[SkSVGDevice] Initial clipping support

src/core/SkClipStack.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkCanvas.h"
 #include "SkClipStack.h"
 #include "SkPath.h"
+#include "SkPathOps.h"
 #include "SkThread.h"
 
 #include <new>
 
 
 // 0-2 are reserved for invalid, empty & wide-open
 static const int32_t kFirstUnreservedGenID = 3;
 int32_t SkClipStack::gGenID = kFirstUnreservedGenID;
 
 SkClipStack::Element::Element(const Element& that) {
@@ skipping 637 matching lines @@
             }
         }
         if (SkRegion::kReplace_Op == element->getOp()) {
             break;
         }
         element = iter.prev();
     }
     return true;
 }
 
+bool SkClipStack::asPath(SkPath *path) const {
+    bool isAA = false;
+
+    path->reset();
+    path->setFillType(SkPath::kInverseEvenOdd_FillType);
+
+    SkClipStack::Iter iter(*this, SkClipStack::Iter::kBottom_IterStart);
+    while (const SkClipStack::Element* element = iter.next()) {
+        SkPath operand;
+        if (element->getType() != SkClipStack::Element::kEmpty_Type) {
+            element->asPath(&operand);
+        }
+
+        SkRegion::Op elementOp = element->getOp();
+        if (elementOp == SkRegion::kReplace_Op) {
+            *path = operand;
+        } else {
+            Op(*path, operand, (SkPathOp)elementOp, path);
+        }
+
+        // if the prev and curr clips disagree about aa -vs- not, favor the aa request.
+        // perhaps we need an API change to avoid this sort of mixed-signals about
+        // clipping.
+        isAA = (isAA || element->isAA());
+    }
+
+    return isAA;
+}
+
 void SkClipStack::pushElement(const Element& element) {
     // Use reverse iterator instead of back because Rect path may need previous
     SkDeque::Iter iter(fDeque, SkDeque::Iter::kBack_IterStart);
     Element* prior = (Element*) iter.prev();
 
     if (prior) {
         if (prior->canBeIntersectedInPlace(fSaveCount, element.getOp())) {
             switch (prior->fType) {
                 case Element::kEmpty_Type:
                     SkDEBUGCODE(prior->checkEmpty();)
@@ skipping 223 matching lines @@
 
 void SkClipStack::dump() const {
     B2TIter iter(*this);
     const Element* e;
     while ((e = iter.next())) {
         e->dump();
         SkDebugf("\n");
     }
 }
 #endif