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| 1 // Another approach is to start with the implicit form of one curve and solve | |
| 2 // (seek implicit coefficients in QuadraticParameter.cpp | |
| 3 // by substituting in the parametric form of the other. | |
| 4 // The downside of this approach is that early rejects are difficult to come by. | |
| 5 // http://planetmath.org/encyclopedia/GaloisTheoreticDerivationOfTheQuarticFormu
la.html#step | |
| 6 | |
| 7 #include "SkDQuadImplicit.h" | |
| 8 #include "SkIntersections.h" | |
| 9 #include "SkPathOpsLine.h" | |
| 10 #include "SkQuarticRoot.h" | |
| 11 #include "SkTArray.h" | |
| 12 #include "SkTSort.h" | |
| 13 | |
| 14 /* given the implicit form 0 = Ax^2 + Bxy + Cy^2 + Dx + Ey + F | |
| 15 * and given x = at^2 + bt + c (the parameterized form) | |
| 16 * y = dt^2 + et + f | |
| 17 * then | |
| 18 * 0 = A(at^2+bt+c)(at^2+bt+c)+B(at^2+bt+c)(dt^2+et+f)+C(dt^2+et+f)(dt^2+et+f)+D
(at^2+bt+c)+E(dt^2+et+f)+F | |
| 19 */ | |
| 20 | |
| 21 static int findRoots(const SkDQuadImplicit& i, const SkDQuad& quad, double roots
[4], | |
| 22 bool oneHint, bool flip, int firstCubicRoot) { | |
| 23 SkDQuad flipped; | |
| 24 const SkDQuad& q = flip ? (flipped = quad.flip()) : quad; | |
| 25 double a, b, c; | |
| 26 SkDQuad::SetABC(&q[0].fX, &a, &b, &c); | |
| 27 double d, e, f; | |
| 28 SkDQuad::SetABC(&q[0].fY, &d, &e, &f); | |
| 29 const double t4 = i.x2() * a * a | |
| 30 + i.xy() * a * d | |
| 31 + i.y2() * d * d; | |
| 32 const double t3 = 2 * i.x2() * a * b | |
| 33 + i.xy() * (a * e + b * d) | |
| 34 + 2 * i.y2() * d * e; | |
| 35 const double t2 = i.x2() * (b * b + 2 * a * c) | |
| 36 + i.xy() * (c * d + b * e + a * f) | |
| 37 + i.y2() * (e * e + 2 * d * f) | |
| 38 + i.x() * a | |
| 39 + i.y() * d; | |
| 40 const double t1 = 2 * i.x2() * b * c | |
| 41 + i.xy() * (c * e + b * f) | |
| 42 + 2 * i.y2() * e * f | |
| 43 + i.x() * b | |
| 44 + i.y() * e; | |
| 45 const double t0 = i.x2() * c * c | |
| 46 + i.xy() * c * f | |
| 47 + i.y2() * f * f | |
| 48 + i.x() * c | |
| 49 + i.y() * f | |
| 50 + i.c(); | |
| 51 int rootCount = SkReducedQuarticRoots(t4, t3, t2, t1, t0, oneHint, roots); | |
| 52 if (rootCount < 0) { | |
| 53 rootCount = SkQuarticRootsReal(firstCubicRoot, t4, t3, t2, t1, t0, roots
); | |
| 54 } | |
| 55 if (flip) { | |
| 56 for (int index = 0; index < rootCount; ++index) { | |
| 57 roots[index] = 1 - roots[index]; | |
| 58 } | |
| 59 } | |
| 60 return rootCount; | |
| 61 } | |
| 62 | |
| 63 static int addValidRoots(const double roots[4], const int count, double valid[4]
) { | |
| 64 int result = 0; | |
| 65 int index; | |
| 66 for (index = 0; index < count; ++index) { | |
| 67 if (!approximately_zero_or_more(roots[index]) || !approximately_one_or_l
ess(roots[index])) { | |
| 68 continue; | |
| 69 } | |
| 70 double t = 1 - roots[index]; | |
| 71 if (approximately_less_than_zero(t)) { | |
| 72 t = 0; | |
