/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
//! CSS tables.
//!
//! This follows the "More Precise Definitions of Inline Layout and Table Layout" proposal written
//! by L. David Baron (Mozilla) here:
//!
//! http://dbaron.org/css/intrinsic/
//!
//! Hereafter this document is referred to as INTRINSIC.
#![deny(unsafe_code)]
use block::{BlockFlow, BlockNonReplaced, FloatNonReplaced, ISizeAndMarginsComputer};
use block::{MarginsMayCollapseFlag};
use context::LayoutContext;
use floats::FloatKind;
use flow::{FlowClass, Flow, ImmutableFlowUtils};
use flow::{IMPACTED_BY_LEFT_FLOATS, IMPACTED_BY_RIGHT_FLOATS};
use fragment::{Fragment, FragmentBorderBoxIterator};
use table::{ChildInlineSizeInfo, ColumnComputedInlineSize, ColumnIntrinsicInlineSize};
use wrapper::ThreadSafeLayoutNode;
use geom::{Point2D, Rect};
use util::geometry::Au;
use std::cmp::{max, min};
use std::fmt;
use std::ops::Add;
use std::sync::Arc;
use style::computed_values::table_layout;
use style::properties::ComputedValues;
use style::values::CSSFloat;
use style::values::computed::LengthOrPercentageOrAuto;
#[derive(Copy, RustcEncodable, Debug)]
pub enum TableLayout {
Fixed,
Auto
}
/// A table wrapper flow based on a block formatting context.
#[derive(RustcEncodable)]
pub struct TableWrapperFlow {
pub block_flow: BlockFlow,
/// Intrinsic column inline sizes according to INTRINSIC § 4.1
pub column_intrinsic_inline_sizes: Vec<ColumnIntrinsicInlineSize>,
/// Table-layout property
pub table_layout: TableLayout,
}
impl TableWrapperFlow {
pub fn from_node_and_fragment(node: &ThreadSafeLayoutNode,
fragment: Fragment)
-> TableWrapperFlow {
let mut block_flow = BlockFlow::from_node_and_fragment(node, fragment);
let table_layout = if block_flow.fragment().style().get_table().table_layout ==
table_layout::T::fixed {
TableLayout::Fixed
} else {
TableLayout::Auto
};
TableWrapperFlow {
block_flow: block_flow,
column_intrinsic_inline_sizes: vec!(),
table_layout: table_layout
}
}
pub fn float_from_node_and_fragment(node: &ThreadSafeLayoutNode,
fragment: Fragment,
float_kind: FloatKind)
-> TableWrapperFlow {
let mut block_flow = BlockFlow::float_from_node_and_fragment(node, fragment, float_kind);
let table_layout = if block_flow.fragment().style().get_table().table_layout ==
table_layout::T::fixed {
TableLayout::Fixed
} else {
TableLayout::Auto
};
TableWrapperFlow {
block_flow: block_flow,
column_intrinsic_inline_sizes: vec!(),
table_layout: table_layout
}
}
/// Calculates table column sizes for automatic layout per INTRINSIC § 4.3.
fn calculate_table_column_sizes_for_automatic_layout(
&mut self,
intermediate_column_inline_sizes: &mut [IntermediateColumnInlineSize]) {
// Find the padding and border of our first child, which is the table itself.
//
// This is a little weird because we're computing border/padding/margins for our child,
// when normally the child computes it itself. But it has to be this way because the
// padding will affect where we place the child. This is an odd artifact of the way that
// tables are separated into table flows and table wrapper flows.
let mut available_inline_size = self.block_flow.fragment.border_box.size.inline;
let (mut table_border_padding, mut spacing) = (Au(0), Au(0));
for kid in self.block_flow.base.child_iter() {
if kid.is_table() {
let kid_block = kid.as_block();
let spacing_per_cell = kid_block.fragment
.style()
.get_inheritedtable()
.border_spacing
.horizontal;
spacing = spacing_per_cell * (self.column_intrinsic_inline_sizes.len() as i32 + 1);
available_inline_size = self.block_flow.fragment.border_box.size.inline;
kid_block.fragment.compute_border_and_padding(available_inline_size);
kid_block.fragment.compute_block_direction_margins(available_inline_size);
kid_block.fragment.compute_inline_direction_margins(available_inline_size);
table_border_padding = kid_block.fragment.border_padding.inline_start_end();
break
}
}
// FIXME(pcwalton, spec): INTRINSIC § 8 does not properly define how to compute this, but
// says "the basic idea is the same as the shrink-to-fit width that CSS2.1 defines". So we
// just use the shrink-to-fit inline size.
let mut available_inline_size =
match self.block_flow.fragment.style().content_inline_size() {
LengthOrPercentageOrAuto::Auto => {
self.block_flow.get_shrink_to_fit_inline_size(available_inline_size)
}
// FIXME(mttr): This fixes #4421 without breaking our current reftests, but I'm
// not completely sure this is "correct".
