servo/components/layout_2020/flow/inline.rs
Martin Robinson 4f4c2a5922
Remove rayon_croissant and clean up contains_floats (#29960)
Remove rayon_croissant and refactor the way that information about
floats in flows bubbles up. This simplifies the code a good deal and
lets us take advantage of some more optimized functions provided by
rayon. This removes 2 crates from the dependency tree.

In addition, this allows avoiding passing `contains_floats` up from
every box tree construction function. This makes things simpler, but
also opens up the possibility of passing more of these flags up in the
future (such as `contains_counters`).
2023-07-19 07:01:55 +00:00

1013 lines
40 KiB
Rust

/* 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 https://mozilla.org/MPL/2.0/. */
use crate::cell::ArcRefCell;
use crate::context::LayoutContext;
use crate::flow::float::{FloatBox, SequentialLayoutState};
use crate::flow::FlowLayout;
use crate::formatting_contexts::IndependentFormattingContext;
use crate::fragment_tree::{
AnonymousFragment, BaseFragmentInfo, BoxFragment, CollapsedBlockMargins, CollapsedMargin,
FontMetrics, Fragment, TextFragment,
};
use crate::geom::flow_relative::{Rect, Sides, Vec2};
use crate::positioned::{
relative_adjustement, AbsolutelyPositionedBox, HoistedAbsolutelyPositionedBox,
PositioningContext,
};
use crate::sizing::ContentSizes;
use crate::style_ext::{ComputedValuesExt, Display, DisplayGeneratingBox, DisplayOutside};
use crate::ContainingBlock;
use app_units::Au;
use atomic_refcell::AtomicRef;
use gfx::text::text_run::GlyphRun;
use servo_arc::Arc;
use style::computed_values::white_space::T as WhiteSpace;
use style::logical_geometry::WritingMode;
use style::properties::ComputedValues;
use style::values::computed::{Length, LengthPercentage, Percentage};
use style::values::specified::text::TextAlignKeyword;
use style::values::specified::text::TextDecorationLine;
use style::Zero;
use webrender_api::FontInstanceKey;
#[derive(Debug, Serialize)]
pub(crate) struct InlineFormattingContext {
pub(super) inline_level_boxes: Vec<ArcRefCell<InlineLevelBox>>,
pub(super) text_decoration_line: TextDecorationLine,
// Whether this IFC contains the 1st formatted line of an element
// https://www.w3.org/TR/css-pseudo-4/#first-formatted-line
pub(super) has_first_formatted_line: bool,
pub(super) contains_floats: bool,
}
#[derive(Debug, Serialize)]
pub(crate) enum InlineLevelBox {
InlineBox(InlineBox),
TextRun(TextRun),
OutOfFlowAbsolutelyPositionedBox(ArcRefCell<AbsolutelyPositionedBox>),
OutOfFlowFloatBox(FloatBox),
Atomic(IndependentFormattingContext),
}
#[derive(Debug, Serialize)]
pub(crate) struct InlineBox {
pub base_fragment_info: BaseFragmentInfo,
#[serde(skip_serializing)]
pub style: Arc<ComputedValues>,
pub first_fragment: bool,
pub last_fragment: bool,
pub children: Vec<ArcRefCell<InlineLevelBox>>,
}
/// https://www.w3.org/TR/css-display-3/#css-text-run
#[derive(Debug, Serialize)]
pub(crate) struct TextRun {
pub base_fragment_info: BaseFragmentInfo,
#[serde(skip_serializing)]
pub parent_style: Arc<ComputedValues>,
pub text: String,
}
struct InlineNestingLevelState<'box_tree> {
remaining_boxes: InlineBoxChildIter<'box_tree>,
fragments_so_far: Vec<Fragment>,
inline_start: Length,
max_block_size_of_fragments_so_far: Length,
positioning_context: Option<PositioningContext>,
white_space: WhiteSpace,
/// Indicates whether this nesting level have text decorations in effect.
