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gecko/layout/tables/BasicTableLayoutStrategy.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 ***** */
/*
* Web-compatible algorithms that determine column and table widths,
* used for CSS2's 'table-layout: auto'.
*/
#include "BasicTableLayoutStrategy.h"
#include "nsTableFrame.h"
#include "nsTableCellFrame.h"
#include "nsLayoutUtils.h"
#include "nsGkAtoms.h"
#include "SpanningCellSorter.h"
#undef DEBUG_TABLE_STRATEGY
BasicTableLayoutStrategy::BasicTableLayoutStrategy(nsTableFrame *aTableFrame)
: mTableFrame(aTableFrame)
{
MarkIntrinsicWidthsDirty();
}
/* virtual */
BasicTableLayoutStrategy::~BasicTableLayoutStrategy()
{
}
/* virtual */ nscoord
BasicTableLayoutStrategy::GetMinWidth(nsIRenderingContext* aRenderingContext)
{
DISPLAY_MIN_WIDTH(mTableFrame, mMinWidth);
if (mMinWidth == NS_INTRINSIC_WIDTH_UNKNOWN)
ComputeIntrinsicWidths(aRenderingContext);
return mMinWidth;
}
/* virtual */ nscoord
BasicTableLayoutStrategy::GetPrefWidth(nsIRenderingContext* aRenderingContext,
PRBool aComputingSize)
{
DISPLAY_PREF_WIDTH(mTableFrame, mPrefWidth);
NS_ASSERTION((mPrefWidth == NS_INTRINSIC_WIDTH_UNKNOWN) ==
(mPrefWidthPctExpand == NS_INTRINSIC_WIDTH_UNKNOWN),
"dirtyness out of sync");
if (mPrefWidth == NS_INTRINSIC_WIDTH_UNKNOWN)
ComputeIntrinsicWidths(aRenderingContext);
return aComputingSize ? mPrefWidthPctExpand : mPrefWidth;
}
struct CellWidthInfo {
CellWidthInfo(nscoord aMinCoord, nscoord aPrefCoord,
float aPrefPercent, PRBool aHasSpecifiedWidth)
: hasSpecifiedWidth(aHasSpecifiedWidth)
, minCoord(aMinCoord)
, prefCoord(aPrefCoord)
, prefPercent(aPrefPercent)
{
}
PRBool hasSpecifiedWidth;
nscoord minCoord;
nscoord prefCoord;
float prefPercent;
};
// Used for both column and cell calculations. The parts needed only
// for cells are skipped when aCellFrame is null.
static CellWidthInfo
GetWidthInfo(nsIRenderingContext *aRenderingContext,
nsIFrame *aFrame,
PRBool aIsCell,
const nsStylePosition *aStylePos)
{
nscoord minCoord, prefCoord;
if (aIsCell) {
minCoord = aFrame->GetMinWidth(aRenderingContext);
prefCoord = aFrame->GetPrefWidth(aRenderingContext);
} else {
minCoord = 0;
prefCoord = 0;
}
float prefPercent = 0.0f;
PRBool hasSpecifiedWidth = PR_FALSE;
// XXXldb Should we consider -moz-box-sizing?
nsStyleUnit unit = aStylePos->mWidth.GetUnit();
if (unit == eStyleUnit_Coord || unit == eStyleUnit_Chars) {
hasSpecifiedWidth = PR_TRUE;
nscoord w = nsLayoutUtils::ComputeWidthValue(aRenderingContext,
aFrame, 0, 0, 0, aStylePos->mWidth);
// Quirk: A cell with "nowrap" set and a coord value for the
// width which is bigger than the intrinsic minimum width uses
// that coord value as the minimum width.
