Bug 590468. Part 6: Fix setting of nsDisplayList::mOpaque, and return it from nsDisplayWrapList::IsOpaque. r=tnikkel

layout/base/nsDisplayList.cpp

@@ -287,9 +287,24 @@ nsDisplayList::GetBounds(nsDisplayListBuilder* aBuilder) const {
 }
 
 PRBool
-nsDisplayList::ComputeVisibility(nsDisplayListBuilder* aBuilder,
+nsDisplayList::ComputeVisibilityForRoot(nsDisplayListBuilder* aBuilder,
                                         nsRegion* aVisibleRegion) {
-  mVisibleRect = aVisibleRegion->GetBounds();
+  nsRegion r;
+  r.And(*aVisibleRegion, GetBounds(aBuilder));
+  return ComputeVisibilityForSublist(aBuilder, aVisibleRegion, r.GetBounds());
+}
+
+PRBool
+nsDisplayList::ComputeVisibilityForSublist(nsDisplayListBuilder* aBuilder,
+                                           nsRegion* aVisibleRegion,
+                                           const nsRect& aListVisibleBounds) {
+#ifdef DEBUG
+  nsRegion r;
+  r.And(*aVisibleRegion, GetBounds(aBuilder));
+  NS_ASSERTION(r.GetBounds() == aListVisibleBounds,
+               "bad aListVisibleBounds");
+#endif
+  mVisibleRect = aListVisibleBounds;
   PRBool anyVisible = PR_FALSE;
 
   nsAutoTArray<nsDisplayItem*, 512> elements;
@@ -322,7 +337,7 @@ nsDisplayList::ComputeVisibility(nsDisplayListBuilder* aBuilder,
     AppendToBottom(item);
   }
 
-  mIsOpaque = aVisibleRegion->IsEmpty();
+  mIsOpaque = !aVisibleRegion->Intersects(mVisibleRect);
 #ifdef DEBUG
   mDidComputeVisibility = PR_TRUE;
 #endif
@@ -1055,14 +1070,13 @@ nsDisplayWrapList::GetBounds(nsDisplayListBuilder* aBuilder) {
 PRBool
 nsDisplayWrapList::ComputeVisibility(nsDisplayListBuilder* aBuilder,
                                      nsRegion* aVisibleRegion) {
-  return mList.ComputeVisibility(aBuilder, aVisibleRegion);
+  return mList.ComputeVisibilityForSublist(aBuilder, aVisibleRegion,
+                                           mVisibleRect);
 }
 
 PRBool
 nsDisplayWrapList::IsOpaque(nsDisplayListBuilder* aBuilder) {
-  // We could try to do something but let's conservatively just return PR_FALSE.
+  return mList.IsOpaque();
-  // We reimplement ComputeVisibility and that's what really matters
-  return PR_FALSE;
 }
 
 PRBool nsDisplayWrapList::IsUniform(nsDisplayListBuilder* aBuilder, nscolor* aColor) {
@@ -1384,8 +1398,11 @@ PRBool nsDisplayZoom::ComputeVisibility(nsDisplayListBuilder *aBuilder,
     aVisibleRegion->ConvertAppUnitsRoundOut(mParentAPD, mAPD);
   nsRegion originalVisibleRegion = visibleRegion;
 
+  nsRect transformedVisibleRect =
+    mVisibleRect.ConvertAppUnitsRoundOut(mParentAPD, mAPD);
   PRBool retval =
-    nsDisplayWrapList::ComputeVisibility(aBuilder, &visibleRegion);
+    mList.ComputeVisibilityForSublist(aBuilder, &visibleRegion,
+                                      transformedVisibleRect);
 
   nsRegion removed;
   // removed = originalVisibleRegion - visibleRegion
@@ -1584,8 +1601,10 @@ PRBool nsDisplayTransform::ComputeVisibility(nsDisplayListBuilder *aBuilder,
    * think that it's painting in its original rectangular coordinate space. */
   nsRegion untransformedVisible =
     UntransformRect(mVisibleRect, mFrame, ToReferenceFrame());
-
+  // Call RecomputeVisiblity instead of ComputeVisibilty since
-  mStoredList.ComputeVisibility(aBuilder, &untransformedVisible);
+  // nsDisplayItem::ComputeVisibility should only be called from
+  // nsDisplayList::ComputeVisibility (which sets mVisibleRect on the item)
+  mStoredList.RecomputeVisibility(aBuilder, &untransformedVisible);
   return PR_TRUE;
 }
 
@@ -1843,7 +1862,9 @@ PRBool nsDisplaySVGEffects::ComputeVisibility(nsDisplayListBuilder* aBuilder,
   // Our children may be made translucent or arbitrarily deformed so we should
   // not allow them to subtract area from aVisibleRegion.
   nsRegion childrenVisible(dirtyRect);
-  nsDisplayWrapList::ComputeVisibility(aBuilder, &childrenVisible);
+  nsRect r;
+  r.IntersectRect(dirtyRect, mList.GetBounds(aBuilder));
+  mList.ComputeVisibilityForSublist(aBuilder, &childrenVisible, r);
   return PR_TRUE;
 }
 

