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]); |
reed@google.com | ded4414 | 2012-04-27 20:22:07 +0000 | [diff] [blame] | 99 | SkScalar prevD = distance; |
| 100 | distance += d; |
| 101 | if (distance > prevD) { |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 102 | Segment* seg = fSegments.append(); |
| 103 | seg->fDistance = distance; |
| 104 | seg->fPtIndex = ptIndex; |
| 105 | seg->fType = kQuad_SegType; |
| 106 | seg->fTValue = maxt; |
| 107 | } |
| 108 | } |
| 109 | return distance; |
| 110 | } |
| 111 | |
| 112 | SkScalar SkPathMeasure::compute_cubic_segs(const SkPoint pts[4], |
| 113 | SkScalar distance, int mint, int maxt, int ptIndex) { |
| 114 | if (tspan_big_enough(maxt - mint) && cubic_too_curvy(pts)) { |
| 115 | SkPoint tmp[7]; |
| 116 | int halft = (mint + maxt) >> 1; |
| 117 | |
| 118 | SkChopCubicAtHalf(pts, tmp); |
| 119 | distance = this->compute_cubic_segs(tmp, distance, mint, halft, ptIndex); |
| 120 | distance = this->compute_cubic_segs(&tmp[3], distance, halft, maxt, ptIndex); |
| 121 | } else { |
| 122 | SkScalar d = SkPoint::Distance(pts[0], pts[3]); |
reed@google.com | ded4414 | 2012-04-27 20:22:07 +0000 | [diff] [blame] | 123 | SkScalar prevD = distance; |
| 124 | distance += d; |
| 125 | if (distance > prevD) { |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 126 | Segment* seg = fSegments.append(); |
| 127 | seg->fDistance = distance; |
| 128 | seg->fPtIndex = ptIndex; |
| 129 | seg->fType = kCubic_SegType; |
| 130 | seg->fTValue = maxt; |
| 131 | } |
| 132 | } |
| 133 | return distance; |
| 134 | } |
| 135 | |
| 136 | void SkPathMeasure::buildSegments() { |
| 137 | SkPoint pts[4]; |
| 138 | int ptIndex = fFirstPtIndex; |
reed@google.com | fab1ddd | 2012-04-20 15:10:32 +0000 | [diff] [blame] | 139 | SkScalar distance = 0; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 140 | bool isClosed = fForceClosed; |
| 141 | bool firstMoveTo = ptIndex < 0; |
| 142 | Segment* seg; |
| 143 | |
reed@google.com | fab1ddd | 2012-04-20 15:10:32 +0000 | [diff] [blame] | 144 | /* Note: |
| 145 | * as we accumulate distance, we have to check that the result of += |
| 146 | * actually made it larger, since a very small delta might be > 0, but |
| 147 | * still have no effect on distance (if distance >>> delta). |
reed@google.com | ded4414 | 2012-04-27 20:22:07 +0000 | [diff] [blame] | 148 | * |
| 149 | * 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] | 150 | */ |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 151 | fSegments.reset(); |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 152 | bool done = false; |
| 153 | do { |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 154 | switch (fIter.next(pts)) { |
| 155 | case SkPath::kMove_Verb: |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 156 | ptIndex += 1; |
| 157 | fPts.append(1, pts); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 158 | if (!firstMoveTo) { |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 159 | done = true; |
| 160 | break; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 161 | } |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 162 | firstMoveTo = false; |
| 163 | break; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 164 | |
reed@google.com | fab1ddd | 2012-04-20 15:10:32 +0000 | [diff] [blame] | 165 | case SkPath::kLine_Verb: { |
| 166 | SkScalar d = SkPoint::Distance(pts[0], pts[1]); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 167 | SkASSERT(d >= 0); |
reed@google.com | fab1ddd | 2012-04-20 15:10:32 +0000 | [diff] [blame] | 168 | SkScalar prevD = distance; |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 169 | distance += d; |
reed@google.com | fab1ddd | 2012-04-20 15:10:32 +0000 | [diff] [blame] | 170 | if (distance > prevD) { |
| 171 | seg = fSegments.append(); |
