53 lines
1.4 KiB
Rust
53 lines
1.4 KiB
Rust
use super::*;
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/// A node that adds padding to its child.
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#[derive(Debug, Clone, PartialEq)]
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pub struct PadNode {
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/// The amount of padding.
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pub padding: Sides<Linear>,
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/// The child node whose sides to pad.
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pub child: Node,
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}
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impl Layout for PadNode {
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fn layout(&self, ctx: &mut LayoutContext, areas: &Areas) -> Fragment {
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let areas = shrink(areas, self.padding);
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let mut layouted = self.child.layout(ctx, &areas);
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for frame in layouted.frames_mut() {
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pad(frame, self.padding);
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}
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layouted
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}
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}
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impl From<PadNode> for AnyNode {
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fn from(pad: PadNode) -> Self {
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Self::new(pad)
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}
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}
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/// Shrink all areas by the padding.
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fn shrink(areas: &Areas, padding: Sides<Linear>) -> Areas {
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let shrink = |size| size - padding.resolve(size).size();
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Areas {
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current: shrink(areas.current),
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full: shrink(areas.full),
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backlog: areas.backlog.iter().copied().map(shrink).collect(),
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last: areas.last.map(shrink),
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expand: areas.expand,
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}
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}
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/// Enlarge the frame and move all elements inwards.
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fn pad(frame: &mut Frame, padding: Sides<Linear>) {
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let padding = padding.resolve(frame.size);
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let origin = Point::new(padding.left, padding.top);
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frame.size += padding.size();
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for (point, _) in &mut frame.elements {
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*point += origin;
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}
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}
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