optimization/fix: dirty the clip-bounds when we mod the clip in savelayer

Before the fix, we could use a stale cache of the clipbounds in quickReject. Often this could return false negatives, meaning we would try to draw more than we should (it would eventually be really clipped). Occasionally this could also report false positives (if the layer were outside of the normal canvas bounds, e.g. a layer with an offset imagefilter).

BUG=skia:
NOTREECHECKS=True

Review URL: https://codereview.chromium.org/983243003

diff --git a/src/core/SkCanvas.cpp b/src/core/SkCanvas.cpp
index e4c03f3e5e0857464e52a43be2fa1518854d6e25..55b3b7ba7a7987ec878e82692eb94fc94cf98506 100644 (file)
--- a/src/core/SkCanvas.cpp
+++ b/src/core/SkCanvas.cpp
@@ -831,7 +831,7 @@ static bool bounds_affects_clip(SkCanvas::SaveFlags flags) {
 }
 
 bool SkCanvas::clipRectBounds(const SkRect* bounds, SaveFlags flags,
-                               SkIRect* intersection, const SkImageFilter* imageFilter) {
+                              SkIRect* intersection, const SkImageFilter* imageFilter) {
     SkIRect clipBounds;
     SkRegion::Op op = SkRegion::kIntersect_Op;
     if (!this->getClipDeviceBounds(&clipBounds)) {
@@ -854,6 +854,7 @@ bool SkCanvas::clipRectBounds(const SkRect* bounds, SaveFlags flags,
         // early exit if the layer's bounds are clipped out
         if (!ir.intersect(clipBounds)) {
             if (bounds_affects_clip(flags)) {
+                fCachedLocalClipBoundsDirty = true;
                 fMCRec->fRasterClip.setEmpty();
             }
             return false;
@@ -863,6 +864,7 @@ bool SkCanvas::clipRectBounds(const SkRect* bounds, SaveFlags flags,
     }
 
     if (bounds_affects_clip(flags)) {
+        fCachedLocalClipBoundsDirty = true;
         fClipStack->clipDevRect(ir, op);
         // early exit if the clip is now empty
         if (!fMCRec->fRasterClip.op(ir, op)) {

diff --git a/tests/QuickRejectTest.cpp b/tests/QuickRejectTest.cpp
index cefde1235452442507604a7c1a9e0cc60ed7451d..447d81615b624cd29a07933fc5fb9ec3a6e6e0e4 100644 (file)
--- a/tests/QuickRejectTest.cpp
+++ b/tests/QuickRejectTest.cpp
@@ -87,6 +87,23 @@ static void test_drawBitmap(skiatest::Reporter* reporter) {
     REPORTER_ASSERT(reporter, 0xFFFFFFFF == *dst.getAddr32(5, 5));
 }
 
+static void test_layers(skiatest::Reporter* reporter) {
+    SkCanvas canvas(100, 100);
+
+    SkRect r = SkRect::MakeWH(10, 10);
+    REPORTER_ASSERT(reporter, false == canvas.quickReject(r));
+
+    r.offset(300, 300);
+    REPORTER_ASSERT(reporter, true == canvas.quickReject(r));
+
+    // Test that saveLayer updates quickReject
+    SkRect bounds = SkRect::MakeLTRB(50, 50, 70, 70);
+    canvas.saveLayer(&bounds, NULL);
+    REPORTER_ASSERT(reporter, true == canvas.quickReject(SkRect::MakeWH(10, 10)));
+    REPORTER_ASSERT(reporter, false == canvas.quickReject(SkRect::MakeWH(60, 60)));
+}
+
 DEF_TEST(QuickReject, reporter) {
     test_drawBitmap(reporter);
+    test_layers(reporter);
 }