Mirrors/servo
1
0
Fork 0
mirror of https://github.com/servo/servo.git synced 2025-08-03 04:30:10 +01:00
Code Issues Projects Releases Packages Wiki Activity

layout: Implement computation of table column widths (#31165)

Browse source 
* layout: Implement computation of table column widths

This change implements the various steps of table column width
computation, ignoring features that don't exist yet (such as separated
borders, column elements, and colgroups).

Co-authored-by: Oriol Brufau <obrufau@igalia.com>

* Fix an issue with the assignment of column percent width

* Respond to review comments

---------

Co-authored-by: Oriol Brufau <obrufau@igalia.com>
This commit is contained in:
Martin Robinson 2024-01-26 00:13:13 +01:00 • committed by GitHub
parent dc34eec4d4
commit d68c7e7881
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
16 changed files with 707 additions and 121 deletions
Download patch file Download diff file Expand all files Collapse all files

745
components/layout_2020/table/layout.rs
View file

@ -2,11 +2,11 @@
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at https://mozilla.org/MPL/2.0/. */
use app_units::Au;
use app_units::{Au, MAX_AU};
use euclid::num::Zero;
use log::warn;
use style::logical_geometry::WritingMode;
use style::values::computed::{CSSPixelLength, Length, LengthOrAuto};
use style::values::computed::{CSSPixelLength, Length, LengthOrAuto, Percentage};
use style::values::generics::length::GenericLengthPercentageOrAuto::{Auto, LengthPercentage};
use super::{Table, TableSlot, TableSlotCell};
@ -16,7 +16,7 @@ use crate::fragment_tree::{BoxFragment, CollapsedBlockMargins, Fragment};
use crate::geom::{LogicalRect, LogicalSides, LogicalVec2};
use crate::positioned::{PositioningContext, PositioningContextLength};
use crate::sizing::ContentSizes;
use crate::style_ext::{ComputedValuesExt, PaddingBorderMargin};
use crate::style_ext::{Clamp, ComputedValuesExt, PaddingBorderMargin};
use crate::table::TableSlotCoordinates;
use crate::ContainingBlock;
@ -37,19 +37,42 @@ struct CellLayout {
struct TableLayout<'a> {
table: &'a Table,
pbm: PaddingBorderMargin,
column_constrainedness: Vec<bool>,
column_has_originating_cell: Vec<bool>,
cell_measures: Vec<Vec<CellOrColumnMeasure>>,
assignable_width: Au,
column_sizes: Vec<Au>,
column_measures: Vec<CellOrColumnMeasure>,
distributed_column_widths: Vec<Au>,
row_sizes: Vec<Au>,
cells_laid_out: Vec<Vec<Option<CellLayout>>>,
}
#[derive(Clone, Debug)]
struct CellOrColumnMeasure {
content_sizes: ContentSizes,
percentage_width: Percentage,
}
impl CellOrColumnMeasure {
fn zero() -> Self {
Self {
content_sizes: ContentSizes::zero(),
percentage_width: Percentage(0.),
}
}
}
impl<'a> TableLayout<'a> {
fn new(table: &'a Table) -> TableLayout {
Self {
table,
pbm: PaddingBorderMargin::zero(),
column_constrainedness: Vec::new(),
column_has_originating_cell: Vec::new(),
cell_measures: Vec::new(),
assignable_width: Au::zero(),
column_sizes: Vec::new(),
column_measures: Vec::new(),
distributed_column_widths: Vec::new(),
row_sizes: Vec::new(),
cells_laid_out: Vec::new(),
}
@ -63,24 +86,468 @@ impl<'a> TableLayout<'a> {
positioning_context: &mut PositioningContext,
containing_block: &ContainingBlock,
) {
let (inline_content_sizes, column_content_sizes) = self
.table
.compute_inline_content_sizes(layout_context, containing_block.style.writing_mode);
self.calculate_assignable_table_width(containing_block, inline_content_sizes);
self.column_sizes =
self.distribute_width_to_columns(column_content_sizes, containing_block);
let writing_mode = containing_block.style.writing_mode;
self.compute_column_constrainedness_and_has_originating_cells(writing_mode);
self.compute_cell_measures(layout_context, containing_block);
self.compute_column_measures();
self.compute_table_width(containing_block);
self.distributed_column_widths = self.distribute_width_to_columns();
self.do_row_layout_first_pass(layout_context, containing_block, positioning_context);
self.distribute_height_to_rows();
}
fn calculate_assignable_table_width(
/// This is an implementation of *Computing Cell Measures* from
/// <https://drafts.csswg.org/css-tables/#computing-cell-measures>.
