkScalar y1, SkScalar x2, SkScalar y2,
                 SkScalar x3, SkScalar y3);

    void cubicTo(const SkPoint& p1, const SkPoint& p2, const SkPoint& p3) {
        this->cubicTo(p1.fX, p1.fY, p2.fX, p2.fY, p3.fX, p3.fY);
    }

    void rCubicTo(SkScalar x1, SkScalar y1, SkScalar x2, SkScalar y2,
                  SkScalar x3, SkScalar y3);

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

    void arcTo(SkScalar x1, SkScalar y1, SkScalar x2, SkScalar y2, SkScalar radius);

    void arcTo(const SkPoint p1, const SkPoint p2, SkScalar radius) {
        this->arcTo(p1.fX, p1.fY, p2.fX, p2.fY, radius);
    }

    enum ArcSize {
        kSmall_ArcSize,
        kLarge_ArcSize,
    };

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

    void arcTo(const SkPoint r, SkScalar xAxisRotate, ArcSize largeArc, Direction sweep,
               const SkPoint xy) {
        this->arcTo(r.fX, r.fY, xAxisRotate, largeArc, sweep, xy.fX, xy.fY);
    }

    void rArcTo(SkScalar rx, SkScalar ry, SkScalar xAxisRotate, ArcSize largeArc,
                Direction sweep, SkScalar dx, SkScalar dy);

    void close();

    static bool IsInverseFillType(FillType fill) {
        static_assert(0 == kWinding_FillType, "fill_type_mismatch");
        static_assert(1 == kEvenOdd_FillType, "fill_type_mismatch");
        static_assert(2 == kInverseWinding_FillType, "fill_type_mismatch");
        static_assert(3 == kInverseEvenOdd_FillType, "fill_type_mismatch");
        return (fill & 2) != 0;
    }

    static FillType ConvertToNonInverseFillType(FillType fill) {
        static_assert(0 == kWinding_FillType, "fill_type_mismatch");
        static_assert(1 == kEvenOdd_FillType, "fill_type_mismatch");
        static_assert(2 == kInverseWinding_FillType, "fill_type_mismatch");
        static_assert(3 == kInverseEvenOdd_FillType, "fill_type_mismatch");
        return (FillType)(fill & 1);
    }

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

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

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

    void addRect(const SkRect& rect, Direction dir = kCW_Direction);

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

    void addRect(SkScalar left, SkScalar top, SkScalar right, SkScalar bottom,
                 Direction dir = kCW_Direction);

    void addOval(const SkRect& oval, Direction dir = kCW_Direction);

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

    void addCircle(SkScalar x, SkScalar y, SkScalar radius,
                   Direction dir = kCW_Direction);

    void addArc(const SkRect& oval, SkScalar startAngle, SkScalar sweepAngle);

    void addRoundRect(const SkRect& rect, SkScalar rx, SkScalar ry,
                      Direction dir = kCW_Direction);

    void addRoundRect(const SkRect& rect, const SkScalar radii[],
                      Direction dir = kCW_Direction);

    void addRRect(const SkRRect& rrect, Direction dir = kCW_Direction);

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

    void addPoly(const SkPoint pts[], int count, bool close);

    enum AddPathMode {
        kAppend_AddPathMode,
        kExtend_AddPathMode
    };

    void addPath(const SkPath& src, SkScalar dx, SkScalar dy,
                 AddPathMode mode = kAppend_AddPathMode);

    void addPath(const SkPath& src, AddPathMode mode = kAppend_AddPathMode) {
        SkMatrix m;
        m.reset();
        this->addPath(src, m, mode);
    }

    void addPath(const SkPath& src, const SkMatrix& matrix, AddPathMode mode = kAppend_AddPathMode);

    void reverseAddPath(const SkPath& src);

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

    void offset(SkScalar dx, SkScalar dy) {
        this->offset(dx, dy, this);
    }

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

    void transform(const SkMatrix& matrix) {
        this->transform(matrix, this);
    }

    bool getLastPt(SkPoint* lastPt) const;

    void setLastPt(SkScalar x, SkScalar y);

    void setLastPt(const SkPoint& p) {
        this->setLastPt(p.fX, p.fY);
    }

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

    uint32_t getSegmentMasks() const { return fPathRef->getSegmentMasks(); }

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

    class SK_API Iter {
    public:
        Iter();
        Iter(const SkPath&, bool forceClose);

        void setPath(const SkPath&, bool forceClose);

        Verb next(SkPoint pts[4], bool doConsumeDegerates = true, bool exact = false) {
            if (doConsumeDegerates) {
                this->consumeDegenerateSegments(exact);
            }
            return this->doNext(pts);
        }

