/*
* 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 "SkAddIntersections.h"
#include "SkOpCoincidence.h"
#include "SkOpEdgeBuilder.h"
#include "SkPathOpsCommon.h"
#include "SkPathWriter.h"
#include <utility>
static bool findChaseOp(SkTDArray<SkOpSpanBase*>& chase, SkOpSpanBase** startPtr,
SkOpSpanBase** endPtr, SkOpSegment** result) {
while (chase.count()) {
SkOpSpanBase* span;
chase.pop(&span);
// OPTIMIZE: prev makes this compatible with old code -- but is it necessary?
*startPtr = span->ptT()->prev()->span();
SkOpSegment* segment = (*startPtr)->segment();
bool done = true;
*endPtr = nullptr;
if (SkOpAngle* last = segment->activeAngle(*startPtr, startPtr, endPtr, &done)) {
*startPtr = last->start();
*endPtr = last->end();
#if TRY_ROTATE
*chase.insert(0) = span;
#else
*chase.append() = span;
#endif
*result = last->segment();
return true;
}
if (done) {
continue;
}
int winding;
bool sortable;
const SkOpAngle* angle = AngleWinding(*startPtr, *endPtr, &winding, &sortable);
if (!angle) {
*result = nullptr;
return true;
}
if (winding == SK_MinS32) {
continue;
}
int sumMiWinding, sumSuWinding;
if (sortable) {
segment = angle->segment();
sumMiWinding = segment->updateWindingReverse(angle);
if (sumMiWinding == SK_MinS32) {
SkASSERT(segment->globalState()->debugSkipAssert());
*result = nullptr;
return true;
}
sumSuWinding = segment->updateOppWindingReverse(angle);
if (sumSuWinding == SK_MinS32) {
SkASSERT(segment->globalState()->debugSkipAssert());
*result = nullptr;
return true;
}
if (segment->operand()) {
using std::swap;
swap(sumMiWinding, sumSuWinding);
}
}
SkOpSegment* first = nullptr;
const SkOpAngle* firstAngle = angle;
while ((angle = angle->next()) != firstAngle) {
segment = angle->segment();
SkOpSpanBase* start = angle->start();
SkOpSpanBase* end = angle->end();
int maxWinding = 0, sumWinding = 0, oppMaxWinding = 0, oppSumWinding = 0;
if (sortable) {
segment->setUpWindings(start, end, &sumMiWinding, &sumSuWinding,
&maxWinding, &sumWinding, &oppMaxWinding, &oppSumWinding);
}
if (!segment->done(angle)) {
if (!first && (sortable || start->starter(end)->windSum() != SK_MinS32)) {
first = segment;
*startPtr = start;
*endPtr = end;
}
// OPTIMIZATION: should this also add to the chase?
if (sortable) {
if (!segment->markAngle(maxWinding, sumWinding, oppMaxWinding,
oppSumWinding, angle, nullptr)) {
return false;
}
}
}
}
if (first) {
#if TRY_ROTATE
*chase.insert(0) = span;
#else
*chase.append() = span;
#endif
*result = first;
return true;
}
}
*result = nullptr;
return true;
}
static bool bridgeOp(SkOpContourHead* contourList, const SkPathOp op,
const int xorMask, const int xorOpMask, SkPathWriter* writer) {
bool unsortable = false;
bool lastSimple = false;
bool simple = false;
do {
SkOpSpan* span = FindSortableTop(contourList);
if (!span) {
break;
}
SkOpSegment* current = span->segment();
SkOpSpanBase* start = span->next();
SkOpSpanBase* end = span;
SkTDArray<SkOpSpanBase*> chase;
do {
if (current->activeOp(start, end, xorMask, xorOpMask, op)) {
do {
if (!unsortable && current->done()) {
break;
}
SkASSERT(unsortable || !current->done());
SkOpSpanBase* nextStart = start;
SkOpSpanBase* nextEnd = end;
lastSimple = simple;
SkOpSegment* next = current->findNextOp(&chase, &nextStart, &nextEnd,
&unsortable, &simple, op, xorMask, xorOpMask);
if (!next) {
if (!unsortable && writer->hasMove()
&& current->verb() != SkPath::kLine_Verb
&& !writer->isClosed()) {
