epoger@google.com | ec3ed6a | 2011-07-28 14:26:00 +0000 | [diff] [blame] | 1 | |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 2 | /* |
epoger@google.com | ec3ed6a | 2011-07-28 14:26:00 +0000 | [diff] [blame] | 3 | * Copyright 2008 The Android Open Source Project |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 4 | * |
epoger@google.com | ec3ed6a | 2011-07-28 14:26:00 +0000 | [diff] [blame] | 5 | * Use of this source code is governed by a BSD-style license that can be |
| 6 | * found in the LICENSE file. |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 7 | */ |
| 8 | |
epoger@google.com | ec3ed6a | 2011-07-28 14:26:00 +0000 | [diff] [blame] | 9 | |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 10 | #include "SkPathMeasure.h" |
| 11 | #include "SkGeometry.h" |
| 12 | #include "SkPath.h" |
| 13 | #include "SkTSearch.h" |
| 14 | |
| 15 | // these must be 0,1,2 since they are in our 2-bit field |
| 16 | enum { |
| 17 | kLine_SegType, |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 18 | kQuad_SegType, |
| 19 | kCubic_SegType |
| 20 | }; |
| 21 | |
| 22 | #define kMaxTValue 32767 |
| 23 | |
| 24 | static inline SkScalar tValue2Scalar(int t) { |
| 25 | SkASSERT((unsigned)t <= kMaxTValue); |
| 26 | |
| 27 | #ifdef SK_SCALAR_IS_FLOAT |
| 28 | return t * 3.05185e-5f; // t / 32767 |
| 29 | #else |
| 30 | return (t + (t >> 14)) << 1; |
| 31 | #endif |
| 32 | } |
| 33 | |
| 34 | SkScalar SkPathMeasure::Segment::getScalarT() const { |
| 35 | return tValue2Scalar(fTValue); |
| 36 | } |
| 37 | |
| 38 | const SkPathMeasure::Segment* SkPathMeasure::NextSegment(const Segment* seg) { |
| 39 | unsigned ptIndex = seg->fPtIndex; |
| 40 | |
| 41 | do { |
| 42 | ++seg; |
| 43 | } while (seg->fPtIndex == ptIndex); |
| 44 | return seg; |
| 45 | } |
| 46 | |
| 47 | /////////////////////////////////////////////////////////////////////////////// |
| 48 | |
| 49 | static inline int tspan_big_enough(int tspan) { |
| 50 | SkASSERT((unsigned)tspan <= kMaxTValue); |
| 51 | return tspan >> 10; |
| 52 | } |
| 53 | |
| 54 | #if 0 |
| 55 | static inline bool tangents_too_curvy(const SkVector& tan0, SkVector& tan1) { |
| 56 | static const SkScalar kFlatEnoughTangentDotProd = SK_Scalar1 * 99 / 100; |
| 57 | |
| 58 | SkASSERT(kFlatEnoughTangentDotProd > 0 && |
| 59 | kFlatEnoughTangentDotProd < SK_Scalar1); |
| 60 | |
| 61 | return SkPoint::DotProduct(tan0, tan1) < kFlatEnoughTangentDotProd; |
| 62 | } |
| 63 | #endif |
| 64 | |
| 65 | // can't use tangents, since we need [0..1..................2] to be seen |
| 66 | // as definitely not a line (it is when drawn, but not parametrically) |
| 67 | // so we compare midpoints |
| 68 | #define CHEAP_DIST_LIMIT (SK_Scalar1/2) // just made this value up |
| 69 | |
| 70 | static bool quad_too_curvy(const SkPoint pts[3]) { |
| 71 | // diff = (a/4 + b/2 + c/4) - (a/2 + c/2) |
| 72 | // diff = -a/4 + b/2 - c/4 |
| 73 | SkScalar dx = SkScalarHalf(pts[1].fX) - |
| 74 | SkScalarHalf(SkScalarHalf(pts[0].fX + pts[2].fX)); |
| 75 | SkScalar dy = SkScalarHalf(pts[1].fY) - |
| 76 | SkScalarHalf(SkScalarHalf(pts[0].fY + pts[2].fY)); |
| 77 | |
| 78 | SkScalar dist = SkMaxScalar(SkScalarAbs(dx), SkScalarAbs(dy)); |
| 79 | return dist > CHEAP_DIST_LIMIT; |
| 80 | } |
| 81 | |
| 82 | static bool cheap_dist_exceeds_limit(const SkPoint& pt, |