| 172 | seg->fDistance = distance; |
| 173 | seg->fPtIndex = ptIndex; |
| 174 | seg->fType = kLine_SegType; |
| 175 | seg->fTValue = kMaxTValue; |
| 176 | fPts.append(1, pts + 1); |
| 177 | ptIndex++; |
| 178 | } |
| 179 | } break; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 180 | |
reed@google.com | fab1ddd | 2012-04-20 15:10:32 +0000 | [diff] [blame] | 181 | case SkPath::kQuad_Verb: { |
| 182 | SkScalar prevD = distance; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 183 | distance = this->compute_quad_segs(pts, distance, 0, |
| 184 | kMaxTValue, ptIndex); |
reed@google.com | fab1ddd | 2012-04-20 15:10:32 +0000 | [diff] [blame] | 185 | if (distance > prevD) { |
| 186 | fPts.append(2, pts + 1); |
| 187 | ptIndex += 2; |
| 188 | } |
| 189 | } break; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 190 | |
reed@google.com | fab1ddd | 2012-04-20 15:10:32 +0000 | [diff] [blame] | 191 | case SkPath::kCubic_Verb: { |
| 192 | SkScalar prevD = distance; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 193 | distance = this->compute_cubic_segs(pts, distance, 0, |
| 194 | kMaxTValue, ptIndex); |
reed@google.com | fab1ddd | 2012-04-20 15:10:32 +0000 | [diff] [blame] | 195 | if (distance > prevD) { |
| 196 | fPts.append(3, pts + 1); |
| 197 | ptIndex += 3; |
| 198 | } |
| 199 | } break; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 200 | |
| 201 | case SkPath::kClose_Verb: |
| 202 | isClosed = true; |
| 203 | break; |
rmistry@google.com | fbfcd56 | 2012-08-23 18:09:54 +0000 | [diff] [blame] | 204 | |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 205 | case SkPath::kDone_Verb: |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 206 | done = true; |
| 207 | break; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 208 | } |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 209 | } while (!done); |
| 210 | |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 211 | fLength = distance; |
| 212 | fIsClosed = isClosed; |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 213 | fFirstPtIndex = ptIndex; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 214 | |
| 215 | #ifdef SK_DEBUG |
| 216 | { |
| 217 | const Segment* seg = fSegments.begin(); |
| 218 | const Segment* stop = fSegments.end(); |
| 219 | unsigned ptIndex = 0; |
| 220 | SkScalar distance = 0; |
| 221 | |
| 222 | while (seg < stop) { |
| 223 | SkASSERT(seg->fDistance > distance); |
| 224 | SkASSERT(seg->fPtIndex >= ptIndex); |
| 225 | SkASSERT(seg->fTValue > 0); |
| 226 | |
| 227 | const Segment* s = seg; |
| 228 | while (s < stop - 1 && s[0].fPtIndex == s[1].fPtIndex) { |
| 229 | SkASSERT(s[0].fType == s[1].fType); |
| 230 | SkASSERT(s[0].fTValue < s[1].fTValue); |
| 231 | s += 1; |
| 232 | } |
| 233 | |
| 234 | distance = seg->fDistance; |
| 235 | ptIndex = seg->fPtIndex; |
| 236 | seg += 1; |
| 237 | } |
| 238 | // SkDebugf("\n"); |
| 239 | } |
| 240 | #endif |
| 241 | } |
| 242 | |
reed@google.com | 5b94153 | 2012-05-17 15:31:43 +0000 | [diff] [blame] | 243 | static void compute_pos_tan(const SkPoint pts[], int segType, |
| 244 | SkScalar t, SkPoint* pos, SkVector* tangent) { |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 245 | switch (segType) { |
| 246 | case kLine_SegType: |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 247 | if (pos) { |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 248 | pos->set(SkScalarInterp(pts[0].fX, pts[1].fX, t), |
reed@google.com | 5b94153 | 2012-05-17 15:31:43 +0000 | [diff] [blame] | 249 | SkScalarInterp(pts[0].fY, pts[1].fY, t)); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 250 | } |
| 251 | if (tangent) { |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 252 | 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] | 253 | } |
| 254 | break; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 255 | case kQuad_SegType: |
