Add drawRegion() API to SkCanvas

gm/drawregionrotate.cpp

+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "gm.h"
+#include "SkCanvas.h"
+
+class DrawRegionRotateGM : public skiagm::GM {
+public:
+    DrawRegionRotateGM() {}
+
+protected:
+    SkString onShortName() override {
+        return SkString("drawregionrotate");
+    }
+
+    SkISize onISize() override {
+        return SkISize::Make(300, 300);
+    }
+
+    void onOnceBeforeDraw() override {
+        fRegion.op( 50,  50, 100, 100, SkRegion::kUnion_Op);
+        fRegion.op( 50, 100, 100, 150, SkRegion::kUnion_Op);
+        fRegion.op(100,  50, 150, 100, SkRegion::kUnion_Op);
+        fRegion.op(100, 100, 150, 150, SkRegion::kUnion_Op);
+    }
+
+    void onDraw(SkCanvas* canvas) override {

[msarett, 2016/08/25 13:02:32]

I wanted to write a gm that shows interior cracks when we don't use the path
implementation.  This one isn't working for me.  Brian, any thoughts?

[msarett, 2016/08/25 15:07:35]

Problem was that SkRegion was smartly combining all my rects into a single rect,
thanks Brian for catching this.

+        SkPaint paint;
+        paint.setStyle(SkPaint::kFill_Style);
+        paint.setColor(0x70000000);
+        paint.setAntiAlias(true);
+
+        canvas->translate(100, 0);
+        canvas->rotate(45);
+        canvas->drawRegion(fRegion, paint);
+    }
+
+    SkRegion fRegion;
+
+private:
+    typedef skiagm::GM INHERITED;
+};
+DEF_GM( return new DrawRegionRotateGM; )