221 lines
7.5 KiB
Rust
221 lines
7.5 KiB
Rust
use super::*;
|
|
|
|
/// A node that arranges its children into a paragraph.
|
|
#[derive(Debug, Clone, PartialEq)]
|
|
pub struct NodePar {
|
|
/// The `main` and `cross` directions of this paragraph.
|
|
///
|
|
/// The children are placed in lines along the `cross` direction. The lines
|
|
/// are stacked along the `main` direction.
|
|
pub dirs: LayoutDirs,
|
|
/// Whether to expand the cross axis to fill the area or to fit the content.
|
|
pub cross_expansion: Expansion,
|
|
/// The spacing to insert after each line.
|
|
pub line_spacing: Length,
|
|
/// The nodes to be arranged in a paragraph.
|
|
pub children: Vec<Node>,
|
|
/// How to align this paragraph in _its_ parent.
|
|
pub align: ChildAlign,
|
|
}
|
|
|
|
impl Layout for NodePar {
|
|
fn layout(&self, ctx: &mut LayoutContext, areas: &Areas) -> Layouted {
|
|
let mut layouter = ParLayouter::new(self, areas.clone());
|
|
for child in &self.children {
|
|
match child.layout(ctx, &layouter.areas) {
|
|
Layouted::Spacing(spacing) => layouter.push_spacing(spacing),
|
|
Layouted::Frame(frame, align) => layouter.push_frame(frame, align.cross),
|
|
Layouted::Frames(frames, align) => {
|
|
for frame in frames {
|
|
layouter.push_frame(frame, align.cross);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
Layouted::Frames(layouter.finish(), self.align)
|
|
}
|
|
}
|
|
|
|
impl From<NodePar> for NodeAny {
|
|
fn from(par: NodePar) -> Self {
|
|
Self::new(par)
|
|
}
|
|
}
|
|
|
|
struct ParLayouter<'a> {
|
|
par: &'a NodePar,
|
|
main: SpecAxis,
|
|
cross: SpecAxis,
|
|
dirs: LayoutDirs,
|
|
areas: Areas,
|
|
finished: Vec<Frame>,
|
|
lines: Vec<(Length, Frame, Align)>,
|
|
lines_size: Gen<Length>,
|
|
line: Vec<(Length, Frame, Align)>,
|
|
line_size: Gen<Length>,
|
|
line_ruler: Align,
|
|
}
|
|
|
|
impl<'a> ParLayouter<'a> {
|
|
fn new(par: &'a NodePar, areas: Areas) -> Self {
|
|
Self {
|
|
par,
|
|
main: par.dirs.main.axis(),
|
|
cross: par.dirs.cross.axis(),
|
|
dirs: par.dirs,
|
|
areas,
|
|
finished: vec![],
|
|
lines: vec![],
|
|
lines_size: Gen::ZERO,
|
|
line: vec![],
|
|
line_size: Gen::ZERO,
|
|
line_ruler: Align::Start,
|
|
}
|
|
}
|
|
|
|
fn push_spacing(&mut self, amount: Length) {
|
|
let cross_max = self.areas.current.get(self.cross);
|
|
self.line_size.cross = (self.line_size.cross + amount).min(cross_max);
|
|
}
|
|
|
|
fn push_frame(&mut self, frame: Frame, align: Align) {
|
|
// When the alignment of the last pushed frame (stored in the "ruler")
|
|
// is further to the end than the new `frame`, we need a line break.
|
|
//
|
|
// For example
|
|
// ```
|
|
// #align(right)[First] #align(center)[Second]
|
|
// ```
|
|
// would be laid out as:
|
|
// +----------------------------+
|
|
// | First |
|
|
// | Second |
|
|
// +----------------------------+
|
|
if self.line_ruler > align {
|
|
self.finish_line();
|
|
}
|
|
|
|
// Find out whether the area still has enough space for this frame.
|
|
// Space occupied by previous lines is already removed from
|
|
// `areas.current`, but the cross-extent of the current line needs to be
|
|
// subtracted to make sure the frame fits.
|
|
let fits = {
|
|
let mut usable = self.areas.current;
|
|
*usable.get_mut(self.cross) -= self.line_size.cross;
|
|
usable.fits(frame.size)
|
|
};
|
|
|
|
if !fits {
|
|
self.finish_line();
|
|
|
|
// Here, we can directly check whether the frame fits into
|
|
// `areas.current` since we just called `finish_line`.
