Bug 170330. Factor out overflowArea calculations and take into account overflow:hidden. Also improve calculations of clipping for invalidation in the view manager. r+sr=dbaron

layout/base/public/nsIFrame.h

@@ -794,6 +794,13 @@ public:
                                  PRInt32*                 outFrameContentOffset,
                                  nsIFrame*                *outChildFrame) = 0;
 
+  /**
+   * Returns true iff the frame has a view (i.e., GetView() returns non-null)
+   */
+  PRBool HasView() {
+    return (mState & NS_FRAME_HAS_VIEW) != 0;
+  }
+
  /**
    * Get the current frame-state value for this frame. aResult is
    * filled in with the state bits. 

layout/generic/nsBlockFrame.cpp

@@ -771,21 +771,16 @@ nsBlockFrame::Reflow(nsIPresContext*          aPresContext,
       // Whether or not we're complete hasn't changed
       aStatus = (nsnull != mNextInFlow) ? NS_FRAME_NOT_COMPLETE : NS_FRAME_COMPLETE;
       
-      // Factor the absolutely positioned child bounds into the overflow area
       ComputeCombinedArea(aReflowState, aMetrics);
+
+      // Factor the absolutely positioned child bounds into the overflow area
       nsRect childBounds;
       mAbsoluteContainer.CalculateChildBounds(aPresContext, childBounds);
       aMetrics.mOverflowArea.UnionRect(aMetrics.mOverflowArea, childBounds);
 
-      // Make sure the NS_FRAME_OUTSIDE_CHILDREN flag is set correctly
+      // Finish computing the overflow area, taking account of outline and
-      if ((aMetrics.mOverflowArea.x < 0) ||
+      // overflow:hidden etc
-          (aMetrics.mOverflowArea.y < 0) ||
+      ComputeOverflowArea(aMetrics.mOverflowArea, aMetrics.mOverflowArea);
-          (aMetrics.mOverflowArea.XMost() > aMetrics.width) ||
-          (aMetrics.mOverflowArea.YMost() > aMetrics.height)) {
-        mState |= NS_FRAME_OUTSIDE_CHILDREN;
-      } else {
-        mState &= ~NS_FRAME_OUTSIDE_CHILDREN;
-      }
 
       return NS_OK;
     }
@@ -1095,18 +1090,13 @@ nsBlockFrame::Reflow(nsIPresContext*          aPresContext,
 
     // Factor the absolutely positioned child bounds into the overflow area
     aMetrics.mOverflowArea.UnionRect(aMetrics.mOverflowArea, childBounds);
-
-    // Make sure the NS_FRAME_OUTSIDE_CHILDREN flag is set correctly
-    if ((aMetrics.mOverflowArea.x < 0) ||
-        (aMetrics.mOverflowArea.y < 0) ||
-        (aMetrics.mOverflowArea.XMost() > aMetrics.width) ||
-        (aMetrics.mOverflowArea.YMost() > aMetrics.height)) {
-      mState |= NS_FRAME_OUTSIDE_CHILDREN;
-    } else {
-      mState &= ~NS_FRAME_OUTSIDE_CHILDREN;
-    }
   }
 
+  // Area of child content has been computed into mOverflowArea
+  // Finish computing the overflow area, taking account of outline and
+  // overflow:hidden etc
+  ComputeOverflowArea(aMetrics.mOverflowArea, aMetrics.mOverflowArea);
+
   // Clear the space manager pointer in the block reflow state so we
   // don't waste time translating the coordinate system back on a dead
   // space manager.
@@ -1169,10 +1159,6 @@ nsBlockFrame::Reflow(nsIPresContext*          aPresContext,
   }
 #endif
 
-#ifdef DEBUG_roc
-      printf("*** Metrics width/height on the way out=%d,%d\n", aMetrics.width, aMetrics.height);
-#endif
-
   NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aMetrics);
   return rv;
 }
@@ -1546,18 +1532,6 @@ nsBlockFrame::ComputeFinalSize(const nsHTMLReflowState& aReflowState,
   }
 
