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 | |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 54 | // can't use tangents, since we need [0..1..................2] to be seen |
| 55 | // as definitely not a line (it is when drawn, but not parametrically) |
| 56 | // so we compare midpoints |
| 57 | #define CHEAP_DIST_LIMIT (SK_Scalar1/2) // just made this value up |
| 58 | |
| 59 | static bool quad_too_curvy(const SkPoint pts[3]) { |
| 60 | // diff = (a/4 + b/2 + c/4) - (a/2 + c/2) |
| 61 | // diff = -a/4 + b/2 - c/4 |
| 62 | SkScalar dx = SkScalarHalf(pts[1].fX) - |
| 63 | SkScalarHalf(SkScalarHalf(pts[0].fX + pts[2].fX)); |
| 64 | SkScalar dy = SkScalarHalf(pts[1].fY) - |
| 65 | SkScalarHalf(SkScalarHalf(pts[0].fY + pts[2].fY)); |
| 66 | |
| 67 | SkScalar dist = SkMaxScalar(SkScalarAbs(dx), SkScalarAbs(dy)); |
| 68 | return dist > CHEAP_DIST_LIMIT; |
| 69 | } |
| 70 | |
| 71 | static bool cheap_dist_exceeds_limit(const SkPoint& pt, |
| 72 | SkScalar x, SkScalar y) { |
| 73 | SkScalar dist = SkMaxScalar(SkScalarAbs(x - pt.fX), SkScalarAbs(y - pt.fY)); |
| 74 | // just made up the 1/2 |
| 75 | return dist > CHEAP_DIST_LIMIT; |
| 76 | } |
| 77 | |
| 78 | static bool cubic_too_curvy(const SkPoint pts[4]) { |
| 79 | return cheap_dist_exceeds_limit(pts[1], |
| 80 | SkScalarInterp(pts[0].fX, pts[3].fX, SK_Scalar1/3), |
| 81 | SkScalarInterp(pts[0].fY, pts[3].fY, SK_Scalar1/3)) |
| 82 | || |
| 83 | cheap_dist_exceeds_limit(pts[2], |
| 84 | SkScalarInterp(pts[0].fX, pts[3].fX, SK_Scalar1*2/3), |
| 85 | SkScalarInterp(pts[0].fY, pts[3].fY, SK_Scalar1*2/3)); |
| 86 | } |
| 87 | |
| 88 | SkScalar SkPathMeasure::compute_quad_segs(const SkPoint pts[3], |
| 89 | SkScalar distance, int mint, int maxt, int ptIndex) { |
| 90 | if (tspan_big_enough(maxt - mint) && quad_too_curvy(pts)) { |
| 91 | SkPoint tmp[5]; |
| 92 | int halft = (mint + maxt) >> 1; |
| 93 | |
| 94 | SkChopQuadAtHalf(pts, tmp); |
| 95 | distance = this->compute_quad_segs(tmp, distance, mint, halft, ptIndex); |
| 96 | distance = this->compute_quad_segs(&tmp[2], distance, halft, maxt, ptIndex); |
| 97 | } else { |
| 98 | SkScalar d = SkPoint::Distance(pts[0], pts[2]); |
| 99 | SkASSERT(d >= 0); |
reed@google.com | ded4414 | 2012-04-27 20:22:07 +0000 | [diff] [blame] | 100 | if (SkScalarNearlyZero(d)) { |
| 101 | d = 0; |
| 102 | } |
| 103 | SkScalar prevD = distance; |
| 104 | distance += d; |
| 105 | if (distance > prevD) { |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 106 | Segment* seg = fSegments.append(); |
| 107 | seg->fDistance = distance; |
| 108 | seg->fPtIndex = ptIndex; |
| 109 | seg->fType = kQuad_SegType; |
| 110 | seg->fTValue = maxt; |
| 111 | } |
| 112 | } |
| 113 | return distance; |
| 114 | } |
| 115 | |
| 116 | SkScalar SkPathMeasure::compute_cubic_segs(const SkPoint pts[4], |
| 117 | SkScalar distance, int mint, int maxt, int ptIndex) { |
| 118 | if (tspan_big_enough(maxt - mint) && cubic_too_curvy(pts)) { |
| 119 | SkPoint tmp[7]; |
| 120 | int halft = (mint + maxt) >> 1; |
| 121 | |
| 122 | SkChopCubicAtHalf(pts, tmp); |
| 123 | distance = this->compute_cubic_segs(tmp, distance, mint, halft, ptIndex); |
| 124 | distance = this->compute_cubic_segs(&tmp[3], distance, halft, maxt, ptIndex); |
| 125 | } else { |
| 126 | SkScalar d = SkPoint::Distance(pts[0], pts[3]); |
| 127 | SkASSERT(d >= 0); |
reed@google.com | ded4414 | 2012-04-27 20:22:07 +0000 | [diff] [blame] | 128 | if (SkScalarNearlyZero(d)) { |