// This is kept up-to-date with dynamic chnages to nowrap by code in
// nsTableCellFrame::AttributeChanged
if (aIsCell && w > minCoord &&
aFrame->PresContext()->CompatibilityMode() ==
eCompatibility_NavQuirks &&
aFrame->GetContent()->HasAttr(kNameSpaceID_None,
nsGkAtoms::nowrap)) {
minCoord = w;
}
prefCoord = PR_MAX(w, minCoord);
} else if (unit == eStyleUnit_Percent) {
prefPercent = aStylePos->mWidth.GetPercentValue();
} else if (unit == eStyleUnit_Enumerated && aIsCell) {
switch (aStylePos->mWidth.GetIntValue()) {
case NS_STYLE_WIDTH_INTRINSIC:
// 'width' only affects pref width, not min
// width, so don't change anything
break;
case NS_STYLE_WIDTH_MIN_INTRINSIC:
prefCoord = minCoord;
break;
case NS_STYLE_WIDTH_SHRINK_WRAP:
case NS_STYLE_WIDTH_FILL:
// act just like 'width: auto'
break;
default:
NS_NOTREACHED("unexpected enumerated value");
}
}
nsStyleCoord maxWidth(aStylePos->mMaxWidth);
if (maxWidth.GetUnit() == eStyleUnit_Enumerated) {
if (!aIsCell || maxWidth.GetIntValue() == NS_STYLE_WIDTH_FILL)
maxWidth.SetNoneValue();
else if (maxWidth.GetIntValue() == NS_STYLE_WIDTH_SHRINK_WRAP)
// for 'max-width', '-moz-shrink-wrap' is like
// '-moz-intrinsic'
maxWidth.SetIntValue(NS_STYLE_WIDTH_INTRINSIC,
eStyleUnit_Enumerated);
}
unit = maxWidth.GetUnit();
// XXX To really implement 'max-width' well, we'd need to store
// it separately on the columns.
if (unit == eStyleUnit_Coord || unit == eStyleUnit_Chars ||
unit == eStyleUnit_Enumerated) {
nscoord w =
nsLayoutUtils::ComputeWidthValue(aRenderingContext, aFrame,
0, 0, 0, maxWidth);
if (w < minCoord)
minCoord = w;
if (w < prefCoord)
prefCoord = w;
} else if (unit == eStyleUnit_Percent) {
float p = aStylePos->mMaxWidth.GetPercentValue();
if (p < prefPercent)
prefPercent = p;
}
nsStyleCoord minWidth(aStylePos->mMinWidth);
if (minWidth.GetUnit() == eStyleUnit_Enumerated) {
if (!aIsCell || minWidth.GetIntValue() == NS_STYLE_WIDTH_FILL)
minWidth.SetCoordValue(0);
else if (minWidth.GetIntValue() == NS_STYLE_WIDTH_SHRINK_WRAP)
// for 'min-width', '-moz-shrink-wrap' is like
// '-moz-min-intrinsic'
minWidth.SetIntValue(NS_STYLE_WIDTH_MIN_INTRINSIC,
eStyleUnit_Enumerated);
}
unit = minWidth.GetUnit();
if (unit == eStyleUnit_Coord || unit == eStyleUnit_Chars ||
unit == eStyleUnit_Enumerated) {
nscoord w =
nsLayoutUtils::ComputeWidthValue(aRenderingContext, aFrame,
0, 0, 0, minWidth);
if (w > minCoord)
minCoord = w;
if (w > prefCoord)
prefCoord = w;
} else if (unit == eStyleUnit_Percent) {
float p = aStylePos->mMinWidth.GetPercentValue();
if (p > prefPercent)
prefPercent = p;
}
// XXX Should col frame have border/padding considered?
if (aIsCell) {
nsIFrame::IntrinsicWidthOffsetData offsets =
aFrame->IntrinsicWidthOffsets(aRenderingContext);
// XXX Should we ignore percentage padding?
nscoord add = offsets.hPadding + offsets.hBorder;
minCoord += add;
prefCoord += add;
}
return CellWidthInfo(minCoord, prefCoord, prefPercent, hasSpecifiedWidth);
}
static inline CellWidthInfo
GetCellWidthInfo(nsIRenderingContext *aRenderingContext,
nsTableCellFrame *aCellFrame)
{
return GetWidthInfo(aRenderingContext, aCellFrame, PR_TRUE,
aCellFrame->GetStylePosition());
}
static inline CellWidthInfo
GetColWidthInfo(nsIRenderingContext *aRenderingContext,
nsIFrame *aFrame)
{
return GetWidthInfo(aRenderingContext, aFrame, PR_FALSE,
aFrame->GetStylePosition());
}
/**
* The algorithm in this function, in addition to meeting the
* requirements of Web-compatibility, is also invariant under reordering
* of the rows within a table (something that most, but not all, other
* browsers are).