pub(crate) fn compute_cell_measures(
&mut self,
layout_context: &LayoutContext,
containing_block: &ContainingBlock,
inline_content_sizes: ContentSizes,
) {
let grid_min_inline_size = inline_content_sizes.min_content;
let grid_max_inline_size = inline_content_sizes.max_content;
let writing_mode = containing_block.style.writing_mode;
for row_index in 0..self.table.size.height {
let mut row_measures = vec![CellOrColumnMeasure::zero(); self.table.size.width];
for column_index in 0..self.table.size.width {
let cell = match self.table.slots[row_index][column_index] {
TableSlot::Cell(ref cell) => cell,
_ => continue,
};
// TODO: Should `box_size` percentages be treated as zero here or resolved against
// the containing block?
let pbm = cell.style.padding_border_margin(containing_block);
let min_inline_size: Au = cell
.style
.min_box_size(writing_mode)
.inline
.percentage_relative_to(Length::zero())
.map(|value| value.into())
.auto_is(Au::zero);
let max_inline_size: Au = cell.style.max_box_size(writing_mode).inline.map_or_else(
|| MAX_AU,
|length_percentage| length_percentage.resolve(Length::zero()).into(),
);
let inline_size: Au = cell
.style
.box_size(writing_mode)
.inline
.percentage_relative_to(Length::zero())
.map(|value| value.into())
.auto_is(Au::zero);
let content_sizes = cell
.contents
.contents
.inline_content_sizes(layout_context, writing_mode);
// > The outer min-content width of a table-cell is max(min-width, min-content width)
// > adjusted by the cell intrinsic offsets.
let mut outer_min_content_width = content_sizes.min_content.max(min_inline_size);
let mut outer_max_content_width = if !self.column_constrainedness[column_index] {
// > The outer max-content width of a table-cell in a non-constrained column is
// > max(min-width, width, min-content width, min(max-width, max-content width))
// > adjusted by the cell intrinsic offsets.
min_inline_size
.max(inline_size)
.max(content_sizes.min_content)
.max(max_inline_size.min(content_sizes.max_content))
} else {
// > The outer max-content width of a table-cell in a constrained column is
// > max(min-width, width, min-content width, min(max-width, width)) adjusted by the
// > cell intrinsic offsets.
min_inline_size
.max(inline_size)
.max(content_sizes.min_content)
.max(max_inline_size.min(inline_size))
};
// > The percentage contribution of a table cell, column, or column group is defined
// > in terms of the computed values of width and max-width that have computed values
// > that are percentages:
// > min(percentage width, percentage max-width).
// > If the computed values are not percentages, then 0% is used for width, and an
// > infinite percentage is used for max-width.
let inline_size_percent = cell
.style
.box_size(writing_mode)
.inline
.non_auto()
.and_then(|length_percentage| length_percentage.to_percentage())
.unwrap_or_else(|| Percentage(0.));
let max_inline_size_percent = cell
.style
.max_box_size(writing_mode)
.inline
.and_then(|length_percentage| length_percentage.to_percentage())
.unwrap_or_else(|| Percentage(f32::INFINITY));
let percentage_contribution =
Percentage(inline_size_percent.0.min(max_inline_size_percent.0));
outer_min_content_width += pbm.padding_border_sums.inline.into();
outer_max_content_width += pbm.padding_border_sums.inline.into();
row_measures[column_index] = CellOrColumnMeasure {
content_sizes: ContentSizes {
min_content: outer_min_content_width,
max_content: outer_max_content_width,
},
percentage_width: percentage_contribution,
};
}
self.cell_measures.push(row_measures);
}
}
/// Compute the constrainedness of every column in the table.
