Issue #146 - Part 1: Draw each table's background on their own display

list items.

This patch does the following things:
1. Creates nsDisplayTableBorderCollapse that draws all collapse border
of tables.
2. Stops the use of nsDisplayTableBorderBackground.
3. Lets column and column group frames generate display items.
4. When traversing the table, also traverses the column and column group
frames.
5. For each type of table frame (col group, col, row group, row and
cell), draws their own background.

1 files changed, 146 insertions, 122 deletions

diff --git a/layout/tables/nsTableFrame.cpp b/layout/tables/nsTableFrame.cpp
index 272a77406..b5cd3b487 100644
--- a/layout/tables/nsTableFrame.cpp
+++ b/layout/tables/nsTableFrame.cpp
@@ -1131,6 +1131,42 @@ nsDisplayTableItem::ComputeInvalidationRegion(nsDisplayListBuilder* aBuilder,
   nsDisplayItem::ComputeInvalidationRegion(aBuilder, aGeometry, aInvalidRegion);
 }
 
+// A display item that draws all collapsed borders for a table.
+class nsDisplayTableBorderCollapse : public nsDisplayTableItem {
+public:
+  nsDisplayTableBorderCollapse(nsDisplayListBuilder* aBuilder,
+                               nsTableFrame* aFrame)
+    : nsDisplayTableItem(aBuilder, aFrame) {
+    MOZ_COUNT_CTOR(nsDisplayTableBorderCollapse);
+    }
+#ifdef NS_BUILD_REFCNT_LOGGING
+  virtual ~nsDisplayTableBorderCollapse() {
+    MOZ_COUNT_DTOR(nsDisplayTableBorderCollapse);
+  }
+#endif
+
+  virtual void Paint(nsDisplayListBuilder* aBuilder,
+                     nsRenderingContext* aCtx) override;
+  NS_DISPLAY_DECL_NAME("TableBorderCollapse", TYPE_TABLE_BORDER_COLLAPSE)
+};
+
+void
+nsDisplayTableBorderCollapse::Paint(nsDisplayListBuilder* aBuilder,
+                                    nsRenderingContext* aCtx)
+{
+  nsPoint pt = ToReferenceFrame();
+  DrawTarget* drawTarget = aCtx->GetDrawTarget();
+
+  gfxPoint devPixelOffset =
+    nsLayoutUtils::PointToGfxPoint(pt, mFrame->PresContext()->AppUnitsPerDevPixel());
+
+  AutoRestoreTransform autoRestoreTransform(drawTarget);
+  drawTarget->SetTransform(
+      drawTarget->GetTransform().PreTranslate(ToPoint(devPixelOffset)));
+
+  static_cast<nsTableFrame*>(mFrame)->PaintBCBorders(*drawTarget, mVisibleRect - pt);
+}
+
 class nsDisplayTableBorderBackground : public nsDisplayTableItem {
 public:
   nsDisplayTableBorderBackground(nsDisplayListBuilder* aBuilder,
@@ -1150,20 +1186,6 @@ public:
   NS_DISPLAY_DECL_NAME("TableBorderBackground", TYPE_TABLE_BORDER_BACKGROUND)
 };
 
-#ifdef DEBUG
-static bool
-IsFrameAllowedInTable(nsIAtom* aType)
-{
-  return IS_TABLE_CELL(aType) ||
-         nsGkAtoms::tableRowFrame == aType ||
-         nsGkAtoms::tableRowGroupFrame == aType ||
-         nsGkAtoms::scrollFrame == aType ||
-         nsGkAtoms::tableFrame == aType ||
-         nsGkAtoms::tableColFrame == aType ||
-         nsGkAtoms::tableColGroupFrame == aType;
-}
-#endif
-
 void
 nsDisplayTableBorderBackground::Paint(nsDisplayListBuilder* aBuilder,
                                       nsRenderingContext* aCtx)
@@ -1175,25 +1197,6 @@ nsDisplayTableBorderBackground::Paint(nsDisplayListBuilder* aBuilder,
   nsDisplayTableItemGeometry::UpdateDrawResult(this, result);
 }
 
