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/*
* Copyright 2012 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkGeometry.h"
#include "SkOpEdgeBuilder.h"
#include "SkReduceOrder.h"
void SkOpEdgeBuilder::init() {
fCurrentContour = fContoursHead;
fOperand = false;
fXorMask[0] = fXorMask[1] = (fPath->getFillType() & 1) ? kEvenOdd_PathOpsMask
: kWinding_PathOpsMask;
fUnparseable = false;
fSecondHalf = preFetch();
}
void SkOpEdgeBuilder::addOperand(const SkPath& path) {
SkASSERT(fPathVerbs.count() > 0 && fPathVerbs.end()[-1] == SkPath::kDone_Verb);
fPathVerbs.pop();
fPath = &path;
fXorMask[1] = (fPath->getFillType() & 1) ? kEvenOdd_PathOpsMask
: kWinding_PathOpsMask;
preFetch();
}
int SkOpEdgeBuilder::count() const {
SkOpContour* contour = fContoursHead;
int count = 0;
while (contour) {
count += contour->count() > 0;
contour = contour->next();
}
return count;
}
bool SkOpEdgeBuilder::finish() {
fOperand = false;
if (fUnparseable || !walk()) {
return false;
}
complete();
if (fCurrentContour && !fCurrentContour->count()) {
fContoursHead->remove(fCurrentContour);
}
return true;
}
void SkOpEdgeBuilder::closeContour(const SkPoint& curveEnd, const SkPoint& curveStart) {
if (!SkDPoint::ApproximatelyEqual(curveEnd, curveStart)) {
*fPathVerbs.append() = SkPath::kLine_Verb;
*fPathPts.append() = curveStart;
} else {
fPathPts[fPathPts.count() - 1] = curveStart;
}
*fPathVerbs.append() = SkPath::kClose_Verb;
}
// very tiny points cause numerical instability : don't allow them
static void force_small_to_zero(SkPoint* pt) {
if (SkScalarAbs(pt->fX) < FLT_EPSILON_ORDERABLE_ERR) {
pt->fX = 0;
}
if (SkScalarAbs(pt->fY) < FLT_EPSILON_ORDERABLE_ERR) {
pt->fY = 0;
}
}
int SkOpEdgeBuilder::preFetch() {
if (!fPath->isFinite()) {
fUnparseable = true;
return 0;
}
SkPath::RawIter iter(*fPath);
SkPoint curveStart;
SkPoint curve[4];
SkPoint pts[4];
SkPath::Verb verb;
bool lastCurve = false;
do {
verb = iter.next(pts);
switch (verb) {
case SkPath::kMove_Verb:
if (!fAllowOpenContours && lastCurve) {
closeContour(curve[0], curveStart);
}
*fPathVerbs.append() = verb;
force_small_to_zero(&pts[0]);
*fPathPts.append() = pts[0];
curveStart = curve[0] = pts[0];
lastCurve = false;
continue;
case SkPath::kLine_Verb:
force_small_to_zero(&pts[1]);
if (SkDPoint::ApproximatelyEqual(curve[0], pts[1])) {
uint8_t lastVerb = fPathVerbs.top();
if (lastVerb != SkPath::kLine_Verb && lastVerb != SkPath::kMove_Verb) {
fPathPts.top() = pts[1];
}
continue; // skip degenerate points
}
break;
case SkPath::kQuad_Verb:
force_small_to_zero(&pts[1]);
force_small_to_zero(&pts[2]);
curve[1] = pts[1];
curve[2] = pts[2];
verb = SkReduceOrder::Quad(curve, pts);
if (verb == SkPath::kMove_Verb) {
continue; // skip degenerate points
}
break;
case SkPath::kConic_Verb:
force_small_to_zero(&pts[1]);
force_small_to_zero(&pts[2]);
curve[1] = pts[1];
curve[2] = pts[2];
verb = SkReduceOrder::Conic(curve, iter.conicWeight(), pts);
if (verb == SkPath::kMove_Verb) {
continue; // skip degenerate points
}
break;
case SkPath::kCubic_Verb:
force_small_to_zero(&pts[1]);
force_small_to_zero(&pts[2]);
force_small_to_zero(&pts[3]);
curve[1] = pts[1];
curve[2] = pts[2];
curve[3] = pts[3];
verb = SkReduceOrder::Cubic(curve, pts);