| 256 | SkEvalQuadAt(pts, t, pos, tangent); |
| 257 | if (tangent) { |
| 258 | tangent->normalize(); |
| 259 | } |
| 260 | break; |
| 261 | case kCubic_SegType: |
| 262 | SkEvalCubicAt(pts, t, pos, tangent, NULL); |
| 263 | if (tangent) { |
| 264 | tangent->normalize(); |
| 265 | } |
| 266 | break; |
| 267 | default: |
tomhudson@google.com | 0c00f21 | 2011-12-28 14:59:50 +0000 | [diff] [blame] | 268 | SkDEBUGFAIL("unknown segType"); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 269 | } |
| 270 | } |
| 271 | |
reed@google.com | 5b94153 | 2012-05-17 15:31:43 +0000 | [diff] [blame] | 272 | static void seg_to(const SkPoint pts[], int segType, |
| 273 | SkScalar startT, SkScalar stopT, SkPath* dst) { |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 274 | SkASSERT(startT >= 0 && startT <= SK_Scalar1); |
| 275 | SkASSERT(stopT >= 0 && stopT <= SK_Scalar1); |
| 276 | SkASSERT(startT <= stopT); |
| 277 | |
reed@google.com | de1837b | 2012-05-21 16:47:43 +0000 | [diff] [blame] | 278 | if (startT == stopT) { |
| 279 | return; // should we report this, to undo a moveTo? |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 280 | } |
| 281 | |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 282 | SkPoint tmp0[7], tmp1[7]; |
| 283 | |
| 284 | switch (segType) { |
| 285 | case kLine_SegType: |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 286 | if (stopT == kMaxTValue) { |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 287 | dst->lineTo(pts[1]); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 288 | } else { |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 289 | dst->lineTo(SkScalarInterp(pts[0].fX, pts[1].fX, stopT), |
| 290 | SkScalarInterp(pts[0].fY, pts[1].fY, stopT)); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 291 | } |
| 292 | break; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 293 | case kQuad_SegType: |
| 294 | if (startT == 0) { |
| 295 | if (stopT == SK_Scalar1) { |
| 296 | dst->quadTo(pts[1], pts[2]); |
| 297 | } else { |
| 298 | SkChopQuadAt(pts, tmp0, stopT); |
| 299 | dst->quadTo(tmp0[1], tmp0[2]); |
| 300 | } |
| 301 | } else { |
| 302 | SkChopQuadAt(pts, tmp0, startT); |
| 303 | if (stopT == SK_Scalar1) { |
| 304 | dst->quadTo(tmp0[3], tmp0[4]); |
| 305 | } else { |
| 306 | SkChopQuadAt(&tmp0[2], tmp1, SkScalarDiv(stopT - startT, |
| 307 | SK_Scalar1 - startT)); |
| 308 | dst->quadTo(tmp1[1], tmp1[2]); |
| 309 | } |
| 310 | } |
| 311 | break; |
| 312 | case kCubic_SegType: |
| 313 | if (startT == 0) { |
| 314 | if (stopT == SK_Scalar1) { |
| 315 | dst->cubicTo(pts[1], pts[2], pts[3]); |
| 316 | } else { |
| 317 | SkChopCubicAt(pts, tmp0, stopT); |
| 318 | dst->cubicTo(tmp0[1], tmp0[2], tmp0[3]); |
| 319 | } |
| 320 | } else { |
| 321 | SkChopCubicAt(pts, tmp0, startT); |
| 322 | if (stopT == SK_Scalar1) { |
| 323 | dst->cubicTo(tmp0[4], tmp0[5], tmp0[6]); |
| 324 | } else { |
| 325 | SkChopCubicAt(&tmp0[3], tmp1, SkScalarDiv(stopT - startT, |
| 326 | SK_Scalar1 - startT)); |
| 327 | dst->cubicTo(tmp1[1], tmp1[2], tmp1[3]); |
| 328 | } |
| 329 | } |
| 330 | break; |
| 331 | default: |
tomhudson@google.com | 0c00f21 | 2011-12-28 14:59:50 +0000 | [diff] [blame] | 332 | SkDEBUGFAIL("unknown segType"); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 333 | sk_throw(); |
| 334 | } |
| 335 | } |
| 336 | |
| 337 | //////////////////////////////////////////////////////////////////////////////// |
| 338 | //////////////////////////////////////////////////////////////////////////////// |
| 339 | |
| 340 | SkPathMeasure::SkPathMeasure() { |
| 341 | fPath = NULL; |
| 342 | fLength = -1; // signal we need to compute it |
| 343 | fForceClosed = false; |
| 344 | fFirstPtIndex = -1; |
| 345 | } |
| 346 | |
| 347 | SkPathMeasure::SkPathMeasure(const SkPath& path, bool forceClosed) { |
