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      1 /*
      2  * Copyright 2013 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 #include "PathOpsTestCommon.h"
      8 #include "SkIntersections.h"
      9 #include "SkOpContour.h"
     10 #include "SkOpSegment.h"
     11 #include "SkRandom.h"
     12 #include "SkTArray.h"
     13 #include "SkTSort.h"
     14 #include "Test.h"
     15 
     16 static bool gPathOpsAngleIdeasVerbose = false;
     17 static bool gPathOpsAngleIdeasEnableBruteCheck = false;
     18 
     19 class PathOpsAngleTester {
     20 public:
     21     static int ConvexHullOverlaps(SkOpAngle& lh, SkOpAngle& rh) {
     22         return lh.convexHullOverlaps(&rh);
     23     }
     24 
     25     static int EndsIntersect(SkOpAngle& lh, SkOpAngle& rh) {
     26         return lh.endsIntersect(&rh);
     27     }
     28 };
     29 
     30 struct TRange {
     31     double tMin1;
     32     double tMin2;
     33     double t1;
     34     double t2;
     35     double tMin;
     36     double a1;
     37     double a2;
     38     bool ccw;
     39 };
     40 
     41 static double testArc(skiatest::Reporter* reporter, const SkDQuad& quad, const SkDQuad& arcRef,
     42         int octant) {
     43     SkDQuad arc = arcRef;
     44     SkDVector offset = {quad[0].fX, quad[0].fY};
     45     arc[0] += offset;
     46     arc[1] += offset;
     47     arc[2] += offset;
     48     SkIntersections i;
     49     i.intersect(arc, quad);
     50     if (i.used() == 0) {
     51         return -1;
     52     }
     53     int smallest = -1;
     54     double t = 2;
     55     for (int idx = 0; idx < i.used(); ++idx) {
     56         if (i[0][idx] > 1 || i[0][idx] < 0) {
     57             i.reset();
     58             i.intersect(arc, quad);
     59         }
     60         if (i[1][idx] > 1 || i[1][idx] < 0) {
     61             i.reset();
     62             i.intersect(arc, quad);
     63         }
     64         if (t > i[1][idx]) {
     65             smallest = idx;
     66             t = i[1][idx];
     67         }
     68     }
     69     REPORTER_ASSERT(reporter, smallest >= 0);
     70     REPORTER_ASSERT(reporter, t >= 0 && t <= 1);
     71     return i[1][smallest];
     72 }
     73 
     74 static void orderQuads(skiatest::Reporter* reporter, const SkDQuad& quad, double radius,
     75         SkTArray<double, false>* tArray) {
     76     double r = radius;
     77     double s = r * SK_ScalarTanPIOver8;
     78     double m = r * SK_ScalarRoot2Over2;
     79     // construct circle from quads
     80     const QuadPts circle[8] = {{{{ r,  0}, { r, -s}, { m, -m}}},
     81                                 {{{ m, -m}, { s, -r}, { 0, -r}}},
     82                                 {{{ 0, -r}, {-s, -r}, {-m, -m}}},
     83                                 {{{-m, -m}, {-r, -s}, {-r,  0}}},
     84                                 {{{-r,  0}, {-r,  s}, {-m,  m}}},
     85                                 {{{-m,  m}, {-s,  r}, { 0,  r}}},
     86                                 {{{ 0,  r}, { s,  r}, { m,  m}}},
     87                                 {{{ m,  m}, { r,  s}, { r,  0}}}};
     88     for (int octant = 0; octant < 8; ++octant) {
     89         SkDQuad cQuad;
     90         cQuad.debugSet(circle[octant].fPts);
     91         double t = testArc(reporter, quad, cQuad, octant);
     92         if (t < 0) {
     93             continue;
     94         }
     95         for (int index = 0; index < tArray->count(); ++index) {
     96             double matchT = (*tArray)[index];
     97             if (approximately_equal(t, matchT)) {
     98                 goto next;
     99             }
    100         }
    101         tArray->push_back(t);
    102 next:   ;
    103     }
    104 }
    105 
    106 static double quadAngle(skiatest::Reporter* reporter, const SkDQuad& quad, double t) {
    107     const SkDVector& pt = quad.ptAtT(t) - quad[0];
    108     double angle = (atan2(pt.fY, pt.fX) + SK_ScalarPI) * 8 / (SK_ScalarPI * 2);
    109     REPORTER_ASSERT(reporter, angle >= 0 && angle <= 8);
    110     return angle;
    111 }
    112 
    113 static bool angleDirection(double a1, double a2) {
    114     double delta = a1 - a2;
    115     return (delta < 4 && delta > 0) || delta < -4;
    116 }
    117 
    118 static void setQuadHullSweep(const SkDQuad& quad, SkDVector sweep[2]) {
    119     sweep[0] = quad[1] - quad[0];
    120     sweep[1] = quad[2] - quad[0];
    121 }
    122 
    123 static double distEndRatio(double dist, const SkDQuad& quad) {
    124     SkDVector v[] = {quad[2] - quad[0], quad[1] - quad[0], quad[2] - quad[1]};
    125     double longest = SkTMax(v[0].length(), SkTMax(v[1].length(), v[2].length()));
    126     return longest / dist;
    127 }
    128 
    129 static bool checkParallel(skiatest::Reporter* reporter, const SkDQuad& quad1, const SkDQuad& quad2) {
    130     SkDVector sweep[2], tweep[2];
    131     setQuadHullSweep(quad1, sweep);
    132     setQuadHullSweep(quad2, tweep);
    133     // if the ctrl tangents are not nearly parallel, use them
    134     // solve for opposite direction displacement scale factor == m
    135     // initial dir = v1.cross(v2) == v2.x * v1.y - v2.y * v1.x