   ComputeCombinedArea(aReflowState, aMetrics);
-
-  // If the combined area of our children exceeds our bounding box
-  // then set the NS_FRAME_OUTSIDE_CHILDREN flag, otherwise clear it.
-  if ((aMetrics.mOverflowArea.x < 0) ||
-      (aMetrics.mOverflowArea.y < 0) ||
-      (aMetrics.mOverflowArea.XMost() > aMetrics.width) ||
-      (aMetrics.mOverflowArea.YMost() > aMetrics.height)) {
-    mState |= NS_FRAME_OUTSIDE_CHILDREN;
-  }
-  else {
-    mState &= ~NS_FRAME_OUTSIDE_CHILDREN;
-  }
 }
 
 void

layout/generic/nsFrame.cpp

@@ -754,6 +754,55 @@ nsFrame::DisplaySelection(nsIPresContext* aPresContext, PRBool isOkToTurnOn)
   return selType;
 }
 
+void
+nsFrame::ComputeOverflowArea(nsRect& aOverflowArea,
+                             const nsRect& aCombinedChildren)
+{
+  // the frame's rect in its own coordinate system
+  nsRect r(0, 0, mRect.width, mRect.height);
+  // Make the default combined area: frame U children
+  aOverflowArea.UnionRect(aCombinedChildren, r);
+  // WARNING: aCombinedChildren might be the same rect as aOverflowArea.
+  // It may have been destroyed now. Don't use it below.
+
+  // Don't do the following mildly expensive stuff unless we have a view;
+  // any block frame with overflow:hidden will have a view
+  // (see nsContainerFrame::FrameNeedsView).
+  // HasView() is very cheap; it just checks a bit on mState.
+  if (HasView()) {
+    // The following code is temporarily disabled. We'll turn it on
+    // when proper support for 'outline' lands. Note that it assumes
+    // any frame with 'outline' has a view. --- roc
+#if 0
+    // Add in the outline width, which overflows our border area
+    const nsStyleOutline* outline;
+    ::GetStyleData(mStyleContext, &outline);
+    
+    nscoord width;
+    outline->GetOutlineWidth(width);
+    r.Inflate(width, width);
+#endif
+    
+    // overflow:hidden doesn't need to take account of the child area
+    const nsStyleDisplay* display;
+    ::GetStyleData(mStyleContext, &display);
+    if (NS_STYLE_OVERFLOW_HIDDEN == display->mOverflow
+        && (display->IsBlockLevel() || display->IsFloating())) {
+      aOverflowArea = r;
+    }
+  }
+
+  // Set state bit to indicate whether there is any overflow
+  if (aOverflowArea.x < 0
+      || aOverflowArea.y < 0
+      || aOverflowArea.XMost() > mRect.width
+      || aOverflowArea.YMost() > mRect.height) {
+    mState |= NS_FRAME_OUTSIDE_CHILDREN;
+  } else {
+    mState &= ~NS_FRAME_OUTSIDE_CHILDREN;
+  }
+}
+
 void
 nsFrame::SetOverflowClipRect(nsIRenderingContext& aRenderingContext)
 {

layout/generic/nsFrame.h

@@ -348,6 +348,11 @@ public:
                          const nsRect& aDamageRect,
                          PRBool aImmediate = PR_FALSE) const;
 
+  // Helper function to compute the overflow area for a frame,
+  // taking into account overflow:hidden and any outline present.
+  // This sets the frame state bit FRAME_OUTSIDE_CHILDREN if necessary.
+  void ComputeOverflowArea(nsRect& aOverflowArea, const nsRect& aCombinedChildren);
+
   // Helper function to return the index in parent of the frame's content
   // object. Returns -1 on error or if the frame doesn't have a content object
   static PRInt32 ContentIndexInContainer(const nsIFrame* aFrame);

layout/generic/nsIFrame.h

@@ -794,6 +794,13 @@ public:
                                  PRInt32*                 outFrameContentOffset,
                                  nsIFrame*                *outChildFrame) = 0;
 
+  /**
+   * Returns true iff the frame has a view (i.e., GetView() returns non-null)
+   */
+  PRBool HasView() {
+    return (mState & NS_FRAME_HAS_VIEW) != 0;
+  }
+
  /**
    * Get the current frame-state value for this frame. aResult is
    * filled in with the state bits. 

layout/generic/nsInlineFrame.cpp

@@ -1311,16 +1311,8 @@ nsPositionedInlineFrame::Reflow(nsIPresContext*          aPresContext,
       mAbsoluteContainer.CalculateChildBounds(aPresContext, childBounds);
       aDesiredSize.mOverflowArea.UnionRect(aDesiredSize.mOverflowArea, childBounds);
 