//
// That said, `available_inline_size` is, as far as I can tell, equal to the
// table's computed width property (W) and is used from this point forward in a way
// that seems to correspond with CSS 2.1 § 17.5.2.2 under "Column and caption
// widths influence the final table width as follows: …"
_ => available_inline_size,
};
available_inline_size = available_inline_size - spacing;
// Compute all the guesses for the column sizes, and sum them.
let mut total_guess = AutoLayoutCandidateGuess::new();
let guesses: Vec<AutoLayoutCandidateGuess> =
self.column_intrinsic_inline_sizes.iter().map(|column_intrinsic_inline_size| {
let guess = AutoLayoutCandidateGuess::from_column_intrinsic_inline_size(
column_intrinsic_inline_size,
available_inline_size);
total_guess = &total_guess + &guess;
guess
}).collect();
// Assign inline sizes.
let selection = SelectedAutoLayoutCandidateGuess::select(&total_guess,
available_inline_size);
let mut total_used_inline_size = Au(0);
for (intermediate_column_inline_size, guess) in
intermediate_column_inline_sizes.iter_mut().zip(guesses.iter()) {
intermediate_column_inline_size.size = guess.calculate(selection);
intermediate_column_inline_size.percentage = 0.0;
total_used_inline_size = total_used_inline_size + intermediate_column_inline_size.size
}
// Distribute excess inline-size if necessary per INTRINSIC § 4.4.
//
// FIXME(pcwalton, spec): How do I deal with fractional excess?
let excess_inline_size = available_inline_size - total_used_inline_size;
if excess_inline_size > Au(0) && selection ==
SelectedAutoLayoutCandidateGuess::UsePreferredGuessAndDistributeExcessInlineSize {
let mut info = ExcessInlineSizeDistributionInfo::new();
for column_intrinsic_inline_size in self.column_intrinsic_inline_sizes.iter() {
info.update(column_intrinsic_inline_size)
}
let mut total_distributed_excess_size = Au(0);
for (intermediate_column_inline_size, column_intrinsic_inline_size) in
intermediate_column_inline_sizes.iter_mut()
.zip(self.column_intrinsic_inline_sizes
.iter()) {
info.distribute_excess_inline_size_to_column(intermediate_column_inline_size,
column_intrinsic_inline_size,
excess_inline_size,
&mut total_distributed_excess_size)
}
total_used_inline_size = available_inline_size
}
self.block_flow.fragment.border_box.size.inline = total_used_inline_size +
table_border_padding + spacing;
self.block_flow.base.position.size.inline = total_used_inline_size +
table_border_padding + spacing + self.block_flow.fragment.margin.inline_start_end();
}
fn compute_used_inline_size(&mut self,
layout_context: &LayoutContext,
parent_flow_inline_size: Au) {
// Delegate to the appropriate inline size computer to find the constraint inputs.
let input = if self.block_flow.base.flags.is_float() {
FloatNonReplaced.compute_inline_size_constraint_inputs(&mut self.block_flow,
parent_flow_inline_size,
layout_context)
} else {
BlockNonReplaced.compute_inline_size_constraint_inputs(&mut self.block_flow,
parent_flow_inline_size,
layout_context)
};
// Delegate to the appropriate inline size computer to write the constraint solutions in.