    136     // displacement of q1[1] : dq1 = { -m * v1.y, m * v1.x } + q1[1]
    137     // straight angle when : v2.x * (dq1.y - q1[0].y) == v2.y * (dq1.x - q1[0].x)
    138     //                       v2.x * (m * v1.x + v1.y) == v2.y * (-m * v1.y + v1.x)
    139     // - m * (v2.x * v1.x + v2.y * v1.y) == v2.x * v1.y - v2.y * v1.x
    140     // m = (v2.y * v1.x - v2.x * v1.y) / (v2.x * v1.x + v2.y * v1.y)
    141     // m = v1.cross(v2) / v1.dot(v2)
    142     double s0dt0 = sweep[0].dot(tweep[0]);
    143     REPORTER_ASSERT(reporter, s0dt0 != 0);
    144     double s0xt0 = sweep[0].crossCheck(tweep[0]);
    145     double m = s0xt0 / s0dt0;
    146     double sDist = sweep[0].length() * m;
    147     double tDist = tweep[0].length() * m;
    148     bool useS = fabs(sDist) < fabs(tDist);
    149     double mFactor = fabs(useS ? distEndRatio(sDist, quad1) : distEndRatio(tDist, quad2));
    150     if (mFactor < 5000) {  // empirically found limit
    151         return s0xt0 < 0;
    152     }
    153     SkDVector m0 = quad1.ptAtT(0.5) - quad1[0];
    154     SkDVector m1 = quad2.ptAtT(0.5) - quad2[0];
    155     return m0.crossCheck(m1) < 0;
    156 }
    157 
    158 /* returns
    159    -1 if overlaps
    160     0 if no overlap cw
    161     1 if no overlap ccw
    162 */
    163 static int quadHullsOverlap(skiatest::Reporter* reporter, const SkDQuad& quad1,
    164         const SkDQuad& quad2) {
    165     SkDVector sweep[2], tweep[2];
    166     setQuadHullSweep(quad1, sweep);
    167     setQuadHullSweep(quad2, tweep);
    168     double s0xs1 = sweep[0].crossCheck(sweep[1]);
    169     double s0xt0 = sweep[0].crossCheck(tweep[0]);
    170     double s1xt0 = sweep[1].crossCheck(tweep[0]);
    171     bool tBetweenS = s0xs1 > 0 ? s0xt0 > 0 && s1xt0 < 0 : s0xt0 < 0 && s1xt0 > 0;
    172     double s0xt1 = sweep[0].crossCheck(tweep[1]);
    173     double s1xt1 = sweep[1].crossCheck(tweep[1]);
    174     tBetweenS |= s0xs1 > 0 ? s0xt1 > 0 && s1xt1 < 0 : s0xt1 < 0 && s1xt1 > 0;
    175     double t0xt1 = tweep[0].crossCheck(tweep[1]);
    176     if (tBetweenS) {
    177         return -1;
    178     }
    179     if ((s0xt0 == 0 && s1xt1 == 0) || (s1xt0 == 0 && s0xt1 == 0)) {  // s0 to s1 equals t0 to t1
    180         return -1;
    181     }
    182     bool sBetweenT = t0xt1 > 0 ? s0xt0 < 0 && s0xt1 > 0 : s0xt0 > 0 && s0xt1 < 0;
    183     sBetweenT |= t0xt1 > 0 ? s1xt0 < 0 && s1xt1 > 0 : s1xt0 > 0 && s1xt1 < 0;
    184     if (sBetweenT) {
    185         return -1;
    186     }
    187     // if all of the sweeps are in the same half plane, then the order of any pair is enough
    188     if (s0xt0 >= 0 && s0xt1 >= 0 && s1xt0 >= 0 && s1xt1 >= 0) {
    189         return 0;
    190     }
    191     if (s0xt0 <= 0 && s0xt1 <= 0 && s1xt0 <= 0 && s1xt1 <= 0) {
    192         return 1;
    193     }
    194     // if the outside sweeps are greater than 180 degress:
    195         // first assume the inital tangents are the ordering
    196         // if the midpoint direction matches the inital order, that is enough
    197     SkDVector m0 = quad1.ptAtT(0.5) - quad1[0];
    198     SkDVector m1 = quad2.ptAtT(0.5) - quad2[0];
    199     double m0xm1 = m0.crossCheck(m1);
    200     if (s0xt0 > 0 && m0xm1 > 0) {
    201         return 0;
    202     }
    203     if (s0xt0 < 0 && m0xm1 < 0) {
    204         return 1;
    205     }
    206     REPORTER_ASSERT(reporter, s0xt0 != 0);
    207     return checkParallel(reporter, quad1, quad2);
    208 }
    209 
    210 static double radianSweep(double start, double end) {
    211     double sweep = end - start;
    212     if (sweep > SK_ScalarPI) {
    213         sweep -= 2 * SK_ScalarPI;
    214     } else if (sweep < -SK_ScalarPI) {
    215         sweep += 2 * SK_ScalarPI;
    216     }
    217     return sweep;
    218 }
    219 
    220 static bool radianBetween(double start, double test, double end) {
    221     double startToEnd = radianSweep(start, end);
    222     double startToTest = radianSweep(start, test);
    223     double testToEnd = radianSweep(test, end);
    224     return (startToTest <= 0 && testToEnd <= 0 && startToTest >= startToEnd) ||
    225         (startToTest >= 0 && testToEnd >= 0 && startToTest <= startToEnd);
    226 }
    227 
    228 static bool orderTRange(skiatest::Reporter* reporter, const SkDQuad& quad1, const SkDQuad& quad2,
    229         double r, TRange* result) {
    230     SkTArray<double, false> t1Array, t2Array;
    231     orderQuads(reporter, quad1, r, &t1Array);
    232     orderQuads(reporter,quad2, r, &t2Array);
    233     if (!t1Array.count() || !t2Array.count()) {
    234         return false;
    235     }
    236     SkTQSort<double>(t1Array.begin(), t1Array.end() - 1);
    237     SkTQSort<double>(t2Array.begin(), t2Array.end() - 1);
    238     double t1 = result->tMin1 = t1Array[0];
    239     double t2 = result->tMin2 = t2Array[0];
    240     double a1 = quadAngle(reporter,quad1, t1);
    241     double a2 = quadAngle(reporter,quad2, t2);
    242     if (approximately_equal(a1, a2)) {
    243         return false;
    244     }
    245     bool refCCW = angleDirection(a1, a2);
    246     result->t1 = t1;
    247     result->t2 = t2;
