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layout/table/
layout.rs

1/* This Source Code Form is subject to the terms of the Mozilla Public
2 * License, v. 2.0. If a copy of the MPL was not distributed with this
3 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
4
5use core::cmp::Ordering;
6use std::mem;
7use std::ops::Range;
8
9use app_units::Au;
10use atomic_refcell::AtomicRef;
11use log::warn;
12use rayon::iter::{IndexedParallelIterator, IntoParallelRefIterator, ParallelIterator};
13use servo_arc::Arc;
14use strum::{EnumIter, IntoEnumIterator};
15use style::Zero;
16use style::computed_values::border_collapse::T as BorderCollapse;
17use style::computed_values::box_sizing::T as BoxSizing;
18use style::computed_values::caption_side::T as CaptionSide;
19use style::computed_values::empty_cells::T as EmptyCells;
20use style::computed_values::position::T as Position;
21use style::computed_values::table_layout::T as TableLayoutMode;
22use style::computed_values::visibility::T as Visibility;
23use style::properties::ComputedValues;
24use style::values::computed::{
25    AlignmentBaseline, BaselineShift, BorderStyle, LengthPercentage as ComputedLengthPercentage,
26    Percentage,
27};
28use style::values::generics::box_::BaselineShiftKeyword;
29
30use super::{
31    ArcRefCell, CollapsedBorder, CollapsedBorderLine, SpecificTableGridInfo, Table, TableCaption,
32    TableLayoutStyle, TableSlot, TableSlotCell, TableSlotCoordinates, TableTrack, TableTrackGroup,
33};
34use crate::context::LayoutContext;
35use crate::dom::WeakLayoutBox;
36use crate::formatting_contexts::Baselines;
37use crate::fragment_tree::{
38    BoxFragment, CollapsedBlockMargins, ExtraBackground, Fragment, FragmentFlags,
39    PositioningFragment, SpecificLayoutInfo,
40};
41use crate::geom::{
42    LogicalRect, LogicalSides, LogicalSides1D, LogicalVec2, PhysicalPoint, PhysicalRect,
43    PhysicalSides, PhysicalVec, ToLogical, ToLogicalWithContainingBlock,
44};
45use crate::layout_box_base::IndependentFormattingContextLayoutResult;
46use crate::positioned::{PositioningContext, PositioningContextLength, relative_adjustement};
47use crate::sizing::{
48    ComputeInlineContentSizes, ContentSizes, InlineContentSizesResult, LazySize, Size,
49    SizeConstraint,
50};
51use crate::style_ext::{
52    BorderStyleColor, Clamp, ComputedValuesExt, LayoutStyle, PaddingBorderMargin,
53};
54use crate::table::WeakTableLevelBox;
55use crate::{
56    ConstraintSpace, ContainingBlock, ContainingBlockSize, IndefiniteContainingBlock, WritingMode,
57};
58
59#[derive(PartialEq)]
60enum CellContentAlignment {
61    Top,
62    Bottom,
63    Middle,
64    Baseline,
65}
66
67/// A result of a final or speculative layout of a single cell in
68/// the table. Note that this is only done for slots that are not
69/// covered by spans or empty.
70struct CellLayout {
71    layout: IndependentFormattingContextLayoutResult,
72    padding: LogicalSides<Au>,
73    border: LogicalSides<Au>,
74    positioning_context: PositioningContext,
75}
76
77impl CellLayout {
78    fn ascent(&self) -> Au {
79        self.layout
80            .baselines
81            .first
82            .unwrap_or(self.layout.content_block_size)
83    }
84
85    /// The block size of this laid out cell including its border and padding.
86    fn outer_block_size(&self) -> Au {
87        self.layout.content_block_size + self.border.block_sum() + self.padding.block_sum()
88    }
89
90    /// Whether the cell has no in-flow or out-of-flow contents, other than collapsed whitespace.
91    /// Note this logic differs from 'empty-cells', which counts abspos contents as empty.
92    fn is_empty(&self) -> bool {
93        self.layout.fragments.is_empty()
94    }
95
96    /// Whether the cell is considered empty for the purpose of the 'empty-cells' property.
97    fn is_empty_for_empty_cells(&self) -> bool {
98        self.layout
99            .fragments
100            .iter()
101            .all(|fragment| matches!(fragment, Fragment::AbsoluteOrFixedPositionedPlaceholder(_)))
102    }
103}
104
105/// Information stored during the layout of rows.
106#[derive(Clone, Debug, Default)]
107struct RowLayout {
108    constrained: bool,
109    has_cell_with_span_greater_than_one: bool,
110    percent: Percentage,
111}
112
113/// Information stored during the layout of columns.
114#[derive(Clone, Debug, Default)]
115struct ColumnLayout {
116    constrained: bool,
117    has_originating_cells: bool,
118    content_sizes: ContentSizes,
119    percentage: Option<Percentage>,
120}
121
122fn max_two_optional_percentages(
123    a: Option<Percentage>,
124    b: Option<Percentage>,
125) -> Option<Percentage> {
126    match (a, b) {
127        (Some(a), Some(b)) => Some(Percentage(a.0.max(b.0))),
128        _ => a.or(b),
129    }
130}
131
132impl ColumnLayout {
133    fn incorporate_cell_measure(&mut self, cell_measure: &CellOrTrackMeasure) {
134        self.content_sizes.max_assign(cell_measure.content_sizes);
135        self.percentage = max_two_optional_percentages(self.percentage, cell_measure.percentage);
136    }
137}
138
139impl CollapsedBorder {
140    fn new(style_color: BorderStyleColor, width: Au) -> Self {
141        Self { style_color, width }
142    }
143
144    fn from_layout_style(
145        layout_style: &LayoutStyle,
146        writing_mode: WritingMode,
147    ) -> LogicalSides<Self> {
148        let border_style_color = layout_style.style().border_style_color(writing_mode);
149        let border_width = layout_style.border_width(writing_mode);
150        LogicalSides {
151            inline_start: Self::new(border_style_color.inline_start, border_width.inline_start),
152            inline_end: Self::new(border_style_color.inline_end, border_width.inline_end),
153            block_start: Self::new(border_style_color.block_start, border_width.block_start),
154            block_end: Self::new(border_style_color.block_end, border_width.block_end),
155        }
156    }
157
158    fn max_assign(&mut self, other: &Self) {
159        if *self < *other {
160            *self = other.clone();
161        }
162    }
163
164    fn max_assign_to_slice(&self, slice: &mut [CollapsedBorder]) {
165        for collapsed_border in slice {
166            collapsed_border.max_assign(self)
167        }
168    }
169
170    fn hide(&mut self) {
171        self.style_color = BorderStyleColor::hidden();
172        self.width = Au::zero();
173    }
174}
175
176/// <https://drafts.csswg.org/css-tables/#border-specificity>
177/// > Given two borders styles, the border style having the most specificity is the border style which…
178/// > 1. … has the value "hidden" as border-style, if only one does
179/// > 2. … has the biggest border-width, once converted into css pixels
180/// > 3. … has the border-style which comes first in the following list:
181/// >    double, solid, dashed, dotted, ridge, outset, groove, inset, none
182impl PartialOrd for CollapsedBorder {
183    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
184        let is_hidden = |border: &Self| border.style_color.style == BorderStyle::Hidden;
185        let candidate = (is_hidden(self).cmp(&is_hidden(other)))
186            .then_with(|| self.width.cmp(&other.width))
187            .then_with(|| self.style_color.style.cmp(&other.style_color.style));
188        if !candidate.is_eq() || self.style_color.color == other.style_color.color {
189            Some(candidate)
190        } else {
191            None
192        }
193    }
194}
195
196impl Eq for CollapsedBorder {}
197
198type CollapsedBorders = LogicalVec2<Vec<CollapsedBorderLine>>;
199
200/// A helper struct that performs the layout of the box tree version
201/// of a table into the fragment tree version. This implements
202/// <https://drafts.csswg.org/css-tables/#table-layout-algorithm>
203pub(crate) struct TableLayout<'a> {
204    table: &'a Table,
205    pbm: PaddingBorderMargin,
206    rows: Vec<RowLayout>,
207    columns: Vec<ColumnLayout>,
208    cell_measures: Vec<Vec<LogicalVec2<CellOrTrackMeasure>>>,
209    /// The calculated width of the table, including space for the grid and also for any
210    /// captions.
211    table_width: Au,
212    /// The table width minus the total horizontal border spacing (if any). This is the
213    /// width that we will be able to allocate to the columns.
214    assignable_width: Au,
215    final_table_height: Au,
216    distributed_column_widths: Vec<Au>,
217    row_sizes: Vec<Au>,
218    /// The accumulated baseline of each row, relative to the top of the row.
219    row_baselines: Vec<Au>,
220    cells_laid_out: Vec<Vec<Option<CellLayout>>>,
221    basis_for_cell_padding_percentage: Au,
222    /// Information about collapsed borders.
223    collapsed_borders: Option<CollapsedBorders>,
224    is_in_fixed_mode: bool,
225}
226
227#[derive(Clone, Debug)]
228struct CellOrTrackMeasure {
229    content_sizes: ContentSizes,
230    percentage: Option<Percentage>,
231}
232
233impl Zero for CellOrTrackMeasure {
234    fn zero() -> Self {
235        Self {
236            content_sizes: ContentSizes::zero(),
237            percentage: None,
238        }
239    }
240
241    fn is_zero(&self) -> bool {
242        self.content_sizes.is_zero() && self.percentage.is_none()
243    }
244}
245
246impl<'a> TableLayout<'a> {
247    fn new(table: &'a Table) -> TableLayout<'a> {
248        // The CSSWG resolved that `auto` and `max-content` inline sizes prevent fixed table mode.
249        // <https://github.com/w3c/csswg-drafts/issues/10937>
250        let style = &table.style;
251        let is_in_fixed_mode = style.get_table().table_layout == TableLayoutMode::Fixed &&
252            !matches!(
253                style.box_size(style.writing_mode).inline,
254                Size::Initial | Size::MaxContent
255            );
256        Self {
257            table,
258            pbm: PaddingBorderMargin::zero(),
259            rows: Vec::new(),
260            columns: Vec::new(),
261            cell_measures: Vec::new(),
262            table_width: Au::zero(),
263            assignable_width: Au::zero(),
264            final_table_height: Au::zero(),
265            distributed_column_widths: Vec::new(),
266            row_sizes: Vec::new(),
267            row_baselines: Vec::new(),
268            cells_laid_out: Vec::new(),
269            basis_for_cell_padding_percentage: Au::zero(),
270            collapsed_borders: None,
271            is_in_fixed_mode,
272        }
273    }
274
275    /// This is an implementation of *Computing Cell Measures* from
276    /// <https://drafts.csswg.org/css-tables/#computing-cell-measures>.
277    pub(crate) fn compute_cell_measures(
278        &mut self,
279        layout_context: &LayoutContext,
280        writing_mode: WritingMode,
281    ) {
282        let row_measures = vec![LogicalVec2::zero(); self.table.size.width];
283        self.cell_measures = vec![row_measures; self.table.size.height];
284
285        for row_index in 0..self.table.size.height {
286            for column_index in 0..self.table.size.width {
287                let cell = match self.table.slots[row_index][column_index] {
288                    TableSlot::Cell(ref cell) => cell,
289                    _ => continue,
290                }
291                .borrow();
292
293                let layout_style = cell.context.layout_style();
294                let padding = layout_style
295                    .padding(writing_mode)
296                    .percentages_relative_to(Au::zero());
297                let border = self
298                    .get_collapsed_border_widths_for_area(LogicalSides {
299                        inline_start: column_index,
300                        inline_end: column_index + cell.colspan,
301                        block_start: row_index,
302                        block_end: row_index + cell.rowspan,
303                    })
304                    .unwrap_or_else(|| layout_style.border_width(writing_mode));
305
306                let padding_border_sums = LogicalVec2 {
307                    inline: padding.inline_sum() + border.inline_sum(),
308                    block: padding.block_sum() + border.block_sum(),
309                };
310
311                let CellOrColumnOuterSizes {
312                    preferred: preferred_size,
313                    min: min_size,
314                    max: max_size,
315                    percentage: percentage_size,
316                } = CellOrColumnOuterSizes::new(
317                    &cell.context.base.style,
318                    writing_mode,
319                    &padding_border_sums,
320                    self.is_in_fixed_mode,
321                );
322
323                // <https://drafts.csswg.org/css-tables/#in-fixed-mode>
324                // > When a table-root is laid out in fixed mode, the content of its table-cells is ignored
325                // > for the purpose of width computation, the aggregation algorithm for column sizing considers
326                // > only table-cells belonging to the first row track
327                let inline_measure = if self.is_in_fixed_mode {
328                    if row_index > 0 {
329                        CellOrTrackMeasure::zero()
330                    } else {
331                        CellOrTrackMeasure {
332                            content_sizes: preferred_size.inline.into(),
333                            percentage: percentage_size.inline,
334                        }
335                    }
336                } else {
337                    let constraint_space = ConstraintSpace::new(
338                        SizeConstraint::default(),
339                        &cell.context.base.style,
340                        cell.context.preferred_aspect_ratio(&padding_border_sums),
341                    );
342                    let inline_content_sizes = cell
343                        .context
344                        .inline_content_sizes(layout_context, &constraint_space)
345                        .sizes +
346                        padding_border_sums.inline.into();
347                    assert!(
348                        inline_content_sizes.max_content >= inline_content_sizes.min_content,
349                        "the max-content size should never be smaller than the min-content size"
350                    );
351
352                    // These formulas differ from the spec, but seem to match Gecko and Blink.
353                    let outer_min_content_width = inline_content_sizes
354                        .min_content
355                        .clamp_between_extremums(min_size.inline, max_size.inline);
356                    let outer_max_content_width = if self.columns[column_index].constrained {
357                        inline_content_sizes
358                            .min_content
359                            .max(preferred_size.inline)
360                            .clamp_between_extremums(min_size.inline, max_size.inline)
361                    } else {
362                        inline_content_sizes
363                            .max_content
364                            .max(preferred_size.inline)
365                            .clamp_between_extremums(min_size.inline, max_size.inline)
366                    };
367                    assert!(outer_min_content_width <= outer_max_content_width);
368
369                    CellOrTrackMeasure {
370                        content_sizes: ContentSizes {
371                            min_content: outer_min_content_width,
372                            max_content: outer_max_content_width,
373                        },
374                        percentage: percentage_size.inline,
375                    }
376                };
377
378                // This measure doesn't take into account the `min-content` and `max-content` sizes.
379                // These sizes are incorporated after the first row layout pass, when the block size
380                // of the layout is known.
381                let block_measure = CellOrTrackMeasure {
382                    content_sizes: preferred_size.block.into(),
383                    percentage: percentage_size.block,
384                };
385
386                self.cell_measures[row_index][column_index] = LogicalVec2 {
387                    inline: inline_measure,
388                    block: block_measure,
389                };
390            }
391        }
392    }
393
394    /// Compute the constrainedness of every column in the table.
395    ///
396    /// > A column is constrained if its corresponding table-column-group (if any), its
397    /// > corresponding table-column (if any), or any of the cells spanning only that
398    /// > column has a computed width that is not "auto", and is not a percentage.
