Add GM to test bitmap shaders with basic geometry and bitmap masks.

gm/bitmapshader.cpp

Index: gm/bitmapshader.cpp
diff --git a/gm/bitmapshader.cpp b/gm/bitmapshader.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..4ec234898cbea08b0d17842a3571111a939da846
--- /dev/null
+++ b/gm/bitmapshader.cpp
@@ -0,0 +1,103 @@
+
+/*
+ * 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 "SkBitmap.h"
+#include "SkPaint.h"
+#include "SkShader.h"
+
+namespace skiagm {
+
+static void draw_bm(SkBitmap* bm) {
+	SkPaint bluePaint;
+	bluePaint.setColor(SK_ColorBLUE);
+
+	bm->setConfig(SkBitmap::kARGB_8888_Config, 20, 20);
+	bm->allocPixels();
+	bm->eraseColor(SK_ColorRED);
+
+	SkCanvas canvas(*bm);
+	canvas.drawCircle(10, 10, 5, bluePaint);
+}
+
+static void draw_mask(SkBitmap* bm) {
+	SkPaint circlePaint;
+	circlePaint.setColor(SK_ColorBLACK);
+
+	bm->setConfig(SkBitmap::kA8_Config, 20, 20);
+	bm->allocPixels();
+	bm->eraseColor(SK_ColorTRANSPARENT);
+
+	SkCanvas canvas(*bm);
+	canvas.drawCircle(10, 10, 10, circlePaint);
+}
+
+class BitmapShaderGM : public GM {
+public:
+
+    BitmapShaderGM() {
+        this->setBGColor(SK_ColorGRAY);
+        draw_bm(&fBitmap);
+        draw_mask(&fMask);
+    }
+
+protected:
+    virtual SkString onShortName() {
+        return SkString("bitmapshaders");
+    }
+
+    virtual SkISize onISize() {
+        return make_isize(75, 100);
+    }
+
+    virtual void onDraw(SkCanvas* canvas) {
+    	SkShader* shader = SkShader::CreateBitmapShader(fBitmap,
+    			                                        SkShader::kClamp_TileMode,
+    			                                        SkShader::kClamp_TileMode);
+    	SkPaint paint;
+    	paint.setShader(shader);
+    	// release the shader ref as the paint now holds a reference
+    	shader->unref();
+
+    	// draw the shader with a bitmap mask
+    	canvas->drawBitmap(fMask, 0, 0, &paint);
+    	canvas->drawBitmap(fMask, 30, 0, &paint);
+
+       	canvas->translate(0, 25);
+
+    	// draw the shader with standard geometry
+       	canvas->drawCircle(10, 10, 10, paint);
+       	canvas->drawCircle(40, 10, 10, paint); // no blue circle expected
+
+       	canvas->translate(0, 25);
+
+    	shader = SkShader::CreateBitmapShader(fMask,
+    	                                      SkShader::kRepeat_TileMode,
+    	                                      SkShader::kRepeat_TileMode);
+    	paint.setShader(shader);
+    	paint.setColor(SK_ColorRED);
+    	shader->unref();
+
+       	// draw the mask using the shader and a color
+       	canvas->drawRect(SkRect::MakeXYWH(0, 0, 20, 20), paint);
+       	canvas->drawRect(SkRect::MakeXYWH(30, 0, 20, 20), paint);
+    }
+
+private:
+    SkBitmap fBitmap;
+    SkBitmap fMask;
+
+    typedef GM INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+static GM* MyFactory(void*) { return new BitmapShaderGM; }
+static GMRegistry reg(MyFactory);
+
+}