///
/// > A column is constrained if its corresponding table-column-group (if any), its
/// > corresponding table-column (if any), or any of the cells spanning only that
/// > column has a computed width that is not "auto", and is not a percentage.
fn compute_column_constrainedness_and_has_originating_cells(
&mut self,
writing_mode: WritingMode,
) {
for column_index in 0..self.table.size.width {
let mut column_constrained = false;
let mut column_has_originating_cell = false;
for row_index in 0..self.table.size.height {
let coords = TableSlotCoordinates::new(column_index, row_index);
let cell_constrained = match self.table.resolve_first_cell(coords) {
Some(cell) if cell.colspan == 1 => cell
.style
.box_size(writing_mode)
.inline
.non_auto()
.map(|length_percentage| length_percentage.to_length().is_some())
.unwrap_or(false),
_ => false,
};
column_has_originating_cell = column_has_originating_cell ||
matches!(self.table.get_slot(coords), Some(TableSlot::Cell(_)));
column_constrained = column_constrained || cell_constrained;
}
self.column_constrainedness.push(column_constrained);
self.column_has_originating_cell
.push(column_has_originating_cell);
}
}
/// This is an implementation of *Computing Column Measures* from
/// <https://drafts.csswg.org/css-tables/#computing-column-measures>.
fn compute_column_measures(&mut self) {
let mut column_measures = Vec::new();
// Compute the column measures only taking into account cells with colspan == 1.
// This is the base case that will be used to iteratively account for cells with
// larger colspans afterward.
//
// > min-content width of a column based on cells of span up to 1
// > The largest of:
// > - the width specified for the column:
// > - the outer min-content width of its corresponding table-column,
// > if any (and not auto)
// > - the outer min-content width of its corresponding table-column-group, if any
// > - or 0, if there is none
// > - the outer min-content width of each cell that spans the column whose colSpan
// > is 1 (or just the one in the first row in fixed mode) or 0 if there is none
// >
// > max-content width of a column based on cells of span up to 1
// > The largest of:
// > - the outer max-content width of its corresponding
// > table-column-group, if any
// > - the outer max-content width of its corresponding table-column, if any
// > - the outer max-content width of each cell that spans the column
// > whose colSpan is 1 (or just the one in the first row if in fixed mode) or 0
// > if there is no such cell
// >
// > intrinsic percentage width of a column based on cells of span up to 1
// > The largest of the percentage contributions of each cell that spans the column whose colSpan is
// > 1, of its corresponding table-column (if any), and of its corresponding table-column-group (if
// > any)
//
// TODO: Take into account `table-column` and `table-column-group` lengths.
// TODO: Take into account changes to this computation for fixed table layout.
let mut next_span_n = usize::MAX;
for column_index in 0..self.table.size.width {
let mut column_measure = CellOrColumnMeasure::zero();
for row_index in 0..self.table.size.height {
let coords = TableSlotCoordinates::new(column_index, row_index);
match self.table.resolve_first_cell(coords) {
Some(cell) if cell.colspan == 1 => cell,
Some(cell) => {
next_span_n = next_span_n.min(cell.colspan);
continue;
},
_ => continue,
};
// This takes the max of `min_content`, `max_content`, and
// intrinsic percentage width as described above.
let cell_measure = &self.cell_measures[row_index][column_index];
column_measure
.content_sizes
.max_assign(cell_measure.content_sizes);
column_measure.percentage_width = Percentage(
column_measure
.percentage_width
.0
.max(cell_measure.percentage_width.0),
);
}
column_measures.push(column_measure);
}
// Now we have the base computation complete, so iteratively take into account cells
// with higher colspan. Using `next_span_n` we can skip over span counts that don't
// correspond to any cells.