399    fn compute_track_constrainedness_and_has_originating_cells(
400        &mut self,
401        writing_mode: WritingMode,
402    ) {
403        self.rows = vec![RowLayout::default(); self.table.size.height];
404        self.columns = vec![ColumnLayout::default(); self.table.size.width];
405
406        let is_length = |size: &Size<ComputedLengthPercentage>| {
407            size.to_numeric().is_some_and(|size| !size.has_percentage())
408        };
409
410        for column_index in 0..self.table.size.width {
411            if let Some(column) = self.table.columns.get(column_index) {
412                let column = column.borrow();
413                if is_length(&column.base.style.box_size(writing_mode).inline) {
414                    self.columns[column_index].constrained = true;
415                    continue;
416                }
417                if let Some(column_group_index) = column.group_index {
418                    let column_group = self.table.column_groups[column_group_index].borrow();
419                    if is_length(&column_group.base.style.box_size(writing_mode).inline) {
420                        self.columns[column_index].constrained = true;
421                        continue;
422                    }
423                }
424            }
425        }
426
427        for row_index in 0..self.table.size.height {
428            if let Some(row) = self.table.rows.get(row_index) {
429                let row = row.borrow();
430                if is_length(&row.base.style.box_size(writing_mode).block) {
431                    self.rows[row_index].constrained = true;
432                    continue;
433                }
434                if let Some(row_group_index) = row.group_index {
435                    let row_group = self.table.row_groups[row_group_index].borrow();
436                    if is_length(&row_group.base.style.box_size(writing_mode).block) {
437                        self.rows[row_index].constrained = true;
438                        continue;
439                    }
440                }
441            }
442        }
443
444        for column_index in 0..self.table.size.width {
445            for row_index in 0..self.table.size.height {
446                let coords = TableSlotCoordinates::new(column_index, row_index);
447                let cell_constrained = match self.table.resolve_first_cell(coords) {
448                    Some(cell) if cell.colspan == 1 => cell
449                        .context
450                        .base
451                        .style
452                        .box_size(writing_mode)
453                        .map(is_length),
454                    _ => LogicalVec2::default(),
455                };
456
457                let rowspan_greater_than_1 = match self.table.slots[row_index][column_index] {
458                    TableSlot::Cell(ref cell) => cell.borrow().rowspan > 1,
459                    _ => false,
460                };
461
462                self.rows[row_index].has_cell_with_span_greater_than_one |= rowspan_greater_than_1;
463                self.rows[row_index].constrained |= cell_constrained.block;
464
465                let has_originating_cell =
466                    matches!(self.table.get_slot(coords), Some(TableSlot::Cell(_)));
467                self.columns[column_index].has_originating_cells |= has_originating_cell;
468                self.columns[column_index].constrained |= cell_constrained.inline;
469            }
470        }
471    }
472
473    /// This is an implementation of *Computing Column Measures* from
474    /// <https://drafts.csswg.org/css-tables/#computing-column-measures>.
475    fn compute_column_measures(&mut self, writing_mode: WritingMode) {
476        // Compute the column measures only taking into account cells with colspan == 1.
477        // This is the base case that will be used to iteratively account for cells with
478        // larger colspans afterward.
479        //
480        // > min-content width of a column based on cells of span up to 1
481        // >     The largest of:
482        // >         - the width specified for the column:
483        // >               - the outer min-content width of its corresponding table-column,
484        // >                 if any (and not auto)
485        // >               - the outer min-content width of its corresponding table-column-group, if any
486        // >               - or 0, if there is none
487        // >         - the outer min-content width of each cell that spans the column whose colSpan
488        // >           is 1 (or just the one in the first row in fixed mode) or 0 if there is none
489        // >
490        // > max-content width of a column based on cells of span up to 1
491        // >     The largest of:
492        // >         - the outer max-content width of its corresponding
493        // >           table-column-group, if any
494        // >         - the outer max-content width of its corresponding table-column, if any
495        // >         - the outer max-content width of each cell that spans the column
496        // >           whose colSpan is 1 (or just the one in the first row if in fixed mode) or 0
497        // >           if there is no such cell
498        // >
499        // > intrinsic percentage width of a column based on cells of span up to 1
500        // >     The largest of the percentage contributions of each cell that spans the column whose colSpan is
501        // >     1, of its corresponding table-column (if any), and of its corresponding table-column-group (if
502        // >     any)
503        //
504        // TODO: Take into account `table-column` and `table-column-group` lengths.
505        // TODO: Take into account changes to this computation for fixed table layout.
506        let mut colspan_cell_constraints = Vec::new();
507        for column_index in 0..self.table.size.width {
508            let column = &mut self.columns[column_index];
509
510            let column_measure = self.table.get_column_measure_for_column_at_index(
511                writing_mode,
512                column_index,
513                self.is_in_fixed_mode,
514            );
515            column.content_sizes = column_measure.content_sizes;
516            column.percentage = column_measure.percentage;
517
518            for row_index in 0..self.table.size.height {
519                let coords = TableSlotCoordinates::new(column_index, row_index);
520                let cell_measure = &self.cell_measures[row_index][column_index].inline;
521
522                let cell = match self.table.get_slot(coords) {
523                    Some(TableSlot::Cell(cell)) => cell,
524                    _ => continue,
525                }
526                .borrow();
527
528                if cell.colspan != 1 {
529                    colspan_cell_constraints.push(ColspanToDistribute {
530                        starting_column: column_index,
531                        span: cell.colspan,
532                        content_sizes: cell_measure.content_sizes,
533                        percentage: cell_measure.percentage,
534                    });
535                    continue;
536                }
537
538                // This takes the max of `min_content`, `max_content`, and
539                // intrinsic percentage width as described above.
540                column.incorporate_cell_measure(cell_measure);
541            }
542        }
543
544        // Sort the colspanned cell constraints by their span and starting column.
545        colspan_cell_constraints.sort_by(ColspanToDistribute::comparison_for_sort);
546
547        // Distribute constraints from cells with colspan != 1 to their component columns.
548        self.distribute_colspanned_cells_to_columns(colspan_cell_constraints);
549
550        // > intrinsic percentage width of a column:
551        // > the smaller of:
552        // >   * the intrinsic percentage width of the column based on cells of span up to N,
553        // >     where N is the number of columns in the table
554        // >   * 100% minus the sum of the intrinsic percentage width of all prior columns in
555        // >     the table (further left when direction is "ltr" (right for "rtl"))
556        let mut total_intrinsic_percentage_width = 0.;
557        for column in self.columns.iter_mut() {
558            if let Some(ref mut percentage) = column.percentage {
559                let final_intrinsic_percentage_width =
560                    percentage.0.min(1. - total_intrinsic_percentage_width);
561                total_intrinsic_percentage_width += final_intrinsic_percentage_width;
562                *percentage = Percentage(final_intrinsic_percentage_width);
563            }
564        }
565    }
566
567    fn distribute_colspanned_cells_to_columns(
568        &mut self,
569        colspan_cell_constraints: Vec<ColspanToDistribute>,
570    ) {
571        for colspan_cell_constraints in colspan_cell_constraints {
572            self.distribute_colspanned_cell_to_columns(colspan_cell_constraints);
573        }
574    }
575
576    /// Distribute the inline size from a cell with colspan != 1 to the columns that it spans.
577    /// This is heavily inspired by the approach that Chromium takes in redistributing colspan
578    /// cells' inline size to columns (`DistributeColspanCellToColumnsAuto` in
579    /// `blink/renderer/core/layout/table/table_layout_utils.cc`).
580    fn distribute_colspanned_cell_to_columns(
581        &mut self,
582        colspan_cell_constraints: ColspanToDistribute,
583    ) {
584        let border_spacing = self.table.border_spacing().inline;
585        let column_range = colspan_cell_constraints.range();
586        let column_count = column_range.len();
587        let total_border_spacing =
588            border_spacing.scale_by((colspan_cell_constraints.span - 1) as f32);
589
590        let mut percent_columns_count = 0;
591        let mut columns_percent_sum = 0.;
592        let mut columns_non_percent_max_inline_size_sum = Au::zero();
593        for column in self.columns[column_range.clone()].iter() {
594            if let Some(percentage) = column.percentage {
595                percent_columns_count += 1;
596                columns_percent_sum += percentage.0;
597            } else {
598                columns_non_percent_max_inline_size_sum += column.content_sizes.max_content;
599            }
600        }
601
602        let colspan_percentage = colspan_cell_constraints.percentage.unwrap_or_default();
603        let surplus_percent = colspan_percentage.0 - columns_percent_sum;
604        if surplus_percent > 0. && column_count > percent_columns_count {
605            for column in self.columns[column_range.clone()].iter_mut() {
606                if column.percentage.is_some() {
607                    continue;
608                }
609
610                let ratio = if columns_non_percent_max_inline_size_sum.is_zero() {
611                    1. / ((column_count - percent_columns_count) as f32)
612                } else {
613                    column.content_sizes.max_content.to_f32_px() /
614                        columns_non_percent_max_inline_size_sum.to_f32_px()
615                };
616                column.percentage = Some(Percentage(surplus_percent * ratio));
617            }
618        }
619
620        let colspan_cell_min_size = (colspan_cell_constraints.content_sizes.min_content -
621            total_border_spacing)
622            .max(Au::zero());
623        let distributed_minimum =
624            Self::distribute_width_to_columns(colspan_cell_min_size, &self.columns[column_range]);
625        {
626            let column_span = &mut self.columns[colspan_cell_constraints.range()];
627            for (column, minimum_size) in column_span.iter_mut().zip(distributed_minimum) {
628                column.content_sizes.min_content.max_assign(minimum_size);
629            }
630        }
631
632        let colspan_cell_max_size = (colspan_cell_constraints.content_sizes.max_content -
633            total_border_spacing)
634            .max(Au::zero());
635        let distributed_maximum = Self::distribute_width_to_columns(
636            colspan_cell_max_size,
637            &self.columns[colspan_cell_constraints.range()],
638        );
639        {
640            let column_span = &mut self.columns[colspan_cell_constraints.range()];
641            for (column, maximum_size) in column_span.iter_mut().zip(distributed_maximum) {
642                column
643                    .content_sizes
644                    .max_content
645                    .max_assign(maximum_size.max(column.content_sizes.min_content));
646            }
647        }
648    }
649
650    fn compute_measures(&mut self, layout_context: &LayoutContext, writing_mode: WritingMode) {
651        self.compute_track_constrainedness_and_has_originating_cells(writing_mode);
652        self.compute_cell_measures(layout_context, writing_mode);
653        self.compute_column_measures(writing_mode);
654    }
655
656    /// Compute the GRIDMIN and GRIDMAX.
657    fn compute_grid_min_max(&self) -> ContentSizes {
658        // https://drafts.csswg.org/css-tables/#gridmin:
659        // > The row/column-grid width minimum (GRIDMIN) width is the sum of the min-content width of
660        // > all the columns plus cell spacing or borders.
661        // https://drafts.csswg.org/css-tables/#gridmax:
662        // > The row/column-grid width maximum (GRIDMAX) width is the sum of the max-content width of
663        // > all the columns plus cell spacing or borders.
664        //
665        // The specification doesn't say what to do with columns with percentages, so we follow the
666        // approach that LayoutNG takes here. We try to figure out the size contribution
667        // of the percentage columns, by working backward to find the calculated
668        // percentage of non-percent columns and using that to calculate the size of the
669        // percent columns.
670        let mut largest_percentage_column_max_size = Au::zero();
671        let mut percent_sum = 0.;
672        let mut non_percent_columns_max_sum = Au::zero();
673        let mut grid_min_max = ContentSizes::zero();
674        for column in self.columns.iter() {
675            match column.percentage {
676                Some(percentage) if !percentage.is_zero() => {
677                    largest_percentage_column_max_size.max_assign(
678                        column
679                            .content_sizes
680                            .max_content
681                            .scale_by(1.0 / percentage.0),
682                    );
683                    percent_sum += percentage.0;
684                },
685                _ => {
686                    non_percent_columns_max_sum += column.content_sizes.max_content;
687                },
688            }
689
690            grid_min_max += column.content_sizes;
691        }
692
693        grid_min_max
694            .max_content
695            .max_assign(largest_percentage_column_max_size);
696
697        // Do not take into account percentage of columns when this table is a descendant
698        // of a flex, grid, or table container. These modes with percentage columns can
699        // cause inline width to become infinitely wide.
700        if !percent_sum.is_zero() &&
701            self.table
702                .percentage_columns_allowed_for_inline_content_sizes
703        {
704            let total_inline_size =
705                non_percent_columns_max_sum.scale_by(1.0 / (1.0 - percent_sum.min(1.0)));
706            grid_min_max.max_content.max_assign(total_inline_size);
707        }
708
709        assert!(
710            grid_min_max.min_content <= grid_min_max.max_content,
711            "GRIDMAX should never be smaller than GRIDMIN {:?}",
712            grid_min_max
713        );
714
715        let inline_border_spacing = self.table.total_border_spacing().inline;
716        grid_min_max.min_content += inline_border_spacing;
717        grid_min_max.max_content += inline_border_spacing;
718        grid_min_max
719    }
720
721    /// Compute CAPMIN: <https://drafts.csswg.org/css-tables/#capmin>
722    fn compute_caption_minimum_inline_size(&self, layout_context: &LayoutContext) -> Au {
723        let containing_block = IndefiniteContainingBlock {
724            size: LogicalVec2::default(),
725            style: &self.table.style,
726        };
727        self.table
728            .captions
729            .iter()
730            .map(|caption| {
731                caption
732                    .borrow()
733                    .context
734                    .outer_inline_content_sizes(
735                        layout_context,
736                        &containing_block,
737                        &LogicalVec2::zero(),
738                        false, /* auto_block_size_stretches_to_containing_block */
739                        false, /* skippable_for_block_percentage_quirk */
740                    )
741                    .sizes
742                    .min_content
743            })
744            .max()
745            .unwrap_or_default()
746    }
747
748    fn compute_table_width(&mut self, containing_block_for_children: &ContainingBlock) {
749        // This assumes that the parent formatting context computed the correct inline size
750        // of the table, by enforcing its min-content size as a minimum.
751        // This should be roughly equivalent to what the spec calls "used width of a table".
752        // https://drafts.csswg.org/css-tables/#used-width-of-table
753        self.table_width = containing_block_for_children.size.inline;
754
755        // > The assignable table width is the used width of the table minus the total horizontal
756        // > border spacing (if any). This is the width that we will be able to allocate to the
757        // > columns.
758        self.assignable_width = self.table_width - self.table.total_border_spacing().inline;
759
760        // This is the amount that we will use to resolve percentages in the padding of cells.
761        // It matches what Gecko and Blink do, though they disagree when there is a big caption.
762        self.basis_for_cell_padding_percentage =
763            self.table_width - self.table.border_spacing().inline * 2;
764    }
765
766    /// Distribute width to columns, performing step 2.4 of table layout from
767    /// <https://drafts.csswg.org/css-tables/#table-layout-algorithm>.
768    fn distribute_width_to_columns(target_inline_size: Au, columns: &[ColumnLayout]) -> Vec<Au> {
769        // No need to do anything if there is no column.
770        // Note that tables without rows may still have columns.
771        if columns.is_empty() {
772            return Vec::new();
773        }
774
775        // > First, each column of the table is assigned a sizing type:
776        // >  * percent-column: a column whose any constraint is defined to use a percentage only
777        // >                    (with a value different from 0%)
778        // >  * pixel-column: column whose any constraint is defined to use a defined length only
779        // >                  (and is not a percent-column)
780        // >  * auto-column: any other column
781        // >
782        // > Then, valid sizing methods are to be assigned to the columns by sizing type, yielding
783        // > the following sizing-guesses:
784        // >
785        // > * The min-content sizing-guess is the set of column width assignments where
786        // >   each column is assigned its min-content width.
787        // > * The min-content-percentage sizing-guess is the set of column width assignments where:
788        // >       * each percent-column is assigned the larger of:
789        // >           * its intrinsic percentage width times the assignable width and
790        // >           * its min-content width.
