mirror of
https://github.com/servo/servo.git
synced 2025-06-06 16:45:39 +00:00
08f008a011
… and converting them to flow-relative geometric values. These values are almost always used to size and position a fragment within its containing block, so using the mode of the containing block seems more correct. Note that the `writing-mode` and `direction` properties are disabled in Servo at the moment, so this PR by itself should have no effect: the writing mode of an element is always the same of that of its containing block since they’re both horizontal rtl.
729 lines
28 KiB
Rust
729 lines
28 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::dom_traversal::{Contents, NodeAndStyleInfo, NodeExt};
|
||
use crate::formatting_contexts::IndependentFormattingContext;
|
||
use crate::fragments::{BoxFragment, CollapsedBlockMargins, Fragment};
|
||
use crate::geom::flow_relative::{Rect, Sides, Vec2};
|
||
use crate::geom::{LengthOrAuto, LengthPercentageOrAuto};
|
||
use crate::sizing::ContentSizesRequest;
|
||
use crate::style_ext::{ComputedValuesExt, DisplayInside};
|
||
use crate::{ContainingBlock, DefiniteContainingBlock};
|
||
use rayon::iter::{IntoParallelRefMutIterator, ParallelExtend};
|
||
use rayon_croissant::ParallelIteratorExt;
|
||
use style::computed_values::position::T as Position;
|
||
use style::properties::ComputedValues;
|
||
use style::values::computed::{Length, LengthPercentage};
|
||
use style::values::specified::text::TextDecorationLine;
|
||
use style::Zero;
|
||
|
||
#[derive(Debug, Serialize)]
|
||
pub(crate) struct AbsolutelyPositionedBox {
|
||
pub contents: IndependentFormattingContext,
|
||
}
|
||
|
||
pub(crate) struct PositioningContext {
|
||
for_nearest_positioned_ancestor: Option<Vec<HoistedAbsolutelyPositionedBox>>,
|
||
|
||
// For nearest `containing block for all descendants` as defined by the CSS transforms
|
||
// spec.
|
||
// https://www.w3.org/TR/css-transforms-1/#containing-block-for-all-descendants
|
||
for_nearest_containing_block_for_all_descendants: Vec<HoistedAbsolutelyPositionedBox>,
|
||
}
|
||
|
||
pub(crate) struct HoistedAbsolutelyPositionedBox {
|
||
absolutely_positioned_box: ArcRefCell<AbsolutelyPositionedBox>,
|
||
|
||
/// The rank of the child from which this absolutely positioned fragment
|
||
/// came from, when doing the layout of a block container. Used to compute
|
||
/// static positions when going up the tree.
|
||
pub(crate) tree_rank: usize,
|
||
|
||
box_offsets: Vec2<AbsoluteBoxOffsets>,
|
||
|
||
/// A reference to a Fragment which is shared between this `HoistedAbsolutelyPositionedBox`
|
||
/// and its placeholder `AbsoluteOrFixedPositionedFragment` in the original tree position.
|
||
/// This will be used later in order to paint this hoisted box in tree order.
|
||
pub fragment: ArcRefCell<Option<ArcRefCell<Fragment>>>,
|
||
}
|
||
|
||
#[derive(Clone, Debug)]
|
||
pub(crate) enum AbsoluteBoxOffsets {
|
||
StaticStart {
|
||
start: Length,
|
||
},
|
||
Start {
|
||
start: LengthPercentage,
|
||
},
|
||
End {
|
||
end: LengthPercentage,
|
||
},
|
||
Both {
|
||
start: LengthPercentage,
|
||
end: LengthPercentage,
|
||
},
|
||
}
|
||
|
||
impl AbsolutelyPositionedBox {
|
||
pub fn construct<'dom>(
|
||
context: &LayoutContext,
|
||
node_info: &NodeAndStyleInfo<impl NodeExt<'dom>>,
|
||
display_inside: DisplayInside,
|
||
contents: Contents,
|
||
) -> Self {
|
||
// "Shrink-to-fit" in https://drafts.csswg.org/css2/visudet.html#abs-non-replaced-width
|
||
let content_sizes = ContentSizesRequest::inline_if(
|
||
// If inline-size is non-auto, that value is used without shrink-to-fit
|
||
!node_info.style.inline_size_is_length() &&
|
||
// If it is, then the only case where shrink-to-fit is *not* used is
|
||
// if both offsets are non-auto, leaving inline-size as the only variable
|
||
// in the constraint equation.
