Repeat footers in paginated context

third_party/WebKit/Source/core/paint/CollapsedBorderPainter.cpp

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/paint/CollapsedBorderPainter.h"
 
 #include "core/paint/BlockPainter.h"
 #include "core/paint/ObjectPainter.h"
 #include "core/paint/PaintInfo.h"
 
@@ skipping 68 matching lines @@
         cell_preceding->RowSpan() >= cell_.RowSpan()) {
       start_.value = nullptr;
       // Otherwise we'll still paint the shared border twice which may cause
       // incorrect border conflict resolution for row/col spanning cells.
       // TODO(crbug.com/2902 etc.): Paint collapsed borders by grid cells.
     }
   }
 
   // Skip painting the before border if it will be painted by the above cell
   // as its after border. If we break page before the row with non-zero strut
-  // (which means a gap between this row and the row above), we need to paint
-  // the before border separately.
+  // (which means a gap between this row and the row above), or if we are
+  // painting the top row of a footer that repeats on each page we need to paint
+  // the before border separately. This will double-paint the top border of the

[mstensho (USE GERRIT), 2017/07/17 10:38:08]

That double-painting doesn't seem like a good thing to do? Maybe add some paint
team reviewer.

[rhogan, 2017/07/24 18:56:07]

Will do. wangxianzhu would be ideal but he's off for a while. I think the double
painting is unavoidable for now due to the new way we paint collapsed borders.

[mstensho (USE GERRIT), 2017/07/25 08:59:32]

OK. A TODO, then.

+  // footer on the last page.
   if (before_.value && !cell_.Row()->PaginationStrut()) {
     const auto* cell_above = table_.CellAbove(cell_);
+    bool cell_is_top_of_repeating_footer =

[mstensho (USE GERRIT), 2017/07/17 10:38:08]

Sounds like a rare case, and a lot of other conditions need to be true before we
even need to evaluate this. Maybe move the check inside the following if-body.

[rhogan, 2017/07/24 18:56:07]

Done.

+        cell_.Section()->IsRepeatingFooterGroup() &&
+        (!cell_above || cell_above->Section() != cell_.Section());
     if (cell_.StartsAtSameColumn(cell_above) &&
         cell_above->ColSpan() >= cell_.ColSpan() &&
-        cell_above->Row()->HasSameDirectionAs(&table_)) {
+        cell_above->Row()->HasSameDirectionAs(&table_) &&
+        !cell_is_top_of_repeating_footer) {
       before_.value = nullptr;
       // Otherwise we'll still paint the shared border twice which may cause
       // incorrect border conflict resolution for row/col spanning cells.
       // TODO(crbug.com/2902 etc.): Paint collapsed borders by grid cells.
     }
   }
 }
 
 static const CollapsedBorderValues* GetCollapsedBorderValues(
     const LayoutTableCell* cell) {
@@ skipping 265 matching lines @@
   if (end_.value) {
     ObjectPainter::DrawLineForBoxSide(
         context, rect.MaxX() - end_.inner_width, rect.Y() - end_.begin_outset,
         rect.MaxX() + end_.outer_width, rect.MaxY() + end_.end_outset, kBSRight,
         end_.value->GetColor(), CollapsedBorderStyle(end_.value->Style()), 0, 0,
         true);
   }
 }
 
 }  // namespace blink