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layout: Improve layout of table captions (#32695)

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- Instead of treating captions as a `BlockFormattingContext`, treat it as
  a `NonReplacedFormattingContext`, which allows reusing flow layout for
  captions -- fixing some issues with sizing.
- Pass in the proper size of the containing block when laying out,
  fixing margin calculation.
- Follow the unspecified rules about how various size properties on
  captions affect their size.
- Improve linebreaking around atomics, which is tested by
  caption-related tests. This fixes intrinsic size calculation regarding
  soft wrap opportunities around atomic and also makes the code making
  these actual soft wrap opportunities a bit better.

Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Co-authored-by: Mukilan Thiyagarajan <mukilan@igalia.com>
This commit is contained in:
Martin Robinson 2024-07-08 14:58:38 +02:00 • committed by GitHub
parent 2888193cfe
commit 89944bd330
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GPG key ID: B5690EEEBB952194
52 changed files with 225 additions and 454 deletions
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162
components/layout_2020/flow/inline/mod.rs
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@ -104,8 +104,12 @@ use style::values::specified::box_::BaselineSource;
use style::values::specified::text::{TextAlignKeyword, TextDecorationLine};
use style::values::specified::{TextAlignLast, TextJustify};
use style::Zero;
use text_run::{add_or_get_font, get_font_for_first_font_for_style, TextRun};
use text_run::{
add_or_get_font, get_font_for_first_font_for_style, TextRun, XI_LINE_BREAKING_CLASS_GL,
XI_LINE_BREAKING_CLASS_WJ, XI_LINE_BREAKING_CLASS_ZWJ,
};
use webrender_api::FontInstanceKey;
use xi_unicode::linebreak_property;
use super::float::PlacementAmongFloats;
use crate::cell::ArcRefCell;
@ -176,7 +180,10 @@ pub(crate) enum InlineItem {
TextRun(TextRun),
OutOfFlowAbsolutelyPositionedBox(ArcRefCell<AbsolutelyPositionedBox>),
OutOfFlowFloatBox(FloatBox),
Atomic(IndependentFormattingContext),
Atomic(
IndependentFormattingContext,
usize, /* offset_in_text */
),
}
/// Information about the current line under construction for a particular
@ -613,12 +620,6 @@ pub(super) struct InlineFormattingContextState<'a, 'b> {
/// is encountered.
pub have_deferred_soft_wrap_opportunity: bool,
/// Whether or not a soft wrap opportunity should be prevented before the next atomic
/// element encountered in the inline formatting context. See
/// `char_prevents_soft_wrap_opportunity_when_before_or_after_atomic` for more
/// details.
pub prevent_soft_wrap_opportunity_before_next_atomic: bool,
/// Whether or not this InlineFormattingContext has processed any in flow content at all.
had_inflow_content: bool,
@ -1202,15 +1203,11 @@ impl<'a, 'b> InlineFormattingContextState<'a, 'b> {
}
pub(super) fn defer_forced_line_break(&mut self) {
// If this hard line break happens in the middle of an unbreakable segment, there are two
// scenarios:
// 1. The current portion of the unbreakable segment fits on the current line in which
// case we commit it.
// 2. The current portion of the unbreakable segment does not fit in which case we
// need to put it on a new line *before* actually triggering the hard line break.
//
// `process_soft_wrap_opportunity` handles both of these cases.
self.process_soft_wrap_opportunity();
// If the current portion of the unbreakable segment does not fit on the current line
// we need to put it on a new line *before* actually triggering the hard line break.
if !self.unbreakable_segment_fits_on_line() {
self.process_line_break(false /* forced_line_break */);
}
// Defer the actual line break until we've cleared all ending inline boxes.
self.linebreak_before_new_content = true;
@ -1371,6 +1368,20 @@ impl<'a, 'b> InlineFormattingContextState<'a, 'b> {
self.finish_current_line_and_reset(forced_line_break);
}
pub(super) fn unbreakable_segment_fits_on_line(&mut self) -> bool {
let potential_line_size = LogicalVec2 {
inline: self.current_line.inline_position + self.current_line_segment.inline_size -
self.current_line_segment.trailing_whitespace_size,
block: self
.current_line_max_block_size_including_nested_containers()
.max(&self.current_line_segment.max_block_size)
.resolve()
.into(),
};
!self.new_potential_line_size_causes_line_break(&potential_line_size)
}
/// Process a soft wrap opportunity. This will either commit the current unbreakble
/// segment to the current line, if it fits within the containing block and float
/// placement boundaries, or do a line break and then commit the segment.