-      // Make sure the NS_FRAME_OUTSIDE_CHILDREN flag is set correctly
-      if ((aDesiredSize.mOverflowArea.x < 0) ||
-          (aDesiredSize.mOverflowArea.y < 0) ||
-          (aDesiredSize.mOverflowArea.XMost() > aDesiredSize.width) ||
-          (aDesiredSize.mOverflowArea.YMost() > aDesiredSize.height)) {
-        mState |= NS_FRAME_OUTSIDE_CHILDREN;
-      } else {
-        mState &= ~NS_FRAME_OUTSIDE_CHILDREN;
-      }
 #endif
+      // Don't update the overflow area state here. It's done by line layout.
       return rv;
     }
   }
@@ -1356,16 +1348,8 @@ nsPositionedInlineFrame::Reflow(nsIPresContext*          aPresContext,
     // Factor the absolutely positioned child bounds into the overflow area
     aDesiredSize.mOverflowArea.UnionRect(aDesiredSize.mOverflowArea, childBounds);
 
-    // Make sure the NS_FRAME_OUTSIDE_CHILDREN flag is set correctly
-    if ((aDesiredSize.mOverflowArea.x < 0) ||
-        (aDesiredSize.mOverflowArea.y < 0) ||
-        (aDesiredSize.mOverflowArea.XMost() > aDesiredSize.width) ||
-        (aDesiredSize.mOverflowArea.YMost() > aDesiredSize.height)) {
-      mState |= NS_FRAME_OUTSIDE_CHILDREN;
-    } else {
-      mState &= ~NS_FRAME_OUTSIDE_CHILDREN;
-    }
 #endif
+    // Don't update the overflow area state here. It's done by line layout.
   }
 
   return rv;

layout/generic/nsLineLayout.cpp

@@ -1258,16 +1258,11 @@ nsLineLayout::ReflowFrame(nsIFrame* aFrame,
   nsIView*  view;
   aFrame->GetView(mPresContext, &view);
   if (view) {
-    nsIViewManager  *vm;
+    nsCOMPtr<nsIViewManager> vm;
-    view->GetViewManager(vm);
+    view->GetViewManager(*getter_AddRefs(vm));
 
-#if 0 // XXX This is the correct code. We'll turn it on later to mitigate risk.
     vm->ResizeView(view, pfd->mCombinedArea);
-#else // imitate the old, wrong code
+    nsContainerFrame::SyncFrameViewAfterSizeChange(mPresContext, pfd->mFrame, nsnull, view);
-    nsRect r(0, 0, metrics.width, metrics.height);
-    vm->ResizeView(view, r);
-#endif
-    NS_RELEASE(vm);
   }
 
   // Tell the frame that we're done reflowing it
@@ -3323,20 +3318,26 @@ nsLineLayout::RelativePositionFrames(PerSpanData* psd, nsRect& aCombinedArea)
   }
 
   // If we just computed a spans combined area, we need to update its
-  // NS_FRAME_OUTSIDE_CHILDREN bit..
+  // NS_FRAME_OUTSIDE_CHILDREN bit. We also may need to take into account
+  // an outline.
   if (nsnull != psd->mFrame) {
     pfd = psd->mFrame;
     nsIFrame* frame = pfd->mFrame;
-    nsFrameState oldState;
+
-    frame->GetFrameState(&oldState);
+    // We're conservative here; the combined area for this span/frame
-    nsFrameState newState = oldState & ~NS_FRAME_OUTSIDE_CHILDREN;
+    // is the union of the area that the frame computed during reflow
-    if ((minX < 0) || (minY < 0) ||
+    // and the area that we computed for it here in RelativePositionFrames.
-        (maxX > pfd->mBounds.width) || (maxY > pfd->mBounds.height)) {
+    // We do this because relatively positioned frames that are also spans
-      newState |= NS_FRAME_OUTSIDE_CHILDREN;
+    // have two contributors to the overflow area: overflowing inline children
-    }
+    // and overflowing absolute children.
-    if (newState != oldState) {
+    // This could be larger than necessary if inline alignment caused an inline child
-      frame->SetFrameState(newState);
+    // to overflow less, because its old overflow would still be counted in 
-    }
+    // pfd->mCombinedArea.
+    // But in practice it's OK to have an overflow area that's larger than necessary.
+    // (Although if it happens too often it could become a paint performance issue).
+    nsRect children;
+    children.UnionRect(pfd->mCombinedArea, aCombinedArea);
+    NS_STATIC_CAST(nsFrame*, frame)->ComputeOverflowArea(aCombinedArea, children);
   }
 }
 

