Add AlphaThreshold filter.

gm/imagealphathreshold.cpp

 /*
- * 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
 #define HEIGHT 500
 
 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 {
         return make_isize(WIDTH, HEIGHT);
     }
 
     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.";
         SkRandom rand;
         for (int i = 0; i < 25; ++i) {
             int x = rand.nextULessThan(WIDTH);
             int y = rand.nextULessThan(HEIGHT);
             paint.setColor(rand.nextBits(24) | 0xFF000000);
             paint.setTextSize(rand.nextRangeScalar(0, 300));
             canvas->drawText(str, strlen(str), SkIntToScalar(x),
                              SkIntToScalar(y), paint);
         }
         canvas->restore();
     }
 
 private:
     typedef GM INHERITED;
 };
 
 //////////////////////////////////////////////////////////////////////////////
 
-static GM* MyFactory(void*) { return new ImageMagnifierGM; }
+static GM* MyFactory(void*) { return new ImageAlphaThresholdGM; }
 static GMRegistry reg(MyFactory);
 
 }