| 83 | SkScalar x, SkScalar y) { |
| 84 | SkScalar dist = SkMaxScalar(SkScalarAbs(x - pt.fX), SkScalarAbs(y - pt.fY)); |
| 85 | // just made up the 1/2 |
| 86 | return dist > CHEAP_DIST_LIMIT; |
| 87 | } |
| 88 | |
| 89 | static bool cubic_too_curvy(const SkPoint pts[4]) { |
| 90 | return cheap_dist_exceeds_limit(pts[1], |
| 91 | SkScalarInterp(pts[0].fX, pts[3].fX, SK_Scalar1/3), |
| 92 | SkScalarInterp(pts[0].fY, pts[3].fY, SK_Scalar1/3)) |
| 93 | || |
| 94 | cheap_dist_exceeds_limit(pts[2], |
| 95 | SkScalarInterp(pts[0].fX, pts[3].fX, SK_Scalar1*2/3), |
| 96 | SkScalarInterp(pts[0].fY, pts[3].fY, SK_Scalar1*2/3)); |
| 97 | } |
| 98 | |
| 99 | SkScalar SkPathMeasure::compute_quad_segs(const SkPoint pts[3], |
| 100 | SkScalar distance, int mint, int maxt, int ptIndex) { |
| 101 | if (tspan_big_enough(maxt - mint) && quad_too_curvy(pts)) { |
| 102 | SkPoint tmp[5]; |
| 103 | int halft = (mint + maxt) >> 1; |
| 104 | |
| 105 | SkChopQuadAtHalf(pts, tmp); |
| 106 | distance = this->compute_quad_segs(tmp, distance, mint, halft, ptIndex); |
| 107 | distance = this->compute_quad_segs(&tmp[2], distance, halft, maxt, ptIndex); |
| 108 | } else { |
| 109 | SkScalar d = SkPoint::Distance(pts[0], pts[2]); |
| 110 | SkASSERT(d >= 0); |
reed@google.com | ded4414 | 2012-04-27 20:22:07 +0000 | [diff] [blame^] | 111 | if (SkScalarNearlyZero(d)) { |
| 112 | d = 0; |
| 113 | } |
| 114 | SkScalar prevD = distance; |
| 115 | distance += d; |
| 116 | if (distance > prevD) { |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 117 | Segment* seg = fSegments.append(); |
| 118 | seg->fDistance = distance; |
| 119 | seg->fPtIndex = ptIndex; |
| 120 | seg->fType = kQuad_SegType; |
| 121 | seg->fTValue = maxt; |
| 122 | } |
| 123 | } |
| 124 | return distance; |
| 125 | } |
| 126 | |
| 127 | SkScalar SkPathMeasure::compute_cubic_segs(const SkPoint pts[4], |
| 128 | SkScalar distance, int mint, int maxt, int ptIndex) { |
| 129 | if (tspan_big_enough(maxt - mint) && cubic_too_curvy(pts)) { |
| 130 | SkPoint tmp[7]; |
| 131 | int halft = (mint + maxt) >> 1; |
| 132 | |
| 133 | SkChopCubicAtHalf(pts, tmp); |
| 134 | distance = this->compute_cubic_segs(tmp, distance, mint, halft, ptIndex); |
| 135 | distance = this->compute_cubic_segs(&tmp[3], distance, halft, maxt, ptIndex); |
| 136 | } else { |
| 137 | SkScalar d = SkPoint::Distance(pts[0], pts[3]); |
| 138 | SkASSERT(d >= 0); |
reed@google.com | ded4414 | 2012-04-27 20:22:07 +0000 | [diff] [blame^] | 139 | if (SkScalarNearlyZero(d)) { |
| 140 | d = 0; |
| 141 | } |
| 142 | SkScalar prevD = distance; |
| 143 | distance += d; |
| 144 | if (distance > prevD) { |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 145 | Segment* seg = fSegments.append(); |
| 146 | seg->fDistance = distance; |
| 147 | seg->fPtIndex = ptIndex; |
| 148 | seg->fType = kCubic_SegType; |
| 149 | seg->fTValue = maxt; |
| 150 | } |
| 151 | } |
| 152 | return distance; |
| 153 | } |
| 154 | |
| 155 | void SkPathMeasure::buildSegments() { |
| 156 | SkPoint pts[4]; |
| 157 | int ptIndex = fFirstPtIndex; |
reed@google.com | fab1ddd | 2012-04-20 15:10:32 +0000 | [diff] [blame] | 158 | SkScalar distance = 0; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 159 | bool isClosed = fForceClosed; |
| 160 | bool firstMoveTo = ptIndex < 0; |
| 161 | Segment* seg; |
| 162 | |
