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use super::*;
use crate::util::EcoString;
/// A decoration for a frame.
#[derive(Debug, Clone, Eq, PartialEq, Hash)]
pub enum Decoration {
/// A link to an external resource.
Link(EcoString),
/// An underline/strikethrough/overline decoration.
Line(LineDecoration),
}
impl Decoration {
/// Apply a decoration to a child's frame.
pub fn apply(&self, ctx: &LayoutContext, frame: &mut Frame) {
match self {
Decoration::Link(href) => {
let link = Element::Link(href.to_string(), frame.size);
frame.push(Point::zero(), link);
}
Decoration::Line(line) => {
line.apply(ctx, frame);
}
}
}
}
/// Defines a line that is positioned over, under or on top of text.
#[derive(Debug, Clone, Eq, PartialEq, Hash)]
pub struct LineDecoration {
/// The kind of line.
pub kind: LineKind,
/// Stroke color of the line, defaults to the text color if `None`.
pub stroke: Option<Paint>,
/// Thickness of the line's strokes (dependent on scaled font size), read
/// from the font tables if `None`.
pub thickness: Option<Linear>,
/// Position of the line relative to the baseline (dependent on scaled font
/// size), read from the font tables if `None`.
pub offset: Option<Linear>,
/// Amount that the line will be longer or shorter than its associated text
/// (dependent on scaled font size).
pub extent: Linear,
}
/// The kind of line decoration.
#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
pub enum LineKind {
/// A line under text.
Underline,
/// A line through text.
Strikethrough,
/// A line over text.
Overline,
}
impl LineDecoration {
/// Apply a line decoration to a all text elements in a frame.
pub fn apply(&self, ctx: &LayoutContext, frame: &mut Frame) {
for i in 0 .. frame.children.len() {
let (pos, child) = &frame.children[i];
if let FrameChild::Element(Element::Text(text)) = child {
let face = ctx.fonts.get(text.face_id);
let metrics = match self.kind {
LineKind::Underline => face.underline,
LineKind::Strikethrough => face.strikethrough,
LineKind::Overline => face.overline,
};
let stroke = self.stroke.unwrap_or(text.fill);
let thickness = self
.thickness
.map(|s| s.resolve(text.size))
.unwrap_or(metrics.strength.to_length(text.size));
let offset = self
.offset
.map(|s| s.resolve(text.size))
.unwrap_or(-metrics.position.to_length(text.size));
let extent = self.extent.resolve(text.size);
let subpos = Point::new(pos.x - extent, pos.y + offset);
let vector = Point::new(text.width + 2.0 * extent, Length::zero());
let line = Geometry::Line(vector, thickness);
frame.push(subpos, Element::Geometry(line, stroke));
}
}
}
}
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