if (verb == SkPath::kMove_Verb) {
continue; // skip degenerate points
}
break;
case SkPath::kClose_Verb:
closeContour(curve[0], curveStart);
lastCurve = false;
continue;
case SkPath::kDone_Verb:
continue;
}
*fPathVerbs.append() = verb;
int ptCount = SkPathOpsVerbToPoints(verb);
fPathPts.append(ptCount, &pts[1]);
if (verb == SkPath::kConic_Verb) {
*fWeights.append() = iter.conicWeight();
}
curve[0] = pts[ptCount];
lastCurve = true;
} while (verb != SkPath::kDone_Verb);
if (!fAllowOpenContours && lastCurve) {
closeContour(curve[0], curveStart);
}
*fPathVerbs.append() = SkPath::kDone_Verb;
return fPathVerbs.count() - 1;
}
bool SkOpEdgeBuilder::close() {
complete();
return true;
}
bool SkOpEdgeBuilder::walk() {
uint8_t* verbPtr = fPathVerbs.begin();
uint8_t* endOfFirstHalf = &verbPtr[fSecondHalf];
SkPoint* pointsPtr = fPathPts.begin() - 1;
SkScalar* weightPtr = fWeights.begin();
SkPath::Verb verb;
while ((verb = (SkPath::Verb) *verbPtr) != SkPath::kDone_Verb) {
if (verbPtr == endOfFirstHalf) {
fOperand = true;
}
verbPtr++;
switch (verb) {
case SkPath::kMove_Verb:
if (fCurrentContour && fCurrentContour->count()) {
if (fAllowOpenContours) {
complete();
} else if (!close()) {
return false;
}
}
if (!fCurrentContour) {
fCurrentContour = fContoursHead->appendContour();
}
fCurrentContour->init(fGlobalState, fOperand,
fXorMask[fOperand] == kEvenOdd_PathOpsMask);
pointsPtr += 1;
continue;
case SkPath::kLine_Verb:
fCurrentContour->addLine(pointsPtr);
break;
case SkPath::kQuad_Verb:
fCurrentContour->addQuad(pointsPtr);
break;
case SkPath::kConic_Verb:
fCurrentContour->addConic(pointsPtr, *weightPtr++);
break;
case SkPath::kCubic_Verb: {
// Split complex cubics (such as self-intersecting curves or
// ones with difficult curvature) in two before proceeding.
// This can be required for intersection to succeed.
SkScalar splitT;
if (SkDCubic::ComplexBreak(pointsPtr, &splitT)) {
SkPoint cubicPair[7];
SkChopCubicAt(pointsPtr, cubicPair, splitT);
if (!SkScalarsAreFinite(&cubicPair[0].fX, SK_ARRAY_COUNT(cubicPair) * 2)) {
return false;
}
SkPoint cStorage[2][4];
SkPath::Verb v1 = SkReduceOrder::Cubic(&cubicPair[0], cStorage[0]);
SkPath::Verb v2 = SkReduceOrder::Cubic(&cubicPair[3], cStorage[1]);
if (v1 != SkPath::kMove_Verb && v2 != SkPath::kMove_Verb) {
SkPoint* curve1 = v1 == SkPath::kCubic_Verb ? &cubicPair[0] : cStorage[0];
SkPoint* curve2 = v2 == SkPath::kCubic_Verb ? &cubicPair[3] : cStorage[1];
for (int index = 0; index < SkPathOpsVerbToPoints(v1); ++index) {
force_small_to_zero(&curve1[index]);
}
for (int index = 0; index < SkPathOpsVerbToPoints(v2); ++index) {
force_small_to_zero(&curve2[index]);
}
fCurrentContour->addCurve(v1, curve1);
fCurrentContour->addCurve(v2, curve2);
} else {
fCurrentContour->addCubic(pointsPtr);
}
} else {
fCurrentContour->addCubic(pointsPtr);
}
} break;
case SkPath::kClose_Verb:
SkASSERT(fCurrentContour);
if (!close()) {
return false;
}
continue;
default:
SkDEBUGFAIL("bad verb");
return false;
}
SkASSERT(fCurrentContour);
fCurrentContour->debugValidate();
pointsPtr += SkPathOpsVerbToPoints(verb);
}
if (fCurrentContour && fCurrentContour->count() &&!fAllowOpenContours && !close()) {
return false;
}
return true;
}
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