    248     result->tMin = SkTMin(t1, t2);
    249     result->a1 = a1;
    250     result->a2 = a2;
    251     result->ccw = refCCW;
    252     return true;
    253 }
    254 
    255 static bool equalPoints(const SkDPoint& pt1, const SkDPoint& pt2, double max) {
    256     return approximately_zero_when_compared_to(pt1.fX - pt2.fX, max)
    257             && approximately_zero_when_compared_to(pt1.fY - pt2.fY, max);
    258 }
    259 
    260 static double maxDist(const SkDQuad& quad) {
    261     SkDRect bounds;
    262     bounds.setBounds(quad);
    263     SkDVector corner[4] = {
    264         { bounds.fLeft - quad[0].fX, bounds.fTop - quad[0].fY },
    265         { bounds.fRight - quad[0].fX, bounds.fTop - quad[0].fY },
    266         { bounds.fLeft - quad[0].fX, bounds.fBottom - quad[0].fY },
    267         { bounds.fRight - quad[0].fX, bounds.fBottom - quad[0].fY }
    268     };
    269     double max = 0;
    270     for (unsigned index = 0; index < SK_ARRAY_COUNT(corner); ++index) {
    271         max = SkTMax(max, corner[index].length());
    272     }
    273     return max;
    274 }
    275 
    276 static double maxQuad(const SkDQuad& quad) {
    277     double max = 0;
    278     for (int index = 0; index < 2; ++index) {
    279         max = SkTMax(max, fabs(quad[index].fX));
    280         max = SkTMax(max, fabs(quad[index].fY));
    281     }
    282     return max;
    283 }
    284 
    285 static bool bruteMinT(skiatest::Reporter* reporter, const SkDQuad& quad1, const SkDQuad& quad2,
    286         TRange* lowerRange, TRange* upperRange) {
    287     double maxRadius = SkTMin(maxDist(quad1), maxDist(quad2));
    288     double maxQuads = SkTMax(maxQuad(quad1), maxQuad(quad2));
    289     double r = maxRadius / 2;
    290     double rStep = r / 2;
    291     SkDPoint best1 = {SK_ScalarInfinity, SK_ScalarInfinity};
    292     SkDPoint best2 = {SK_ScalarInfinity, SK_ScalarInfinity};
    293     int bestCCW = -1;
    294     double bestR = maxRadius;
    295     upperRange->tMin = 0;
    296     lowerRange->tMin = 1;
    297     do {
    298         do {  // find upper bounds of single result
    299             TRange tRange;
    300             bool stepUp = orderTRange(reporter, quad1, quad2, r, &tRange);
    301             if (stepUp) {
    302                 SkDPoint pt1 = quad1.ptAtT(tRange.t1);
    303                 if (equalPoints(pt1, best1, maxQuads)) {
    304                     break;
    305                 }
    306                 best1 = pt1;
    307                 SkDPoint pt2 = quad2.ptAtT(tRange.t2);
    308                 if (equalPoints(pt2, best2, maxQuads)) {
    309                     break;
    310                 }
    311                 best2 = pt2;
    312                 if (gPathOpsAngleIdeasVerbose) {
    313                     SkDebugf("u bestCCW=%d ccw=%d bestMin=%1.9g:%1.9g r=%1.9g tMin=%1.9g\n",
    314                             bestCCW, tRange.ccw, lowerRange->tMin, upperRange->tMin, r,
    315                             tRange.tMin);
    316                 }
    317                 if (bestCCW >= 0 && bestCCW != (int) tRange.ccw) {
    318                     if (tRange.tMin < upperRange->tMin) {
    319                         upperRange->tMin = 0;
    320                     } else {
    321                         stepUp = false;
    322                     }
    323                 }
    324                 if (upperRange->tMin < tRange.tMin) {
    325                     bestCCW = tRange.ccw;
    326                     bestR = r;
    327                     *upperRange = tRange;
    328                 }
    329                 if (lowerRange->tMin > tRange.tMin) {
    330                     *lowerRange = tRange;
    331                 }
    332             }
    333             r += stepUp ? rStep : -rStep;
    334             rStep /= 2;
    335         } while (rStep > FLT_EPSILON);
    336         if (bestCCW < 0) {
    337             if (bestR >= maxRadius) {
    338                 SkDebugf("");
    339             }
    340             REPORTER_ASSERT(reporter, bestR < maxRadius);
    341             return false;
    342         }
    343         double lastHighR = bestR;
    344         r = bestR / 2;
    345         rStep = r / 2;
    346         do {  // find lower bounds of single result
    347             TRange tRange;
    348             bool success = orderTRange(reporter, quad1, quad2, r, &tRange);
    349             if (success) {
    350                 if (gPathOpsAngleIdeasVerbose) {
    351                     SkDebugf("l bestCCW=%d ccw=%d bestMin=%1.9g:%1.9g r=%1.9g tMin=%1.9g\n",
    352                             bestCCW, tRange.ccw, lowerRange->tMin, upperRange->tMin, r,
    353                             tRange.tMin);
    354                 }
    355                 if (bestCCW != (int) tRange.ccw || upperRange->tMin < tRange.tMin) {
    356                     bestCCW = tRange.ccw;
    357                     *upperRange = tRange;
    358                     bestR = lastHighR;
    359                     break;  // need to establish a new upper bounds
    360                 }
    361                 SkDPoint pt1 = quad1.ptAtT(tRange.t1);