reed@google.com | fab1ddd | 2012-04-20 15:10:32 +0000 | [diff] [blame] | 163 | /* Note: |
| 164 | * as we accumulate distance, we have to check that the result of += |
| 165 | * actually made it larger, since a very small delta might be > 0, but |
| 166 | * still have no effect on distance (if distance >>> delta). |
reed@google.com | ded4414 | 2012-04-27 20:22:07 +0000 | [diff] [blame^] | 167 | * |
| 168 | * We do this check below, and in compute_quad_segs and compute_cubic_segs |
reed@google.com | fab1ddd | 2012-04-20 15:10:32 +0000 | [diff] [blame] | 169 | */ |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 170 | fSegments.reset(); |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 171 | bool done = false; |
| 172 | do { |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 173 | switch (fIter.next(pts)) { |
| 174 | case SkPath::kMove_Verb: |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 175 | ptIndex += 1; |
| 176 | fPts.append(1, pts); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 177 | if (!firstMoveTo) { |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 178 | done = true; |
| 179 | break; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 180 | } |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 181 | firstMoveTo = false; |
| 182 | break; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 183 | |
reed@google.com | fab1ddd | 2012-04-20 15:10:32 +0000 | [diff] [blame] | 184 | case SkPath::kLine_Verb: { |
| 185 | SkScalar d = SkPoint::Distance(pts[0], pts[1]); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 186 | SkASSERT(d >= 0); |
reed@google.com | fab1ddd | 2012-04-20 15:10:32 +0000 | [diff] [blame] | 187 | SkScalar prevD = distance; |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 188 | distance += d; |
reed@google.com | fab1ddd | 2012-04-20 15:10:32 +0000 | [diff] [blame] | 189 | if (distance > prevD) { |
| 190 | seg = fSegments.append(); |
| 191 | seg->fDistance = distance; |
| 192 | seg->fPtIndex = ptIndex; |
| 193 | seg->fType = kLine_SegType; |
| 194 | seg->fTValue = kMaxTValue; |
| 195 | fPts.append(1, pts + 1); |
| 196 | ptIndex++; |
| 197 | } |
| 198 | } break; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 199 | |
reed@google.com | fab1ddd | 2012-04-20 15:10:32 +0000 | [diff] [blame] | 200 | case SkPath::kQuad_Verb: { |
| 201 | SkScalar prevD = distance; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 202 | distance = this->compute_quad_segs(pts, distance, 0, |
| 203 | kMaxTValue, ptIndex); |
reed@google.com | fab1ddd | 2012-04-20 15:10:32 +0000 | [diff] [blame] | 204 | if (distance > prevD) { |
| 205 | fPts.append(2, pts + 1); |
| 206 | ptIndex += 2; |
| 207 | } |
| 208 | } break; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 209 | |
reed@google.com | fab1ddd | 2012-04-20 15:10:32 +0000 | [diff] [blame] | 210 | case SkPath::kCubic_Verb: { |
| 211 | SkScalar prevD = distance; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 212 | distance = this->compute_cubic_segs(pts, distance, 0, |
| 213 | kMaxTValue, ptIndex); |
reed@google.com | fab1ddd | 2012-04-20 15:10:32 +0000 | [diff] [blame] | 214 | if (distance > prevD) { |
| 215 | fPts.append(3, pts + 1); |
| 216 | ptIndex += 3; |
| 217 | } |
| 218 | } break; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 219 | |
| 220 | case SkPath::kClose_Verb: |
