A simple gradient test

Change-Id: Ic3e53f7eab747f63641e0eb6a1c73ad0833acef6
Reviewed-on: https://skia-review.googlesource.com/8158
Reviewed-by: Matt Sarett <msarett@google.com>
Commit-Queue: Tenghui Zhu <ztenghui@google.com>

gm/testgradient.cpp

@@ -0,0 +1,71 @@
+/*
+ * Copyright 2017 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"
+#include "SkGradientShader.h"
+#include "SkRRect.h"
+
+class TestGradientGM : public skiagm::GM {
+public:
+    TestGradientGM() {}
+
+protected:
+    SkString onShortName() override {
+        return SkString("testgradient");
+    }
+
+    SkISize onISize() override {
+        return SkISize::Make(800, 800);
+    }
+
+    void onDraw(SkCanvas* canvas) override {
+        // Set up a gradient paint for a rect.
+        // And non-gradient paint for other objects.
+        canvas->drawColor(SK_ColorWHITE);
+
+        SkPaint paint;
+        paint.setStyle(SkPaint::kFill_Style);
+        paint.setAntiAlias(true);
+        paint.setStrokeWidth(4);
+        paint.setColor(0xFFFE938C);
+
+        SkRect rect = SkRect::MakeXYWH(10, 10, 100, 160);
+
+        SkPoint points[2] = {
+            SkPoint::Make(0.0f, 0.0f),
+            SkPoint::Make(256.0f, 256.0f)
+        };
+        SkColor colors[2] = {SK_ColorBLUE, SK_ColorYELLOW};
+        SkPaint newPaint(paint);
+        newPaint.setShader(SkGradientShader::MakeLinear(
+                points, colors, nullptr, 2,
+                SkShader::kClamp_TileMode, 0, nullptr));
+        canvas->drawRect(rect, newPaint);
+
+        SkRRect oval;
+        oval.setOval(rect);
+        oval.offset(40, 80);
+        paint.setColor(0xFFE6B89C);
+        canvas->drawRRect(oval, paint);
+
+        paint.setColor(0xFF9CAFB7);
+        canvas->drawCircle(180, 50, 25, paint);
+
+        rect.offset(80, 50);
+        paint.setColor(0xFF4281A4);
+        paint.setStyle(SkPaint::kStroke_Style);
+        canvas->drawRoundRect(rect, 10, 10, paint);
+    }
+
+private:
+    typedef skiagm::GM INHERITED;
+};
+
+// Register the GM
+DEF_GM( return new TestGradientGM; )

gn/gm.gni

@@ -279,6 +279,7 @@ gm_sources = [
   "$_gm/surface.cpp",
   "$_gm/tablecolorfilter.cpp",
   "$_gm/tallstretchedbitmaps.cpp",
+  "$_gm/testgradient.cpp",
   "$_gm/texdata.cpp",
   "$_gm/textblob.cpp",
   "$_gm/textblobblockreordering.cpp",