/* -*- 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 (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. 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.Reset(); 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 }