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gecko-dev/layout/tables/BasicTableLayoutStrategy.cpp
Ehsan Akhgari 92064e6d3f Bug 690892 - Replace PR_TRUE/PR_FALSE with true/false on mozilla-central; rs=dbaron 
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2011-10-17 10:59:28 -04:00

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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"
namespace css = mozilla::css;
#undef DEBUG_TABLE_STRATEGY
BasicTableLayoutStrategy::BasicTableLayoutStrategy(nsTableFrame *aTableFrame)
: nsITableLayoutStrategy(nsITableLayoutStrategy::Auto)
, mTableFrame(aTableFrame)
{
MarkIntrinsicWidthsDirty();
}
/* virtual */
BasicTableLayoutStrategy::~BasicTableLayoutStrategy()
{
}
/* virtual */ nscoord
BasicTableLayoutStrategy::GetMinWidth(nsRenderingContext* aRenderingContext)
{
DISPLAY_MIN_WIDTH(mTableFrame, mMinWidth);
if (mMinWidth == NS_INTRINSIC_WIDTH_UNKNOWN)
ComputeIntrinsicWidths(aRenderingContext);
return mMinWidth;
}
/* virtual */ nscoord
BasicTableLayoutStrategy::GetPrefWidth(nsRenderingContext* aRenderingContext,
bool 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, bool aHasSpecifiedWidth)
: hasSpecifiedWidth(aHasSpecifiedWidth)
, minCoord(aMinCoord)
, prefCoord(aPrefCoord)
, prefPercent(aPrefPercent)
{
}
bool hasSpecifiedWidth;
nscoord minCoord;
nscoord prefCoord;
float prefPercent;
};
// Used for both column and cell calculations. The parts needed only
// for cells are skipped when aIsCell is false.
static CellWidthInfo
GetWidthInfo(nsRenderingContext *aRenderingContext,
nsIFrame *aFrame, bool aIsCell)
{
nscoord minCoord, prefCoord;
if (aIsCell) {
minCoord = aFrame->GetMinWidth(aRenderingContext);
prefCoord = aFrame->GetPrefWidth(aRenderingContext);
} else {
minCoord = 0;
prefCoord = 0;
}
float prefPercent = 0.0f;
bool hasSpecifiedWidth = false;
// XXXldb Should we consider -moz-box-sizing?
const nsStylePosition *stylePos = aFrame->GetStylePosition();
const nsStyleCoord &width = stylePos->mWidth;
nsStyleUnit unit = width.GetUnit();
// NOTE: We're ignoring calc() units here, for lack of a sensible
// idea for what to do with them. This means calc() is basically
// handled like 'auto' for table cells and columns.
if (unit == eStyleUnit_Coord) {
hasSpecifiedWidth = true;
nscoord w = nsLayoutUtils::ComputeWidthValue(aRenderingContext,
aFrame, 0, 0, 0, width);
// 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 changes 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 = NS_MAX(w, minCoord);
} else if (unit == eStyleUnit_Percent) {
prefPercent = width.GetPercentValue();
} else if (unit == eStyleUnit_Enumerated && aIsCell) {
switch (width.GetIntValue()) {
case NS_STYLE_WIDTH_MAX_CONTENT:
// 'width' only affects pref width, not min
// width, so don't change anything
break;
case NS_STYLE_WIDTH_MIN_CONTENT:
prefCoord = minCoord;
break;
case NS_STYLE_WIDTH_FIT_CONTENT:
case NS_STYLE_WIDTH_AVAILABLE:
// act just like 'width: auto'
break;
default:
NS_NOTREACHED("unexpected enumerated value");
}
}
nsStyleCoord maxWidth(stylePos->mMaxWidth);
if (maxWidth.GetUnit() == eStyleUnit_Enumerated) {
if (!aIsCell || maxWidth.GetIntValue() == NS_STYLE_WIDTH_AVAILABLE)
maxWidth.SetNoneValue();
else if (maxWidth.GetIntValue() == NS_STYLE_WIDTH_FIT_CONTENT)
// for 'max-width', '-moz-fit-content' is like
// '-moz-max-content'
maxWidth.SetIntValue(NS_STYLE_WIDTH_MAX_CONTENT,
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_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 = stylePos->mMaxWidth.GetPercentValue();
if (p < prefPercent)
prefPercent = p;
}
// treat calc() on max-width just like 'none'.