| 221 | isClosed = true; |
| 222 | break; |
| 223 | |
| 224 | case SkPath::kDone_Verb: |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 225 | done = true; |
| 226 | break; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 227 | } |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 228 | } while (!done); |
| 229 | |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 230 | fLength = distance; |
| 231 | fIsClosed = isClosed; |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 232 | fFirstPtIndex = ptIndex; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 233 | |
| 234 | #ifdef SK_DEBUG |
| 235 | { |
| 236 | const Segment* seg = fSegments.begin(); |
| 237 | const Segment* stop = fSegments.end(); |
| 238 | unsigned ptIndex = 0; |
| 239 | SkScalar distance = 0; |
| 240 | |
| 241 | while (seg < stop) { |
| 242 | SkASSERT(seg->fDistance > distance); |
| 243 | SkASSERT(seg->fPtIndex >= ptIndex); |
| 244 | SkASSERT(seg->fTValue > 0); |
| 245 | |
| 246 | const Segment* s = seg; |
| 247 | while (s < stop - 1 && s[0].fPtIndex == s[1].fPtIndex) { |
| 248 | SkASSERT(s[0].fType == s[1].fType); |
| 249 | SkASSERT(s[0].fTValue < s[1].fTValue); |
| 250 | s += 1; |
| 251 | } |
| 252 | |
| 253 | distance = seg->fDistance; |
| 254 | ptIndex = seg->fPtIndex; |
| 255 | seg += 1; |
| 256 | } |
| 257 | // SkDebugf("\n"); |
| 258 | } |
| 259 | #endif |
| 260 | } |
| 261 | |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 262 | static void compute_pos_tan(const SkTDArray<SkPoint>& segmentPts, int ptIndex, |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 263 | int segType, SkScalar t, SkPoint* pos, SkVector* tangent) { |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 264 | const SkPoint* pts = &segmentPts[ptIndex]; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 265 | |
| 266 | switch (segType) { |
| 267 | case kLine_SegType: |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 268 | if (pos) { |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 269 | pos->set(SkScalarInterp(pts[0].fX, pts[1].fX, t), |
| 270 | SkScalarInterp(pts[0].fY, pts[1].fY, t)); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 271 | } |
| 272 | if (tangent) { |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 273 | tangent->setNormalize(pts[1].fX - pts[0].fX, pts[1].fY - pts[0].fY); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 274 | } |
| 275 | break; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 276 | case kQuad_SegType: |
| 277 | SkEvalQuadAt(pts, t, pos, tangent); |
| 278 | if (tangent) { |
| 279 | tangent->normalize(); |
| 280 | } |
| 281 | break; |
| 282 | case kCubic_SegType: |
| 283 | SkEvalCubicAt(pts, t, pos, tangent, NULL); |
| 284 | if (tangent) { |
| 285 | tangent->normalize(); |
| 286 | } |
| 287 | break; |
| 288 | default: |
tomhudson@google.com | 0c00f21 | 2011-12-28 14:59:50 +0000 | [diff] [blame] | 289 | SkDEBUGFAIL("unknown segType"); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 290 | } |
| 291 | } |
| 292 | |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 293 | static void seg_to(const SkTDArray<SkPoint>& segmentPts, int ptIndex, |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 294 | int segType, SkScalar startT, SkScalar stopT, SkPath* dst) { |
| 295 | SkASSERT(startT >= 0 && startT <= SK_Scalar1); |
| 296 | SkASSERT(stopT >= 0 && stopT <= SK_Scalar1); |