| 129 | d = 0; |
| 130 | } |
| 131 | SkScalar prevD = distance; |
| 132 | distance += d; |
| 133 | if (distance > prevD) { |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 134 | Segment* seg = fSegments.append(); |
| 135 | seg->fDistance = distance; |
| 136 | seg->fPtIndex = ptIndex; |
| 137 | seg->fType = kCubic_SegType; |
| 138 | seg->fTValue = maxt; |
| 139 | } |
| 140 | } |
| 141 | return distance; |
| 142 | } |
| 143 | |
| 144 | void SkPathMeasure::buildSegments() { |
| 145 | SkPoint pts[4]; |
| 146 | int ptIndex = fFirstPtIndex; |
reed@google.com | fab1ddd | 2012-04-20 15:10:32 +0000 | [diff] [blame] | 147 | SkScalar distance = 0; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 148 | bool isClosed = fForceClosed; |
| 149 | bool firstMoveTo = ptIndex < 0; |
| 150 | Segment* seg; |
| 151 | |
reed@google.com | fab1ddd | 2012-04-20 15:10:32 +0000 | [diff] [blame] | 152 | /* Note: |
| 153 | * as we accumulate distance, we have to check that the result of += |
| 154 | * actually made it larger, since a very small delta might be > 0, but |
| 155 | * still have no effect on distance (if distance >>> delta). |
reed@google.com | ded4414 | 2012-04-27 20:22:07 +0000 | [diff] [blame] | 156 | * |
| 157 | * 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] | 158 | */ |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 159 | fSegments.reset(); |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 160 | bool done = false; |
| 161 | do { |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 162 | switch (fIter.next(pts)) { |
| 163 | case SkPath::kMove_Verb: |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 164 | ptIndex += 1; |
| 165 | fPts.append(1, pts); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 166 | if (!firstMoveTo) { |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 167 | done = true; |
| 168 | break; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 169 | } |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 170 | firstMoveTo = false; |
| 171 | break; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 172 | |
reed@google.com | fab1ddd | 2012-04-20 15:10:32 +0000 | [diff] [blame] | 173 | case SkPath::kLine_Verb: { |
| 174 | SkScalar d = SkPoint::Distance(pts[0], pts[1]); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 175 | SkASSERT(d >= 0); |
reed@google.com | fab1ddd | 2012-04-20 15:10:32 +0000 | [diff] [blame] | 176 | SkScalar prevD = distance; |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 177 | distance += d; |
reed@google.com | fab1ddd | 2012-04-20 15:10:32 +0000 | [diff] [blame] | 178 | if (distance > prevD) { |
| 179 | seg = fSegments.append(); |
| 180 | seg->fDistance = distance; |
| 181 | seg->fPtIndex = ptIndex; |
| 182 | seg->fType = kLine_SegType; |
| 183 | seg->fTValue = kMaxTValue; |
| 184 | fPts.append(1, pts + 1); |
| 185 | ptIndex++; |
| 186 | } |
| 187 | } break; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 188 | |
reed@google.com | fab1ddd | 2012-04-20 15:10:32 +0000 | [diff] [blame] | 189 | case SkPath::kQuad_Verb: { |
| 190 | SkScalar prevD = distance; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 191 | distance = this->compute_quad_segs(pts, distance, 0, |
| 192 | kMaxTValue, ptIndex); |
reed@google.com | fab1ddd | 2012-04-20 15:10:32 +0000 | [diff] [blame] | 193 | if (distance > prevD) { |
| 194 | fPts.append(2, pts + 1); |
| 195 | ptIndex += 2; |
| 196 | } |
