[PDF] Add GM and infrastructure to test drawing shaders with an initial transform.

Review URL: https://codereview.appspot.com/5867047

git-svn-id: http://skia.googlecode.com/svn/trunk@3450 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gm/shaderbounds.cpp b/gm/shaderbounds.cpp
new file mode 100644
index 0000000..d301f6c
--- /dev/null
+++ b/gm/shaderbounds.cpp
@@ -0,0 +1,105 @@
+/*
+ * 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 "SkGradientShader.h"
+
+namespace skiagm {
+
+static SkShader* MakeLinear(SkScalar width, SkScalar height, bool alternate) {
+  SkPoint pts[2] = { {0, 0}, {width, height}};
+  SkColor colors[2] = {SK_ColorRED, SK_ColorGREEN};
+  if (alternate) {
+    pts[1].fY = 0;
+    colors[0] = SK_ColorBLUE;
+    colors[1] = SK_ColorYELLOW;
+  }
+  return SkGradientShader::CreateLinear(pts, colors, NULL, 2,
+                                        SkShader::kClamp_TileMode, NULL);
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+class ShaderBoundsGM : public GM {
+public:
+    typedef SkShader* (*ShaderGenFunc)(SkScalar width, SkScalar height,
+                                       bool alternate);
+    ShaderBoundsGM(ShaderGenFunc maker, const SkString& name)
+        : fShaderMaker(maker),
+          fName(name) {
+    }
+
+protected:
+    SkString onShortName() {
+        return fName;
+    }
+
+    virtual SkISize onISize() { return make_isize(320, 240); }
+
+    virtual SkMatrix onGetInitialTransform() const SK_OVERRIDE {
+        SkMatrix result;
+        SkScalar scale = SkFloatToScalar(0.8f);
+        result.setScale(scale, scale);
+        result.postTranslate(7, 23);
+        return result;
+    }
+
+    virtual void onDraw(SkCanvas* canvas) {
+        // The PDF device has already clipped to the content area, but we
+        // do it again here so that the raster and pdf results are consistent.
+        canvas->clipRect(SkRect::MakeWH(320, 240));
+
+        SkMatrix canvasScale;
+        SkScalar scale = SkFloatToScalar(0.7f);
+        canvasScale.setScale(scale, scale);
+        canvas->concat(canvasScale);
+
+        // Background shader.
+        SkPaint paint;
+        paint.setShader(MakeShader(559, 387, false))->unref();
+        SkRect r = SkRect::MakeXYWH(SkIntToScalar(-12), SkIntToScalar(-41),
+                                    SkIntToScalar(571), SkIntToScalar(428));
+        canvas->drawRect(r, paint);
+
+        // Constrained shader.
+        paint.setShader(MakeShader(101, 151, true))->unref();
+        r = SkRect::MakeXYWH(SkIntToScalar(43), SkIntToScalar(71),
+                             SkIntToScalar(101), SkIntToScalar(151));
+        canvas->clipRect(r);
+        canvas->drawRect(r, paint);
+    }
+
+    SkShader* MakeShader(int width, int height, bool background) {
+        SkScalar scale = SkFloatToScalar(0.5f);
+        if (background) {
+            scale = SkFloatToScalar(0.6f);
+        }
+        SkScalar shaderWidth = SkIntToScalar(width)/scale;
+        SkScalar shaderHeight = SkIntToScalar(height)/scale;
+        SkShader* shader = fShaderMaker(shaderWidth, shaderHeight, background);
+        SkMatrix shaderScale;
+        shaderScale.setScale(scale, scale);
+        shader->setLocalMatrix(shaderScale);
+        return shader;
+    }
+
+private:
+    typedef GM INHERITED;
+
+    ShaderGenFunc fShaderMaker;
+    SkString fName;
+
+    SkShader* MakeShader(bool background);
+};
+
+///////////////////////////////////////////////////////////////////////////////
+
+static GM* MyFactory(void*) {
+    return new ShaderBoundsGM(MakeLinear, SkString("shaderbounds_linear"));
+}
+static GMRegistry reg(MyFactory);
+
+}