*/
void
BasicTableLayoutStrategy::ComputeColumnIntrinsicWidths(nsIRenderingContext* aRenderingContext)
{
nsTableFrame *tableFrame = mTableFrame;
nsTableCellMap *cellMap = tableFrame->GetCellMap();
nscoord spacing = tableFrame->GetCellSpacingX();
SpanningCellSorter spanningCells(tableFrame->PresContext()->PresShell());
// Loop over the columns to consider the columns and cells *without*
// a colspan.
PRInt32 col, col_end;
for (col = 0, col_end = cellMap->GetColCount(); col < col_end; ++col) {
nsTableColFrame *colFrame = tableFrame->GetColFrame(col);
if (!colFrame) {
NS_ERROR("column frames out of sync with cell map");
continue;
}
colFrame->ResetIntrinsics();
colFrame->ResetSpanIntrinsics();
// Consider the widths on the column.
CellWidthInfo colInfo = GetColWidthInfo(aRenderingContext, colFrame);
colFrame->AddCoords(colInfo.minCoord, colInfo.prefCoord,
colInfo.hasSpecifiedWidth);
colFrame->AddPrefPercent(colInfo.prefPercent);
// Consider the widths on the column-group. Note that we follow
// what the HTML spec says here, and make the width apply to
// each column in the group, not the group as a whole.
// XXX Should we be doing this when we have widths on the column?
NS_ASSERTION(colFrame->GetParent()->GetType() ==
nsGkAtoms::tableColGroupFrame,
"expected a column-group");
colInfo = GetColWidthInfo(aRenderingContext, colFrame->GetParent());
colFrame->AddCoords(colInfo.minCoord, colInfo.prefCoord,
colInfo.hasSpecifiedWidth);
colFrame->AddPrefPercent(colInfo.prefPercent);
// Consider the contents of and the widths on the cells without
// colspans.
nsCellMapColumnIterator columnIter(cellMap, col);
PRInt32 row, colSpan;
nsTableCellFrame* cellFrame;
while ((cellFrame = columnIter.GetNextFrame(&row, &colSpan))) {
if (colSpan > 1) {
spanningCells.AddCell(colSpan, row, col);
continue;
}
CellWidthInfo info = GetCellWidthInfo(aRenderingContext, cellFrame);
colFrame->AddCoords(info.minCoord, info.prefCoord,
info.hasSpecifiedWidth);
colFrame->AddPrefPercent(info.prefPercent);
}
#ifdef DEBUG_dbaron_off
printf("table %p col %d nonspan: min=%d pref=%d spec=%d pct=%f\n",
mTableFrame, col, colFrame->GetMinCoord(),
colFrame->GetPrefCoord(), colFrame->GetHasSpecifiedCoord(),
colFrame->GetPrefPercent());
#endif
}
#ifdef DEBUG_TABLE_STRATEGY
printf("ComputeColumnIntrinsicWidths single\n");
mTableFrame->Dump(PR_FALSE, PR_TRUE, PR_FALSE);
#endif
// Consider the cells with a colspan that we saved in the loop above
// into the spanning cell sorter. We consider these cells by seeing
// if they require adding to the widths resulting only from cells
// with a smaller colspan, and therefore we must process them sorted
// in increasing order by colspan. For each colspan group, we
// accumulate new values to accumulate in the column frame's Span*
// members.
//
// Considering things only relative to the widths resulting from
// cells with smaller colspans (rather than incrementally including
// the results from spanning cells, or doing spanning and
// non-spanning cells in a single pass) means that layout remains
// row-order-invariant and (except for percentage widths that add to
// more than 100%) column-order invariant.
//
// Starting with smaller colspans makes it more likely that we
// satisfy all the constraints given and don't distribute space to
// columns where we don't need it.
SpanningCellSorter::Item *item;
PRInt32 colSpan;
while ((item = spanningCells.GetNext(&colSpan))) {
NS_ASSERTION(colSpan > 1,
"cell should not have been put in spanning cell sorter");
do {
PRInt32 row = item->row;
col = item->col;
CellData *cellData = cellMap->GetDataAt(row, col);
NS_ASSERTION(cellData && cellData->IsOrig(),
"bogus result from spanning cell sorter");
nsTableCellFrame *cellFrame = cellData->GetCellFrame();
NS_ASSERTION(cellFrame, "bogus result from spanning cell sorter");
CellWidthInfo info = GetCellWidthInfo(aRenderingContext, cellFrame);
// Before looping over the spanned columns to distribute
// this cell's width over the columns it spans, we first
// compute totals over the spanned columns so we know how to
// allocate the space.