| 73 } else if (approximately_greater_than_one(t)) { | |
| 74 t = 1; | |
| 75 } | |
| 76 SkASSERT(t >= 0 && t <= 1); | |
| 77 valid[result++] = t; | |
| 78 } | |
| 79 return result; | |
| 80 } | |
| 81 | |
| 82 static bool only_end_pts_in_common(const SkDQuad& q1, const SkDQuad& q2) { | |
| 83 // the idea here is to see at minimum do a quick reject by rotating all points | |
| 84 // to either side of the line formed by connecting the endpoints | |
| 85 // if the opposite curves points are on the line or on the other side, the | |
| 86 // curves at most intersect at the endpoints | |
| 87 for (int oddMan = 0; oddMan < 3; ++oddMan) { | |
| 88 const SkDPoint* endPt[2]; | |
| 89 for (int opp = 1; opp < 3; ++opp) { | |
| 90 int end = oddMan ^ opp; // choose a value not equal to oddMan | |
| 91 if (3 == end) { // and correct so that largest value is 1 or 2 | |
| 92 end = opp; | |
| 93 } | |
| 94 endPt[opp - 1] = &q1[end]; | |
| 95 } | |
| 96 double origX = endPt[0]->fX; | |
| 97 double origY = endPt[0]->fY; | |
| 98 double adj = endPt[1]->fX - origX; | |
| 99 double opp = endPt[1]->fY - origY; | |
| 100 double sign = (q1[oddMan].fY - origY) * adj - (q1[oddMan].fX - origX) *
opp; | |
| 101 if (approximately_zero(sign)) { | |
| 102 goto tryNextHalfPlane; | |
| 103 } | |
| 104 for (int n = 0; n < 3; ++n) { | |
| 105 double test = (q2[n].fY - origY) * adj - (q2[n].fX - origX) * opp; | |
| 106 if (test * sign > 0 && !precisely_zero(test)) { | |
| 107 goto tryNextHalfPlane; | |
| 108 } | |
| 109 } | |
| 110 return true; | |
| 111 tryNextHalfPlane: | |
| 112 ; | |
| 113 } | |
| 114 return false; | |
| 115 } | |
| 116 | |
| 117 // returns false if there's more than one intercept or the intercept doesn't mat
ch the point | |
| 118 // returns true if the intercept was successfully added or if the | |
| 119 // original quads need to be subdivided | |
| 120 static bool add_intercept(const SkDQuad& q1, const SkDQuad& q2, double tMin, dou
ble tMax, | |
| 121 SkIntersections* i, bool* subDivide) { | |
| 122 double tMid = (tMin + tMax) / 2; | |
| 123 SkDPoint mid = q2.ptAtT(tMid); | |
| 124 SkDLine line; | |
| 125 line[0] = line[1] = mid; | |
| 126 SkDVector dxdy = q2.dxdyAtT(tMid); | |
| 127 line[0] -= dxdy; | |
| 128 line[1] += dxdy; | |
| 129 SkIntersections rootTs; | |
| 130 rootTs.allowNear(false); | |
| 131 int roots = rootTs.intersect(q1, line); | |
| 132 if (roots == 0) { | |
| 133 if (subDivide) { | |
| 134 *subDivide = true; | |
| 135 } | |
| 136 return true; | |
| 137 } | |
| 138 if (roots == 2) { | |
| 139 return false; | |
| 140 } | |
| 141 SkDPoint pt2 = q1.ptAtT(rootTs[0][0]); | |
| 142 if (!pt2.approximatelyEqual(mid)) { | |
| 143 return false; | |
| 144 } | |
| 145 i->insertSwap(rootTs[0][0], tMid, pt2); | |
| 146 return true; | |
| 147 } | |
| 148 | |
| 149 static bool is_linear_inner(const SkDQuad& q1, double t1s, double t1e, const SkD
Quad& q2, | |