    362                 SkDPoint pt2 = quad2.ptAtT(tRange.t2);
    363                 if (equalPoints(pt1, best1, maxQuads)) {
    364                     goto breakOut;
    365                 }
    366                 best1 = pt1;
    367                 if (equalPoints(pt2, best2, maxQuads)) {
    368                     goto breakOut;
    369                 }
    370                 best2 = pt2;
    371                 if (equalPoints(pt1, pt2, maxQuads)) {
    372                     success = false;
    373                 } else {
    374                     if (upperRange->tMin < tRange.tMin) {
    375                         *upperRange = tRange;
    376                     }
    377                     if (lowerRange->tMin > tRange.tMin) {
    378                         *lowerRange = tRange;
    379                     }
    380                 }
    381                 lastHighR = SkTMin(r, lastHighR);
    382             }
    383             r += success ? -rStep : rStep;
    384             rStep /= 2;
    385         } while (rStep > FLT_EPSILON);
    386     } while (rStep > FLT_EPSILON);
    387 breakOut:
    388     if (gPathOpsAngleIdeasVerbose) {
    389         SkDebugf("l a2-a1==%1.9g\n", lowerRange->a2 - lowerRange->a1);
    390     }
    391     return true;
    392 }
    393 
    394 static void bruteForce(skiatest::Reporter* reporter, const SkDQuad& quad1, const SkDQuad& quad2,
    395         bool ccw) {
    396     if (!gPathOpsAngleIdeasEnableBruteCheck) {
    397         return;
    398     }
    399     TRange lowerRange, upperRange;
    400     bool result = bruteMinT(reporter, quad1, quad2, &lowerRange, &upperRange);
    401     REPORTER_ASSERT(reporter, result);
    402     double angle = fabs(lowerRange.a2 - lowerRange.a1);
    403     REPORTER_ASSERT(reporter, angle > 3.998 || ccw == upperRange.ccw);
    404 }
    405 
    406 static bool bruteForceCheck(skiatest::Reporter* reporter, const SkDQuad& quad1,
    407         const SkDQuad& quad2, bool ccw) {
    408     TRange lowerRange, upperRange;
    409     bool result = bruteMinT(reporter, quad1, quad2, &lowerRange, &upperRange);
    410     REPORTER_ASSERT(reporter, result);
    411     return ccw == upperRange.ccw;
    412 }
    413 
    414 static void makeSegment(SkOpContour* contour, const SkDQuad& quad, SkPoint shortQuad[3]) {
    415     shortQuad[0] = quad[0].asSkPoint();
    416     shortQuad[1] = quad[1].asSkPoint();
    417     shortQuad[2] = quad[2].asSkPoint();
    418     contour->addQuad(shortQuad);
    419 }
    420 
    421 static void testQuadAngles(skiatest::Reporter* reporter, const SkDQuad& quad1, const SkDQuad& quad2,
    422         int testNo, SkArenaAlloc* allocator) {
    423     SkPoint shortQuads[2][3];
    424 
    425     SkOpContourHead contour;
    426     SkOpGlobalState state(&contour, allocator  SkDEBUGPARAMS(false) SkDEBUGPARAMS(nullptr));
    427     contour.init(&state, false, false);
    428     makeSegment(&contour, quad1, shortQuads[0]);
    429     makeSegment(&contour, quad1, shortQuads[1]);
    430     SkOpSegment* seg1 = contour.first();
    431     seg1->debugAddAngle(0, 1);
    432     SkOpSegment* seg2 = seg1->next();
    433     seg2->debugAddAngle(0, 1);
    434     int realOverlap = PathOpsAngleTester::ConvexHullOverlaps(*seg1->debugLastAngle(),
    435             *seg2->debugLastAngle());
    436     const SkDPoint& origin = quad1[0];
    437     REPORTER_ASSERT(reporter, origin == quad2[0]);
    438     double a1s = atan2(origin.fY - quad1[1].fY, quad1[1].fX - origin.fX);
    439     double a1e = atan2(origin.fY - quad1[2].fY, quad1[2].fX - origin.fX);
    440     double a2s = atan2(origin.fY - quad2[1].fY, quad2[1].fX - origin.fX);
    441     double a2e = atan2(origin.fY - quad2[2].fY, quad2[2].fX - origin.fX);
    442     bool oldSchoolOverlap = radianBetween(a1s, a2s, a1e)
    443         || radianBetween(a1s, a2e, a1e) || radianBetween(a2s, a1s, a2e)
    444         || radianBetween(a2s, a1e, a2e);
    445     int overlap = quadHullsOverlap(reporter, quad1, quad2);
    446     bool realMatchesOverlap = realOverlap == overlap || SK_ScalarPI - fabs(a2s - a1s) < 0.002;
    447     if (realOverlap != overlap) {
    448         SkDebugf("\nSK_ScalarPI - fabs(a2s - a1s) = %1.9g\n", SK_ScalarPI - fabs(a2s - a1s));
    449     }
    450     if (!realMatchesOverlap) {
    451         DumpQ(quad1, quad2, testNo);
    452     }
    453     REPORTER_ASSERT(reporter, realMatchesOverlap);
    454     if (oldSchoolOverlap != (overlap < 0)) {
    455         overlap = quadHullsOverlap(reporter, quad1, quad2);  // set a breakpoint and debug if assert fires
    456         REPORTER_ASSERT(reporter, oldSchoolOverlap == (overlap < 0));
    457     }
    458     SkDVector v1s = quad1[1] - quad1[0];
    459     SkDVector v1e = quad1[2] - quad1[0];
    460     SkDVector v2s = quad2[1] - quad2[0];
    461     SkDVector v2e = quad2[2] - quad2[0];
    462     double vDir[2] = { v1s.cross(v1e), v2s.cross(v2e) };
    463     bool ray1In2 = v1s.cross(v2s) * vDir[1] <= 0 && v1s.cross(v2e) * vDir[1] >= 0;
    464     bool ray2In1 = v2s.cross(v1s) * vDir[0] <= 0 && v2s.cross(v1e) * vDir[0] >= 0;
    465     if (overlap >= 0) {
    466         // verify that hulls really don't overlap