if self.block_flow.base.flags.is_float() {
let solution = FloatNonReplaced.solve_inline_size_constraints(&mut self.block_flow,
&input);
FloatNonReplaced.set_inline_size_constraint_solutions(&mut self.block_flow, solution);
FloatNonReplaced.set_flow_x_coord_if_necessary(&mut self.block_flow, solution);
} else {
let solution = BlockNonReplaced.solve_inline_size_constraints(&mut self.block_flow,
&input);
BlockNonReplaced.set_inline_size_constraint_solutions(&mut self.block_flow, solution);
BlockNonReplaced.set_flow_x_coord_if_necessary(&mut self.block_flow, solution);
}
}
}
impl Flow for TableWrapperFlow {
fn class(&self) -> FlowClass {
FlowClass::TableWrapper
}
fn as_table_wrapper<'a>(&'a mut self) -> &'a mut TableWrapperFlow {
self
}
fn as_immutable_table_wrapper<'a>(&'a self) -> &'a TableWrapperFlow {
self
}
fn as_block<'a>(&'a mut self) -> &'a mut BlockFlow {
&mut self.block_flow
}
fn bubble_inline_sizes(&mut self) {
// Get the intrinsic column inline-sizes info from the table flow.
for kid in self.block_flow.base.child_iter() {
debug_assert!(kid.is_table_caption() || kid.is_table());
if kid.is_table() {
self.column_intrinsic_inline_sizes = kid.column_intrinsic_inline_sizes().clone()
}
}
self.block_flow.bubble_inline_sizes();
}
fn assign_inline_sizes(&mut self, layout_context: &LayoutContext) {
debug!("assign_inline_sizes({}): assigning inline_size for flow",
if self.block_flow.base.flags.is_float() {
"floated table_wrapper"
} else {
"table_wrapper"
});
let mut intermediate_column_inline_sizes = self.column_intrinsic_inline_sizes
.iter()
.map(|column_intrinsic_inline_size| {
IntermediateColumnInlineSize {
size: column_intrinsic_inline_size.minimum_length,
percentage: column_intrinsic_inline_size.percentage,
}
}).collect::<Vec<_>>();
// Table wrappers are essentially block formatting contexts and are therefore never
// impacted by floats.
self.block_flow.base.flags.remove(IMPACTED_BY_LEFT_FLOATS);
self.block_flow.base.flags.remove(IMPACTED_BY_RIGHT_FLOATS);
// Our inline-size was set to the inline-size of the containing block by the flow's parent.
// Now compute the real value.
let containing_block_inline_size = self.block_flow.base.block_container_inline_size;
if self.block_flow.base.flags.is_float() {
self.block_flow.float.as_mut().unwrap().containing_inline_size =
containing_block_inline_size;
}
self.compute_used_inline_size(layout_context, containing_block_inline_size);
match self.table_layout {
TableLayout::Fixed => {}
TableLayout::Auto => {
self.calculate_table_column_sizes_for_automatic_layout(
intermediate_column_inline_sizes.as_mut_slice())
}
}
let inline_start_content_edge = self.block_flow.fragment.border_box.start.i;
let content_inline_size = self.block_flow.fragment.border_box.size.inline;
// FIXME (mbrubeck): Test mixed RTL/LTR table layout, make sure this is right.
let inline_end_content_edge = self.block_flow.base.block_container_inline_size -
self.block_flow.fragment.margin.inline_end -
content_inline_size -
inline_start_content_edge;
// In case of fixed layout, column inline-sizes are calculated in table flow.
let assigned_column_inline_sizes = match self.table_layout {
TableLayout::Fixed => None,
TableLayout::Auto => {
Some(intermediate_column_inline_sizes.iter().map(|sizes| {
ColumnComputedInlineSize {
size: sizes.size,
}
}).collect::<Vec<_>>())
}
};
match assigned_column_inline_sizes {
None => {
self.block_flow.propagate_assigned_inline_size_to_children(
layout_context,
inline_start_content_edge,
inline_end_content_edge,
content_inline_size,
None)
}
Some(ref assigned_column_inline_sizes) => {
let info = ChildInlineSizeInfo {
column_computed_inline_sizes: assigned_column_inline_sizes.as_slice(),
spacing: self.block_flow.fragment.style().get_inheritedtable().border_spacing,
};
self.block_flow
.propagate_assigned_inline_size_to_children(layout_context,
inline_start_content_edge,
inline_end_content_edge,
content_inline_size,
Some(info));
}
}
}
fn assign_block_size<'a>(&mut self, ctx: &'a LayoutContext<'a>) {
debug!("assign_block_size: assigning block_size for table_wrapper");
self.block_flow.assign_block_size_block_base(ctx, MarginsMayCollapseFlag::MarginsMayNotCollapse);
}
fn compute_absolute_position(&mut self) {
self.block_flow.compute_absolute_position()
}
fn place_float_if_applicable<'a>(&mut self, layout_context: &'a LayoutContext<'a>) {
self.block_flow.place_float_if_applicable(layout_context)
}
fn assign_block_size_for_inorder_child_if_necessary<'a>(&mut self,