nsStyleCoord minWidth(stylePos->mMinWidth);
if (minWidth.GetUnit() == eStyleUnit_Enumerated) {
if (!aIsCell || minWidth.GetIntValue() == NS_STYLE_WIDTH_AVAILABLE)
minWidth.SetCoordValue(0);
else if (minWidth.GetIntValue() == NS_STYLE_WIDTH_FIT_CONTENT)
// for 'min-width', '-moz-fit-content' is like
// '-moz-min-content'
minWidth.SetIntValue(NS_STYLE_WIDTH_MIN_CONTENT,
eStyleUnit_Enumerated);
}
unit = minWidth.GetUnit();
if (unit == eStyleUnit_Coord || 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 = stylePos->mMinWidth.GetPercentValue();
if (p > prefPercent)
prefPercent = p;
}
// treat calc() on min-width just like '0'.
// 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 = NSCoordSaturatingAdd(prefCoord, add);
}
return CellWidthInfo(minCoord, prefCoord, prefPercent, hasSpecifiedWidth);
}
static inline CellWidthInfo
GetCellWidthInfo(nsRenderingContext *aRenderingContext,
nsTableCellFrame *aCellFrame)
{
return GetWidthInfo(aRenderingContext, aCellFrame, true);
}
static inline CellWidthInfo
GetColWidthInfo(nsRenderingContext *aRenderingContext,
nsIFrame *aFrame)
{
return GetWidthInfo(aRenderingContext, aFrame, false);
}
/**
* 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(nsRenderingContext* aRenderingContext)
{
nsTableFrame *tableFrame = mTableFrame;
nsTableCellMap *cellMap = tableFrame->GetCellMap();
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.
// If column has width, column-group doesn't override width.
if (colInfo.minCoord == 0 && colInfo.prefCoord == 0 &&
colInfo.prefPercent == 0.0f) {
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(false, true, 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);
if (info.prefPercent > 0.0f) {
DistributePctWidthToColumns(info.prefPercent,
col, colSpan);
}
DistributeWidthToColumns(info.minCoord, col, colSpan,
BTLS_MIN_WIDTH, info.hasSpecifiedWidth);
DistributeWidthToColumns(info.prefCoord, col, colSpan,
BTLS_PREF_WIDTH, info.hasSpecifiedWidth);
} 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(false, true, false);
#endif
}
void
BasicTableLayoutStrategy::ComputeIntrinsicWidths(nsRenderingContext* 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->ColumnHasCellSpacingBefore(col)) {
add += spacing;
}
min += colFrame->GetMinCoord();
pref = NSCoordSaturatingAdd(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 colPref = colFrame->GetPrefCoord();
nscoord new_small_pct_expand =
(colPref == nscoord_MAX ?
nscoord_MAX : nscoord(float(colPref) / 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 = NSCoordSaturatingAdd(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 =
(nonpct_pref_total == nscoord_MAX ?