/// From https://drafts.csswg.org/css-text-decor/#line-decoration
// "When specified on or propagated to a block container that establishes
// an IFC..."
text_decoration_line: TextDecorationLine,
}
struct PartialInlineBoxFragment<'box_tree> {
base_fragment_info: BaseFragmentInfo,
style: Arc<ComputedValues>,
start_corner: Vec2<Length>,
padding: Sides<Length>,
border: Sides<Length>,
margin: Sides<Length>,
last_box_tree_fragment: bool,
parent_nesting_level: InlineNestingLevelState<'box_tree>,
}
struct InlineFormattingContextState<'box_tree, 'a, 'b> {
positioning_context: &'a mut PositioningContext,
containing_block: &'b ContainingBlock<'b>,
lines: Lines,
inline_position: Length,
partial_inline_boxes_stack: Vec<PartialInlineBoxFragment<'box_tree>>,
current_nesting_level: InlineNestingLevelState<'box_tree>,
sequential_layout_state: Option<&'a mut SequentialLayoutState>,
}
impl<'box_tree, 'a, 'b> InlineFormattingContextState<'box_tree, 'a, 'b> {
fn push_hoisted_box_to_positioning_context(
&mut self,
hoisted_box: HoistedAbsolutelyPositionedBox,
) {
if let Some(context) = self.current_nesting_level.positioning_context.as_mut() {
context.push(hoisted_box);
return;
}
for nesting_level in self.partial_inline_boxes_stack.iter_mut().rev() {
if let Some(context) = nesting_level
.parent_nesting_level
.positioning_context
.as_mut()
{
context.push(hoisted_box);
return;
}
}
self.positioning_context.push(hoisted_box);
}
/// Finish layout of all the partial inline boxes in the current line,
/// finish current line and start a new one.
fn finish_line_and_reset(&mut self, layout_context: &LayoutContext) {
self.current_nesting_level.inline_start = Length::zero();
let mut nesting_level = &mut self.current_nesting_level;
for partial in self.partial_inline_boxes_stack.iter_mut().rev() {
partial.finish_layout(
layout_context,
nesting_level,
&mut self.inline_position,
true,
);
partial.start_corner.inline = Length::zero();
partial.padding.inline_start = Length::zero();
partial.border.inline_start = Length::zero();
partial.margin.inline_start = Length::zero();
partial.parent_nesting_level.inline_start = Length::zero();
nesting_level = &mut partial.parent_nesting_level;
}
self.lines.finish_line(
nesting_level,
self.containing_block,
self.sequential_layout_state.as_mut().map(|c| &mut **c),
self.inline_position,
);
self.inline_position = Length::zero();
}
}
struct Lines {
// One anonymous fragment per line
fragments: Vec<Fragment>,
next_line_block_position: Length,
}
impl InlineFormattingContext {
pub(super) fn new(
text_decoration_line: TextDecorationLine,
has_first_formatted_line: bool,
) -> InlineFormattingContext {
InlineFormattingContext {
inline_level_boxes: Default::default(),
text_decoration_line,
has_first_formatted_line,
contains_floats: false,
}
}
// This works on an already-constructed `InlineFormattingContext`,
// Which would have to change if/when
// `BlockContainer::construct` parallelize their construction.
pub(super) fn inline_content_sizes(
&self,
layout_context: &LayoutContext,
containing_block_writing_mode: WritingMode,
) -> ContentSizes {
struct Computation<'a> {
layout_context: &'a LayoutContext<'a>,
containing_block_writing_mode: WritingMode,
paragraph: ContentSizes,
current_line: ContentSizes,
current_line_percentages: Percentage,
}
impl Computation<'_> {
fn traverse(&mut self, inline_level_boxes: &[ArcRefCell<InlineLevelBox>]) {
for inline_level_box in inline_level_boxes {
match &mut *inline_level_box.borrow_mut() {
InlineLevelBox::InlineBox(inline_box) => {
let padding =
inline_box.style.padding(self.containing_block_writing_mode);
let border = inline_box
.style
.border_width(self.containing_block_writing_mode);
let margin =
inline_box.style.margin(self.containing_block_writing_mode);
macro_rules! add {
($condition: ident, $side: ident) => {
if inline_box.$condition {
self.add_lengthpercentage(padding.$side);
self.add_length(border.$side);
if let Some(lp) = margin.$side.non_auto() {
self.add_lengthpercentage(lp)
}
}
};
}
add!(first_fragment, inline_start);
self.traverse(&inline_box.children);
add!(last_fragment, inline_end);
},
InlineLevelBox::TextRun(text_run) => {
let BreakAndShapeResult {
runs,
break_at_start,
..
