Make sure pictures draw Clears even when the clip is empty.

We fix this by rewriting empty queries to very tiny queries, which will certainly
hit ops that span the entire picture (like Clear) and hopefully not much more.

(This doesn't quite work in the full cull rect world if [0,0,ε,ε] doesn't
overlap the picture.  Let's cross that bridge when we get there.)

BUG=432991

Review URL: https://codereview.chromium.org/732723004

1 files changed, 34 insertions, 1 deletions

diff --git a/tests/PictureBBHTest.cpp b/tests/PictureBBHTest.cpp
index 3ff5625686..fa02437432 100644
--- a/tests/PictureBBHTest.cpp
+++ b/tests/PictureBBHTest.cpp
@@ -49,7 +49,9 @@ private:
         SkCanvas playbackCanvas(fResultBitmap);
         playbackCanvas.clear(SK_ColorGREEN);
         SkPictureRecorder recorder;
-        SkCanvas* recordCanvas = recorder.beginRecording(SkIntToScalar(fPictureWidth), SkIntToScalar(fPictureHeight), factory);
+        SkCanvas* recordCanvas = recorder.beginRecording(SkIntToScalar(fPictureWidth),
+                                                         SkIntToScalar(fPictureHeight),
+                                                         factory);
         this->doTest(playbackCanvas, *recordCanvas);
         SkAutoTUnref<SkPicture> picture(recorder.endRecording());
         playbackCanvas.drawPicture(picture);
@@ -99,3 +101,34 @@ DEF_TEST(PictureBBH, reporter) {
     EmptyClipPictureBBHTest emptyClipPictureTest;
     emptyClipPictureTest.run(reporter);
 }
+
+static void test_clear(skiatest::Reporter* r, SkBBHFactory* factory) {
+    // SkPicture should always call clear()s on the target canvas, even if its clip is empty.
+    SkPictureRecorder src, dst;
+
+    // A picture that's just clear().
+    src.beginRecording(1,1, factory)
+        ->clear(SK_ColorGREEN);
+    SkAutoTDelete<SkPicture> srcPic(src.endRecording());
+
+    // A target canvas with an empty clip.
+    SkCanvas* c = dst.beginRecording(1,1, NULL);
+        c->clipRect(SkRect::MakeEmpty());
+        srcPic->playback(c);
+    SkAutoTDelete<SkPicture> dstPic(dst.endRecording());
+
+    // Should be Clip - Save - Clear - Restore.
+    // Buggy implementations might return 1 (just Clip) or 3 (Clip - Save - Restore).
+    REPORTER_ASSERT(r, dstPic->approximateOpCount() == 4);
+}
+
+DEF_TEST(PictureBBH_Clear, r) {
+    test_clear(r, NULL);
+
+    SkTileGridFactory::TileGridInfo grid = { {1,1}, {0,0}, {0,0} };
+    SkTileGridFactory tilegrid(grid);
+    test_clear(r, &tilegrid);
+
+    SkRTreeFactory rtree;
+    test_clear(r, &rtree);
+}