| 197 | } break; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 198 | |
reed@google.com | fab1ddd | 2012-04-20 15:10:32 +0000 | [diff] [blame] | 199 | case SkPath::kCubic_Verb: { |
| 200 | SkScalar prevD = distance; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 201 | distance = this->compute_cubic_segs(pts, distance, 0, |
| 202 | kMaxTValue, ptIndex); |
reed@google.com | fab1ddd | 2012-04-20 15:10:32 +0000 | [diff] [blame] | 203 | if (distance > prevD) { |
| 204 | fPts.append(3, pts + 1); |
| 205 | ptIndex += 3; |
| 206 | } |
| 207 | } break; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 208 | |
| 209 | case SkPath::kClose_Verb: |
| 210 | isClosed = true; |
| 211 | break; |
| 212 | |
| 213 | case SkPath::kDone_Verb: |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 214 | done = true; |
| 215 | break; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 216 | } |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 217 | } while (!done); |
| 218 | |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 219 | fLength = distance; |
| 220 | fIsClosed = isClosed; |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 221 | fFirstPtIndex = ptIndex; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 222 | |
| 223 | #ifdef SK_DEBUG |
| 224 | { |
| 225 | const Segment* seg = fSegments.begin(); |
| 226 | const Segment* stop = fSegments.end(); |
| 227 | unsigned ptIndex = 0; |
| 228 | SkScalar distance = 0; |
| 229 | |
| 230 | while (seg < stop) { |
| 231 | SkASSERT(seg->fDistance > distance); |
| 232 | SkASSERT(seg->fPtIndex >= ptIndex); |
| 233 | SkASSERT(seg->fTValue > 0); |
| 234 | |
| 235 | const Segment* s = seg; |
| 236 | while (s < stop - 1 && s[0].fPtIndex == s[1].fPtIndex) { |
| 237 | SkASSERT(s[0].fType == s[1].fType); |
| 238 | SkASSERT(s[0].fTValue < s[1].fTValue); |
| 239 | s += 1; |
| 240 | } |
| 241 | |
| 242 | distance = seg->fDistance; |
| 243 | ptIndex = seg->fPtIndex; |
| 244 | seg += 1; |
| 245 | } |
| 246 | // SkDebugf("\n"); |
| 247 | } |
| 248 | #endif |
| 249 | } |
| 250 | |
reed@google.com | 5b94153 | 2012-05-17 15:31:43 +0000 | [diff] [blame^] | 251 | static void compute_pos_tan(const SkPoint pts[], int segType, |
| 252 | SkScalar t, SkPoint* pos, SkVector* tangent) { |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 253 | switch (segType) { |
| 254 | case kLine_SegType: |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 255 | if (pos) { |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 256 | pos->set(SkScalarInterp(pts[0].fX, pts[1].fX, t), |
reed@google.com | 5b94153 | 2012-05-17 15:31:43 +0000 | [diff] [blame^] | 257 | SkScalarInterp(pts[0].fY, pts[1].fY, t)); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 258 | } |
| 259 | if (tangent) { |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 260 | 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] | 261 | } |
| 262 | break; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 263 | case kQuad_SegType: |
| 264 | SkEvalQuadAt(pts, t, pos, tangent); |
| 265 | if (tangent) { |
| 266 | tangent->normalize(); |
| 267 | } |
| 268 | break; |
| 269 | case kCubic_SegType: |
| 270 | SkEvalCubicAt(pts, t, pos, tangent, NULL); |
| 271 | if (tangent) { |
| 272 | tangent->normalize(); |
| 273 | } |
| 274 | break; |
| 275 | default: |
tomhudson@google.com | 0c00f21 | 2011-12-28 14:59:50 +0000 | [diff] [blame] | 276 | SkDEBUGFAIL("unknown segType"); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 277 | } |