-static int32_t
-GetTablePartRank(nsDisplayItem* aItem)
-{
-  nsIAtom* type = aItem->Frame()->GetType();
-  if (type == nsGkAtoms::tableFrame)
-    return 0;
-  if (type == nsGkAtoms::tableRowGroupFrame)
-    return 1;
-  if (type == nsGkAtoms::tableRowFrame)
-    return 2;
-  return 3;
-}
-
-static bool CompareByTablePartRank(nsDisplayItem* aItem1, nsDisplayItem* aItem2,
-                                     void* aClosure)
-{
-  return GetTablePartRank(aItem1) <= GetTablePartRank(aItem2);
-}
-
 /* static */ void
 nsTableFrame::GenericTraversal(nsDisplayListBuilder* aBuilder, nsFrame* aFrame,
                                const nsRect& aDirtyRect, const nsDisplayListSet& aLists)
@@ -1206,31 +1209,73 @@ nsTableFrame::GenericTraversal(nsDisplayListBuilder* aBuilder, nsFrame* aFrame,
   // stacking context, in which case the child won't use its passed-in
   // BorderBackground list anyway. It does affect cell borders though; this
   // lets us get cell borders into the nsTableFrame's BorderBackground list.
+  for (nsIFrame* kid : aFrame->GetChildList(kColGroupList)) {
+    aFrame->BuildDisplayListForChild(aBuilder, kid, aDirtyRect, aLists);
+  }
+
   for (nsIFrame* kid : aFrame->PrincipalChildList()) {
     aFrame->BuildDisplayListForChild(aBuilder, kid, aDirtyRect, aLists);
   }
 }
 
+static void
+PaintRowBackground(nsTableRowFrame* aRow,
+                   nsIFrame* aFrame,
+                   nsDisplayListBuilder* aBuilder,
+                   const nsDisplayListSet& aLists,
+                   const nsPoint& aOffset = nsPoint())
+{
+  // Compute background rect by iterating all cell frame.
+  for (nsTableCellFrame* cell = aRow->GetFirstCell(); cell; cell = cell->GetNextCell()) {
+    auto cellRect = cell->GetRectRelativeToSelf() + cell->GetNormalPosition() + aOffset;
+    nsDisplayBackgroundImage::AppendBackgroundItemsToTop(aBuilder, aFrame, cellRect,
+                                                         aLists.BorderBackground(),
+                                                         true, nullptr,
+                                                         aFrame->GetRectRelativeToSelf());
+  }
+}
+
+static void
+PaintRowGroupBackground(nsTableRowGroupFrame* aRowGroup,
+                        nsIFrame* aFrame,
+                        nsDisplayListBuilder* aBuilder,
+                        const nsDisplayListSet& aLists)
+{
+  for (nsTableRowFrame* row = aRowGroup->GetFirstRow(); row; row = row->GetNextRow()) {
+    PaintRowBackground(row, aFrame, aBuilder, aLists, row->GetNormalPosition());
+  }
+}
+
+static void
+PaintRowGroupBackgroundByColIdx(nsTableRowGroupFrame* aRowGroup,
+                                nsIFrame* aFrame,
+                                nsDisplayListBuilder* aBuilder,
+                                const nsDisplayListSet& aLists,
+                                const nsTArray<int32_t>& aColIdx,
+                                const nsPoint& aOffset)
+{
+  for (nsTableRowFrame* row = aRowGroup->GetFirstRow(); row; row = row->GetNextRow()) {
+    for (nsTableCellFrame* cell = row->GetFirstCell(); cell; cell = cell->GetNextCell()) {
+      int32_t curColIdx;
+      cell->GetColIndex(curColIdx);
+      if (aColIdx.Contains(curColIdx)) {
+        auto cellRect = cell->GetRectRelativeToSelf() + cell->GetNormalPosition() + row->GetNormalPosition() + aOffset;
+        nsDisplayBackgroundImage::AppendBackgroundItemsToTop(aBuilder, aFrame, cellRect,
+                                                             aLists.BorderBackground(),
+                                                             true, nullptr,
+                                                             aFrame->GetRectRelativeToSelf());
+      }
+    }
+  }
+}
+
 /* static */ void
 nsTableFrame::DisplayGenericTablePart(nsDisplayListBuilder* aBuilder,
                                       nsFrame* aFrame,
                                       const nsRect& aDirtyRect,
                                       const nsDisplayListSet& aLists,
-                                      nsDisplayTableItem* aDisplayItem,
                                       DisplayGenericTablePartTraversal aTraversal)
 {
-  nsDisplayList eventsBorderBackground;
-  // If we need to sort the event backgrounds, then we'll put descendants'
-  // display items into their own set of lists.
-  bool sortEventBackgrounds = aDisplayItem && aBuilder->IsForEventDelivery();
-  nsDisplayListCollection separatedCollection;
-  const nsDisplayListSet* lists = sortEventBackgrounds ? &separatedCollection : &aLists;
-
-  nsAutoPushCurrentTableItem pushTableItem;
-  if (aDisplayItem) {
-    pushTableItem.Push(aBuilder, aDisplayItem);
-  }
-
   if (aFrame->IsVisibleForPainting(aBuilder)) {
     nsDisplayTableItem* currentItem = aBuilder->GetCurrentTableItem();
     // currentItem may be null, when none of the table parts have a
@@ -1242,72 +1287,79 @@ nsTableFrame::DisplayGenericTablePart(nsDisplayListBuilder* aBuilder,
     // Paint the outset box-shadows for the table frames
     bool hasBoxShadow = aFrame->StyleEffects()->mBoxShadow != nullptr;
     if (hasBoxShadow) {
-      lists->BorderBackground()->AppendNewToTop(
+      aLists.BorderBackground()->AppendNewToTop(
         new (aBuilder) nsDisplayBoxShadowOuter(aBuilder, aFrame));
     }
 