    467         REPORTER_ASSERT(reporter, !ray1In2);
    468         REPORTER_ASSERT(reporter, !ray2In1);
    469         bool ctrl1In2 = v1e.cross(v2s) * vDir[1] <= 0 && v1e.cross(v2e) * vDir[1] >= 0;
    470         REPORTER_ASSERT(reporter, !ctrl1In2);
    471         bool ctrl2In1 = v2e.cross(v1s) * vDir[0] <= 0 && v2e.cross(v1e) * vDir[0] >= 0;
    472         REPORTER_ASSERT(reporter, !ctrl2In1);
    473         // check answer against reference
    474         bruteForce(reporter, quad1, quad2, overlap > 0);
    475     }
    476     // continue end point rays and see if they intersect the opposite curve
    477     SkDLine rays[] = {{{origin, quad2[2]}}, {{origin, quad1[2]}}};
    478     const SkDQuad* quads[] = {&quad1, &quad2};
    479     SkDVector midSpokes[2];
    480     SkIntersections intersect[2];
    481     double minX, minY, maxX, maxY;
    482     minX = minY = SK_ScalarInfinity;
    483     maxX = maxY = -SK_ScalarInfinity;
    484     double maxWidth = 0;
    485     bool useIntersect = false;
    486     double smallestTs[] = {1, 1};
    487     for (unsigned index = 0; index < SK_ARRAY_COUNT(quads); ++index) {
    488         const SkDQuad& q = *quads[index];
    489         midSpokes[index] = q.ptAtT(0.5) - origin;
    490         minX = SkTMin(SkTMin(SkTMin(minX, origin.fX), q[1].fX), q[2].fX);
    491         minY = SkTMin(SkTMin(SkTMin(minY, origin.fY), q[1].fY), q[2].fY);
    492         maxX = SkTMax(SkTMax(SkTMax(maxX, origin.fX), q[1].fX), q[2].fX);
    493         maxY = SkTMax(SkTMax(SkTMax(maxY, origin.fY), q[1].fY), q[2].fY);
    494         maxWidth = SkTMax(maxWidth, SkTMax(maxX - minX, maxY - minY));
    495         intersect[index].intersectRay(q, rays[index]);
    496         const SkIntersections& i = intersect[index];
    497         REPORTER_ASSERT(reporter, i.used() >= 1);
    498         bool foundZero = false;
    499         double smallT = 1;
    500         for (int idx2 = 0; idx2 < i.used(); ++idx2) {
    501             double t = i[0][idx2];
    502             if (t == 0) {
    503                 foundZero = true;
    504                 continue;
    505             }
    506             if (smallT > t) {
    507                 smallT = t;
    508             }
    509         }
    510         REPORTER_ASSERT(reporter, foundZero == true);
    511         if (smallT == 1) {
    512             continue;
    513         }
    514         SkDVector ray = q.ptAtT(smallT) - origin;
    515         SkDVector end = rays[index][1] - origin;
    516         if (ray.fX * end.fX < 0 || ray.fY * end.fY < 0) {
    517             continue;
    518         }
    519         double rayDist = ray.length();
    520         double endDist = end.length();
    521         double delta = fabs(rayDist - endDist) / maxWidth;
    522         if (delta > 1e-4) {
    523             useIntersect ^= true;
    524         }
    525         smallestTs[index] = smallT;
    526     }
    527     bool firstInside;
    528     if (useIntersect) {
    529         int sIndex = (int) (smallestTs[1] < 1);
    530         REPORTER_ASSERT(reporter, smallestTs[sIndex ^ 1] == 1);
    531         double t = smallestTs[sIndex];
    532         const SkDQuad& q = *quads[sIndex];
    533         SkDVector ray = q.ptAtT(t) - origin;
    534         SkDVector end = rays[sIndex][1] - origin;
    535         double rayDist = ray.length();
    536         double endDist = end.length();
    537         SkDVector mid = q.ptAtT(t / 2) - origin;
    538         double midXray = mid.crossCheck(ray);
    539         if (gPathOpsAngleIdeasVerbose) {
    540             SkDebugf("rayDist>endDist:%d sIndex==0:%d vDir[sIndex]<0:%d midXray<0:%d\n",
    541                     rayDist > endDist, sIndex == 0, vDir[sIndex] < 0, midXray < 0);
    542         }
    543         SkASSERT(SkScalarSignAsInt(SkDoubleToScalar(midXray))
    544             == SkScalarSignAsInt(SkDoubleToScalar(vDir[sIndex])));
    545         firstInside = (rayDist > endDist) ^ (sIndex == 0) ^ (vDir[sIndex] < 0);
    546     } else if (overlap >= 0) {
    547         return;  // answer has already been determined
    548     } else {
    549         firstInside = checkParallel(reporter, quad1, quad2);
    550     }
    551     if (overlap < 0) {
    552         SkDEBUGCODE(int realEnds =)
    553                 PathOpsAngleTester::EndsIntersect(*seg1->debugLastAngle(),
    554                 *seg2->debugLastAngle());
    555         SkASSERT(realEnds == (firstInside ? 1 : 0));
    556     }
    557     bruteForce(reporter, quad1, quad2, firstInside);
    558 }
    559 
    560 DEF_TEST(PathOpsAngleOverlapHullsOne, reporter) {
    561     SkSTArenaAlloc<4096> allocator;
    562 //    gPathOpsAngleIdeasVerbose = true;
    563     const QuadPts quads[] = {
    564 {{{939.4808349609375, 914.355224609375}, {-357.7921142578125, 590.842529296875}, {736.8936767578125, -350.717529296875}}},
    565 {{{939.4808349609375, 914.355224609375}, {-182.85418701171875, 634.4552001953125}, {-509.62615966796875, 576.1182861328125}}}
    566     };
    567     for (int index = 0; index < (int) SK_ARRAY_COUNT(quads); index += 2) {
    568         SkDQuad quad0, quad1;
    569         quad0.debugSet(quads[index].fPts);