| 150 double t2s, double t2e, SkIntersections* i, bool* su
bDivide) { | |
| 151 SkDQuad hull = q1.subDivide(t1s, t1e); | |
| 152 SkDLine line = {{hull[2], hull[0]}}; | |
| 153 const SkDLine* testLines[] = { &line, (const SkDLine*) &hull[0], (const SkDL
ine*) &hull[1] }; | |
| 154 const size_t kTestCount = SK_ARRAY_COUNT(testLines); | |
| 155 SkSTArray<kTestCount * 2, double, true> tsFound; | |
| 156 for (size_t index = 0; index < kTestCount; ++index) { | |
| 157 SkIntersections rootTs; | |
| 158 rootTs.allowNear(false); | |
| 159 int roots = rootTs.intersect(q2, *testLines[index]); | |
| 160 for (int idx2 = 0; idx2 < roots; ++idx2) { | |
| 161 double t = rootTs[0][idx2]; | |
| 162 #if 0 // def SK_DEBUG // FIXME : accurate for error = 16, error of 17.5 seen | |
| 163 // {{{136.08723965397621, 1648.2814535211637}, {593.49031197259478, 1190.8784277
439891}, {593.49031197259478, 544.0128173828125}}} | |
| 164 // {{{-968.181396484375, 544.0128173828125}, {592.2825927734375, 870.55249023437
5}, {593.435302734375, 557.8828125}}} | |
| 165 | |
| 166 SkDPoint qPt = q2.ptAtT(t); | |
| 167 SkDPoint lPt = testLines[index]->ptAtT(rootTs[1][idx2]); | |
| 168 SkASSERT(qPt.approximatelyDEqual(lPt)); | |
| 169 #endif | |
| 170 if (approximately_negative(t - t2s) || approximately_positive(t - t2
e)) { | |
| 171 continue; | |
| 172 } | |
| 173 tsFound.push_back(rootTs[0][idx2]); | |
| 174 } | |
| 175 } | |
| 176 int tCount = tsFound.count(); | |
| 177 if (tCount <= 0) { | |
| 178 return true; | |
| 179 } | |
| 180 double tMin, tMax; | |
| 181 if (tCount == 1) { | |
| 182 tMin = tMax = tsFound[0]; | |
| 183 } else { | |
| 184 SkASSERT(tCount > 1); | |
| 185 SkTQSort<double>(tsFound.begin(), tsFound.end() - 1); | |
| 186 tMin = tsFound[0]; | |
| 187 tMax = tsFound[tsFound.count() - 1]; | |
| 188 } | |
| 189 SkDPoint end = q2.ptAtT(t2s); | |
| 190 bool startInTriangle = hull.pointInHull(end); | |
| 191 if (startInTriangle) { | |
| 192 tMin = t2s; | |
| 193 } | |
| 194 end = q2.ptAtT(t2e); | |
| 195 bool endInTriangle = hull.pointInHull(end); | |
| 196 if (endInTriangle) { | |
| 197 tMax = t2e; | |
| 198 } | |
| 199 int split = 0; | |
| 200 SkDVector dxy1, dxy2; | |
| 201 if (tMin != tMax || tCount > 2) { | |
| 202 dxy2 = q2.dxdyAtT(tMin); | |
| 203 for (int index = 1; index < tCount; ++index) { | |
| 204 dxy1 = dxy2; | |
| 205 dxy2 = q2.dxdyAtT(tsFound[index]); | |
| 206 double dot = dxy1.dot(dxy2); | |
| 207 if (dot < 0) { | |
| 208 split = index - 1; | |
| 209 break; | |
| 210 } | |
| 211 } | |
| 212 } | |
| 213 if (split == 0) { // there's one point | |
| 214 if (add_intercept(q1, q2, tMin, tMax, i, subDivide)) { | |
| 215 return true; | |
| 216 } | |
| 217 i->swap(); | |
| 218 return is_linear_inner(q2, tMin, tMax, q1, t1s, t1e, i, subDivide); | |
| 219 } | |
| 220 // At this point, we have two ranges of t values -- treat each separately at
the split | |
| 221 bool result; | |
