Table cell background painting

third_party/WebKit/Source/core/layout/LayoutTableCol.cpp

 /*
  * Copyright (C) 1997 Martin Jones (mjones@kde.org)
  *           (C) 1997 Torben Weis (weis@kde.org)
  *           (C) 1998 Waldo Bastian (bastian@kde.org)
  *           (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 92 matching lines @@
 
 bool LayoutTableCol::canHaveChildren() const
 {
     // Cols cannot have children. This is actually necessary to fix a bug
     // with libraries.uc.edu, which makes a <p> be a table-column.
     return isTableColumnGroup();
 }
 
 LayoutRect LayoutTableCol::clippedOverflowRectForPaintInvalidation(const LayoutBoxModelObject* paintInvalidationContainer, const PaintInvalidationState* paintInvalidationState) const
 {
-    // For now, just paint invalidate the whole table.
-    // FIXME: Find a better way to do this, e.g., need to paint invalidate all the cells that we
-    // might have propagated a background color or borders into.
-    // FIXME: check for paintInvalidationContainer each time here?
+    // Entire table gets invalidated, instead of invalidating
+    // every cell in the column.
+    // This is simpler, but suboptimal.
 
-    LayoutTable* parentTable = table();
-    if (!parentTable)
+    LayoutTable* table = this->table();
+    if (!table)
         return LayoutRect();
-    return parentTable->clippedOverflowRectForPaintInvalidation(paintInvalidationContainer, paintInvalidationState);
+
+    // The correctness of this method depends on the fact that LayoutTableCol's
+    // location is always zero.
+    ASSERT(this->location() == LayoutPoint());
+
+    LayoutRect r = table->visualOverflowRect();
+    mapToVisibleRectInAncestorSpace(paintInvalidationContainer, r, paintInvalidationState);
+    return r;
 }
 
 void LayoutTableCol::imageChanged(WrappedImagePtr, const IntRect*)
 {
     // FIXME: Issue paint invalidation of only the rect the image paints in.
     setShouldDoFullPaintInvalidation();
 }
 
 void LayoutTableCol::clearPreferredLogicalWidthsDirtyBits()
 {
@@ skipping 56 matching lines @@
     return style()->borderStart();
 }
 
 const BorderValue& LayoutTableCol::borderAdjoiningCellAfter(const LayoutTableCell* cell) const
 {
     ASSERT_UNUSED(cell, table()->colElementAtAbsoluteColumn(cell->absoluteColumnIndex() - 1).innermostColOrColGroup() == this);
     return style()->borderEnd();
 }
 
 } // namespace blink