if (!current->addCurveTo(start, end, writer)) {
return false;
}
if (!writer->isClosed()) {
SkPathOpsDebug::ShowActiveSpans(contourList);
}
} else if (lastSimple) {
if (!current->addCurveTo(start, end, writer)) {
return false;
}
}
break;
}
#if DEBUG_FLOW
SkDebugf("%s current id=%d from=(%1.9g,%1.9g) to=(%1.9g,%1.9g)\n", __FUNCTION__,
current->debugID(), start->pt().fX, start->pt().fY,
end->pt().fX, end->pt().fY);
#endif
if (!current->addCurveTo(start, end, writer)) {
return false;
}
current = next;
start = nextStart;
end = nextEnd;
} while (!writer->isClosed() && (!unsortable || !start->starter(end)->done()));
if (current->activeWinding(start, end) && !writer->isClosed()) {
SkOpSpan* spanStart = start->starter(end);
if (!spanStart->done()) {
if (!current->addCurveTo(start, end, writer)) {
return false;
}
current->markDone(spanStart);
}
}
writer->finishContour();
} else {
SkOpSpanBase* last;
if (!current->markAndChaseDone(start, end, &last)) {
return false;
}
if (last && !last->chased()) {
last->setChased(true);
SkASSERT(!SkPathOpsDebug::ChaseContains(chase, last));
*chase.append() = last;
#if DEBUG_WINDING
SkDebugf("%s chase.append id=%d", __FUNCTION__, last->segment()->debugID());
if (!last->final()) {
SkDebugf(" windSum=%d", last->upCast()->windSum());
}
SkDebugf("\n");
#endif
}
}
if (!findChaseOp(chase, &start, &end, ¤t)) {
return false;
}
SkPathOpsDebug::ShowActiveSpans(contourList);
if (!current) {
break;
}
} while (true);
} while (true);
return true;
}
// diagram of why this simplifcation is possible is here:
// https://skia.org/dev/present/pathops link at bottom of the page
// https://drive.google.com/file/d/0BwoLUwz9PYkHLWpsaXd0UDdaN00/view?usp=sharing
static const SkPathOp gOpInverse[kReverseDifference_SkPathOp + 1][2][2] = {
// inside minuend outside minuend
// inside subtrahend outside subtrahend inside subtrahend outside subtrahend
{{ kDifference_SkPathOp, kIntersect_SkPathOp }, { kUnion_SkPathOp, kReverseDifference_SkPathOp }},
{{ kIntersect_SkPathOp, kDifference_SkPathOp }, { kReverseDifference_SkPathOp, kUnion_SkPathOp }},
{{ kUnion_SkPathOp, kReverseDifference_SkPathOp }, { kDifference_SkPathOp, kIntersect_SkPathOp }},
{{ kXOR_SkPathOp, kXOR_SkPathOp }, { kXOR_SkPathOp, kXOR_SkPathOp }},
{{ kReverseDifference_SkPathOp, kUnion_SkPathOp }, { kIntersect_SkPathOp, kDifference_SkPathOp }},
};
static const bool gOutInverse[kReverseDifference_SkPathOp + 1][2][2] = {
{{ false, false }, { true, false }}, // diff
{{ false, false }, { false, true }}, // sect
{{ false, true }, { true, true }}, // union
{{ false, true }, { true, false }}, // xor
{{ false, true }, { false, false }}, // rev diff
};
#if DEBUG_T_SECT_LOOP_COUNT
#include "SkMutex.h"
SK_DECLARE_STATIC_MUTEX(debugWorstLoop);
SkOpGlobalState debugWorstState(nullptr, nullptr SkDEBUGPARAMS(false) SkDEBUGPARAMS(nullptr));
void ReportPathOpsDebugging() {
debugWorstState.debugLoopReport();
}
extern void (*gVerboseFinalize)();
#endif
bool OpDebug(const SkPath& one, const SkPath& two, SkPathOp op, SkPath* result
SkDEBUGPARAMS(bool skipAssert) SkDEBUGPARAMS(const char* testName)) {
#if DEBUG_DUMP_VERIFY
#ifndef SK_DEBUG
const char* testName = "release";
#endif
if (SkPathOpsDebug::gDumpOp) {
SkPathOpsDebug::DumpOp(one, two, op, testName);
}
#endif
op = gOpInverse[op][one.isInverseFillType()][two.isInverseFillType()];
bool inverseFill = gOutInverse[op][one.isInverseFillType()][two.isInverseFillType()];