| 222 if (add_intercept(q1, q2, tMin, tsFound[split - 1], i, subDivide)) { | |
| 223 result = true; | |
| 224 } else { | |
| 225 i->swap(); | |
| 226 result = is_linear_inner(q2, tMin, tsFound[split - 1], q1, t1s, t1e, i,
subDivide); | |
| 227 } | |
| 228 if (add_intercept(q1, q2, tsFound[split], tMax, i, subDivide)) { | |
| 229 result = true; | |
| 230 } else { | |
| 231 i->swap(); | |
| 232 result |= is_linear_inner(q2, tsFound[split], tMax, q1, t1s, t1e, i, sub
Divide); | |
| 233 } | |
| 234 return result; | |
| 235 } | |
| 236 | |
| 237 static double flat_measure(const SkDQuad& q) { | |
| 238 SkDVector mid = q[1] - q[0]; | |
| 239 SkDVector dxy = q[2] - q[0]; | |
| 240 double length = dxy.length(); // OPTIMIZE: get rid of sqrt | |
| 241 return fabs(mid.cross(dxy) / length); | |
| 242 } | |
| 243 | |
| 244 // FIXME ? should this measure both and then use the quad that is the flattest a
s the line? | |
| 245 static bool is_linear(const SkDQuad& q1, const SkDQuad& q2, SkIntersections* i)
{ | |
| 246 if (i->flatMeasure()) { | |
| 247 // for backward compatibility, use the old method when called from cubic
s | |
| 248 // FIXME: figure out how to fix cubics when it calls the new path | |
| 249 double measure = flat_measure(q1); | |
| 250 // OPTIMIZE: (get rid of sqrt) use approximately_zero | |
| 251 if (!approximately_zero_sqrt(measure)) { // approximately_zero_sqrt | |
| 252 return false; | |
| 253 } | |
| 254 } else { | |
| 255 if (!q1.isLinear(0, 2)) { | |
| 256 return false; | |
| 257 } | |
| 258 } | |
| 259 return is_linear_inner(q1, 0, 1, q2, 0, 1, i, NULL); | |
| 260 } | |
| 261 | |
| 262 // FIXME: if flat measure is sufficiently large, then probably the quartic solut
ion failed | |
| 263 // avoid imprecision incurred with chopAt | |
| 264 static void relaxed_is_linear(const SkDQuad* q1, double s1, double e1, const SkD
Quad* q2, | |
| 265 double s2, double e2, SkIntersections* i) { | |
| 266 double m1 = flat_measure(*q1); | |
| 267 double m2 = flat_measure(*q2); | |
| 268 i->reset(); | |
| 269 const SkDQuad* rounder, *flatter; | |
| 270 double sf, midf, ef, sr, er; | |
| 271 if (m2 < m1) { | |
| 272 rounder = q1; | |
| 273 sr = s1; | |
| 274 er = e1; | |
| 275 flatter = q2; | |
| 276 sf = s2; | |
| 277 midf = (s2 + e2) / 2; | |
| 278 ef = e2; | |
| 279 } else { | |
| 280 rounder = q2; | |
| 281 sr = s2; | |
| 282 er = e2; | |
| 283 flatter = q1; | |
| 284 sf = s1; | |
| 285 midf = (s1 + e1) / 2; | |
| 286 ef = e1; | |
| 287 } | |
| 288 bool subDivide = false; | |
| 289 is_linear_inner(*flatter, sf, ef, *rounder, sr, er, i, &subDivide); | |
| 290 if (subDivide) { | |
| 291 relaxed_is_linear(flatter, sf, midf, rounder, sr, er, i); | |
| 292 relaxed_is_linear(flatter, midf, ef, rounder, sr, er, i); | |
| 293 } | |
| 294 if (m2 < m1) { | |
| 295 i->swapPts(); | |
| 296 } | |
| 297 } | |
| 298 | |
| 299 // each time through the loop, this computes values it had from the last loop | |