@ -1633,7 +1644,6 @@ impl InlineFormattingContext {
linebreak_before_new_content: false,
deferred_br_clear: Clear::None,
have_deferred_soft_wrap_opportunity: false,
prevent_soft_wrap_opportunity_before_next_atomic: false,
had_inflow_content: false,
white_space_collapse: style_text.white_space_collapse,
text_wrap_mode: style_text.text_wrap_mode,
@ -1662,8 +1672,13 @@ impl InlineFormattingContext {
},
InlineItem::EndInlineBox => ifc.finish_inline_box(),
InlineItem::TextRun(run) => run.layout_into_line_items(&mut ifc),
InlineItem::Atomic(atomic_formatting_context) => {
atomic_formatting_context.layout_into_line_items(layout_context, &mut ifc);
InlineItem::Atomic(atomic_formatting_context, offset_in_text) => {
atomic_formatting_context.layout_into_line_items(
layout_context,
self,
&mut ifc,
*offset_in_text,
);
},
InlineItem::OutOfFlowAbsolutelyPositionedBox(positioned_box) => {
ifc.push_line_item_to_unbreakable_segment(LineItem::AbsolutelyPositioned(
@ -1694,6 +1709,20 @@ impl InlineFormattingContext {
baselines: ifc.baselines,
}
}
fn next_character_prevents_soft_wrap_opportunity(&self, index: usize) -> bool {
let Some(character) = self.text_content[index..].chars().skip(1).next() else {
return false;
};
char_prevents_soft_wrap_opportunity_when_before_or_after_atomic(character)
}
fn previous_character_prevents_soft_wrap_opportunity(&self, index: usize) -> bool {
let Some(character) = self.text_content[0..index].chars().rev().next() else {
return false;
};
char_prevents_soft_wrap_opportunity_when_before_or_after_atomic(character)
}
}
impl InlineContainerState {
@ -1894,10 +1923,12 @@ impl IndependentFormattingContext {
fn layout_into_line_items(
&mut self,
layout_context: &LayoutContext,
ifc: &mut InlineFormattingContextState,
inline_formatting_context: &InlineFormattingContext,
inline_formatting_context_state: &mut InlineFormattingContextState,
offset_in_text: usize,
) {
let style = self.style();
let pbm = style.padding_border_margin(ifc.containing_block);
let pbm = style.padding_border_margin(inline_formatting_context_state.containing_block);
let margin = pbm.margin.auto_is(Au::zero);
let pbm_sums = pbm.padding + pbm.border + margin;
let mut child_positioning_context = None;
@ -1906,7 +1937,7 @@ impl IndependentFormattingContext {
let fragment = match self {
IndependentFormattingContext::Replaced(replaced) => {
let size = replaced.contents.used_size_as_if_inline_element(
ifc.containing_block,
inline_formatting_context_state.containing_block,
&replaced.style,
None,
&pbm,
@ -1932,18 +1963,20 @@ impl IndependentFormattingContext {
IndependentFormattingContext::NonReplaced(non_replaced) => {
let box_size = non_replaced
.style
.content_box_size(ifc.containing_block, &pbm);
.content_box_size(inline_formatting_context_state.containing_block, &pbm);
let max_box_size = non_replaced
.style
.content_max_box_size(ifc.containing_block, &pbm);
.content_max_box_size(inline_formatting_context_state.containing_block, &pbm);
let min_box_size = non_replaced
.style
.content_min_box_size(ifc.containing_block, &pbm)
.content_min_box_size(inline_formatting_context_state.containing_block, &pbm)
.auto_is(Length::zero);
// https://drafts.csswg.org/css2/visudet.html#inlineblock-width
let tentative_inline_size = box_size.inline.auto_is(|| {
let available_size = ifc.containing_block.inline_size - pbm_sums.inline_sum();
let available_size =
inline_formatting_context_state.containing_block.inline_size -
pbm_sums.inline_sum();
non_replaced
.inline_content_sizes(layout_context)
.shrink_to_fit(available_size)
@ -1962,7 +1995,10 @@ impl IndependentFormattingContext {
style: &non_replaced.style,
};
assert_eq!(
ifc.containing_block.style.writing_mode,
inline_formatting_context_state
.containing_block
.style
.writing_mode,
containing_block_for_children.style.writing_mode,
"Mixed writing modes are not supported yet"
);
@ -1977,7 +2013,7 @@ impl IndependentFormattingContext {
layout_context,
child_positioning_context.as_mut().unwrap(),
