Implements the non-Porter-Duff compositing modes required for SVG's feBlend

element.  This filter has two inputs, since normal blending can't be used.  The
GPU side uses two filter stages to accomplish this:  one to sample the
background, and one to sample the foreground and blend it.

Review URL:  https://codereview.appspot.com/6463081/



git-svn-id: http://skia.googlecode.com/svn/trunk@5231 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 98 insertions, 0 deletions

diff --git a/gm/blend.cpp b/gm/blend.cpp
new file mode 100644
index 0000000000..d766a186d2
--- /dev/null
+++ b/gm/blend.cpp
@@ -0,0 +1,98 @@
+/*
+ * 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 "SkBlendImageFilter.h"
+#include "SkBitmapSource.h"
+
+namespace skiagm {
+
+class ImageBlendGM : public GM {
+public:
+    ImageBlendGM() : fInitialized(false) {
+        this->setBGColor(0xFF000000);
+    }
+    
+protected:
+    virtual SkString onShortName() {
+        return SkString("blend");
+    }
+
+    void make_bitmap() {
+        fBitmap.setConfig(SkBitmap::kARGB_8888_Config, 80, 80);
+        fBitmap.allocPixels();
+        SkDevice device(fBitmap);
+        SkCanvas canvas(&device);
+        canvas.clear(0x00000000);
+        SkPaint paint;
+        paint.setAntiAlias(true);
+        paint.setColor(0xD000D000);
+        paint.setTextSize(SkIntToScalar(96));
+        const char* str = "e";
+        canvas.drawText(str, strlen(str), SkIntToScalar(15), SkIntToScalar(65), paint);
+    }
+
+    void make_checkerboard() {
+        fCheckerboard.setConfig(SkBitmap::kARGB_8888_Config, 80, 80);
+        fCheckerboard.allocPixels();
+        SkDevice device(fCheckerboard);
+        SkCanvas canvas(&device);
+        canvas.clear(0x00000000);
+        SkPaint darkPaint;
+        darkPaint.setColor(0xFF404040);
+        SkPaint lightPaint;
+        lightPaint.setColor(0xFFA0A0A0);
+        for (int y = 0; y < 80; y += 16) {
+          for (int x = 0; x < 80; x += 16) {
+            canvas.save();
+            canvas.translate(x, y);
+            canvas.drawRect(SkRect::MakeXYWH(0, 0, 8, 8), darkPaint);
+            canvas.drawRect(SkRect::MakeXYWH(8, 0, 8, 8), lightPaint);
+            canvas.drawRect(SkRect::MakeXYWH(0, 8, 8, 8), lightPaint);
+            canvas.drawRect(SkRect::MakeXYWH(8, 8, 8, 8), darkPaint);
+            canvas.restore();
+          }
+        }
+    }
+
+    virtual SkISize onISize() {
+        return make_isize(500, 100);
+    }
+
+    virtual void onDraw(SkCanvas* canvas) {
+        if (!fInitialized) {
+            make_bitmap();
+            make_checkerboard();
+            fInitialized = true;
+        }
+        canvas->clear(0x00000000);
+        SkPaint paint;
+        SkAutoTUnref<SkImageFilter> background(SkNEW_ARGS(SkBitmapSource, (fCheckerboard)));
+        paint.setImageFilter(SkNEW_ARGS(SkBlendImageFilter, (SkBlendImageFilter::kNormal_Mode, background)))->unref();
+        canvas->drawSprite(fBitmap, 0, 0, &paint);
+        paint.setImageFilter(SkNEW_ARGS(SkBlendImageFilter, (SkBlendImageFilter::kMultiply_Mode, background)))->unref();
+        canvas->drawSprite(fBitmap, 100, 0, &paint);
+        paint.setImageFilter(SkNEW_ARGS(SkBlendImageFilter, (SkBlendImageFilter::kScreen_Mode, background)))->unref();
+        canvas->drawSprite(fBitmap, 200, 0, &paint);
+        paint.setImageFilter(SkNEW_ARGS(SkBlendImageFilter, (SkBlendImageFilter::kDarken_Mode, background)))->unref();
+        canvas->drawSprite(fBitmap, 300, 0, &paint);
+        paint.setImageFilter(SkNEW_ARGS(SkBlendImageFilter, (SkBlendImageFilter::kLighten_Mode, background)))->unref();
+        canvas->drawSprite(fBitmap, 400, 0, &paint);
+    }
+    
+private:
+    typedef GM INHERITED;
+    SkBitmap fBitmap, fCheckerboard;
+    bool fInitialized;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+static GM* MyFactory(void*) { return new ImageBlendGM; }
+static GMRegistry reg(MyFactory);
+
+}