| 300 // if i == j == 1, the center values are still good | |
| 301 // otherwise, for i != 1 or j != 1, four of the values are still good | |
| 302 // and if i == 1 ^ j == 1, an additional value is good | |
| 303 static bool binary_search(const SkDQuad& quad1, const SkDQuad& quad2, double* t1
Seed, | |
| 304 double* t2Seed, SkDPoint* pt) { | |
| 305 double tStep = ROUGH_EPSILON; | |
| 306 SkDPoint t1[3], t2[3]; | |
| 307 int calcMask = ~0; | |
| 308 do { | |
| 309 if (calcMask & (1 << 1)) t1[1] = quad1.ptAtT(*t1Seed); | |
| 310 if (calcMask & (1 << 4)) t2[1] = quad2.ptAtT(*t2Seed); | |
| 311 if (t1[1].approximatelyEqual(t2[1])) { | |
| 312 *pt = t1[1]; | |
| 313 #if ONE_OFF_DEBUG | |
| 314 SkDebugf("%s t1=%1.9g t2=%1.9g (%1.9g,%1.9g) == (%1.9g,%1.9g)\n", __
FUNCTION__, | |
| 315 t1Seed, t2Seed, t1[1].fX, t1[1].fY, t2[1].fX, t2[1].fY); | |
| 316 #endif | |
| 317 if (*t1Seed < 0) { | |
| 318 *t1Seed = 0; | |
| 319 } else if (*t1Seed > 1) { | |
| 320 *t1Seed = 1; | |
| 321 } | |
| 322 if (*t2Seed < 0) { | |
| 323 *t2Seed = 0; | |
| 324 } else if (*t2Seed > 1) { | |
| 325 *t2Seed = 1; | |
| 326 } | |
| 327 return true; | |
| 328 } | |
| 329 if (calcMask & (1 << 0)) t1[0] = quad1.ptAtT(SkTMax(0., *t1Seed - tStep)
); | |
| 330 if (calcMask & (1 << 2)) t1[2] = quad1.ptAtT(SkTMin(1., *t1Seed + tStep)
); | |
| 331 if (calcMask & (1 << 3)) t2[0] = quad2.ptAtT(SkTMax(0., *t2Seed - tStep)
); | |
| 332 if (calcMask & (1 << 5)) t2[2] = quad2.ptAtT(SkTMin(1., *t2Seed + tStep)
); | |
| 333 double dist[3][3]; | |
| 334 // OPTIMIZE: using calcMask value permits skipping some distance calcuat
ions | |
| 335 // if prior loop's results are moved to correct slot for reuse | |
| 336 dist[1][1] = t1[1].distanceSquared(t2[1]); | |
| 337 int best_i = 1, best_j = 1; | |
| 338 for (int i = 0; i < 3; ++i) { | |
| 339 for (int j = 0; j < 3; ++j) { | |
| 340 if (i == 1 && j == 1) { | |
| 341 continue; | |
| 342 } | |
| 343 dist[i][j] = t1[i].distanceSquared(t2[j]); | |
| 344 if (dist[best_i][best_j] > dist[i][j]) { | |
| 345 best_i = i; | |
| 346 best_j = j; | |
| 347 } | |
| 348 } | |
| 349 } | |
| 350 if (best_i == 1 && best_j == 1) { | |
| 351 tStep /= 2; | |
| 352 if (tStep < FLT_EPSILON_HALF) { | |
| 353 break; | |
| 354 } | |
| 355 calcMask = (1 << 0) | (1 << 2) | (1 << 3) | (1 << 5); | |
| 356 continue; | |
| 357 } | |
| 358 if (best_i == 0) { | |
| 359 *t1Seed -= tStep; | |
| 360 t1[2] = t1[1]; | |
| 361 t1[1] = t1[0]; | |
| 362 calcMask = 1 << 0; | |
| 363 } else if (best_i == 2) { | |
| 364 *t1Seed += tStep; | |
| 365 t1[0] = t1[1]; | |
| 366 t1[1] = t1[2]; | |
| 367 calcMask = 1 << 2; | |
| 368 } else { | |
| 369 calcMask = 0; | |
| 370 } | |
| 371 if (best_j == 0) { | |
| 372 *t2Seed -= tStep; | |
| 373 t2[2] = t2[1]; | |
| 374 t2[1] = t2[0]; | |
| 375 calcMask |= 1 << 3; | |
| 376 } else if (best_j == 2) { | |
| 377 *t2Seed += tStep; | |
| 378 t2[0] = t2[1]; | |
| 379 t2[1] = t2[2]; | |