| 297 | SkASSERT(startT <= stopT); |
| 298 | |
| 299 | if (SkScalarNearlyZero(stopT - startT)) { |
| 300 | return; |
| 301 | } |
| 302 | |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 303 | const SkPoint* pts = &segmentPts[ptIndex]; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 304 | SkPoint tmp0[7], tmp1[7]; |
| 305 | |
| 306 | switch (segType) { |
| 307 | case kLine_SegType: |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 308 | if (stopT == kMaxTValue) { |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 309 | dst->lineTo(pts[1]); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 310 | } else { |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 311 | dst->lineTo(SkScalarInterp(pts[0].fX, pts[1].fX, stopT), |
| 312 | SkScalarInterp(pts[0].fY, pts[1].fY, stopT)); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 313 | } |
| 314 | break; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 315 | case kQuad_SegType: |
| 316 | if (startT == 0) { |
| 317 | if (stopT == SK_Scalar1) { |
| 318 | dst->quadTo(pts[1], pts[2]); |
| 319 | } else { |
| 320 | SkChopQuadAt(pts, tmp0, stopT); |
| 321 | dst->quadTo(tmp0[1], tmp0[2]); |
| 322 | } |
| 323 | } else { |
| 324 | SkChopQuadAt(pts, tmp0, startT); |
| 325 | if (stopT == SK_Scalar1) { |
| 326 | dst->quadTo(tmp0[3], tmp0[4]); |
| 327 | } else { |
| 328 | SkChopQuadAt(&tmp0[2], tmp1, SkScalarDiv(stopT - startT, |
| 329 | SK_Scalar1 - startT)); |
| 330 | dst->quadTo(tmp1[1], tmp1[2]); |
| 331 | } |
| 332 | } |
| 333 | break; |
| 334 | case kCubic_SegType: |
| 335 | if (startT == 0) { |
| 336 | if (stopT == SK_Scalar1) { |
| 337 | dst->cubicTo(pts[1], pts[2], pts[3]); |
| 338 | } else { |
| 339 | SkChopCubicAt(pts, tmp0, stopT); |
| 340 | dst->cubicTo(tmp0[1], tmp0[2], tmp0[3]); |
| 341 | } |
| 342 | } else { |
| 343 | SkChopCubicAt(pts, tmp0, startT); |
| 344 | if (stopT == SK_Scalar1) { |
| 345 | dst->cubicTo(tmp0[4], tmp0[5], tmp0[6]); |
| 346 | } else { |
| 347 | SkChopCubicAt(&tmp0[3], tmp1, SkScalarDiv(stopT - startT, |
| 348 | SK_Scalar1 - startT)); |
| 349 | dst->cubicTo(tmp1[1], tmp1[2], tmp1[3]); |
| 350 | } |
| 351 | } |
| 352 | break; |
| 353 | default: |
tomhudson@google.com | 0c00f21 | 2011-12-28 14:59:50 +0000 | [diff] [blame] | 354 | SkDEBUGFAIL("unknown segType"); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 355 | sk_throw(); |
| 356 | } |
| 357 | } |
| 358 | |
| 359 | //////////////////////////////////////////////////////////////////////////////// |
| 360 | //////////////////////////////////////////////////////////////////////////////// |
| 361 | |
| 362 | SkPathMeasure::SkPathMeasure() { |
| 363 | fPath = NULL; |
| 364 | fLength = -1; // signal we need to compute it |
| 365 | fForceClosed = false; |
| 366 | fFirstPtIndex = -1; |
| 367 | } |
| 368 | |
| 369 | SkPathMeasure::SkPathMeasure(const SkPath& path, bool forceClosed) { |
| 370 | fPath = &path; |
| 371 | fLength = -1; // signal we need to compute it |
| 372 | fForceClosed = forceClosed; |
| 373 | fFirstPtIndex = -1; |
| 374 | |
| 375 | fIter.setPath(path, forceClosed); |
| 376 | } |
| 377 | |
| 378 | SkPathMeasure::~SkPathMeasure() {} |
| 379 | |
| 380 | /** Assign a new path, or null to have none. |
| 381 | */ |
| 382 | void SkPathMeasure::setPath(const SkPath* path, bool forceClosed) { |