|
||
!node_info.style.inline_box_offsets_are_both_non_auto(),
|
||
);
|
||
Self {
|
||
contents: IndependentFormattingContext::construct(
|
||
context,
|
||
node_info,
|
||
display_inside,
|
||
contents,
|
||
content_sizes,
|
||
// Text decorations are not propagated to any out-of-flow descendants.
|
||
TextDecorationLine::NONE,
|
||
),
|
||
}
|
||
}
|
||
|
||
pub(crate) fn to_hoisted(
|
||
self_: ArcRefCell<Self>,
|
||
initial_start_corner: Vec2<Length>,
|
||
tree_rank: usize,
|
||
containing_block: &ContainingBlock,
|
||
) -> HoistedAbsolutelyPositionedBox {
|
||
fn absolute_box_offsets(
|
||
initial_static_start: Length,
|
||
start: LengthPercentageOrAuto<'_>,
|
||
end: LengthPercentageOrAuto<'_>,
|
||
) -> AbsoluteBoxOffsets {
|
||
match (start.non_auto(), end.non_auto()) {
|
||
(None, None) => AbsoluteBoxOffsets::StaticStart {
|
||
start: initial_static_start,
|
||
},
|
||
(Some(start), Some(end)) => AbsoluteBoxOffsets::Both {
|
||
start: start.clone(),
|
||
end: end.clone(),
|
||
},
|
||
(None, Some(end)) => AbsoluteBoxOffsets::End { end: end.clone() },
|
||
(Some(start), None) => AbsoluteBoxOffsets::Start {
|
||
start: start.clone(),
|
||
},
|
||
}
|
||
}
|
||
|
||
let box_offsets = {
|
||
let box_ = self_.borrow();
|
||
let box_offsets = box_.contents.style.box_offsets(containing_block);
|
||
Vec2 {
|
||
inline: absolute_box_offsets(
|
||
initial_start_corner.inline,
|
||
box_offsets.inline_start,
|
||
box_offsets.inline_end,
|
||
),
|
||
block: absolute_box_offsets(
|
||
initial_start_corner.block,
|
||
box_offsets.block_start,
|
||
box_offsets.block_end,
|
||
),
|
||
}
|
||
};
|
||
HoistedAbsolutelyPositionedBox {
|
||
tree_rank,
|
||
box_offsets,
|
||
fragment: ArcRefCell::new(None),
|
||
absolutely_positioned_box: self_,
|
||
}
|
||
}
|
||
}
|
||
|
||
impl PositioningContext {
|
||
pub(crate) fn new_for_containing_block_for_all_descendants() -> Self {
|
||
Self {
|
||
for_nearest_positioned_ancestor: None,
|
||
for_nearest_containing_block_for_all_descendants: Vec::new(),
|
||
}
|
||
}
|
||
|
||
pub(crate) fn new_for_rayon(collects_for_nearest_positioned_ancestor: bool) -> Self {
|
||
Self {
|
||
for_nearest_positioned_ancestor: if collects_for_nearest_positioned_ancestor {
|
||
Some(Vec::new())
|
||
} else {
|
||
None
|
||
},
|
||
for_nearest_containing_block_for_all_descendants: Vec::new(),
|
||
}
|
||
}
|
||
|
||
pub(crate) fn collects_for_nearest_positioned_ancestor(&self) -> bool {
|
||
self.for_nearest_positioned_ancestor.is_some()
|
||
}
|
||
|
||
pub(crate) fn new_for_style(style: &ComputedValues) -> Option<Self> {
|
||
if style.establishes_containing_block_for_all_descendants() {
|
||
Some(Self::new_for_containing_block_for_all_descendants())
|
||
} else if style.establishes_containing_block() {
|
||
Some(Self {
|
||
for_nearest_positioned_ancestor: Some(Vec::new()),
|
||
for_nearest_containing_block_for_all_descendants: Vec::new(),
|
||
})
|
||
} else {
|
||
None
|
||
}
|
||
}
|
||
|
||
/// Given `fragment_layout_fn`, a closure which lays out a fragment in a provided
|
||
/// `PositioningContext`, create a new positioning context if necessary for the fragment and
|
||
/// lay out the fragment and all its children. Returns the newly created `BoxFragment`.
