gecko/layout/tables/nsTablePainter.cpp
2011-04-19 15:07:23 +12:00

680 lines
25 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is TableBackgroundPainter implementation.
*
* The Initial Developer of the Original Code is
* Elika J. Etemad ("fantasai") <fantasai@inkedblade.net>.
* Portions created by the Initial Developer are Copyright (C) 2004
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#include "nsTableFrame.h"
#include "nsTableRowGroupFrame.h"
#include "nsTableRowFrame.h"
#include "nsTableColGroupFrame.h"
#include "nsTableColFrame.h"
#include "nsTableCellFrame.h"
#include "nsTablePainter.h"
#include "nsCSSRendering.h"
#include "nsDisplayList.h"
/* ~*~ Table Background Painting ~*~
Mozilla's Table Background painting follows CSS2.1:17.5.1
That section does not, however, describe the effect of
borders on background image positioning. What we do is:
- in separate borders, the borders are passed in so that
their width figures in image positioning, even for rows/cols, which
don't have visible borders. This is done to allow authors
to position row backgrounds by, for example, aligning the
top left corner with the top left padding corner of the
top left table cell in the row in cases where all cells
have consistent border widths. If we didn't honor these
invisible borders, there would be no way to align
backgrounds with the padding edges, and designs would be
lost underneath the border.
- in collapsing borders, because the borders collapse, we
use the -continuous border- width to synthesize a border
style and pass that in instead of using the element's
assigned style directly.
The continuous border on a given edge of an element is
the collapse of all borders guaranteed to be continuous
along that edge. Cell borders are ignored (because, for
example, setting a thick border on the leftmost cell
should not shift the row background over; this way a
striped background set on <tr> will line up across rows
even if the cells are assigned arbitrary border widths.
For example, the continuous border on the top edge of a
row group is the collapse of any row group, row, and
table borders involved. (The first row group's top would
be [table-top + row group top + first row top]. It's bottom
would be [row group bottom + last row bottom + next row
top + next row group top].)
The top edge of a column group likewise includes the
table top, row group top, and first row top borders. However,
it *also* includes its own top border, since that is guaranteed
to be continuous. It does not include column borders because
those are not guaranteed to be continuous: there may be two
columns with different borders in a single column group.
An alternative would be to define the continuous border as
[table? + row group + row] for horizontal
[table? + col group + col] for vertical
This makes it easier to line up backgrounds across elements
despite varying border widths, but it does not give much
flexibility in aligning /to/ those border widths.
*/
/* ~*~ TableBackgroundPainter ~*~
The TableBackgroundPainter is created and destroyed in one painting call.
Its principal function is PaintTable, which paints all table element
backgrounds. The initial code in that method sets up an array of column
data that caches the background styles and the border sizes for the
columns and colgroups in TableBackgroundData structs in mCols. Data for
BC borders are calculated and stashed in a synthesized border style struct
in the data struct since collapsed borders aren't the same width as style-
assigned borders. The data struct optimizes by only doing this if there's
an image background; otherwise we don't care. //XXX should also check background-origin
The class then loops through the row groups, rows, and cells. It uses
the mRowGroup and mRow TableBackgroundData structs to cache data for
the current frame in the loop. At the cell level, it paints the backgrounds,
one over the other, inside the cell rect.
The exception to this pattern is when a table element creates a (pseudo)
stacking context. Elements with stacking contexts (e.g., 'opacity' applied)
are <dfn>passed through</dfn>, which means their data (and their
descendants' data) are not cached. The full loop is still executed, however,
so that underlying layers can get painted at the cell level.
The TableBackgroundPainter is then destroyed.
Elements with stacking contexts set up their own painter to finish the
painting process, since they were skipped. They call the appropriate
sub-part of the loop (e.g. PaintRow) which will paint the frame and
descendants. Note that it is permissible according to CSS2.1 to ignore'
'position:relative' (and implicitly, 'opacity') on table parts so that
table parts can never create stacking contexts; if we want to, we can
implement that, and then we won't have to deal with TableBackgroundPainter
being used anywhere but from the nsTableFrame.
