Add base types for path ops
Paths contain lines, quads, and cubics, which are
collectively curves.
To work with path intersections, intermediary curves
are constructed. For now, those intermediates use
doubles to guarantee sufficient precision.
The DVector, DPoint, DLine, DQuad, and DCubic
structs encapsulate these intermediate curves.
The DRect and DTriangle structs are created to
describe intersectable areas of interest.
The Bounds struct inherits from SkRect to create
a SkScalar-based rectangle that intersects shared
edges.
This also includes common math equalities and
debugging that the remainder of path ops builds on,
as well as a temporary top-level interface in
include/pathops/SkPathOps.h.
Review URL: https://codereview.chromium.org/12827020
git-svn-id: http://skia.googlecode.com/svn/trunk@8551 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/pathops/SkPathOpsSimplify.cpp b/src/pathops/SkPathOpsSimplify.cpp
new file mode 100644
index 0000000..2213c68
--- /dev/null
+++ b/src/pathops/SkPathOpsSimplify.cpp
@@ -0,0 +1,195 @@
+/*
+ * 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 "SkOpEdgeBuilder.h"
+#include "SkPathOpsCommon.h"
+#include "SkPathWriter.h"
+
+static bool bridgeWinding(SkTDArray<SkOpContour*>& contourList, SkPathWriter* simple) {
+ bool firstContour = true;
+ bool unsortable = false;
+ bool topUnsortable = false;
+ SkPoint topLeft = {SK_ScalarMin, SK_ScalarMin};
+ do {
+ int index, endIndex;
+ bool topDone;
+ SkOpSegment* current = FindSortableTop(contourList, &firstContour, &index, &endIndex,
+ &topLeft, &topUnsortable, &topDone, false);
+ if (!current) {
+ if (topUnsortable || !topDone) {
+ topUnsortable = false;
+ SkASSERT(topLeft.fX != SK_ScalarMin && topLeft.fY != SK_ScalarMin);
+ topLeft.fX = topLeft.fY = SK_ScalarMin;
+ continue;
+ }
+ break;
+ }
+ SkTDArray<SkOpSpan*> chaseArray;
+ do {
+ if (current->activeWinding(index, endIndex)) {
+ do {
+ #if DEBUG_ACTIVE_SPANS
+ if (!unsortable && current->done()) {
+ DebugShowActiveSpans(contourList);
+ }
+ #endif
+ SkASSERT(unsortable || !current->done());
+ int nextStart = index;
+ int nextEnd = endIndex;
+ SkOpSegment* next = current->findNextWinding(&chaseArray, &nextStart, &nextEnd,
+ &unsortable);
+ if (!next) {
+ if (!unsortable && simple->hasMove()
+ && current->verb() != SkPath::kLine_Verb
+ && !simple->isClosed()) {
+ current->addCurveTo(index, endIndex, simple, true);
+ SkASSERT(simple->isClosed());
+ }
+ break;
+ }
+ #if DEBUG_FLOW
+ SkDebugf("%s current id=%d from=(%1.9g,%1.9g) to=(%1.9g,%1.9g)\n", __FUNCTION__,
+ current->debugID(), current->xyAtT(index).fX, current->xyAtT(index).fY,
+ current->xyAtT(endIndex).fX, current->xyAtT(endIndex).fY);
+ #endif
+ current->addCurveTo(index, endIndex, simple, true);
+ current = next;
+ index = nextStart;
+ endIndex = nextEnd;
+ } while (!simple->isClosed() && (!unsortable
+ || !current->done(SkMin32(index, endIndex))));
+ if (current->activeWinding(index, endIndex) && !simple->isClosed()) {
+ SkASSERT(unsortable);
+ int min = SkMin32(index, endIndex);
+ if (!current->done(min)) {
+ current->addCurveTo(index, endIndex, simple, true);
+ current->markDoneUnary(min);
+ }
+ }
+ simple->close();
+ } else {
+ SkOpSpan* last = current->markAndChaseDoneUnary(index, endIndex);
+ if (last && !last->fLoop) {
+ *chaseArray.append() = last;
+ }
+ }
+ current = FindChase(chaseArray, index, endIndex);
+ #if DEBUG_ACTIVE_SPANS