|
||
pub(crate) fn layout_maybe_position_relative_fragment(
|
||
&mut self,
|
||
layout_context: &LayoutContext,
|
||
containing_block: &ContainingBlock,
|
||
style: &ComputedValues,
|
||
fragment_layout_fn: impl FnOnce(&mut Self) -> BoxFragment,
|
||
) -> BoxFragment {
|
||
// Try to create a context, but if one isn't necessary, simply create the fragment
|
||
// using the given closure and the current `PositioningContext`.
|
||
let mut new_context = match Self::new_for_style(style) {
|
||
Some(new_context) => new_context,
|
||
None => return fragment_layout_fn(self),
|
||
};
|
||
|
||
let mut new_fragment = fragment_layout_fn(&mut new_context);
|
||
new_context.layout_collected_children(layout_context, &mut new_fragment);
|
||
|
||
// If the new context has any hoisted boxes for the nearest containing block for
|
||
// all descendants than collect them and pass them up the tree.
|
||
vec_append_owned(
|
||
&mut self.for_nearest_containing_block_for_all_descendants,
|
||
new_context.for_nearest_containing_block_for_all_descendants,
|
||
);
|
||
|
||
if style.clone_position() == Position::Relative {
|
||
new_fragment.content_rect.start_corner +=
|
||
&relative_adjustement(style, containing_block);
|
||
}
|
||
|
||
new_fragment
|
||
}
|
||
|
||
/// Given `fragment_layout_fn`, a closure which lays out a fragment in a provided
|
||
/// `PositioningContext`, create a positioning context for a positioned fragment and lay out
|
||
/// the fragment and all its children. Returns the resulting `BoxFragment`.
|
||
fn create_and_layout_positioned(
|
||
layout_context: &LayoutContext,
|
||
style: &ComputedValues,
|
||
for_nearest_containing_block_for_all_descendants: &mut Vec<HoistedAbsolutelyPositionedBox>,
|
||
fragment_layout_fn: impl FnOnce(&mut Self) -> BoxFragment,
|
||
) -> BoxFragment {
|
||
let mut new_context = match Self::new_for_style(style) {
|
||
Some(new_context) => new_context,
|
||
None => unreachable!(),
|
||
};
|
||
|
||
let mut new_fragment = fragment_layout_fn(&mut new_context);
|
||
new_context.layout_collected_children(layout_context, &mut new_fragment);
|
||
for_nearest_containing_block_for_all_descendants
|
||
.extend(new_context.for_nearest_containing_block_for_all_descendants);
|
||
new_fragment
|
||
}
|
||
|
||
// Lay out the hoisted boxes collected into this `PositioningContext` and add them
|
||
// to the given `BoxFragment`.
