88 lines
2.6 KiB
Rust
88 lines
2.6 KiB
Rust
//! A gradient that can be used as a [`Fill`] for some geometry.
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//!
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//! For a gradient that you can use as a background variant for a widget, see [`Gradient`].
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//!
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//! [`Gradient`]: crate::core::Gradient;
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use crate::core::gradient::ColorStop;
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use crate::core::{Color, Point};
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use std::cmp::Ordering;
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#[derive(Debug, Clone, PartialEq)]
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/// A fill which linearly interpolates colors along a direction.
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///
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/// For a gradient which can be used as a fill for a background of a widget, see [`crate::core::Gradient`].
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pub enum Gradient {
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/// A linear gradient interpolates colors along a direction from its `start` to its `end`
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/// point.
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Linear(Linear),
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}
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impl From<Linear> for Gradient {
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fn from(gradient: Linear) -> Self {
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Self::Linear(gradient)
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}
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}
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/// A linear gradient that can be used in the style of [`Fill`] or [`Stroke`].
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///
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/// [`Fill`]: crate::geometry::Fill;
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/// [`Stroke`]: crate::geometry::Stroke;
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#[derive(Debug, Clone, Copy, PartialEq)]
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pub struct Linear {
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/// The absolute starting position of the gradient.
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pub start: Point,
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/// The absolute ending position of the gradient.
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pub end: Point,
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/// [`ColorStop`]s along the linear gradient direction.
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pub stops: [Option<ColorStop>; 8],
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}
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impl Linear {
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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: [None; 8],
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}
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}
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/// Adds a new [`ColorStop`], defined by an offset and a color, to the gradient.
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///
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/// Any `offset` that is not within `0.0..=1.0` will be silently ignored.
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///
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/// Any stop added after the 8th will be silently ignored.
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pub fn add_stop(mut self, offset: f32, color: Color) -> Self {
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if offset.is_finite() && (0.0..=1.0).contains(&offset) {
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let (Ok(index) | Err(index)) =
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self.stops.binary_search_by(|stop| match stop {
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None => Ordering::Greater,
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Some(stop) => stop.offset.partial_cmp(&offset).unwrap(),
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});
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if index < 8 {
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self.stops[index] = Some(ColorStop { offset, color });
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}
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} else {
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log::warn!("Gradient: ColorStop must be within 0.0..=1.0 range.");
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};
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self
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}
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/// Adds multiple [`ColorStop`]s to the gradient.
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///
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/// Any stop added after the 8th will be silently ignored.
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pub fn add_stops(
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mut self,
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stops: impl IntoIterator<Item = ColorStop>,
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) -> Self {
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for stop in stops.into_iter() {
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self = self.add_stop(stop.offset, stop.color)
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}
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self
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}
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}
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