791        // >       * all other columns are assigned their min-content width.
792        // > * The min-content-specified sizing-guess is the set of column width assignments where:
793        // >       * each percent-column is assigned the larger of:
794        // >           * its intrinsic percentage width times the assignable width and
795        // >           * its min-content width
796        // >       * any other column that is constrained is assigned its max-content width
797        // >       * all other columns are assigned their min-content width.
798        // > * The max-content sizing-guess is the set of column width assignments where:
799        // >       * each percent-column is assigned the larger of:
800        // >           * its intrinsic percentage width times the assignable width and
801        // >           * its min-content width
802        // >       * all other columns are assigned their max-content width.
803        let mut min_content_sizing_guesses = Vec::new();
804        let mut min_content_percentage_sizing_guesses = Vec::new();
805        let mut min_content_specified_sizing_guesses = Vec::new();
806        let mut max_content_sizing_guesses = Vec::new();
807
808        for column in columns {
809            let min_content_width = column.content_sizes.min_content;
810            let max_content_width = column.content_sizes.max_content;
811            let constrained = column.constrained;
812
813            let (
814                min_content_percentage_sizing_guess,
815                min_content_specified_sizing_guess,
816                max_content_sizing_guess,
817            ) = if let Some(percentage) = column.percentage {
818                let resolved = target_inline_size.scale_by(percentage.0);
819                let percent_guess = min_content_width.max(resolved);
820                (percent_guess, percent_guess, percent_guess)
821            } else if constrained {
822                (min_content_width, max_content_width, max_content_width)
823            } else {
824                (min_content_width, min_content_width, max_content_width)
825            };
826
827            min_content_sizing_guesses.push(min_content_width);
828            min_content_percentage_sizing_guesses.push(min_content_percentage_sizing_guess);
829            min_content_specified_sizing_guesses.push(min_content_specified_sizing_guess);
830            max_content_sizing_guesses.push(max_content_sizing_guess);
831        }
832
833        // > If the assignable table width is less than or equal to the max-content sizing-guess, the
834        // > used widths of the columns must be the linear combination (with weights adding to 1) of
835        // > the two consecutive sizing-guesses whose width sums bound the available width.
836        //
837        // > Otherwise, the used widths of the columns are the result of starting from the max-content
838        // > sizing-guess and distributing the excess width to the columns of the table according to
839        // > the rules for distributing excess width to columns (for used width).
840        let max_content_sizing_sum = max_content_sizing_guesses.iter().sum();
841        if target_inline_size >= max_content_sizing_sum {
842            Self::distribute_extra_width_to_columns(
843                columns,
844                &mut max_content_sizing_guesses,
845                max_content_sizing_sum,
846                target_inline_size,
847            );
848            return max_content_sizing_guesses;
849        }
850        let min_content_specified_sizing_sum = min_content_specified_sizing_guesses.iter().sum();
851        if target_inline_size == min_content_specified_sizing_sum {
852            return min_content_specified_sizing_guesses;
853        }
854        let min_content_percentage_sizing_sum = min_content_percentage_sizing_guesses.iter().sum();
855        if target_inline_size == min_content_percentage_sizing_sum {
856            return min_content_percentage_sizing_guesses;
857        }
858        let min_content_sizes_sum = min_content_sizing_guesses.iter().sum();
859        if target_inline_size <= min_content_sizes_sum {
860            return min_content_sizing_guesses;
861        }
862
863        let bounds = |sum_a, sum_b| target_inline_size > sum_a && target_inline_size < sum_b;
864
865        let blend = |a: &[Au], sum_a: Au, b: &[Au], sum_b: Au| {
866            // First convert the Au units to f64 in order to do floating point division.
867            let weight_a = (target_inline_size - sum_b).to_f64_px() / (sum_a - sum_b).to_f64_px();
868            let weight_b = 1.0 - weight_a;
869
870            let mut remaining_assignable_width = target_inline_size;
871            let mut widths: Vec<Au> = a
872                .iter()
873                .zip(b.iter())
874                .map(|(guess_a, guess_b)| {
875                    let column_width = Au::from_f64_px(
876                        guess_a.to_f64_px() * weight_a + guess_b.to_f64_px() * weight_b,
877                    );
878                    // Clamp to avoid exceeding the assignable width. This could otherwise
879                    // happen when dealing with huge values whose sum is clamped to MAX_AU.
880                    let column_width = column_width.min(remaining_assignable_width);
881                    remaining_assignable_width -= column_width;
882                    column_width
883                })
884                .collect();
885
886            if !remaining_assignable_width.is_zero() {
887                // The computations above can introduce floating-point imprecisions.
888                // Since these errors are very small (1Au), it's fine to simply adjust
889                // the first column such that the total width matches the assignable width
890                debug_assert!(
891                    remaining_assignable_width >= Au::zero(),
892                    "Sum of columns shouldn't exceed the assignable table width"
893                );
894                debug_assert!(
895                    remaining_assignable_width <= Au::new(widths.len() as i32),
896                    "A deviation of more than one Au per column is unlikely to be caused by float imprecision"
897                );
898
899                // We checked if the table had columns at the top of the function, so there
900                // always is a first column
901                widths[0] += remaining_assignable_width;
902            }
903
904            debug_assert!(widths.iter().sum::<Au>() == target_inline_size);
905
906            widths
907        };
908
909        if bounds(min_content_sizes_sum, min_content_percentage_sizing_sum) {
910            return blend(
911                &min_content_sizing_guesses,
912                min_content_sizes_sum,
913                &min_content_percentage_sizing_guesses,
914                min_content_percentage_sizing_sum,
915            );
916        }
917
918        if bounds(
919            min_content_percentage_sizing_sum,
920            min_content_specified_sizing_sum,
921        ) {
922            return blend(
923                &min_content_percentage_sizing_guesses,
924                min_content_percentage_sizing_sum,
925                &min_content_specified_sizing_guesses,
926                min_content_specified_sizing_sum,
927            );
928        }
929
930        assert!(bounds(
931            min_content_specified_sizing_sum,
932            max_content_sizing_sum
933        ));
934        blend(
935            &min_content_specified_sizing_guesses,
936            min_content_specified_sizing_sum,
937            &max_content_sizing_guesses,
938            max_content_sizing_sum,
939        )
940    }
941
942    /// This is an implementation of *Distributing excess width to columns* from
943    /// <https://drafts.csswg.org/css-tables/#distributing-width-to-columns>.
944    fn distribute_extra_width_to_columns(
945        columns: &[ColumnLayout],
946        column_sizes: &mut [Au],
947        column_sizes_sum: Au,
948        assignable_width: Au,
949    ) {
950        let all_columns = 0..columns.len();
951        let extra_inline_size = assignable_width - column_sizes_sum;
952
953        let has_originating_cells =
954            |column_index: &usize| columns[*column_index].has_originating_cells;
955        let is_constrained = |column_index: &usize| columns[*column_index].constrained;
956        let is_unconstrained = |column_index: &usize| !is_constrained(column_index);
957        let has_percent_greater_than_zero = |column_index: &usize| {
958            columns[*column_index]
959                .percentage
960                .is_some_and(|percentage| percentage.0 > 0.)
961        };
962        let has_percent_zero = |column_index: &usize| !has_percent_greater_than_zero(column_index);
963        let has_max_content =
964            |column_index: &usize| !columns[*column_index].content_sizes.max_content.is_zero();
965
966        let max_content_sum = |column_index: usize| columns[column_index].content_sizes.max_content;
967
968        // > If there are non-constrained columns that have originating cells with intrinsic
969        // > percentage width of 0% and with nonzero max-content width (aka the columns allowed to
970        // > grow by this rule), the distributed widths of the columns allowed to grow by this rule
971        // > are increased in proportion to max-content width so the total increase adds to the
972        // > excess width.
973        let unconstrained_max_content_columns = all_columns
974            .clone()
975            .filter(is_unconstrained)
976            .filter(has_originating_cells)
977            .filter(has_percent_zero)
978            .filter(has_max_content);
979        let total_max_content_width: Au = unconstrained_max_content_columns
980            .clone()
981            .map(max_content_sum)
982            .sum();
983        if !total_max_content_width.is_zero() {
984            for column_index in unconstrained_max_content_columns {
985                column_sizes[column_index] += extra_inline_size.scale_by(
986                    columns[column_index].content_sizes.max_content.to_f32_px() /
987                        total_max_content_width.to_f32_px(),
988                );
989            }
990            return;
991        }
992
993        // > Otherwise, if there are non-constrained columns that have originating cells with intrinsic
994        // > percentage width of 0% (aka the columns allowed to grow by this rule, which thanks to the
995        // > previous rule must have zero max-content width), the distributed widths of the columns
996        // > allowed to grow by this rule are increased by equal amounts so the total increase adds to
997        // > the excess width.V
998        let unconstrained_no_percent_columns = all_columns
999            .clone()
1000            .filter(is_unconstrained)
1001            .filter(has_originating_cells)
1002            .filter(has_percent_zero);
1003        let total_unconstrained_no_percent = unconstrained_no_percent_columns.clone().count();
1004        if total_unconstrained_no_percent > 0 {
1005            let extra_space_per_column =
1006                extra_inline_size.scale_by(1.0 / total_unconstrained_no_percent as f32);
1007            for column_index in unconstrained_no_percent_columns {
1008                column_sizes[column_index] += extra_space_per_column;
1009            }
1010            return;
1011        }
1012
1013        // > Otherwise, if there are constrained columns with intrinsic percentage width of 0% and
1014        // > with nonzero max-content width (aka the columns allowed to grow by this rule, which, due
1015        // > to other rules, must have originating cells), the distributed widths of the columns
1016        // > allowed to grow by this rule are increased in proportion to max-content width so the
1017        // > total increase adds to the excess width.
1018        let constrained_max_content_columns = all_columns
1019            .clone()
1020            .filter(is_constrained)
1021            .filter(has_originating_cells)
1022            .filter(has_percent_zero)
1023            .filter(has_max_content);
1024        let total_max_content_width: Au = constrained_max_content_columns
1025            .clone()
1026            .map(max_content_sum)
1027            .sum();
1028        if !total_max_content_width.is_zero() {
1029            for column_index in constrained_max_content_columns {
1030                column_sizes[column_index] += extra_inline_size.scale_by(
1031                    columns[column_index].content_sizes.max_content.to_f32_px() /
1032                        total_max_content_width.to_f32_px(),
1033                );
1034            }
1035            return;
1036        }
1037
1038        // > Otherwise, if there are columns with intrinsic percentage width greater than 0% (aka the
1039        // > columns allowed to grow by this rule, which, due to other rules, must have originating
1040        // > cells), the distributed widths of the columns allowed to grow by this rule are increased
1041        // > in proportion to intrinsic percentage width so the total increase adds to the excess
1042        // > width.
1043        let columns_with_percentage = all_columns.clone().filter(has_percent_greater_than_zero);
1044        let total_percent = columns_with_percentage
1045            .clone()
1046            .map(|column_index| columns[column_index].percentage.unwrap_or_default().0)
1047            .sum::<f32>();
1048        if total_percent > 0. {
1049            for column_index in columns_with_percentage {
1050                let column_percentage = columns[column_index].percentage.unwrap_or_default();
1051                column_sizes[column_index] +=
1052                    extra_inline_size.scale_by(column_percentage.0 / total_percent);
1053            }
1054            return;
1055        }
1056
1057        // > Otherwise, if there is any such column, the distributed widths of all columns that have
1058        // > originating cells are increased by equal amounts so the total increase adds to the excess
1059        // > width.
1060        let has_originating_cells_columns = all_columns.filter(has_originating_cells);
1061        let total_has_originating_cells = has_originating_cells_columns.clone().count();
1062        if total_has_originating_cells > 0 {
1063            let extra_space_per_column =
1064                extra_inline_size.scale_by(1.0 / total_has_originating_cells as f32);
1065            for column_index in has_originating_cells_columns {
1066                column_sizes[column_index] += extra_space_per_column;
1067            }
1068            return;
1069        }
1070
1071        // > Otherwise, the distributed widths of all columns are increased by equal amounts so the
1072        // total increase adds to the excess width.
1073        let extra_space_for_all_columns = extra_inline_size.scale_by(1.0 / columns.len() as f32);
1074        for guess in column_sizes.iter_mut() {
1075            *guess += extra_space_for_all_columns;
1076        }
1077    }
1078
1079    /// This is an implementation of *Row layout (first pass)* from
1080    /// <https://drafts.csswg.org/css-tables/#row-layout>.
1081    fn layout_cells_in_row(
1082        &mut self,
1083        layout_context: &LayoutContext,
1084        containing_block_for_table: &ContainingBlock,
1085    ) {
1086        let layout_table_slot = |coordinate: TableSlotCoordinates, slot: &TableSlot| {
1087            let TableSlot::Cell(cell) = slot else {
1088                return None;
1089            };
1090
1091            let cell = cell.borrow();
1092            let area = LogicalSides {
1093                inline_start: coordinate.x,
1094                inline_end: coordinate.x + cell.colspan,
1095                block_start: coordinate.y,
1096                block_end: coordinate.y + cell.rowspan,
1097            };
1098            let layout_style = cell.context.layout_style();
1099            let border = self
1100                .get_collapsed_border_widths_for_area(area)
1101                .unwrap_or_else(|| {
1102                    layout_style.border_width(containing_block_for_table.style.writing_mode)
1103                });
1104            let padding: LogicalSides<Au> = layout_style
1105                .padding(containing_block_for_table.style.writing_mode)
1106                .percentages_relative_to(self.basis_for_cell_padding_percentage);
1107            let padding_border_sums = LogicalVec2 {
1108                inline: padding.inline_sum() + border.inline_sum(),
1109                block: padding.block_sum() + border.block_sum(),
1110            };
1111            let border_spacing_spanned =
1112                self.table.border_spacing().inline * (cell.colspan - 1) as i32;
1113
1114            let mut total_cell_width = (coordinate.x..coordinate.x + cell.colspan)
1115                .map(|column_index| self.distributed_column_widths[column_index])
1116                .sum::<Au>() -
1117                padding_border_sums.inline +
1118                border_spacing_spanned;
1119            total_cell_width = total_cell_width.max(Au::zero());
1120
1121            let preferred_aspect_ratio = cell.context.preferred_aspect_ratio(&padding_border_sums);
1122            let containing_block_for_children = ContainingBlock {
1123                size: ContainingBlockSize {
1124                    inline: total_cell_width,
1125                    block: SizeConstraint::default(),
1126                },
1127                style: &cell.context.base.style,
1128            };
1129
1130            let mut positioning_context = PositioningContext::default();
1131            let layout = cell.context.layout(
1132                layout_context,
1133                &mut positioning_context,
1134                &containing_block_for_children,
1135                containing_block_for_table,
1136                preferred_aspect_ratio,
1137                &LazySize::intrinsic(),
1138            );
1139
1140            Some(CellLayout {
1141                layout,
1142                padding,
1143                border,
1144                positioning_context,
1145            })
1146        };
1147
1148        let job_sizes = self
1149            .table
1150            .slots
1151            .iter()
1152            .map(|row| row.iter().map(|item| item.subtree_size()).sum::<usize>());
1153        self.cells_laid_out = if layout_context.should_parallelize_layout(job_sizes) {
1154            self.table
1155                .slots
1156                .par_iter()
1157                .enumerate()
1158                .map(|(row_index, row_slots)| {
1159                    row_slots
1160                        .par_iter()
1161                        .enumerate()
1162                        .map(|(column_index, slot)| {
1163                            layout_table_slot(
1164                                TableSlotCoordinates::new(column_index, row_index),
1165                                slot,
1166                            )
1167                        })
1168                        .collect()
1169                })
1170                .collect()
1171        } else {
1172            self.table
1173                .slots
1174                .iter()
1175                .enumerate()
1176                .map(|(row_index, row_slots)| {
1177                    row_slots
1178                        .iter()
1179                        .enumerate()
1180                        .map(|(column_index, slot)| {
1181                            layout_table_slot(
1182                                TableSlotCoordinates::new(column_index, row_index),
1183                                slot,
1184                            )
1185                        })
1186                        .collect()
1187                })
1188                .collect()
1189        };
1190
1191        // Now go through all cells laid out and update the cell measure based on the size
1192        // determined during layout.