while next_span_n < usize::MAX {
(next_span_n, column_measures) = self
.compute_content_sizes_for_columns_with_span_up_to_n(next_span_n, &column_measures);
}
// > intrinsic percentage width of a column:
// > the smaller of:
// > * the intrinsic percentage width of the column based on cells of span up to N,
// > where N is the number of columns in the table
// > * 100% minus the sum of the intrinsic percentage width of all prior columns in
// > the table (further left when direction is "ltr" (right for "rtl"))
let mut total_intrinsic_percentage_width = 0.;
for column_index in 0..self.table.size.width {
let column_measure = &mut column_measures[column_index];
let final_intrinsic_percentage_width = column_measure
.percentage_width
.0
.min(100. - total_intrinsic_percentage_width);
total_intrinsic_percentage_width += final_intrinsic_percentage_width;
column_measure.percentage_width = Percentage(final_intrinsic_percentage_width);
}
self.column_measures = column_measures;
}
fn compute_content_sizes_for_columns_with_span_up_to_n(
&self,
n: usize,
old_column_measures: &[CellOrColumnMeasure],
) -> (usize, Vec<CellOrColumnMeasure>) {
let mut next_span_n = usize::MAX;
let mut new_content_sizes_for_columns = Vec::new();
for column_index in 0..self.table.size.width {
let old_column_measure = &old_column_measures[column_index];
let mut new_column_content_sizes = ContentSizes::zero();
let mut new_column_intrinsic_percentage_width = Percentage(0.);
for row_index in 0..self.table.size.height {
let coords = TableSlotCoordinates::new(column_index, row_index);
let resolved_coords = match self.table.resolve_first_cell_coords(coords) {
Some(resolved_coords) => resolved_coords,
None => continue,
};
let cell = match self.table.resolve_first_cell(resolved_coords) {
Some(cell) if cell.colspan <= n => cell,
Some(cell) => {
next_span_n = next_span_n.min(cell.colspan);
continue;
},
_ => continue,
};
let cell_measures = &self.cell_measures[resolved_coords.y][resolved_coords.x];
let cell_inline_content_sizes = cell_measures.content_sizes;
let columns_spanned = resolved_coords.x..resolved_coords.x + cell.colspan;
let baseline_content_sizes: ContentSizes = columns_spanned.clone().fold(
ContentSizes::zero(),
|total: ContentSizes, spanned_column_index| {
total + old_column_measures[spanned_column_index].content_sizes
},
);
// TODO: Take into account border spacing.
let old_column_content_size = old_column_measure.content_sizes;
// > **min-content width of a column based on cells of span up to N (N > 1)**
// >
// > the largest of the min-content width of the column based on cells of span up to
// > N-1 and the contributions of the cells in the column whose colSpan is N, where
// > the contribution of a cell is the result of taking the following steps:
// >
// > 1. Define the baseline min-content width as the sum of the max-content
// > widths based on cells of span up to N-1 of all columns that the cell spans.
//
// Note: This definition is likely a typo, so we use the sum of the min-content
// widths here instead.
let baseline_min_content_width = baseline_content_sizes.min_content;
let baseline_max_content_width = baseline_content_sizes.max_content;
// > 2. Define the baseline border spacing as the sum of the horizontal
// > border-spacing for any columns spanned by the cell, other than the one in
// > which the cell originates.
//
// TODO: Take into account border spacing.
// > 3. The contribution of the cell is the sum of:
// > a. the min-content width of the column based on cells of span up to N-1
let a = old_column_content_size.min_content;
// > b. the product of:
// > - the ratio of:
// > - the max-content width of the column based on cells of span up
// > to N-1 of the column minus the min-content width of the
// > column based on cells of span up to N-1 of the column, to
// > - the baseline max-content width minus the baseline min-content
// > width
// > or zero if this ratio is undefined, and
// > - the outer min-content width of the cell minus the baseline
// > min-content width and the baseline border spacing, clamped to be
// > at least 0 and at most the difference between the baseline
// > max-content width and the baseline min-content width
//
// TODO: Take into account border spacing.
let old_content_size_difference =
old_column_content_size.max_content - old_column_content_size.min_content;
let baseline_difference = baseline_min_content_width - baseline_max_content_width;
let mut b =
old_content_size_difference.to_f32_px() / baseline_difference.to_f32_px();
if !b.is_finite() {
b = 0.0;
}
let b = (cell_inline_content_sizes.min_content -
baseline_content_sizes.min_content)
.clamp_between_extremums(Au::zero(), Some(baseline_difference))
.scale_by(b);
// > c. the product of:
// > - the ratio of the max-content width based on cells of span up to
// > N-1 of the column to the baseline max-content width
// > - the outer min-content width of the cell minus the baseline
// > max-content width and baseline border spacing, or 0 if this is
// > negative
let c = (cell_inline_content_sizes.min_content -
baseline_content_sizes.max_content)
.min(Au::zero())
.scale_by(
old_column_content_size.max_content.to_f32_px() /
baseline_content_sizes.max_content.to_f32_px(),
);
let new_column_min_content_width = a + b + c;
// > **max-content width of a column based on cells of span up to N (N > 1)**
// >
// > The largest of the max-content width based on cells of span up to N-1 and the
// > contributions of the cells in the column whose colSpan is N, where the
// > contribution of a cell is the result of taking the following steps:
// > 1. Define the baseline max-content width as the sum of the max-content
// > widths based on cells of span up to N-1 of all columns that the cell spans.