| 383 | fPath = path; |
| 384 | fLength = -1; // signal we need to compute it |
| 385 | fForceClosed = forceClosed; |
| 386 | fFirstPtIndex = -1; |
| 387 | |
| 388 | if (path) { |
| 389 | fIter.setPath(*path, forceClosed); |
| 390 | } |
| 391 | fSegments.reset(); |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 392 | fPts.reset(); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 393 | } |
| 394 | |
| 395 | SkScalar SkPathMeasure::getLength() { |
| 396 | if (fPath == NULL) { |
| 397 | return 0; |
| 398 | } |
| 399 | if (fLength < 0) { |
| 400 | this->buildSegments(); |
| 401 | } |
| 402 | SkASSERT(fLength >= 0); |
| 403 | return fLength; |
| 404 | } |
| 405 | |
| 406 | const SkPathMeasure::Segment* SkPathMeasure::distanceToSegment( |
| 407 | SkScalar distance, SkScalar* t) { |
| 408 | SkDEBUGCODE(SkScalar length = ) this->getLength(); |
| 409 | SkASSERT(distance >= 0 && distance <= length); |
| 410 | |
| 411 | const Segment* seg = fSegments.begin(); |
| 412 | int count = fSegments.count(); |
| 413 | |
| 414 | int index = SkTSearch<SkScalar>(&seg->fDistance, count, distance, |
| 415 | sizeof(Segment)); |
| 416 | // don't care if we hit an exact match or not, so we xor index if it is negative |
| 417 | index ^= (index >> 31); |
| 418 | seg = &seg[index]; |
| 419 | |
| 420 | // now interpolate t-values with the prev segment (if possible) |
| 421 | SkScalar startT = 0, startD = 0; |
| 422 | // check if the prev segment is legal, and references the same set of points |
| 423 | if (index > 0) { |
| 424 | startD = seg[-1].fDistance; |
| 425 | if (seg[-1].fPtIndex == seg->fPtIndex) { |
| 426 | SkASSERT(seg[-1].fType == seg->fType); |
| 427 | startT = seg[-1].getScalarT(); |
| 428 | } |
| 429 | } |
| 430 | |
| 431 | SkASSERT(seg->getScalarT() > startT); |
| 432 | SkASSERT(distance >= startD); |
| 433 | SkASSERT(seg->fDistance > startD); |
| 434 | |
| 435 | *t = startT + SkScalarMulDiv(seg->getScalarT() - startT, |
| 436 | distance - startD, |
| 437 | seg->fDistance - startD); |
| 438 | return seg; |
| 439 | } |
| 440 | |
| 441 | bool SkPathMeasure::getPosTan(SkScalar distance, SkPoint* pos, |
| 442 | SkVector* tangent) { |
| 443 | SkASSERT(fPath); |
| 444 | if (fPath == NULL) { |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 445 | return false; |
| 446 | } |
| 447 | |
| 448 | SkScalar length = this->getLength(); // call this to force computing it |
| 449 | int count = fSegments.count(); |
| 450 | |
| 451 | if (count == 0 || length == 0) { |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 452 | return false; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 453 | } |
| 454 | |
| 455 | // pin the distance to a legal range |
| 456 | if (distance < 0) { |
| 457 | distance = 0; |
| 458 | } else if (distance > length) { |
| 459 | distance = length; |
| 460 | } |
| 461 | |
| 462 | SkScalar t; |
| 463 | const Segment* seg = this->distanceToSegment(distance, &t); |
| 464 | |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 465 | compute_pos_tan(fPts, seg->fPtIndex, seg->fType, t, pos, tangent); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 466 | return true; |
| 467 | } |
| 468 | |
| 469 | bool SkPathMeasure::getMatrix(SkScalar distance, SkMatrix* matrix, |
| 470 | MatrixFlags flags) { |
| 471 | SkPoint position; |
| 472 | SkVector tangent; |
| 473 | |