        SkScalar conicWeight() const { return *fConicWeights; }

        bool isCloseLine() const { return SkToBool(fCloseLine); }

        bool isClosedContour() const;

    private:
        const SkPoint*  fPts;
        const uint8_t*  fVerbs;
        const uint8_t*  fVerbStop;
        const SkScalar* fConicWeights;
        SkPoint         fMoveTo;
        SkPoint         fLastPt;
        SkBool8         fForceClose;
        SkBool8         fNeedClose;
        SkBool8         fCloseLine;
        SkBool8         fSegmentState;

        inline const SkPoint& cons_moveTo();
        Verb autoClose(SkPoint pts[2]);
        void consumeDegenerateSegments(bool exact);
        Verb doNext(SkPoint pts[4]);
    };

    class SK_API RawIter {
    public:
        RawIter() {}
        RawIter(const SkPath& path) {
            setPath(path);
        }

        void setPath(const SkPath& path) {
            fRawIter.setPathRef(*path.fPathRef.get());
        }

        Verb next(SkPoint pts[4]) {
            return (Verb) fRawIter.next(pts);
        }

        Verb peek() const {
            return (Verb) fRawIter.peek();
        }

        SkScalar conicWeight() const {
            return fRawIter.conicWeight();
        }

    private:
        SkPathRef::Iter fRawIter;
        friend class SkPath;
    };

    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;
    size_t readFromMemory(const void* buffer, size_t length);

    uint32_t getGenerationID() const;

#ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
    static const int kPathRefGenIDBitCnt = 30; // leave room for the fill type (skbug.com/1762)
#else
    static const int kPathRefGenIDBitCnt = 32;
#endif

    SkDEBUGCODE(void validate() const;)
    SkDEBUGCODE(void experimentalValidateRef() const { fPathRef->validate(); } )

private:
    enum SerializationOffsets {
        // 1 free bit at 29
        kUnused1_SerializationShift = 28,    // 1 free bit
        kDirection_SerializationShift = 26, // requires 2 bits
        kIsVolatile_SerializationShift = 25, // requires 1 bit
        // 1 free bit at 24
        kConvexity_SerializationShift = 16, // requires 8 bits
        kFillType_SerializationShift = 8,   // requires 8 bits
        // low-8-bits are version
    };

    enum SerializationVersions {
        kPathPrivFirstDirection_Version = 1,
        kPathPrivLastMoveToIndex_Version = 2,
        kCurrent_Version = 2
    };

    sk_sp<SkPathRef>                                   fPathRef;
    int                                                fLastMoveToIndex;
    uint8_t                                            fFillType;
    mutable uint8_t                                    fConvexity;
    mutable SkAtomic<uint8_t, sk_memory_order_relaxed> fFirstDirection;// SkPathPriv::FirstDirection
    SkBool8                                            fIsVolatile;

    void resetFields();

    void copyFields(const SkPath& that);

    friend class Iter;
    friend class SkPathPriv;
    friend class SkPathStroker;

    /*  Append, in reverse order, the first contour of path, ignoring path's
        last point. If no moveTo() call has been made for this contour, the
        first point is automatically set to (0,0).
    */
    void reversePathTo(const SkPath&);

    // called before we add points for lineTo, quadTo, cubicTo, checking to see
    // if we need to inject a leading moveTo first
    //
    //  SkPath path; path.lineTo(...);   <--- need a leading moveTo(0, 0)
    // SkPath path; ... path.close(); path.lineTo(...) <-- need a moveTo(previous moveTo)
    //
    inline void injectMoveToIfNeeded();

    inline bool hasOnlyMoveTos() const;

    Convexity internalGetConvexity() const;

    bool isRectContour(bool allowPartial, int* currVerb, const SkPoint** pts,
                       bool* isClosed, Direction* direction) const;

    // called by stroker to see if all points are equal and worthy of a cap
    // equivalent to a short-circuit version of getBounds().isEmpty() 
    bool isZeroLength() const;

    bool hasComputedBounds() const {
        SkDEBUGCODE(this->validate();)
        return fPathRef->hasComputedBounds();
    }


    // 'rect' needs to be sorted
    void setBounds(const SkRect& rect) {
        SkPathRef::Editor ed(&fPathRef);

        ed.setBounds(rect);
    }

    void setPt(int index, SkScalar x, SkScalar y);

    friend class SkAutoPathBoundsUpdate;
    friend class SkAutoDisableOvalCheck;
    friend class SkAutoDisableDirectionCheck;
    friend class SkPathWriter;
    friend class SkOpBuilder;
    friend class SkBench_AddPathTest; // perf test reversePathTo
    friend class PathTest_Private; // unit test reversePathTo
    friend class ForceIsRRect_Private; // unit test isRRect
};

#endif