71 lines
1.9 KiB
Rust
71 lines
1.9 KiB
Rust
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//! Linear gradient builder & definition.
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use crate::gradient::{ColorStop, Gradient};
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use crate::{Color, Point};
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/// A linear gradient that can be used in the style of [`super::Fill`] or [`super::Stroke`].
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#[derive(Debug, Clone, PartialEq)]
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pub struct Linear {
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/// The point where the linear gradient begins.
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pub start: Point,
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/// The point where the linear gradient ends.
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pub end: Point,
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/// [`ColorStop`]s along the linear gradient path.
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pub color_stops: Vec<ColorStop>,
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}
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/// A [`Linear`] builder.
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#[derive(Debug)]
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pub struct Builder {
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start: Point,
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end: Point,
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stops: Vec<(f32, Color)>,
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valid: bool,
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}
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impl Builder {
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/// Creates a new [`Builder`].
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pub fn new(start: Point, end: Point) -> Self {
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Self {
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start,
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end,
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stops: vec![],
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valid: true,
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}
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}
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/// Adds a new stop, defined by an offset and a color, to the gradient.
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///
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/// `offset` must be between `0.0` and `1.0`.
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pub fn add_stop(mut self, offset: f32, color: Color) -> Self {
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if !(0.0..=1.0).contains(&offset) {
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self.valid = false;
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}
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self.stops.push((offset, color));
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self
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}
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/// Builds the linear [`Gradient`] of this [`Builder`].
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///
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/// Returns `None` if no stops were added to the builder or
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/// if stops not between 0.0 and 1.0 were added.
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pub fn build(self) -> Option<Gradient> {
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if self.stops.is_empty() || !self.valid {
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return None;
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}
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let mut stops: Vec<ColorStop> = self.stops.clone().into_iter().map(|f| ColorStop {
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offset: f.0,
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color: f.1
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}).collect();
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stops.sort_by(|a, b| a.offset.partial_cmp(&b.offset).unwrap());
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Some(Gradient::Linear(Linear {
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start: self.start,
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end: self.end,
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color_stops: stops
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}))
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}
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}
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