| 278 | } |
| 279 | |
reed@google.com | 5b94153 | 2012-05-17 15:31:43 +0000 | [diff] [blame^] | 280 | static void seg_to(const SkPoint pts[], int segType, |
| 281 | SkScalar startT, SkScalar stopT, SkPath* dst) { |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 282 | SkASSERT(startT >= 0 && startT <= SK_Scalar1); |
| 283 | SkASSERT(stopT >= 0 && stopT <= SK_Scalar1); |
| 284 | SkASSERT(startT <= stopT); |
| 285 | |
| 286 | if (SkScalarNearlyZero(stopT - startT)) { |
| 287 | return; |
| 288 | } |
| 289 | |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 290 | SkPoint tmp0[7], tmp1[7]; |
| 291 | |
| 292 | switch (segType) { |
| 293 | case kLine_SegType: |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 294 | if (stopT == kMaxTValue) { |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 295 | dst->lineTo(pts[1]); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 296 | } else { |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 297 | dst->lineTo(SkScalarInterp(pts[0].fX, pts[1].fX, stopT), |
| 298 | SkScalarInterp(pts[0].fY, pts[1].fY, stopT)); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 299 | } |
| 300 | break; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 301 | case kQuad_SegType: |
| 302 | if (startT == 0) { |
| 303 | if (stopT == SK_Scalar1) { |
| 304 | dst->quadTo(pts[1], pts[2]); |
| 305 | } else { |
| 306 | SkChopQuadAt(pts, tmp0, stopT); |
| 307 | dst->quadTo(tmp0[1], tmp0[2]); |
| 308 | } |
| 309 | } else { |
| 310 | SkChopQuadAt(pts, tmp0, startT); |
| 311 | if (stopT == SK_Scalar1) { |
| 312 | dst->quadTo(tmp0[3], tmp0[4]); |
| 313 | } else { |
| 314 | SkChopQuadAt(&tmp0[2], tmp1, SkScalarDiv(stopT - startT, |
| 315 | SK_Scalar1 - startT)); |
| 316 | dst->quadTo(tmp1[1], tmp1[2]); |
| 317 | } |
| 318 | } |
| 319 | break; |
| 320 | case kCubic_SegType: |
| 321 | if (startT == 0) { |
| 322 | if (stopT == SK_Scalar1) { |
| 323 | dst->cubicTo(pts[1], pts[2], pts[3]); |
| 324 | } else { |
| 325 | SkChopCubicAt(pts, tmp0, stopT); |
| 326 | dst->cubicTo(tmp0[1], tmp0[2], tmp0[3]); |
| 327 | } |
| 328 | } else { |
| 329 | SkChopCubicAt(pts, tmp0, startT); |
| 330 | if (stopT == SK_Scalar1) { |
| 331 | dst->cubicTo(tmp0[4], tmp0[5], tmp0[6]); |
| 332 | } else { |
| 333 | SkChopCubicAt(&tmp0[3], tmp1, SkScalarDiv(stopT - startT, |
| 334 | SK_Scalar1 - startT)); |
| 335 | dst->cubicTo(tmp1[1], tmp1[2], tmp1[3]); |
| 336 | } |
| 337 | } |
| 338 | break; |
| 339 | default: |
tomhudson@google.com | 0c00f21 | 2011-12-28 14:59:50 +0000 | [diff] [blame] | 340 | SkDEBUGFAIL("unknown segType"); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 341 | sk_throw(); |
| 342 | } |
| 343 | } |
| 344 | |
| 345 | //////////////////////////////////////////////////////////////////////////////// |
| 346 | //////////////////////////////////////////////////////////////////////////////// |
| 347 | |
| 348 | SkPathMeasure::SkPathMeasure() { |
| 349 | fPath = NULL; |
| 350 | fLength = -1; // signal we need to compute it |
| 351 | fForceClosed = false; |
| 352 | fFirstPtIndex = -1; |
| 353 | } |
| 354 | |
| 355 | SkPathMeasure::SkPathMeasure(const SkPath& path, bool forceClosed) { |
| 356 | fPath = &path; |
| 357 | fLength = -1; // signal we need to compute it |
| 358 | fForceClosed = forceClosed; |
| 359 | fFirstPtIndex = -1; |
| 360 | |
| 361 | fIter.setPath(path, forceClosed); |
| 362 | } |
| 363 | |
| 364 | SkPathMeasure::~SkPathMeasure() {} |
| 365 | |