| 348 | fPath = &path; |
| 349 | fLength = -1; // signal we need to compute it |
| 350 | fForceClosed = forceClosed; |
| 351 | fFirstPtIndex = -1; |
| 352 | |
| 353 | fIter.setPath(path, forceClosed); |
| 354 | } |
| 355 | |
| 356 | SkPathMeasure::~SkPathMeasure() {} |
| 357 | |
| 358 | /** Assign a new path, or null to have none. |
| 359 | */ |
| 360 | void SkPathMeasure::setPath(const SkPath* path, bool forceClosed) { |
| 361 | fPath = path; |
| 362 | fLength = -1; // signal we need to compute it |
| 363 | fForceClosed = forceClosed; |
| 364 | fFirstPtIndex = -1; |
| 365 | |
| 366 | if (path) { |
| 367 | fIter.setPath(*path, forceClosed); |
| 368 | } |
| 369 | fSegments.reset(); |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 370 | fPts.reset(); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 371 | } |
| 372 | |
| 373 | SkScalar SkPathMeasure::getLength() { |
| 374 | if (fPath == NULL) { |
| 375 | return 0; |
| 376 | } |
| 377 | if (fLength < 0) { |
| 378 | this->buildSegments(); |
| 379 | } |
| 380 | SkASSERT(fLength >= 0); |
| 381 | return fLength; |
| 382 | } |
| 383 | |
| 384 | const SkPathMeasure::Segment* SkPathMeasure::distanceToSegment( |
| 385 | SkScalar distance, SkScalar* t) { |
| 386 | SkDEBUGCODE(SkScalar length = ) this->getLength(); |
| 387 | SkASSERT(distance >= 0 && distance <= length); |
| 388 | |
| 389 | const Segment* seg = fSegments.begin(); |
| 390 | int count = fSegments.count(); |
| 391 | |
| 392 | int index = SkTSearch<SkScalar>(&seg->fDistance, count, distance, |
| 393 | sizeof(Segment)); |
| 394 | // don't care if we hit an exact match or not, so we xor index if it is negative |
| 395 | index ^= (index >> 31); |
| 396 | seg = &seg[index]; |
| 397 | |
| 398 | // now interpolate t-values with the prev segment (if possible) |
| 399 | SkScalar startT = 0, startD = 0; |
| 400 | // check if the prev segment is legal, and references the same set of points |
| 401 | if (index > 0) { |
| 402 | startD = seg[-1].fDistance; |
| 403 | if (seg[-1].fPtIndex == seg->fPtIndex) { |
| 404 | SkASSERT(seg[-1].fType == seg->fType); |
| 405 | startT = seg[-1].getScalarT(); |
| 406 | } |
| 407 | } |
| 408 | |
| 409 | SkASSERT(seg->getScalarT() > startT); |
| 410 | SkASSERT(distance >= startD); |
| 411 | SkASSERT(seg->fDistance > startD); |
| 412 | |
| 413 | *t = startT + SkScalarMulDiv(seg->getScalarT() - startT, |
| 414 | distance - startD, |
| 415 | seg->fDistance - startD); |
| 416 | return seg; |
| 417 | } |
| 418 | |
| 419 | bool SkPathMeasure::getPosTan(SkScalar distance, SkPoint* pos, |
| 420 | SkVector* tangent) { |
djsollen@google.com | dfef456 | 2012-11-01 12:15:12 +0000 | [diff] [blame^] | 421 | if (NULL == fPath) { |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 422 | return false; |
| 423 | } |
| 424 | |
| 425 | SkScalar length = this->getLength(); // call this to force computing it |
| 426 | int count = fSegments.count(); |
| 427 | |
| 428 | if (count == 0 || length == 0) { |
schenney@chromium.org | a6d04d9 | 2012-01-18 18:02:10 +0000 | [diff] [blame] | 429 | return false; |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 430 | } |
| 431 | |
| 432 | // pin the distance to a legal range |
| 433 | if (distance < 0) { |
| 434 | distance = 0; |
| 435 | } else if (distance > length) { |
| 436 | distance = length; |
| 437 | } |
rmistry@google.com | fbfcd56 | 2012-08-23 18:09:54 +0000 | [diff] [blame] | 438 | |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 439 | SkScalar t; |
| 440 | const Segment* seg = this->distanceToSegment(distance, &t); |
| 441 | |
reed@google.com | 5b94153 | 2012-05-17 15:31:43 +0000 | [diff] [blame] | 442 | compute_pos_tan(&fPts[seg->fPtIndex], seg->fType, t, pos, tangent); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 443 | return true; |
| 444 | } |