-    // Create dedicated background display items per-frame when we're
-    // handling events.
-    // XXX how to handle collapsed borders?
-    if (aBuilder->IsForEventDelivery()) {
+    if (aFrame->GetType() == nsGkAtoms::tableRowGroupFrame) {
+      nsTableRowGroupFrame* rowGroup = static_cast<nsTableRowGroupFrame*>(aFrame);
+      PaintRowGroupBackground(rowGroup, aFrame, aBuilder, aLists);
+    } else if (aFrame->GetType() == nsGkAtoms::tableRowFrame) {
+      nsTableRowFrame* row = static_cast<nsTableRowFrame*>(aFrame);
+      PaintRowBackground(row, aFrame, aBuilder, aLists);
+    } else if (aFrame->GetType() == nsGkAtoms::tableColGroupFrame) {
+      // Compute background rect by iterating all cell frame.
+      nsTableColGroupFrame* colGroup = static_cast<nsTableColGroupFrame*>(aFrame);
+      // Collecting column index.
+      AutoTArray<int32_t, 1> colIdx;
+      for (nsTableColFrame* col = colGroup->GetFirstColumn(); col; col = col->GetNextCol()) {
+        colIdx.AppendElement(col->GetColIndex());
+      }
+
+      nsTableFrame* table = colGroup->GetTableFrame();
+      RowGroupArray rowGroups;
+      table->OrderRowGroups(rowGroups);
+      for (nsTableRowGroupFrame* rowGroup : rowGroups) {
+        auto offset = rowGroup->GetNormalPosition() - colGroup->GetNormalPosition();
+        PaintRowGroupBackgroundByColIdx(rowGroup, aFrame, aBuilder, aLists, colIdx, offset);
+      }
+    } else if (aFrame->GetType() == nsGkAtoms::tableColFrame) {
+      // Compute background rect by iterating all cell frame.
+      nsTableColFrame* col = static_cast<nsTableColFrame*>(aFrame);
+      AutoTArray<int32_t, 1> colIdx;
+      colIdx.AppendElement(col->GetColIndex());
+
+      nsTableFrame* table = col->GetTableFrame();
+      RowGroupArray rowGroups;
+      table->OrderRowGroups(rowGroups);
+      for (nsTableRowGroupFrame* rowGroup : rowGroups) {
+        auto offset = rowGroup->GetNormalPosition() -
+                      col->GetNormalPosition() -
+                      col->GetTableColGroupFrame()->GetNormalPosition();
+        PaintRowGroupBackgroundByColIdx(rowGroup, aFrame, aBuilder, aLists, colIdx, offset);
+      }
+    } else {
       nsDisplayBackgroundImage::AppendBackgroundItemsToTop(aBuilder, aFrame,
                                                            aFrame->GetRectRelativeToSelf(),
-                                                           lists->BorderBackground());
+                                                           aLists.BorderBackground());
     }
 
     // Paint the inset box-shadows for the table frames
     if (hasBoxShadow) {
-      lists->BorderBackground()->AppendNewToTop(
+      aLists.BorderBackground()->AppendNewToTop(
         new (aBuilder) nsDisplayBoxShadowInner(aBuilder, aFrame));
     }
   }
 
-  aTraversal(aBuilder, aFrame, aDirtyRect, *lists);
+  aTraversal(aBuilder, aFrame, aDirtyRect, aLists);
 
