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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 "SkDashPathEffect.h"
#include "SkBuffer.h"
#include "SkPathMeasure.h"
static inline int is_even(int x) {
return (~x) << 31;
}
static SkScalar FindFirstInterval(const SkScalar intervals[], SkScalar phase,
int32_t* index) {
int i;
for (i = 0; phase > intervals[i]; i++) {
phase -= intervals[i];
}
*index = i;
return intervals[i] - phase;
}
SkDashPathEffect::SkDashPathEffect(const SkScalar intervals[], int count,
SkScalar phase, bool scaleToFit)
: fScaleToFit(scaleToFit) {
SkASSERT(intervals);
SkASSERT(count > 1 && SkAlign2(count) == count);
fIntervals = (SkScalar*)sk_malloc_throw(sizeof(SkScalar) * count);
fCount = count;
SkScalar len = 0;
for (int i = 0; i < count; i++) {
SkASSERT(intervals[i] >= 0);
fIntervals[i] = intervals[i];
len += intervals[i];
}
fIntervalLength = len;
// watch out for values that might make us go out of bounds
if ((len > 0) && SkScalarIsFinite(phase) && SkScalarIsFinite(len)) {
// Adjust phase to be between 0 and len, "flipping" phase if negative.
// e.g., if len is 100, then phase of -20 (or -120) is equivalent to 80
if (phase < 0) {
phase = -phase;
if (phase > len) {
phase = SkScalarMod(phase, len);
}
phase = len - phase;
// Due to finite precision, it's possible that phase == len,
// even after the subtract (if len >>> phase), so fix that here.
// This fixes http://crbug.com/124652 .
SkASSERT(phase <= len);
if (phase == len) {
phase = 0;
}
} else if (phase >= len) {
phase = SkScalarMod(phase, len);
}
SkASSERT(phase >= 0 && phase < len);
fInitialDashLength = FindFirstInterval(intervals, phase, &fInitialDashIndex);
SkASSERT(fInitialDashLength >= 0);
SkASSERT(fInitialDashIndex >= 0 && fInitialDashIndex < fCount);
} else {
fInitialDashLength = -1; // signal bad dash intervals
}
}
SkDashPathEffect::~SkDashPathEffect() {
sk_free(fIntervals);
}
bool SkDashPathEffect::filterPath(SkPath* dst, const SkPath& src,
SkStrokeRec* rec) {
// we do nothing if the src wants to be filled, or if our dashlength is 0
if (rec->isFillStyle() || fInitialDashLength < 0) {
return false;
}
SkPathMeasure meas(src, false);
const SkScalar* intervals = fIntervals;
do {
bool skipFirstSegment = meas.isClosed();
bool addedSegment = false;
SkScalar length = meas.getLength();
int index = fInitialDashIndex;
SkScalar scale = SK_Scalar1;
if (fScaleToFit) {
if (fIntervalLength >= length) {
scale = SkScalarDiv(length, fIntervalLength);
} else {
SkScalar div = SkScalarDiv(length, fIntervalLength);
int n = SkScalarFloor(div);
scale = SkScalarDiv(length, n * fIntervalLength);
}
}
SkScalar distance = 0;
SkScalar dlen = SkScalarMul(fInitialDashLength, scale);
while (distance < length) {
SkASSERT(dlen >= 0);
addedSegment = false;
if (is_even(index) && dlen > 0 && !skipFirstSegment) {
addedSegment = true;
meas.getSegment(distance, distance + dlen, dst, true);
}
distance += dlen;
// clear this so we only respect it the first time around
skipFirstSegment = false;
// wrap around our intervals array if necessary
index += 1;
SkASSERT(index <= fCount);
if (index == fCount) {
index = 0;
}
// fetch our next dlen
dlen = SkScalarMul(intervals[index], scale);
}
// extend if we ended on a segment and we need to join up with the (skipped) initial segment
if (meas.isClosed() && is_even(fInitialDashIndex) &&
fInitialDashLength > 0) {
meas.getSegment(0, SkScalarMul(fInitialDashLength, scale), dst, !addedSegment);
}
} while (meas.nextContour());
return true;
}
SkFlattenable::Factory SkDashPathEffect::getFactory() {
return fInitialDashLength < 0 ? NULL : CreateProc;
}
void SkDashPathEffect::flatten(SkFlattenableWriteBuffer& buffer) const {
SkASSERT(fInitialDashLength >= 0);
this->INHERITED::flatten(buffer);
buffer.write32(fCount);
buffer.write32(fInitialDashIndex);
buffer.writeScalar(fInitialDashLength);
buffer.writeScalar(fIntervalLength);
buffer.write32(fScaleToFit);
buffer.writeMul4(fIntervals, fCount * sizeof(fIntervals[0]));
}
SkFlattenable* SkDashPathEffect::CreateProc(SkFlattenableReadBuffer& buffer) {
return SkNEW_ARGS(SkDashPathEffect, (buffer));
}
SkDashPathEffect::SkDashPathEffect(SkFlattenableReadBuffer& buffer) {
fCount = buffer.readS32();
fInitialDashIndex = buffer.readS32();
fInitialDashLength = buffer.readScalar();
fIntervalLength = buffer.readScalar();
fScaleToFit = (buffer.readS32() != 0);
fIntervals = (SkScalar*)sk_malloc_throw(sizeof(SkScalar) * fCount);
buffer.read(fIntervals, fCount * sizeof(fIntervals[0]));
}
///////////////////////////////////////////////////////////////////////////////
SK_DEFINE_FLATTENABLE_REGISTRAR(SkDashPathEffect)
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