1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/skia/trunk/src/effects/Sk1DPathEffect.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,201 @@
1.4 +
1.5 +/*
1.6 + * Copyright 2006 The Android Open Source Project
1.7 + *
1.8 + * Use of this source code is governed by a BSD-style license that can be
1.9 + * found in the LICENSE file.
1.10 + */
1.11 +
1.12 +
1.13 +#include "Sk1DPathEffect.h"
1.14 +#include "SkReadBuffer.h"
1.15 +#include "SkWriteBuffer.h"
1.16 +#include "SkPathMeasure.h"
1.17 +
1.18 +bool Sk1DPathEffect::filterPath(SkPath* dst, const SkPath& src,
1.19 + SkStrokeRec*, const SkRect*) const {
1.20 + SkPathMeasure meas(src, false);
1.21 + do {
1.22 + SkScalar length = meas.getLength();
1.23 + SkScalar distance = this->begin(length);
1.24 + while (distance < length) {
1.25 + SkScalar delta = this->next(dst, distance, meas);
1.26 + if (delta <= 0) {
1.27 + break;
1.28 + }
1.29 + distance += delta;
1.30 + }
1.31 + } while (meas.nextContour());
1.32 + return true;
1.33 +}
1.34 +
1.35 +///////////////////////////////////////////////////////////////////////////////
1.36 +
1.37 +SkPath1DPathEffect::SkPath1DPathEffect(const SkPath& path, SkScalar advance,
1.38 + SkScalar phase, Style style) : fPath(path)
1.39 +{
1.40 + if (advance <= 0 || path.isEmpty()) {
1.41 + SkDEBUGF(("SkPath1DPathEffect can't use advance <= 0\n"));
1.42 + fAdvance = 0; // signals we can't draw anything
1.43 + fInitialOffset = 0;
1.44 + fStyle = kStyleCount;
1.45 + } else {
1.46 + // cleanup their phase parameter, inverting it so that it becomes an
1.47 + // offset along the path (to match the interpretation in PostScript)
1.48 + if (phase < 0) {
1.49 + phase = -phase;
1.50 + if (phase > advance) {
1.51 + phase = SkScalarMod(phase, advance);
1.52 + }
1.53 + } else {
1.54 + if (phase > advance) {
1.55 + phase = SkScalarMod(phase, advance);
1.56 + }
1.57 + phase = advance - phase;
1.58 + }
1.59 + // now catch the edge case where phase == advance (within epsilon)
1.60 + if (phase >= advance) {
1.61 + phase = 0;
1.62 + }
1.63 + SkASSERT(phase >= 0);
1.64 +
1.65 + fAdvance = advance;
1.66 + fInitialOffset = phase;
1.67 +
1.68 + if ((unsigned)style >= kStyleCount) {
1.69 + SkDEBUGF(("SkPath1DPathEffect style enum out of range %d\n", style));
1.70 + }
1.71 + fStyle = style;
1.72 + }
1.73 +}
1.74 +
1.75 +bool SkPath1DPathEffect::filterPath(SkPath* dst, const SkPath& src,
1.76 + SkStrokeRec* rec, const SkRect* cullRect) const {
1.77 + if (fAdvance > 0) {
1.78 + rec->setFillStyle();
1.79 + return this->INHERITED::filterPath(dst, src, rec, cullRect);
1.80 + }
1.81 + return false;
1.82 +}
1.83 +
1.84 +static bool morphpoints(SkPoint dst[], const SkPoint src[], int count,
1.85 + SkPathMeasure& meas, SkScalar dist) {
1.86 + for (int i = 0; i < count; i++) {
1.87 + SkPoint pos;
1.88 + SkVector tangent;
1.89 +
1.90 + SkScalar sx = src[i].fX;
1.91 + SkScalar sy = src[i].fY;
1.92 +
1.93 + if (!meas.getPosTan(dist + sx, &pos, &tangent)) {
1.94 + return false;
1.95 + }
1.96 +
1.97 + SkMatrix matrix;
1.98 + SkPoint pt;
1.99 +
1.100 + pt.set(sx, sy);
1.101 + matrix.setSinCos(tangent.fY, tangent.fX, 0, 0);
1.102 + matrix.preTranslate(-sx, 0);
1.103 + matrix.postTranslate(pos.fX, pos.fY);
1.104 + matrix.mapPoints(&dst[i], &pt, 1);
1.105 + }
1.106 + return true;
1.107 +}
1.108 +
1.109 +/* TODO
1.110 +
1.111 +Need differentially more subdivisions when the follow-path is curvy. Not sure how to
1.112 +determine that, but we need it. I guess a cheap answer is let the caller tell us,
1.113 +but that seems like a cop-out. Another answer is to get Rob Johnson to figure it out.