} = text_run.break_and_shape(self.layout_context);
if break_at_start {
self.line_break_opportunity()
}
for run in &runs {
let advance = Length::from(run.glyph_store.total_advance());
if run.glyph_store.is_whitespace() {
self.line_break_opportunity()
} else {
self.current_line.min_content += advance
}
self.current_line.max_content += advance
}
},
InlineLevelBox::Atomic(atomic) => {
let (outer, pc) = atomic.outer_inline_content_sizes_and_percentages(
self.layout_context,
self.containing_block_writing_mode,
);
self.current_line.min_content += outer.min_content;
self.current_line.max_content += outer.max_content;
self.current_line_percentages += pc;
},
InlineLevelBox::OutOfFlowFloatBox(_) |
InlineLevelBox::OutOfFlowAbsolutelyPositionedBox(_) => {},
}
}
}
fn add_lengthpercentage(&mut self, lp: &LengthPercentage) {
if let Some(l) = lp.to_length() {
self.add_length(l);
}
if let Some(p) = lp.to_percentage() {
self.current_line_percentages += p;
}
}
fn add_length(&mut self, l: Length) {
self.current_line.min_content += l;
self.current_line.max_content += l;
}
fn line_break_opportunity(&mut self) {
self.paragraph
.min_content
.max_assign(take(&mut self.current_line.min_content));
}
fn forced_line_break(&mut self) {
self.line_break_opportunity();
self.current_line
.adjust_for_pbm_percentages(take(&mut self.current_line_percentages));
self.paragraph
.max_content
.max_assign(take(&mut self.current_line.max_content));
}
}
fn take<T: Zero>(x: &mut T) -> T {
std::mem::replace(x, T::zero())
}
let mut computation = Computation {
layout_context,
containing_block_writing_mode,
paragraph: ContentSizes::zero(),
current_line: ContentSizes::zero(),
current_line_percentages: Percentage::zero(),
};
computation.traverse(&self.inline_level_boxes);
computation.forced_line_break();
computation.paragraph
}
pub(super) fn layout(
&self,
layout_context: &LayoutContext,
positioning_context: &mut PositioningContext,
containing_block: &ContainingBlock,
sequential_layout_state: Option<&mut SequentialLayoutState>,
) -> FlowLayout {
let mut ifc = InlineFormattingContextState {
positioning_context,
containing_block,
partial_inline_boxes_stack: Vec::new(),
lines: Lines {
fragments: Vec::new(),
next_line_block_position: Length::zero(),
},
inline_position: if self.has_first_formatted_line {
containing_block
.style
.get_inherited_text()
.text_indent
.to_used_value(containing_block.inline_size.into())
.into()
} else {
Length::zero()
},
current_nesting_level: InlineNestingLevelState {
remaining_boxes: InlineBoxChildIter::from_formatting_context(self),
fragments_so_far: Vec::with_capacity(self.inline_level_boxes.len()),
inline_start: Length::zero(),
max_block_size_of_fragments_so_far: Length::zero(),
positioning_context: None,
white_space: containing_block.style.clone_inherited_text().white_space,
text_decoration_line: self.text_decoration_line,
},
sequential_layout_state,
};
// FIXME(pcwalton): This assumes that margins never collapse through inline formatting
// contexts (i.e. that inline formatting contexts are never empty). Is that right?
