add drawImageNine

src/core/SkNinePatchIter.h

Index: src/core/SkNinePatchIter.h
diff --git a/src/core/SkNinePatchIter.h b/src/core/SkNinePatchIter.h
new file mode 100644
index 0000000000000000000000000000000000000000..2d7e9a8b195ea3cf3c093134eb4a8b032ac64fb2
--- /dev/null
+++ b/src/core/SkNinePatchIter.h
@@ -0,0 +1,42 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkNinePatchIter_DEFINED
+#define SkNinePatchIter_DEFINED
+
+#include "SkScalar.h"
+
+struct SkIRect;
+struct SkRect;
+
+/**
+ *  Disect a ninepatch request into an sequence of src-rect / dst-rect pairs
+ */
+class SkNinePatchIter {
+public:
+    static bool Valid(int imageWidth, int imageHeight, const SkIRect& center);
+
+    SkNinePatchIter(int imageWidth, int imageHeight, const SkIRect& center, const SkRect& dst);
+
+    /**
+     *  While it returns true, use src/dst to draw the image/bitmap
+     */
+    bool next(SkRect* src, SkRect* dst);
+    
+private:
+    SkScalar fSrcX[4];
+    SkScalar fSrcY[4];
+    SkScalar fDstX[4];
+    SkScalar fDstY[4];
+    
+    int fCurrX;
+    int fCurrY;
+    bool fDone;
+};
+
+#endif
+