1193        for row_index in 0..self.table.size.height {
1194            for column_index in 0..self.table.size.width {
1195                let Some(layout) = &self.cells_laid_out[row_index][column_index] else {
1196                    continue;
1197                };
1198
1199                self.cell_measures[row_index][column_index]
1200                    .block
1201                    .content_sizes
1202                    .max_assign(layout.outer_block_size().into());
1203            }
1204        }
1205    }
1206
1207    /// Do the first layout of a table row, after laying out the cells themselves. This is
1208    /// more or less and implementation of <https://drafts.csswg.org/css-tables/#row-layout>.
1209    fn do_first_row_layout(&mut self, writing_mode: WritingMode) -> Vec<Au> {
1210        let mut row_sizes = (0..self.table.size.height)
1211            .map(|row_index| {
1212                let (mut max_ascent, mut max_descent, mut max_row_height) =
1213                    (Au::zero(), Au::zero(), Au::zero());
1214
1215                for column_index in 0..self.table.size.width {
1216                    let cell = match self.table.slots[row_index][column_index] {
1217                        TableSlot::Cell(ref cell) => cell,
1218                        _ => continue,
1219                    };
1220
1221                    let layout = match self.cells_laid_out[row_index][column_index] {
1222                        Some(ref layout) => layout,
1223                        None => {
1224                            warn!(
1225                                "Did not find a layout at a slot index with an originating cell."
1226                            );
1227                            continue;
1228                        },
1229                    };
1230
1231                    let cell = cell.borrow();
1232                    let outer_block_size = layout.outer_block_size();
1233                    if cell.rowspan == 1 {
1234                        max_row_height.max_assign(outer_block_size);
1235                    }
1236
1237                    if cell.content_alignment() == CellContentAlignment::Baseline {
1238                        let ascent = layout.ascent();
1239                        let border_padding_start =
1240                            layout.border.block_start + layout.padding.block_start;
1241                        let border_padding_end = layout.border.block_end + layout.padding.block_end;
1242                        max_ascent.max_assign(ascent + border_padding_start);
1243
1244                        // Only take into account the descent of this cell if doesn't span
1245                        // rows. The descent portion of the cell in cells that do span rows
1246                        // may extend into other rows.
1247                        if cell.rowspan == 1 {
1248                            max_descent.max_assign(
1249                                layout.layout.content_block_size - ascent + border_padding_end,
1250                            );
1251                        }
1252                    }
1253                }
1254                self.row_baselines.push(max_ascent);
1255                max_row_height.max(max_ascent + max_descent)
1256            })
1257            .collect::<Vec<_>>();
1258        self.calculate_row_sizes_after_first_layout(&mut row_sizes, writing_mode);
1259        row_sizes
1260    }
1261
1262    /// After doing layout of table rows, calculate final row size and distribute space across
1263    /// rowspanned cells. This follows the implementation of LayoutNG and the priority
1264    /// agorithm described at <https://github.com/w3c/csswg-drafts/issues/4418>.
1265    fn calculate_row_sizes_after_first_layout(
1266        &mut self,
1267        row_sizes: &mut [Au],
1268        writing_mode: WritingMode,
1269    ) {
1270        let mut cells_to_distribute = Vec::new();
1271        let mut total_percentage = 0.;
1272        #[expect(clippy::needless_range_loop)] // It makes sense to use it here
1273        for row_index in 0..self.table.size.height {
1274            let row_measure = self
1275                .table
1276                .get_row_measure_for_row_at_index(writing_mode, row_index);
1277            row_sizes[row_index].max_assign(row_measure.content_sizes.min_content);
1278
1279            let mut percentage = row_measure.percentage.unwrap_or_default().0;
1280            for column_index in 0..self.table.size.width {
1281                let cell_percentage = self.cell_measures[row_index][column_index]
1282                    .block
1283                    .percentage
1284                    .unwrap_or_default()
1285                    .0;
1286                percentage = percentage.max(cell_percentage);
1287
1288                let cell_measure = &self.cell_measures[row_index][column_index].block;
1289                let cell = match self.table.slots[row_index][column_index] {
1290                    TableSlot::Cell(ref cell) if cell.borrow().rowspan > 1 => cell,
1291                    TableSlot::Cell(_) => {
1292                        // If this is an originating cell, that isn't spanning, then we make sure the row is
1293                        // at least big enough to hold the cell.
1294                        row_sizes[row_index].max_assign(cell_measure.content_sizes.max_content);
1295                        continue;
1296                    },
1297                    _ => continue,
1298                };
1299
1300                cells_to_distribute.push(RowspanToDistribute {
1301                    coordinates: TableSlotCoordinates::new(column_index, row_index),
1302                    cell: cell.borrow(),
1303                    measure: cell_measure,
1304                });
1305            }
1306
1307            self.rows[row_index].percent = Percentage(percentage.min(1. - total_percentage));
1308            total_percentage += self.rows[row_index].percent.0;
1309        }
1310
1311        cells_to_distribute.sort_by(|a, b| {
1312            if a.range() == b.range() {
1313                return a
1314                    .measure
1315                    .content_sizes
1316                    .min_content
1317                    .cmp(&b.measure.content_sizes.min_content);
1318            }
1319            if a.fully_encloses(b) {
1320                return std::cmp::Ordering::Greater;
1321            }
1322            if b.fully_encloses(a) {
1323                return std::cmp::Ordering::Less;
1324            }
1325            a.coordinates.y.cmp(&b.coordinates.y)
1326        });
1327
1328        for rowspan_to_distribute in cells_to_distribute {
1329            let rows_spanned = rowspan_to_distribute.range();
1330            let current_rows_size = rows_spanned.clone().map(|index| row_sizes[index]).sum();
1331            let border_spacing_spanned =
1332                self.table.border_spacing().block * (rows_spanned.len() - 1) as i32;
1333            let excess_size = (rowspan_to_distribute.measure.content_sizes.min_content -
1334                current_rows_size -
1335                border_spacing_spanned)
1336                .max(Au::zero());
1337
1338            self.distribute_extra_size_to_rows(
1339                excess_size,
1340                rows_spanned,
1341                row_sizes,
1342                None,
1343                true, /* rowspan_distribution */
1344            );
1345        }
1346    }
1347
1348    /// An implementation of the same extra block size distribution algorithm used in
1349    /// LayoutNG and described at <https://github.com/w3c/csswg-drafts/issues/4418>.
1350    fn distribute_extra_size_to_rows(
1351        &self,
1352        mut excess_size: Au,
1353        track_range: Range<usize>,
1354        track_sizes: &mut [Au],
1355        percentage_resolution_size: Option<Au>,
1356        rowspan_distribution: bool,
1357    ) {
1358        if excess_size.is_zero() {
1359            return;
1360        }
1361
1362        let is_constrained = |track_index: &usize| self.rows[*track_index].constrained;
1363        let is_unconstrained = |track_index: &usize| !is_constrained(track_index);
1364        let is_empty: Vec<bool> = track_sizes.iter().map(|size| size.is_zero()).collect();
1365        let is_not_empty = |track_index: &usize| !is_empty[*track_index];
1366        let other_row_that_starts_a_rowspan = |track_index: &usize| {
1367            *track_index != track_range.start &&
1368                self.rows[*track_index].has_cell_with_span_greater_than_one
1369        };
1370
1371        // If we have a table height (not during rowspan distribution), first distribute to rows
1372        // that have percentage sizes proportionally to the size missing to reach the percentage
1373        // of table height required.
1374        if let Some(percentage_resolution_size) = percentage_resolution_size {
1375            let get_percent_block_size_deficit = |row_index: usize, track_size: Au| {
1376                let size_needed_for_percent =
1377                    percentage_resolution_size.scale_by(self.rows[row_index].percent.0);
1378                (size_needed_for_percent - track_size).max(Au::zero())
1379            };
1380            let percent_block_size_deficit: Au = track_range
1381                .clone()
1382                .map(|index| get_percent_block_size_deficit(index, track_sizes[index]))
1383                .sum();
1384            let percent_distributable_block_size = percent_block_size_deficit.min(excess_size);
1385            if percent_distributable_block_size > Au::zero() {
1386                for track_index in track_range.clone() {
1387                    let row_deficit =
1388                        get_percent_block_size_deficit(track_index, track_sizes[track_index]);
1389                    if row_deficit > Au::zero() {
1390                        let ratio =
1391                            row_deficit.to_f32_px() / percent_block_size_deficit.to_f32_px();
1392                        let size = percent_distributable_block_size.scale_by(ratio);
1393                        track_sizes[track_index] += size;
1394                        excess_size -= size;
1395                    }
1396                }
1397            }
1398        }
1399
1400        // If this is rowspan distribution and there are rows other than the first row that have a
1401        // cell with rowspan > 1, distribute the extra space equally to those rows.
1402        if rowspan_distribution {
1403            let rows_that_start_rowspan: Vec<usize> = track_range
1404                .clone()
1405                .filter(other_row_that_starts_a_rowspan)
1406                .collect();
1407            if !rows_that_start_rowspan.is_empty() {
1408                let scale = 1.0 / rows_that_start_rowspan.len() as f32;
1409                for track_index in rows_that_start_rowspan.iter() {
1410                    track_sizes[*track_index] += excess_size.scale_by(scale);
1411                }
1412                return;
1413            }
1414        }
1415
1416        // If there are unconstrained non-empty rows, grow them all proportionally to their current size.
1417        let unconstrained_non_empty_rows: Vec<usize> = track_range
1418            .clone()
1419            .filter(is_unconstrained)
1420            .filter(is_not_empty)
1421            .collect();
1422        if !unconstrained_non_empty_rows.is_empty() {
1423            let total_size: Au = unconstrained_non_empty_rows
1424                .iter()
1425                .map(|index| track_sizes[*index])
1426                .sum();
1427            for track_index in unconstrained_non_empty_rows.iter() {
1428                let scale = track_sizes[*track_index].to_f32_px() / total_size.to_f32_px();
1429                track_sizes[*track_index] += excess_size.scale_by(scale);
1430            }
1431            return;
1432        }
1433
1434        let (non_empty_rows, empty_rows): (Vec<usize>, Vec<usize>) =
1435            track_range.clone().partition(is_not_empty);
1436        let only_have_empty_rows = empty_rows.len() == track_range.len();
1437        if !empty_rows.is_empty() {
1438            // If this is rowspan distribution and there are only empty rows, just grow the
1439            // last one.
1440            if rowspan_distribution && only_have_empty_rows {
1441                track_sizes[*empty_rows.last().unwrap()] += excess_size;
1442                return;
1443            }
1444
1445            // Otherwise, if we only have empty rows or if all the non-empty rows are constrained,
1446            // then grow the empty rows.
1447            let non_empty_rows_all_constrained = !non_empty_rows.iter().any(is_unconstrained);
1448            if only_have_empty_rows || non_empty_rows_all_constrained {
1449                // If there are both unconstrained and constrained empty rows, only increase the
1450                // size of the unconstrained ones, otherwise increase the size of all empty rows.
1451                let mut rows_to_grow = &empty_rows;
1452                let unconstrained_empty_rows: Vec<usize> = rows_to_grow
1453                    .iter()
1454                    .copied()
1455                    .filter(is_unconstrained)
1456                    .collect();
1457                if !unconstrained_empty_rows.is_empty() {
1458                    rows_to_grow = &unconstrained_empty_rows;
1459                }
1460
1461                // All empty rows that will grow equally.
1462                let scale = 1.0 / rows_to_grow.len() as f32;
1463                for track_index in rows_to_grow.iter() {
1464                    track_sizes[*track_index] += excess_size.scale_by(scale);
1465                }
1466                return;
1467            }
1468        }
1469
1470        // If there are non-empty rows, they all grow in proportion to their current size,
1471        // whether or not they are constrained.
1472        if !non_empty_rows.is_empty() {
1473            let total_size: Au = non_empty_rows.iter().map(|index| track_sizes[*index]).sum();
1474            for track_index in non_empty_rows.iter() {
1475                let scale = track_sizes[*track_index].to_f32_px() / total_size.to_f32_px();
1476                track_sizes[*track_index] += excess_size.scale_by(scale);
1477            }
1478        }
1479    }
1480
1481    /// Given computed row sizes, compute the final block size of the table and distribute extra
1482    /// block size to table rows.
1483    fn compute_table_height_and_final_row_heights(
1484        &mut self,
1485        mut row_sizes: Vec<Au>,
1486        containing_block_for_children: &ContainingBlock,
1487    ) {
1488        // The table content height is the maximum of the computed table height from style and the
1489        // sum of computed row heights from row layout plus size from borders and spacing.
1490        // TODO: for `height: stretch`, the block size of the containing block is the available
1491        // space for the entire table wrapper, but here we are using that amount for the table grid.
1492        // Therefore, if there is a caption, this will cause overflow. Gecko and WebKit have the
1493        // same problem, but not Blink.
1494        let table_height_from_style = containing_block_for_children.size.block.definite_or_min();
1495
1496        let block_border_spacing = self.table.total_border_spacing().block;
1497        let table_height_from_rows = row_sizes.iter().sum::<Au>() + block_border_spacing;
1498        self.final_table_height = table_height_from_rows.max(table_height_from_style);
1499
1500        // If the table height is defined by the rows sizes, there is no extra space to distribute
1501        // to rows.
1502        if self.final_table_height == table_height_from_rows {
1503            self.row_sizes = row_sizes;
1504            return;
1505        }
1506
1507        // There was extra block size added to the table from the table style, so distribute this
1508        // extra space to rows using the same distribution algorithm used for distributing rowspan
1509        // space.
1510        // TODO: This should first distribute space to row groups and then to rows.
1511        self.distribute_extra_size_to_rows(
1512            self.final_table_height - table_height_from_rows,
1513            0..self.table.size.height,
1514            &mut row_sizes,
1515            Some(self.final_table_height),
1516            false, /* rowspan_distribution */
1517        );
1518        self.row_sizes = row_sizes;
1519    }
1520
1521    fn layout_caption(
1522        &self,
1523        caption: &TableCaption,
1524        layout_context: &LayoutContext,
1525        parent_positioning_context: &mut PositioningContext,
1526    ) -> BoxFragment {
1527        let containing_block = &ContainingBlock {
1528            size: ContainingBlockSize {
1529                inline: self.table_width + self.pbm.padding_border_sums.inline,
1530                block: SizeConstraint::default(),
1531            },
1532            style: &self.table.style,
1533        };
1534
1535        // The parent of a caption is the table wrapper, which establishes an independent
1536        // formatting context. Therefore, we don't ignore block margins when resolving a
1537        // stretch block size. https://drafts.csswg.org/css-sizing-4/#stretch-fit-sizing
1538        let ignore_block_margins_for_stretch = LogicalSides1D::new(false, false);
1539
1540        let mut positioning_context =
1541            PositioningContext::new_for_layout_box_base(&caption.context.base);
1542        let mut box_fragment = caption.context.layout_in_flow_block_level(
1543            layout_context,
1544            positioning_context
1545                .as_mut()
1546                .unwrap_or(parent_positioning_context),
1547            containing_block,
1548            None, /* sequential_layout_state */
1549            ignore_block_margins_for_stretch,
1550            false, /* has_inline_parent */
1551        );
1552
1553        if let Some(mut positioning_context) = positioning_context.take() {
1554            positioning_context.layout_collected_children(layout_context, &mut box_fragment);
1555            parent_positioning_context.append(positioning_context);
1556        }
1557
1558        box_fragment
1559    }
1560
1561    /// Lay out the table (grid and captions) of this [`TableLayout`] into fragments. This should
1562    /// only be be called after calling [`TableLayout.compute_measures`].