1.114 +*/
1.115 +static void morphpath(SkPath* dst, const SkPath& src, SkPathMeasure& meas,
1.116 + SkScalar dist) {
1.117 + SkPath::Iter iter(src, false);
1.118 + SkPoint srcP[4], dstP[3];
1.119 + SkPath::Verb verb;
1.120 +
1.121 + while ((verb = iter.next(srcP)) != SkPath::kDone_Verb) {
1.122 + switch (verb) {
1.123 + case SkPath::kMove_Verb:
1.124 + if (morphpoints(dstP, srcP, 1, meas, dist)) {
1.125 + dst->moveTo(dstP[0]);
1.126 + }
1.127 + break;
1.128 + case SkPath::kLine_Verb:
1.129 + srcP[2] = srcP[1];
1.130 + srcP[1].set(SkScalarAve(srcP[0].fX, srcP[2].fX),
1.131 + SkScalarAve(srcP[0].fY, srcP[2].fY));
1.132 + // fall through to quad
1.133 + case SkPath::kQuad_Verb:
1.134 + if (morphpoints(dstP, &srcP[1], 2, meas, dist)) {
1.135 + dst->quadTo(dstP[0], dstP[1]);
1.136 + }
1.137 + break;
1.138 + case SkPath::kCubic_Verb:
1.139 + if (morphpoints(dstP, &srcP[1], 3, meas, dist)) {
1.140 + dst->cubicTo(dstP[0], dstP[1], dstP[2]);
1.141 + }
1.142 + break;
1.143 + case SkPath::kClose_Verb:
1.144 + dst->close();
1.145 + break;
1.146 + default:
1.147 + SkDEBUGFAIL("unknown verb");
1.148 + break;
1.149 + }
1.150 + }
1.151 +}
1.152 +
1.153 +SkPath1DPathEffect::SkPath1DPathEffect(SkReadBuffer& buffer) {
1.154 + fAdvance = buffer.readScalar();
1.155 + if (fAdvance > 0) {
1.156 + buffer.readPath(&fPath);
1.157 + fInitialOffset = buffer.readScalar();
1.158 + fStyle = (Style) buffer.readUInt();
1.159 + } else {
1.160 + SkDEBUGF(("SkPath1DPathEffect can't use advance <= 0\n"));
1.161 + // Make Coverity happy.
1.162 + fInitialOffset = 0;
1.163 + fStyle = kStyleCount;
1.164 + }
1.165 +}
1.166 +
1.167 +SkScalar SkPath1DPathEffect::begin(SkScalar contourLength) const {
1.168 + return fInitialOffset;
1.169 +}
1.170 +
1.171 +void SkPath1DPathEffect::flatten(SkWriteBuffer& buffer) const {
1.172 + this->INHERITED::flatten(buffer);
1.173 + buffer.writeScalar(fAdvance);
1.174 + if (fAdvance > 0) {
1.175 + buffer.writePath(fPath);
1.176 + buffer.writeScalar(fInitialOffset);
1.177 + buffer.writeUInt(fStyle);
1.178 + }
1.179 +}
1.180 +
1.181 +SkScalar SkPath1DPathEffect::next(SkPath* dst, SkScalar distance,
1.182 + SkPathMeasure& meas) const {
1.183 + switch (fStyle) {
1.184 + case kTranslate_Style: {
1.185 + SkPoint pos;
1.186 + if (meas.getPosTan(distance, &pos, NULL)) {
1.187 + dst->addPath(fPath, pos.fX, pos.fY);
1.188 + }
1.189 + } break;
1.190 + case kRotate_Style: {
1.191 + SkMatrix matrix;
1.192 + if (meas.getMatrix(distance, &matrix)) {
1.193 + dst->addPath(fPath, matrix);
1.194 + }
1.195 + } break;
1.196 + case kMorph_Style:
1.197 + morphpath(dst, fPath, meas, distance);
1.198 + break;
1.199 + default:
1.200 + SkDEBUGFAIL("unknown Style enum");
1.201 + break;
1.202 + }
1.203 + return fAdvance;
1.204 +}