SkPath::FillType fillType = inverseFill ? SkPath::kInverseEvenOdd_FillType :
SkPath::kEvenOdd_FillType;
SkRect rect1, rect2;
if (kIntersect_SkPathOp == op && one.isRect(&rect1) && two.isRect(&rect2)) {
result->reset();
result->setFillType(fillType);
if (rect1.intersect(rect2)) {
result->addRect(rect1);
}
return true;
}
if (one.isEmpty() || two.isEmpty()) {
SkPath work;
switch (op) {
case kIntersect_SkPathOp:
break;
case kUnion_SkPathOp:
case kXOR_SkPathOp:
work = one.isEmpty() ? two : one;
break;
case kDifference_SkPathOp:
if (!one.isEmpty()) {
work = one;
}
break;
case kReverseDifference_SkPathOp:
if (!two.isEmpty()) {
work = two;
}
break;
default:
SkASSERT(0); // unhandled case
}
if (inverseFill != work.isInverseFillType()) {
work.toggleInverseFillType();
}
return Simplify(work, result);
}
SkSTArenaAlloc<4096> allocator; // FIXME: add a constant expression here, tune
SkOpContour contour;
SkOpContourHead* contourList = static_cast<SkOpContourHead*>(&contour);
SkOpGlobalState globalState(contourList, &allocator
SkDEBUGPARAMS(skipAssert) SkDEBUGPARAMS(testName));
SkOpCoincidence coincidence(&globalState);
const SkPath* minuend = &one;
const SkPath* subtrahend = &two;
if (op == kReverseDifference_SkPathOp) {
using std::swap;
swap(minuend, subtrahend);
op = kDifference_SkPathOp;
}
#if DEBUG_SORT
SkPathOpsDebug::gSortCount = SkPathOpsDebug::gSortCountDefault;
#endif
// turn path into list of segments
SkOpEdgeBuilder builder(*minuend, contourList, &globalState);
if (builder.unparseable()) {
return false;
}
const int xorMask = builder.xorMask();
builder.addOperand(*subtrahend);
if (!builder.finish()) {
return false;
}
#if DEBUG_DUMP_SEGMENTS
contourList->dumpSegments("seg", op);
#endif
const int xorOpMask = builder.xorMask();
if (!SortContourList(&contourList, xorMask == kEvenOdd_PathOpsMask,
xorOpMask == kEvenOdd_PathOpsMask)) {
result->reset();
result->setFillType(fillType);
return true;
}
// find all intersections between segments
SkOpContour* current = contourList;
do {
SkOpContour* next = current;
while (AddIntersectTs(current, next, &coincidence)
&& (next = next->next()))
;
} while ((current = current->next()));
#if DEBUG_VALIDATE
globalState.setPhase(SkOpPhase::kWalking);
#endif
bool success = HandleCoincidence(contourList, &coincidence);
#if DEBUG_COIN
globalState.debugAddToGlobalCoinDicts();
#endif
if (!success) {
return false;
}
#if DEBUG_ALIGNMENT
contourList->dumpSegments("aligned");
#endif
// construct closed contours
SkPath original = *result;
result->reset();
result->setFillType(fillType);
SkPathWriter wrapper(*result);
if (!bridgeOp(contourList, op, xorMask, xorOpMask, &wrapper)) {
*result = original;
return false;
}
wrapper.assemble(); // if some edges could not be resolved, assemble remaining
#if DEBUG_T_SECT_LOOP_COUNT
{
SkAutoMutexAcquire autoM(debugWorstLoop);
if (!gVerboseFinalize) {
gVerboseFinalize = &ReportPathOpsDebugging;
}
debugWorstState.debugDoYourWorst(&globalState);
}
#endif
return true;
}
bool Op(const SkPath& one, const SkPath& two, SkPathOp op, SkPath* result) {
#if DEBUG_DUMP_VERIFY
if (SkPathOpsDebug::gVerifyOp) {
if (!OpDebug(one, two, op, result SkDEBUGPARAMS(false) SkDEBUGPARAMS(nullptr))) {
SkPathOpsDebug::ReportOpFail(one, two, op);
return false;
}
SkPathOpsDebug::VerifyOp(one, two, op, *result);
return true;
}
#endif
return OpDebug(one, two, op, result SkDEBUGPARAMS(true) SkDEBUGPARAMS(nullptr));
}