1563    #[servo_tracing::instrument(name = "Table::layout", skip_all)]
1564    fn layout(
1565        mut self,
1566        layout_context: &LayoutContext,
1567        positioning_context: &mut PositioningContext,
1568        containing_block_for_children: &ContainingBlock,
1569        containing_block_for_table: &ContainingBlock,
1570    ) -> IndependentFormattingContextLayoutResult {
1571        let table_writing_mode = containing_block_for_children.style.writing_mode;
1572        self.compute_border_collapse(table_writing_mode);
1573        let layout_style = self.table.layout_style(Some(&self));
1574
1575        self.pbm = layout_style
1576            .padding_border_margin_with_writing_mode_and_containing_block_inline_size(
1577                table_writing_mode,
1578                containing_block_for_table.size.inline,
1579            );
1580        self.compute_measures(layout_context, table_writing_mode);
1581        self.compute_table_width(containing_block_for_children);
1582
1583        // The table wrapper is the one that has the CSS properties for the grid's border and padding. This
1584        // weirdness is difficult to express in Servo's layout system. We have the wrapper size itself as if
1585        // those properties applied to it and then just account for the discrepency in sizing here. In reality,
1586        // the wrapper does not draw borders / backgrounds and all of its content (grid and captions) are
1587        // placed with a negative offset in the table wrapper's content box so that they overlap the undrawn
1588        // border / padding area.
1589        //
1590        // TODO: This is a pretty large hack. It would be nicer to actually have the grid sized properly,
1591        // but it works for now.
1592        //
1593        // Get the padding, border, and margin of the table using the inline size of the table's containing
1594        // block but in the writing of the table itself.
1595        // TODO: This is broken for orthoganol flows, because the inline size of the parent isn't necessarily
1596        // the inline size of the table.
1597        let containing_block_for_logical_conversion = ContainingBlock {
1598            size: ContainingBlockSize {
1599                inline: self.table_width,
1600                block: containing_block_for_table.size.block,
1601            },
1602            style: containing_block_for_children.style,
1603        };
1604        let offset_from_wrapper = -self.pbm.padding - self.pbm.border;
1605        let mut current_block_offset = offset_from_wrapper.block_start;
1606
1607        let mut table_layout = IndependentFormattingContextLayoutResult {
1608            fragments: Vec::new(),
1609            content_block_size: Zero::zero(),
1610            content_inline_size_for_table: None,
1611            baselines: Baselines::default(),
1612            depends_on_block_constraints: true,
1613            specific_layout_info: Some(SpecificLayoutInfo::TableWrapper),
1614            collapsible_margins_in_children: CollapsedBlockMargins::zero(),
1615        };
1616
1617        #[derive(EnumIter, PartialEq)]
1618        enum TableWrapperSection {
1619            TopCaptions,
1620            Grid,
1621            BottomCaptions,
1622        }
1623        impl TableWrapperSection {
1624            fn accepts_caption(&self, caption: &TableCaption) -> bool {
1625                match caption.context.style().get_caption_side() {
1626                    CaptionSide::Top => *self == TableWrapperSection::TopCaptions,
1627                    CaptionSide::Bottom => *self == TableWrapperSection::BottomCaptions,
1628                }
1629            }
1630        }
1631
1632        for section in TableWrapperSection::iter() {
1633            if section == TableWrapperSection::Grid {
1634                let original_positioning_context_length = positioning_context.len();
1635                let grid_fragment = self.layout_grid(
1636                    layout_context,
1637                    positioning_context,
1638                    &containing_block_for_logical_conversion,
1639                    containing_block_for_children,
1640                );
1641
1642                // Take the baseline of the grid fragment, after adjusting it to be in the coordinate system
1643                // of the table wrapper.
1644                let logical_grid_content_rect = grid_fragment
1645                    .content_rect()
1646                    .to_logical(&containing_block_for_logical_conversion);
1647                let grid_pbm = grid_fragment
1648                    .padding_border_margin()
1649                    .to_logical(table_writing_mode);
1650                table_layout.baselines = grid_fragment.baselines(table_writing_mode).offset(
1651                    current_block_offset +
1652                        logical_grid_content_rect.start_corner.block +
1653                        grid_pbm.block_start,
1654                );
1655
1656                grid_fragment.base.set_rect(
1657                    LogicalRect {
1658                        start_corner: LogicalVec2 {
1659                            inline: offset_from_wrapper.inline_start + grid_pbm.inline_start,
1660                            block: current_block_offset + grid_pbm.block_start,
1661                        },
1662                        size: grid_fragment
1663                            .base
1664                            .rect()
1665                            .size
1666                            .to_logical(table_writing_mode),
1667                    }
1668                    .as_physical(Some(&containing_block_for_logical_conversion)),
1669                );
1670
1671                current_block_offset += grid_fragment
1672                    .border_rect()
1673                    .size
1674                    .to_logical(table_writing_mode)
1675                    .block;
1676                if logical_grid_content_rect.size.inline < self.table_width {
1677                    // This can happen when collapsing columns
1678                    table_layout.content_inline_size_for_table =
1679                        Some(logical_grid_content_rect.size.inline);
1680                }
1681
1682                let grid_fragment = Fragment::Box(grid_fragment.into());
1683                positioning_context.adjust_static_position_of_hoisted_fragments(
1684                    &grid_fragment,
1685                    original_positioning_context_length,
1686                );
1687                table_layout.fragments.push(grid_fragment);
1688            } else {
1689                let caption_fragments = self.table.captions.iter().filter_map(|caption| {
1690                    let caption = caption.borrow();
1691                    if !section.accepts_caption(&caption) {
1692                        return None;
1693                    }
1694
1695                    let original_positioning_context_length = positioning_context.len();
1696                    let caption_fragment =
1697                        self.layout_caption(&caption, layout_context, positioning_context);
1698
1699                    // The caption is not placed yet. Construct a rectangle for it in the adjusted containing block
1700                    // for the table children and only then convert the result to physical geometry.
1701                    let caption_pbm = caption_fragment
1702                        .padding_border_margin()
1703                        .to_logical(table_writing_mode);
1704
1705                    let caption_style = caption_fragment.style().clone();
1706                    let caption_relative_offset = match caption_style.get_box().position {
1707                        Position::Relative => {
1708                            relative_adjustement(&caption_style, containing_block_for_children)
1709                        },
1710                        _ => LogicalVec2::zero(),
1711                    };
1712
1713                    caption_fragment.base.set_rect(
1714                        LogicalRect {
1715                            start_corner: LogicalVec2 {
1716                                inline: offset_from_wrapper.inline_start + caption_pbm.inline_start,
1717                                block: current_block_offset + caption_pbm.block_start,
1718                            } + caption_relative_offset,
1719                            size: caption_fragment
1720                                .content_rect()
1721                                .size
1722                                .to_logical(table_writing_mode),
1723                        }
1724                        .as_physical(Some(&containing_block_for_logical_conversion)),
1725                    );
1726
1727                    current_block_offset += caption_fragment
1728                        .margin_rect()
1729                        .size
1730                        .to_logical(table_writing_mode)
1731                        .block;
1732
1733                    let caption_fragment = Fragment::Box(caption_fragment.into());
1734                    positioning_context.adjust_static_position_of_hoisted_fragments(
1735                        &caption_fragment,
1736                        original_positioning_context_length,
1737                    );
1738
1739                    caption.context.base.set_fragment(caption_fragment.clone());
1740                    Some(caption_fragment)
1741                });
1742                table_layout.fragments.extend(caption_fragments);
1743            }
1744        }
1745
1746        table_layout.content_block_size = current_block_offset + offset_from_wrapper.block_end;
1747        table_layout
1748    }
1749
1750    /// Lay out the grid portion of this [`TableLayout`] into fragments. This should only be be
1751    /// called after calling [`TableLayout.compute_measures`].
1752    fn layout_grid(
1753        &mut self,
1754        layout_context: &LayoutContext,
1755        positioning_context: &mut PositioningContext,
1756        containing_block_for_logical_conversion: &ContainingBlock,
1757        containing_block_for_children: &ContainingBlock,
1758    ) -> BoxFragment {
1759        self.distributed_column_widths =
1760            Self::distribute_width_to_columns(self.assignable_width, &self.columns);
1761        self.layout_cells_in_row(layout_context, containing_block_for_children);
1762        let table_writing_mode = containing_block_for_children.style.writing_mode;
1763        let first_layout_row_heights = self.do_first_row_layout(table_writing_mode);
1764        self.compute_table_height_and_final_row_heights(
1765            first_layout_row_heights,
1766            containing_block_for_children,
1767        );
1768
1769        assert_eq!(self.table.size.height, self.row_sizes.len());
1770        assert_eq!(self.table.size.width, self.distributed_column_widths.len());
1771
1772        if self.table.size.width == 0 && self.table.size.height == 0 {
1773            let content_rect = LogicalRect {
1774                start_corner: LogicalVec2::zero(),
1775                size: LogicalVec2 {
1776                    inline: self.table_width,
1777                    block: self.final_table_height,
1778                },
1779            }
1780            .as_physical(Some(containing_block_for_logical_conversion));
1781            return BoxFragment::new(
1782                self.table.grid_base_fragment_info,
1783                self.table.grid_style.clone(),
1784                Vec::new(),
1785                content_rect,
1786                self.pbm.padding.to_physical(table_writing_mode),
1787                self.pbm.border.to_physical(table_writing_mode),
1788                PhysicalSides::zero(),
1789                self.specific_layout_info_for_grid(),
1790            );
1791        }
1792
1793        let mut table_fragments = Vec::new();
1794        let table_and_track_dimensions = TableAndTrackDimensions::new(self);
1795        self.make_fragments_for_columns_and_column_groups(
1796            &table_and_track_dimensions,
1797            &mut table_fragments,
1798        );
1799
1800        let mut baselines = Baselines::default();
1801        let mut row_group_fragment_layout = None;
1802        for row_index in 0..self.table.size.height {
1803            // From <https://drafts.csswg.org/css-align-3/#baseline-export>
1804            // > If any cells in the row participate in first baseline/last baseline alignment along
1805            // > the inline axis, the first/last baseline set of the row is generated from their
1806            // > shared alignment baseline and the row’s first available font, after alignment has
1807            // > been performed. Otherwise, the first/last baseline set of the row is synthesized from
1808            // > the lowest and highest content edges of the cells in the row. [CSS2]
1809            //
1810            // If any cell below has baseline alignment, these values will be overwritten,
1811            // but they are initialized to the content edge of the first row.
1812            if row_index == 0 {
1813                let row_end = table_and_track_dimensions
1814                    .get_row_rect(0)
1815                    .max_block_position();
1816                baselines.first = Some(row_end);
1817                baselines.last = Some(row_end);
1818            }
1819
1820            let row_is_collapsed = self.is_row_collapsed(row_index);
1821            let table_row = self.table.rows[row_index].borrow();
1822            let mut row_fragment_layout = RowFragmentLayout::new(
1823                &table_row,
1824                row_index,
1825                &table_and_track_dimensions,
1826                &self.table.style,
1827            );
1828
1829            let old_row_group_index = row_group_fragment_layout
1830                .as_ref()
1831                .map(|layout: &RowGroupFragmentLayout| layout.index);
1832            if table_row.group_index != old_row_group_index {
1833                // First create the Fragment for any existing RowGroupFragmentLayout.
1834                if let Some(old_row_group_layout) = row_group_fragment_layout.take() {
1835                    table_fragments.push(old_row_group_layout.finish(
1836                        layout_context,
1837                        positioning_context,
1838                        containing_block_for_logical_conversion,
1839                        containing_block_for_children,
1840                    ));
1841                }
1842
1843                // Then, create a new RowGroupFragmentLayout for the current and potentially subsequent rows.
1844                if let Some(new_group_index) = table_row.group_index {
1845                    row_group_fragment_layout = Some(RowGroupFragmentLayout::new(
1846                        self.table.row_groups[new_group_index].clone(),
1847                        new_group_index,
1848                        &table_and_track_dimensions,
1849                    ));
1850                }
1851            }
1852
1853            let column_indices = 0..self.table.size.width;
1854            row_fragment_layout.fragments.reserve(self.table.size.width);
1855            for column_index in column_indices {
1856                self.do_final_cell_layout(
1857                    row_index,
1858                    column_index,
1859                    &table_and_track_dimensions,
1860                    &mut baselines,
1861                    &mut row_fragment_layout,
1862                    row_group_fragment_layout.as_mut(),
1863                    positioning_context,
1864                    self.is_column_collapsed(column_index) || row_is_collapsed,
1865                );
1866            }
1867
1868            let row_fragment = row_fragment_layout.finish(
1869                layout_context,
1870                positioning_context,
1871                containing_block_for_logical_conversion,
1872                containing_block_for_children,
1873                &mut row_group_fragment_layout,
1874            );
1875
1876            match row_group_fragment_layout.as_mut() {
1877                Some(layout) => layout.fragments.push(row_fragment),
1878                None => table_fragments.push(row_fragment),
1879            }
1880        }
1881
1882        if let Some(row_group_layout) = row_group_fragment_layout.take() {
1883            table_fragments.push(row_group_layout.finish(
1884                layout_context,
1885                positioning_context,
1886                containing_block_for_logical_conversion,
1887                containing_block_for_children,
1888            ));
1889        }
1890
1891        let content_rect = LogicalRect {
1892            start_corner: LogicalVec2::zero(),
1893            size: LogicalVec2 {
1894                inline: table_and_track_dimensions.table_rect.max_inline_position(),
1895                block: table_and_track_dimensions.table_rect.max_block_position(),
1896            },
1897        }
1898        .as_physical(Some(containing_block_for_logical_conversion));
1899        BoxFragment::new(
1900            self.table.grid_base_fragment_info,
1901            self.table.grid_style.clone(),
1902            table_fragments,
1903            content_rect,
1904            self.pbm.padding.to_physical(table_writing_mode),
1905            self.pbm.border.to_physical(table_writing_mode),
1906            PhysicalSides::zero(),
1907            self.specific_layout_info_for_grid(),
1908        )
1909        .with_baselines(baselines)
1910    }
1911
1912    fn specific_layout_info_for_grid(&mut self) -> Option<SpecificLayoutInfo> {
1913        mem::take(&mut self.collapsed_borders).map(|mut collapsed_borders| {
1914            // TODO: It would probably be better to use `TableAndTrackDimensions`, since that
1915            // has already taken care of collapsed tracks and knows the final track positions.