| 380 calcMask |= 1 << 5; | |
| 381 } | |
| 382 } while (true); | |
| 383 #if ONE_OFF_DEBUG | |
| 384 SkDebugf("%s t1=%1.9g t2=%1.9g (%1.9g,%1.9g) != (%1.9g,%1.9g) %s\n", __FUNCT
ION__, | |
| 385 t1Seed, t2Seed, t1[1].fX, t1[1].fY, t1[2].fX, t1[2].fY); | |
| 386 #endif | |
| 387 return false; | |
| 388 } | |
| 389 | |
| 390 static void lookNearEnd(const SkDQuad& q1, const SkDQuad& q2, int testT, | |
| 391 const SkIntersections& orig, bool swap, SkIntersections* i) { | |
| 392 if (orig.used() == 1 && orig[!swap][0] == testT) { | |
| 393 return; | |
| 394 } | |
| 395 if (orig.used() == 2 && orig[!swap][1] == testT) { | |
| 396 return; | |
| 397 } | |
| 398 SkDLine tmpLine; | |
| 399 int testTIndex = testT << 1; | |
| 400 tmpLine[0] = tmpLine[1] = q2[testTIndex]; | |
| 401 tmpLine[1].fX += q2[1].fY - q2[testTIndex].fY; | |
| 402 tmpLine[1].fY -= q2[1].fX - q2[testTIndex].fX; | |
| 403 SkIntersections impTs; | |
| 404 impTs.intersectRay(q1, tmpLine); | |
| 405 for (int index = 0; index < impTs.used(); ++index) { | |
| 406 SkDPoint realPt = impTs.pt(index); | |
| 407 if (!tmpLine[0].approximatelyPEqual(realPt)) { | |
| 408 continue; | |
| 409 } | |
| 410 if (swap) { | |
| 411 i->insert(testT, impTs[0][index], tmpLine[0]); | |
| 412 } else { | |
| 413 i->insert(impTs[0][index], testT, tmpLine[0]); | |
| 414 } | |
| 415 } | |
| 416 } | |
| 417 | |
| 418 int SkIntersections::intersect(const SkDQuad& q1, const SkDQuad& q2) { | |
| 419 fMax = 4; | |
| 420 bool exactMatch = false; | |
| 421 // if the quads share an end point, check to see if they overlap | |
| 422 for (int i1 = 0; i1 < 3; i1 += 2) { | |
| 423 for (int i2 = 0; i2 < 3; i2 += 2) { | |
| 424 if (q1[i1].asSkPoint() == q2[i2].asSkPoint()) { | |
| 425 insert(i1 >> 1, i2 >> 1, q1[i1]); | |
| 426 exactMatch = true; | |
| 427 } | |
| 428 } | |
| 429 } | |
| 430 SkASSERT(fUsed < 3); | |
| 431 if (only_end_pts_in_common(q1, q2)) { | |
| 432 return fUsed; | |
| 433 } | |
| 434 if (only_end_pts_in_common(q2, q1)) { | |
| 435 return fUsed; | |
| 436 } | |
| 437 // see if either quad is really a line | |
| 438 // FIXME: figure out why reduce step didn't find this earlier | |
| 439 if (is_linear(q1, q2, this)) { | |
| 440 return fUsed; | |
| 441 } | |
| 442 SkIntersections swapped; | |
| 443 swapped.setMax(fMax); | |
| 444 if (is_linear(q2, q1, &swapped)) { | |
| 445 swapped.swapPts(); | |
| 446 *this = swapped; | |
| 447 return fUsed; | |
| 448 } | |
| 449 SkIntersections copyI(*this); | |
| 450 lookNearEnd(q1, q2, 0, *this, false, ©I); | |
| 451 lookNearEnd(q1, q2, 1, *this, false, ©I); | |
| 452 lookNearEnd(q2, q1, 0, *this, true, ©I); | |
| 453 lookNearEnd(q2, q1, 1, *this, true, ©I); | |
| 454 int innerEqual = 0; | |
| 455 if (copyI.fUsed >= 2) { | |
| 456 SkASSERT(copyI.fUsed <= 4); | |
| 457 double width = copyI[0][1] - copyI[0][0]; | |
| 458 int midEnd = 1; | |
| 459 for (int index = 2; index < copyI.fUsed; ++index) { | |