if let Some(ref mut sequential_layout_state) = ifc.sequential_layout_state {
sequential_layout_state.collapse_margins();
}
loop {
if let Some(child) = ifc.current_nesting_level.remaining_boxes.next() {
match &mut *child.borrow_mut() {
InlineLevelBox::InlineBox(inline) => {
let partial = inline.start_layout(child.clone(), &mut ifc);
ifc.partial_inline_boxes_stack.push(partial)
},
InlineLevelBox::TextRun(run) => run.layout(layout_context, &mut ifc),
InlineLevelBox::Atomic(a) => layout_atomic(layout_context, &mut ifc, a),
InlineLevelBox::OutOfFlowAbsolutelyPositionedBox(box_) => {
let style = AtomicRef::map(box_.borrow(), |box_| box_.context.style());
let initial_start_corner =
match Display::from(style.get_box().original_display) {
Display::GeneratingBox(DisplayGeneratingBox::OutsideInside {
outside,
inside: _,
}) => Vec2 {
inline: match outside {
DisplayOutside::Inline => ifc.inline_position,
DisplayOutside::Block => Length::zero(),
},
block: ifc.lines.next_line_block_position,
},
Display::Contents => {
panic!("display:contents does not generate an abspos box")
},
Display::None => {
panic!("display:none does not generate an abspos box")
},
};
let hoisted_box = AbsolutelyPositionedBox::to_hoisted(
box_.clone(),
initial_start_corner,
ifc.containing_block,
);
let hoisted_fragment = hoisted_box.fragment.clone();
ifc.push_hoisted_box_to_positioning_context(hoisted_box);
ifc.current_nesting_level
.fragments_so_far
.push(Fragment::AbsoluteOrFixedPositioned(hoisted_fragment));
},
InlineLevelBox::OutOfFlowFloatBox(float_box) => {
let mut box_fragment = float_box.layout(
layout_context,
ifc.positioning_context,
containing_block,
);
let state = ifc
.sequential_layout_state
.as_mut()
.expect("Tried to lay out a float with no sequential placement state!");
let block_offset_from_containining_block_top = state
.current_block_position_including_margins() -
state.current_containing_block_offset();
state.place_float_fragment(
&mut box_fragment,
CollapsedMargin::zero(),
block_offset_from_containining_block_top,
);
ifc.current_nesting_level
.fragments_so_far
.push(Fragment::Float(box_fragment));
},
}
} else
// Reached the end of ifc.remaining_boxes
if let Some(mut partial) = ifc.partial_inline_boxes_stack.pop() {
partial.finish_layout(
layout_context,
&mut ifc.current_nesting_level,
&mut ifc.inline_position,
false,
);
ifc.current_nesting_level = partial.parent_nesting_level
} else {
ifc.lines.finish_line(
&mut ifc.current_nesting_level,
containing_block,
ifc.sequential_layout_state,
ifc.inline_position,
);
return FlowLayout {
fragments: ifc.lines.fragments,
content_block_size: ifc.lines.next_line_block_position,
collapsible_margins_in_children: CollapsedBlockMargins::zero(),
};
}
}
}
}
impl Lines {
fn finish_line(
&mut self,
top_nesting_level: &mut InlineNestingLevelState,
containing_block: &ContainingBlock,
mut sequential_layout_state: Option<&mut SequentialLayoutState>,
line_content_inline_size: Length,
) {
let mut line_contents = std::mem::take(&mut top_nesting_level.fragments_so_far);
let line_block_size = std::mem::replace(
&mut top_nesting_level.max_block_size_of_fragments_so_far,
Length::zero(),
);
enum TextAlign {
Start,
Center,
End,
}
let line_left_is_inline_start = containing_block
.style
.writing_mode
.line_left_is_inline_start();
let text_align = match containing_block.style.clone_text_align() {
TextAlignKeyword::Start => TextAlign::Start,
TextAlignKeyword::Center => TextAlign::Center,
TextAlignKeyword::End => TextAlign::End,
TextAlignKeyword::Left => {
if line_left_is_inline_start {
TextAlign::Start
} else {
TextAlign::End
}
},
TextAlignKeyword::Right => {
if line_left_is_inline_start {
TextAlign::End
} else {
TextAlign::Start
}
},
TextAlignKeyword::Justify => {
// TODO: Add support for justfied text.