layout/html/base/src/nsBlockFrame.cpp

@@ -771,21 +771,16 @@ nsBlockFrame::Reflow(nsIPresContext*          aPresContext,
       // Whether or not we're complete hasn't changed
       aStatus = (nsnull != mNextInFlow) ? NS_FRAME_NOT_COMPLETE : NS_FRAME_COMPLETE;
       
-      // Factor the absolutely positioned child bounds into the overflow area
       ComputeCombinedArea(aReflowState, aMetrics);
+
+      // Factor the absolutely positioned child bounds into the overflow area
       nsRect childBounds;
       mAbsoluteContainer.CalculateChildBounds(aPresContext, childBounds);
       aMetrics.mOverflowArea.UnionRect(aMetrics.mOverflowArea, childBounds);
 
-      // Make sure the NS_FRAME_OUTSIDE_CHILDREN flag is set correctly
+      // Finish computing the overflow area, taking account of outline and
-      if ((aMetrics.mOverflowArea.x < 0) ||
+      // overflow:hidden etc
-          (aMetrics.mOverflowArea.y < 0) ||
+      ComputeOverflowArea(aMetrics.mOverflowArea, aMetrics.mOverflowArea);
-          (aMetrics.mOverflowArea.XMost() > aMetrics.width) ||
-          (aMetrics.mOverflowArea.YMost() > aMetrics.height)) {
-        mState |= NS_FRAME_OUTSIDE_CHILDREN;
-      } else {
-        mState &= ~NS_FRAME_OUTSIDE_CHILDREN;
-      }
 
       return NS_OK;
     }
@@ -1095,18 +1090,13 @@ nsBlockFrame::Reflow(nsIPresContext*          aPresContext,
 
     // Factor the absolutely positioned child bounds into the overflow area
     aMetrics.mOverflowArea.UnionRect(aMetrics.mOverflowArea, childBounds);
-
-    // Make sure the NS_FRAME_OUTSIDE_CHILDREN flag is set correctly
-    if ((aMetrics.mOverflowArea.x < 0) ||
-        (aMetrics.mOverflowArea.y < 0) ||
-        (aMetrics.mOverflowArea.XMost() > aMetrics.width) ||
-        (aMetrics.mOverflowArea.YMost() > aMetrics.height)) {
-      mState |= NS_FRAME_OUTSIDE_CHILDREN;
-    } else {
-      mState &= ~NS_FRAME_OUTSIDE_CHILDREN;
-    }
   }
 
+  // Area of child content has been computed into mOverflowArea
+  // Finish computing the overflow area, taking account of outline and
+  // overflow:hidden etc
+  ComputeOverflowArea(aMetrics.mOverflowArea, aMetrics.mOverflowArea);
+
   // Clear the space manager pointer in the block reflow state so we
   // don't waste time translating the coordinate system back on a dead
   // space manager.
@@ -1169,10 +1159,6 @@ nsBlockFrame::Reflow(nsIPresContext*          aPresContext,
   }
 #endif
 
-#ifdef DEBUG_roc
-      printf("*** Metrics width/height on the way out=%d,%d\n", aMetrics.width, aMetrics.height);
-#endif
-
   NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aMetrics);
   return rv;
 }
@@ -1546,18 +1532,6 @@ nsBlockFrame::ComputeFinalSize(const nsHTMLReflowState& aReflowState,
   }
 
   ComputeCombinedArea(aReflowState, aMetrics);
-
-  // If the combined area of our children exceeds our bounding box
-  // then set the NS_FRAME_OUTSIDE_CHILDREN flag, otherwise clear it.
-  if ((aMetrics.mOverflowArea.x < 0) ||
-      (aMetrics.mOverflowArea.y < 0) ||
-      (aMetrics.mOverflowArea.XMost() > aMetrics.width) ||
-      (aMetrics.mOverflowArea.YMost() > aMetrics.height)) {
-    mState |= NS_FRAME_OUTSIDE_CHILDREN;
-  }
-  else {
-    mState &= ~NS_FRAME_OUTSIDE_CHILDREN;
-  }
 }
 
 void

layout/html/base/src/nsFrame.cpp

@@ -754,6 +754,55 @@ nsFrame::DisplaySelection(nsIPresContext* aPresContext, PRBool isOkToTurnOn)
   return selType;
 }
 