| 474 | if (this->getPosTan(distance, &position, &tangent)) { |
| 475 | if (matrix) { |
| 476 | if (flags & kGetTangent_MatrixFlag) { |
| 477 | matrix->setSinCos(tangent.fY, tangent.fX, 0, 0); |
| 478 | } else { |
| 479 | matrix->reset(); |
| 480 | } |
| 481 | if (flags & kGetPosition_MatrixFlag) { |
| 482 | matrix->postTranslate(position.fX, position.fY); |
| 483 | } |
| 484 | } |
| 485 | return true; |
| 486 | } |
| 487 | return false; |
| 488 | } |
| 489 | |
| 490 | bool SkPathMeasure::getSegment(SkScalar startD, SkScalar stopD, SkPath* dst, |
| 491 | bool startWithMoveTo) { |
| 492 | SkASSERT(dst); |
| 493 | |
| 494 | SkScalar length = this->getLength(); // ensure we have built our segments |
| 495 | |
| 496 | if (startD < 0) { |
| 497 | startD = 0; |
| 498 | } |
| 499 | if (stopD > length) { |
| 500 | stopD = length; |
| 501 | } |
| 502 | if (startD >= stopD) { |
| 503 | return false; |
| 504 | } |
| 505 | |
| 506 | SkPoint p; |
| 507 | SkScalar startT, stopT; |
| 508 | const Segment* seg = this->distanceToSegment(startD, &startT); |
| 509 | const Segment* stopSeg = this->distanceToSegment(stopD, &stopT); |
| 510 | SkASSERT(seg <= stopSeg); |
| 511 | |
| 512 | if (startWithMoveTo) { |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 513 | compute_pos_tan(fPts, seg->fPtIndex, seg->fType, startT, &p, NULL); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 514 | dst->moveTo(p); |
| 515 | } |
| 516 | |
| 517 | if (seg->fPtIndex == stopSeg->fPtIndex) { |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 518 | seg_to(fPts, seg->fPtIndex, seg->fType, startT, stopT, dst); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 519 | } else { |
| 520 | do { |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 521 | seg_to(fPts, seg->fPtIndex, seg->fType, startT, SK_Scalar1, dst); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 522 | seg = SkPathMeasure::NextSegment(seg); |
| 523 | startT = 0; |
| 524 | } while (seg->fPtIndex < stopSeg->fPtIndex); |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 525 | seg_to(fPts, seg->fPtIndex, seg->fType, 0, stopT, dst); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 526 | } |
| 527 | return true; |
| 528 | } |
| 529 | |
| 530 | bool SkPathMeasure::isClosed() { |
| 531 | (void)this->getLength(); |
| 532 | return fIsClosed; |
| 533 | } |
| 534 | |
| 535 | /** Move to the next contour in the path. Return true if one exists, or false if |
| 536 | we're done with the path. |
| 537 | */ |
| 538 | bool SkPathMeasure::nextContour() { |
| 539 | fLength = -1; |
| 540 | return this->getLength() > 0; |
| 541 | } |
| 542 | |
| 543 | /////////////////////////////////////////////////////////////////////////////// |
| 544 | /////////////////////////////////////////////////////////////////////////////// |
| 545 | |
| 546 | #ifdef SK_DEBUG |
| 547 | |
| 548 | void SkPathMeasure::dump() { |
| 549 | SkDebugf("pathmeas: length=%g, segs=%d\n", fLength, fSegments.count()); |
| 550 | |
| 551 | for (int i = 0; i < fSegments.count(); i++) { |
| 552 | const Segment* seg = &fSegments[i]; |
| 553 | SkDebugf("pathmeas: seg[%d] distance=%g, point=%d, t=%g, type=%d\n", |
| 554 | i, seg->fDistance, seg->fPtIndex, seg->getScalarT(), |
| 555 | seg->fType); |
| 556 | } |
| 557 | } |
| 558 | |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 559 | #endif |