layout_context: &'a LayoutContext<'a>,
parent_thread_id: u8)
-> bool {
if self.block_flow.base.flags.is_float() {
self.block_flow.place_float();
return true
}
let impacted = self.block_flow.base.flags.impacted_by_floats();
if impacted {
self.block_flow.base.thread_id = parent_thread_id;
self.assign_block_size(layout_context);
}
impacted
}
fn update_late_computed_inline_position_if_necessary(&mut self, inline_position: Au) {
self.block_flow.update_late_computed_inline_position_if_necessary(inline_position)
}
fn update_late_computed_block_position_if_necessary(&mut self, block_position: Au) {
self.block_flow.update_late_computed_block_position_if_necessary(block_position)
}
fn build_display_list(&mut self, layout_context: &LayoutContext) {
self.block_flow.build_display_list(layout_context)
}
fn repair_style(&mut self, new_style: &Arc<ComputedValues>) {
self.block_flow.repair_style(new_style)
}
fn compute_overflow(&self) -> Rect<Au> {
self.block_flow.compute_overflow()
}
fn iterate_through_fragment_border_boxes(&self,
iterator: &mut FragmentBorderBoxIterator,
stacking_context_position: &Point2D<Au>) {
self.block_flow.iterate_through_fragment_border_boxes(iterator, stacking_context_position)
}
fn mutate_fragments(&mut self, mutator: &mut FnMut(&mut Fragment)) {
self.block_flow.mutate_fragments(mutator)
}
}
impl fmt::Debug for TableWrapperFlow {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
if self.block_flow.base.flags.is_float() {
write!(f, "TableWrapperFlow(Float): {:?}", self.block_flow.fragment)
} else {
write!(f, "TableWrapperFlow: {:?}", self.block_flow.fragment)
}
}
}
/// The layout "guesses" defined in INTRINSIC § 4.3.
struct AutoLayoutCandidateGuess {
/// The column inline-size assignment where each column is assigned its intrinsic minimum
/// inline-size.
minimum_guess: Au,
/// The column inline-size assignment where:
/// * A column with an intrinsic percentage inline-size greater than 0% is assigned the
/// larger of:
/// - Its intrinsic percentage inline-size times the assignable inline-size;
/// - Its intrinsic minimum inline-size;
/// * Other columns receive their intrinsic minimum inline-size.
minimum_percentage_guess: Au,
/// The column inline-size assignment where:
/// * Each column with an intrinsic percentage inline-size greater than 0% is assigned the
/// larger of:
/// - Its intrinsic percentage inline-size times the assignable inline-size;
/// - Its intrinsic minimum inline-size;
/// * Any other column that is constrained is assigned its intrinsic preferred inline-size;
/// * Other columns are assigned their intrinsic minimum inline-size.
minimum_specified_guess: Au,
/// The column inline-size assignment where:
/// * Each column with an intrinsic percentage inline-size greater than 0% is assigned the
/// larger of:
/// - Its intrinsic percentage inline-size times the assignable inline-size;
/// - Its intrinsic minimum inline-size;
/// * Other columns are assigned their intrinsic preferred inline-size.
preferred_guess: Au,
}
impl AutoLayoutCandidateGuess {
/// Creates a guess with all elements initialized to zero.
fn new() -> AutoLayoutCandidateGuess {
AutoLayoutCandidateGuess {
minimum_guess: Au(0),
minimum_percentage_guess: Au(0),
minimum_specified_guess: Au(0),
preferred_guess: Au(0),
}
}
/// Fills in the inline-size guesses for this column per INTRINSIC § 4.3.
fn from_column_intrinsic_inline_size(column_intrinsic_inline_size: &ColumnIntrinsicInlineSize,
assignable_inline_size: Au)
-> AutoLayoutCandidateGuess {
let minimum_percentage_guess =
max(assignable_inline_size.scale_by(column_intrinsic_inline_size.percentage),
column_intrinsic_inline_size.minimum_length);
AutoLayoutCandidateGuess {
minimum_guess: column_intrinsic_inline_size.minimum_length,
minimum_percentage_guess: minimum_percentage_guess,
// FIXME(pcwalton): We need the notion of *constrainedness* per INTRINSIC § 4 to
// implement this one correctly.
minimum_specified_guess: if column_intrinsic_inline_size.percentage > 0.0 {
minimum_percentage_guess
} else if column_intrinsic_inline_size.constrained {
column_intrinsic_inline_size.preferred
} else {
column_intrinsic_inline_size.minimum_length
},
preferred_guess: if column_intrinsic_inline_size.percentage > 0.0 {
minimum_percentage_guess
} else {
column_intrinsic_inline_size.preferred
},
}
}
/// Calculates the inline-size, interpolating appropriately based on the value of `selection`.