&containing_block_for_children,
ifc.containing_block,
inline_formatting_context_state.containing_block,
);
let (inline_size, block_size) =
match independent_layout.content_inline_size_for_table {
@ -2021,12 +2057,11 @@ impl IndependentFormattingContext {
},
};
let soft_wrap_opportunity_prevented = mem::replace(
&mut ifc.prevent_soft_wrap_opportunity_before_next_atomic,
false,
);
if ifc.text_wrap_mode == TextWrapMode::Wrap && !soft_wrap_opportunity_prevented {
ifc.process_soft_wrap_opportunity();
if inline_formatting_context_state.text_wrap_mode == TextWrapMode::Wrap &&
!inline_formatting_context
.previous_character_prevents_soft_wrap_opportunity(offset_in_text)
{
inline_formatting_context_state.process_soft_wrap_opportunity();
}
let size = pbm_sums.sum() + fragment.content_rect.size;
@ -2035,15 +2070,18 @@ impl IndependentFormattingContext {
.map(|baseline| pbm_sums.block_start + baseline)
.unwrap_or(size.block);
let (block_sizes, baseline_offset_in_parent) =
self.get_block_sizes_and_baseline_offset(ifc, size.block.into(), baseline_offset);
ifc.update_unbreakable_segment_for_new_content(
let (block_sizes, baseline_offset_in_parent) = self.get_block_sizes_and_baseline_offset(
inline_formatting_context_state,
size.block.into(),
baseline_offset,
);
inline_formatting_context_state.update_unbreakable_segment_for_new_content(
&block_sizes,
size.inline.into(),
SegmentContentFlags::empty(),
);
ifc.push_line_item_to_unbreakable_segment(LineItem::Atomic(
ifc.current_inline_box_identifier(),
inline_formatting_context_state.push_line_item_to_unbreakable_segment(LineItem::Atomic(
inline_formatting_context_state.current_inline_box_identifier(),
AtomicLineItem {
fragment,
size,
@ -2053,8 +2091,12 @@ impl IndependentFormattingContext {
},
));
// Defer a soft wrap opportunity for when we next process text content.
ifc.have_deferred_soft_wrap_opportunity = true;
// If there's a soft wrap opportunity following this atomic, defer a soft wrap opportunity
// for when we next process text content.
if !inline_formatting_context.next_character_prevents_soft_wrap_opportunity(offset_in_text)
{
inline_formatting_context_state.have_deferred_soft_wrap_opportunity = true;
}
}
/// Picks either the first or the last baseline, depending on `baseline-source`.
@ -2345,12 +2387,25 @@ impl<'a> ContentSizesComputation<'a> {
}
}
},
InlineItem::Atomic(atomic) => {
InlineItem::Atomic(atomic, offset_in_text) => {
// TODO: need to handle TextWrapMode::Nowrap.
if !inline_formatting_context
.previous_character_prevents_soft_wrap_opportunity(*offset_in_text)
{
self.line_break_opportunity();
}
let outer = atomic.outer_inline_content_sizes(
self.layout_context,
self.containing_block_writing_mode,
);
if !inline_formatting_context
.next_character_prevents_soft_wrap_opportunity(*offset_in_text)
{
self.line_break_opportunity();
}
self.commit_pending_whitespace();
self.current_line += outer;
self.had_content_yet = true;
@ -2404,3 +2459,24 @@ impl<'a> ContentSizesComputation<'a> {
.traverse(inline_formatting_context)
}
}
/// Whether or not this character will rpevent a soft wrap opportunity when it
/// comes before or after an atomic inline element.
///
/// From <https://www.w3.org/TR/css-text-3/#line-break-details>:
///
/// > For Web-compatibility there is a soft wrap opportunity before and after each
/// > replaced element or other atomic inline, even when adjacent to a character that
/// > would normally suppress them, including U+00A0 NO-BREAK SPACE. However, with
/// > the exception of U+00A0 NO-BREAK SPACE, there must be no soft wrap opportunity
/// > between atomic inlines and adjacent characters belonging to the Unicode GL, WJ,
/// > or ZWJ line breaking classes.
fn char_prevents_soft_wrap_opportunity_when_before_or_after_atomic(character: char) -> bool {
if character == '\u{00A0}' {
return false;
}
let class = linebreak_property(character);
class == XI_LINE_BREAKING_CLASS_GL ||
class == XI_LINE_BREAKING_CLASS_WJ ||
class == XI_LINE_BREAKING_CLASS_ZWJ
}