// Accumulate information about the spanned columns, and
// subtract the already-used space from |info|.
nscoord totalSPref = 0, totalSMin = 0; // total existing widths
nscoord totalSNonPctPref = 0; // total pref width of columns
// without percentage widths
PRInt32 nonPctCount = 0; // # of columns without percentage widths
PRInt32 scol, scol_end;
for (scol = col, scol_end = col + colSpan;
scol < scol_end; ++scol) {
nsTableColFrame *scolFrame = tableFrame->GetColFrame(scol);
if (!scolFrame) {
NS_ERROR("column frames out of sync with cell map");
continue;
}
if (mTableFrame->GetNumCellsOriginatingInCol(scol) &&
scol != col) {
info.minCoord -= spacing;
info.prefCoord -= spacing;
}
nscoord curPref;
if (info.hasSpecifiedWidth &&
!scolFrame->GetHasSpecifiedCoord()) {
curPref = scolFrame->GetMinCoord();
} else {
curPref = scolFrame->GetPrefCoord();
}
totalSPref += curPref;
totalSMin += scolFrame->GetMinCoord();
float scolPct = scolFrame->GetPrefPercent();
if (scolPct == 0.0f) {
totalSNonPctPref += curPref;
++nonPctCount;
} else {
info.prefPercent -= scolPct;
}
info.minCoord -= scolFrame->GetMinCoord();
info.prefCoord -= curPref;
}
if (info.minCoord < 0)
info.minCoord = 0;
if (info.prefCoord < 0)
info.prefCoord = 0;
if (info.prefPercent < 0.0f)
info.prefPercent = 0.0f;
// The min-width of this cell that fits inside the
// pref-width of the spanned columns gets distributed
// according to different ratios.
nscoord minWithinPref =
PR_MIN(info.minCoord, totalSPref - totalSMin);
NS_ASSERTION(minWithinPref >= 0, "neither value can be negative");
nscoord minOutsidePref = info.minCoord - minWithinPref;
// Loop invariants (that we might get confused about as we
// subtract amounts for completed columns)
const PRBool spanHasNonPctPref = totalSNonPctPref > 0;
const PRBool spanHasPref = totalSPref > 0;
const PRBool spanHasNonPct = nonPctCount > 0;
// ... and actually do the distribution of the widths of
// this cell exceeding the totals already in the spanned
// columns.
for (scol = col, scol_end = col + colSpan;
scol < scol_end; ++scol) {
nsTableColFrame *scolFrame = tableFrame->GetColFrame(scol);
if (!scolFrame) {
NS_ERROR("column frames out of sync with cell map");
continue;
}
nscoord curPref;
if (info.hasSpecifiedWidth &&
!scolFrame->GetHasSpecifiedCoord()) {
curPref = scolFrame->GetMinCoord();
} else {
curPref = scolFrame->GetPrefCoord();
}
// the percentage width (only to columns that don't
// already have percentage widths, in proportion to
// the existing pref widths)
float allocatedPct = 0.0f;
if (scolFrame->GetPrefPercent() == 0.0f &&
info.prefPercent != 0.0f) {
NS_ASSERTION((!spanHasNonPctPref ||
totalSNonPctPref != 0) &&
nonPctCount != 0,
"should not be zero if we haven't allocated "
"all pref percent");
if (spanHasNonPctPref) {
// Group so we're multiplying by 1.0f when we need
// to use up info.prefPercent.
allocatedPct = info.prefPercent *
(float(curPref) /
float(totalSNonPctPref));
} else {
// distribute equally when all pref widths are 0
allocatedPct = info.prefPercent / float(nonPctCount);
}
scolFrame->AddSpanPrefPercent(allocatedPct);
}
// the part of the min width that fits within the
// existing pref width
float minRatio = 0.0f;
if (minWithinPref > 0) {
minRatio = float(curPref - scolFrame->GetMinCoord()) /
float(totalSPref - totalSMin);
}
// the rest of the min width, and the pref width (in
// proportion to the existing pref widths)
float coordRatio; // for both min and pref
if (spanHasPref) {
if (curPref == 0) {
// We might have already subtracted all of
// totalSPref.