+void
+nsFrame::ComputeOverflowArea(nsRect& aOverflowArea,
+                             const nsRect& aCombinedChildren)
+{
+  // the frame's rect in its own coordinate system
+  nsRect r(0, 0, mRect.width, mRect.height);
+  // Make the default combined area: frame U children
+  aOverflowArea.UnionRect(aCombinedChildren, r);
+  // WARNING: aCombinedChildren might be the same rect as aOverflowArea.
+  // It may have been destroyed now. Don't use it below.
+
+  // Don't do the following mildly expensive stuff unless we have a view;
+  // any block frame with overflow:hidden will have a view
+  // (see nsContainerFrame::FrameNeedsView).
+  // HasView() is very cheap; it just checks a bit on mState.
+  if (HasView()) {
+    // The following code is temporarily disabled. We'll turn it on
+    // when proper support for 'outline' lands. Note that it assumes
+    // any frame with 'outline' has a view. --- roc
+#if 0
+    // Add in the outline width, which overflows our border area
+    const nsStyleOutline* outline;
+    ::GetStyleData(mStyleContext, &outline);
+    
+    nscoord width;
+    outline->GetOutlineWidth(width);
+    r.Inflate(width, width);
+#endif
+    
+    // overflow:hidden doesn't need to take account of the child area
+    const nsStyleDisplay* display;
+    ::GetStyleData(mStyleContext, &display);
+    if (NS_STYLE_OVERFLOW_HIDDEN == display->mOverflow
+        && (display->IsBlockLevel() || display->IsFloating())) {
+      aOverflowArea = r;
+    }
+  }
+
+  // Set state bit to indicate whether there is any overflow
+  if (aOverflowArea.x < 0
+      || aOverflowArea.y < 0
+      || aOverflowArea.XMost() > mRect.width
+      || aOverflowArea.YMost() > mRect.height) {
+    mState |= NS_FRAME_OUTSIDE_CHILDREN;
+  } else {
+    mState &= ~NS_FRAME_OUTSIDE_CHILDREN;
+  }
+}
+
 void
 nsFrame::SetOverflowClipRect(nsIRenderingContext& aRenderingContext)
 {

layout/html/base/src/nsFrame.h

@@ -348,6 +348,11 @@ public:
                          const nsRect& aDamageRect,
                          PRBool aImmediate = PR_FALSE) const;
 
+  // Helper function to compute the overflow area for a frame,
+  // taking into account overflow:hidden and any outline present.
+  // This sets the frame state bit FRAME_OUTSIDE_CHILDREN if necessary.
+  void ComputeOverflowArea(nsRect& aOverflowArea, const nsRect& aCombinedChildren);
+
   // Helper function to return the index in parent of the frame's content
   // object. Returns -1 on error or if the frame doesn't have a content object
   static PRInt32 ContentIndexInContainer(const nsIFrame* aFrame);

layout/html/base/src/nsInlineFrame.cpp

@@ -1311,16 +1311,8 @@ nsPositionedInlineFrame::Reflow(nsIPresContext*          aPresContext,
       mAbsoluteContainer.CalculateChildBounds(aPresContext, childBounds);
       aDesiredSize.mOverflowArea.UnionRect(aDesiredSize.mOverflowArea, childBounds);
 
-      // Make sure the NS_FRAME_OUTSIDE_CHILDREN flag is set correctly
-      if ((aDesiredSize.mOverflowArea.x < 0) ||
-          (aDesiredSize.mOverflowArea.y < 0) ||
-          (aDesiredSize.mOverflowArea.XMost() > aDesiredSize.width) ||
-          (aDesiredSize.mOverflowArea.YMost() > aDesiredSize.height)) {
-        mState |= NS_FRAME_OUTSIDE_CHILDREN;
-      } else {
-        mState &= ~NS_FRAME_OUTSIDE_CHILDREN;
-      }
 #endif
+      // Don't update the overflow area state here. It's done by line layout.
       return rv;
     }
   }
@@ -1356,16 +1348,8 @@ nsPositionedInlineFrame::Reflow(nsIPresContext*          aPresContext,
     // Factor the absolutely positioned child bounds into the overflow area
     aDesiredSize.mOverflowArea.UnionRect(aDesiredSize.mOverflowArea, childBounds);
 
