Fix saveLayer() with a pixel-moving filter vs SkBBoxHierarchyRecord / SkRecordDraw

In SkBBoxHierarchyRecord:
  Since the bounds we pass to saveLayer are in the pre-filtering
  coordinate space, they aren't correct for determining the actual
  device pixels touched by the saveLayer in this case.

  The easiest fix for now is to pass the clip bounds, since the final
  draw done in restore() will never draw outside the clip.

In SkRecordDraw:
  We do adjust the bounds passed to saveLayer, so we just need to make
  sure that when we're using a paint that may affect transparent black,
  we ignore the calculated bounds of draw ops and use the clip intersected
  with those adjusted bounds.

See originally crrev.com/497773002

BUG=skia:
R=reed@google.com, senorblanco@chromium.org, junov@chromium.org, mtklein@google.com

Author: mtklein@chromium.org

Review URL: https://codereview.chromium.org/496963003

1 files changed, 48 insertions, 0 deletions

diff --git a/tests/ImageFilterTest.cpp b/tests/ImageFilterTest.cpp
index 214aed950c..f87f99ce98 100644
--- a/tests/ImageFilterTest.cpp
+++ b/tests/ImageFilterTest.cpp
@@ -421,6 +421,54 @@ DEF_TEST(ImageFilterDrawTiled, reporter) {
     }
 }
 
+static void drawSaveLayerPicture(int width, int height, int tileSize, SkBBHFactory* factory, SkBitmap* result) {
+
+    SkMatrix matrix;
+    matrix.setTranslate(SkIntToScalar(50), 0);
+
+    SkAutoTUnref<SkColorFilter> cf(SkColorFilter::CreateModeFilter(SK_ColorWHITE, SkXfermode::kSrc_Mode));
+    SkAutoTUnref<SkImageFilter> cfif(SkColorFilterImageFilter::Create(cf.get()));
+    SkAutoTUnref<SkImageFilter> imageFilter(SkMatrixImageFilter::Create(matrix, SkPaint::kNone_FilterLevel, cfif.get()));
+
+    SkPaint paint;
+    paint.setImageFilter(imageFilter.get());
+    SkPictureRecorder recorder;
+    SkRect bounds = SkRect::Make(SkIRect::MakeXYWH(0, 0, 50, 50));
+    SkCanvas* recordingCanvas = recorder.beginRecording(width, height, factory, 0);
+    recordingCanvas->translate(-55, 0);
+    recordingCanvas->saveLayer(&bounds, &paint);
+    recordingCanvas->restore();
+    SkAutoTUnref<SkPicture> picture1(recorder.endRecording());
+
+    result->allocN32Pixels(width, height);
+    SkCanvas canvas(*result);
+    canvas.clear(0);
+    canvas.clipRect(SkRect::Make(SkIRect::MakeWH(tileSize, tileSize)));
+    canvas.drawPicture(picture1.get());
+}
+
+DEF_TEST(ImageFilterDrawMatrixBBH, reporter) {
+    // Check that matrix filter when drawn tiled with BBH exactly
+    // matches the same thing drawn without BBH.
+    // Tests pass by not asserting.
+
+    const int width = 200, height = 200;
+    const int tileSize = 100;
+    SkBitmap result1, result2;
+    SkRTreeFactory factory;
+
+    drawSaveLayerPicture(width, height, tileSize, &factory, &result1);
+    drawSaveLayerPicture(width, height, tileSize, NULL, &result2);
+
+    for (int y = 0; y < height; y++) {
+        int diffs = memcmp(result1.getAddr32(0, y), result2.getAddr32(0, y), result1.rowBytes());
+        REPORTER_ASSERT(reporter, !diffs);
+        if (diffs) {
+            break;
+        }
+    }
+}
+
 static void drawBlurredRect(SkCanvas* canvas) {
     SkAutoTUnref<SkImageFilter> filter(SkBlurImageFilter::Create(SkIntToScalar(8), 0));
     SkPaint filterPaint;