nscoord_MAX :
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 = NSCoordSaturatingAdd(pref, add);
pref_pct_expand = NSCoordSaturatingAdd(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
DistributeWidthToColumns(width, 0, colCount, BTLS_FINAL_WIDTH, false);
#ifdef DEBUG_TABLE_STRATEGY
printf("ComputeColumnWidths final\n");
mTableFrame->Dump(false, true, false);
#endif
}
void
BasicTableLayoutStrategy::DistributePctWidthToColumns(float aSpanPrefPct,
PRInt32 aFirstCol,
PRInt32 aColCount)
{
// First loop to determine:
PRInt32 nonPctColCount = 0; // number of spanned columns without % width
nscoord nonPctTotalPrefWidth = 0; // total pref width of those columns
// and to reduce aSpanPrefPct by columns that already have % width
PRInt32 scol, scol_end;
for (scol = aFirstCol, scol_end = aFirstCol + aColCount;
scol < scol_end; ++scol) {
nsTableColFrame *scolFrame = mTableFrame->GetColFrame(scol);
if (!scolFrame) {
NS_ERROR("column frames out of sync with cell map");
continue;
}
float scolPct = scolFrame->GetPrefPercent();
if (scolPct == 0.0f) {
nonPctTotalPrefWidth += scolFrame->GetPrefCoord();
++nonPctColCount;
} else {
aSpanPrefPct -= scolPct;
}
}
if (aSpanPrefPct <= 0.0f || nonPctColCount == 0) {
// There's no %-width on the colspan left over to distribute,
// or there are no columns to which we could distribute %-width
return;
}
// Second loop, to distribute what remains of aSpanPrefPct
// between the non-percent-width spanned columns
const bool spanHasNonPctPref = nonPctTotalPrefWidth > 0; // Loop invariant
for (scol = aFirstCol, scol_end = aFirstCol + aColCount;
scol < scol_end; ++scol) {
nsTableColFrame *scolFrame = mTableFrame->GetColFrame(scol);
if (!scolFrame) {
NS_ERROR("column frames out of sync with cell map");
continue;
}
if (scolFrame->GetPrefPercent() == 0.0f) {
NS_ASSERTION((!spanHasNonPctPref ||
nonPctTotalPrefWidth != 0) &&
nonPctColCount != 0,
"should not be zero if we haven't allocated "
"all pref percent");
float allocatedPct; // % width to be given to this column
if (spanHasNonPctPref) {
// Group so we're multiplying by 1.0f when we need
// to use up aSpanPrefPct.
allocatedPct = aSpanPrefPct *
(float(scolFrame->GetPrefCoord()) /
float(nonPctTotalPrefWidth));
} else {
// distribute equally when all pref widths are 0
allocatedPct = aSpanPrefPct / float(nonPctColCount);
}
// Allocate the percent
scolFrame->AddSpanPrefPercent(allocatedPct);
// To avoid accumulating rounding error from division,
// subtract this column's values from the totals.
aSpanPrefPct -= allocatedPct;
nonPctTotalPrefWidth -= scolFrame->GetPrefCoord();
--nonPctColCount;
if (!aSpanPrefPct) {
// No more span-percent-width to distribute --> we're done.
NS_ASSERTION(spanHasNonPctPref ?
nonPctTotalPrefWidth == 0 :
nonPctColCount == 0,
"No more pct width to distribute, but there are "
"still cols that need some.");
return;
}
}
}
}
void
BasicTableLayoutStrategy::DistributeWidthToColumns(nscoord aWidth,
PRInt32 aFirstCol,
PRInt32 aColCount,
BtlsWidthType aWidthType,
bool aSpanHasSpecifiedWidth)
{
NS_ASSERTION(aWidthType != BTLS_FINAL_WIDTH ||
(aFirstCol == 0 &&
aColCount == mTableFrame->GetCellMap()->GetColCount()),
"Computing final column widths, but didn't get full column range");
// border-spacing isn't part of the basis for percentages.
nscoord spacing = mTableFrame->GetCellSpacingX();
nscoord subtract = 0;
// aWidth initially includes border-spacing for the boundaries in between
// each of the columns. We start at aFirstCol + 1 because the first
// in-between boundary would be at the left edge of column aFirstCol + 1
for (PRInt32 col = aFirstCol + 1; col < aFirstCol + aColCount; ++col) {
if (mTableFrame->ColumnHasCellSpacingBefore(col)) {
subtract += spacing;
}
}
if (aWidthType == BTLS_FINAL_WIDTH) {
// If we're computing final col-width, then aWidth initially includes
// border spacing on the table's far left + far right edge, too. Need
// to subtract those out, too.
subtract += spacing * 2;
}
aWidth = NSCoordSaturatingSubtract(aWidth, subtract, nscoord_MAX);
/*
* The goal of this function is to distribute |aWidth| between the
* columns by making an appropriate AddSpanCoords or SetFinalWidth
* call for each column. (We call AddSpanCoords if we're
* distributing a column-spanning cell's minimum or preferred width
* to its spanned columns. We call SetFinalWidth if we're
* distributing a table's final width to its columns.)