| 460 double testWidth = copyI[0][index] - copyI[0][index - 1]; | |
| 461 if (testWidth <= width) { | |
| 462 continue; | |
| 463 } | |
| 464 midEnd = index; | |
| 465 } | |
| 466 for (int index = 0; index < 2; ++index) { | |
| 467 double testT = (copyI[0][midEnd] * (index + 1) | |
| 468 + copyI[0][midEnd - 1] * (2 - index)) / 3; | |
| 469 SkDPoint testPt1 = q1.ptAtT(testT); | |
| 470 testT = (copyI[1][midEnd] * (index + 1) + copyI[1][midEnd - 1] * (2
- index)) / 3; | |
| 471 SkDPoint testPt2 = q2.ptAtT(testT); | |
| 472 innerEqual += testPt1.approximatelyEqual(testPt2); | |
| 473 } | |
| 474 } | |
| 475 bool expectCoincident = copyI.fUsed >= 2 && innerEqual == 2; | |
| 476 if (expectCoincident) { | |
| 477 reset(); | |
| 478 insertCoincident(copyI[0][0], copyI[1][0], copyI.fPt[0]); | |
| 479 int last = copyI.fUsed - 1; | |
| 480 insertCoincident(copyI[0][last], copyI[1][last], copyI.fPt[last]); | |
| 481 return fUsed; | |
| 482 } | |
| 483 SkDQuadImplicit i1(q1); | |
| 484 SkDQuadImplicit i2(q2); | |
| 485 int index; | |
| 486 bool flip1 = q1[2] == q2[0]; | |
| 487 bool flip2 = q1[0] == q2[2]; | |
| 488 bool useCubic = q1[0] == q2[0]; | |
| 489 double roots1[4]; | |
| 490 int rootCount = findRoots(i2, q1, roots1, useCubic, flip1, 0); | |
| 491 // OPTIMIZATION: could short circuit here if all roots are < 0 or > 1 | |
| 492 double roots1Copy[4]; | |
| 493 SkDEBUGCODE(sk_bzero(roots1Copy, sizeof(roots1Copy))); | |
| 494 int r1Count = addValidRoots(roots1, rootCount, roots1Copy); | |
| 495 SkDPoint pts1[4]; | |
| 496 for (index = 0; index < r1Count; ++index) { | |
| 497 pts1[index] = q1.ptAtT(roots1Copy[index]); | |
| 498 } | |
| 499 double roots2[4]; | |
| 500 int rootCount2 = findRoots(i1, q2, roots2, useCubic, flip2, 0); | |
| 501 double roots2Copy[4]; | |
| 502 int r2Count = addValidRoots(roots2, rootCount2, roots2Copy); | |
| 503 SkDPoint pts2[4]; | |
| 504 for (index = 0; index < r2Count; ++index) { | |
| 505 pts2[index] = q2.ptAtT(roots2Copy[index]); | |
| 506 } | |
| 507 bool triedBinary = false; | |
| 508 if (r1Count == r2Count && r1Count <= 1) { | |
| 509 if (r1Count == 1 && used() == 0) { | |
| 510 if (pts1[0].approximatelyEqual(pts2[0])) { | |
| 511 insert(roots1Copy[0], roots2Copy[0], pts1[0]); | |
| 512 } else { | |
| 513 // find intersection by chasing t | |
| 514 triedBinary = true; | |
| 515 if (binary_search(q1, q2, roots1Copy, roots2Copy, pts1)) { | |
| 516 insert(roots1Copy[0], roots2Copy[0], pts1[0]); | |
| 517 } | |
| 518 } | |
| 519 } | |
| 520 return fUsed; | |
| 521 } | |
| 522 int closest[4]; | |
| 523 double dist[4]; | |
| 524 bool foundSomething = false; | |
| 525 for (index = 0; index < r1Count; ++index) { | |
| 526 dist[index] = DBL_MAX; | |
| 527 closest[index] = -1; | |
| 528 for (int ndex2 = 0; ndex2 < r2Count; ++ndex2) { | |
| 529 if (!pts2[ndex2].approximatelyEqual(pts1[index])) { | |
| 530 continue; | |
| 531 } | |
| 532 double dx = pts2[ndex2].fX - pts1[index].fX; | |
