add new gms for shallow_gradient, in preparation for improving their quality



git-svn-id: http://skia.googlecode.com/svn/trunk@7544 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gm/shallowgradient.cpp b/gm/shallowgradient.cpp
new file mode 100644
index 0000000..672193d
--- /dev/null
+++ b/gm/shallowgradient.cpp
@@ -0,0 +1,77 @@
+/*
+ * Copyright 2013 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 "SkGradientShader.h"
+
+typedef SkShader* (*MakeShaderProc)(const SkColor[], int count, const SkSize&);
+
+static SkShader* shader_linear(const SkColor colors[], int count, const SkSize& size) {
+    SkPoint pts[] = { { 0, 0 }, { size.width(), size.height() } };
+    return SkGradientShader::CreateLinear(pts, colors, NULL, count,
+                                          SkShader::kClamp_TileMode);
+}
+
+static SkShader* shader_radial(const SkColor colors[], int count, const SkSize& size) {
+    SkPoint center = { size.width()/2, size.height()/2 };
+    return SkGradientShader::CreateRadial(center, size.width()/2, colors, NULL, count,
+                                          SkShader::kClamp_TileMode);
+}
+
+static SkShader* shader_conical(const SkColor colors[], int count, const SkSize& size) {
+    SkPoint center = { size.width()/2, size.height()/2 };
+    return SkGradientShader::CreateTwoPointConical(center, size.width()/64,
+                                                   center, size.width()/2,
+                                                   colors, NULL, count,
+                                                   SkShader::kClamp_TileMode);
+}
+
+static SkShader* shader_sweep(const SkColor colors[], int count, const SkSize& size) {
+    return SkGradientShader::CreateSweep(size.width()/2, size.height()/2,
+                                         colors, NULL, count);
+}
+
+class ShallowGradientGM : public skiagm::GM {
+public:
+    ShallowGradientGM(MakeShaderProc proc, const char name[]) : fProc(proc) {
+        fName.printf("shallow_gradient_%s", name);
+    }
+
+protected:
+    virtual SkString onShortName() SK_OVERRIDE {
+        return fName;
+    }
+
+    virtual SkISize onISize() SK_OVERRIDE {
+        return SkISize::Make(800, 800);
+    }
+
+    virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
+        const SkColor colors[] = { 0xFF555555, 0xFF444444 };
+        const int colorCount = SK_ARRAY_COUNT(colors);
+
+        SkRect r = { 0, 0, this->width(), this->height() };
+        SkSize size = SkSize::Make(r.width(), r.height());
+
+        SkPaint paint;
+        paint.setShader(fProc(colors, colorCount, size));
+        canvas->drawRect(r, paint);
+    }
+
+private:
+    MakeShaderProc fProc;
+    SkString fName;
+
+    typedef skiagm::GM INHERITED;
+};
+
+///////////////////////////////////////////////////////////////////////////////
+
+DEF_GM( return new ShallowGradientGM(shader_linear, "linear"); )
+DEF_GM( return new ShallowGradientGM(shader_radial, "radial"); )
+DEF_GM( return new ShallowGradientGM(shader_conical, "conical"); )
+DEF_GM( return new ShallowGradientGM(shader_sweep, "sweep"); )