    570         quad1.debugSet(quads[index + 1].fPts);
    571         testQuadAngles(reporter, quad0, quad1, 0, &allocator);
    572     }
    573 }
    574 
    575 DEF_TEST(PathOpsAngleOverlapHulls, reporter) {
    576     SkSTArenaAlloc<4096> allocator;
    577     if (!gPathOpsAngleIdeasVerbose) {  // takes a while to run -- so exclude it by default
    578         return;
    579     }
    580     SkRandom ran;
    581     for (int index = 0; index < 100000; ++index) {
    582         if (index % 1000 == 999) SkDebugf(".");
    583         SkDPoint origin = {ran.nextRangeF(-1000, 1000), ran.nextRangeF(-1000, 1000)};
    584         QuadPts quad1 = {{origin, {ran.nextRangeF(-1000, 1000), ran.nextRangeF(-1000, 1000)},
    585             {ran.nextRangeF(-1000, 1000), ran.nextRangeF(-1000, 1000)}}};
    586         if (quad1.fPts[0] == quad1.fPts[2]) {
    587             continue;
    588         }
    589         QuadPts quad2 = {{origin, {ran.nextRangeF(-1000, 1000), ran.nextRangeF(-1000, 1000)},
    590             {ran.nextRangeF(-1000, 1000), ran.nextRangeF(-1000, 1000)}}};
    591         if (quad2.fPts[0] == quad2.fPts[2]) {
    592             continue;
    593         }
    594         SkIntersections i;
    595         SkDQuad q1, q2;
    596         q1.debugSet(quad1.fPts);
    597         q2.debugSet(quad2.fPts);
    598         i.intersect(q1, q2);
    599         REPORTER_ASSERT(reporter, i.used() >= 1);
    600         if (i.used() > 1) {
    601             continue;
    602         }
    603         testQuadAngles(reporter, q1, q2, index, &allocator);
    604     }
    605 }
    606 
    607 DEF_TEST(PathOpsAngleBruteT, reporter) {
    608     if (!gPathOpsAngleIdeasVerbose) {  // takes a while to run -- so exclude it by default
    609         return;
    610     }
    611     SkRandom ran;
    612     double smaller = SK_Scalar1;
    613     SkDQuad small[2];
    614     SkDEBUGCODE(int smallIndex = 0);
    615     for (int index = 0; index < 100000; ++index) {
    616         SkDPoint origin = {ran.nextRangeF(-1000, 1000), ran.nextRangeF(-1000, 1000)};
    617         QuadPts quad1 = {{origin, {ran.nextRangeF(-1000, 1000), ran.nextRangeF(-1000, 1000)},
    618             {ran.nextRangeF(-1000, 1000), ran.nextRangeF(-1000, 1000)}}};
    619         if (quad1.fPts[0] == quad1.fPts[2]) {
    620             continue;
    621         }
    622         QuadPts quad2 = {{origin, {ran.nextRangeF(-1000, 1000), ran.nextRangeF(-1000, 1000)},
    623             {ran.nextRangeF(-1000, 1000), ran.nextRangeF(-1000, 1000)}}};
    624         if (quad2.fPts[0] == quad2.fPts[2]) {
    625             continue;
    626         }
    627         SkDQuad q1, q2;
    628         q1.debugSet(quad1.fPts);
    629         q2.debugSet(quad2.fPts);
    630         SkIntersections i;
    631         i.intersect(q1, q2);
    632         REPORTER_ASSERT(reporter, i.used() >= 1);
    633         if (i.used() > 1) {
    634             continue;
    635         }
    636         TRange lowerRange, upperRange;
    637         bool result = bruteMinT(reporter, q1, q2, &lowerRange, &upperRange);
    638         REPORTER_ASSERT(reporter, result);
    639         double min = SkTMin(upperRange.t1, upperRange.t2);
    640         if (smaller > min) {
    641             small[0] = q1;
    642             small[1] = q2;
    643             SkDEBUGCODE(smallIndex = index);
    644             smaller = min;
    645         }
    646     }
    647 #ifdef SK_DEBUG
    648     DumpQ(small[0], small[1], smallIndex);
    649 #endif
    650 }
    651 
    652 DEF_TEST(PathOpsAngleBruteTOne, reporter) {
    653 //    gPathOpsAngleIdeasVerbose = true;
    654     const QuadPts qPts[] = {
    655 {{{-770.8492431640625, 948.2369384765625}, {-853.37066650390625, 972.0301513671875}, {-200.62042236328125, -26.7174072265625}}},
    656 {{{-770.8492431640625, 948.2369384765625}, {513.602783203125, 578.8681640625}, {960.641357421875, -813.69757080078125}}},
    657 {{{563.8267822265625, -107.4566650390625}, {-44.67724609375, -136.57452392578125}, {492.3856201171875, -268.79644775390625}}},
    658 {{{563.8267822265625, -107.4566650390625}, {708.049072265625, -100.77789306640625}, {-48.88226318359375, 967.9022216796875}}},
    659 {{{598.857421875, 846.345458984375}, {-644.095703125, -316.12921142578125}, {-97.64599609375, 20.6158447265625}}},
    660 {{{598.857421875, 846.345458984375}, {715.7142333984375, 955.3599853515625}, {-919.9478759765625, 691.611328125}}},
    661     };
    662     TRange lowerRange, upperRange;
    663     SkDQuad quads[SK_ARRAY_COUNT(qPts)];
    664     for (int index = 0; index < (int) SK_ARRAY_COUNT(qPts); ++index) {
    665         quads[index].debugSet(qPts[index].fPts);
    666     }
    667     bruteMinT(reporter, quads[0], quads[1], &lowerRange, &upperRange);
    668     bruteMinT(reporter, quads[2], quads[3], &lowerRange, &upperRange);
    669     bruteMinT(reporter, quads[4], quads[5], &lowerRange, &upperRange);
    670 }
    671 
    672 /*
    673 The sorting problem happens when the inital tangents are not a true indicator of the curve direction
    674 Nearly always, the initial tangents do give the right answer,
    675 so the trick is to figure out when the initial tangent cannot be trusted.