///
/// This does *not* distribute excess inline-size. That must be done later if necessary.
fn calculate(&self, selection: SelectedAutoLayoutCandidateGuess) -> Au {
match selection {
SelectedAutoLayoutCandidateGuess::UseMinimumGuess => self.minimum_guess,
SelectedAutoLayoutCandidateGuess::
InterpolateBetweenMinimumGuessAndMinimumPercentageGuess(weight) => {
interp(self.minimum_guess, self.minimum_percentage_guess, weight)
}
SelectedAutoLayoutCandidateGuess::
InterpolateBetweenMinimumPercentageGuessAndMinimumSpecifiedGuess(weight) => {
interp(self.minimum_percentage_guess, self.minimum_specified_guess, weight)
}
SelectedAutoLayoutCandidateGuess::
InterpolateBetweenMinimumSpecifiedGuessAndPreferredGuess(weight) => {
interp(self.minimum_specified_guess, self.preferred_guess, weight)
}
SelectedAutoLayoutCandidateGuess::UsePreferredGuessAndDistributeExcessInlineSize => {
self.preferred_guess
}
}
}
}
impl<'a> Add for &'a AutoLayoutCandidateGuess {
type Output = AutoLayoutCandidateGuess;
#[inline]
fn add(self, other: &AutoLayoutCandidateGuess) -> AutoLayoutCandidateGuess {
AutoLayoutCandidateGuess {
minimum_guess: self.minimum_guess + other.minimum_guess,
minimum_percentage_guess:
self.minimum_percentage_guess + other.minimum_percentage_guess,
minimum_specified_guess: self.minimum_specified_guess + other.minimum_specified_guess,
preferred_guess: self.preferred_guess + other.preferred_guess,
}
}
}
/// The `CSSFloat` member specifies the weight of the smaller of the two guesses, on a scale from
/// 0.0 to 1.0.
#[derive(Copy, PartialEq, Debug)]
enum SelectedAutoLayoutCandidateGuess {
UseMinimumGuess,
InterpolateBetweenMinimumGuessAndMinimumPercentageGuess(CSSFloat),
InterpolateBetweenMinimumPercentageGuessAndMinimumSpecifiedGuess(CSSFloat),
InterpolateBetweenMinimumSpecifiedGuessAndPreferredGuess(CSSFloat),
UsePreferredGuessAndDistributeExcessInlineSize,
}
impl SelectedAutoLayoutCandidateGuess {
/// See INTRINSIC § 4.3.
///
/// FIXME(pcwalton, INTRINSIC spec): INTRINSIC doesn't specify whether these are exclusive or
/// inclusive ranges.
fn select(guess: &AutoLayoutCandidateGuess, assignable_inline_size: Au)
-> SelectedAutoLayoutCandidateGuess {
if assignable_inline_size < guess.minimum_guess {
SelectedAutoLayoutCandidateGuess::UseMinimumGuess
} else if assignable_inline_size < guess.minimum_percentage_guess {
let weight = weight(guess.minimum_guess,
assignable_inline_size,
guess.minimum_percentage_guess);
SelectedAutoLayoutCandidateGuess::InterpolateBetweenMinimumGuessAndMinimumPercentageGuess(weight)
} else if assignable_inline_size < guess.minimum_specified_guess {
let weight = weight(guess.minimum_percentage_guess,
assignable_inline_size,
guess.minimum_specified_guess);
SelectedAutoLayoutCandidateGuess::InterpolateBetweenMinimumPercentageGuessAndMinimumSpecifiedGuess(weight)
} else if assignable_inline_size < guess.preferred_guess {
let weight = weight(guess.minimum_specified_guess,
assignable_inline_size,
guess.preferred_guess);
SelectedAutoLayoutCandidateGuess::InterpolateBetweenMinimumSpecifiedGuessAndPreferredGuess(weight)
} else {
SelectedAutoLayoutCandidateGuess::UsePreferredGuessAndDistributeExcessInlineSize
}
}
}
/// Computes the weight needed to linearly interpolate `middle` between two guesses `low` and
/// `high` as specified by INTRINSIC § 4.3.