TextAlign::Start
},
TextAlignKeyword::ServoCenter |
TextAlignKeyword::ServoLeft |
TextAlignKeyword::ServoRight => {
// TODO: Implement these modes which seem to be used by quirks mode.
TextAlign::Start
},
};
let move_by = match text_align {
TextAlign::Start => Length::zero(),
TextAlign::Center => (containing_block.inline_size - line_content_inline_size) / 2.,
TextAlign::End => containing_block.inline_size - line_content_inline_size,
};
if move_by > Length::zero() {
for fragment in &mut line_contents {
fragment.offset_inline(&move_by);
}
}
let start_corner = Vec2 {
inline: Length::zero(),
block: self.next_line_block_position,
};
let size = Vec2 {
inline: containing_block.inline_size,
block: line_block_size,
};
self.next_line_block_position += size.block;
if let Some(ref mut sequential_layout_state) = sequential_layout_state {
sequential_layout_state.advance_block_position(size.block);
}
self.fragments
.push(Fragment::Anonymous(AnonymousFragment::new(
Rect { start_corner, size },
line_contents,
containing_block.style.writing_mode,
)))
}
}
impl InlineBox {
fn start_layout<'box_tree>(
&self,
this_inline_level_box: ArcRefCell<InlineLevelBox>,
ifc: &mut InlineFormattingContextState<'box_tree, '_, '_>,
) -> PartialInlineBoxFragment<'box_tree> {
let style = self.style.clone();
let pbm = style.padding_border_margin(&ifc.containing_block);
let mut padding = pbm.padding;
let mut border = pbm.border;
let mut margin = pbm.margin.auto_is(Length::zero);
if self.first_fragment {
ifc.inline_position += padding.inline_start + border.inline_start + margin.inline_start;
} else {
padding.inline_start = Length::zero();
border.inline_start = Length::zero();
margin.inline_start = Length::zero();
}
let mut start_corner = Vec2 {
block: Length::zero(),
inline: ifc.inline_position - ifc.current_nesting_level.inline_start,
};
if style.clone_position().is_relative() {
start_corner += &relative_adjustement(&style, ifc.containing_block)
}
let positioning_context = PositioningContext::new_for_style(&style);
let white_space = style.clone_inherited_text().white_space;
let text_decoration_line =
ifc.current_nesting_level.text_decoration_line | style.clone_text_decoration_line();
PartialInlineBoxFragment {
base_fragment_info: self.base_fragment_info,
style,
start_corner,
padding,
border,
margin,
last_box_tree_fragment: self.last_fragment,
parent_nesting_level: std::mem::replace(
&mut ifc.current_nesting_level,
InlineNestingLevelState {
remaining_boxes: InlineBoxChildIter::from_inline_level_box(
this_inline_level_box,
),
fragments_so_far: Vec::with_capacity(self.children.len()),
inline_start: ifc.inline_position,
max_block_size_of_fragments_so_far: Length::zero(),
positioning_context,
white_space,
text_decoration_line: text_decoration_line,
},
),
}
}
}
impl<'box_tree> PartialInlineBoxFragment<'box_tree> {
fn finish_layout(
&mut self,
layout_context: &LayoutContext,
nesting_level: &mut InlineNestingLevelState,
inline_position: &mut Length,
at_line_break: bool,
) {
let content_rect = Rect {
size: Vec2 {
inline: *inline_position - self.start_corner.inline,
block: nesting_level.max_block_size_of_fragments_so_far,
},
start_corner: self.start_corner.clone(),
};
let mut fragment = BoxFragment::new(
self.base_fragment_info,
self.style.clone(),
std::mem::take(&mut nesting_level.fragments_so_far),
content_rect,
self.padding.clone(),
self.border.clone(),
self.margin.clone(),
None,
CollapsedBlockMargins::zero(),
);
let last_fragment = self.last_box_tree_fragment && !at_line_break;
if last_fragment {
*inline_position += fragment.padding.inline_end +
fragment.border.inline_end +
fragment.margin.inline_end;
} else {
fragment.padding.inline_end = Length::zero();
fragment.border.inline_end = Length::zero();
fragment.margin.inline_end = Length::zero();
}
self.parent_nesting_level
.max_block_size_of_fragments_so_far
.max_assign(fragment.content_rect.size.block);
if let Some(context) = nesting_level.positioning_context.as_mut() {
context.layout_collected_children(layout_context, &mut fragment);
}
self.parent_nesting_level
.fragments_so_far
.push(Fragment::Box(fragment));
}
}
fn layout_atomic(
layout_context: &LayoutContext,
ifc: &mut InlineFormattingContextState,
atomic: &mut IndependentFormattingContext,
) {
let style = atomic.style();
let pbm = style.padding_border_margin(&ifc.containing_block);
let margin = pbm.margin.auto_is(Length::zero);
let pbm_sums = &(&pbm.padding + &pbm.border) + &margin;
let position = style.clone_position();
let mut child_positioning_context = None;
// We need to know the inline size of the atomic before deciding whether to do the line break.
