1 /* 2 * Copyright 2006 The Android Open Source Project 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8 9 #include "Sk1DPathEffect.h" 10 #include "SkReadBuffer.h" 11 #include "SkWriteBuffer.h" 12 #include "SkPathMeasure.h" 13 #include "SkStrokeRec.h" 14 15 bool Sk1DPathEffect::filterPath(SkPath* dst, const SkPath& src, 16 SkStrokeRec*, const SkRect*) const { 17 SkPathMeasure meas(src, false); 18 do { 19 SkScalar length = meas.getLength(); 20 SkScalar distance = this->begin(length); 21 while (distance < length) { 22 SkScalar delta = this->next(dst, distance, meas); 23 if (delta <= 0) { 24 break; 25 } 26 distance += delta; 27 } 28 } while (meas.nextContour()); 29 return true; 30 } 31 32 /////////////////////////////////////////////////////////////////////////////// 33 34 SkPath1DPathEffect::SkPath1DPathEffect(const SkPath& path, SkScalar advance, 35 SkScalar phase, Style style) : fPath(path) 36 { 37 SkASSERT(advance > 0 && !path.isEmpty()); 38 // cleanup their phase parameter, inverting it so that it becomes an 39 // offset along the path (to match the interpretation in PostScript) 40 if (phase < 0) { 41 phase = -phase; 42 if (phase > advance) { 43 phase = SkScalarMod(phase, advance); 44 } 45 } else { 46 if (phase > advance) { 47 phase = SkScalarMod(phase, advance); 48 } 49 phase = advance - phase; 50 } 51 // now catch the edge case where phase == advance (within epsilon) 52 if (phase >= advance) { 53 phase = 0; 54 } 55 SkASSERT(phase >= 0); 56 57 fAdvance = advance; 58 fInitialOffset = phase; 59 60 if ((unsigned)style > kMorph_Style) { 61 SkDEBUGF(("SkPath1DPathEffect style enum out of range %d\n", style)); 62 } 63 fStyle = style; 64 } 65 66 bool SkPath1DPathEffect::filterPath(SkPath* dst, const SkPath& src, 67 SkStrokeRec* rec, const SkRect* cullRect) const { 68 if (fAdvance > 0) { 69 rec->setFillStyle(); 70 return this->INHERITED::filterPath(dst, src, rec, cullRect); 71 } 72 return false; 73 } 74 75 static bool morphpoints(SkPoint dst[], const SkPoint src[], int count, 76 SkPathMeasure& meas, SkScalar dist) { 77 for (int i = 0; i < count; i++) { 78 SkPoint pos; 79 SkVector tangent; 80 81 SkScalar sx = src[i].fX; 82 SkScalar sy = src[i].fY; 83 84 if (!meas.getPosTan(dist + sx, &pos, &tangent)) { 85 return false; 86 } 87 88 SkMatrix matrix; 89 SkPoint pt; 90 91 pt.set(sx, sy); 92 matrix.setSinCos(tangent.fY, tangent.fX, 0, 0); 93 matrix.preTranslate(-sx, 0); 94 matrix.postTranslate(pos.fX, pos.fY); 95 matrix.mapPoints(&dst[i], &pt, 1); 96 } 97 return true; 98 } 99 100 /* TODO 101 102 Need differentially more subdivisions when the follow-path is curvy. Not sure how to 103 determine that, but we need it. I guess a cheap answer is let the caller tell us, 104 but that seems like a cop-out. Another answer is to get Rob Johnson to figure it out. 105 */ 106 static void morphpath(SkPath* dst, const SkPath& src, SkPathMeasure& meas, 107 SkScalar dist) { 108 SkPath::Iter iter(src, false); 109 SkPoint srcP[4], dstP[3]; 110 SkPath::Verb verb; 111 112 while ((verb = iter.next(srcP)) != SkPath::kDone_Verb) { 113 switch (verb) { 114 case SkPath::kMove_Verb: 115 if (morphpoints(dstP, srcP, 1, meas, dist)) { 116 dst->moveTo(dstP[0]); 117 } 118 break; 119 case SkPath::kLine_Verb: 120 srcP[2] = srcP[1]; 121 srcP[1].set(SkScalarAve(srcP[0].fX, srcP[2].fX), 122 SkScalarAve(srcP[0].fY, srcP[2].fY)); 123 // fall through to quad 124 case SkPath::kQuad_Verb: 125 if (morphpoints(dstP, &srcP[1], 2, meas, dist)) { 126 dst->quadTo(dstP[0], dstP[1]); 127 } 128 break; 129 case SkPath::kCubic_Verb: 130 if (morphpoints(dstP, &srcP[1], 3, meas, dist)) { 131 dst->cubicTo(dstP[0], dstP[1], dstP[2]); 132 } 133 break; 134 case SkPath::kClose_Verb: 135 dst->close(); 136 break; 137 default: 138 SkDEBUGFAIL("unknown verb"); 139 break; 140 } 141 } 142 } 143 144 SkScalar SkPath1DPathEffect::begin(SkScalar contourLength) const { 145 return fInitialOffset; 146 } 147 148 sk_sp<SkFlattenable> SkPath1DPathEffect::CreateProc(SkReadBuffer& buffer) { 149 SkScalar advance = buffer.readScalar(); 150 if (advance > 0) { 151 SkPath path; 152 buffer.readPath(&path); 153 SkScalar phase = buffer.readScalar(); 154 Style style = (Style)buffer.readUInt(); 155 return SkPath1DPathEffect::Make(path, advance, phase, style); 156 } 157 return nullptr; 158 } 159 160 void SkPath1DPathEffect::flatten(SkWriteBuffer& buffer) const { 161 buffer.writeScalar(fAdvance); 162 if (fAdvance > 0) { 163 buffer.writePath(fPath); 164 buffer.writeScalar(fInitialOffset); 165 buffer.writeUInt(fStyle); 166 } 167 } 168 169 SkScalar SkPath1DPathEffect::next(SkPath* dst, SkScalar distance, 170 SkPathMeasure& meas) const { 171 switch (fStyle) { 172 case kTranslate_Style: { 173 SkPoint pos; 174 if (meas.getPosTan(distance, &pos, nullptr)) { 175 dst->addPath(fPath, pos.fX, pos.fY); 176 } 177 } break; 178 case kRotate_Style: { 179 SkMatrix matrix; 180 if (meas.getMatrix(distance, &matrix)) { 181 dst->addPath(fPath, matrix); 182 } 183 } break; 184 case kMorph_Style: 185 morphpath(dst, fPath, meas, distance); 186 break; 187 default: 188 SkDEBUGFAIL("unknown Style enum"); 189 break; 190 } 191 return fAdvance; 192 } 193 194 195 #ifndef SK_IGNORE_TO_STRING 196 void SkPath1DPathEffect::toString(SkString* str) const { 197 str->appendf("SkPath1DPathEffect: ("); 198 // TODO: add path and style 199 str->appendf("advance: %.2f phase %.2f", fAdvance, fInitialOffset); 200 str->appendf(")"); 201 } 202 #endif 203 204 /////////////////////////////////////////////////////////////////////////////////////////////////// 205 206 sk_sp<SkPathEffect> SkPath1DPathEffect::Make(const SkPath& path, SkScalar advance, SkScalar phase, 207 Style style) { 208 if (advance <= 0 || !SkScalarIsFinite(advance) || 209 !SkScalarIsFinite(phase) || path.isEmpty()) { 210 return nullptr; 211 } 212 return sk_sp<SkPathEffect>(new SkPath1DPathEffect(path, advance, phase, style)); 213 } 214