-    // Make sure the NS_FRAME_OUTSIDE_CHILDREN flag is set correctly
-    if ((aDesiredSize.mOverflowArea.x < 0) ||
-        (aDesiredSize.mOverflowArea.y < 0) ||
-        (aDesiredSize.mOverflowArea.XMost() > aDesiredSize.width) ||
-        (aDesiredSize.mOverflowArea.YMost() > aDesiredSize.height)) {
-      mState |= NS_FRAME_OUTSIDE_CHILDREN;
-    } else {
-      mState &= ~NS_FRAME_OUTSIDE_CHILDREN;
-    }
 #endif
+    // Don't update the overflow area state here. It's done by line layout.
   }
 
   return rv;

layout/html/base/src/nsLineLayout.cpp

@@ -1258,16 +1258,11 @@ nsLineLayout::ReflowFrame(nsIFrame* aFrame,
   nsIView*  view;
   aFrame->GetView(mPresContext, &view);
   if (view) {
-    nsIViewManager  *vm;
+    nsCOMPtr<nsIViewManager> vm;
-    view->GetViewManager(vm);
+    view->GetViewManager(*getter_AddRefs(vm));
 
-#if 0 // XXX This is the correct code. We'll turn it on later to mitigate risk.
     vm->ResizeView(view, pfd->mCombinedArea);
-#else // imitate the old, wrong code
+    nsContainerFrame::SyncFrameViewAfterSizeChange(mPresContext, pfd->mFrame, nsnull, view);
-    nsRect r(0, 0, metrics.width, metrics.height);
-    vm->ResizeView(view, r);
-#endif
-    NS_RELEASE(vm);
   }
 
   // Tell the frame that we're done reflowing it
@@ -3323,20 +3318,26 @@ nsLineLayout::RelativePositionFrames(PerSpanData* psd, nsRect& aCombinedArea)
   }
 
   // If we just computed a spans combined area, we need to update its
-  // NS_FRAME_OUTSIDE_CHILDREN bit..
+  // NS_FRAME_OUTSIDE_CHILDREN bit. We also may need to take into account
+  // an outline.
   if (nsnull != psd->mFrame) {
     pfd = psd->mFrame;
     nsIFrame* frame = pfd->mFrame;
-    nsFrameState oldState;
+
-    frame->GetFrameState(&oldState);
+    // We're conservative here; the combined area for this span/frame
-    nsFrameState newState = oldState & ~NS_FRAME_OUTSIDE_CHILDREN;
+    // is the union of the area that the frame computed during reflow
-    if ((minX < 0) || (minY < 0) ||
+    // and the area that we computed for it here in RelativePositionFrames.
-        (maxX > pfd->mBounds.width) || (maxY > pfd->mBounds.height)) {
+    // We do this because relatively positioned frames that are also spans
-      newState |= NS_FRAME_OUTSIDE_CHILDREN;
+    // have two contributors to the overflow area: overflowing inline children
-    }
+    // and overflowing absolute children.
-    if (newState != oldState) {
+    // This could be larger than necessary if inline alignment caused an inline child
-      frame->SetFrameState(newState);
+    // to overflow less, because its old overflow would still be counted in 
-    }
+    // pfd->mCombinedArea.
+    // But in practice it's OK to have an overflow area that's larger than necessary.
+    // (Although if it happens too often it could become a paint performance issue).
+    nsRect children;
+    children.UnionRect(pfd->mCombinedArea, aCombinedArea);
+    NS_STATIC_CAST(nsFrame*, frame)->ComputeOverflowArea(aCombinedArea, children);
   }
 }
 

view/public/nsIViewManager.h

@@ -547,6 +547,9 @@ public:
 
 };
 
+//update view as if a child view was being invalidated,
+//so the view should apply its 'child clip'
+#define NS_VMREFRESH_FORCHILD           0x0001
 //update view now?
 #define NS_VMREFRESH_IMMEDIATE          0x0002
 //prevent "sync painting"

view/src/nsViewManager.cpp

@@ -1629,12 +1629,18 @@ NS_IMETHODIMP nsViewManager::UpdateView(nsIView *aView, const nsRect &aRect, PRU
   }
   view->ConvertFromParentCoords(&clippedRect.x, &clippedRect.y);
 