+ DebugShowActiveSpans(contourList);
+ #endif
+ if (!current) {
+ break;
+ }
+ } while (true);
+ } while (true);
+ return simple->someAssemblyRequired();
+}
+
+// returns true if all edges were processed
+static bool bridgeXor(SkTDArray<SkOpContour*>& contourList, SkPathWriter* simple) {
+ SkOpSegment* current;
+ int start, end;
+ bool unsortable = false;
+ bool closable = true;
+ while ((current = FindUndone(contourList, &start, &end))) {
+ do {
+ #if DEBUG_ACTIVE_SPANS
+ if (!unsortable && current->done()) {
+ DebugShowActiveSpans(contourList);
+ }
+ #endif
+ SkASSERT(unsortable || !current->done());
+ int nextStart = start;
+ int nextEnd = end;
+ SkOpSegment* next = current->findNextXor(&nextStart, &nextEnd, &unsortable);
+ if (!next) {
+ if (!unsortable && simple->hasMove()
+ && current->verb() != SkPath::kLine_Verb
+ && !simple->isClosed()) {
+ current->addCurveTo(start, end, simple, true);
+ SkASSERT(simple->isClosed());
+ }
+ break;
+ }
+ #if DEBUG_FLOW
+ SkDebugf("%s current id=%d from=(%1.9g,%1.9g) to=(%1.9g,%1.9g)\n", __FUNCTION__,
+ current->debugID(), current->xyAtT(start).fX, current->xyAtT(start).fY,
+ current->xyAtT(end).fX, current->xyAtT(end).fY);
+ #endif
+ current->addCurveTo(start, end, simple, true);
+ current = next;
+ start = nextStart;
+ end = nextEnd;
+ } while (!simple->isClosed() && (!unsortable || !current->done(SkMin32(start, end))));
+ if (!simple->isClosed()) {
+ SkASSERT(unsortable);
+ int min = SkMin32(start, end);
+ if (!current->done(min)) {
+ current->addCurveTo(start, end, simple, true);
+ current->markDone(min, 1);
+ }
+ closable = false;
+ }
+ simple->close();
+ #if DEBUG_ACTIVE_SPANS
+ DebugShowActiveSpans(contourList);
+ #endif
+ }
+ return closable;
+}
+
+// FIXME : add this as a member of SkPath
+void Simplify(const SkPath& path, SkPath* result) {
+#if DEBUG_SORT || DEBUG_SWAP_TOP
+ gDebugSortCount = gDebugSortCountDefault;
+#endif
+ // returns 1 for evenodd, -1 for winding, regardless of inverse-ness
+ result->reset();
+ result->setFillType(SkPath::kEvenOdd_FillType);
+ SkPathWriter simple(*result);
+
+ // turn path into list of segments
+ SkTArray<SkOpContour> contours;
+ SkOpEdgeBuilder builder(path, contours);
+ builder.finish();
+ SkTDArray<SkOpContour*> contourList;
+ MakeContourList(contours, contourList, false, false);
+ SkOpContour** currentPtr = contourList.begin();
+ if (!currentPtr) {
+ return;
+ }
+ SkOpContour** listEnd = contourList.end();
+ // find all intersections between segments
+ do {
+ SkOpContour** nextPtr = currentPtr;
+ SkOpContour* current = *currentPtr++;
+ if (current->containsCubics()) {
+ AddSelfIntersectTs(current);
+ }
+ SkOpContour* next;
+ do {
+ next = *nextPtr++;
+ } while (AddIntersectTs(current, next) && nextPtr != listEnd);
+ } while (currentPtr != listEnd);
+ // eat through coincident edges
+ CoincidenceCheck(&contourList, 0);
+ FixOtherTIndex(&contourList);
+ SortSegments(&contourList);
+#if DEBUG_ACTIVE_SPANS
+ DebugShowActiveSpans(contourList);
+#endif
+ // construct closed contours
+ if (builder.xorMask() == kWinding_PathOpsMask ? bridgeWinding(contourList, &simple)
+ : !bridgeXor(contourList, &simple))
+ { // if some edges could not be resolved, assemble remaining fragments
+ SkPath temp;
+ temp.setFillType(SkPath::kEvenOdd_FillType);
+ SkPathWriter assembled(temp);
+ Assemble(simple, &assembled);
+ *result = *assembled.nativePath();
+ }
+}