Add drawRegion() API to SkCanvas

gm/drawregionmodes.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 "SkBlurMaskFilter.h"
+#include "SkCanvas.h"
+#include "SkDashPathEffect.h"
+#include "SkGradientShader.h"
+#include "SkImageFilter.h"
+
+class DrawRegionModesGM : public skiagm::GM {
+public:
+    DrawRegionModesGM() {}
+
+protected:
+    SkString onShortName() override {
+        return SkString("drawregionmodes");
+    }
+
+    SkISize onISize() override {
+        return SkISize::Make(375, 500);
+    }
+
+    void onOnceBeforeDraw() override {
+        fRegion.op( 50,  50, 100, 100, SkRegion::kUnion_Op);
+        fRegion.op( 50, 100, 150, 150, SkRegion::kUnion_Op);
+    }
+
+    void onDraw(SkCanvas* canvas) override {
+        canvas->clear(SK_ColorGREEN);
+
+        SkPaint paint;
+        paint.setStyle(SkPaint::kFill_Style);
+        paint.setColor(0xFFFF0000);
+        paint.setAntiAlias(true);
+
+        canvas->translate(-50.0f, 75.0f);
+        canvas->rotate(-45.0f);
+        canvas->drawRegion(fRegion, paint);
+
+        canvas->translate(125.0f, 125.0f);
+        paint.setImageFilter(SkImageFilter::MakeBlur(5.0f, 5.0f, nullptr, nullptr));
+        canvas->drawRegion(fRegion, paint);
+
+        canvas->translate(-125.0f, 125.0f);
+        paint.setImageFilter(nullptr);
+        SkRect occluder = SkRect::MakeEmpty();
+        paint.setMaskFilter(SkBlurMaskFilter::Make(kNormal_SkBlurStyle, 5.0f, occluder, 0));
+        canvas->drawRegion(fRegion, paint);
+
+        canvas->translate(-125.0f, -125.0f);
+        paint.setMaskFilter(nullptr);
+        paint.setStyle(SkPaint::kStroke_Style);
+        float intervals[] = { 5.0f, 5.0f };
+        paint.setPathEffect(SkDashPathEffect::Make(intervals, 2, 2.5f));
+        canvas->drawRegion(fRegion, paint);
+
+        canvas->setMatrix(SkMatrix::I());
+        canvas->translate(100, 325);
+        paint.setPathEffect(nullptr);
+        paint.setStyle(SkPaint::kFill_Style);
+        SkPoint points[] = { SkPoint::Make(50.0f, 50.0f), SkPoint::Make(150.0f, 150.0f) };
+        SkColor colors[] = { SK_ColorBLUE, SK_ColorYELLOW };
+        paint.setShader(SkGradientShader::MakeLinear(points, colors, nullptr, 2,
+                                                     SkShader::kClamp_TileMode));
+        canvas->drawRegion(fRegion, paint);
+    }
+
+    SkRegion fRegion;
+
+private:
+    typedef skiagm::GM INHERITED;
+};
+DEF_GM( return new DrawRegionModesGM; )