Repeat footers in paginated context

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 76 matching lines @@
 }
 
 LayoutTableSection::LayoutTableSection(Element* element)
     : LayoutTableBoxComponent(element),
       c_col_(0),
       c_row_(0),
       needs_cell_recalc_(false),
       force_full_paint_(false),
       has_multiple_cell_levels_(false),
       has_spanning_cells_(false),
-      is_repeating_header_group_(false) {
+      is_repeating_header_group_(false),
+      is_repeating_footer_group_(false) {
   // init LayoutObject attributes
   SetInline(false);  // our object is not Inline
 }
 
 LayoutTableSection::~LayoutTableSection() {}
 
 void LayoutTableSection::StyleDidChange(StyleDifference diff,
                                         const ComputedStyle* old_style) {
   DCHECK(Style()->Display() == EDisplay::kTableFooterGroup ||
          Style()->Display() == EDisplay::kTableRowGroup ||
@@ skipping 1100 matching lines @@
   DCHECK(!NeedsLayout());
 
   SetLogicalHeight(LayoutUnit(row_pos_[total_rows]));
 
   ComputeOverflowFromDescendants();
 }
 
 int LayoutTableSection::PaginationStrutForRow(LayoutTableRow* row,
                                               LayoutUnit logical_offset) const {
   DCHECK(row);
-  if (row->GetPaginationBreakability() == kAllowAnyBreaks)
+  const LayoutTableSection* footer = Table()->Footer();
+  bool make_room_for_repeating_footer =
+      footer && footer->IsRepeatingFooterGroup() && row->RowIndex();
+  if (!make_room_for_repeating_footer &&
+      row->GetPaginationBreakability() == kAllowAnyBreaks)
     return 0;
   if (!IsPageLogicalHeightKnown())
     return 0;
   LayoutUnit page_logical_height = PageLogicalHeightForOffset(logical_offset);
   // If the row is too tall for the page don't insert a strut.
   LayoutUnit row_logical_height = row->LogicalHeight();
-  if (row_logical_height > page_logical_height)
+  if (row_logical_height > page_logical_height) {

[mstensho (USE GERRIT), 2017/06/16 08:43:06]

No need for the curls.

[rhogan, 2017/06/20 18:46:05]

OK.

     return 0;
+  }
+
+  LayoutState* layout_state = View()->GetLayoutState();

[mstensho (USE GERRIT), 2017/06/16 08:43:06]

Please move it inside the "if (make_room_for_repeating_footer)" block. Might as
well do View()->GetLayoutState()->HeightOffsetForTableFooters() directly there,
unless the code formatter is going to turn that into soup.

[rhogan, 2017/06/20 18:46:05]

Sure.

+  if (make_room_for_repeating_footer)
+    row_logical_height += layout_state->HeightOffsetForTableFooters();
 
   LayoutUnit remaining_logical_height = PageRemainingLogicalHeightForOffset(
       logical_offset, LayoutBlock::kAssociateWithLatterPage);
   if (remaining_logical_height >= row_logical_height)
     return 0;  // It fits fine where it is. No need to break.
   LayoutUnit pagination_strut = CalculatePaginationStrutToFitContent(
       logical_offset, remaining_logical_height, row_logical_height);
   if (pagination_strut == remaining_logical_height &&
       remaining_logical_height == page_logical_height) {
     // Don't break if we were at the top of a page, and we failed to fit the
@@ skipping 701 matching lines @@
   // pagination struts inside some cell in this row that we need to get rid of.
   row_object.SetLogicalTop(row_object.LogicalTop() + pagination_strut);
   layouter.SetChildNeedsLayout(&row_object);
   row_object.LayoutIfNeeded();
 
   // It's very likely that re-laying out (and nuking pagination struts inside
   // cells) gave us a new height.
   row_object.SetLogicalHeight(LayoutUnit(LogicalHeightForRow(row_object)));
 }
 
-bool LayoutTableSection::HeaderGroupShouldRepeat() const {
-  if (Table()->Header() != this)
+bool LayoutTableSection::GroupShouldRepeat() const {
+  if (GetPaginationBreakability() == kAllowAnyBreaks)

[mstensho (USE GERRIT), 2017/06/16 08:43:06]

I wonder if you should add a DCHECK at the beginning of this method, to document
that we only expect headers and footers here.

[rhogan, 2017/06/20 18:46:06]

Done.

     return false;
 
-  if (GetPaginationBreakability() == kAllowAnyBreaks)
-    return false;
   // TODO(rhogan): Sections can be self-painting.
   if (HasSelfPaintingLayer())
     return false;
+
   // If we don't know the page height yet, just assume we fit.
   if (!IsPageLogicalHeightKnown())
     return true;
   LayoutUnit page_height = PageLogicalHeightForOffset(LayoutUnit());
 
   if (LogicalHeight() > page_height)
     return false;
 
   // See https://drafts.csswg.org/css-tables-3/#repeated-headers which says
   // a header/footer can repeat if it takes up less than a quarter of the page.
   if (LogicalHeight() > 0 && page_height / LogicalHeight() < 4)
     return false;
 
   return true;
 }
 
+bool LayoutTableSection::HeaderGroupShouldRepeat() const {
+  if (Table()->Header() != this)
+    return false;
+  return GroupShouldRepeat();
+}
+
+bool LayoutTableSection::FooterGroupShouldRepeat() const {
+  if (Table()->Footer() != this)
+    return false;
+  return GroupShouldRepeat();
+}
+
 bool LayoutTableSection::MapToVisualRectInAncestorSpaceInternal(
     const LayoutBoxModelObject* ancestor,
     TransformState& transform_state,
     VisualRectFlags flags) const {
   if (ancestor == this)
     return true;
-  // Repeating table headers are painted once per fragmentation page/column.
+  // Repeating table headers and footers are painted once per fragmentation

[mstensho (USE GERRIT), 2017/06/16 08:43:06]

Instead of "fragmentation page/column", I suggest "fragmentainer" or
"page/column".

[rhogan, 2017/06/20 18:46:05]

Indeed.

+  // page/column. So we need to use the rect for the entire table because
+  // the repeating headers/footers will appear throughout it.
   // This does not go through the regular fragmentation machinery, so we need
   // special code to expand the invalidation rect to contain all positions of
   // 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 (IsRepeatingHeaderGroup()) {
+  if (IsRepeatingHeaderGroup() || IsRepeatingFooterGroup()) {
     transform_state.Flatten();
     FloatRect rect = transform_state.LastPlanarQuad().BoundingBox();
     rect.SetHeight(Table()->LogicalHeight());
     transform_state.SetQuad(FloatQuad(rect));
+    return Table()->MapToVisualRectInAncestorSpaceInternal(
+        ancestor, transform_state, flags);

[rhogan, 2017/06/20 18:46:06]

This is the place which used to trigger the DCHECK I removed above. Pretty sure
it's safe to remove now.

[mstensho (USE GERRIT), 2017/06/20 21:39:05]

I see no DCHECK removed.

   }
   return LayoutTableBoxComponent::MapToVisualRectInAncestorSpaceInternal(
       ancestor, transform_state, flags);
 }
 
 bool LayoutTableSection::PaintedOutputOfObjectHasNoEffectRegardlessOfSize()
     const {
   // LayoutTableSection paints background from columns.
   if (Table()->HasColElements())
     return false;
   return LayoutTableBoxComponent::
       PaintedOutputOfObjectHasNoEffectRegardlessOfSize();
 }
 
 }  // namespace blink