pjs/layout/tables/FixedTableLayoutStrategy.cpp

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
// vim:cindent:ts=4:et:sw=4:
/* ***** 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 Mozilla's table layout code.
*
* The Initial Developer of the Original Code is the Mozilla Foundation.
* Portions created by the Initial Developer are Copyright (C) 2006
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* L. David Baron <dbaron@dbaron.org> (original author)
*
* 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 ***** */
/*
* Algorithms that determine column and table widths used for CSS2's
* 'table-layout: fixed'.
*/
#include "FixedTableLayoutStrategy.h"
#include "nsTableFrame.h"
#include "nsTableColFrame.h"
#include "nsTableCellFrame.h"
FixedTableLayoutStrategy::FixedTableLayoutStrategy(nsTableFrame *aTableFrame)
: mTableFrame(aTableFrame)
{
MarkIntrinsicWidthsDirty();
}
/* virtual */
FixedTableLayoutStrategy::~FixedTableLayoutStrategy()
{
}
/* virtual */ nscoord
FixedTableLayoutStrategy::GetMinWidth(nsIRenderingContext* aRenderingContext)
{
DISPLAY_MIN_WIDTH(mTableFrame, mMinWidth);
if (mMinWidth != NS_INTRINSIC_WIDTH_UNKNOWN)
return mMinWidth;
// It's theoretically possible to do something much better here that
// depends only on the columns and the first row, but it wouldn't be
// compatible with other browsers, or with the use of GetMinWidth by
// nsHTMLReflowState to determine the width of a fixed-layout table,
// since CSS2.1 says:
// The width of the table is then the greater of the value of the
// 'width' property for the table element and the sum of the
// column widths (plus cell spacing or borders).
// XXX Should we really ignore 'min-width' and 'max-width'?
nsTableCellMap *cellMap = mTableFrame->GetCellMap();
PRInt32 colCount = cellMap->GetColCount();
nscoord spacing = mTableFrame->GetCellSpacingX();
// XXX Should this code do any pixel rounding?
nscoord result = 0;
// XXX Consider widths on columns or column groups?
if (colCount > 0) {
// XXX Should only add columns that have cells originating in them!
result += spacing * (colCount + 1);
}
for (PRInt32 col = 0; col < colCount; ++col) {
nsTableColFrame *colFrame = mTableFrame->GetColFrame(col);
if (!colFrame) {
NS_ERROR("column frames out of sync with cell map");
continue;
}
const nsStyleCoord *styleWidth =
&colFrame->GetStylePosition()->mWidth;
if (styleWidth->GetUnit() == eStyleUnit_Coord) {
result += nsLayoutUtils::ComputeWidthValue(aRenderingContext,
colFrame, 0, 0, 0, *styleWidth);
} else if (styleWidth->GetUnit() == eStyleUnit_Percent) {
// do nothing
} else {
NS_ASSERTION(styleWidth->GetUnit() == eStyleUnit_Auto ||
styleWidth->GetUnit() == eStyleUnit_Enumerated,
"bad width");
// The 'table-layout: fixed' algorithm considers only cells
// in the first row.
PRBool originates;
PRInt32 colSpan;
nsTableCellFrame *cellFrame =
cellMap->GetCellInfoAt(0, col, &originates, &colSpan);
if (cellFrame) {
styleWidth = &cellFrame->GetStylePosition()->mWidth;
if (styleWidth->GetUnit() == eStyleUnit_Coord ||
(styleWidth->GetUnit() == eStyleUnit_Enumerated &&
(styleWidth->GetIntValue() == NS_STYLE_WIDTH_MAX_CONTENT ||
styleWidth->GetIntValue() == NS_STYLE_WIDTH_MIN_CONTENT))) {
nscoord cellWidth = nsLayoutUtils::IntrinsicForContainer(
aRenderingContext, cellFrame, nsLayoutUtils::MIN_WIDTH);
if (colSpan > 1) {
// If a column-spanning cell is in the first
// row, split up the space evenly. (XXX This
// isn't quite right if some of the columns it's
// in have specified widths. Should we care?)