-  if (sortEventBackgrounds) {
-    // Ensure that the table frame event background goes before the
-    // table rowgroups event backgrounds, before the table row event backgrounds,
-    // before everything else (cells and their blocks)
-    separatedCollection.BorderBackground()->Sort(CompareByTablePartRank, nullptr);
-    separatedCollection.MoveTo(aLists);
+  if (aFrame->IsVisibleForPainting(aBuilder)) {
+    if (aFrame->GetType() == nsGkAtoms::tableFrame) {
+      nsTableFrame* table = static_cast<nsTableFrame*>(aFrame);
+      // In the collapsed border model, overlay all collapsed borders.
+      if (table->IsBorderCollapse()) {
+        aLists.BorderBackground()->AppendNewToTop(
+          new (aBuilder) nsDisplayTableBorderCollapse(aBuilder, table));
+      } else {
+        aLists.BorderBackground()->AppendNewToTop(
+          new (aBuilder) nsDisplayBorder(aBuilder, table));
+      }
+    }
   }
 
   aFrame->DisplayOutline(aBuilder, aLists);
 }
 
-static bool
-AnyTablePartHasBorderOrBackground(nsIFrame* aStart, nsIFrame* aEnd)
-{
-  for (nsIFrame* f = aStart; f != aEnd; f = f->GetNextSibling()) {
-    NS_ASSERTION(IsFrameAllowedInTable(f->GetType()), "unexpected frame type");
-
-    if (FrameHasBorderOrBackground(f))
-      return true;
-
-    nsTableCellFrame *cellFrame = do_QueryFrame(f);
-    if (cellFrame)
-      continue;
-
-    if (AnyTablePartHasBorderOrBackground(f->PrincipalChildList().FirstChild(), nullptr))
-      return true;
-  }
-
-  return false;
-}
-
-static void
-UpdateItemForColGroupBackgrounds(nsDisplayTableItem* item,
-                                 const nsFrameList& aFrames) {
-  for (nsFrameList::Enumerator e(aFrames); !e.AtEnd(); e.Next()) {
-    nsTableColGroupFrame* cg = static_cast<nsTableColGroupFrame*>(e.get());
-    item->UpdateForFrameBackground(cg);
-    for (nsTableColFrame* colFrame = cg->GetFirstColumn(); colFrame;
-         colFrame = colFrame->GetNextCol()) {
-      item->UpdateForFrameBackground(colFrame);
-    }
-  }
-}
-
 // table paint code is concerned primarily with borders and bg color
 // SEC: TODO: adjust the rect for captions
 void
@@ -1317,35 +1369,7 @@ nsTableFrame::BuildDisplayList(nsDisplayListBuilder*   aBuilder,
 {
   DO_GLOBAL_REFLOW_COUNT_DSP_COLOR("nsTableFrame", NS_RGB(255,128,255));
 
-  nsDisplayTableItem* item = nullptr;
-  if (IsVisibleInSelection(aBuilder)) {
-    nsMargin deflate = GetDeflationForBackground(PresContext());
-    if (StyleVisibility()->IsVisible()) {
-      // If 'deflate' is (0,0,0,0) then we can paint the table background
-      // in its own display item, so do that to take advantage of
-      // opacity and visibility optimizations
-      if (deflate == nsMargin(0, 0, 0, 0)) {
-        DisplayBackgroundUnconditional(aBuilder, aLists, false);
-      }
-    }
-
-    // This background is created if any of the table parts are visible,
-    // or if we're doing event handling (since DisplayGenericTablePart
-    // needs the item for the |sortEventBackgrounds|-dependent code).
-    // Specific visibility decisions are delegated to the table background
-    // painter, which handles borders and backgrounds for the table.
-    if (aBuilder->IsForEventDelivery() ||
-        AnyTablePartHasBorderOrBackground(this, GetNextSibling()) ||
-        AnyTablePartHasBorderOrBackground(mColGroups.FirstChild(), nullptr)) {
-      item = new (aBuilder) nsDisplayTableBorderBackground(aBuilder, this,
-          deflate != nsMargin(0, 0, 0, 0));
-      aLists.BorderBackground()->AppendNewToTop(item);
-    }
-  }
-  DisplayGenericTablePart(aBuilder, this, aDirtyRect, aLists, item);
-  if (item) {
-    UpdateItemForColGroupBackgrounds(item, mColGroups);
-  }
+  DisplayGenericTablePart(aBuilder, this, aDirtyRect, aLists);
 }
 
 nsMargin