//
// This is calculated above for the min-content width.
// > 2. Define the baseline border spacing as the sum of the horizontal
// > border-spacing for any columns spanned by the cell, other than the one in
// > which the cell originates.
//
// TODO: Take into account. border spacing.
// > 3. The contribution of the cell is the sum of:
// > a. the max-content width of the column based on cells of span up to N-1
let a = old_column_content_size.max_content;
// > b. the product of:
// > 1. the ratio of the max-content width based on cells of span up to
// > N-1 of the column to the baseline max-content width
let b_1 = old_column_content_size.max_content.to_f32_px() /
baseline_content_sizes.max_content.to_f32_px();
// > 2. the outer max-content width of the cell minus the baseline
// > max-content width and the baseline border spacing, or 0 if this
// > is negative
//
// TODO: Take into account. border spacing.
let b_2 = (cell_inline_content_sizes.max_content -
baseline_content_sizes.max_content)
.min(Au::zero());
let b = b_2.scale_by(b_1);
let new_column_max_content_width = a + b + c;
// The computed values for the column are always the largest of any processed cell
// in that column.
new_column_content_sizes.max_assign(ContentSizes {
min_content: new_column_min_content_width,
max_content: new_column_max_content_width,
});
// > If the intrinsic percentage width of a column based on cells of span up to N-1 is
// > greater than 0%, then the intrinsic percentage width of the column based on cells
// > of span up to N is the same as the intrinsic percentage width of the column based
// > on cells of span up to N-1.
// > Otherwise, it is the largest of the contributions of the cells in the column
// > whose colSpan is N, where the contribution of a cell is the result of taking
// > the following steps:
if old_column_measure.percentage_width.0 <= 0. &&
cell_measures.percentage_width.0 != 0.
{
// > 1. Start with the percentage contribution of the cell.
// > 2. Subtract the intrinsic percentage width of the column based on cells
// > of span up to N-1 of all columns that the cell spans. If this gives a
// > negative result, change it to 0%.
let mut spanned_columns_with_zero = 0;
let other_column_percentages_sum =
(columns_spanned).fold(0., |sum, spanned_column_index| {
let spanned_column_percentage =
old_column_measures[spanned_column_index].percentage_width;
if spanned_column_percentage.0 == 0. {
spanned_columns_with_zero += 1;
}
sum + spanned_column_percentage.0
});
let step_2 = (cell_measures.percentage_width -
Percentage(other_column_percentages_sum))
.clamp_to_non_negative();
// > Multiply by the ratio of:
// > 1. the column’s non-spanning max-content width to
// > 2. the sum of the non-spanning max-content widths of all columns
// > spanned by the cell that have an intrinsic percentage width of the column
// > based on cells of span up to N-1 equal to 0%.
// > However, if this ratio is undefined because the denominator is zero,
// > instead use the 1 divided by the number of columns spanned by the cell
// > that have an intrinsic percentage width of the column based on cells of
// > span up to N-1 equal to zero.
let step_3 = step_2.0 * (1.0 / spanned_columns_with_zero as f32);
new_column_intrinsic_percentage_width =
Percentage(new_column_intrinsic_percentage_width.0.max(step_3));
}
}
new_content_sizes_for_columns.push(CellOrColumnMeasure {
content_sizes: new_column_content_sizes,
percentage_width: new_column_intrinsic_percentage_width,
});
}
(next_span_n, new_content_sizes_for_columns)
}
fn compute_table_width(&mut self, containing_block: &ContainingBlock) {
// https://drafts.csswg.org/css-tables/#gridmin:
// > The row/column-grid width minimum (GRIDMIN) width is the sum of the min-content width of
// > all the columns plus cell spacing or borders.