| 533 double dy = pts2[ndex2].fY - pts1[index].fY; | |
| 534 double distance = dx * dx + dy * dy; | |
| 535 if (dist[index] <= distance) { | |
| 536 continue; | |
| 537 } | |
| 538 for (int outer = 0; outer < index; ++outer) { | |
| 539 if (closest[outer] != ndex2) { | |
| 540 continue; | |
| 541 } | |
| 542 if (dist[outer] < distance) { | |
| 543 goto next; | |
| 544 } | |
| 545 closest[outer] = -1; | |
| 546 } | |
| 547 dist[index] = distance; | |
| 548 closest[index] = ndex2; | |
| 549 foundSomething = true; | |
| 550 next: | |
| 551 ; | |
| 552 } | |
| 553 } | |
| 554 if (r1Count && r2Count && !foundSomething) { | |
| 555 if (exactMatch) { | |
| 556 SkASSERT(fUsed > 0); | |
| 557 return fUsed; | |
| 558 } | |
| 559 relaxed_is_linear(&q1, 0, 1, &q2, 0, 1, this); | |
| 560 if (fUsed) { | |
| 561 return fUsed; | |
| 562 } | |
| 563 // maybe the curves are nearly coincident | |
| 564 if (!triedBinary && binary_search(q1, q2, roots1Copy, roots2Copy, pts1))
{ | |
| 565 insert(roots1Copy[0], roots2Copy[0], pts1[0]); | |
| 566 } | |
| 567 return fUsed; | |
| 568 } | |
| 569 int used = 0; | |
| 570 do { | |
| 571 double lowest = DBL_MAX; | |
| 572 int lowestIndex = -1; | |
| 573 for (index = 0; index < r1Count; ++index) { | |
| 574 if (closest[index] < 0) { | |
| 575 continue; | |
| 576 } | |
| 577 if (roots1Copy[index] < lowest) { | |
| 578 lowestIndex = index; | |
| 579 lowest = roots1Copy[index]; | |
| 580 } | |
| 581 } | |
| 582 if (lowestIndex < 0) { | |
| 583 break; | |
| 584 } | |
| 585 insert(roots1Copy[lowestIndex], roots2Copy[closest[lowestIndex]], | |
| 586 pts1[lowestIndex]); | |
| 587 closest[lowestIndex] = -1; | |
| 588 } while (++used < r1Count); | |
| 589 return fUsed; | |
| 590 } | |
| 591 | |
| 592 void SkIntersections::alignQuadPts(const SkPoint q1[3], const SkPoint q2[3]) { | |
| 593 for (int index = 0; index < used(); ++index) { | |
| 594 const SkPoint result = pt(index).asSkPoint(); | |
| 595 if (q1[0] == result || q1[2] == result || q2[0] == result || q2[2] == re
sult) { | |
| 596 continue; | |
| 597 } | |
| 598 if (SkDPoint::ApproximatelyEqual(q1[0], result)) { | |
| 599 fPt[index].set(q1[0]); | |
| 600 // SkASSERT(way_roughly_zero(fT[0][index])); // this value can be bi
gger than way rough | |
| 601 fT[0][index] = 0; | |
| 602 } else if (SkDPoint::ApproximatelyEqual(q1[2], result)) { | |
| 603 fPt[index].set(q1[2]); | |
| 604 // SkASSERT(way_roughly_equal(fT[0][index], 1)); | |
| 605 fT[0][index] = 1; | |
| 606 } | |
| 607 if (SkDPoint::ApproximatelyEqual(q2[0], result)) { | |
| 608 fPt[index].set(q2[0]); | |
| 609 // SkASSERT(way_roughly_zero(fT[1][index])); | |
| 610 fT[1][index] = 0; | |
| 611 } else if (SkDPoint::ApproximatelyEqual(q2[2], result)) { | |
| 612 fPt[index].set(q2[2]); | |
| 613 // SkASSERT(way_roughly_equal(fT[1][index], 1)); | |
| 614 fT[1][index] = 1; | |
| 615 } | |
| 616 } | |
| 617 } | |
| OLD | NEW |