|
||
pub fn layout_collected_children(
|
||
&mut self,
|
||
layout_context: &LayoutContext,
|
||
new_fragment: &mut BoxFragment,
|
||
) {
|
||
let padding_rect = Rect {
|
||
size: new_fragment.content_rect.size.clone(),
|
||
// Ignore the content rect’s position in its own containing block:
|
||
start_corner: Vec2::zero(),
|
||
}
|
||
.inflate(&new_fragment.padding);
|
||
let containing_block = DefiniteContainingBlock {
|
||
size: padding_rect.size.clone(),
|
||
style: &new_fragment.style,
|
||
};
|
||
|
||
let take_hoisted_boxes_pending_layout = |context: &mut Self| match context
|
||
.for_nearest_positioned_ancestor
|
||
.as_mut()
|
||
{
|
||
Some(fragments) => std::mem::take(fragments),
|
||
None => std::mem::take(&mut context.for_nearest_containing_block_for_all_descendants),
|
||
};
|
||
|
||
// Loop because it’s possible that we discover (the static position of)
|
||
// more absolutely-positioned boxes while doing layout for others.
|
||
let mut hoisted_boxes = take_hoisted_boxes_pending_layout(self);
|
||
let mut laid_out_child_fragments = Vec::new();
|
||
while !hoisted_boxes.is_empty() {
|
||
HoistedAbsolutelyPositionedBox::layout_many(
|
||
layout_context,
|
||
&mut hoisted_boxes,
|
||
&mut laid_out_child_fragments,
|
||
&mut self.for_nearest_containing_block_for_all_descendants,
|
||
&containing_block,
|
||
);
|
||
hoisted_boxes = take_hoisted_boxes_pending_layout(self);
|
||
}
|
||
|
||
new_fragment.children.extend(laid_out_child_fragments);
|
||
}
|
||
|
||
pub(crate) fn push(&mut self, box_: HoistedAbsolutelyPositionedBox) {
|
||
if let Some(nearest) = &mut self.for_nearest_positioned_ancestor {
|
||
let position = box_
|
||
.absolutely_positioned_box
|
||
.borrow()
|
||
.contents
|
||
.style
|
||
.clone_position();
|
||
match position {
|
||
Position::Fixed => {}, // fall through
|
||
Position::Absolute => return nearest.push(box_),
|
||
Position::Static | Position::Relative => unreachable!(),
|
||
}
|
||
}
|
||
self.for_nearest_containing_block_for_all_descendants
|
||
.push(box_)
|
||
}
|
||
|
||
pub(crate) fn append(&mut self, other: Self) {
|
||
vec_append_owned(
|
||
&mut self.for_nearest_containing_block_for_all_descendants,
|
||
other.for_nearest_containing_block_for_all_descendants,
|
||
);
|
||
match (
|
||
self.for_nearest_positioned_ancestor.as_mut(),
|
||
other.for_nearest_positioned_ancestor,
|
||
) {
|
||
(Some(a), Some(b)) => vec_append_owned(a, b),
|
||
(None, None) => {},
|
||
_ => unreachable!(),
|
||
}
|
||
}
|
||
|
||
pub(crate) fn adjust_static_positions(
|
||
&mut self,
|
||
tree_rank_in_parent: usize,
|
||
f: impl FnOnce(&mut Self) -> Vec<Fragment>,
|
||
) -> Vec<Fragment> {
|
||
let for_containing_block_for_all_descendants =
|
||
self.for_nearest_containing_block_for_all_descendants.len();
|
||
let for_nearest_so_far = self
|
||
.for_nearest_positioned_ancestor
|
||
.as_ref()
|
||
.map(|v| v.len());
|
||
|
||
let fragments = f(self);
|
||
|
||
adjust_static_positions(
|
||
&mut self.for_nearest_containing_block_for_all_descendants
|
||
[for_containing_block_for_all_descendants..],
|
||
&fragments,
|
||
tree_rank_in_parent,
|
||
);
|
||
if let Some(nearest) = &mut self.for_nearest_positioned_ancestor {
|
||
adjust_static_positions(
|
||
&mut nearest[for_nearest_so_far.unwrap()..],
|
||
&fragments,
|
||
tree_rank_in_parent,
|
||
);
|
||
}
|
||
fragments
|
||
}
|
||
|
||
pub(crate) fn layout_initial_containing_block_children(
|
||
&mut self,
|
||
layout_context: &LayoutContext,
|
||
initial_containing_block: &DefiniteContainingBlock,
|
||
fragments: &mut Vec<ArcRefCell<Fragment>>,
|
||
) {
|
||
debug_assert!(self.for_nearest_positioned_ancestor.is_none());
|
||
|
||
// Loop because it’s possible that we discover (the static position of)
|
||
// more absolutely-positioned boxes while doing layout for others.