XXX views are going
*/
TableBackgroundPainter::TableBackgroundData::TableBackgroundData()
: mFrame(nsnull),
mVisible(PR_FALSE),
mBorder(nsnull),
mSynthBorder(nsnull)
{
MOZ_COUNT_CTOR(TableBackgroundData);
}
TableBackgroundPainter::TableBackgroundData::~TableBackgroundData()
{
NS_ASSERTION(!mSynthBorder, "must call Destroy before dtor");
MOZ_COUNT_DTOR(TableBackgroundData);
}
void
TableBackgroundPainter::TableBackgroundData::Destroy(nsPresContext* aPresContext)
{
NS_PRECONDITION(aPresContext, "null prescontext");
if (mSynthBorder) {
mSynthBorder->Destroy(aPresContext);
mSynthBorder = nsnull;
}
}
void
TableBackgroundPainter::TableBackgroundData::Clear()
{
mRect.SetEmpty();
mFrame = nsnull;
mBorder = nsnull;
mVisible = PR_FALSE;
}
void
TableBackgroundPainter::TableBackgroundData::SetFrame(nsIFrame* aFrame)
{
NS_PRECONDITION(aFrame, "null frame");
mFrame = aFrame;
mRect = aFrame->GetRect();
}
void
TableBackgroundPainter::TableBackgroundData::SetData()
{
NS_PRECONDITION(mFrame, "null frame");
if (mFrame->IsVisibleForPainting()) {
mVisible = PR_TRUE;
mBorder = mFrame->GetStyleBorder();
}
}
void
TableBackgroundPainter::TableBackgroundData::SetFull(nsIFrame* aFrame)
{
NS_PRECONDITION(aFrame, "null frame");
SetFrame(aFrame);
SetData();
}
inline PRBool
TableBackgroundPainter::TableBackgroundData::ShouldSetBCBorder()
{
/* we only need accurate border data when positioning background images*/
if (!mVisible) {
return PR_FALSE;
}
const nsStyleBackground *bg = mFrame->GetStyleBackground();
NS_FOR_VISIBLE_BACKGROUND_LAYERS_BACK_TO_FRONT(i, bg) {
if (!bg->mLayers[i].mImage.IsEmpty())
return PR_TRUE;
}
return PR_FALSE;
}
nsresult
TableBackgroundPainter::TableBackgroundData::SetBCBorder(nsMargin& aBorder,
TableBackgroundPainter* aPainter)
{
NS_PRECONDITION(aPainter, "null painter");
if (!mSynthBorder) {
mSynthBorder = new (aPainter->mPresContext)
nsStyleBorder(aPainter->mZeroBorder);
if (!mSynthBorder) return NS_ERROR_OUT_OF_MEMORY;
}
NS_FOR_CSS_SIDES(side) {
mSynthBorder->SetBorderWidth(side, aBorder.Side(side));
}
mBorder = mSynthBorder;
return NS_OK;
}
TableBackgroundPainter::TableBackgroundPainter(nsTableFrame* aTableFrame,
Origin aOrigin,
nsPresContext* aPresContext,
nsRenderingContext& aRenderingContext,
const nsRect& aDirtyRect,
const nsPoint& aRenderPt,
PRUint32 aBGPaintFlags)
: mPresContext(aPresContext),
mRenderingContext(aRenderingContext),
mRenderPt(aRenderPt),
mDirtyRect(aDirtyRect),
mOrigin(aOrigin),
mCols(nsnull),
mZeroBorder(aPresContext),
mBGPaintFlags(aBGPaintFlags)
{
MOZ_COUNT_CTOR(TableBackgroundPainter);
NS_FOR_CSS_SIDES(side) {
mZeroBorder.SetBorderStyle(side, NS_STYLE_BORDER_STYLE_SOLID);
mZeroBorder.SetBorderWidth(side, 0);
}
mIsBorderCollapse = aTableFrame->IsBorderCollapse();
#ifdef DEBUG
mCompatMode = mPresContext->CompatibilityMode();
#endif
mNumCols = aTableFrame->GetColCount();
}
TableBackgroundPainter::~TableBackgroundPainter()
{
if (mCols) {
TableBackgroundData* lastColGroup = nsnull;
for (PRUint32 i = 0; i < mNumCols; i++) {
if (mCols[i].mColGroup != lastColGroup) {
lastColGroup = mCols[i].mColGroup;
NS_ASSERTION(mCols[i].mColGroup, "colgroup data should not be null - bug 237421");
// we need to wallpaper a over zero pointer deref, bug 237421 will have the real fix
if(lastColGroup)
lastColGroup->Destroy(mPresContext);
delete lastColGroup;
}
mCols[i].mColGroup = nsnull;
