Offset repeating theads correctly when two tables adjoin at a page border

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

 // Copyright 2014 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/TableSectionPainter.h"
 
 #include "core/layout/LayoutTableCell.h"
 #include "core/layout/LayoutTableCol.h"
 #include "core/layout/LayoutTableRow.h"
 #include "core/paint/BoxClipper.h"
@@ skipping 27 matching lines @@
 void TableSectionPainter::paintRepeatingHeaderGroup(const PaintInfo& paintInfo, const LayoutPoint& paintOffset, const CollapsedBorderValue& currentBorderValue, ItemToPaint itemToPaint)
 {
     if (!m_layoutTableSection.hasRepeatingHeaderGroup())
         return;
 
     LayoutTable* table = m_layoutTableSection.table();
     LayoutPoint paginationOffset = paintOffset;
     LayoutUnit pageHeight = table->pageLogicalHeightForOffset(LayoutUnit());
 
     // Move paginationOffset to the top of the next page.
-    LayoutUnit offsetToNextPage = pageHeight - intMod(table->pageLogicalOffset(), pageHeight);
+    // The header may have a pagination strut before it so we need to account for that when establishing its position.
+    LayoutUnit headerGroupOffset = table->pageLogicalOffset();
+    if (LayoutTableRow* row = m_layoutTableSection.firstRow())
+        headerGroupOffset += m_layoutTableSection.paginationStrutForRow(row, table->pageLogicalOffset());
+    LayoutUnit offsetToNextPage = pageHeight - intMod(headerGroupOffset, pageHeight);
     paginationOffset.move(0, offsetToNextPage);
     // Now move paginationOffset to the top of the page the cull rect starts on.
     if (paintInfo.cullRect().m_rect.y() > paginationOffset.y())
         paginationOffset.move(0, pageHeight * static_cast<int>((paintInfo.cullRect().m_rect.y() - paginationOffset.y()) / pageHeight));
     LayoutUnit bottomBound = std::min(LayoutUnit(paintInfo.cullRect().m_rect.maxY()), paintOffset.y() + table->logicalHeight());
     while (paginationOffset.y() < bottomBound) {
         LayoutPoint nestedOffset = paginationOffset + LayoutPoint(0, m_layoutTableSection.offsetForRepeatingHeader());
         if (itemToPaint == PaintCollapsedBorders)
             paintCollapsedSectionBorders(paintInfo, nestedOffset, currentBorderValue);
         else
@@ skipping 237 matching lines @@
     DisplayItem::Type type = shadowStyle == Normal ? DisplayItem::TableSectionBoxShadowNormal : DisplayItem::TableSectionBoxShadowInset;
     if (LayoutObjectDrawingRecorder::useCachedDrawingIfPossible(paintInfo.context, m_layoutTableSection, type))
         return;
 
     LayoutRect bounds = BoxPainter(m_layoutTableSection).boundsForDrawingRecorder(paintOffset);
     LayoutObjectDrawingRecorder recorder(paintInfo.context, m_layoutTableSection, type, bounds);
     BoxPainter::paintBoxShadow(paintInfo, LayoutRect(paintOffset, m_layoutTableSection.size()), m_layoutTableSection.styleRef(), shadowStyle);
 }
 
 } // namespace blink