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      1 /*
      2  * Copyright 2012 Google Inc.
      3  *
      4  * Use of this source code is governed by a BSD-style license that can be
      5  * found in the LICENSE file.
      6  */
      7 #ifndef SkOpAngle_DEFINED
      8 #define SkOpAngle_DEFINED
      9 
     10 #include "SkChunkAlloc.h"
     11 #include "SkLineParameters.h"
     12 
     13 class SkOpSegment;
     14 struct SkOpSpan;
     15 
     16 // sorting angles
     17 // given angles of {dx dy ddx ddy dddx dddy} sort them
     18 class SkOpAngle {
     19 public:
     20     enum { kStackBasedCount = 8 }; // FIXME: determine what this should be
     21     enum IncludeType {
     22         kUnaryWinding,
     23         kUnaryXor,
     24         kBinarySingle,
     25         kBinaryOpp,
     26     };
     27 
     28 
     29     int end() const {
     30         return fEnd;
     31     }
     32 
     33     const SkOpAngle* findFirst() const;
     34 
     35     bool inLoop() const {
     36         return !!fNext;
     37     }
     38 
     39     void insert(SkOpAngle* );
     40     bool isHorizontal() const;
     41     SkOpSpan* lastMarked() const;
     42     bool loopContains(const SkOpAngle& ) const;
     43     int loopCount() const;
     44     void markStops();
     45     bool merge(SkOpAngle* );
     46 
     47     SkOpAngle* next() const {
     48         return fNext;
     49     }
     50 
     51     SkOpAngle* previous() const;
     52 
     53     void set(const SkOpSegment* segment, int start, int end);
     54 
     55     void setLastMarked(SkOpSpan* marked) {
     56         fLastMarked = marked;
     57     }
     58 
     59     SkOpSegment* segment() const {
     60         return const_cast<SkOpSegment*>(fSegment);
     61     }
     62 
     63     int sign() const {
     64         return SkSign32(fStart - fEnd);
     65     }
     66 
     67     bool small() const;
     68 
     69     int start() const {
     70         return fStart;
     71     }
     72 
     73     bool unorderable() const {
     74         return fUnorderable;
     75     }
     76 
     77     // available to testing only
     78 #if DEBUG_SORT
     79     void debugLoop() const;  // called by code during run
     80 #endif
     81 #if DEBUG_ANGLE
     82     void debugSameAs(const SkOpAngle* compare) const;
     83 #endif
     84     void dump() const;
     85     void dumpLoop() const;
     86     void dumpTo(const SkOpSegment* fromSeg, const SkOpAngle* ) const;
     87 
     88 #if DEBUG_ANGLE
     89     int debugID() const { return fID; }
     90 
     91     void setID(int id) {
     92         fID = id;
     93     }
     94 #else
     95     int debugID() const { return 0; }
     96 #endif
     97 
     98 #if DEBUG_VALIDATE
     99     void debugValidateLoop() const;
    100 #endif
    101 
    102 private:
    103     bool after(const SkOpAngle* test) const;
    104     int allOnOneSide(const SkOpAngle& test) const;
    105     bool calcSlop(double x, double y, double rx, double ry, bool* result) const;
    106     bool checkCrossesZero() const;
    107     bool checkParallel(const SkOpAngle& ) const;
    108     bool computeSector();
    109     int convexHullOverlaps(const SkOpAngle& ) const;
    110     double distEndRatio(double dist) const;
    111     int findSector(SkPath::Verb verb, double x, double y) const;
    112     bool endsIntersect(const SkOpAngle& ) const;
    113     double midT() const;
    114     bool oppositePlanes(const SkOpAngle& rh) const;
    115     bool orderable(const SkOpAngle& rh) const;  // false == this < rh ; true == this > rh
    116     bool overlap(const SkOpAngle& test) const;
    117     void setCurveHullSweep();
    118     void setSector();
    119     void setSpans();
    120     bool tangentsDiverge(const SkOpAngle& rh, double s0xt0) const;
    121 
    122     SkDCubic fCurvePart; // the curve from start to end
    123     double fSide;
    124     SkLineParameters fTangentHalf;  // used only to sort a pair of lines or line-like sections
    125     const SkOpSegment* fSegment;
    126     SkOpAngle* fNext;
    127     SkOpSpan* fLastMarked;
    128     SkDVector fSweep[2];
    129     int fStart;
    130     int fEnd;
    131     int fComputedEnd;
    132     int fSectorMask;
    133     int8_t fSectorStart;  // in 32nds of a circle
    134     int8_t fSectorEnd;
    135     bool fIsCurve;
    136     bool fStop; // set if ordered angle is greater than the previous
    137     mutable bool fUnorderable;  // this is editable by orderable()
    138     bool fUnorderedSweep;  // set when a cubic's first control point between the sweep vectors
    139     bool fComputeSector;
    140     bool fComputedSector;
    141 
    142 #if DEBUG_ANGLE
    143     int fID;
    144 #endif
    145 #if DEBUG_VALIDATE
    146     void debugValidateNext() const;  // in debug builds, verify that angle loop is uncorrupted
    147 #else
    148     void debugValidateNext() const {}
    149 #endif
    150     void dumpOne(bool showFunc) const;  // available to testing only
    151     void dumpPartials() const;  // utility to be called by user from debugger
    152     friend class PathOpsAngleTester;
    153 };
    154 
    155 class SkOpAngleSet {
    156 public:
    157     SkOpAngleSet();
    158     ~SkOpAngleSet();
    159     SkOpAngle& push_back();
    160     void reset();
    161 private:
    162     void dump() const;  // utility to be called by user from debugger
    163     SkChunkAlloc* fAngles;
    164 #if DEBUG_ANGLE
    165     int fCount;
    166 #endif
    167 };
    168 
    169 #endif
    170