mCols[i].mCol.Destroy(mPresContext);
}
delete [] mCols;
}
mRowGroup.Destroy(mPresContext);
mRow.Destroy(mPresContext);
MOZ_COUNT_DTOR(TableBackgroundPainter);
}
nsresult
TableBackgroundPainter::PaintTableFrame(nsTableFrame* aTableFrame,
nsTableRowGroupFrame* aFirstRowGroup,
nsTableRowGroupFrame* aLastRowGroup,
const nsMargin& aDeflate)
{
NS_PRECONDITION(aTableFrame, "null frame");
TableBackgroundData tableData;
tableData.SetFull(aTableFrame);
tableData.mRect.MoveTo(0,0); //using table's coords
tableData.mRect.Deflate(aDeflate);
if (mIsBorderCollapse && tableData.ShouldSetBCBorder()) {
if (aFirstRowGroup && aLastRowGroup && mNumCols > 0) {
//only handle non-degenerate tables; we need a more robust BC model
//to make degenerate tables' borders reasonable to deal with
nsMargin border, tempBorder;
nsTableColFrame* colFrame = aTableFrame->GetColFrame(mNumCols - 1);
if (colFrame) {
colFrame->GetContinuousBCBorderWidth(tempBorder);
}
border.right = tempBorder.right;
aLastRowGroup->GetContinuousBCBorderWidth(tempBorder);
border.bottom = tempBorder.bottom;
nsTableRowFrame* rowFrame = aFirstRowGroup->GetFirstRow();
if (rowFrame) {
rowFrame->GetContinuousBCBorderWidth(tempBorder);
border.top = tempBorder.top;
}
border.left = aTableFrame->GetContinuousLeftBCBorderWidth();
nsresult rv = tableData.SetBCBorder(border, this);
if (NS_FAILED(rv)) {
tableData.Destroy(mPresContext);
return rv;
}
}
}
if (tableData.IsVisible()) {
nsCSSRendering::PaintBackgroundWithSC(mPresContext, mRenderingContext,
tableData.mFrame, mDirtyRect,
tableData.mRect + mRenderPt,
tableData.mFrame->GetStyleContext(),
*tableData.mBorder,
mBGPaintFlags);
}
tableData.Destroy(mPresContext);
return NS_OK;
}
void
TableBackgroundPainter::TranslateContext(nscoord aDX,
nscoord aDY)
{
mRenderPt += nsPoint(aDX, aDY);
if (mCols) {
TableBackgroundData* lastColGroup = nsnull;
for (PRUint32 i = 0; i < mNumCols; i++) {
mCols[i].mCol.mRect.MoveBy(-aDX, -aDY);
if (lastColGroup != mCols[i].mColGroup) {
NS_ASSERTION(mCols[i].mColGroup, "colgroup data should not be null - bug 237421");
// we need to wallpaper a over zero pointer deref, bug 237421 will have the real fix
if (!mCols[i].mColGroup)
return;
mCols[i].mColGroup->mRect.MoveBy(-aDX, -aDY);
lastColGroup = mCols[i].mColGroup;
}
}
}
}
nsresult
TableBackgroundPainter::PaintTable(nsTableFrame* aTableFrame,
const nsMargin& aDeflate,
PRBool aPaintTableBackground)
{
NS_PRECONDITION(aTableFrame, "null table frame");
nsTableFrame::RowGroupArray rowGroups;
aTableFrame->OrderRowGroups(rowGroups);
if (rowGroups.Length() < 1) { //degenerate case
if (aPaintTableBackground) {
PaintTableFrame(aTableFrame, nsnull, nsnull, nsMargin(0,0,0,0));
}
/* No cells; nothing else to paint */
return NS_OK;
}
if (aPaintTableBackground) {
PaintTableFrame(aTableFrame, rowGroups[0], rowGroups[rowGroups.Length() - 1],
aDeflate);
}
/*Set up column background/border data*/
if (mNumCols > 0) {
nsFrameList& colGroupList = aTableFrame->GetColGroups();
NS_ASSERTION(colGroupList.FirstChild(), "table should have at least one colgroup");
mCols = new ColData[mNumCols];
if (!mCols) return NS_ERROR_OUT_OF_MEMORY;
TableBackgroundData* cgData = nsnull;
nsMargin border;
/* BC left borders aren't stored on cols, but the previous column's
right border is the next one's left border.*/
//Start with table's left border.
