Add AlphaThreshold filter.

gm/imagealphathreshold.cpp

Index: gm/imagealphathreshold.cpp
diff --git a/gm/imagemagnifier.cpp b/gm/imagealphathreshold.cpp
similarity index 63%
copy from gm/imagemagnifier.cpp
copy to gm/imagealphathreshold.cpp
index ae639d3b538b162b64a40b5604d041ddaea5d553..307c9c8c431449ffc0af5fe54971922d9612527b 100644
--- a/gm/imagemagnifier.cpp
+++ b/gm/imagealphathreshold.cpp
@@ -1,12 +1,12 @@
 /*
- * Copyright 2012 Google Inc.
+ * 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 "SkMagnifierImageFilter.h"
+#include "SkAlphaThresholdFilter.h"
 #include "SkRandom.h"
 
 #define WIDTH 500
@@ -14,20 +14,19 @@
 
 namespace skiagm {
 
-class ImageMagnifierGM : public GM {
+class ImageAlphaThresholdGM : public GM {
 public:
-    ImageMagnifierGM() {
+    ImageAlphaThresholdGM() {
         this->setBGColor(0xFF000000);
     }
 
 protected:
     virtual uint32_t onGetFlags() const SK_OVERRIDE {
-        // Skip tiled drawing until https://code.google.com/p/skia/issues/detail?id=781 is fixed.
         return this->INHERITED::onGetFlags() | GM::kSkipTiled_Flag;
     }
 
     virtual SkString onShortName() SK_OVERRIDE {
-        return SkString("imagemagnifier");
+        return SkString("imagealphathreshold");
     }
 
     virtual SkISize onISize() SK_OVERRIDE {
@@ -35,13 +34,19 @@ protected:
     }
 
     virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
+        SkIRect rects[2];
+        rects[0] = SkIRect::MakeXYWH(SkIntToScalar(0), SkIntToScalar(150),
+                                     SkIntToScalar(WIDTH),
+                                     SkIntToScalar(HEIGHT - 300));
+        rects[1] = SkIRect::MakeXYWH(SkIntToScalar(150), SkIntToScalar(0),
+                                     SkIntToScalar(WIDTH - 300),
+                                     SkIntToScalar(HEIGHT));
+        SkRegion region;
+        region.setRects(rects, 2);

[Wez, 2013/12/17 06:39:04]

So we need to plumb through the window shape through to here from the setShape()
API?

[Zachary Kuznia, 2013/12/18 00:06:27]

Yes.  I have a CL in Chromium that does this; I'll upload it next.

+
         SkPaint paint;
         paint.setImageFilter(
-            new SkMagnifierImageFilter(
-                SkRect::MakeXYWH(SkIntToScalar(100), SkIntToScalar(100),
-                                 SkIntToScalar(WIDTH / 2),
-                                 SkIntToScalar(HEIGHT / 2)),
-                100))->unref();
+            new SkAlphaThresholdFilter(region, 0, .2))->unref();
         canvas->saveLayer(NULL, &paint);
         paint.setAntiAlias(true);
         const char* str = "The quick brown fox jumped over the lazy dog.";
@@ -63,7 +68,7 @@ private:
 
 //////////////////////////////////////////////////////////////////////////////
 
-static GM* MyFactory(void*) { return new ImageMagnifierGM; }
+static GM* MyFactory(void*) { return new ImageAlphaThresholdGM; }
 static GMRegistry reg(MyFactory);
 
 }