|
||
while !self
|
||
.for_nearest_containing_block_for_all_descendants
|
||
.is_empty()
|
||
{
|
||
HoistedAbsolutelyPositionedBox::layout_many(
|
||
layout_context,
|
||
&mut std::mem::take(&mut self.for_nearest_containing_block_for_all_descendants),
|
||
fragments,
|
||
&mut self.for_nearest_containing_block_for_all_descendants,
|
||
initial_containing_block,
|
||
)
|
||
}
|
||
}
|
||
}
|
||
|
||
impl HoistedAbsolutelyPositionedBox {
|
||
pub(crate) fn layout_many(
|
||
layout_context: &LayoutContext,
|
||
boxes: &mut [Self],
|
||
fragments: &mut Vec<ArcRefCell<Fragment>>,
|
||
for_nearest_containing_block_for_all_descendants: &mut Vec<HoistedAbsolutelyPositionedBox>,
|
||
containing_block: &DefiniteContainingBlock,
|
||
) {
|
||
if layout_context.use_rayon {
|
||
fragments.par_extend(boxes.par_iter_mut().mapfold_reduce_into(
|
||
for_nearest_containing_block_for_all_descendants,
|
||
|for_nearest_containing_block_for_all_descendants, box_| {
|
||
let new_fragment = ArcRefCell::new(Fragment::Box(box_.layout(
|
||
layout_context,
|
||
for_nearest_containing_block_for_all_descendants,
|
||
containing_block,
|
||
)));
|
||
|
||
*box_.fragment.borrow_mut() = Some(new_fragment.clone());
|
||
new_fragment
|
||
},
|
||
Vec::new,
|
||
vec_append_owned,
|
||
))
|
||
} else {
|
||
fragments.extend(boxes.iter_mut().map(|box_| {
|
||
let new_fragment = ArcRefCell::new(Fragment::Box(box_.layout(
|
||
layout_context,
|
||
for_nearest_containing_block_for_all_descendants,
|
||
containing_block,
|
||
)));
|
||
*box_.fragment.borrow_mut() = Some(new_fragment.clone());
|
||
new_fragment
|
||
}))
|
||
}
|
||
}
|
||
|
||
pub(crate) fn layout(
|
||
&mut self,
|
||
layout_context: &LayoutContext,
|
||
for_nearest_containing_block_for_all_descendants: &mut Vec<HoistedAbsolutelyPositionedBox>,
|
||
containing_block: &DefiniteContainingBlock,
|
||
) -> BoxFragment {
|
||
let cbis = containing_block.size.inline;
|
||
let cbbs = containing_block.size.block;
|
||
let absolutely_positioned_box = self.absolutely_positioned_box.borrow_mut();
|
||
let style = &absolutely_positioned_box.contents.style;
|
||
let pbm = style.padding_border_margin(&containing_block.into());
|
||
|
||
let size;
|
||
let replaced_used_size;
|
||
match absolutely_positioned_box.contents.as_replaced() {
|
||
Ok(replaced) => {
|
||
// https://drafts.csswg.org/css2/visudet.html#abs-replaced-width
|
||
// https://drafts.csswg.org/css2/visudet.html#abs-replaced-height
|
||
let used_size =
|
||
replaced.used_size_as_if_inline_element(&containing_block.into(), style, &pbm);
|
||
size = Vec2 {
|
||
inline: LengthOrAuto::LengthPercentage(used_size.inline),
|
||
block: LengthOrAuto::LengthPercentage(used_size.block),
|
||
};
|
||
replaced_used_size = Some(used_size);
|
||
},
|
||
Err(_non_replaced) => {
|
||
size = style.content_box_size(&containing_block.into(), &pbm);
|
||
replaced_used_size = None;
|
||
},
|
||
}
|
||
|
||
let inline_axis = solve_axis(
|
||
cbis,
|
||
pbm.padding_border_sums.inline,
|
||
pbm.margin.inline_start,
|
||
pbm.margin.inline_end,
|
||
/* avoid_negative_margin_start */ true,
|
||
&self.box_offsets.inline,
|
||
size.inline,
|
||
);
|
||
|
||
let block_axis = solve_axis(
|