nscoord lastLeftBorder = aTableFrame->GetContinuousLeftBCBorderWidth();
for (nsTableColGroupFrame* cgFrame = static_cast<nsTableColGroupFrame*>(colGroupList.FirstChild());
cgFrame; cgFrame = static_cast<nsTableColGroupFrame*>(cgFrame->GetNextSibling())) {
if (cgFrame->GetColCount() < 1) {
//No columns, no cells, so no need for data
continue;
}
/*Create data struct for column group*/
cgData = new TableBackgroundData;
if (!cgData) return NS_ERROR_OUT_OF_MEMORY;
cgData->SetFull(cgFrame);
if (mIsBorderCollapse && cgData->ShouldSetBCBorder()) {
border.left = lastLeftBorder;
cgFrame->GetContinuousBCBorderWidth(border);
nsresult rv = cgData->SetBCBorder(border, this);
if (NS_FAILED(rv)) {
cgData->Destroy(mPresContext);
delete cgData;
return rv;
}
}
// Boolean that indicates whether mCols took ownership of cgData
PRBool cgDataOwnershipTaken = PR_FALSE;
/*Loop over columns in this colgroup*/
for (nsTableColFrame* col = cgFrame->GetFirstColumn(); col;
col = static_cast<nsTableColFrame*>(col->GetNextSibling())) {
/*Create data struct for column*/
PRUint32 colIndex = col->GetColIndex();
NS_ASSERTION(colIndex < mNumCols, "prevent array boundary violation");
if (mNumCols <= colIndex)
break;
mCols[colIndex].mCol.SetFull(col);
//Bring column mRect into table's coord system
mCols[colIndex].mCol.mRect.MoveBy(cgData->mRect.x, cgData->mRect.y);
//link to parent colgroup's data
mCols[colIndex].mColGroup = cgData;
cgDataOwnershipTaken = PR_TRUE;
if (mIsBorderCollapse) {
border.left = lastLeftBorder;
lastLeftBorder = col->GetContinuousBCBorderWidth(border);
if (mCols[colIndex].mCol.ShouldSetBCBorder()) {
nsresult rv = mCols[colIndex].mCol.SetBCBorder(border, this);
if (NS_FAILED(rv)) return rv;
}
}
}
if (!cgDataOwnershipTaken) {
cgData->Destroy(mPresContext);
delete cgData;
}
}
}
for (PRUint32 i = 0; i < rowGroups.Length(); i++) {
nsTableRowGroupFrame* rg = rowGroups[i];
mRowGroup.SetFrame(rg);
// Need to compute the right rect via GetOffsetTo, since the row
// group may not be a child of the table.
