test dont-clip-layer

gm/aaclip.cpp

Index: gm/aaclip.cpp
diff --git a/gm/aaclip.cpp b/gm/aaclip.cpp
index 1cb71577990ba75759a5c72c42db5ec42d4eb9b3..adc776fe680120f6bbd56d09aca3b4701b77e1f0 100644
--- a/gm/aaclip.cpp
+++ b/gm/aaclip.cpp
@@ -9,6 +9,27 @@
 #include "SkCanvas.h"
 #include "SkPath.h"
 
+static void do_draw(SkCanvas* canvas, const SkRect& r) {
+    SkPaint paint;
+    paint.setXfermodeMode(SkXfermode::kSrc_Mode);
+    paint.setColor(0x800000FF);
+    canvas->drawRect(r, paint);
+}
+
+DEF_SIMPLE_GM(dont_clip_to_layer, canvas, 350, 120) {

[mtklein, 2016/09/06 14:05:19]

were there going to be 2 more horizontally?

[reed1, 2016/09/06 14:36:32]

The scrolling code in android sometimes does that: it creates two layers with a
"hole" in the middle. However that was harder to diagnose than this simpler
example, which exercises all of the needed code paths (and showed the bug on GPU
before the fix).

[mtklein, 2016/09/06 14:51:21]

Sorry, was just wondering about why this was so wide.  It can probably be
120x120 right?

[reed1, 2016/09/06 15:06:29]

Ah, gotcha. Will fix.

+    SkRect r { 10, 10, 110, 110 };
+    SkRect r0 = SkRect::MakeXYWH(r.left(), r.top(), r.width(), r.height()/2);
+
+    SkCanvas::SaveLayerRec rec;
+    rec.fPaint = nullptr;
+    rec.fBounds = &r0;
+    rec.fBackdrop = nullptr;
+    rec.fSaveLayerFlags = 1 << 31;//SkCanvas::kDontClipToLayer_Legacy_SaveLayerFlag;
+    canvas->saveLayer(rec);

[mtklein, 2016/09/06 14:05:19]

Can you add a comment about the effect that we're testing here?  (I think if you
put it above the DEF_SIMPLE_GM, Joe's comments harvester will pick it up.)  I
don't understand why the two halves of the square end up with the colors they
do.

[reed1, 2016/09/06 14:36:32]

Done.

+    do_draw(canvas, r);
+    canvas->restore();
+}
+
 /** Draw a 2px border around the target, then red behind the target;
     set the clip to match the target, then draw >> the target in blue.
 */