/*
* 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() {
fOperand = false;
fXorMask[0] = fXorMask[1] = (fPath->getFillType() & 1) ? kEvenOdd_PathOpsMask
: kWinding_PathOpsMask;
fUnparseable = false;
fSecondHalf = preFetch();
}
// 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;
}
}
static bool can_add_curve(SkPath::Verb verb, SkPoint* curve) {
if (SkPath::kMove_Verb == verb) {
return false;
}
for (int index = 0; index <= SkPathOpsVerbToPoints(verb); ++index) {
force_small_to_zero(&curve[index]);
}
return SkPath::kLine_Verb != verb || !SkDPoint::ApproximatelyEqual(curve[0], curve[1]);
}
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();
}
bool SkOpEdgeBuilder::finish() {
fOperand = false;
if (fUnparseable || !walk()) {
return false;
}
complete();
SkOpContour* contour = fContourBuilder.contour();
if (contour && !contour->count()) {
fContoursHead->remove(contour);
}
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 {
int verbCount = fPathVerbs.count();
int ptsCount = fPathPts.count();
if (SkPath::kLine_Verb == fPathVerbs[verbCount - 1]
&& fPathPts[ptsCount - 2] == curveStart) {
fPathVerbs.pop();
fPathPts.pop();
} else {
fPathPts[ptsCount - 1] = curveStart;
}
}
*fPathVerbs.append() = SkPath::kClose_Verb;
}
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() = curve[0] = 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::Quad(curve, pts);
if (SkPath::kQuad_Verb == verb && 1 != iter.conicWeight()) {
verb = SkPath::kConic_Verb;
} else 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();
SkScalar* weightPtr = fWeights.begin();
SkPath::Verb verb;
SkOpContour* contour = fContourBuilder.contour();
int moveToPtrBump = 0;
while ((verb = (SkPath::Verb) *verbPtr) != SkPath::kDone_Verb) {
if (verbPtr == endOfFirstHalf) {
fOperand = true;
}
verbPtr++;
switch (verb) {
case SkPath::kMove_Verb:
if (contour && contour->count()) {
if (fAllowOpenContours) {
complete();
} else if (!close()) {
return false;
}
}
if (!contour) {
fContourBuilder.setContour(contour = fContoursHead->appendContour());
}
contour->init(fGlobalState, fOperand,
fXorMask[fOperand] == kEvenOdd_PathOpsMask);
pointsPtr += moveToPtrBump;
moveToPtrBump = 1;
continue;
case SkPath::kLine_Verb:
fContourBuilder.addLine(pointsPtr);
break;
case SkPath::kQuad_Verb:
{
SkVector v1 = pointsPtr[1] - pointsPtr[0];
SkVector v2 = pointsPtr[2] - pointsPtr[1];
if (v1.dot(v2) < 0) {
SkPoint pair[5];
if (SkChopQuadAtMaxCurvature(pointsPtr, pair) == 1) {
goto addOneQuad;
}
if (!SkScalarsAreFinite(&pair[0].fX, SK_ARRAY_COUNT(pair) * 2)) {
return false;
}
for (unsigned index = 0; index < SK_ARRAY_COUNT(pair); ++index) {
force_small_to_zero(&pair[index]);
}
SkPoint cStorage[2][2];
SkPath::Verb v1 = SkReduceOrder::Quad(&pair[0], cStorage[0]);
SkPath::Verb v2 = SkReduceOrder::Quad(&pair[2], cStorage[1]);
SkPoint* curve1 = v1 != SkPath::kLine_Verb ? &pair[0] : cStorage[0];
SkPoint* curve2 = v2 != SkPath::kLine_Verb ? &pair[2] : cStorage[1];
if (can_add_curve(v1, curve1) && can_add_curve(v2, curve2)) {
fContourBuilder.addCurve(v1, curve1);
fContourBuilder.addCurve(v2, curve2);
break;
}
}
}
addOneQuad:
fContourBuilder.addQuad(pointsPtr);
break;
case SkPath::kConic_Verb: {
SkVector v1 = pointsPtr[1] - pointsPtr[0];