mRowGroup.mRect.MoveTo(rg->GetOffsetTo(aTableFrame));
if (mRowGroup.mRect.Intersects(mDirtyRect - mRenderPt)) {
nsresult rv = PaintRowGroup(rg, rg->IsPseudoStackingContextFromStyle());
if (NS_FAILED(rv)) return rv;
}
}
return NS_OK;
}
nsresult
TableBackgroundPainter::PaintRowGroup(nsTableRowGroupFrame* aFrame,
PRBool aPassThrough)
{
NS_PRECONDITION(aFrame, "null frame");
if (!mRowGroup.mFrame) {
mRowGroup.SetFrame(aFrame);
}
nsTableRowFrame* firstRow = aFrame->GetFirstRow();
/* Load row group data */
if (!aPassThrough) {
mRowGroup.SetData();
if (mIsBorderCollapse && mRowGroup.ShouldSetBCBorder()) {
nsMargin border;
if (firstRow) {
//pick up first row's top border (= rg top border)
firstRow->GetContinuousBCBorderWidth(border);
/* (row group doesn't store its top border) */
}
//overwrite sides+bottom borders with rg's own
aFrame->GetContinuousBCBorderWidth(border);
nsresult res = mRowGroup.SetBCBorder(border, this);
if (!NS_SUCCEEDED(res)) {
return res;
}
}
aPassThrough = !mRowGroup.IsVisible();
}
/* translate everything into row group coord system*/
if (eOrigin_TableRowGroup != mOrigin) {
TranslateContext(mRowGroup.mRect.x, mRowGroup.mRect.y);
}
nsRect rgRect = mRowGroup.mRect;
mRowGroup.mRect.MoveTo(0, 0);
/* Find the right row to start with */
nscoord ignored; // We don't care about overflow above, since what we really
// care about are backgrounds and overflow above doesn't
// correspond to backgrounds, since cells can't span up from
// their originating row. We do care about overflow below,
// however, since that can be due to rowspans.
// Note that mDirtyRect - mRenderPt is guaranteed to be in the row
// group's coordinate system here, so passing its .y to
// GetFirstRowContaining is ok.
nsIFrame* cursor = aFrame->GetFirstRowContaining(mDirtyRect.y - mRenderPt.y, &ignored);
// Sadly, it seems like there may be non-row frames in there... or something?
// There are certainly null-checks in GetFirstRow() and GetNextRow(). :(
while (cursor && cursor->GetType() != nsGkAtoms::tableRowFrame) {
cursor = cursor->GetNextSibling();
}
// It's OK if cursor is null here.
nsTableRowFrame* row = static_cast<nsTableRowFrame*>(cursor);
if (!row) {
// No useful cursor; just start at the top. Don't bother to set up a
// cursor; if we've gotten this far then we've already built the display
// list for the rowgroup, so not having a cursor means that there's some
// good reason we don't have a cursor and we shouldn't create one here.
row = firstRow;
}
/* Finally paint */
for (; row; row = row->GetNextRow()) {
mRow.SetFrame(row);
if (mDirtyRect.YMost() - mRenderPt.y < mRow.mRect.y) { // Intersect wouldn't handle
// rowspans.
// All done; cells originating in later rows can't intersect mDirtyRect.
break;
}
nsresult rv = PaintRow(row, aPassThrough || row->IsPseudoStackingContextFromStyle());
if (NS_FAILED(rv)) return rv;
}
/* translate back into table coord system */
if (eOrigin_TableRowGroup != mOrigin) {
TranslateContext(-rgRect.x, -rgRect.y);
}
/* unload rg data */
mRowGroup.Clear();
return NS_OK;
}
nsresult
TableBackgroundPainter::PaintRow(nsTableRowFrame* aFrame,
PRBool aPassThrough)
{
NS_PRECONDITION(aFrame, "null frame");
if (!mRow.mFrame) {
mRow.SetFrame(aFrame);
}
/* Load row data */
if (!aPassThrough) {
mRow.SetData();
if (mIsBorderCollapse && mRow.ShouldSetBCBorder()) {
nsMargin border;
nsTableRowFrame* nextRow = aFrame->GetNextRow();
if (nextRow) { //outer top below us is inner bottom for us
border.bottom = nextRow->GetOuterTopContBCBorderWidth();
}
else { //acquire rg's bottom border
nsTableRowGroupFrame* rowGroup = static_cast<nsTableRowGroupFrame*>(aFrame->GetParent());
rowGroup->GetContinuousBCBorderWidth(border);
}
//get the rest of the borders; will overwrite all but bottom
aFrame->GetContinuousBCBorderWidth(border);
nsresult res = mRow.SetBCBorder(border, this);
if (!NS_SUCCEEDED(res)) {
return res;
}
}
aPassThrough = !mRow.IsVisible();
}
/* Translate */
if (eOrigin_TableRow == mOrigin) {
/* If we originate from the row, then make the row the origin. */
mRow.mRect.MoveTo(0, 0);
}
//else: Use row group's coord system -> no translation necessary
for (nsTableCellFrame* cell = aFrame->GetFirstCell(); cell; cell = cell->GetNextCell()) {
//Translate to use the same coord system as mRow.