let mut fragment = match atomic {
IndependentFormattingContext::Replaced(replaced) => {
let size = replaced.contents.used_size_as_if_inline_element(
ifc.containing_block,
&replaced.style,
None,
&pbm,
);
let fragments = replaced
.contents
.make_fragments(&replaced.style, size.clone());
let content_rect = Rect {
start_corner: Vec2::zero(),
size,
};
BoxFragment::new(
replaced.base_fragment_info,
replaced.style.clone(),
fragments,
content_rect,
pbm.padding,
pbm.border,
margin,
None,
CollapsedBlockMargins::zero(),
)
},
IndependentFormattingContext::NonReplaced(non_replaced) => {
let box_size = non_replaced
.style
.content_box_size(&ifc.containing_block, &pbm);
let max_box_size = non_replaced
.style
.content_max_box_size(&ifc.containing_block, &pbm);
let min_box_size = non_replaced
.style
.content_min_box_size(&ifc.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();
non_replaced
.inline_content_sizes(layout_context)
.shrink_to_fit(available_size)
});
// https://drafts.csswg.org/css2/visudet.html#min-max-widths
// In this case “applying the rules above again” with a non-auto inline-size
// always results in that size.
let inline_size = tentative_inline_size
.clamp_between_extremums(min_box_size.inline, max_box_size.inline);
let containing_block_for_children = ContainingBlock {
inline_size,
block_size: box_size.block,
style: &non_replaced.style,
};
assert_eq!(
ifc.containing_block.style.writing_mode,
containing_block_for_children.style.writing_mode,
"Mixed writing modes are not supported yet"
);
let collects_for_nearest_positioned_ancestor = ifc
.positioning_context
.collects_for_nearest_positioned_ancestor();
child_positioning_context = Some(PositioningContext::new_for_subtree(
collects_for_nearest_positioned_ancestor,
));
let independent_layout = non_replaced.layout(
layout_context,
child_positioning_context.as_mut().unwrap(),
&containing_block_for_children,
);
// https://drafts.csswg.org/css2/visudet.html#block-root-margin
let tentative_block_size = box_size
.block
.auto_is(|| independent_layout.content_block_size);
// https://drafts.csswg.org/css2/visudet.html#min-max-heights
// In this case “applying the rules above again” with a non-auto block-size
// always results in that size.