cellWidth = ((cellWidth + spacing) / colSpan) - spacing;
}
result += cellWidth;
} else if (styleWidth->GetUnit() == eStyleUnit_Percent) {
if (colSpan > 1) {
// XXX Can this force columns to negative
// widths?
result -= spacing * (colSpan - 1);
}
}
// else, for 'auto', '-moz-available', and '-moz-fit-content'
// do nothing
}
}
}
return (mMinWidth = result);
}
/* virtual */ nscoord
FixedTableLayoutStrategy::GetPrefWidth(nsIRenderingContext* aRenderingContext,
PRBool aComputingSize)
{
// It's theoretically possible to do something much better here that
// depends only on the columns and the first row, but it wouldn't be
// compatible with other browsers.
nscoord result = nscoord_MAX;
DISPLAY_PREF_WIDTH(mTableFrame, result);
return result;
}
/* virtual */ void
FixedTableLayoutStrategy::MarkIntrinsicWidthsDirty()
{
mMinWidth = NS_INTRINSIC_WIDTH_UNKNOWN;
mLastCalcWidth = nscoord_MIN;
}
/* virtual */ void
FixedTableLayoutStrategy::ComputeColumnWidths(const nsHTMLReflowState& aReflowState)
{
nscoord tableWidth = aReflowState.ComputedWidth();
if (mLastCalcWidth == tableWidth)
return;
mLastCalcWidth = tableWidth;
nsTableCellMap *cellMap = mTableFrame->GetCellMap();
PRInt32 colCount = cellMap->GetColCount();
nscoord spacing = mTableFrame->GetCellSpacingX();
// XXX Should this code do any pixel rounding?
// border-spacing isn't part of the basis for percentages.
if (colCount > 0) {
// XXX Should only add columns that have cells originating in them!
nscoord subtract = spacing * (colCount + 1);
tableWidth -= subtract;
} else {
// No Columns - nothing to compute
return;
}
// XXX This ignores the 'min-width' and 'max-width' properties
// throughout. Then again, that's what the CSS spec says to do.
// XXX Consider widths on columns or column groups?
PRUint32 unassignedCount = 0;
nscoord unassignedSpace = tableWidth;
const nscoord unassignedMarker = nscoord_MIN;
// We use the PrefPercent on the columns to store the percentages
// used to compute column widths in case we need to reduce their
// basis.
float pctTotal = 0.0f;
for (PRInt32 col = 0; col < colCount; ++col) {
nsTableColFrame *colFrame = mTableFrame->GetColFrame(col);
if (!colFrame) {
NS_ERROR("column frames out of sync with cell map");
continue;
}
colFrame->ResetPrefPercent();
const nsStyleCoord *styleWidth =
&colFrame->GetStylePosition()->mWidth;
nscoord colWidth;
if (styleWidth->GetUnit() == eStyleUnit_Coord) {
colWidth = nsLayoutUtils::ComputeWidthValue(
aReflowState.rendContext,
colFrame, 0, 0, 0, *styleWidth);
} else if (styleWidth->GetUnit() == eStyleUnit_Percent) {
float pct = styleWidth->GetPercentValue();
colWidth = NSToCoordFloor(pct * float(tableWidth));
colFrame->AddPrefPercent(pct);
pctTotal += pct;
} else {
NS_ASSERTION(styleWidth->GetUnit() == eStyleUnit_Auto ||
styleWidth->GetUnit() == eStyleUnit_Enumerated,
"bad width");
// The 'table-layout: fixed' algorithm considers only cells
// in the first row.