||
cbis,
|
||
pbm.padding_border_sums.block,
|
||
pbm.margin.block_start,
|
||
pbm.margin.block_end,
|
||
/* avoid_negative_margin_start */ false,
|
||
&self.box_offsets.block,
|
||
size.block,
|
||
);
|
||
|
||
let margin = Sides {
|
||
inline_start: inline_axis.margin_start,
|
||
inline_end: inline_axis.margin_end,
|
||
block_start: block_axis.margin_start,
|
||
block_end: block_axis.margin_end,
|
||
};
|
||
|
||
PositioningContext::create_and_layout_positioned(
|
||
layout_context,
|
||
style,
|
||
for_nearest_containing_block_for_all_descendants,
|
||
|positioning_context| {
|
||
let size;
|
||
let fragments;
|
||
match absolutely_positioned_box.contents.as_replaced() {
|
||
Ok(replaced) => {
|
||
// https://drafts.csswg.org/css2/visudet.html#abs-replaced-width
|
||
// https://drafts.csswg.org/css2/visudet.html#abs-replaced-height
|
||
let style = &absolutely_positioned_box.contents.style;
|
||
size = replaced_used_size.unwrap();
|
||
fragments = replaced.make_fragments(style, size.clone());
|
||
},
|
||
Err(non_replaced) => {
|
||
// https://drafts.csswg.org/css2/visudet.html#abs-non-replaced-width
|
||
// https://drafts.csswg.org/css2/visudet.html#abs-non-replaced-height
|
||
let inline_size = inline_axis.size.auto_is(|| {
|
||
let anchor = match inline_axis.anchor {
|
||
Anchor::Start(start) => start,
|
||
Anchor::End(end) => end,
|
||
};
|
||
let available_size = cbis -
|
||
anchor -
|
||
pbm.padding_border_sums.inline -
|
||
margin.inline_sum();
|
||
absolutely_positioned_box
|
||
.contents
|
||
.content_sizes
|
||
.shrink_to_fit(available_size)
|
||
});
|
||
|
||
let containing_block_for_children = ContainingBlock {
|
||
inline_size,
|
||
block_size: block_axis.size,
|
||
style,
|
||
};
|
||
// https://drafts.csswg.org/css-writing-modes/#orthogonal-flows
|
||
assert_eq!(
|
||
containing_block.style.writing_mode,
|
||
containing_block_for_children.style.writing_mode,
|
||
"Mixed writing modes are not supported yet"
|
||
);
|
||
let dummy_tree_rank = 0;
|
||
let independent_layout = non_replaced.layout(
|
||
layout_context,
|
||
positioning_context,
|
||
&containing_block_for_children,
|
||
dummy_tree_rank,
|
||
);
|
||
|
||
size = Vec2 {
|
||
inline: inline_size,
|
||
block: block_axis
|
||
.size
|
||
.auto_is(|| independent_layout.content_block_size),
|
||
};
|
||
fragments = independent_layout.fragments
|
||
},
|
||
};
|
||
|
||
let pb = &pbm.padding + &pbm.border;
|
||
let inline_start = match inline_axis.anchor {
|
||
Anchor::Start(start) => start + pb.inline_start + margin.inline_start,
|
||
Anchor::End(end) => {
|
||
cbis - end - pb.inline_end - margin.inline_end - size.inline
|
||
},
|
||
};
|
||
let block_start = match block_axis.anchor {
|
||
Anchor::Start(start) => start + pb.block_start + margin.block_start,
|
||
Anchor::End(end) => cbbs - end - pb.block_end - margin.block_end - size.block,
|
||
};
|
||
|
||
let content_rect = Rect {
|
||
start_corner: Vec2 {
|
||
inline: inline_start,
|
||
block: block_start,
|
||
},
|
||
size,
|
||
};
|
||
|
||
BoxFragment::new(
|
||
absolutely_positioned_box.contents.tag,
|
||
style.clone(),
|
||
fragments,
|
||
content_rect,
|
||
pbm.padding,
|
||
pbm.border,
|
||
margin,
|
||