let block_size = tentative_block_size
.clamp_between_extremums(min_box_size.block, max_box_size.block);
let content_rect = Rect {
start_corner: Vec2::zero(),
size: Vec2 {
block: block_size,
inline: inline_size,
},
};
BoxFragment::new(
non_replaced.base_fragment_info,
non_replaced.style.clone(),
independent_layout.fragments,
content_rect,
pbm.padding,
pbm.border,
margin,
None,
CollapsedBlockMargins::zero(),
)
},
};
if fragment.content_rect.size.inline + pbm_sums.inline_sum() >
ifc.containing_block.inline_size - ifc.inline_position &&
ifc.current_nesting_level.white_space.allow_wrap() &&
ifc.current_nesting_level.fragments_so_far.len() != 0
{
ifc.finish_line_and_reset(layout_context);
}
ifc.inline_position += pbm_sums.inline_start;
let mut start_corner = Vec2 {
block: pbm_sums.block_start,
inline: ifc.inline_position - ifc.current_nesting_level.inline_start,
};
if position.is_relative() {
start_corner += &relative_adjustement(atomic.style(), ifc.containing_block)
}
if let Some(mut child_positioning_context) = child_positioning_context.take() {
child_positioning_context
.adjust_static_position_of_hoisted_fragments_with_offset(&start_corner);
ifc.positioning_context.append(child_positioning_context);
}
fragment.content_rect.start_corner = start_corner;
ifc.inline_position += pbm_sums.inline_end + fragment.content_rect.size.inline;
ifc.current_nesting_level
.max_block_size_of_fragments_so_far
.max_assign(pbm_sums.block_sum() + fragment.content_rect.size.block);
ifc.current_nesting_level
.fragments_so_far
.push(Fragment::Box(fragment));
}
struct BreakAndShapeResult {
font_metrics: FontMetrics,
font_key: FontInstanceKey,
runs: Vec<GlyphRun>,
break_at_start: bool,
}
impl TextRun {
fn break_and_shape(&self, layout_context: &LayoutContext) -> BreakAndShapeResult {
use gfx::font::ShapingFlags;
use style::computed_values::text_rendering::T as TextRendering;
use style::computed_values::word_break::T as WordBreak;
let font_style = self.parent_style.clone_font();
let inherited_text_style = self.parent_style.get_inherited_text();
let letter_spacing = if inherited_text_style.letter_spacing.0.px() != 0. {
Some(app_units::Au::from(inherited_text_style.letter_spacing.0))
} else {
None
};
let mut flags = ShapingFlags::empty();
if letter_spacing.is_some() {
flags.insert(ShapingFlags::IGNORE_LIGATURES_SHAPING_FLAG);
}
if inherited_text_style.text_rendering == TextRendering::Optimizespeed {
flags.insert(ShapingFlags::IGNORE_LIGATURES_SHAPING_FLAG);
flags.insert(ShapingFlags::DISABLE_KERNING_SHAPING_FLAG)
}
if inherited_text_style.word_break == WordBreak::KeepAll {
flags.insert(ShapingFlags::KEEP_ALL_FLAG);
}
crate::context::with_thread_local_font_context(layout_context, |font_context| {
let font_group = font_context.font_group(font_style);
let font = font_group
.borrow_mut()
.first(font_context)
.expect("could not find font");
let mut font = font.borrow_mut();
let word_spacing = &inherited_text_style.word_spacing;
let word_spacing = word_spacing
.to_length()
.map(|l| l.into())
.unwrap_or_else(|| {
let space_width = font
.glyph_index(' ')
.map(|glyph_id| font.glyph_h_advance(glyph_id))
.unwrap_or(gfx::font::LAST_RESORT_GLYPH_ADVANCE);
word_spacing.to_used_value(Au::from_f64_px(space_width))
});
let shaping_options = gfx::font::ShapingOptions {
letter_spacing,
word_spacing,
script: unicode_script::Script::Common,
flags,
};
let (runs, break_at_start) = gfx::text::text_run::TextRun::break_and_shape(
&mut font,
&self.text,
&shaping_options,
&mut None,
);
BreakAndShapeResult {
font_metrics: (&font.metrics).into(),
font_key: font.font_key,
runs,
break_at_start,
}
})
}
fn layout(&self, layout_context: &LayoutContext, ifc: &mut InlineFormattingContextState) {
use style::values::generics::text::LineHeight;
let BreakAndShapeResult {
font_metrics,
font_key,
runs,
break_at_start: _,
} = self.break_and_shape(layout_context);
let font_size = self.parent_style.get_font().font_size.size.0;
let mut runs = runs.iter();
loop {
let mut glyphs = vec![];
let mut advance_width = Length::zero();
let mut last_break_opportunity = None;
let mut force_line_break = false;
// Fit as many glyphs within a single line as possible.