+  if ((aUpdateFlags & NS_VMREFRESH_FORCHILD) != 0 && view->GetClipChildren()) {
+    nsRect childClipRect;
+    view->GetChildClip(childClipRect);
+    if (!clippedRect.IntersectRect(clippedRect, childClipRect)) {
+      return NS_OK;
+    }
+  }
+
   nsRect damagedRect;
-  damagedRect.x = aRect.x;
+  if (!damagedRect.IntersectRect(aRect, clippedRect)) {
-  damagedRect.y = aRect.y;
+    return NS_OK;
-  damagedRect.width = aRect.width;
+  }
-  damagedRect.height = aRect.height;
-  damagedRect.IntersectRect(aRect, clippedRect);
 
    // If the rectangle is not visible then abort
    // without invalidating. This is a performance 
@@ -2500,10 +2506,10 @@ NS_IMETHODIMP nsViewManager::MoveViewTo(nsIView *aView, nscoord aX, nscoord aY)
     view->GetVisibility(visibility);
     if (visibility != nsViewVisibility_kHide) {
       nsView* parentView = view->GetParent();
-      UpdateView(parentView, oldArea, NS_VMREFRESH_NO_SYNC);
+      UpdateView(parentView, oldArea, NS_VMREFRESH_NO_SYNC | NS_VMREFRESH_FORCHILD);
       nsRect newArea;
       view->GetBounds(newArea);
-      UpdateView(parentView, newArea, NS_VMREFRESH_NO_SYNC);
+      UpdateView(parentView, newArea, NS_VMREFRESH_NO_SYNC | NS_VMREFRESH_FORCHILD);
     }
   }
   return NS_OK;
@@ -2564,7 +2570,7 @@ NS_IMETHODIMP nsViewManager::ResizeView(nsIView *aView, const nsRect &aRect, PRB
 
         UpdateView(view, aRect, NS_VMREFRESH_NO_SYNC);
         view->ConvertToParentCoords(&oldDimensions.x, &oldDimensions.y);
-        UpdateView(parentView, oldDimensions, NS_VMREFRESH_NO_SYNC);
+        UpdateView(parentView, oldDimensions, NS_VMREFRESH_NO_SYNC | NS_VMREFRESH_FORCHILD);
       } else {
         view->SetDimensions(aRect, PR_FALSE);
 
@@ -2572,7 +2578,7 @@ NS_IMETHODIMP nsViewManager::ResizeView(nsIView *aView, const nsRect &aRect, PRB
         nsRect r = aRect;
         view->ConvertToParentCoords(&r.x, &r.y);
         view->ConvertToParentCoords(&oldDimensions.x, &oldDimensions.y);
-        InvalidateRectDifference(parentView, oldDimensions, r, NS_VMREFRESH_NO_SYNC);
+        InvalidateRectDifference(parentView, oldDimensions, r, NS_VMREFRESH_NO_SYNC | NS_VMREFRESH_FORCHILD);
       } 
     }
 
@@ -2650,7 +2656,8 @@ NS_IMETHODIMP nsViewManager::SetViewChildClipRegion(nsIView *aView, const nsRegi
     if (parent != nsnull) {
       view->ConvertToParentCoords(&oldClipRect.x, &oldClipRect.y);
       view->ConvertToParentCoords(&newClipRect.x, &newClipRect.y);
-      InvalidateRectDifference(parent, oldClipRect, newClipRect, NS_VMREFRESH_NO_SYNC);
+      InvalidateRectDifference(parent, oldClipRect, newClipRect,
+                               NS_VMREFRESH_NO_SYNC | NS_VMREFRESH_FORCHILD);
     }
   }
 
@@ -2887,7 +2894,7 @@ NS_IMETHODIMP nsViewManager::SetViewVisibility(nsIView *aView, nsViewVisibility
           if (parentView) {
             nsRect  bounds;
             view->GetBounds(bounds);
-            UpdateView(parentView, bounds, NS_VMREFRESH_NO_SYNC);
+            UpdateView(parentView, bounds, NS_VMREFRESH_NO_SYNC | NS_VMREFRESH_FORCHILD);
           }
         }
         else {