| 445 | |
| 446 | bool SkPathMeasure::getMatrix(SkScalar distance, SkMatrix* matrix, |
| 447 | MatrixFlags flags) { |
djsollen@google.com | dfef456 | 2012-11-01 12:15:12 +0000 | [diff] [blame^] | 448 | if (NULL == fPath) { |
| 449 | return false; |
| 450 | } |
| 451 | |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 452 | SkPoint position; |
| 453 | SkVector tangent; |
| 454 | |
| 455 | if (this->getPosTan(distance, &position, &tangent)) { |
| 456 | if (matrix) { |
| 457 | if (flags & kGetTangent_MatrixFlag) { |
| 458 | matrix->setSinCos(tangent.fY, tangent.fX, 0, 0); |
| 459 | } else { |
| 460 | matrix->reset(); |
| 461 | } |
| 462 | if (flags & kGetPosition_MatrixFlag) { |
| 463 | matrix->postTranslate(position.fX, position.fY); |
| 464 | } |
| 465 | } |
| 466 | return true; |
| 467 | } |
| 468 | return false; |
| 469 | } |
| 470 | |
| 471 | bool SkPathMeasure::getSegment(SkScalar startD, SkScalar stopD, SkPath* dst, |
| 472 | bool startWithMoveTo) { |
| 473 | SkASSERT(dst); |
| 474 | |
| 475 | SkScalar length = this->getLength(); // ensure we have built our segments |
| 476 | |
| 477 | if (startD < 0) { |
| 478 | startD = 0; |
| 479 | } |
| 480 | if (stopD > length) { |
| 481 | stopD = length; |
| 482 | } |
| 483 | if (startD >= stopD) { |
| 484 | return false; |
| 485 | } |
| 486 | |
| 487 | SkPoint p; |
| 488 | SkScalar startT, stopT; |
| 489 | const Segment* seg = this->distanceToSegment(startD, &startT); |
| 490 | const Segment* stopSeg = this->distanceToSegment(stopD, &stopT); |
| 491 | SkASSERT(seg <= stopSeg); |
| 492 | |
| 493 | if (startWithMoveTo) { |
reed@google.com | 5b94153 | 2012-05-17 15:31:43 +0000 | [diff] [blame] | 494 | compute_pos_tan(&fPts[seg->fPtIndex], seg->fType, startT, &p, NULL); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 495 | dst->moveTo(p); |
| 496 | } |
| 497 | |
| 498 | if (seg->fPtIndex == stopSeg->fPtIndex) { |
reed@google.com | 5b94153 | 2012-05-17 15:31:43 +0000 | [diff] [blame] | 499 | seg_to(&fPts[seg->fPtIndex], seg->fType, startT, stopT, dst); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 500 | } else { |
| 501 | do { |
reed@google.com | 5b94153 | 2012-05-17 15:31:43 +0000 | [diff] [blame] | 502 | seg_to(&fPts[seg->fPtIndex], seg->fType, startT, SK_Scalar1, dst); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 503 | seg = SkPathMeasure::NextSegment(seg); |
| 504 | startT = 0; |
| 505 | } while (seg->fPtIndex < stopSeg->fPtIndex); |
reed@google.com | 5b94153 | 2012-05-17 15:31:43 +0000 | [diff] [blame] | 506 | seg_to(&fPts[seg->fPtIndex], seg->fType, 0, stopT, dst); |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 507 | } |
| 508 | return true; |
| 509 | } |
| 510 | |
| 511 | bool SkPathMeasure::isClosed() { |
| 512 | (void)this->getLength(); |
| 513 | return fIsClosed; |
| 514 | } |
| 515 | |
| 516 | /** Move to the next contour in the path. Return true if one exists, or false if |
| 517 | we're done with the path. |
| 518 | */ |
| 519 | bool SkPathMeasure::nextContour() { |
| 520 | fLength = -1; |
| 521 | return this->getLength() > 0; |
| 522 | } |
| 523 | |
| 524 | /////////////////////////////////////////////////////////////////////////////// |
| 525 | /////////////////////////////////////////////////////////////////////////////// |
| 526 | |
| 527 | #ifdef SK_DEBUG |
| 528 | |
| 529 | void SkPathMeasure::dump() { |
| 530 | SkDebugf("pathmeas: length=%g, segs=%d\n", fLength, fSegments.count()); |
| 531 | |
| 532 | for (int i = 0; i < fSegments.count(); i++) { |
| 533 | const Segment* seg = &fSegments[i]; |
| 534 | SkDebugf("pathmeas: seg[%d] distance=%g, point=%d, t=%g, type=%d\n", |
| 535 | i, seg->fDistance, seg->fPtIndex, seg->getScalarT(), |
| 536 | seg->fType); |
| 537 | } |
| 538 | } |
| 539 | |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 540 | #endif |