// https://drafts.csswg.org/css-tables/#gridmax:
// > The row/column-grid width maximum (GRIDMAX) width is the sum of the max-content width of
// > all the columns plus cell spacing or borders.
let grid_min_and_max = self
.column_measures
.iter()
.fold(ContentSizes::zero(), |result, measure| {
result + measure.content_sizes
});
self.pbm = self.table.style.padding_border_margin(containing_block);
let content_box_size = self
@ -95,7 +562,9 @@ impl<'a> TableLayout<'a> {
// https://drafts.csswg.org/css-tables/#used-min-width-of-table
// > The used min-width of a table is the greater of the resolved min-width, CAPMIN, and GRIDMIN.
let used_min_width_of_table = grid_min_inline_size.max(min_content_sizes.inline.into());
let used_min_width_of_table = grid_min_and_max
.min_content
.max(min_content_sizes.inline.into());
// https://drafts.csswg.org/css-tables/#used-width-of-table
// > The used width of a table depends on the columns and captions widths as follows:
@ -106,24 +575,20 @@ impl<'a> TableLayout<'a> {
// > the table’s containing block width), the used min-width of the table.
let used_width_of_table = match content_box_size.inline {
LengthPercentage(length_percentage) => {
length_percentage.max(used_min_width_of_table.into())
Au::from(length_percentage).max(used_min_width_of_table)
},
Auto => grid_max_inline_size
Auto => grid_min_and_max
.max_content
.min(containing_block.inline_size.into())
.max(used_min_width_of_table)
.into(),
.max(used_min_width_of_table),
};
self.assignable_width = used_width_of_table.into();
self.assignable_width = used_width_of_table;
}
/// Distribute width to columns, performing step 2.4 of table layout from
/// <https://drafts.csswg.org/css-tables/#table-layout-algorithm>.
fn distribute_width_to_columns(
&self,
column_content_sizes: Vec<ContentSizes>,
containing_block: &ContainingBlock,
) -> Vec<Au> {
fn distribute_width_to_columns(&self) -> Vec<Au> {
if self.table.slots.is_empty() {
return Vec::new();
}
@ -162,41 +627,27 @@ impl<'a> TableLayout<'a> {
let mut max_content_sizing_guesses = Vec::new();
for column_idx in 0..self.table.size.width {
let coords = TableSlotCoordinates::new(column_idx, 0);
let cell = match self.table.resolve_first_cell(coords) {
Some(cell) => cell,
None => {
min_content_sizing_guesses.push(Au::zero());
min_content_percentage_sizing_guesses.push(Au::zero());
min_content_specified_sizing_guesses.push(Au::zero());
max_content_sizing_guesses.push(Au::zero());
continue;
},
};
use style::Zero;
let inline_size = cell
.style
.box_size(containing_block.style.writing_mode)
.inline;
let min_and_max_content = &column_content_sizes[column_idx];
let min_content_width = min_and_max_content.min_content;
let max_content_width = min_and_max_content.max_content;
let column_measure = &self.column_measures[column_idx];
let min_content_width = column_measure.content_sizes.min_content;
let max_content_width = column_measure.content_sizes.max_content;
let constrained = self.column_constrainedness[column_idx];
let (
min_content_percentage_sizing_guess,
min_content_specified_sizing_guess,
max_content_sizing_guess,
) = match inline_size {
LengthPercentage(length_percentage) if length_percentage.has_percentage() => {
let percent_guess = min_content_width.max(
length_percentage
.resolve(self.assignable_width.into())
.into(),
);
(percent_guess, percent_guess, percent_guess)
},
LengthPercentage(_) => (min_content_width, max_content_width, max_content_width),
Auto => (min_content_width, min_content_width, max_content_width),
) = if !column_measure.percentage_width.is_zero() {
let resolved = self
.assignable_width
.scale_by(column_measure.percentage_width.0);
let percent_guess = min_content_width.max(resolved.into());
(percent_guess, percent_guess, percent_guess)
} else if constrained {
(min_content_width, max_content_width, max_content_width)
} else {
(min_content_width, min_content_width, max_content_width)
};
min_content_sizing_guesses.push(min_content_width);
@ -284,17 +735,143 @@ impl<'a> TableLayout<'a> {
)
}
fn distribute_extra_width_to_columns(
&self,
max_content_sizing_guesses: &mut Vec<Au>,
max_content_sum: Au,
) {
// The simplest distribution algorithm, until we have support for proper extra space
// distribution is to equally distribute the extra space.