| 366 | /** Assign a new path, or null to have none. |
| 367 | */ |
| 368 | void SkPathMeasure::setPath(const SkPath* path, bool forceClosed) { |
| 369 | fPath = path; |
| 370 | fLength = -1; // signal we need to compute it |
| 371 | fForceClosed = forceClosed; |
| 372 | fFirstPtIndex = -1; |
| 373 | |
| 374 | if (path) { |
| 375 | fIter.setPath(*path, forceClosed); |
| 376 | } |
| 377 | fSegments.reset(); |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 378 | fPts.reset(); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 379 | } |
| 380 | |
| 381 | SkScalar SkPathMeasure::getLength() { |
| 382 | if (fPath == NULL) { |
| 383 | return 0; |
| 384 | } |
| 385 | if (fLength < 0) { |
| 386 | this->buildSegments(); |
| 387 | } |
| 388 | SkASSERT(fLength >= 0); |
| 389 | return fLength; |
| 390 | } |
| 391 | |
| 392 | const SkPathMeasure::Segment* SkPathMeasure::distanceToSegment( |
| 393 | SkScalar distance, SkScalar* t) { |
| 394 | SkDEBUGCODE(SkScalar length = ) this->getLength(); |
| 395 | SkASSERT(distance >= 0 && distance <= length); |
| 396 | |
| 397 | const Segment* seg = fSegments.begin(); |
| 398 | int count = fSegments.count(); |
| 399 | |
| 400 | int index = SkTSearch<SkScalar>(&seg->fDistance, count, distance, |
| 401 | sizeof(Segment)); |
| 402 | // don't care if we hit an exact match or not, so we xor index if it is negative |
| 403 | index ^= (index >> 31); |
| 404 | seg = &seg[index]; |
| 405 | |
| 406 | // now interpolate t-values with the prev segment (if possible) |
| 407 | SkScalar startT = 0, startD = 0; |
| 408 | // check if the prev segment is legal, and references the same set of points |
| 409 | if (index > 0) { |
| 410 | startD = seg[-1].fDistance; |
| 411 | if (seg[-1].fPtIndex == seg->fPtIndex) { |
| 412 | SkASSERT(seg[-1].fType == seg->fType); |
| 413 | startT = seg[-1].getScalarT(); |
| 414 | } |
| 415 | } |
| 416 | |
| 417 | SkASSERT(seg->getScalarT() > startT); |
| 418 | SkASSERT(distance >= startD); |
| 419 | SkASSERT(seg->fDistance > startD); |
| 420 | |
| 421 | *t = startT + SkScalarMulDiv(seg->getScalarT() - startT, |
| 422 | distance - startD, |
| 423 | seg->fDistance - startD); |
| 424 | return seg; |
| 425 | } |
| 426 | |
| 427 | bool SkPathMeasure::getPosTan(SkScalar distance, SkPoint* pos, |
| 428 | SkVector* tangent) { |
| 429 | SkASSERT(fPath); |
| 430 | if (fPath == NULL) { |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 431 | return false; |
| 432 | } |
| 433 | |
| 434 | SkScalar length = this->getLength(); // call this to force computing it |
| 435 | int count = fSegments.count(); |
| 436 | |
| 437 | if (count == 0 || length == 0) { |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 438 | return false; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 439 | } |
| 440 | |
| 441 | // pin the distance to a legal range |
| 442 | if (distance < 0) { |
| 443 | distance = 0; |
| 444 | } else if (distance > length) { |
| 445 | distance = length; |
| 446 | } |
| 447 | |
| 448 | SkScalar t; |
| 449 | const Segment* seg = this->distanceToSegment(distance, &t); |
| 450 | |
reed@google.com | 5b94153 | 2012-05-17 15:31:43 +0000 | [diff] [blame^] | 451 | compute_pos_tan(&fPts[seg->fPtIndex], seg->fType, t, pos, tangent); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 452 | return true; |
| 453 | } |
| 454 | |
| 455 | bool SkPathMeasure::getMatrix(SkScalar distance, SkMatrix* matrix, |
| 456 | MatrixFlags flags) { |
| 457 | SkPoint position; |
| 458 | SkVector tangent; |
