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
filterPath(SkPath * dst,const SkPath & src,SkStrokeRec *,const SkRect *) const15 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
SkPath1DPathEffect(const SkPath & path,SkScalar advance,SkScalar phase,Style style)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
filterPath(SkPath * dst,const SkPath & src,SkStrokeRec * rec,const SkRect * cullRect) const66 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
morphpoints(SkPoint dst[],const SkPoint src[],int count,SkPathMeasure & meas,SkScalar dist)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 */
morphpath(SkPath * dst,const SkPath & src,SkPathMeasure & meas,SkScalar dist)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
begin(SkScalar contourLength) const144 SkScalar SkPath1DPathEffect::begin(SkScalar contourLength) const {
145 return fInitialOffset;
146 }
147
CreateProc(SkReadBuffer & buffer)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
flatten(SkWriteBuffer & buffer) const160 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
next(SkPath * dst,SkScalar distance,SkPathMeasure & meas) const169 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
toString(SkString * str) const196 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
Make(const SkPath & path,SkScalar advance,SkScalar phase,Style style)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