layout/base/nsDisplayList.h

@@ -587,6 +587,8 @@ public:
    * nsDisplayList::ComputeVisibility will already have set mVisibleRect on
    * this item to the intersection of *aVisibleRegion (unioned with
    * *aVisibleRegionBeforeMove, if that's non-null) and this item's bounds.
+   * We rely on that, so this should only be called by
+   * nsDisplayList::ComputeVisibility or nsDisplayItem::RecomputeVisibility.
    * 
    * @return PR_TRUE if the item is visible, PR_FALSE if no part of the item
    * is visible
@@ -842,17 +844,32 @@ public:
    * This is also a good place to put ComputeVisibility-related logic
    * that must be applied to every display item. In particular, this
    * sets mVisibleRect on each display item.
-   * This also sets mIsOpaque to whether aVisibleRegion is empty on return.
+   * This sets mIsOpaque if the entire visible area of this list has
+   * been removed from aVisibleRegion when we return.
    * This does not remove any items from the list, so we can recompute
    * visiblity with different regions later (see
    * FrameLayerBuilder::DrawThebesLayer).
    * 
    * @param aVisibleRegion the area that is visible, relative to the
-   * reference frame; on return, this contains the area visible under the list
+   * reference frame; on return, this contains the area visible under the list.
+   * I.e., opaque contents of this list are subtracted from aVisibleRegion.
+   * @param aListVisibleBounds must be equal to the bounds of the intersection
+   * of aVisibleRegion and GetBounds() for this list.
    * @return true if any item in the list is visible
    */
-  PRBool ComputeVisibility(nsDisplayListBuilder* aBuilder,
+  PRBool ComputeVisibilityForSublist(nsDisplayListBuilder* aBuilder,
+                                     nsRegion* aVisibleRegion,
+                                     const nsRect& aListVisibleBounds);
+
+  /**
+   * As ComputeVisibilityForSublist, but computes visibility for a root
+   * list (a list that does not belong to an nsDisplayItem).
+   *
+   * @param aVisibleRegion the area that is visible
+   */
+  PRBool ComputeVisibilityForRoot(nsDisplayListBuilder* aBuilder,
                                   nsRegion* aVisibleRegion);
+
   /**
    * Returns true if the visible region output from ComputeVisiblity was
    * empty, i.e. everything visible in this list is opaque.

layout/base/nsLayoutDebugger.cpp

@@ -176,13 +176,13 @@ PrintDisplayListTo(nsDisplayListBuilder* aBuilder, const nsDisplayList& aList,
     }
     nscolor color;
     nsRect vis = i->GetVisibleRect();
+    nsDisplayList* list = i->GetList();
     fprintf(aOutput, "%s %p(%s) (%d,%d,%d,%d)(%d,%d,%d,%d)%s%s\n",
             i->Name(), (void*)f, NS_ConvertUTF16toUTF8(fName).get(),
             rect.x, rect.y, rect.width, rect.height,
             vis.x, vis.y, vis.width, vis.height,
-            i->IsOpaque(aBuilder) ? " opaque" : "",
+            ((!list || list->DidComputeVisibility()) && i->IsOpaque(aBuilder)) ? " opaque" : "",
             i->IsUniform(aBuilder, &color) ? " uniform" : "");
-    nsDisplayList* list = i->GetList();
     if (list) {
       PrintDisplayListTo(aBuilder, *list, aIndent + 4, aOutput);
     }

layout/base/nsLayoutUtils.cpp

@@ -1377,7 +1377,7 @@ nsLayoutUtils::PaintFrame(nsIRenderingContext* aRenderingContext, nsIFrame* aFra
   }
 #endif
 
-  list.ComputeVisibility(&builder, &visibleRegion);
+  list.ComputeVisibilityForRoot(&builder, &visibleRegion);
 
 #ifdef DEBUG
   if (gDumpPaintList) {

layout/base/nsPresContext.cpp

@@ -2536,7 +2536,7 @@ nsRootPresContext::GetPluginGeometryUpdates(nsIFrame* aChangedSubtree,
 #endif
 
     nsRegion visibleRegion(bounds);
-    list.ComputeVisibility(&builder, &visibleRegion);
+    list.ComputeVisibilityForRoot(&builder, &visibleRegion);
 
 #ifdef DEBUG
     if (gDumpPluginList) {

layout/base/nsPresShell.cpp

@@ -5618,7 +5618,7 @@ PresShell::PaintRangePaintInfo(nsTArray<nsAutoPtr<RangePaintInfo> >* aItems,
 
     aArea.MoveBy(-rangeInfo->mRootOffset.x, -rangeInfo->mRootOffset.y);
     nsRegion visible(aArea);
-    rangeInfo->mList.ComputeVisibility(&rangeInfo->mBuilder, &visible);
+    rangeInfo->mList.ComputeVisibilityForRoot(&rangeInfo->mBuilder, &visible);
     rangeInfo->mList.PaintRoot(&rangeInfo->mBuilder, rc, nsDisplayList::PAINT_DEFAULT);
     aArea.MoveBy(rangeInfo->mRootOffset.x, rangeInfo->mRootOffset.y);
   }

layout/generic/nsGfxScrollFrame.cpp

@@ -1568,7 +1568,7 @@ InvalidateFixedBackgroundFrames(nsIFrame* aRootFrame,
     return;
 
   nsRegion visibleRegion(aUpdateRect);
-  list.ComputeVisibility(&builder, &visibleRegion);
+  list.ComputeVisibilityForRoot(&builder, &visibleRegion);
 
   InvalidateFixedBackgroundFramesFromList(&builder, aMovingFrame, list);
   list.DeleteAll();

layout/generic/nsPageContentFrame.cpp

@@ -149,6 +149,8 @@ nsPageContentFrame::Reflow(nsPresContext*           aPresContext,
     aDesiredSize.height = aReflowState.availableHeight;
   }
 
+  FinishAndStoreOverflow(&aDesiredSize);
+
   NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aDesiredSize);
   return NS_OK;
 }