Modifications to DisplayList for better Slimming Paint

Source/platform/graphics/GraphicsContextTest.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *     notice, this list of conditions and the following disclaimer in the
@@ skipping 1135 matching lines @@
     EXPECT_EQ(context.getCTM(), controlContext.getCTM());
 
     controlContext.restore();
     context.endRecording();
     EXPECT_EQ(context.getCTM(), controlContext.getCTM());
 
     controlContext.restore();
     context.endRecording();
     EXPECT_EQ(context.getCTM(), controlContext.getCTM());
 }
 

[chrishtr, 2014/09/05 18:28:13]

Add a test with clips or transforms?

[Stephen Chennney, 2014/09/05 18:36:19]

Can do, but not trivial because you can't inspect the contents of an SkPicture
or canvas. We need to generate a canvas, paint something, then examine pixels.
Tests for that do exist so I can copy the basic approach, but not quickly.

I should say, non-trivial to do a meaningful test. It's easy to test the getters
and setters but I would rather do it all in one go.

OK if I punt on it for now? I'll think some more about testing next week. It's
an open issue with the Skia team.

[chrishtr, 2014/09/05 18:40:58]

Ok. For now we can test that clips & transforms are correct in layout tests.
Please add a FIXME though.

-TEST(GraphicsContextTest, DisplayList)
+TEST(GraphicsContextTest, RecordingCanvas)
 {
+    SkBitmap bitmap;
+    ASSERT_TRUE(bitmap.allocN32Pixels(1, 1));
+    bitmap.eraseColor(0);
+    SkCanvas canvas(bitmap);
+    GraphicsContext context(&canvas);
+
     FloatRect rect(0, 0, 1, 1);
-    RefPtr<DisplayList> dl = adoptRef(new DisplayList(rect));
-
-    // picture() returns 0 initially
-    SkPicture* pic = dl->picture();
-    EXPECT_FALSE(pic);
-
-    // endRecording without a beginRecording does nothing
-    dl->endRecording();
-    pic = dl->picture();
-    EXPECT_FALSE(pic);
 
     // Two beginRecordings in a row generate two canvases.
     // Unfortunately the new one could be allocated in the same
     // spot as the old one so ref the first one to prolong its life.
-    IntSize size(1, 1);
-    SkCanvas* canvas1 = dl->beginRecording(size);
+    context.beginRecording(rect);
+    SkCanvas* canvas1 = context.canvas();
     EXPECT_TRUE(canvas1);
-    canvas1->ref();
-    SkCanvas* canvas2 = dl->beginRecording(size);
+    context.beginRecording(rect);
+    SkCanvas* canvas2 = context.canvas();
     EXPECT_TRUE(canvas2);
 
     EXPECT_NE(canvas1, canvas2);
     EXPECT_EQ(1, canvas1->getRefCnt());
-    canvas1->unref();
-
-    EXPECT_TRUE(dl->isRecording());
-
-    // picture() returns 0 during recording
-    pic = dl->picture();
-    EXPECT_FALSE(pic);
 
     // endRecording finally makes the picture accessible
-    dl->endRecording();
-    pic = dl->picture();
+    RefPtr<DisplayList> dl = context.endRecording();
+    SkPicture* pic = dl->picture();
     EXPECT_TRUE(pic);
     EXPECT_EQ(1, pic->getRefCnt());
+
+    context.endRecording();
 }
 
 } // namespace