coordRatio = 0.0f;
} else {
coordRatio = float(curPref) / float(totalSPref);
}
} else {
// distribute equally when all pref widths are 0
coordRatio = 1.0f / float(scol_end - scol);
}
// combine the two min-width distributions, and record
// min and pref
nscoord allocatedMinWithinPref =
NSToCoordRound(float(minWithinPref) * minRatio);
nscoord allocatedMinOutsidePref =
NSToCoordRound(float(minOutsidePref) * coordRatio);
nscoord allocatedPref =
NSToCoordRound(float(info.prefCoord) * coordRatio);
nscoord spanMin = scolFrame->GetMinCoord() +
allocatedMinWithinPref + allocatedMinOutsidePref;
nscoord spanPref = curPref + allocatedPref;
scolFrame->AddSpanCoords(spanMin, spanPref,
info.hasSpecifiedWidth);
// To avoid accumulating rounding error from division,
// subtract everything to do with the column we've
// passed from the totals.
minWithinPref -= allocatedMinWithinPref;
minOutsidePref -= allocatedMinOutsidePref;
info.prefCoord -= allocatedPref;
info.prefPercent -= allocatedPct;
totalSPref -= curPref;
totalSMin -= scolFrame->GetMinCoord();
if (scolFrame->GetPrefPercent() == 0.0f) {
totalSNonPctPref -= curPref;
--nonPctCount;
}
}
// Note that we only distribute the percentage if
// spanHasNonPct.
NS_ASSERTION(totalSPref == 0 && totalSMin == 0 &&
totalSNonPctPref == 0 && nonPctCount == 0 &&
minOutsidePref == 0 && minWithinPref == 0 &&
info.prefCoord == 0 &&
(info.prefPercent == 0.0f || !spanHasNonPct),
"didn't subtract all that we added");
} while ((item = item->next));
// Combine the results of the span analysis into the main results,
// for each increment of colspan.
for (col = 0, col_end = cellMap->GetColCount(); col < col_end; ++col) {
nsTableColFrame *colFrame = tableFrame->GetColFrame(col);
if (!colFrame) {
NS_ERROR("column frames out of sync with cell map");
continue;
}
colFrame->AccumulateSpanIntrinsics();
colFrame->ResetSpanIntrinsics();
#ifdef DEBUG_dbaron_off
printf("table %p col %d span %d: min=%d pref=%d spec=%d pct=%f\n",
mTableFrame, col, colSpan, colFrame->GetMinCoord(),
colFrame->GetPrefCoord(), colFrame->GetHasSpecifiedCoord(),
colFrame->GetPrefPercent());
#endif
}
}
// Prevent percentages from adding to more than 100% by (to be
// compatible with other browsers) treating any percentages that would
// increase the total percentage to more than 100% as the number that
// would increase it to only 100% (which is 0% if we've already hit
// 100%). This means layout depends on the order of columns.
float pct_used = 0.0f;
for (col = 0, col_end = cellMap->GetColCount(); col < col_end; ++col) {
nsTableColFrame *colFrame = tableFrame->GetColFrame(col);
if (!colFrame) {
NS_ERROR("column frames out of sync with cell map");
continue;
}
colFrame->AdjustPrefPercent(&pct_used);
}
#ifdef DEBUG_TABLE_STRATEGY
printf("ComputeColumnIntrinsicWidths spanning\n");
mTableFrame->Dump(PR_FALSE, PR_TRUE, PR_FALSE);
#endif
}
void
BasicTableLayoutStrategy::ComputeIntrinsicWidths(nsIRenderingContext* aRenderingContext)
{
ComputeColumnIntrinsicWidths(aRenderingContext);
nsTableCellMap *cellMap = mTableFrame->GetCellMap();
nscoord min = 0, pref = 0, max_small_pct_pref = 0, nonpct_pref_total = 0;
float pct_total = 0.0f; // always from 0.0f - 1.0f
PRInt32 colCount = cellMap->GetColCount();
nscoord spacing = mTableFrame->GetCellSpacingX();
nscoord add = spacing; // add (colcount + 1) * spacing for columns
// where a cell originates
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 (mTableFrame->GetNumCellsOriginatingInCol(col)) {
add += spacing;
}
min += colFrame->GetMinCoord();
pref += colFrame->GetPrefCoord();
// Percentages are of the table, so we have to reverse them for
// intrinsic widths.