*
* 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 |aWidth| 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. (NOTE: this case is for BTLS_FINAL_WIDTH only) otherwise, if
* any columns without a specified coordinate width or percent
* width, but with cells originating in them have zero pref width,
* equally between these [numNonSpecZeroWidthCols]
*
* c. otherwise, if any columns without percent width have nonzero
* pref width, in proportion to pref width [total_fixed_pref]
*
* d. otherwise, if any columns have nonzero percentage widths, in
* proportion to the percentage widths [total_pct]
*
* e. 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 numInfiniteWidthCols = 0;
PRInt32 numNonSpecZeroWidthCols = 0;
PRInt32 col;
nsTableCellMap *cellMap = mTableFrame->GetCellMap();
for (col = aFirstCol; col < aFirstCol + aColCount; ++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(aWidth) * pct);
if (val < min_width)
val = min_width;
guess_min_pct += val;
guess_pref = NSCoordSaturatingAdd(guess_pref, val);
} else {
nscoord pref_width = colFrame->GetPrefCoord();
if (pref_width == nscoord_MAX) {
++numInfiniteWidthCols;
}
guess_pref = NSCoordSaturatingAdd(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
nscoord delta = NSCoordSaturatingSubtract(pref_width,
min_width, 0);
guess_min_spec = NSCoordSaturatingAdd(guess_min_spec, delta);
total_fixed_pref = NSCoordSaturatingAdd(total_fixed_pref,
pref_width);
} else if (pref_width == 0) {
if (aWidthType == BTLS_FINAL_WIDTH &&
cellMap->GetNumCellsOriginatingInCol(col) > 0) {
++numNonSpecZeroWidthCols;
}
} else {
total_flex_pref = NSCoordSaturatingAdd(total_flex_pref,
pref_width);
}
}
}
guess_min_spec = NSCoordSaturatingAdd(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, // greater than (4) above, case (a)
FLEX_FLEX_LARGE_ZERO, // greater than (4) above, case (b)
FLEX_FIXED_LARGE, // greater than (4) above, case (c)
FLEX_PCT_LARGE, // greater than (4) above, case (d)
FLEX_ALL_LARGE // greater than (4) above, case (e)
};
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 (aWidth < guess_pref) {
if (aWidthType != BTLS_FINAL_WIDTH && aWidth <= guess_min) {
// Return early -- we don't have any extra space to distribute.
return;
}
NS_ASSERTION(!(aWidthType == BTLS_FINAL_WIDTH && aWidth < guess_min),
"Table width is less than the "
"sum of its columns' min widths");
if (aWidth < guess_min_pct) {
l2t = FLEX_PCT_SMALL;
space = aWidth - guess_min;
basis.c = guess_min_pct - guess_min;
} else if (aWidth < guess_min_spec) {
l2t = FLEX_FIXED_SMALL;
space = aWidth - guess_min_pct;
basis.c = NSCoordSaturatingSubtract(guess_min_spec, guess_min_pct,
nscoord_MAX);
} else {
l2t = FLEX_FLEX_SMALL;
space = aWidth - guess_min_spec;
basis.c = NSCoordSaturatingSubtract(guess_pref, guess_min_spec,
nscoord_MAX);
}
} else {
space = NSCoordSaturatingSubtract(aWidth, guess_pref, nscoord_MAX);
if (total_flex_pref > 0) {
l2t = FLEX_FLEX_LARGE;
basis.c = total_flex_pref;
} else if (numNonSpecZeroWidthCols > 0) {
NS_ASSERTION(aWidthType == BTLS_FINAL_WIDTH,
"numNonSpecZeroWidthCols should only "
"be set when we're setting final width.");
l2t = FLEX_FLEX_LARGE_ZERO;
basis.c = numNonSpecZeroWidthCols;
} 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 = aColCount;
}
}
#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",
aColCount, aWidth,
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 = aFirstCol; col < aFirstCol + aColCount; ++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(aWidth) * 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(aWidth) * 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 =
NSCoordSaturatingSubtract(col_width, col_min, 0);
col_width = col_width_before_adjust = col_min;
if (pref_minus_min != 0) {
float c = float(space) / float(basis.c);
// If we have infinite-width cols, then the standard
// adjustment to col_width using 'c' won't work,
// because basis.c and pref_minus_min are both
// nscoord_MAX and will cancel each other out in the
// col_width adjustment (making us assign all the
// space to the first inf-width col). To correct for
// this, we'll also divide by numInfiniteWidthCols to
// spread the space equally among the inf-width cols.
