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);
+    LayoutRect r = table->visualOverflowRect();
+    r.setLocation(LayoutPoint(0, 0));

[Xianzhu, 2016/03/15 17:24:39]

The correctness of this method depends on the fact that LayoutTableCol is not
laid out to have an offset from the table (this is why I asked you to add the
test). Please add
   // The correctness of this method depends on the fact that LayoutTableCol's
   // location is always zero.
   ASSERT(this->location() == LayoutPoint());

[Xianzhu, 2016/03/15 17:24:39]

The above line should be removed. visualOverflowRect is in space of the object.
Normally its location is zero, but if the object has visual overflow, the
location will be negative and should be counted in the mapped result.

[atotic1, 2016/03/15 18:50:50]

Done.

[atotic1, 2016/03/15 18:50:51]

Done.

+    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