Struct TextSpan

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pub struct TextSpan { /* private fields */ }

Expand description

A rich-text tree: each node carries a fragment of text, partial style overrides — whatever is unspecified inherits from the parent, so a .bold() child keeps its parent’s size — and children of its own.

let span = TextSpan::new("Hello ")
    .child(TextSpan::new("bold").bold())
    .child(TextSpan::new(" world"));
let runs = span.flatten(TextStyle::new(20.0));
assert_eq!(runs.len(), 3);
assert_eq!(runs[1].1.size, 20.0); // the bold child inherits the size

Implementations§

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impl TextSpan

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pub fn new(text: impl Into<String>) -> TextSpan

A text fragment with no overrides — it inherits everything.

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pub fn bold(self) -> TextSpan

Makes this subtree bold.

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pub fn weight(self, weight: FontWeight) -> TextSpan

Sets this subtree’s weight.

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pub fn italic(self) -> TextSpan

Makes this subtree italic.

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pub fn size(self, size: f32) -> TextSpan

Sets this subtree’s size.

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pub fn color(self, color: Color) -> TextSpan

Sets this subtree’s colour.

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pub fn underline(self) -> TextSpan

Underlines this subtree. It combines with the decoration already set on this node, but not with the parent’s.

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pub fn strikethrough(self) -> TextSpan

Strikes through this subtree.

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pub fn decoration(self, decoration: TextDecoration) -> TextSpan

Sets this subtree’s decoration lines.

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pub fn decoration_color(self, color: Color) -> TextSpan

Sets this subtree’s decoration colour.

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pub fn style(self, style: TextStyle) -> TextSpan

Applies a whole TextStyle as this subtree’s override, replacing whatever this span had said before.

It used to force every typographic field to answered, because a TextStyle could not say otherwise. It no longer has to: a style naming only a size now overrides only the size, and the weight goes on being inherited from the parent span.

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pub fn child(self, child: TextSpan) -> TextSpan

Adds a child, rendered after this node’s own text.

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pub fn flatten(&self, base: TextStyle) -> Vec<(String, ResolvedTextStyle)>

Flattens the tree into resolved runs (text, style), in reading order, cascading the overrides down from base, the paragraph’s default style. Nodes with no text of their own produce no empty run.

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pub fn measure_hash<H>(&self, hasher: &mut H)
where H: Hasher,

Mixes into hasher everything that affects the tree’s measurement: text, sizes, weights and italics. Colours and decorations are excluded, having no effect on geometry. This serves as the measurement fingerprint (measure_key) without having to flatten the tree.