SkVector v2 = pointsPtr[2] - pointsPtr[1];
SkScalar weight = *weightPtr++;
if (v1.dot(v2) < 0) {
// FIXME: max curvature for conics hasn't been implemented; use placeholder
SkScalar maxCurvature = SkFindQuadMaxCurvature(pointsPtr);
if (0 < maxCurvature && maxCurvature < 1) {
SkConic conic(pointsPtr, weight);
SkConic pair[2];
if (!conic.chopAt(maxCurvature, pair)) {
// if result can't be computed, use original
fContourBuilder.addConic(pointsPtr, weight);
break;
}
SkPoint cStorage[2][3];
SkPath::Verb v1 = SkReduceOrder::Conic(pair[0], cStorage[0]);
SkPath::Verb v2 = SkReduceOrder::Conic(pair[1], cStorage[1]);
SkPoint* curve1 = v1 != SkPath::kLine_Verb ? pair[0].fPts : cStorage[0];
SkPoint* curve2 = v2 != SkPath::kLine_Verb ? pair[1].fPts : cStorage[1];
if (can_add_curve(v1, curve1) && can_add_curve(v2, curve2)) {
fContourBuilder.addCurve(v1, curve1, pair[0].fW);
fContourBuilder.addCurve(v2, curve2, pair[1].fW);
break;
}
}
}
fContourBuilder.addConic(pointsPtr, weight);
} 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[3];
int breaks = SkDCubic::ComplexBreak(pointsPtr, splitT);
if (!breaks) {
fContourBuilder.addCubic(pointsPtr);
break;
}
SkASSERT(breaks <= (int) SK_ARRAY_COUNT(splitT));
struct Splitsville {
double fT[2];
SkPoint fPts[4];
SkPoint fReduced[4];
SkPath::Verb fVerb;
bool fCanAdd;
} splits[4];
SkASSERT(SK_ARRAY_COUNT(splits) == SK_ARRAY_COUNT(splitT) + 1);
SkTQSort(splitT, &splitT[breaks - 1]);
for (int index = 0; index <= breaks; ++index) {
Splitsville* split = &splits[index];
split->fT[0] = index ? splitT[index - 1] : 0;
split->fT[1] = index < breaks ? splitT[index] : 1;
SkDCubic part = SkDCubic::SubDivide(pointsPtr, split->fT[0], split->fT[1]);
if (!part.toFloatPoints(split->fPts)) {
return false;
}
split->fVerb = SkReduceOrder::Cubic(split->fPts, split->fReduced);
SkPoint* curve = SkPath::kCubic_Verb == verb
? split->fPts : split->fReduced;
split->fCanAdd = can_add_curve(split->fVerb, curve);
}
for (int index = 0; index <= breaks; ++index) {
Splitsville* split = &splits[index];
if (!split->fCanAdd) {
continue;
}
int prior = index;
while (prior > 0 && !splits[prior - 1].fCanAdd) {
--prior;
}
if (prior < index) {
split->fT[0] = splits[prior].fT[0];
split->fPts[0] = splits[prior].fPts[0];
}
int next = index;
int breakLimit = SkTMin(breaks, (int) SK_ARRAY_COUNT(splits) - 1);
while (next < breakLimit && !splits[next + 1].fCanAdd) {
++next;
}
if (next > index) {
split->fT[1] = splits[next].fT[1];
split->fPts[3] = splits[next].fPts[3];
}
if (prior < index || next > index) {
split->fVerb = SkReduceOrder::Cubic(split->fPts, split->fReduced);
}
SkPoint* curve = SkPath::kCubic_Verb == split->fVerb
? split->fPts : split->fReduced;
if (!can_add_curve(split->fVerb, curve)) {
return false;
}
fContourBuilder.addCurve(split->fVerb, curve);
}
}
break;
case SkPath::kClose_Verb:
SkASSERT(contour);
if (!close()) {
return false;
}
contour = nullptr;
continue;
default:
SkDEBUGFAIL("bad verb");
return false;
}
SkASSERT(contour);
if (contour->count()) {
contour->debugValidate();
}
pointsPtr += SkPathOpsVerbToPoints(verb);
}
fContourBuilder.flush();
if (contour && contour->count() &&!fAllowOpenContours && !close()) {
return false;
}
return true;
}