    676 If the convex hulls of both curves are in the same half plane, and not overlapping, sorting the
    677 hulls is enough.
    678 If the hulls overlap, and have the same general direction, then intersect the shorter end point ray
    679 with the opposing curve, and see on which side of the shorter curve the opposing intersection lies.
    680 Otherwise, if the control vector is extremely short, likely the point on curve must be computed
    681 If moving the control point slightly can change the sign of the cross product, either answer could
    682 be "right".
    683 We need to determine how short is extremely short. Move the control point a set percentage of
    684 the largest length to determine how stable the curve is vis-a-vis the initial tangent.
    685 */
    686 
    687 static const QuadPts extremeTests[][2] = {
    688     {
    689         {{{-708.0077926931004,-154.61669472244046},
    690             {-707.9234268635319,-154.30459999551294},
    691             {505.58447265625,-504.9130859375}}},
    692         {{{-708.0077926931004,-154.61669472244046},
    693             {-711.127526325141,-163.9446090624656},
    694             {-32.39227294921875,-906.3277587890625}}},
    695     }, {
    696         {{{-708.0077926931004,-154.61669472244046},
    697             {-708.2875337527566,-154.36676458635623},
    698             {505.58447265625,-504.9130859375}}},
    699         {{{-708.0077926931004,-154.61669472244046},
    700             {-708.4111557216864,-154.5366642875255},
    701             {-32.39227294921875,-906.3277587890625}}},
    702     }, {
    703         {{{-609.0230951752058,-267.5435593490574},
    704             {-594.1120809906336,-136.08492475411555},
    705             {505.58447265625,-504.9130859375}}},
    706         {{{-609.0230951752058,-267.5435593490574},
    707             {-693.7467719138988,-341.3259237831895},
    708             {-32.39227294921875,-906.3277587890625}}}
    709     }, {
    710         {{{-708.0077926931004,-154.61669472244046},
    711             {-707.9994640658723,-154.58588461064852},
    712             {505.58447265625,-504.9130859375}}},
    713         {{{-708.0077926931004,-154.61669472244046},
    714             {-708.0239418990758,-154.6403553507124},
    715             {-32.39227294921875,-906.3277587890625}}}
    716     }, {
    717         {{{-708.0077926931004,-154.61669472244046},
    718             {-707.9993222215099,-154.55999389855003},
    719             {68.88981098017803,296.9273945411635}}},
    720         {{{-708.0077926931004,-154.61669472244046},
    721             {-708.0509091919608,-154.64675214697067},
    722             {-777.4871194247767,-995.1470120113145}}}
    723     }, {
    724         {{{-708.0077926931004,-154.61669472244046},
    725             {-708.0060491116379,-154.60889321524968},
    726             {229.97088707895057,-430.0569357467175}}},
    727         {{{-708.0077926931004,-154.61669472244046},
    728             {-708.013911296257,-154.6219143988058},
    729             {138.13162892614037,-573.3689311737394}}}
    730     }, {
    731         {{{-543.2570545751013,-237.29243831075053},
    732             {-452.4119186056987,-143.47223056267802},
    733             {229.97088707895057,-430.0569357467175}}},
    734         {{{-543.2570545751013,-237.29243831075053},
    735             {-660.5330371214436,-362.0016148388},
    736             {138.13162892614037,-573.3689311737394}}},
    737     },
    738 };
    739 
    740 static double endCtrlRatio(const SkDQuad quad) {
    741     SkDVector longEdge = quad[2] - quad[0];
    742     double longLen = longEdge.length();
    743     SkDVector shortEdge = quad[1] - quad[0];
    744     double shortLen = shortEdge.length();
    745     return longLen / shortLen;
    746 }
    747 
    748 static void computeMV(const SkDQuad& quad, const SkDVector& v, double m, SkDVector mV[2]) {
    749         SkDPoint mPta = {quad[1].fX - m * v.fY, quad[1].fY + m * v.fX};
    750         SkDPoint mPtb = {quad[1].fX + m * v.fY, quad[1].fY - m * v.fX};
    751         mV[0] = mPta - quad[0];
    752         mV[1] = mPtb - quad[0];
    753 }
    754 
    755 static double mDistance(skiatest::Reporter* reporter, bool agrees, const SkDQuad& q1,
    756         const SkDQuad& q2) {
    757     if (1 && agrees) {
    758         return SK_ScalarMax;
    759     }
    760     // how close is the angle from inflecting in the opposite direction?
