Create a new GM to exercise ComposeShader.

Code borrowed from samplecode/SampleShaders.cpp

Review URL: https://codereview.appspot.com/6371043

git-svn-id: http://skia.googlecode.com/svn/trunk@4407 2bbb7eff-a529-9590-31e7-b0007b416f81

gm/composeshader.cpp

@@ -0,0 +1,88 @@
+
+/*
+ * Copyright 2012 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 "SkComposeShader.h"
+#include "SkGradientShader.h"
+#include "SkGraphics.h"
+#include "SkShader.h"
+#include "SkString.h"
+#include "SkXfermode.h"
+
+namespace skiagm {
+
+class ShaderGM : public GM {
+public:
+    ShaderGM() {
+        SkPoint pts[2];
+        SkColor colors[2];
+
+        pts[0].set(0, 0);
+        pts[1].set(SkIntToScalar(100), 0);
+        colors[0] = SK_ColorRED;
+        colors[1] = SK_ColorBLUE;
+        SkShader* shaderA = SkGradientShader::CreateLinear(pts, colors, NULL, 2,
+                                                           SkShader::kClamp_TileMode);
+
+        pts[0].set(0, 0);
+        pts[1].set(0, SkIntToScalar(100));
+        colors[0] = SK_ColorBLACK;
+        colors[1] = SkColorSetARGB(0x80, 0, 0, 0);
+        SkShader* shaderB = SkGradientShader::CreateLinear(pts, colors, NULL, 2,
+                                                           SkShader::kClamp_TileMode);
+
+        SkXfermode* mode = SkXfermode::Create(SkXfermode::kDstIn_Mode);
+
+        fShader = new SkComposeShader(shaderA, shaderB, mode);
+        shaderA->unref();
+        shaderB->unref();
+        mode->unref();
+    }
+
+    virtual ~ShaderGM() {
+        SkSafeUnref(fShader);
+    }
+
+protected:
+    virtual SkString onShortName() SK_OVERRIDE {
+        return SkString("composeshader");
+    }
+
+    virtual SkISize onISize() SK_OVERRIDE {
+        return make_isize(640, 480);
+    }
+
+    virtual uint32_t onGetFlags() const SK_OVERRIDE {
+        return this->INHERITED::onGetFlags() | GM::kSkipPDF_Flag;
+    }
+
+    virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
+
+        SkPaint paint;
+        SkRect  r;
+
+        paint.setColor(SK_ColorGREEN);
+        canvas->drawRectCoords(0, 0, SkIntToScalar(100), SkIntToScalar(100), paint);
+        paint.setShader(fShader);
+        canvas->drawRectCoords(0, 0, SkIntToScalar(100), SkIntToScalar(100), paint);
+    }
+
+private:
+    SkShader*   fShader;
+    typedef GM INHERITED ;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+static GM* MyFactory(void*) { return new ShaderGM; }
+static GMRegistry reg(MyFactory);
+
+} // namespace
+

gyp/gmslides.gypi

@@ -13,6 +13,7 @@
     '../gm/colormatrix.cpp',
     '../gm/complexclip.cpp',
     '../gm/complexclip2.cpp',
+    '../gm/composeshader.cpp',
     '../gm/convexpaths.cpp',
     '../gm/cubicpaths.cpp',
     '../gm/cmykjpeg.cpp',