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/*
* Copyright 2006 The Android Open Source Project
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "Sk1DPathEffect.h"
#include "SkReadBuffer.h"
#include "SkWriteBuffer.h"
#include "SkPathMeasure.h"
bool Sk1DPathEffect::filterPath(SkPath* dst, const SkPath& src,
SkStrokeRec*, const SkRect*) const {
SkPathMeasure meas(src, false);
do {
SkScalar length = meas.getLength();
SkScalar distance = this->begin(length);
while (distance < length) {
SkScalar delta = this->next(dst, distance, meas);
if (delta <= 0) {
break;
}
distance += delta;
}
} while (meas.nextContour());
return true;
}
///////////////////////////////////////////////////////////////////////////////
SkPath1DPathEffect::SkPath1DPathEffect(const SkPath& path, SkScalar advance,
SkScalar phase, Style style) : fPath(path)
{
if (advance <= 0 || path.isEmpty()) {
SkDEBUGF(("SkPath1DPathEffect can't use advance <= 0\n"));
fAdvance = 0; // signals we can't draw anything
fInitialOffset = 0;
fStyle = kStyleCount;
} else {
// cleanup their phase parameter, inverting it so that it becomes an
// offset along the path (to match the interpretation in PostScript)
if (phase < 0) {
phase = -phase;
if (phase > advance) {
phase = SkScalarMod(phase, advance);
}
} else {
if (phase > advance) {
phase = SkScalarMod(phase, advance);
}
phase = advance - phase;
}
// now catch the edge case where phase == advance (within epsilon)
if (phase >= advance) {
phase = 0;
}
SkASSERT(phase >= 0);
fAdvance = advance;
fInitialOffset = phase;
if ((unsigned)style >= kStyleCount) {
SkDEBUGF(("SkPath1DPathEffect style enum out of range %d\n", style));
}
fStyle = style;
}
}
bool SkPath1DPathEffect::filterPath(SkPath* dst, const SkPath& src,
SkStrokeRec* rec, const SkRect* cullRect) const {
if (fAdvance > 0) {
rec->setFillStyle();
return this->INHERITED::filterPath(dst, src, rec, cullRect);
}
return false;
}
static bool morphpoints(SkPoint dst[], const SkPoint src[], int count,
SkPathMeasure& meas, SkScalar dist) {
for (int i = 0; i < count; i++) {
SkPoint pos;
SkVector tangent;
SkScalar sx = src[i].fX;
SkScalar sy = src[i].fY;
if (!meas.getPosTan(dist + sx, &pos, &tangent)) {
return false;
}
SkMatrix matrix;
SkPoint pt;
pt.set(sx, sy);
matrix.setSinCos(tangent.fY, tangent.fX, 0, 0);
matrix.preTranslate(-sx, 0);
matrix.postTranslate(pos.fX, pos.fY);
matrix.mapPoints(&dst[i], &pt, 1);
}
return true;
}
/* TODO
Need differentially more subdivisions when the follow-path is curvy. Not sure how to
determine that, but we need it. I guess a cheap answer is let the caller tell us,
but that seems like a cop-out. Another answer is to get Rob Johnson to figure it out.
*/
static void morphpath(SkPath* dst, const SkPath& src, SkPathMeasure& meas,
SkScalar dist) {
SkPath::Iter iter(src, false);
SkPoint srcP[4], dstP[3];
SkPath::Verb verb;
while ((verb = iter.next(srcP)) != SkPath::kDone_Verb) {
switch (verb) {
case SkPath::kMove_Verb:
if (morphpoints(dstP, srcP, 1, meas, dist)) {
dst->moveTo(dstP[0]);
}
break;
case SkPath::kLine_Verb:
srcP[2] = srcP[1];
srcP[1].set(SkScalarAve(srcP[0].fX, srcP[2].fX),
SkScalarAve(srcP[0].fY, srcP[2].fY));
// fall through to quad
case SkPath::kQuad_Verb:
if (morphpoints(dstP, &srcP[1], 2, meas, dist)) {
dst->quadTo(dstP[0], dstP[1]);
}
break;
case SkPath::kCubic_Verb:
if (morphpoints(dstP, &srcP[1], 3, meas, dist)) {
dst->cubicTo(dstP[0], dstP[1], dstP[2]);
}
break;
case SkPath::kClose_Verb:
dst->close();
break;
default:
SkDEBUGFAIL("unknown verb");
break;
}
}
}
SkScalar SkPath1DPathEffect::begin(SkScalar contourLength) const {
return fInitialOffset;
}
SkFlattenable* SkPath1DPathEffect::CreateProc(SkReadBuffer& buffer) {
SkScalar advance = buffer.readScalar();
if (advance > 0) {
SkPath path;
buffer.readPath(&path);
SkScalar phase = buffer.readScalar();
Style style = (Style)buffer.readUInt();
return SkPath1DPathEffect::Create(path, advance, phase, style);
}
return NULL;
}
void SkPath1DPathEffect::flatten(SkWriteBuffer& buffer) const {
buffer.writeScalar(fAdvance);
if (fAdvance > 0) {
buffer.writePath(fPath);
buffer.writeScalar(fInitialOffset);
buffer.writeUInt(fStyle);
}
}
SkScalar SkPath1DPathEffect::next(SkPath* dst, SkScalar distance,
SkPathMeasure& meas) const {
switch (fStyle) {
case kTranslate_Style: {
SkPoint pos;
if (meas.getPosTan(distance, &pos, NULL)) {
dst->addPath(fPath, pos.fX, pos.fY);
}
} break;
case kRotate_Style: {
SkMatrix matrix;
if (meas.getMatrix(distance, &matrix)) {
dst->addPath(fPath, matrix);
}
} break;
case kMorph_Style:
morphpath(dst, fPath, meas, distance);
break;
default:
SkDEBUGFAIL("unknown Style enum");
break;
}
return fAdvance;
}
#ifndef SK_IGNORE_TO_STRING
void SkPath1DPathEffect::toString(SkString* str) const {
str->appendf("SkPath1DPathEffect: (");
// TODO: add path and style
str->appendf("advance: %.2f phase %.2f", fAdvance, fInitialOffset);
str->appendf(")");
}
#endif
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