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09229da43e
gecko/layout/tables/BasicTableLayoutStrategy.cpp
L. David Baron 09229da43e Don't distribute percentage width from column-spanning cells to columns that have no cells originating. (Bug 810586) r=dholbert 
This makes the distribution of pref/min width and the distribution of
percentage width from column-spanning cells more consistent with each
other.  Having them inconsistent means that a column-spanning cell that
has both percentage width and minimum intrinsic width might distribute
those widths among its columns differently, which can then lead to the
percentages unnecessarily increasing the table's preferred intrinsic
width.

(It *might* also be worth fixing the FLEX_ALL_LARGE case in
DistributeWidthToColumns to also check for originating cells, since it's
now the only case that doesn't, except that we can't guarantee that
there are columns with originating cells, so it would really require
splitting that case, which is extra complexity that doesn't seem worth
it for such a rarely-hit and non-interoperable case.)

--HG--
extra : transplant_source : %80%C9z%F4%EF%18%E1y%BB%B3%E57%0C%3A%0B%92%2C%B8%83%AC
2013-01-02 22:58:05 -05:00

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
// vim:cindent:ts=4:et:sw=4:
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/*
* 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"
using namespace mozilla;
using namespace mozilla::layout;
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;
const nsStylePosition *stylePos = aFrame->GetStylePosition();
bool isQuirks = aFrame->PresContext()->CompatibilityMode() ==
eCompatibility_NavQuirks;
nscoord boxSizingToBorderEdge = 0;
if (aIsCell) {
// If aFrame is a container for font size inflation, then shrink
// wrapping inside of it should not apply font size inflation.
AutoMaybeDisableFontInflation an(aFrame);
minCoord = aFrame->GetMinWidth(aRenderingContext);
prefCoord = aFrame->GetPrefWidth(aRenderingContext);
// Until almost the end of this function, minCoord and prefCoord
// represent the box-sizing based width values (which mean they
// should include horizontal padding and border width when
// box-sizing is set to border-box).
// Note that this function returns border-box width, we add the
// outer edges near the end of this function.
// XXX Should we ignore percentage padding?
nsIFrame::IntrinsicWidthOffsetData offsets = aFrame->IntrinsicWidthOffsets(aRenderingContext);
// In quirks mode, table cell width should be content-box,
// but height should be border box.
// Because of this historic anomaly, we do not use quirk.css.
// (We can't specify one value of box-sizing for width and another
// for height).
// For this reason, we also do not use box-sizing for just one of
// them, as this may be confusing.
if (isQuirks) {
boxSizingToBorderEdge = offsets.hPadding + offsets.hBorder;
}
else {
switch (stylePos->mBoxSizing) {
case NS_STYLE_BOX_SIZING_CONTENT:
boxSizingToBorderEdge = offsets.hPadding + offsets.hBorder;
break;
case NS_STYLE_BOX_SIZING_PADDING:
minCoord += offsets.hPadding;
prefCoord += offsets.hPadding;
boxSizingToBorderEdge = offsets.hBorder;
break;
default:
// NS_STYLE_BOX_SIZING_BORDER
minCoord += offsets.hPadding + offsets.hBorder;
prefCoord += offsets.hPadding + offsets.hBorder;
break;
}
}
} else {
minCoord = 0;
prefCoord = 0;
}
float prefPercent = 0.0f;
bool hasSpecifiedWidth = false;
const nsStyleCoord &width = stylePos->mWidth;
nsStyleUnit unit = width.GetUnit();
// NOTE: We're ignoring calc() units with percentages here, for lack of a
// sensible idea for what to do with them. This means calc() with
// percentages is basically handled like 'auto' for table cells and
// columns.
if (width.ConvertsToLength()) {
hasSpecifiedWidth = true;
// Note: since ComputeWidthValue was designed to return content-box
// width, it will (in some cases) subtract the box-sizing edges.
// We prevent this unwanted behavior by calling it with
// aContentEdgeToBoxSizing and aBoxSizingToMarginEdge set to 0.
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 && isQuirks &&
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 (maxWidth.ConvertsToLength() || 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() with percentages 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 (minWidth.ConvertsToLength() || 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() with percentages on min-width just like '0'.
// XXX Should col frame have border/padding considered?
if (aIsCell) {
minCoord += boxSizingToBorderEdge;
prefCoord = NSCoordSaturatingAdd(prefCoord, boxSizingToBorderEdge);
}
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();
mozilla::AutoStackArena arena;
SpanningCellSorter spanningCells;
// Loop over the columns to consider the columns and cells *without*
// a colspan.
int32_t 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);
int32_t 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;
int32_t colSpan;
while ((item = spanningCells.GetNext(&colSpan))) {
NS_ASSERTION(colSpan > 1,
"cell should not have been put in spanning cell sorter");
do {
int32_t 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
int32_t colCount = cellMap->GetColCount();
nscoord spacing = mTableFrame->GetCellSpacingX();
nscoord add = spacing; // add (colcount + 1) * spacing for columns
// where a cell originates
for (int32_t 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();
int32_t 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,
int32_t aFirstCol,
int32_t aColCount)
{
// First loop to determine:
int32_t 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
int32_t scol, scol_end;
nsTableCellMap *cellMap = mTableFrame->GetCellMap();
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();
if (cellMap->GetNumCellsOriginatingInCol(scol) > 0) {
++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 if (cellMap->GetNumCellsOriginatingInCol(scol) > 0) {
// distribute equally when all pref widths are 0
allocatedPct = aSpanPrefPct / float(nonPctColCount);
} else {
allocatedPct = 0.0f;
}
// 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();
if (cellMap->GetNumCellsOriginatingInCol(scol) > 0) {
--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,
int32_t aFirstCol,
int32_t 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 (int32_t 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. 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
int32_t numInfiniteWidthCols = 0;
int32_t numNonSpecZeroWidthCols = 0;
int32_t 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 (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) {
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:
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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