|
|
while !self.areas.current.fits(frame.size) {
|
|
if self.areas.in_full_last() {
|
|
// The frame fits nowhere.
|
|
// TODO: Should this be placed into the first area or the last?
|
|
// TODO: Produce diagnostic once the necessary spans exist.
|
|
break;
|
|
} else {
|
|
self.finish_area();
|
|
}
|
|
}
|
|
}
|
|
|
|
let size = frame.size.switch(self.dirs);
|
|
|
|
// A line can contain frames with different alignments. They exact
|
|
// positions are calculated later depending on the alignments.
|
|
self.line.push((self.line_size.cross, frame, align));
|
|
|
|
self.line_size.cross += size.cross;
|
|
self.line_size.main = self.line_size.main.max(size.main);
|
|
self.line_ruler = align;
|
|
}
|
|
|
|
fn finish_line(&mut self) {
|
|
let full_size = {
|
|
let full = self.areas.full.switch(self.dirs);
|
|
Gen::new(
|
|
self.line_size.main,
|
|
self.par
|
|
.cross_expansion
|
|
.resolve(self.line_size.cross.min(full.cross), full.cross),
|
|
)
|
|
};
|
|
|
|
let mut output = Frame::new(full_size.switch(self.dirs).to_size());
|
|
|
|
for (before, frame, align) in std::mem::take(&mut self.line) {
|
|
let child_cross_size = frame.size.get(self.cross);
|
|
|
|
// Position along the cross axis.
|
|
let cross = align.resolve(if self.dirs.cross.is_positive() {
|
|
let after_with_self = self.line_size.cross - before;
|
|
before .. full_size.cross - after_with_self
|
|
} else {
|
|
let before_with_self = before + child_cross_size;
|
|
let after = self.line_size.cross - (before + child_cross_size);
|
|
full_size.cross - before_with_self .. after
|
|
});
|
|
|
|
let pos = Gen::new(Length::ZERO, cross).switch(self.dirs).to_point();
|
|
output.push_frame(pos, frame);
|
|
}
|
|
|
|
// Add line spacing, but only between lines.
|
|
if !self.lines.is_empty() {
|
|
self.lines_size.main += self.par.line_spacing;
|
|
*self.areas.current.get_mut(self.main) -= self.par.line_spacing;
|
|
}
|
|
|
|
// Update metrics of the whole paragraph.
|
|
self.lines.push((self.lines_size.main, output, self.line_ruler));
|
|
self.lines_size.main += full_size.main;
|
|
self.lines_size.cross = self.lines_size.cross.max(full_size.cross);
|
|
*self.areas.current.get_mut(self.main) -= full_size.main;
|
|
|
|
// Reset metrics for the single line.
|
|
self.line_size = Gen::ZERO;
|
|
self.line_ruler = Align::Start;
|
|
}
|
|
|
|
fn finish_area(&mut self) {
|
|
let size = self.lines_size;
|
|
let mut output = Frame::new(size.switch(self.dirs).to_size());
|
|
|
|
for (before, line, cross_align) in std::mem::take(&mut self.lines) {
|
|
let child_size = line.size.switch(self.dirs);
|
|
|
|
// Position along the main axis.
|
|
let main = if self.dirs.main.is_positive() {
|
|
before
|
|
} else {
|
|
size.main - (before + child_size.main)
|
|
};
|
|
|
|
// Align along the cross axis.
|
|
let cross = cross_align.resolve(if self.dirs.cross.is_positive() {
|
|
Length::ZERO .. size.cross - child_size.cross
|
|
} else {
|
|
size.cross - child_size.cross .. Length::ZERO
|
|
});
|
|
|
|
let pos = Gen::new(main, cross).switch(self.dirs).to_point();
|
|
output.push_frame(pos, line);
|
|
}
|
|
|
|
self.finished.push(output);
|
|
self.areas.next();
|
|
|
|
// Reset metrics for the whole paragraph.
|
|
self.lines_size = Gen::ZERO;
|
|
}
|
|
|
|
fn finish(mut self) -> Vec<Frame> {
|
|
self.finish_line();
|
|
self.finish_area();
|
|
self.finished
|
|
}
|
|
}
|