    761     SkDVector v1 = q1[1] - q1[0];
    762     SkDVector v2 = q2[1] - q2[0];
    763     double dir = v1.crossCheck(v2);
    764     REPORTER_ASSERT(reporter, dir != 0);
    765     // solve for opposite direction displacement scale factor == m
    766     // initial dir = v1.cross(v2) == v2.x * v1.y - v2.y * v1.x
    767     // displacement of q1[1] : dq1 = { -m * v1.y, m * v1.x } + q1[1]
    768     // straight angle when : v2.x * (dq1.y - q1[0].y) == v2.y * (dq1.x - q1[0].x)
    769     //                       v2.x * (m * v1.x + v1.y) == v2.y * (-m * v1.y + v1.x)
    770     // - m * (v2.x * v1.x + v2.y * v1.y) == v2.x * v1.y - v2.y * v1.x
    771     // m = (v2.y * v1.x - v2.x * v1.y) / (v2.x * v1.x + v2.y * v1.y)
    772     // m = v1.cross(v2) / v1.dot(v2)
    773     double div = v1.dot(v2);
    774     REPORTER_ASSERT(reporter, div != 0);
    775     double m = dir / div;
    776     SkDVector mV1[2], mV2[2];
    777     computeMV(q1, v1, m, mV1);
    778     computeMV(q2, v2, m, mV2);
    779     double dist1 = v1.length() * m;
    780     double dist2 = v2.length() * m;
    781     if (gPathOpsAngleIdeasVerbose) {
    782         SkDebugf("%c r1=%1.9g r2=%1.9g m=%1.9g dist1=%1.9g dist2=%1.9g "
    783                 " dir%c 1a=%1.9g 1b=%1.9g 2a=%1.9g 2b=%1.9g\n", agrees ? 'T' : 'F',
    784                 endCtrlRatio(q1), endCtrlRatio(q2), m, dist1, dist2, dir > 0 ? '+' : '-',
    785                 mV1[0].crossCheck(v2), mV1[1].crossCheck(v2),
    786                 mV2[0].crossCheck(v1), mV2[1].crossCheck(v1));
    787     }
    788     if (1) {
    789         bool use1 = fabs(dist1) < fabs(dist2);
    790         if (gPathOpsAngleIdeasVerbose) {
    791             SkDebugf("%c dist=%1.9g r=%1.9g\n", agrees ? 'T' : 'F', use1 ? dist1 : dist2,
    792                 use1 ? distEndRatio(dist1, q1) : distEndRatio(dist2, q2));
    793         }
    794         return fabs(use1 ? distEndRatio(dist1, q1) : distEndRatio(dist2, q2));
    795     }
    796     return SK_ScalarMax;
    797 }
    798 
    799 static void midPointAgrees(skiatest::Reporter* reporter, const SkDQuad& q1, const SkDQuad& q2,
    800         bool ccw) {
    801     SkDPoint mid1 = q1.ptAtT(0.5);
    802     SkDVector m1 = mid1 - q1[0];
    803     SkDPoint mid2 = q2.ptAtT(0.5);
    804     SkDVector m2 = mid2 - q2[0];
    805     REPORTER_ASSERT(reporter, ccw ? m1.crossCheck(m2) < 0 : m1.crossCheck(m2) > 0);
    806 }
    807 
    808 DEF_TEST(PathOpsAngleExtreme, reporter) {
    809     if (!gPathOpsAngleIdeasVerbose) {  // takes a while to run -- so exclude it by default
    810         return;
    811     }
    812     double maxR = SK_ScalarMax;
    813     for (int index = 0; index < (int) SK_ARRAY_COUNT(extremeTests); ++index) {
    814         const QuadPts& qu1 = extremeTests[index][0];
    815         const QuadPts& qu2 = extremeTests[index][1];
    816         SkDQuad quad1, quad2;
    817         quad1.debugSet(qu1.fPts);
    818         quad2.debugSet(qu2.fPts);
    819         if (gPathOpsAngleIdeasVerbose) {
    820             SkDebugf("%s %d\n", __FUNCTION__, index);
    821         }
    822         REPORTER_ASSERT(reporter, quad1[0] == quad2[0]);
    823         SkIntersections i;
    824         i.intersect(quad1, quad2);
    825         REPORTER_ASSERT(reporter, i.used() == 1);
    826         REPORTER_ASSERT(reporter, i.pt(0) == quad1[0]);
    827         int overlap = quadHullsOverlap(reporter, quad1, quad2);
    828         REPORTER_ASSERT(reporter, overlap >= 0);
    829         SkDVector sweep[2], tweep[2];
    830         setQuadHullSweep(quad1, sweep);
    831         setQuadHullSweep(quad2, tweep);
    832         double s0xt0 = sweep[0].crossCheck(tweep[0]);
    833         REPORTER_ASSERT(reporter, s0xt0 != 0);
    834         bool ccw = s0xt0 < 0;
    835         bool agrees = bruteForceCheck(reporter, quad1, quad2, ccw);
    836         maxR = SkTMin(maxR, mDistance(reporter, agrees, quad1, quad2));
    837         if (agrees) {
    838             continue;
    839         }
    840         midPointAgrees(reporter, quad1, quad2, !ccw);
    841         SkDQuad q1 = quad1;
    842         SkDQuad q2 = quad2;
    843         double loFail = 1;
    844         double hiPass = 2;
    845         // double vectors until t passes
    846         do {
    847             q1[1].fX = quad1[0].fX * (1 - hiPass) + quad1[1].fX * hiPass;
    848             q1[1].fY = quad1[0].fY * (1 - hiPass) + quad1[1].fY * hiPass;
    849             q2[1].fX = quad2[0].fX * (1 - hiPass) + quad2[1].fX * hiPass;
    850             q2[1].fY = quad2[0].fY * (1 - hiPass) + quad2[1].fY * hiPass;
    851             agrees = bruteForceCheck(reporter, q1, q2, ccw);
    852             maxR = SkTMin(maxR, mDistance(reporter, agrees, q1, q2));
    853             if (agrees) {
    854                 break;
    855             }
    856             midPointAgrees(reporter, quad1, quad2, !ccw);
    857             loFail = hiPass;
    858             hiPass *= 2;
    859         } while (true);
    860         // binary search to find minimum pass
    861         double midTest = (loFail + hiPass) / 2;
    862         double step = (hiPass - loFail) / 4;
    863         while (step > FLT_EPSILON) {
    864             q1[1].fX = quad1[0].fX * (1 - midTest) + quad1[1].fX * midTest;
    865             q1[1].fY = quad1[0].fY * (1 - midTest) + quad1[1].fY * midTest;
    866             q2[1].fX = quad2[0].fX * (1 - midTest) + quad2[1].fX * midTest;
    867             q2[1].fY = quad2[0].fY * (1 - midTest) + quad2[1].fY * midTest;
    868             agrees = bruteForceCheck(reporter, q1, q2, ccw);
    869             maxR = SkTMin(maxR, mDistance(reporter, agrees, q1, q2));
    870             if (!agrees) {
    871                 midPointAgrees(reporter, quad1, quad2, !ccw);
    872             }
    873             midTest += agrees ? -step : step;
    874             step /= 2;
    875         }
    876 #ifdef SK_DEBUG
    877 //        DumpQ(q1, q2, 999);
    878 #endif
    879     }
    880     if (gPathOpsAngleIdeasVerbose) {
    881         SkDebugf("maxR=%1.9g\n", maxR);
    882     }
    883 }
    884