1916            let mut track_sizes = LogicalVec2 {
1917                inline: mem::take(&mut self.distributed_column_widths),
1918                block: mem::take(&mut self.row_sizes),
1919            };
1920            for (column_index, column_size) in track_sizes.inline.iter_mut().enumerate() {
1921                if self.is_column_collapsed(column_index) {
1922                    mem::take(column_size);
1923                }
1924            }
1925            for (row_index, row_size) in track_sizes.block.iter_mut().enumerate() {
1926                if self.is_row_collapsed(row_index) {
1927                    mem::take(row_size);
1928                }
1929            }
1930            let writing_mode = self.table.style.writing_mode;
1931            if !writing_mode.is_bidi_ltr() {
1932                track_sizes.inline.reverse();
1933                collapsed_borders.inline.reverse();
1934                for border_line in &mut collapsed_borders.block {
1935                    border_line.reverse();
1936                }
1937            }
1938            SpecificLayoutInfo::TableGridWithCollapsedBorders(Box::new(SpecificTableGridInfo {
1939                collapsed_borders: if writing_mode.is_horizontal() {
1940                    PhysicalVec::new(collapsed_borders.inline, collapsed_borders.block)
1941                } else {
1942                    PhysicalVec::new(collapsed_borders.block, collapsed_borders.inline)
1943                },
1944                track_sizes: if writing_mode.is_horizontal() {
1945                    PhysicalVec::new(track_sizes.inline, track_sizes.block)
1946                } else {
1947                    PhysicalVec::new(track_sizes.block, track_sizes.inline)
1948                },
1949            }))
1950        })
1951    }
1952
1953    fn is_row_collapsed(&self, row_index: usize) -> bool {
1954        let Some(row) = &self.table.rows.get(row_index) else {
1955            return false;
1956        };
1957
1958        let row = row.borrow();
1959        if row.base.style.get_inherited_box().visibility == Visibility::Collapse {
1960            return true;
1961        }
1962        let row_group = match row.group_index {
1963            Some(group_index) => self.table.row_groups[group_index].borrow(),
1964            None => return false,
1965        };
1966        row_group.base.style.get_inherited_box().visibility == Visibility::Collapse
1967    }
1968
1969    fn is_column_collapsed(&self, column_index: usize) -> bool {
1970        let Some(column) = &self.table.columns.get(column_index) else {
1971            return false;
1972        };
1973        let column = column.borrow();
1974        if column.base.style.get_inherited_box().visibility == Visibility::Collapse {
1975            return true;
1976        }
1977        let col_group = match column.group_index {
1978            Some(group_index) => self.table.column_groups[group_index].borrow(),
1979            None => return false,
1980        };
1981        col_group.base.style.get_inherited_box().visibility == Visibility::Collapse
1982    }
1983
1984    #[expect(clippy::too_many_arguments)]
1985    fn do_final_cell_layout(
1986        &mut self,
1987        row_index: usize,
1988        column_index: usize,
1989        dimensions: &TableAndTrackDimensions,
1990        baselines: &mut Baselines,
1991        row_fragment_layout: &mut RowFragmentLayout,
1992        row_group_fragment_layout: Option<&mut RowGroupFragmentLayout>,
1993        positioning_context_for_table: &mut PositioningContext,
1994        is_collapsed: bool,
1995    ) {
1996        // The PositioningContext for cells is, in order or preference, the PositioningContext of the row,
1997        // the PositioningContext of the row group, or the PositioningContext of the table.
1998        let row_group_positioning_context =
1999            row_group_fragment_layout.and_then(|layout| layout.positioning_context.as_mut());
2000        let positioning_context = row_fragment_layout
2001            .positioning_context
2002            .as_mut()
2003            .or(row_group_positioning_context)
2004            .unwrap_or(positioning_context_for_table);
2005
2006        let layout = match self.cells_laid_out[row_index][column_index].take() {
2007            Some(layout) => layout,
2008            None => {
2009                return;
2010            },
2011        };
2012        let cell = match self.table.slots[row_index][column_index] {
2013            TableSlot::Cell(ref cell) => cell,
2014            _ => {
2015                warn!("Did not find a non-spanned cell at index with layout.");
2016                return;
2017            },
2018        }
2019        .borrow();
2020
2021        // If this cell has baseline alignment, it can adjust the table's overall baseline.
2022        let row_block_offset = row_fragment_layout.rect.start_corner.block;
2023        let row_baseline = self.row_baselines[row_index];
2024        if cell.content_alignment() == CellContentAlignment::Baseline && !layout.is_empty() {
2025            let baseline = row_block_offset + row_baseline;
2026            if row_index == 0 {
2027                baselines.first = Some(baseline);
2028            }
2029            baselines.last = Some(baseline);
2030        }
2031        let mut row_relative_cell_rect = dimensions.get_cell_rect(
2032            TableSlotCoordinates::new(column_index, row_index),
2033            cell.rowspan,
2034            cell.colspan,
2035        );
2036        row_relative_cell_rect.start_corner -= row_fragment_layout.rect.start_corner;
2037        let mut fragment = cell.create_fragment(
2038            layout,
2039            row_relative_cell_rect,
2040            row_baseline,
2041            positioning_context,
2042            &self.table.style,
2043            &row_fragment_layout.containing_block,
2044            is_collapsed,
2045        );
2046
2047        // Make a table part rectangle relative to the row fragment for the purposes of
2048        // drawing extra backgrounds.
2049        //
2050        // This rectangle is an offset between the row fragment and the other table
2051        // part rectangle (row group, column, column group). Everything between them
2052        // is laid out in a left-to-right fashion, but respecting the verticality of
2053        // the writing mode. This is why below, only the axes are flipped, but the
2054        // rectangle is not flipped for RTL.
2055        let make_relative_to_row_start = |mut rect: LogicalRect<Au>| {
2056            rect.start_corner -= row_fragment_layout.rect.start_corner;
2057            let writing_mode = self.table.style.writing_mode;
2058            PhysicalRect::new(
2059                if writing_mode.is_horizontal() {
2060                    PhysicalPoint::new(rect.start_corner.inline, rect.start_corner.block)
2061                } else {
2062                    PhysicalPoint::new(rect.start_corner.block, rect.start_corner.inline)
2063                },
2064                rect.size.to_physical_size(writing_mode),
2065            )
2066        };
2067
2068        let column = self.table.columns.get(column_index);
2069        let column_group = column
2070            .and_then(|column| column.borrow().group_index)
2071            .and_then(|index| self.table.column_groups.get(index));
2072        if let Some(column_group) = column_group {
2073            let column_group = column_group.borrow();
2074            let rect = make_relative_to_row_start(dimensions.get_column_group_rect(&column_group));
2075            fragment.add_extra_background(ExtraBackground {
2076                style: column_group.shared_background_style.clone(),
2077                rect,
2078            })
2079        }
2080        if let Some(column) = column {
2081            let column = column.borrow();
2082            if !column.is_anonymous {
2083                let rect = make_relative_to_row_start(dimensions.get_column_rect(column_index));
2084                fragment.add_extra_background(ExtraBackground {
2085                    style: column.shared_background_style.clone(),
2086                    rect,
2087                })
2088            }
2089        }
2090        let row = self.table.rows.get(row_index);
2091        let row_group = row
2092            .and_then(|row| row.borrow().group_index)
2093            .and_then(|index| self.table.row_groups.get(index));
2094        if let Some(row_group) = row_group {
2095            let rect =
2096                make_relative_to_row_start(dimensions.get_row_group_rect(&row_group.borrow()));
2097            fragment.add_extra_background(ExtraBackground {
2098                style: row_group.borrow().shared_background_style.clone(),
2099                rect,
2100            })
2101        }
2102        if let Some(row) = row {
2103            let row = row.borrow();
2104            let rect = make_relative_to_row_start(row_fragment_layout.rect);
2105            fragment.add_extra_background(ExtraBackground {
2106                style: row.shared_background_style.clone(),
2107                rect,
2108            })
2109        }
2110
2111        let fragment = Fragment::Box(fragment.into());
2112        cell.context.base.set_fragment(fragment.clone());
2113        row_fragment_layout.fragments.push(fragment);
2114    }
2115
2116    fn make_fragments_for_columns_and_column_groups(
2117        &self,
2118        dimensions: &TableAndTrackDimensions,
2119        fragments: &mut Vec<Fragment>,
2120    ) {
2121        for column_group in self.table.column_groups.iter() {
2122            let column_group = column_group.borrow();
2123            if !column_group.is_empty() {
2124                let fragment = Fragment::Positioning(PositioningFragment::new_empty(
2125                    column_group.base.base_fragment_info,
2126                    dimensions
2127                        .get_column_group_rect(&column_group)
2128                        .as_physical(None),
2129                    column_group.base.style.clone(),
2130                ));
2131                column_group.base.set_fragment(fragment.clone());
2132                fragments.push(fragment);
2133            }
2134        }
2135
2136        for (column_index, column) in self.table.columns.iter().enumerate() {
2137            let column = column.borrow();
2138            let fragment = Fragment::Positioning(PositioningFragment::new_empty(
2139                column.base.base_fragment_info,
2140                dimensions.get_column_rect(column_index).as_physical(None),
2141                column.base.style.clone(),
2142            ));
2143            column.base.set_fragment(fragment.clone());
2144            fragments.push(fragment);
2145        }
2146    }
2147
2148    fn compute_border_collapse(&mut self, writing_mode: WritingMode) {
2149        if self.table.style.get_inherited_table().border_collapse != BorderCollapse::Collapse {
2150            self.collapsed_borders = None;
2151            return;
2152        }
2153
2154        let mut collapsed_borders = LogicalVec2 {
2155            block: vec![
2156                vec![Default::default(); self.table.size.width];
2157                self.table.size.height + 1
2158            ],
2159            inline: vec![
2160                vec![Default::default(); self.table.size.height];
2161                self.table.size.width + 1
2162            ],
2163        };
2164
2165        let apply_border = |collapsed_borders: &mut CollapsedBorders,
2166                            layout_style: &LayoutStyle,
2167                            block: &Range<usize>,
2168                            inline: &Range<usize>| {
2169            let border = CollapsedBorder::from_layout_style(layout_style, writing_mode);
2170            border
2171                .block_start
2172                .max_assign_to_slice(&mut collapsed_borders.block[block.start][inline.clone()]);
2173            border
2174                .block_end
2175                .max_assign_to_slice(&mut collapsed_borders.block[block.end][inline.clone()]);
2176            border
2177                .inline_start
2178                .max_assign_to_slice(&mut collapsed_borders.inline[inline.start][block.clone()]);
2179            border
2180                .inline_end
2181                .max_assign_to_slice(&mut collapsed_borders.inline[inline.end][block.clone()]);
2182        };
2183        let hide_inner_borders = |collapsed_borders: &mut CollapsedBorders,
2184                                  block: &Range<usize>,
2185                                  inline: &Range<usize>| {
2186            for x in inline.clone() {
2187                for y in block.clone() {
2188                    if x != inline.start {
2189                        collapsed_borders.inline[x][y].hide();
2190                    }
2191                    if y != block.start {
2192                        collapsed_borders.block[y][x].hide();
2193                    }
2194                }
2195            }
2196        };
2197        let all_rows = 0..self.table.size.height;
2198        let all_columns = 0..self.table.size.width;
2199        for row_index in all_rows.clone() {
2200            for column_index in all_columns.clone() {
2201                let cell = match self.table.slots[row_index][column_index] {
2202                    TableSlot::Cell(ref cell) => cell,
2203                    _ => continue,
2204                }
2205                .borrow();
2206                let block_range = row_index..row_index + cell.rowspan;
2207                let inline_range = column_index..column_index + cell.colspan;
2208                hide_inner_borders(&mut collapsed_borders, &block_range, &inline_range);
2209                apply_border(
2210                    &mut collapsed_borders,
2211                    &cell.context.layout_style(),
2212                    &block_range,
2213                    &inline_range,
2214                );
2215            }
2216        }
2217        for (row_index, row) in self.table.rows.iter().enumerate() {
2218            let row = row.borrow();
2219            apply_border(
2220                &mut collapsed_borders,
2221                &row.layout_style(),
2222                &(row_index..row_index + 1),
2223                &all_columns,
2224            );
2225        }
2226        for row_group in &self.table.row_groups {
2227            let row_group = row_group.borrow();
2228            apply_border(
2229                &mut collapsed_borders,
2230                &row_group.layout_style(),
2231                &row_group.track_range,
2232                &all_columns,
2233            );
2234        }
2235        for (column_index, column) in self.table.columns.iter().enumerate() {
2236            let column = column.borrow();
2237            apply_border(
2238                &mut collapsed_borders,
2239                &column.layout_style(),
2240                &all_rows,
2241                &(column_index..column_index + 1),
2242            );
2243        }
2244        for column_group in &self.table.column_groups {
2245            let column_group = column_group.borrow();
2246            apply_border(
2247                &mut collapsed_borders,
2248                &column_group.layout_style(),
2249                &all_rows,
2250                &column_group.track_range,
2251            );
2252        }
2253        apply_border(
2254            &mut collapsed_borders,
2255            &self.table.layout_style_for_grid(),
2256            &all_rows,
2257            &all_columns,
2258        );
2259
2260        self.collapsed_borders = Some(collapsed_borders);
2261    }
2262
2263    fn get_collapsed_border_widths_for_area(
2264        &self,
2265        area: LogicalSides<usize>,
2266    ) -> Option<LogicalSides<Au>> {
2267        let collapsed_borders = self.collapsed_borders.as_ref()?;
2268        let columns = || area.inline_start..area.inline_end;
2269        let rows = || area.block_start..area.block_end;
2270        let max_width = |slice: &[CollapsedBorder]| {
2271            let slice_widths = slice.iter().map(|collapsed_border| collapsed_border.width);
2272            slice_widths.max().unwrap_or_default()
2273        };
2274        Some(area.map_inline_and_block_axes(
2275            |column| max_width(&collapsed_borders.inline[*column][rows()]) / 2,
2276            |row| max_width(&collapsed_borders.block[*row][columns()]) / 2,
2277        ))
2278    }
2279}
2280
2281struct RowFragmentLayout<'a> {
2282    row: &'a TableTrack,
2283    rect: LogicalRect<Au>,
2284    containing_block: ContainingBlock<'a>,
2285    positioning_context: Option<PositioningContext>,
2286    fragments: Vec<Fragment>,
2287}
2288
2289impl<'a> RowFragmentLayout<'a> {
2290    fn new(
2291        table_row: &'a TableTrack,
2292        index: usize,
2293        dimensions: &TableAndTrackDimensions,
2294        table_style: &'a ComputedValues,
2295    ) -> Self {
2296        let rect = dimensions.get_row_rect(index);
2297        let containing_block = ContainingBlock {
2298            size: ContainingBlockSize {
2299                inline: rect.size.inline,
2300                block: SizeConstraint::Definite(rect.size.block),
2301            },
2302            style: table_style,
2303        };
2304        Self {
2305            row: table_row,
2306            rect,
2307            positioning_context: PositioningContext::new_for_layout_box_base(&table_row.base),
2308            containing_block,
2309            fragments: Vec::new(),
2310        }
2311    }
2312    fn finish(
2313        mut self,
2314        layout_context: &LayoutContext,
2315        table_positioning_context: &mut PositioningContext,
2316        containing_block_for_logical_conversion: &ContainingBlock,
2317        containing_block_for_children: &ContainingBlock,
2318        row_group_fragment_layout: &mut Option<RowGroupFragmentLayout>,
2319    ) -> Fragment {
2320        if self.row.base.style.get_box().position == Position::Relative {
2321            self.rect.start_corner +=
2322                relative_adjustement(&self.row.base.style, containing_block_for_children);
2323        }
2324
2325        let (inline_size, block_size) = if let Some(row_group_layout) = row_group_fragment_layout {
2326            self.rect.start_corner -= row_group_layout.rect.start_corner;
2327            (
2328                row_group_layout.rect.size.inline,
2329                SizeConstraint::Definite(row_group_layout.rect.size.block),
2330            )
2331        } else {
2332            (
2333                containing_block_for_logical_conversion.size.inline,
2334                containing_block_for_logical_conversion.size.block,
2335            )
2336        };
2337
2338        let row_group_containing_block = ContainingBlock {
2339            size: ContainingBlockSize {
2340                inline: inline_size,
2341                block: block_size,
2342            },
2343            style: containing_block_for_logical_conversion.style,
2344        };
2345
2346        let mut row_fragment = BoxFragment::new(
2347            self.row.base.base_fragment_info,
2348            self.row.base.style.clone(),
2349            self.fragments,
2350            self.rect.as_physical(Some(&row_group_containing_block)),
2351            PhysicalSides::zero(), /* padding */
2352            PhysicalSides::zero(), /* border */
2353            PhysicalSides::zero(), /* margin */
2354            None,                  /* specific_layout_info */
2355        );
2356        row_fragment.set_does_not_paint_background();
2357
2358        if let Some(mut row_positioning_context) = self.positioning_context.take() {
2359            row_positioning_context.layout_collected_children(layout_context, &mut row_fragment);
2360
2361            let parent_positioning_context = row_group_fragment_layout
2362                .as_mut()
2363                .and_then(|layout| layout.positioning_context.as_mut())
2364                .unwrap_or(table_positioning_context);
2365            parent_positioning_context.append(row_positioning_context);
2366        }
2367
2368        let fragment = Fragment::Box(row_fragment.into());
2369        self.row.base.set_fragment(fragment.clone());
2370        fragment
2371    }
2372}
2373
2374struct RowGroupFragmentLayout {
2375    row_group: ArcRefCell<TableTrackGroup>,
2376    rect: LogicalRect<Au>,
2377    positioning_context: Option<PositioningContext>,
2378    index: usize,
2379    fragments: Vec<Fragment>,
2380}
2381
2382impl RowGroupFragmentLayout {
2383    fn new(
2384        row_group: ArcRefCell<TableTrackGroup>,
2385        index: usize,
2386        dimensions: &TableAndTrackDimensions,
2387    ) -> Self {
2388        let (rect, positioning_context) = {
2389            let row_group = row_group.borrow();
2390            (
2391                dimensions.get_row_group_rect(&row_group),
2392                PositioningContext::new_for_layout_box_base(&row_group.base),
2393            )
2394        };
2395        Self {
2396            row_group,
2397            rect,
2398            positioning_context,
2399            index,
2400            fragments: Vec::new(),
2401        }
2402    }
2403
2404    fn finish(
2405        mut self,
2406        layout_context: &LayoutContext,
2407        table_positioning_context: &mut PositioningContext,
2408        containing_block_for_logical_conversion: &ContainingBlock,
2409        containing_block_for_children: &ContainingBlock,
2410    ) -> Fragment {
2411        let row_group = self.row_group.borrow();
2412        if row_group.base.style.get_box().position == Position::Relative {
2413            self.rect.start_corner +=
2414                relative_adjustement(&row_group.base.style, containing_block_for_children);
2415        }
2416
2417        let mut row_group_fragment = BoxFragment::new(
2418            row_group.base.base_fragment_info,
2419            row_group.base.style.clone(),
2420            self.fragments,
2421            self.rect
2422                .as_physical(Some(containing_block_for_logical_conversion)),
2423            PhysicalSides::zero(), /* padding */
2424            PhysicalSides::zero(), /* border */
2425            PhysicalSides::zero(), /* margin */
2426            None,                  /* specific_layout_info */
2427        );
2428        row_group_fragment.set_does_not_paint_background();
2429
2430        if let Some(mut row_positioning_context) = self.positioning_context.take() {
2431            row_positioning_context
2432                .layout_collected_children(layout_context, &mut row_group_fragment);
2433            table_positioning_context.append(row_positioning_context);
2434        }
2435
2436        let fragment = Fragment::Box(row_group_fragment.into());
2437        row_group.base.set_fragment(fragment.clone());
2438        fragment
2439    }
2440}
2441
2442struct TableAndTrackDimensions {
2443    /// The rect of the full table, not counting for borders, padding, and margin.