float p = colFrame->GetPrefPercent();
if (p > 0.0f) {
nscoord new_small_pct_expand =
nscoord(float(colFrame->GetPrefCoord()) / p);
if (new_small_pct_expand > max_small_pct_pref) {
max_small_pct_pref = new_small_pct_expand;
}
pct_total += p;
} else {
nonpct_pref_total += colFrame->GetPrefCoord();
}
}
nscoord pref_pct_expand = pref;
// Account for small percentages expanding the preferred width of
// *other* columns.
if (max_small_pct_pref > pref_pct_expand) {
pref_pct_expand = max_small_pct_pref;
}
// Account for large percentages expanding the preferred width of
// themselves. There's no need to iterate over the columns multiple
// times, since when there is such a need, the small percentage
// effect is bigger anyway. (I think!)
NS_ASSERTION(0.0f <= pct_total && pct_total <= 1.0f,
"column percentage widths not adjusted down to 100%");
if (pct_total == 1.0f) {
if (nonpct_pref_total > 0) {
pref_pct_expand = nscoord_MAX;
// XXX Or should I use some smaller value? (Test this using
// nested tables!)
}
} else {
nscoord large_pct_pref = nscoord(float(nonpct_pref_total) /
(1.0f - pct_total));
if (large_pct_pref > pref_pct_expand)
pref_pct_expand = large_pct_pref;
}
// border-spacing isn't part of the basis for percentages
if (colCount > 0) {
min += add;
pref += add;
pref_pct_expand += add;
}
mMinWidth = min;
mPrefWidth = pref;
mPrefWidthPctExpand = pref_pct_expand;
}
/* virtual */ void
BasicTableLayoutStrategy::MarkIntrinsicWidthsDirty()
{
mMinWidth = NS_INTRINSIC_WIDTH_UNKNOWN;
mPrefWidth = NS_INTRINSIC_WIDTH_UNKNOWN;
mPrefWidthPctExpand = NS_INTRINSIC_WIDTH_UNKNOWN;
mLastCalcWidth = nscoord_MIN;
}
/* virtual */ void
BasicTableLayoutStrategy::ComputeColumnWidths(const nsHTMLReflowState& aReflowState)
{
nscoord width = aReflowState.ComputedWidth();
if (mLastCalcWidth == width)
return;
mLastCalcWidth = width;
NS_ASSERTION((mMinWidth == NS_INTRINSIC_WIDTH_UNKNOWN) ==
(mPrefWidth == NS_INTRINSIC_WIDTH_UNKNOWN),
"dirtyness out of sync");
NS_ASSERTION((mMinWidth == NS_INTRINSIC_WIDTH_UNKNOWN) ==
(mPrefWidthPctExpand == NS_INTRINSIC_WIDTH_UNKNOWN),
"dirtyness out of sync");
// XXX Is this needed?
if (mMinWidth == NS_INTRINSIC_WIDTH_UNKNOWN)
ComputeIntrinsicWidths(aReflowState.rendContext);
nsTableCellMap *cellMap = mTableFrame->GetCellMap();
PRInt32 colCount = cellMap->GetColCount();
if (colCount <= 0)
return; // nothing to do
nscoord spacing = mTableFrame->GetCellSpacingX();
nscoord min = mMinWidth;
// border-spacing isn't part of the basis for percentages.
nscoord subtract = spacing;
for (PRInt32 col = 0; col < colCount; ++col) {
if (mTableFrame->GetNumCellsOriginatingInCol(col)) {
subtract += spacing;
}
}
width -= subtract;
min -= subtract;
// XXX is |width| the right basis for percentage widths?
/*
* The goal of this function is to allocate |width| to the columns
* by making an appropriate SetFinalWidth call to each column.
*
* The idea is to either assign one of the following sets of widths
* or a weighted average of two adjacent sets of widths. It is not
* possible to assign values smaller than the smallest set of
* widths. However, see below for handling the case of assigning
* values larger than the largest set of widths. From smallest to
* largest, these are:
*
* 1. [guess_min] Assign all columns their min width.
*
* 2. [guess_min_pct] Assign all columns with percentage widths
* their percentage width, and all other columns their min width.
*
* 3. [guess_min_spec] Assign all columns with percentage widths
* their percentage width, all columns with specified coordinate
* widths their pref width (since it doesn't matter whether it's the
* largest contributor to the pref width that was the specified
* contributor), and all other columns their min width.
*
* 4. [guess_pref] Assign all columns with percentage widths their
* specified width, and all other columns their pref width.
