Account for border spacing correctly when repeating header groups

third_party/WebKit/Source/core/layout/LayoutTableSection.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, 2008, 2009, 2010, 2013 Apple Inc.
  *               All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  *
@@ skipping 1228 matching lines @@
   LayoutUnit pageLogicalHeight = pageLogicalHeightForOffset(logicalOffset);
   if (!pageLogicalHeight)
     return 0;
   // If the row is too tall for the page don't insert a strut.
   LayoutUnit rowLogicalHeight = row->logicalHeight();
   if (rowLogicalHeight > pageLogicalHeight)
     return 0;
 
   LayoutUnit remainingLogicalHeight = pageRemainingLogicalHeightForOffset(
       logicalOffset, LayoutBlock::AssociateWithLatterPage);
-  LayoutUnit offsetForBorderSpacing =
-      pageLogicalHeight - (remainingLogicalHeight + table()->vBorderSpacing());
-  // Border spacing from the previous row has pushed this row just past the top
-  // of the page, so we must reposition it to the top of the page and avoid any
-  // repeating header.
-  if (offsetForBorderSpacing < 0)
-    return offsetForBorderSpacing.toInt();
-
   if (remainingLogicalHeight >= rowLogicalHeight)
     return 0;  // It fits fine where it is. No need to break.
   LayoutUnit paginationStrut = calculatePaginationStrutToFitContent(
       logicalOffset, remainingLogicalHeight, rowLogicalHeight);
   if (paginationStrut == remainingLogicalHeight &&
       remainingLogicalHeight == pageLogicalHeight) {
     // Don't break if we were at the top of a page, and we failed to fit the
     // content completely. No point in leaving a page completely blank.
     return 0;
   }
@@ skipping 724 matching lines @@
   return logicalHeight;
 }
 
 void LayoutTableSection::adjustRowForPagination(LayoutTableRow& rowObject,
                                                 SubtreeLayoutScope& layouter) {
   LayoutState& state = *view()->layoutState();
   rowObject.setPaginationStrut(LayoutUnit());
   rowObject.setLogicalHeight(LayoutUnit(logicalHeightForRow(rowObject)));
   int paginationStrut =
       paginationStrutForRow(&rowObject, rowObject.logicalTop());
+  bool rowIsAtTopOfColumn = false;
+  LayoutUnit offsetFromTopOfPage;
   if (!paginationStrut) {
-    bool rowIsAtTopOfColumn =
-        state.heightOffsetForTableHeaders() &&
-        pageLogicalHeightForOffset(rowObject.logicalTop()) ==
-            pageRemainingLogicalHeightForOffset(rowObject.logicalTop(),
-                                                AssociateWithLatterPage);
+    if (state.heightOffsetForTableHeaders()) {
+      offsetFromTopOfPage =
+          pageLogicalHeightForOffset(rowObject.logicalTop()) -
+          pageRemainingLogicalHeightForOffset(rowObject.logicalTop(),
+                                              AssociateWithLatterPage);
+      rowIsAtTopOfColumn = !offsetFromTopOfPage ||
+                           offsetFromTopOfPage <= table()->vBorderSpacing();
+    }
+
     if (!rowIsAtTopOfColumn)
       return;
   }
   // We need to push this row to the next fragmentainer. If there are repeated
   // table headers, we need to make room for those at the top of the next
   // fragmentainer, above this row. Otherwise, this row will just go at the top
   // of the next fragmentainer.
 
   // If there isn't room for at least one content row on a page with a
   // header group, then we won't repeat the header on each page.
   LayoutTableSection* header = table()->header();
   if (!rowObject.rowIndex() && header &&
       table()->sectionAbove(this) == header &&
       header->getPaginationBreakability() != AllowAnyBreaks) {
     state.setHeightOffsetForTableHeaders(state.heightOffsetForTableHeaders() -
                                          header->logicalHeight());
   }
+  // Border spacing from the previous row has pushed this row just past the top
+  // of the page, so we must reposition it to the top of the page and avoid any
+  // repeating header.
+  if (rowIsAtTopOfColumn && offsetFromTopOfPage)
+    paginationStrut -= offsetFromTopOfPage.toInt();
+
   // If we have a header group we will paint it at the top of each page,
   // move the rows down to accomodate it.
   paginationStrut += state.heightOffsetForTableHeaders().toInt();
   rowObject.setPaginationStrut(LayoutUnit(paginationStrut));
 
   // We have inserted a pagination strut before the row. Adjust the logical top
   // and re-lay out. We no longer want to break inside the row, but rather
   // *before* it. From the previous layout pass, there are most likely
   // pagination struts inside some cell in this row that we need to get rid of.
   rowObject.setLogicalTop(rowObject.logicalTop() + paginationStrut);
@@ skipping 41 matching lines @@
   // the header in all columns.
   // Note that this is in flow thread coordinates, not visual coordinates. The
   // enclosing LayoutFlowThread will convert to visual coordinates.
   if (table()->header() == this && isRepeatingHeaderGroup())
     rect.setHeight(table()->logicalHeight());
   return LayoutTableBoxComponent::mapToVisualRectInAncestorSpace(ancestor, rect,
                                                                  flags);
 }
 
 }  // namespace blink