2444    table_rect: LogicalRect<Au>,
2445    /// The rect of the full table, not counting for borders, padding, and margin
2446    /// and offset by any border spacing and caption.
2447    table_cells_rect: LogicalRect<Au>,
2448    /// The min and max block offsets of each table row.
2449    row_dimensions: Vec<(Au, Au)>,
2450    /// The min and max inline offsets of each table column
2451    column_dimensions: Vec<(Au, Au)>,
2452}
2453
2454impl TableAndTrackDimensions {
2455    fn new(table_layout: &TableLayout) -> Self {
2456        let border_spacing = table_layout.table.border_spacing();
2457
2458        // The sizes used for a dimension when that dimension has no table tracks.
2459        let fallback_inline_size = table_layout.assignable_width;
2460        let fallback_block_size = table_layout.final_table_height;
2461
2462        let mut column_dimensions = Vec::new();
2463        let mut column_offset = Au::zero();
2464        for column_index in 0..table_layout.table.size.width {
2465            if table_layout.is_column_collapsed(column_index) {
2466                column_dimensions.push((column_offset, column_offset));
2467                continue;
2468            }
2469            let start_offset = column_offset + border_spacing.inline;
2470            let end_offset = start_offset + table_layout.distributed_column_widths[column_index];
2471            column_dimensions.push((start_offset, end_offset));
2472            column_offset = end_offset;
2473        }
2474        column_offset += if table_layout.table.size.width == 0 {
2475            fallback_inline_size
2476        } else {
2477            border_spacing.inline
2478        };
2479
2480        let mut row_dimensions = Vec::new();
2481        let mut row_offset = Au::zero();
2482        for row_index in 0..table_layout.table.size.height {
2483            if table_layout.is_row_collapsed(row_index) {
2484                row_dimensions.push((row_offset, row_offset));
2485                continue;
2486            }
2487            let start_offset = row_offset + border_spacing.block;
2488            let end_offset = start_offset + table_layout.row_sizes[row_index];
2489            row_dimensions.push((start_offset, end_offset));
2490            row_offset = end_offset;
2491        }
2492        row_offset += if table_layout.table.size.height == 0 {
2493            fallback_block_size
2494        } else {
2495            border_spacing.block
2496        };
2497
2498        let table_start_corner = LogicalVec2 {
2499            inline: column_dimensions.first().map_or_else(Au::zero, |v| v.0),
2500            block: row_dimensions.first().map_or_else(Au::zero, |v| v.0),
2501        };
2502        let table_size = LogicalVec2 {
2503            inline: column_dimensions
2504                .last()
2505                .map_or(fallback_inline_size, |v| v.1),
2506            block: row_dimensions.last().map_or(fallback_block_size, |v| v.1),
2507        } - table_start_corner;
2508        let table_cells_rect = LogicalRect {
2509            start_corner: table_start_corner,
2510            size: table_size,
2511        };
2512
2513        let table_rect = LogicalRect {
2514            start_corner: LogicalVec2::zero(),
2515            size: LogicalVec2 {
2516                inline: column_offset,
2517                block: row_offset,
2518            },
2519        };
2520
2521        Self {
2522            table_rect,
2523            table_cells_rect,
2524            row_dimensions,
2525            column_dimensions,
2526        }
2527    }
2528
2529    fn get_row_rect(&self, row_index: usize) -> LogicalRect<Au> {
2530        let mut row_rect = self.table_cells_rect;
2531        let row_dimensions = self.row_dimensions[row_index];
2532        row_rect.start_corner.block = row_dimensions.0;
2533        row_rect.size.block = row_dimensions.1 - row_dimensions.0;
2534        row_rect
2535    }
2536
2537    fn get_column_rect(&self, column_index: usize) -> LogicalRect<Au> {
2538        let mut row_rect = self.table_cells_rect;
2539        let column_dimensions = self.column_dimensions[column_index];
2540        row_rect.start_corner.inline = column_dimensions.0;
2541        row_rect.size.inline = column_dimensions.1 - column_dimensions.0;
2542        row_rect
2543    }
2544
2545    fn get_row_group_rect(&self, row_group: &TableTrackGroup) -> LogicalRect<Au> {
2546        if row_group.is_empty() {
2547            return LogicalRect::zero();
2548        }
2549
2550        let mut row_group_rect = self.table_cells_rect;
2551        let block_start = self.row_dimensions[row_group.track_range.start].0;
2552        let block_end = self.row_dimensions[row_group.track_range.end - 1].1;
2553        row_group_rect.start_corner.block = block_start;
2554        row_group_rect.size.block = block_end - block_start;
2555        row_group_rect
2556    }
2557
2558    fn get_column_group_rect(&self, column_group: &TableTrackGroup) -> LogicalRect<Au> {
2559        if column_group.is_empty() {
2560            return LogicalRect::zero();
2561        }
2562
2563        let mut column_group_rect = self.table_cells_rect;
2564        let inline_start = self.column_dimensions[column_group.track_range.start].0;
2565        let inline_end = self.column_dimensions[column_group.track_range.end - 1].1;
2566        column_group_rect.start_corner.inline = inline_start;
2567        column_group_rect.size.inline = inline_end - inline_start;
2568        column_group_rect
2569    }
2570
2571    fn get_cell_rect(
2572        &self,
2573        coordinates: TableSlotCoordinates,
2574        rowspan: usize,
2575        colspan: usize,
2576    ) -> LogicalRect<Au> {
2577        let start_corner = LogicalVec2 {
2578            inline: self.column_dimensions[coordinates.x].0,
2579            block: self.row_dimensions[coordinates.y].0,
2580        };
2581        let size = LogicalVec2 {
2582            inline: self.column_dimensions[coordinates.x + colspan - 1].1,
2583            block: self.row_dimensions[coordinates.y + rowspan - 1].1,
2584        } - start_corner;
2585        LogicalRect { start_corner, size }
2586    }
2587}
2588
2589impl Table {
2590    fn border_spacing(&self) -> LogicalVec2<Au> {
2591        if self.style.get_border_collapse() == &BorderCollapse::Collapse {
2592            LogicalVec2::zero()
2593        } else {
2594            let border_spacing = self.style.get_border_spacing();
2595            LogicalVec2 {
2596                inline: border_spacing.horizontal(),
2597                block: border_spacing.vertical(),
2598            }
2599        }
2600    }
2601
2602    fn total_border_spacing(&self) -> LogicalVec2<Au> {
2603        let border_spacing = self.border_spacing();
2604        LogicalVec2 {
2605            inline: if self.size.width > 0 {
2606                border_spacing.inline * (self.size.width as i32 + 1)
2607            } else {
2608                Au::zero()
2609            },
2610            block: if self.size.height > 0 {
2611                border_spacing.block * (self.size.height as i32 + 1)
2612            } else {
2613                Au::zero()
2614            },
2615        }
2616    }
2617
2618    fn get_column_measure_for_column_at_index(
2619        &self,
2620        writing_mode: WritingMode,
2621        column_index: usize,
2622        is_in_fixed_mode: bool,
2623    ) -> CellOrTrackMeasure {
2624        let column = match self.columns.get(column_index) {
2625            Some(column) => column,
2626            None => return CellOrTrackMeasure::zero(),
2627        }
2628        .borrow();
2629
2630        let CellOrColumnOuterSizes {
2631            preferred: preferred_size,
2632            min: min_size,
2633            max: max_size,
2634            percentage: percentage_size,
2635        } = CellOrColumnOuterSizes::new(
2636            &column.base.style,
2637            writing_mode,
2638            &Default::default(),
2639            is_in_fixed_mode,
2640        );
2641
2642        CellOrTrackMeasure {
2643            content_sizes: ContentSizes {
2644                // > The outer min-content width of a table-column or table-column-group is
2645                // > max(min-width, width).
2646                // But that's clearly wrong, since it would be equal to or greater than
2647                // the outer max-content width. So we match other browsers instead.
2648                min_content: min_size.inline,
2649                // > The outer max-content width of a table-column or table-column-group is
2650                // > max(min-width, min(max-width, width)).
2651                // This matches Gecko, but Blink and WebKit ignore max_size.
2652                max_content: preferred_size
2653                    .inline
2654                    .clamp_between_extremums(min_size.inline, max_size.inline),
2655            },
2656            percentage: percentage_size.inline,
2657        }
2658    }
2659
2660    fn get_row_measure_for_row_at_index(
2661        &self,
2662        writing_mode: WritingMode,
2663        row_index: usize,
2664    ) -> CellOrTrackMeasure {
2665        let row = match self.rows.get(row_index) {
2666            Some(row) => row,
2667            None => return CellOrTrackMeasure::zero(),
2668        };
2669
2670        // In the block axis, the min-content and max-content sizes are the same
2671        // (except for new layout boxes like grid and flex containers). Note that
2672        // other browsers don't seem to use the min and max sizing properties here.
2673        let row = row.borrow();
2674        let size = row.base.style.box_size(writing_mode);
2675        let max_size = row.base.style.max_box_size(writing_mode);
2676        let percentage_contribution = get_size_percentage_contribution(&size, &max_size);
2677
2678        CellOrTrackMeasure {
2679            content_sizes: size
2680                .block
2681                .to_numeric()
2682                .and_then(|size| size.to_length())
2683                .map_or_else(Au::zero, Au::from)
2684                .into(),
2685            percentage: percentage_contribution.block,
2686        }
2687    }
2688
2689    pub(crate) fn layout(
2690        &self,
2691        layout_context: &LayoutContext,
2692        positioning_context: &mut PositioningContext,
2693        containing_block_for_children: &ContainingBlock,
2694        containing_block_for_table: &ContainingBlock,
2695    ) -> IndependentFormattingContextLayoutResult {
2696        TableLayout::new(self).layout(
2697            layout_context,
2698            positioning_context,
2699            containing_block_for_children,
2700            containing_block_for_table,
2701        )
2702    }
2703
2704    pub(crate) fn attached_to_tree(&self, layout_box: WeakLayoutBox) {
2705        for caption in &self.captions {
2706            caption
2707                .borrow_mut()
2708                .context
2709                .base
2710                .parent_box
2711                .replace(layout_box.clone());
2712        }
2713        for row_group in &self.row_groups {
2714            row_group
2715                .borrow_mut()
2716                .base
2717                .parent_box
2718                .replace(layout_box.clone());
2719        }
2720        for column_group in &self.column_groups {
2721            column_group
2722                .borrow_mut()
2723                .base
2724                .parent_box
2725                .replace(layout_box.clone());
2726        }
2727        for row in &self.rows {
2728            let row = &mut *row.borrow_mut();
2729            if let Some(group_index) = row.group_index {
2730                row.base.parent_box.replace(WeakLayoutBox::TableLevelBox(
2731                    WeakTableLevelBox::TrackGroup(self.row_groups[group_index].downgrade()),
2732                ));
2733            } else {
2734                row.base.parent_box.replace(layout_box.clone());
2735            }
2736        }
2737        for column in &self.columns {
2738            let column = &mut *column.borrow_mut();
2739            if let Some(group_index) = column.group_index {
2740                column.base.parent_box.replace(WeakLayoutBox::TableLevelBox(
2741                    WeakTableLevelBox::TrackGroup(self.column_groups[group_index].downgrade()),
2742                ));
2743            } else {
2744                column.base.parent_box.replace(layout_box.clone());
2745            }
2746        }
2747        for row_index in 0..self.size.height {
2748            let row = WeakLayoutBox::TableLevelBox(WeakTableLevelBox::Track(
2749                self.rows[row_index].downgrade(),
2750            ));
2751            for column_index in 0..self.size.width {
2752                if let TableSlot::Cell(ref cell) = self.slots[row_index][column_index] {
2753                    cell.borrow_mut()
2754                        .context
2755                        .base
2756                        .parent_box
2757                        .replace(row.clone());
2758                }
2759            }
2760        }
2761    }
2762}
2763
2764impl ComputeInlineContentSizes for Table {
2765    #[servo_tracing::instrument(name = "Table::compute_inline_content_sizes", skip_all)]
2766    fn compute_inline_content_sizes(
2767        &self,
2768        layout_context: &LayoutContext,
2769        constraint_space: &ConstraintSpace,
2770    ) -> InlineContentSizesResult {
2771        let writing_mode = constraint_space.style.writing_mode;
2772        let mut layout = TableLayout::new(self);
2773        layout.compute_border_collapse(writing_mode);
2774        layout.pbm = self
2775            .layout_style(Some(&layout))
2776            .padding_border_margin_with_writing_mode_and_containing_block_inline_size(
2777                writing_mode,
2778                Au::zero(),
2779            );
2780        layout.compute_measures(layout_context, writing_mode);
2781
2782        let grid_content_sizes = layout.compute_grid_min_max();
2783
2784        // Padding and border should apply to the table grid, but they will be taken into
2785        // account when computing the inline content sizes of the table wrapper (our parent), so
2786        // this code removes their contribution from the inline content size of the caption.