mCellRect = cell->GetRect() + mRow.mRect.TopLeft() + mRenderPt;
if (mCellRect.Intersects(mDirtyRect)) {
nsresult rv = PaintCell(cell, aPassThrough || cell->IsPseudoStackingContextFromStyle());
if (NS_FAILED(rv)) return rv;
}
}
/* Unload row data */
mRow.Clear();
return NS_OK;
}
nsresult
TableBackgroundPainter::PaintCell(nsTableCellFrame* aCell,
PRBool aPassSelf)
{
NS_PRECONDITION(aCell, "null frame");
const nsStyleTableBorder* cellTableStyle;
cellTableStyle = aCell->GetStyleTableBorder();
if (!(NS_STYLE_TABLE_EMPTY_CELLS_SHOW == cellTableStyle->mEmptyCells ||
NS_STYLE_TABLE_EMPTY_CELLS_SHOW_BACKGROUND == cellTableStyle->mEmptyCells)
&& aCell->GetContentEmpty() && !mIsBorderCollapse) {
return NS_OK;
}
PRInt32 colIndex;
aCell->GetColIndex(colIndex);
NS_ASSERTION(colIndex < PRInt32(mNumCols), "prevent array boundary violation");
if (PRInt32(mNumCols) <= colIndex)
return NS_OK;
//Paint column group background
if (mCols && mCols[colIndex].mColGroup && mCols[colIndex].mColGroup->IsVisible()) {
nsCSSRendering::PaintBackgroundWithSC(mPresContext, mRenderingContext,
mCols[colIndex].mColGroup->mFrame, mDirtyRect,
mCols[colIndex].mColGroup->mRect + mRenderPt,
mCols[colIndex].mColGroup->mFrame->GetStyleContext(),
*mCols[colIndex].mColGroup->mBorder,
mBGPaintFlags, &mCellRect);
}
//Paint column background
if (mCols && mCols[colIndex].mCol.IsVisible()) {
nsCSSRendering::PaintBackgroundWithSC(mPresContext, mRenderingContext,
mCols[colIndex].mCol.mFrame, mDirtyRect,
mCols[colIndex].mCol.mRect + mRenderPt,
mCols[colIndex].mCol.mFrame->GetStyleContext(),
*mCols[colIndex].mCol.mBorder,
mBGPaintFlags, &mCellRect);
}
//Paint row group background
if (mRowGroup.IsVisible()) {
nsCSSRendering::PaintBackgroundWithSC(mPresContext, mRenderingContext,
mRowGroup.mFrame, mDirtyRect,
mRowGroup.mRect + mRenderPt,
mRowGroup.mFrame->GetStyleContext(),
*mRowGroup.mBorder,
mBGPaintFlags, &mCellRect);
}
//Paint row background
if (mRow.IsVisible()) {
nsCSSRendering::PaintBackgroundWithSC(mPresContext, mRenderingContext,
mRow.mFrame, mDirtyRect,
mRow.mRect + mRenderPt,
mRow.mFrame->GetStyleContext(),
*mRow.mBorder,
mBGPaintFlags, &mCellRect);
}
//Paint cell background in border-collapse unless we're just passing
if (mIsBorderCollapse && !aPassSelf) {
aCell->PaintCellBackground(mRenderingContext, mDirtyRect,
mCellRect.TopLeft(), mBGPaintFlags);
}
return NS_OK;
}