let ratio_factor = 1.0 / max_content_sizing_guesses.len() as f32;
/// This is an implementation of *Distributing excess width to columns* from
/// <https://drafts.csswg.org/css-tables/#distributing-width-to-columns>.
fn distribute_extra_width_to_columns(&self, column_sizes: &mut Vec<Au>, column_sizes_sum: Au) {
let all_columns = 0..self.table.size.width;
let extra_inline_size = self.assignable_width - column_sizes_sum;
let has_originating_cells =
|column_index: &usize| self.column_has_originating_cell[*column_index];
let is_constrained = |column_index: &usize| self.column_constrainedness[*column_index];
let is_unconstrained = |column_index: &usize| !is_constrained(column_index);
let has_percent_greater_than_zero =
|column_index: &usize| self.column_measures[*column_index].percentage_width.0 > 0.;
let has_percent_zero = |column_index: &usize| !has_percent_greater_than_zero(column_index);
let has_max_content = |column_index: &usize| {
self.column_measures[*column_index]
.content_sizes
.max_content !=
Au(0)
};
let max_content_sum =
|column_index: usize| self.column_measures[column_index].content_sizes.max_content;
// > If there are non-constrained columns that have originating cells with intrinsic
// > percentage width of 0% and with nonzero max-content width (aka the columns allowed to
// > grow by this rule), the distributed widths of the columns allowed to grow by this rule
// > are increased in proportion to max-content width so the total increase adds to the
// > excess width.
let unconstrained_max_content_columns = all_columns
.clone()
.filter(is_unconstrained)
.filter(has_originating_cells)
.filter(has_percent_zero)
.filter(has_max_content);
let total_max_content_width = unconstrained_max_content_columns
.clone()
.map(max_content_sum)
.fold(Au::zero(), |a, b| a + b);
if total_max_content_width != Au::zero() {
for column_index in unconstrained_max_content_columns {
column_sizes[column_index] += extra_inline_size.scale_by(
self.column_measures[column_index]
.content_sizes
.max_content
.to_f32_px() /
total_max_content_width.to_f32_px(),
);
}
return;
}
// > Otherwise, if there are non-constrained columns that have originating cells with intrinsic
// > percentage width of 0% (aka the columns allowed to grow by this rule, which thanks to the
// > previous rule must have zero max-content width), the distributed widths of the columns
// > allowed to grow by this rule are increased by equal amounts so the total increase adds to
// > the excess width.V
let unconstrained_no_percent_columns = all_columns
.clone()
.filter(is_unconstrained)
.filter(has_originating_cells)
.filter(has_percent_zero);
let total_unconstrained_no_percent = unconstrained_no_percent_columns.clone().count();
if total_unconstrained_no_percent > 0 {
let extra_space_per_column =
extra_inline_size.scale_by(1.0 / total_unconstrained_no_percent as f32);
for column_index in unconstrained_no_percent_columns {
column_sizes[column_index] += extra_space_per_column;
}
return;
}
// > Otherwise, if there are constrained columns with intrinsic percentage width of 0% and
// > with nonzero max-content width (aka the columns allowed to grow by this rule, which, due
// > to other rules, must have originating cells), the distributed widths of the columns
// > allowed to grow by this rule are increased in proportion to max-content width so the
// > total increase adds to the excess width.
let constrained_max_content_columns = all_columns
.clone()
.filter(is_constrained)
.filter(has_originating_cells)
.filter(has_percent_zero)
.filter(has_max_content);
let total_max_content_width = constrained_max_content_columns
.clone()
.map(max_content_sum)
.fold(Au::zero(), |a, b| a + b);
if total_max_content_width != Au::zero() {
for column_index in constrained_max_content_columns {
column_sizes[column_index] += extra_inline_size.scale_by(
self.column_measures[column_index]
.content_sizes
.max_content
.to_f32_px() /
total_max_content_width.to_f32_px(),
);
}
return;
}
// > Otherwise, if there are columns with intrinsic percentage width greater than 0% (aka the
// > columns allowed to grow by this rule, which, due to other rules, must have originating
// > cells), the distributed widths of the columns allowed to grow by this rule are increased
// > in proportion to intrinsic percentage width so the total increase adds to the excess
// > width.
