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//! The tree layouter layouts trees (i.e.
//! [syntax trees](crate::syntax::SyntaxTree) and [functions](crate::func))
//! by executing commands issued by the trees.
use crate::{Pass, Feedback, DynFuture};
use crate::style::LayoutStyle;
use crate::syntax::decoration::Decoration;
use crate::syntax::tree::{SyntaxTree, SyntaxNode, DynamicNode};
use crate::syntax::span::{Span, Spanned};
use super::line::{LineLayouter, LineContext};
use super::text::{layout_text, TextContext};
use super::*;
/// Performs the tree layouting.
#[derive(Debug)]
pub struct TreeLayouter<'a> {
ctx: LayoutContext<'a>,
layouter: LineLayouter,
style: LayoutStyle,
feedback: Feedback,
}
impl<'a> TreeLayouter<'a> {
/// Create a new tree layouter.
pub fn new(ctx: LayoutContext<'a>) -> TreeLayouter<'a> {
TreeLayouter {
layouter: LineLayouter::new(LineContext {
spaces: ctx.spaces.clone(),
axes: ctx.axes,
align: ctx.align,
repeat: ctx.repeat,
line_spacing: ctx.style.text.line_spacing(),
}),
style: ctx.style.clone(),
ctx,
feedback: Feedback::new(),
}
}
/// Layout a syntax tree by directly processing the nodes instead of using
/// the command based architecture.
pub async fn layout_tree(&mut self, tree: &SyntaxTree) {
for node in tree {
self.layout_node(node).await;
}
}
pub async fn layout_node(&mut self, node: &Spanned<SyntaxNode>) {
let decorate = |this: &mut TreeLayouter, deco| {
this.feedback.decorations.push(Spanned::new(deco, node.span));
};
match &node.v {
SyntaxNode::Space => self.layout_space(),
SyntaxNode::Parbreak => self.layout_paragraph(),
SyntaxNode::Linebreak => self.layouter.finish_line(),
SyntaxNode::Text(text) => {
if self.style.text.italic {
decorate(self, Decoration::Italic);
}
if self.style.text.bolder {
decorate(self, Decoration::Bold);
}
self.layout_text(text).await;
}
SyntaxNode::ToggleItalic => {
self.style.text.italic = !self.style.text.italic;
decorate(self, Decoration::Italic);
}
SyntaxNode::ToggleBolder => {
self.style.text.bolder = !self.style.text.bolder;
decorate(self, Decoration::Bold);
}
SyntaxNode::Raw(lines) => {
// TODO: Make this more efficient.
let fallback = self.style.text.fallback.clone();
self.style.text.fallback.list_mut().insert(0, "monospace".to_string());
self.style.text.fallback.flatten();
// Layout the first line.
let mut iter = lines.iter();
if let Some(line) = iter.next() {
self.layout_text(line).await;
}
// Put a newline before each following line.
for line in iter {
self.layouter.finish_line();
self.layout_text(line).await;
}
self.style.text.fallback = fallback;
}
SyntaxNode::Dyn(dynamic) => {
self.layout_dyn(Spanned::new(dynamic.as_ref(), node.span)).await;
}
}
}
/// Layout a node into this layouting process.
pub async fn layout_dyn(&mut self, dynamic: Spanned<&dyn DynamicNode>) {
// Execute the tree's layout function which generates the commands.
let layouted = dynamic.v.layout(LayoutContext {
style: &self.style,
spaces: self.layouter.remaining(),
nested: true,
.. self.ctx
}).await;
// Add the errors generated by the tree to the error list.
self.feedback.extend_offset(layouted.feedback, dynamic.span.start);
for command in layouted.output {
self.execute_command(command, dynamic.span).await;
}
}
/// Compute the finished list of boxes.
pub fn finish(self) -> Pass<MultiLayout> {
Pass::new(self.layouter.finish(), self.feedback)
}
/// Execute a command issued by a tree. When the command is errorful, the
/// given span is stored with the error.
fn execute_command<'r>(
&'r mut self,
command: Command<'r>,
tree_span: Span,
) -> DynFuture<'r, ()> { Box::pin(async move {
use Command::*;
match command {
LayoutSyntaxTree(tree) => self.layout_tree(tree).await,
Add(layout) => self.layouter.add(layout),
AddMultiple(layouts) => self.layouter.add_multiple(layouts),
AddSpacing(space, kind, axis) => match axis {
Primary => self.layouter.add_primary_spacing(space, kind),
Secondary => self.layouter.add_secondary_spacing(space, kind),
}
BreakLine => self.layouter.finish_line(),
BreakParagraph => self.layout_paragraph(),
BreakPage => {
if self.ctx.nested {
error!(
@self.feedback, tree_span,
"page break cannot be issued from nested context",
);
} else {
self.layouter.finish_space(true)
}
}
SetTextStyle(style) => {
self.layouter.set_line_spacing(style.line_spacing());
self.style.text = style;
}
SetPageStyle(style) => {
if self.ctx.nested {
error!(
@self.feedback, tree_span,
"page style cannot be changed from nested context",
);
} else {
self.style.page = style;
// The line layouter has no idea of page styles and thus we
// need to recompute the layouting space resulting of the
// new page style and update it within the layouter.
let margins = style.margins();
self.ctx.base = style.size.unpadded(margins);
self.layouter.set_spaces(vec![
LayoutSpace {
size: style.size,
padding: margins,
expansion: LayoutExpansion::new(true, true),
}
], true);
}
}
SetAlignment(align) => self.ctx.align = align,
SetAxes(axes) => {
self.layouter.set_axes(axes);
self.ctx.axes = axes;
}
}
}) }
/// Layout a continous piece of text and add it to the line layouter.
async fn layout_text(&mut self, text: &str) {
self.layouter.add(layout_text(text, TextContext {
loader: &self.ctx.loader,
style: &self.style.text,
axes: self.ctx.axes,
align: self.ctx.align,
}).await)
}
/// Add the spacing for a syntactic space node.
fn layout_space(&mut self) {
self.layouter.add_primary_spacing(
self.style.text.word_spacing(),
SpacingKind::WORD,
);
}
/// Finish the paragraph and add paragraph spacing.
fn layout_paragraph(&mut self) {
self.layouter.add_secondary_spacing(
self.style.text.paragraph_spacing(),
SpacingKind::PARAGRAPH,
);
}
}
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