CollapsedBlockMargins::zero(),
|
||
)
|
||
},
|
||
)
|
||
}
|
||
}
|
||
|
||
enum Anchor {
|
||
Start(Length),
|
||
End(Length),
|
||
}
|
||
|
||
struct AxisResult {
|
||
anchor: Anchor,
|
||
size: LengthOrAuto,
|
||
margin_start: Length,
|
||
margin_end: Length,
|
||
}
|
||
|
||
/// This unifies some of the parts in common in:
|
||
///
|
||
/// * https://drafts.csswg.org/css2/visudet.html#abs-non-replaced-width
|
||
/// * https://drafts.csswg.org/css2/visudet.html#abs-non-replaced-height
|
||
///
|
||
/// … and:
|
||
///
|
||
/// * https://drafts.csswg.org/css2/visudet.html#abs-replaced-width
|
||
/// * https://drafts.csswg.org/css2/visudet.html#abs-replaced-height
|
||
///
|
||
/// In the replaced case, `size` is never `Auto`.
|
||
fn solve_axis(
|
||
containing_size: Length,
|
||
padding_border_sum: Length,
|
||
computed_margin_start: LengthOrAuto,
|
||
computed_margin_end: LengthOrAuto,
|
||
avoid_negative_margin_start: bool,
|
||
box_offsets: &AbsoluteBoxOffsets,
|
||
size: LengthOrAuto,
|
||
) -> AxisResult {
|
||
match box_offsets {
|
||
AbsoluteBoxOffsets::StaticStart { start } => AxisResult {
|
||
anchor: Anchor::Start(*start),
|
||
size,
|
||
margin_start: computed_margin_start.auto_is(Length::zero),
|
||
margin_end: computed_margin_end.auto_is(Length::zero),
|
||
},
|
||
AbsoluteBoxOffsets::Start { start } => AxisResult {
|
||
anchor: Anchor::Start(start.percentage_relative_to(containing_size)),
|
||
size,
|
||
margin_start: computed_margin_start.auto_is(Length::zero),
|
||
margin_end: computed_margin_end.auto_is(Length::zero),
|
||
},
|
||
AbsoluteBoxOffsets::End { end } => AxisResult {
|
||
anchor: Anchor::End(end.percentage_relative_to(containing_size)),
|
||
size,
|
||
margin_start: computed_margin_start.auto_is(Length::zero),
|
||
margin_end: computed_margin_end.auto_is(Length::zero),
|
||
},
|
||
AbsoluteBoxOffsets::Both { start, end } => {
|
||
let start = start.percentage_relative_to(containing_size);
|
||
let end = end.percentage_relative_to(containing_size);
|
||
|
||
let margin_start;
|
||
let margin_end;
|
||
let used_size;
|
||
if let LengthOrAuto::LengthPercentage(s) = size {
|
||
used_size = s;
|
||
let margins = containing_size - start - end - padding_border_sum - s;
|
||
match (computed_margin_start, computed_margin_end) {
|
||
(LengthOrAuto::Auto, LengthOrAuto::Auto) => {
|
||
if avoid_negative_margin_start && margins < Length::zero() {
|
||
margin_start = Length::zero();
|
||
margin_end = margins;
|
||
} else {
|
||
margin_start = margins / 2.;
|
||
margin_end = margins / 2.;
|
||
}
|
||
},
|
||
(LengthOrAuto::Auto, LengthOrAuto::LengthPercentage(end)) => {
|
||
margin_start = margins - end;
|
||
margin_end = end;
|
||
},
|
||
(LengthOrAuto::LengthPercentage(start), LengthOrAuto::Auto) => {
|
||
margin_start = start;
|
||
margin_end = margins - start;
|
||
},
|
||
(
|
||
LengthOrAuto::LengthPercentage(start),
|
||
LengthOrAuto::LengthPercentage(end),
|
||
) => {
|
||
margin_start = start;
|
||
margin_end = end;
|
||
},
|
||
}
|
||
} else {
|
||
margin_start = computed_margin_start.auto_is(Length::zero);
|
||
margin_end = computed_margin_end.auto_is(Length::zero);
|
||
// FIXME(nox): What happens if that is negative?