*
* If |width| is *larger* than what we would assign in (4), then we
* expand the columns:
*
* a. if any columns without a specified coordinate width or
* percent width have nonzero pref width, in proportion to pref
* width [total_flex_pref]
*
* b. otherwise, if any columns without percent width have nonzero
* pref width, in proportion to pref width [total_fixed_pref]
*
* c. otherwise, if any columns have nonzero percentage widths, in
* proportion to the percentage widths [total_pct]
*
* d. otherwise, equally.
*/
// Loop #1 over the columns, to figure out the four values above so
// we know which case we're dealing with.
nscoord guess_min = 0,
guess_min_pct = 0,
guess_min_spec = 0,
guess_pref = 0,
total_flex_pref = 0,
total_fixed_pref = 0;
float total_pct = 0.0f; // 0.0f to 1.0f
PRInt32 col;
for (col = 0; col < colCount; ++col) {
nsTableColFrame *colFrame = mTableFrame->GetColFrame(col);
if (!colFrame) {
NS_ERROR("column frames out of sync with cell map");
continue;
}
nscoord min_width = colFrame->GetMinCoord();
guess_min += min_width;
if (colFrame->GetPrefPercent() != 0.0f) {
float pct = colFrame->GetPrefPercent();
total_pct += pct;
nscoord val = nscoord(float(width) * pct);
if (val < min_width)
val = min_width;
guess_min_pct += val;
guess_pref += val;
} else {
nscoord pref_width = colFrame->GetPrefCoord();
guess_pref += pref_width;
guess_min_pct += min_width;
if (colFrame->GetHasSpecifiedCoord()) {
// we'll add on the rest of guess_min_spec outside the
// loop
guess_min_spec += pref_width - min_width;
total_fixed_pref += pref_width;
} else {
total_flex_pref += pref_width;
}
}
}
guess_min_spec += guess_min_pct;
// Determine what we're flexing:
enum Loop2Type {
FLEX_PCT_SMALL, // between (1) and (2) above
FLEX_FIXED_SMALL, // between (2) and (3) above
FLEX_FLEX_SMALL, // between (3) and (4) above
FLEX_FLEX_LARGE, // above (4) above, case (a)
FLEX_FIXED_LARGE, // above (4) above, case (b)
FLEX_PCT_LARGE, // above (4) above, case (c)
FLEX_ALL_LARGE // above (4) above, case (d)
};
Loop2Type l2t;
// These are constants (over columns) for each case's math. We use
// a pair of nscoords rather than a float so that we can subtract
// each column's allocation so we avoid accumulating rounding error.
nscoord space; // the amount of extra width to allocate
union {
nscoord c;
float f;
} basis; // the sum of the statistic over columns to divide it
if (width < guess_pref) {
NS_ASSERTION(width >= guess_min, "bad width");
if (width < guess_min_pct) {
l2t = FLEX_PCT_SMALL;
space = width - guess_min;
basis.c = guess_min_pct - guess_min;
} else if (width < guess_min_spec) {
l2t = FLEX_FIXED_SMALL;
space = width - guess_min_pct;
basis.c = guess_min_spec - guess_min_pct;
} else {
l2t = FLEX_FLEX_SMALL;
space = width - guess_min_spec;
basis.c = guess_pref - guess_min_spec;
}
} else {
space = width - guess_pref;
if (total_flex_pref > 0) {
l2t = FLEX_FLEX_LARGE;
basis.c = total_flex_pref;
} else if (total_fixed_pref > 0) {
l2t = FLEX_FIXED_LARGE;
basis.c = total_fixed_pref;
} else if (total_pct > 0.0f) {
l2t = FLEX_PCT_LARGE;
basis.f = total_pct;
} else {
l2t = FLEX_ALL_LARGE;
basis.c = colCount;
}
}
#ifdef DEBUG_dbaron_off
printf("ComputeColumnWidths: %d columns in width %d,\n"
" guesses=[%d,%d,%d,%d], totals=[%d,%d,%f],\n"
" l2t=%d, space=%d, basis.c=%d\n",
colCount, width,
guess_min, guess_min_pct, guess_min_spec, guess_pref,
total_flex_pref, total_fixed_pref, total_pct,