| 459 | |
| 460 | if (this->getPosTan(distance, &position, &tangent)) { |
| 461 | if (matrix) { |
| 462 | if (flags & kGetTangent_MatrixFlag) { |
| 463 | matrix->setSinCos(tangent.fY, tangent.fX, 0, 0); |
| 464 | } else { |
| 465 | matrix->reset(); |
| 466 | } |
| 467 | if (flags & kGetPosition_MatrixFlag) { |
| 468 | matrix->postTranslate(position.fX, position.fY); |
| 469 | } |
| 470 | } |
| 471 | return true; |
| 472 | } |
| 473 | return false; |
| 474 | } |
| 475 | |
| 476 | bool SkPathMeasure::getSegment(SkScalar startD, SkScalar stopD, SkPath* dst, |
| 477 | bool startWithMoveTo) { |
| 478 | SkASSERT(dst); |
| 479 | |
| 480 | SkScalar length = this->getLength(); // ensure we have built our segments |
| 481 | |
| 482 | if (startD < 0) { |
| 483 | startD = 0; |
| 484 | } |
| 485 | if (stopD > length) { |
| 486 | stopD = length; |
| 487 | } |
| 488 | if (startD >= stopD) { |
| 489 | return false; |
| 490 | } |
| 491 | |
| 492 | SkPoint p; |
| 493 | SkScalar startT, stopT; |
| 494 | const Segment* seg = this->distanceToSegment(startD, &startT); |
| 495 | const Segment* stopSeg = this->distanceToSegment(stopD, &stopT); |
| 496 | SkASSERT(seg <= stopSeg); |
| 497 | |
| 498 | if (startWithMoveTo) { |
reed@google.com | 5b94153 | 2012-05-17 15:31:43 +0000 | [diff] [blame^] | 499 | compute_pos_tan(&fPts[seg->fPtIndex], seg->fType, startT, &p, NULL); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 500 | dst->moveTo(p); |
| 501 | } |
| 502 | |
| 503 | if (seg->fPtIndex == stopSeg->fPtIndex) { |
reed@google.com | 5b94153 | 2012-05-17 15:31:43 +0000 | [diff] [blame^] | 504 | seg_to(&fPts[seg->fPtIndex], seg->fType, startT, stopT, dst); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 505 | } else { |
| 506 | do { |
reed@google.com | 5b94153 | 2012-05-17 15:31:43 +0000 | [diff] [blame^] | 507 | seg_to(&fPts[seg->fPtIndex], seg->fType, startT, SK_Scalar1, dst); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 508 | seg = SkPathMeasure::NextSegment(seg); |
| 509 | startT = 0; |
| 510 | } while (seg->fPtIndex < stopSeg->fPtIndex); |
reed@google.com | 5b94153 | 2012-05-17 15:31:43 +0000 | [diff] [blame^] | 511 | seg_to(&fPts[seg->fPtIndex], seg->fType, 0, stopT, dst); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 512 | } |
| 513 | return true; |
| 514 | } |
| 515 | |
| 516 | bool SkPathMeasure::isClosed() { |
| 517 | (void)this->getLength(); |
| 518 | return fIsClosed; |
| 519 | } |
| 520 | |
| 521 | /** Move to the next contour in the path. Return true if one exists, or false if |
| 522 | we're done with the path. |
| 523 | */ |
| 524 | bool SkPathMeasure::nextContour() { |
| 525 | fLength = -1; |
| 526 | return this->getLength() > 0; |
| 527 | } |
| 528 | |
| 529 | /////////////////////////////////////////////////////////////////////////////// |
| 530 | /////////////////////////////////////////////////////////////////////////////// |
| 531 | |
| 532 | #ifdef SK_DEBUG |
| 533 | |
| 534 | void SkPathMeasure::dump() { |
| 535 | SkDebugf("pathmeas: length=%g, segs=%d\n", fLength, fSegments.count()); |
| 536 | |
| 537 | for (int i = 0; i < fSegments.count(); i++) { |
| 538 | const Segment* seg = &fSegments[i]; |
| 539 | SkDebugf("pathmeas: seg[%d] distance=%g, point=%d, t=%g, type=%d\n", |
| 540 | i, seg->fDistance, seg->fPtIndex, seg->getScalarT(), |
| 541 | seg->fType); |
| 542 | } |
| 543 | } |
| 544 | |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 545 | #endif |