add interp path

src/core/SkPathRef.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBuffer.h"
 #include "SkOncePtr.h"
 #include "SkPath.h"
@@ skipping 281 matching lines @@
     if (!fBoundsIsDirty) {
         fBounds = ref.fBounds;
         fIsFinite = ref.fIsFinite;
     }
     fSegmentMask = ref.fSegmentMask;
     fIsOval = ref.fIsOval;
     fIsRRect = ref.fIsRRect;
     SkDEBUGCODE(this->validate();)
 }
 
+
+void SkPathRef::interpolate(const SkPathRef& ending, SkScalar weight, SkPathRef* out) const {
+    const SkScalar* inValues = &ending.getPoints()->fX;
+    SkScalar* outValues = &out->getPoints()->fX;
+    int count = out->countPoints() * 2;
+    for (int index = 0; index < count; ++index) {
+        outValues[index] = outValues[index] * weight + inValues[index] * (1 - weight);
+    }
+    out->fBoundsIsDirty = true;
+    out->fIsOval = false;
+    out->fIsRRect = false;
+}
+
 SkPoint* SkPathRef::growForRepeatedVerb(int /*SkPath::Verb*/ verb,
                                         int numVbs,
                                         SkScalar** weights) {
     // This value is just made-up for now. When count is 4, calling memset was much
     // slower than just writing the loop. This seems odd, and hopefully in the
     // future this will appear to have been a fluke...
     static const unsigned int kMIN_COUNT_FOR_MEMSET_TO_BE_FAST = 16;
 
     SkDEBUGCODE(this->validate();)
     int pCnt;
@@ skipping 342 matching lines @@
                 break;
             default:
                 SkDEBUGFAIL("Unknown Verb");
                 break;
         }
     }
     SkASSERT(mask == fSegmentMask);
 #endif // SK_DEBUG_PATH
 }
 #endif