|
||
used_size =
|
||
containing_size - start - end - padding_border_sum - margin_start - margin_end
|
||
};
|
||
AxisResult {
|
||
anchor: Anchor::Start(start),
|
||
size: LengthOrAuto::LengthPercentage(used_size),
|
||
margin_start,
|
||
margin_end,
|
||
}
|
||
},
|
||
}
|
||
}
|
||
|
||
fn adjust_static_positions(
|
||
absolutely_positioned_fragments: &mut [HoistedAbsolutelyPositionedBox],
|
||
child_fragments: &[Fragment],
|
||
tree_rank_in_parent: usize,
|
||
) {
|
||
for abspos_fragment in absolutely_positioned_fragments {
|
||
let original_tree_rank = abspos_fragment.tree_rank;
|
||
abspos_fragment.tree_rank = tree_rank_in_parent;
|
||
|
||
let child_fragment_rect = match &child_fragments[original_tree_rank] {
|
||
Fragment::Box(b) => &b.content_rect,
|
||
Fragment::AbsoluteOrFixedPositioned(_) => continue,
|
||
Fragment::Anonymous(a) => &a.rect,
|
||
_ => unreachable!(),
|
||
};
|
||
|
||
if let AbsoluteBoxOffsets::StaticStart { start } = &mut abspos_fragment.box_offsets.inline {
|
||
*start += child_fragment_rect.start_corner.inline;
|
||
}
|
||
|
||
if let AbsoluteBoxOffsets::StaticStart { start } = &mut abspos_fragment.box_offsets.block {
|
||
*start += child_fragment_rect.start_corner.block;
|
||
}
|
||
}
|
||
}
|
||
|
||
fn vec_append_owned<T>(a: &mut Vec<T>, mut b: Vec<T>) {
|
||
if a.is_empty() {
|
||
*a = b
|
||
} else {
|
||
a.append(&mut b)
|
||
}
|
||
}
|
||
|
||
/// https://drafts.csswg.org/css2/visuren.html#relative-positioning
|
||
pub(crate) fn relative_adjustement(
|
||
style: &ComputedValues,
|
||
containing_block: &ContainingBlock,
|
||
) -> Vec2<Length> {
|
||
let cbis = containing_block.inline_size;
|
||
let cbbs = containing_block.block_size.auto_is(Length::zero);
|
||
let box_offsets = style
|
||
.box_offsets(containing_block)
|
||
.map_inline_and_block_axes(
|
||
|v| v.percentage_relative_to(cbis),
|
||
|v| v.percentage_relative_to(cbbs),
|
||
);
|
||
fn adjust(start: LengthOrAuto, end: LengthOrAuto) -> Length {
|
||
match (start, end) {
|
||
(LengthOrAuto::Auto, LengthOrAuto::Auto) => Length::zero(),
|
||
(LengthOrAuto::Auto, LengthOrAuto::LengthPercentage(end)) => -end,
|
||
(LengthOrAuto::LengthPercentage(start), _) => start,
|
||
}
|
||
}
|
||
Vec2 {
|
||
inline: adjust(box_offsets.inline_start, box_offsets.inline_end),
|
||
block: adjust(box_offsets.block_start, box_offsets.block_end),
|
||
}
|
||
}
|