let columns_with_percentage = all_columns.clone().filter(has_percent_greater_than_zero);
let total_percent = columns_with_percentage
.clone()
.map(|column_index| self.column_measures[column_index].percentage_width.0)
.sum::<f32>();
if total_percent > 0. {
for column_index in columns_with_percentage {
column_sizes[column_index] += extra_inline_size.scale_by(
self.column_measures[column_index].percentage_width.0 / total_percent,
);
}
return;
}
// > Otherwise, if there is any such column, the distributed widths of all columns that have
// > originating cells are increased by equal amounts so the total increase adds to the excess
// > width.
let has_originating_cells_columns = all_columns.clone().filter(has_originating_cells);
let total_has_originating_cells = has_originating_cells_columns.clone().count();
if total_has_originating_cells > 0 {
let extra_space_per_column =
extra_inline_size.scale_by(1.0 / total_has_originating_cells as f32);
for column_index in has_originating_cells_columns {
column_sizes[column_index] += extra_space_per_column;
}
return;
}
// > Otherwise, the distributed widths of all columns are increased by equal amounts so the
// total increase adds to the excess width.
let extra_space_for_all_columns =
(self.assignable_width - max_content_sum).scale_by(ratio_factor);
for guess in max_content_sizing_guesses.iter_mut() {
extra_inline_size.scale_by(1.0 / self.table.size.width as f32);
for guess in column_sizes.iter_mut() {
*guess += extra_space_for_all_columns;
}
}
@ -319,7 +896,7 @@ impl<'a> TableLayout<'a> {
let mut total_width = Au::zero();
for width_index in column_index..column_index + cell.colspan {
total_width += self.column_sizes[width_index];
total_width += self.distributed_column_widths[width_index];
}
let border = cell.style.border_width(containing_block.style.writing_mode);
@ -393,7 +970,7 @@ impl<'a> TableLayout<'a> {
positioning_context: &mut PositioningContext,
) -> (Vec<Fragment>, Au) {
assert_eq!(self.table.size.height, self.row_sizes.len());
assert_eq!(self.table.size.width, self.column_sizes.len());
assert_eq!(self.table.size.width, self.distributed_column_widths.len());
let mut fragments = Vec::new();
let mut row_offset = Au::zero();
@ -402,7 +979,7 @@ impl<'a> TableLayout<'a> {
let row_size = self.row_sizes[row_index];
for column_index in 0..self.table.size.width {
let column_size = self.column_sizes[column_index];
let column_size = self.distributed_column_widths[column_index];
let layout = match self.cells_laid_out[row_index][column_index].take() {
Some(layout) => layout,
None => continue,
@ -463,19 +1040,27 @@ impl Table {
&self,
layout_context: &LayoutContext,
writing_mode: WritingMode,
) -> (ContentSizes, Vec<ContentSizes>) {
let mut final_size = ContentSizes::zero();
let column_content_sizes = (0..self.size.width)
.map(|column_idx| {
let coords = TableSlotCoordinates::new(column_idx, 0);
) -> (ContentSizes, Vec<Vec<ContentSizes>>) {
let mut total_size = ContentSizes::zero();
let mut inline_content_sizes = Vec::new();
for column_index in 0..self.size.width {
let mut row_inline_content_sizes = Vec::new();
let mut max_content_sizes_in_column = ContentSizes::zero();
for row_index in 0..self.size.width {
// TODO: Take into account padding and border here.
let coords = TableSlotCoordinates::new(column_index, row_index);
let content_sizes =
self.inline_content_sizes_for_cell_at(coords, layout_context, writing_mode);
final_size.min_content += content_sizes.min_content;
final_size.max_content += content_sizes.max_content;
content_sizes
})
.collect();
(final_size, column_content_sizes)
max_content_sizes_in_column.max_assign(content_sizes);
row_inline_content_sizes.push(content_sizes);
}
inline_content_sizes.push(row_inline_content_sizes);
total_size += max_content_sizes_in_column;
}
(total_size, inline_content_sizes)
}
pub(crate) fn inline_content_sizes(