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use super::{Color, Point};
use crate::properties::InterpolatedPropertyValue;
use crate::SharedVector;
#[cfg(not(feature = "std"))]
use num_traits::float::Float;
#[derive(Clone, PartialEq, Debug, derive_more::From)]
#[repr(C)]
#[non_exhaustive]
pub enum Brush {
SolidColor(Color),
LinearGradient(LinearGradientBrush),
}
impl Default for Brush {
fn default() -> Self {
Self::SolidColor(Color::default())
}
}
impl Brush {
pub fn color(&self) -> Color {
match self {
Brush::SolidColor(col) => *col,
Brush::LinearGradient(gradient) => {
gradient.stops().next().map(|stop| stop.color).unwrap_or_default()
}
}
}
pub fn is_transparent(&self) -> bool {
match self {
Brush::SolidColor(c) => c.alpha() == 0,
Brush::LinearGradient(_) => false,
}
}
}
#[derive(Clone, PartialEq, Debug)]
#[repr(transparent)]
pub struct LinearGradientBrush(SharedVector<GradientStop>);
impl LinearGradientBrush {
pub fn new(angle: f32, stops: impl IntoIterator<Item = GradientStop>) -> Self {
let stop_iter = stops.into_iter();
let mut encoded_angle_and_stops = SharedVector::with_capacity(stop_iter.size_hint().0 + 1);
encoded_angle_and_stops.push(GradientStop { color: Default::default(), position: angle });
encoded_angle_and_stops.extend(stop_iter);
Self(encoded_angle_and_stops)
}
pub fn angle(&self) -> f32 {
self.0[0].position
}
pub fn stops(&self) -> impl Iterator<Item = &GradientStop> {
self.0.iter().skip(1)
}
}
#[repr(C)]
#[derive(Copy, Clone, Debug, PartialEq)]
pub struct GradientStop {
pub color: Color,
pub position: f32,
}
pub fn line_for_angle(angle: f32) -> (Point, Point) {
let angle = angle.to_radians();
let r = (angle.sin().abs() + angle.cos().abs()) / 2.;
let (y, x) = (angle - core::f32::consts::PI / 2.).sin_cos();
let (y, x) = (y * r, x * r);
let start = Point::new(0.5 - x, 0.5 - y);
let end = Point::new(0.5 + x, 0.5 + y);
(start, end)
}
impl InterpolatedPropertyValue for Brush {
fn interpolate(&self, target_value: &Self, t: f32) -> Self {
match (self, target_value) {
(Brush::SolidColor(source_col), Brush::SolidColor(target_col)) => {
Brush::SolidColor(source_col.interpolate(target_col, t))
}
(Brush::SolidColor(col), Brush::LinearGradient(grad)) => {
let mut new_grad = grad.clone();
for x in new_grad.0.make_mut_slice().iter_mut().skip(1) {
x.color = col.interpolate(&x.color, t);
}
Brush::LinearGradient(new_grad)
}
(a @ Brush::LinearGradient(_), b @ Brush::SolidColor(_)) => {
Self::interpolate(b, a, 1. - t)
}
(Brush::LinearGradient(lhs), Brush::LinearGradient(rhs)) => {
if lhs.0.len() < rhs.0.len() {
Self::interpolate(target_value, self, 1. - t)
} else {
let mut new_grad = lhs.clone();
let mut iter = new_grad.0.make_mut_slice().iter_mut();
{
let angle = &mut iter.next().unwrap().position;
*angle = angle.interpolate(&rhs.angle(), t);
}
let mut rhs_stops = rhs.stops();
while let (Some(s1), Some(s2)) = (iter.next(), rhs_stops.next()) {
s1.color = s1.color.interpolate(&s2.color, t);
s1.position = s1.position.interpolate(&s2.position, t);
}
for x in iter {
x.position = x.position.interpolate(&1.0, t);
}
Brush::LinearGradient(new_grad)
}
}
}
}
}
#[test]
#[allow(clippy::float_cmp)]
fn test_linear_gradient_encoding() {
let stops: SharedVector<GradientStop> = [
GradientStop { position: 0.0, color: Color::from_argb_u8(255, 255, 0, 0) },
GradientStop { position: 0.5, color: Color::from_argb_u8(255, 0, 255, 0) },
GradientStop { position: 1.0, color: Color::from_argb_u8(255, 0, 0, 255) },
]
.into();
let grad = LinearGradientBrush::new(256., stops.clone());
assert_eq!(grad.angle(), 256.);
assert!(grad.stops().eq(stops.iter()));
}