PRBool originates;
PRInt32 colSpan;
nsTableCellFrame *cellFrame =
cellMap->GetCellInfoAt(0, col, &originates, &colSpan);
if (cellFrame) {
styleWidth = &cellFrame->GetStylePosition()->mWidth;
if (styleWidth->GetUnit() == eStyleUnit_Coord ||
(styleWidth->GetUnit() == eStyleUnit_Enumerated &&
(styleWidth->GetIntValue() == NS_STYLE_WIDTH_MAX_CONTENT ||
styleWidth->GetIntValue() == NS_STYLE_WIDTH_MIN_CONTENT))) {
// XXX This should use real percentage padding
// Note that the difference between MIN_WIDTH and
// PREF_WIDTH shouldn't matter for any of these
// values of styleWidth; use MIN_WIDTH for symmetry
// with GetMinWidth above, just in case there is a
// difference.
colWidth = nsLayoutUtils::IntrinsicForContainer(
aReflowState.rendContext,
cellFrame, nsLayoutUtils::MIN_WIDTH);
} else if (styleWidth->GetUnit() == eStyleUnit_Percent) {
// XXX This should use real percentage padding
nsIFrame::IntrinsicWidthOffsetData offsets =
cellFrame->IntrinsicWidthOffsets(aReflowState.rendContext);
float pct = styleWidth->GetPercentValue();
colWidth = NSToCoordFloor(pct * float(tableWidth)) +
offsets.hPadding + offsets.hBorder;
pct /= float(colSpan);
colFrame->AddPrefPercent(pct);
pctTotal += pct;
} else {
// 'auto', '-moz-available', and '-moz-fit-content'
colWidth = unassignedMarker;
}
if (colWidth != unassignedMarker) {
if (colSpan > 1) {
// If a column-spanning cell is in the first
// row, split up the space evenly. (XXX This
// isn't quite right if some of the columns it's
// in have specified widths. Should we care?)
colWidth = ((colWidth + spacing) / colSpan) - spacing;
if (colWidth < 0)
colWidth = 0;
}
}
} else {
colWidth = unassignedMarker;
}
}
colFrame->SetFinalWidth(colWidth);
if (colWidth == unassignedMarker) {
++unassignedCount;
} else {
unassignedSpace -= colWidth;
}
}
if (unassignedSpace < 0) {
if (pctTotal > 0) {
// If the columns took up too much space, reduce those that
// had percentage widths. The spec doesn't say to do this,
// but we've always done it in the past, and so does WinIE6.
nscoord pctUsed = NSToCoordFloor(pctTotal * float(tableWidth));
nscoord reduce = PR_MIN(pctUsed, -unassignedSpace);
float reduceRatio = float(reduce) / pctTotal;
for (PRInt32 col = 0; col < colCount; ++col) {
nsTableColFrame *colFrame = mTableFrame->GetColFrame(col);
if (!colFrame) {
NS_ERROR("column frames out of sync with cell map");
continue;
}
nscoord colWidth = colFrame->GetFinalWidth();
colWidth -= NSToCoordFloor(colFrame->GetPrefPercent() *
reduceRatio);
if (colWidth < 0)
colWidth = 0;
colFrame->SetFinalWidth(colWidth);
}
}
unassignedSpace = 0;
}
if (unassignedCount > 0) {
nscoord toAssign = unassignedSpace / unassignedCount;
for (PRInt32 col = 0; col < colCount; ++col) {
nsTableColFrame *colFrame = mTableFrame->GetColFrame(col);
if (!colFrame) {
NS_ERROR("column frames out of sync with cell map");
continue;
}
if (colFrame->GetFinalWidth() == unassignedMarker)
colFrame->SetFinalWidth(toAssign);
}
} else if (unassignedSpace > 0) {
// The spec says to distribute extra space evenly. (That's not
// what WinIE6 does, though. It treats percentages and
// nonpercentages differently.)
nscoord toAdd = unassignedSpace / colCount;
for (PRInt32 col = 0; col < colCount; ++col) {
nsTableColFrame *colFrame = mTableFrame->GetColFrame(col);
if (!colFrame) {
NS_ERROR("column frames out of sync with cell map");
continue;
}
colFrame->SetFinalWidth(colFrame->GetFinalWidth() + toAdd);
}
}
}