2787        let caption_content_sizes = ContentSizes::from(
2788            layout.compute_caption_minimum_inline_size(layout_context) -
2789                layout.pbm.padding_border_sums.inline,
2790        );
2791
2792        InlineContentSizesResult {
2793            sizes: grid_content_sizes.max(caption_content_sizes),
2794            depends_on_block_constraints: false,
2795        }
2796    }
2797}
2798
2799impl Table {
2800    #[inline]
2801    pub(crate) fn layout_style<'a>(
2802        &'a self,
2803        layout: Option<&'a TableLayout<'a>>,
2804    ) -> LayoutStyle<'a> {
2805        LayoutStyle::Table(TableLayoutStyle {
2806            table: self,
2807            layout,
2808        })
2809    }
2810
2811    #[inline]
2812    pub(crate) fn layout_style_for_grid(&self) -> LayoutStyle<'_> {
2813        LayoutStyle::Default(&self.grid_style)
2814    }
2815}
2816
2817impl TableTrack {
2818    #[inline]
2819    pub(crate) fn layout_style(&self) -> LayoutStyle<'_> {
2820        LayoutStyle::Default(&self.base.style)
2821    }
2822}
2823
2824impl TableTrackGroup {
2825    #[inline]
2826    pub(crate) fn layout_style(&self) -> LayoutStyle<'_> {
2827        LayoutStyle::Default(&self.base.style)
2828    }
2829}
2830
2831impl TableLayoutStyle<'_> {
2832    #[inline]
2833    pub(crate) fn style(&self) -> &ComputedValues {
2834        &self.table.style
2835    }
2836
2837    #[inline]
2838    pub(crate) fn collapses_borders(&self) -> bool {
2839        self.style().get_inherited_table().border_collapse == BorderCollapse::Collapse
2840    }
2841
2842    pub(crate) fn halved_collapsed_border_widths(&self) -> LogicalSides<Au> {
2843        debug_assert!(self.collapses_borders());
2844        let area = LogicalSides {
2845            inline_start: 0,
2846            inline_end: self.table.size.width,
2847            block_start: 0,
2848            block_end: self.table.size.height,
2849        };
2850        if let Some(layout) = self.layout {
2851            layout.get_collapsed_border_widths_for_area(area)
2852        } else {
2853            // TODO: this should be cached.
2854            let mut layout = TableLayout::new(self.table);
2855            layout.compute_border_collapse(self.style().writing_mode);
2856            layout.get_collapsed_border_widths_for_area(area)
2857        }
2858        .expect("Collapsed borders should be computed")
2859    }
2860}
2861
2862impl TableSlotCell {
2863    fn content_alignment(&self) -> CellContentAlignment {
2864        // The spec still assumes that `vertical-align` is a longhand, so it's not very clear
2865        // if this logic is completely correct, but it seems to match Firefox.
2866        // <https://github.com/w3c/csswg-drafts/issues/13458>
2867        let style_box = self.context.base.style.get_box();
2868        match style_box.baseline_shift {
2869            BaselineShift::Keyword(BaselineShiftKeyword::Top) => CellContentAlignment::Top,
2870            BaselineShift::Keyword(BaselineShiftKeyword::Bottom) => CellContentAlignment::Bottom,
2871            _ => match style_box.alignment_baseline {
2872                AlignmentBaseline::Middle => CellContentAlignment::Middle,
2873                _ => CellContentAlignment::Baseline,
2874            },
2875        }
2876    }
2877
2878    #[expect(clippy::too_many_arguments)]
2879    fn create_fragment(
2880        &self,
2881        mut layout: CellLayout,
2882        cell_rect: LogicalRect<Au>,
2883        cell_baseline: Au,
2884        positioning_context: &mut PositioningContext,
2885        table_style: &ComputedValues,
2886        containing_block: &ContainingBlock,
2887        is_collapsed: bool,
2888    ) -> BoxFragment {
2889        // This must be scoped to this function because it conflicts with euclid's Zero.
2890        use style::Zero as StyleZero;
2891
2892        let cell_content_rect = cell_rect.deflate(&(layout.padding + layout.border));
2893        let content_block_size = layout.layout.content_block_size;
2894        let free_space = || Au::zero().max(cell_content_rect.size.block - content_block_size);
2895        let vertical_align_offset = match self.content_alignment() {
2896            CellContentAlignment::Top => Au::zero(),
2897            CellContentAlignment::Bottom => free_space(),
2898            CellContentAlignment::Middle => free_space().scale_by(0.5),
2899            CellContentAlignment::Baseline => {
2900                cell_baseline -
2901                    (layout.padding.block_start + layout.border.block_start) -
2902                    layout.ascent()
2903            },
2904        };
2905
2906        let mut base_fragment_info = self.context.base.base_fragment_info;
2907        if self.context.base.style.get_inherited_table().empty_cells == EmptyCells::Hide &&
2908            table_style.get_inherited_table().border_collapse != BorderCollapse::Collapse &&
2909            layout.is_empty_for_empty_cells()
2910        {
2911            base_fragment_info.flags.insert(FragmentFlags::DO_NOT_PAINT);
2912        }
2913
2914        if is_collapsed {
2915            base_fragment_info.flags.insert(FragmentFlags::IS_COLLAPSED);
2916        }
2917
2918        // Create an `AnonymousFragment` to move the cell contents to the cell baseline.
2919        let mut vertical_align_fragment_rect = cell_content_rect;
2920        vertical_align_fragment_rect.start_corner = LogicalVec2 {
2921            inline: Au::zero(),
2922            block: vertical_align_offset,
2923        };
2924        let vertical_align_fragment = PositioningFragment::new_anonymous(
2925            self.context.base.style.clone(),
2926            vertical_align_fragment_rect.as_physical(None),
2927            layout.layout.fragments,
2928            false, /* is_line_box */
2929        );
2930
2931        // Adjust the static position of all absolute children based on the
2932        // final content rect of this fragment. Note that we are not shifting by the position of the
2933        // Anonymous fragment we use to shift content to the baseline.
2934        //
2935        // TODO(mrobinson): This is correct for absolutes that are direct children of the table
2936        // cell, but wrong for absolute fragments that are more deeply nested in the hierarchy of
2937        // fragments.
2938        let physical_cell_rect = cell_content_rect.as_physical(Some(containing_block));
2939        layout
2940            .positioning_context
2941            .adjust_static_position_of_hoisted_fragments_with_offset(
2942                &physical_cell_rect.origin.to_vector(),
2943                PositioningContextLength::zero(),
2944            );
2945        positioning_context.append(layout.positioning_context);
2946
2947        let specific_layout_info = (table_style.get_inherited_table().border_collapse ==
2948            BorderCollapse::Collapse)
2949            .then_some(SpecificLayoutInfo::TableCellWithCollapsedBorders);
2950
2951        BoxFragment::new(
2952            base_fragment_info,
2953            self.context.base.style.clone(),
2954            vec![Fragment::Positioning(vertical_align_fragment)],
2955            physical_cell_rect,
2956            layout.padding.to_physical(table_style.writing_mode),
2957            layout.border.to_physical(table_style.writing_mode),
2958            PhysicalSides::zero(), /* margin */
2959            specific_layout_info,
2960        )
2961        .with_baselines(layout.layout.baselines)
2962    }
2963}
2964
2965fn get_size_percentage_contribution(
2966    size: &LogicalVec2<Size<ComputedLengthPercentage>>,
2967    max_size: &LogicalVec2<Size<ComputedLengthPercentage>>,
2968) -> LogicalVec2<Option<Percentage>> {
2969    // From <https://drafts.csswg.org/css-tables/#percentage-contribution>
2970    // > The percentage contribution of a table cell, column, or column group is defined
2971    // > in terms of the computed values of width and max-width that have computed values
2972    // > that are percentages:
2973    // >    min(percentage width, percentage max-width).
2974    // > If the computed values are not percentages, then 0% is used for width, and an
2975    // > infinite percentage is used for max-width.
2976    LogicalVec2 {
2977        inline: max_two_optional_percentages(
2978            size.inline.to_percentage(),
2979            max_size.inline.to_percentage(),
2980        ),
2981        block: max_two_optional_percentages(
2982            size.block.to_percentage(),
2983            max_size.block.to_percentage(),
2984        ),
2985    }
2986}
2987
2988struct CellOrColumnOuterSizes {
2989    min: LogicalVec2<Au>,
2990    preferred: LogicalVec2<Au>,
2991    max: LogicalVec2<Option<Au>>,
2992    percentage: LogicalVec2<Option<Percentage>>,
2993}
2994
2995impl CellOrColumnOuterSizes {
2996    fn new(
2997        style: &Arc<ComputedValues>,
2998        writing_mode: WritingMode,
2999        padding_border_sums: &LogicalVec2<Au>,
3000        is_in_fixed_mode: bool,
3001    ) -> Self {
3002        let box_sizing = style.get_position().box_sizing;
3003        let outer_size = |size: LogicalVec2<Au>| match box_sizing {
3004            BoxSizing::ContentBox => size + *padding_border_sums,
3005            BoxSizing::BorderBox => LogicalVec2 {
3006                inline: size.inline.max(padding_border_sums.inline),
3007                block: size.block.max(padding_border_sums.block),
3008            },
3009        };
3010
3011        let outer_option_size = |size: LogicalVec2<Option<Au>>| match box_sizing {
3012            BoxSizing::ContentBox => size.map_inline_and_block_axes(
3013                |inline| inline.map(|inline| inline + padding_border_sums.inline),
3014                |block| block.map(|block| block + padding_border_sums.block),
3015            ),
3016            BoxSizing::BorderBox => size.map_inline_and_block_axes(
3017                |inline| inline.map(|inline| inline.max(padding_border_sums.inline)),
3018                |block| block.map(|block| block.max(padding_border_sums.block)),
3019            ),
3020        };
3021
3022        let get_size_for_axis = |size: &Size<ComputedLengthPercentage>| {
3023            // Note that measures treat all size values other than <length>
3024            // as the initial value of the property.
3025            size.to_numeric()
3026                .and_then(|length_percentage| length_percentage.to_length())
3027                .map(Au::from)
3028        };
3029
3030        let size = style.box_size(writing_mode);
3031        if is_in_fixed_mode {
3032            return Self {
3033                percentage: size.map(|v| v.to_percentage()),
3034                preferred: outer_option_size(size.map(get_size_for_axis))
3035                    .map(|v| v.unwrap_or_default()),
3036                min: LogicalVec2::default(),
3037                max: LogicalVec2::default(),
3038            };
3039        }
3040
3041        let min_size = style.min_box_size(writing_mode);
3042        let max_size = style.max_box_size(writing_mode);
3043
3044        Self {
3045            min: outer_size(min_size.map(|v| get_size_for_axis(v).unwrap_or_default())),
3046            preferred: outer_size(size.map(|v| get_size_for_axis(v).unwrap_or_default())),
3047            max: outer_option_size(max_size.map(get_size_for_axis)),
3048            percentage: get_size_percentage_contribution(&size, &max_size),
3049        }
3050    }
3051}
3052
3053struct RowspanToDistribute<'a> {
3054    coordinates: TableSlotCoordinates,
3055    cell: AtomicRef<'a, TableSlotCell>,
3056    measure: &'a CellOrTrackMeasure,
3057}
3058
3059impl RowspanToDistribute<'_> {
3060    fn range(&self) -> Range<usize> {
3061        self.coordinates.y..self.coordinates.y + self.cell.rowspan
3062    }
3063
3064    /// Returns true if other is a proper subset of [`self`].
3065    fn fully_encloses(&self, other: &RowspanToDistribute) -> bool {
3066        self.range() != other.range() &&
3067            other.coordinates.y >= self.coordinates.y &&
3068            other.range().end <= self.range().end
3069    }
3070}
3071
3072/// The inline size constraints provided by a cell that span multiple columns (`colspan` > 1).
3073/// These constraints are distributed to the individual columns that make up this cell's span.
3074#[derive(Debug)]
3075struct ColspanToDistribute {
3076    starting_column: usize,
3077    span: usize,
3078    content_sizes: ContentSizes,
3079    percentage: Option<Percentage>,
3080}
3081
3082impl ColspanToDistribute {
3083    /// A comparison function to sort the colspan cell constraints primarily by their span
3084    /// width and secondarily by their starting column. This is not an implementation of
3085    /// `PartialOrd` because we want to return [`Ordering::Equal`] even if `self != other`.
3086    fn comparison_for_sort(a: &Self, b: &Self) -> Ordering {
3087        a.span
3088            .cmp(&b.span)
3089            .then_with(|| a.starting_column.cmp(&b.starting_column))
3090    }
3091
3092    fn range(&self) -> Range<usize> {
3093        self.starting_column..self.starting_column + self.span
3094    }
3095}
3096
3097#[cfg(test)]
3098mod test {
3099    use app_units::MIN_AU;
3100
3101    use super::*;
3102    use crate::sizing::ContentSizes;
3103
3104    #[test]
3105    fn test_colspan_to_distribute_first_sort_by_span() {
3106        let a = ColspanToDistribute {
3107            starting_column: 0,
3108            span: 0,
3109            content_sizes: ContentSizes {
3110                min_content: MIN_AU,
3111                max_content: MIN_AU,
3112            },
3113            percentage: None,
3114        };
3115
3116        let b = ColspanToDistribute {
3117            starting_column: 0,
3118            span: 1,
3119            content_sizes: ContentSizes {
3120                min_content: MIN_AU,
3121                max_content: MIN_AU,
3122            },
3123            percentage: None,
3124        };
3125
3126        let ordering = ColspanToDistribute::comparison_for_sort(&a, &b);
3127        assert_eq!(ordering, Ordering::Less);
3128    }
3129
3130    #[test]
3131    fn test_colspan_to_distribute_if_spans_are_equal_sort_by_starting_column() {
3132        let a = ColspanToDistribute {
3133            starting_column: 0,
3134            span: 0,
3135            content_sizes: ContentSizes {
3136                min_content: MIN_AU,
3137                max_content: MIN_AU,
3138            },
3139            percentage: None,
3140        };
3141
3142        let b = ColspanToDistribute {
3143            starting_column: 1,
3144            span: 0,
3145            content_sizes: ContentSizes {
3146                min_content: MIN_AU,
3147                max_content: MIN_AU,
3148            },
3149            percentage: None,
3150        };
3151
3152        let ordering = ColspanToDistribute::comparison_for_sort(&a, &b);
3153        assert_eq!(ordering, Ordering::Less);
3154    }
3155}