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use super::*;
/// Layouts syntax trees into boxes.
pub fn layout_tree(tree: &SyntaxTree, ctx: LayoutContext) -> LayoutResult<MultiLayout> {
let mut layouter = TreeLayouter::new(ctx);
layouter.layout(tree)?;
layouter.finish()
}
#[derive(Debug, Clone)]
struct TreeLayouter<'a, 'p> {
ctx: LayoutContext<'a, 'p>,
stack: StackLayouter,
flex: FlexLayouter,
style: Cow<'a, TextStyle>,
}
impl<'a, 'p> TreeLayouter<'a, 'p> {
/// Create a new layouter.
fn new(ctx: LayoutContext<'a, 'p>) -> TreeLayouter<'a, 'p> {
TreeLayouter {
ctx,
stack: StackLayouter::new(StackContext {
spaces: ctx.spaces,
axes: ctx.axes,
}),
flex: FlexLayouter::new(FlexContext {
flex_spacing: flex_spacing(&ctx.style),
spaces: ctx.spaces.iter().map(|space| space.usable_space(true)).collect(),
axes: ctx.axes,
}),
style: Cow::Borrowed(ctx.style),
}
}
/// Layout a syntax tree.
fn layout(&mut self, tree: &SyntaxTree) -> LayoutResult<()> {
for node in &tree.nodes {
match &node.val {
Node::Text(text) => {
self.flex.add(layout_text(text, TextContext {
loader: &self.ctx.loader,
style: &self.style,
})?);
}
Node::Space => {
if !self.flex.is_empty() {
self.flex.add_space(self.style.word_spacing * self.style.font_size);
}
}
Node::Newline => {
if !self.flex.is_empty() {
self.finish_paragraph()?;
}
}
Node::ToggleItalics => self.style.to_mut().toggle_class(FontClass::Italic),
Node::ToggleBold => self.style.to_mut().toggle_class(FontClass::Bold),
Node::ToggleMonospace => self.style.to_mut().toggle_class(FontClass::Monospace),
Node::Func(func) => self.layout_func(func)?,
}
}
Ok(())
}
/// Layout a function.
fn layout_func(&mut self, func: &FuncCall) -> LayoutResult<()> {
// Finish the current flex layout on a copy to find out how
// much space would be remaining if we finished.
let mut lookahead = self.stack.clone();
lookahead.add_multiple(self.flex.clone().finish()?)?;
let spaces = lookahead.remaining(true);
let commands = func.body.val.layout(LayoutContext {
style: &self.style,
spaces,
.. self.ctx
})?;
for command in commands {
self.execute(command)?;
}
Ok(())
}
fn execute(&mut self, command: Command) -> LayoutResult<()> {
match command {
Command::LayoutTree(tree) => self.layout(tree)?,
Command::Add(layout) => self.flex.add(layout),
Command::AddMultiple(layouts) => self.flex.add_multiple(layouts),
Command::FinishFlexRun => self.flex.add_break(),
Command::FinishFlexLayout => self.finish_paragraph()?,
Command::FinishLayout => self.finish_layout(true)?,
Command::SetStyle(style) => *self.style.to_mut() = style,
Command::SetAxes(axes) => {
if axes.secondary != self.ctx.axes.secondary {
self.stack.set_axis(axes.secondary);
} else if axes.primary != self.ctx.axes.primary {
self.flex.set_axis(axes.primary);
}
self.ctx.axes = axes;
}
}
Ok(())
}
/// Finish the layout.
fn finish(mut self) -> LayoutResult<MultiLayout> {
self.finish_flex()?;
Ok(self.stack.finish())
}
/// Finish the current stack layout.
fn finish_layout(&mut self, include_empty: bool) -> LayoutResult<()> {
self.finish_flex()?;
self.stack.finish_layout(include_empty);
self.start_new_flex();
Ok(())
}
/// Finish the current flex layout and add space after it.
fn finish_paragraph(&mut self) -> LayoutResult<()> {
self.finish_flex()?;
self.stack.add_space(paragraph_spacing(&self.style));
self.start_new_flex();
Ok(())
}
/// Finish the current flex layout and add it the stack.
fn finish_flex(&mut self) -> LayoutResult<()> {
if !self.flex.is_empty() {
let layouts = self.flex.finish()?;
self.stack.add_multiple(layouts)?;
}
Ok(())
}
/// Start a new flex layout.
fn start_new_flex(&mut self) {
self.flex = FlexLayouter::new(FlexContext {
flex_spacing: flex_spacing(&self.style),
spaces: self.stack.remaining(true),
axes: self.ctx.axes,
});
}
}
fn flex_spacing(style: &TextStyle) -> Size {
(style.line_spacing - 1.0) * style.font_size
}
fn paragraph_spacing(style: &TextStyle) -> Size {
(style.paragraph_spacing - 1.0) * style.font_size
}
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