path ops : add support for inverse fill

add inverse fill, reverse diff, and gm tests
cleaned up some interfaces
Review URL: https://codereview.chromium.org/14371011

git-svn-id: http://skia.googlecode.com/svn/trunk@8798 2bbb7eff-a529-9590-31e7-b0007b416f81

3 files changed, 41 insertions, 10 deletions

diff --git a/src/pathops/SkOpSegment.cpp b/src/pathops/SkOpSegment.cpp
index e221f68945..43afa08555 100644
--- a/src/pathops/SkOpSegment.cpp
+++ b/src/pathops/SkOpSegment.cpp
@@ -7,7 +7,7 @@
 #include "SkIntersections.h"
 #include "SkOpSegment.h"
 #include "SkPathWriter.h"
-#include "TSearch.h"
+#include "SkTSort.h"
 
 #define F (false)      // discard the edge
 #define T (true)       // keep the edge
@@ -18,7 +18,6 @@ static const bool gUnaryActiveEdge[2][2] = {
     {F, T}, {T, F},
 };
 
-// FIXME: add support for kReverseDifference_Op
 static const bool gActiveEdge[kXOR_PathOp + 1][2][2][2][2] = {
 //                 miFrom=0                              miFrom=1
 //         miTo=0            miTo=1              miTo=0             miTo=1
@@ -2318,7 +2317,7 @@ bool SkOpSegment::SortAngles(const SkTDArray<SkOpAngle>& angles,
         sortable &= !angle.unsortable();
     }
     if (sortable) {
-        QSort<SkOpAngle>(angleList->begin(), angleList->end() - 1);
+        SkTQSort<SkOpAngle>(angleList->begin(), angleList->end() - 1);
         for (angleIndex = 0; angleIndex < angleCount; ++angleIndex) {
             if (angles[angleIndex].unsortable()) {
                 sortable = false;
diff --git a/src/pathops/SkPathOpsOp.cpp b/src/pathops/SkPathOpsOp.cpp
index 5a3576ff6c..07a8babf7f 100644
--- a/src/pathops/SkPathOpsOp.cpp
+++ b/src/pathops/SkPathOpsOp.cpp
@@ -206,18 +206,48 @@ static bool bridgeOp(SkTDArray<SkOpContour*>& contourList, const SkPathOp op,
     return simple->someAssemblyRequired();
 }
 
+// pretty picture:
+// https://docs.google.com/a/google.com/drawings/d/1sPV8rPfpEFXymBp3iSbDRWAycp1b-7vD9JP2V-kn9Ss/edit?usp=sharing
+static const SkPathOp gOpInverse[kReverseDifference_PathOp + 1][2][2] = {
+//                  inside minuend                               outside minuend
+//     inside subtrahend     outside subtrahend      inside subtrahend     outside subtrahend
+    {{ kDifference_PathOp,    kIntersect_PathOp }, { kUnion_PathOp, kReverseDifference_PathOp }},
+    {{ kIntersect_PathOp,    kDifference_PathOp }, { kReverseDifference_PathOp, kUnion_PathOp }},
+    {{ kUnion_PathOp, kReverseDifference_PathOp }, { kDifference_PathOp,    kIntersect_PathOp }},
+    {{ kXOR_PathOp,                 kXOR_PathOp }, { kXOR_PathOp,                 kXOR_PathOp }},
+    {{ kReverseDifference_PathOp, kUnion_PathOp }, { kIntersect_PathOp,    kDifference_PathOp }},
+};
+
+static const bool gOutInverse[kReverseDifference_PathOp + 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
+};
+
 void Op(const SkPath& one, const SkPath& two, SkPathOp op, SkPath* result) {
+    op = gOpInverse[op][one.isInverseFillType()][two.isInverseFillType()];
+    result->reset();
+    SkPath::FillType fillType = gOutInverse[op][one.isInverseFillType()][two.isInverseFillType()]
+            ? SkPath::kInverseEvenOdd_FillType : SkPath::kEvenOdd_FillType;
+    result->setFillType(fillType);
+    const SkPath* minuend = &one;
+    const SkPath* subtrahend = &two;
+    if (op == kReverseDifference_PathOp) {
+        minuend = &two;
+        subtrahend = &one;
+        op = kDifference_PathOp;
+    }
 #if DEBUG_SORT || DEBUG_SWAP_TOP
     gDebugSortCount = gDebugSortCountDefault;
 #endif
-    result->reset();
-    result->setFillType(SkPath::kEvenOdd_FillType);
     // turn path into list of segments
     SkTArray<SkOpContour> contours;
     // FIXME: add self-intersecting cubics' T values to segment
-    SkOpEdgeBuilder builder(one, contours);
+    SkOpEdgeBuilder builder(*minuend, contours);
     const int xorMask = builder.xorMask();
-    builder.addOperand(two);
+    builder.addOperand(*subtrahend);
     builder.finish();
     const int xorOpMask = builder.xorMask();
     SkTDArray<SkOpContour*> contourList;
@@ -264,7 +294,7 @@ void Op(const SkPath& one, const SkPath& two, SkPathOp op, SkPath* result) {
     bridgeOp(contourList, op, xorMask, xorOpMask, &wrapper);
     {  // if some edges could not be resolved, assemble remaining fragments
         SkPath temp;
-        temp.setFillType(SkPath::kEvenOdd_FillType);
+        temp.setFillType(fillType);
         SkPathWriter assembled(temp);
         Assemble(wrapper, &assembled);
         *result = *assembled.nativePath();
diff --git a/src/pathops/SkPathOpsSimplify.cpp b/src/pathops/SkPathOpsSimplify.cpp
index 2213c68334..5c9d683f51 100644
--- a/src/pathops/SkPathOpsSimplify.cpp
+++ b/src/pathops/SkPathOpsSimplify.cpp
@@ -149,7 +149,9 @@ void Simplify(const SkPath& path, SkPath* result) {
 #endif
     // returns 1 for evenodd, -1 for winding, regardless of inverse-ness
     result->reset();
-    result->setFillType(SkPath::kEvenOdd_FillType);
+    SkPath::FillType fillType = path.isInverseFillType() ? SkPath::kInverseEvenOdd_FillType
+            : SkPath::kEvenOdd_FillType;
+    result->setFillType(fillType);
     SkPathWriter simple(*result);
 
     // turn path into list of segments
@@ -187,7 +189,7 @@ void Simplify(const SkPath& path, SkPath* result) {
                 : !bridgeXor(contourList, &simple))
     {  // if some edges could not be resolved, assemble remaining fragments
         SkPath temp;
-        temp.setFillType(SkPath::kEvenOdd_FillType);
+        temp.setFillType(fillType);
         SkPathWriter assembled(temp);
         Assemble(simple, &assembled);
         *result = *assembled.nativePath();