l2t, space, basis.c);
#endif
for (col = 0; col < colCount; ++col) {
nsTableColFrame *colFrame = mTableFrame->GetColFrame(col);
if (!colFrame) {
NS_ERROR("column frames out of sync with cell map");
continue;
}
nscoord col_width;
float pct = colFrame->GetPrefPercent();
if (pct != 0.0f) {
col_width = nscoord(float(width) * pct);
nscoord col_min = colFrame->GetMinCoord();
if (col_width < col_min)
col_width = col_min;
} else {
col_width = colFrame->GetPrefCoord();
}
nscoord col_width_before_adjust = col_width;
switch (l2t) {
case FLEX_PCT_SMALL:
col_width = col_width_before_adjust = colFrame->GetMinCoord();
if (pct != 0.0f) {
nscoord pct_minus_min =
nscoord(float(width) * pct) - col_width;
if (pct_minus_min > 0) {
float c = float(space) / float(basis.c);
basis.c -= pct_minus_min;
col_width += NSToCoordRound(float(pct_minus_min) * c);
}
}
break;
case FLEX_FIXED_SMALL:
if (pct == 0.0f) {
NS_ASSERTION(col_width == colFrame->GetPrefCoord(),
"wrong width assigned");
if (colFrame->GetHasSpecifiedCoord()) {
nscoord col_min = colFrame->GetMinCoord();
nscoord pref_minus_min = col_width - col_min;
col_width = col_width_before_adjust = col_min;
if (pref_minus_min != 0) {
float c = float(space) / float(basis.c);
basis.c -= pref_minus_min;
col_width += NSToCoordRound(
float(pref_minus_min) * c);
}
} else
col_width = col_width_before_adjust =
colFrame->GetMinCoord();
}
break;
case FLEX_FLEX_SMALL:
if (pct == 0.0f &&
!colFrame->GetHasSpecifiedCoord()) {
NS_ASSERTION(col_width == colFrame->GetPrefCoord(),
"wrong width assigned");
nscoord col_min = colFrame->GetMinCoord();
nscoord pref_minus_min = col_width - col_min;
col_width = col_width_before_adjust = col_min;
if (pref_minus_min != 0) {
float c = float(space) / float(basis.c);
basis.c -= pref_minus_min;
col_width += NSToCoordRound(
float(pref_minus_min) * c);
}
}
break;
case FLEX_FLEX_LARGE:
if (pct == 0.0f &&
!colFrame->GetHasSpecifiedCoord()) {
NS_ASSERTION(col_width == colFrame->GetPrefCoord(),
"wrong width assigned");
if (col_width != 0) {
float c = float(space) / float(basis.c);
basis.c -= col_width;
col_width += NSToCoordRound(float(col_width) * c);
}
}
break;
case FLEX_FIXED_LARGE:
if (pct == 0.0f) {
NS_ASSERTION(col_width == colFrame->GetPrefCoord(),
"wrong width assigned");
NS_ASSERTION(colFrame->GetHasSpecifiedCoord() ||
colFrame->GetPrefCoord() == 0,
"wrong case");
if (col_width != 0) {
float c = float(space) / float(basis.c);
basis.c -= col_width;
col_width += NSToCoordRound(float(col_width) * c);
}
}
break;
case FLEX_PCT_LARGE:
NS_ASSERTION(pct != 0.0f || colFrame->GetPrefCoord() == 0,
"wrong case");
if (pct != 0.0f) {
float c = float(space) / basis.f;
col_width += NSToCoordRound(pct * c);
basis.f -= pct;
}
break;
case FLEX_ALL_LARGE:
{
float c = float(space) / float(basis.c);
col_width += NSToCoordRound(c);
--basis.c;
}
break;
}
space -= col_width - col_width_before_adjust;
NS_ASSERTION(col_width >= colFrame->GetMinCoord(),
"assigned width smaller than min");
nscoord old_final = colFrame->GetFinalWidth();
colFrame->SetFinalWidth(col_width);
if (old_final != col_width)
mTableFrame->DidResizeColumns();
}
NS_ASSERTION(space == 0 &&
((l2t == FLEX_PCT_LARGE)
? (-0.001f < basis.f && basis.f < 0.001f)
: (basis.c == 0)),
"didn't subtract all that we added");
#ifdef DEBUG_TABLE_STRATEGY
printf("ComputeColumnWidths final\n");
mTableFrame->Dump(PR_FALSE, PR_TRUE, PR_FALSE);
#endif
}
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