if (numInfiniteWidthCols) {
if (colFrame->GetPrefCoord() == nscoord_MAX) {
c = c / float(numInfiniteWidthCols);
--numInfiniteWidthCols;
} else {
c = 0.0f;
}
}
basis.c = NSCoordSaturatingSubtract(basis.c,
pref_minus_min,
nscoord_MAX);
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) {
if (space == nscoord_MAX) {
basis.c -= col_width;
col_width = nscoord_MAX;
} else {
float c = float(space) / float(basis.c);
basis.c -= col_width;
col_width += NSToCoordRound(float(col_width) * c);
}
}
}
break;
case FLEX_FLEX_LARGE_ZERO:
NS_ASSERTION(aWidthType == BTLS_FINAL_WIDTH,
"FLEX_FLEX_LARGE_ZERO only should be hit "
"when we're setting final width.");
if (pct == 0.0f &&
!colFrame->GetHasSpecifiedCoord() &&
cellMap->GetNumCellsOriginatingInCol(col) > 0) {
NS_ASSERTION(col_width == 0 &&
colFrame->GetPrefCoord() == 0,
"Since we're in FLEX_FLEX_LARGE_ZERO case, "
"all auto-width cols should have zero pref "
"width.");
float c = float(space) / float(basis.c);
col_width += NSToCoordRound(c);
--basis.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;
}
// Only subtract from space if it's a real number.
if (space != nscoord_MAX) {
NS_ASSERTION(col_width != nscoord_MAX,
"How is col_width nscoord_MAX if space isn't?");
NS_ASSERTION(col_width_before_adjust != nscoord_MAX,
"How is col_width_before_adjust nscoord_MAX if space isn't?");
space -= col_width - col_width_before_adjust;
}
NS_ASSERTION(col_width >= colFrame->GetMinCoord(),
"assigned width smaller than min");
// Apply the new width
switch (aWidthType) {
case BTLS_MIN_WIDTH:
{
// Note: AddSpanCoords requires both a min and pref width.
// For the pref width, we'll just pass in our computed
// min width, because the real pref width will be at least
// as big
colFrame->AddSpanCoords(col_width, col_width,
aSpanHasSpecifiedWidth);
}
break;
case BTLS_PREF_WIDTH:
{
// Note: AddSpanCoords requires both a min and pref width.
// For the min width, we'll just pass in 0, because
// the real min width will be at least 0
colFrame->AddSpanCoords(0, col_width,
aSpanHasSpecifiedWidth);
}
break;
case BTLS_FINAL_WIDTH:
{
nscoord old_final = colFrame->GetFinalWidth();
colFrame->SetFinalWidth(col_width);
if (old_final != col_width)
mTableFrame->DidResizeColumns();
}
break;
}
}
NS_ASSERTION((space == 0 || space == nscoord_MAX) &&
((l2t == FLEX_PCT_LARGE)
? (-0.001f < basis.f && basis.f < 0.001f)
: (basis.c == 0 || basis.c == nscoord_MAX)),
"didn't subtract all that we added");
}
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