fn weight(low: Au, middle: Au, high: Au) -> CSSFloat {
(middle - low).to_subpx() / (high - low).to_subpx()
}
/// Linearly interpolates between two guesses, as specified by INTRINSIC § 4.3.
fn interp(low: Au, high: Au, weight: CSSFloat) -> Au {
low + (high - low).scale_by(weight)
}
struct ExcessInlineSizeDistributionInfo {
preferred_inline_size_of_nonconstrained_columns_with_no_percentage: Au,
count_of_nonconstrained_columns_with_no_percentage: u32,
preferred_inline_size_of_constrained_columns_with_no_percentage: Au,
total_percentage: CSSFloat,
column_count: u32,
}
impl ExcessInlineSizeDistributionInfo {
fn new() -> ExcessInlineSizeDistributionInfo {
ExcessInlineSizeDistributionInfo {
preferred_inline_size_of_nonconstrained_columns_with_no_percentage: Au(0),
count_of_nonconstrained_columns_with_no_percentage: 0,
preferred_inline_size_of_constrained_columns_with_no_percentage: Au(0),
total_percentage: 0.0,
column_count: 0,
}
}
fn update(&mut self, column_intrinsic_inline_size: &ColumnIntrinsicInlineSize) {
if !column_intrinsic_inline_size.constrained &&
column_intrinsic_inline_size.percentage == 0.0 {
self.preferred_inline_size_of_nonconstrained_columns_with_no_percentage =
self.preferred_inline_size_of_nonconstrained_columns_with_no_percentage +
column_intrinsic_inline_size.preferred;
self.count_of_nonconstrained_columns_with_no_percentage += 1
}
if column_intrinsic_inline_size.constrained &&
column_intrinsic_inline_size.percentage == 0.0 {
self.preferred_inline_size_of_constrained_columns_with_no_percentage =
self.preferred_inline_size_of_constrained_columns_with_no_percentage +
column_intrinsic_inline_size.preferred
}
self.total_percentage += column_intrinsic_inline_size.percentage;
self.column_count += 1
}
/// Based on the information here, distributes excess inline-size to the given column per
/// INTRINSIC § 4.4.
///
/// `#[inline]` so the compiler will hoist out the branch, which is loop-invariant.
#[inline]
fn distribute_excess_inline_size_to_column(
&self,
intermediate_column_inline_size: &mut IntermediateColumnInlineSize,
column_intrinsic_inline_size: &ColumnIntrinsicInlineSize,
excess_inline_size: Au,
total_distributed_excess_size: &mut Au) {
let proportion =
if self.preferred_inline_size_of_nonconstrained_columns_with_no_percentage > Au(0) {
// FIXME(spec, pcwalton): Gecko and WebKit do *something* here when there are
// nonconstrained columns with no percentage *and* no preferred width. What do they
// do?
if !column_intrinsic_inline_size.constrained &&
column_intrinsic_inline_size.percentage == 0.0 {
column_intrinsic_inline_size.preferred.to_subpx() /
self.preferred_inline_size_of_nonconstrained_columns_with_no_percentage
.to_subpx()
} else {
0.0
}
} else if self.count_of_nonconstrained_columns_with_no_percentage > 0 {
1.0 / (self.count_of_nonconstrained_columns_with_no_percentage as CSSFloat)
} else if self.preferred_inline_size_of_constrained_columns_with_no_percentage >
Au(0) {
column_intrinsic_inline_size.preferred.to_subpx() /
self.preferred_inline_size_of_constrained_columns_with_no_percentage.to_subpx()
} else if self.total_percentage > 0.0 {
column_intrinsic_inline_size.percentage / self.total_percentage
} else {
1.0 / (self.column_count as CSSFloat)
};
// The `min` here has the effect of throwing away fractional excess at the end of the
// table.
let amount_to_distribute = min(excess_inline_size.scale_by(proportion),
excess_inline_size - *total_distributed_excess_size);
*total_distributed_excess_size = *total_distributed_excess_size + amount_to_distribute;
intermediate_column_inline_size.size = intermediate_column_inline_size.size +
amount_to_distribute
}
}
/// An intermediate column size assignment.
struct IntermediateColumnInlineSize {
size: Au,
percentage: f64,
}