loop {
let next = runs.next();
// If there are no more text runs we still need to check if the last
// run was a forced line break
if next
.as_ref()
.map_or(true, |run| run.glyph_store.is_whitespace())
{
// If this run exceeds the bounds of the containing block, then
// we need to attempt to break the line.
if advance_width > ifc.containing_block.inline_size - ifc.inline_position {
// Reset the text run iterator to the last whitespace if possible,
// to attempt to re-layout the most recent glyphs on a new line.
if let Some((len, width, iter)) = last_break_opportunity.take() {
glyphs.truncate(len);
advance_width = width;
runs = iter;
}
break;
}
}
if let Some(run) = next {
if run.glyph_store.is_whitespace() {
last_break_opportunity = Some((glyphs.len(), advance_width, runs.clone()));
// If this whitespace ends with a newline, we need to check if
// it's meaningful within the current style. If so, we force
// a line break immediately.
let last_byte = self.text.as_bytes().get(run.range.end().to_usize() - 1);
if last_byte == Some(&b'\n') &&
self.parent_style
.get_inherited_text()
.white_space
.preserve_newlines()
{
force_line_break = true;
break;
}
}
glyphs.push(run.glyph_store.clone());
advance_width += Length::from(run.glyph_store.total_advance());
} else {
// No more runs, so we can end the line.
break;
}
}
let line_height = match self.parent_style.get_inherited_text().line_height {
LineHeight::Normal => font_metrics.line_gap,
LineHeight::Number(n) => font_size * n.0,
LineHeight::Length(l) => l.0,
};
let rect = Rect {
start_corner: Vec2 {
block: Length::zero(),
inline: ifc.inline_position - ifc.current_nesting_level.inline_start,
},
size: Vec2 {
block: line_height,
inline: advance_width,
},
};
ifc.inline_position += advance_width;
ifc.current_nesting_level
.max_block_size_of_fragments_so_far
.max_assign(line_height);
ifc.current_nesting_level
.fragments_so_far
.push(Fragment::Text(TextFragment {
base: self.base_fragment_info.into(),
parent_style: self.parent_style.clone(),
rect,
font_metrics,
font_key,
glyphs,
text_decoration_line: ifc.current_nesting_level.text_decoration_line,
}));
// If this line is being broken because of a trailing newline, we can't ignore it.
if runs.as_slice().is_empty() && !force_line_break {
break;
} else {
ifc.finish_line_and_reset(layout_context);
}
}
}
}
enum InlineBoxChildIter<'box_tree> {
InlineFormattingContext(std::slice::Iter<'box_tree, ArcRefCell<InlineLevelBox>>),
InlineBox {
inline_level_box: ArcRefCell<InlineLevelBox>,
child_index: usize,
},
}
impl<'box_tree> InlineBoxChildIter<'box_tree> {
fn from_formatting_context(
inline_formatting_context: &'box_tree InlineFormattingContext,
) -> InlineBoxChildIter<'box_tree> {
InlineBoxChildIter::InlineFormattingContext(
inline_formatting_context.inline_level_boxes.iter(),
)
}
fn from_inline_level_box(
inline_level_box: ArcRefCell<InlineLevelBox>,
) -> InlineBoxChildIter<'box_tree> {
InlineBoxChildIter::InlineBox {
inline_level_box,
child_index: 0,
}
}
}
impl<'box_tree> Iterator for InlineBoxChildIter<'box_tree> {
type Item = ArcRefCell<InlineLevelBox>;
fn next(&mut self) -> Option<ArcRefCell<InlineLevelBox>> {
match *self {
InlineBoxChildIter::InlineFormattingContext(ref mut iter) => iter.next().cloned(),
InlineBoxChildIter::InlineBox {
ref inline_level_box,
ref mut child_index,
} => match *inline_level_box.borrow() {
InlineLevelBox::InlineBox(ref inline_box) => {
if *child_index >= inline_box.children.len() {
return None;
}
let kid = inline_box.children[*child_index].clone();
*child_index += 1;
Some(kid)
},
_ => unreachable!(),
},
}
}
}