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use crate::{
color::Color,
visitor::{Visit, VisitResult, Visitor},
};
use std::cmp::Ordering;
#[derive(Debug)]
pub struct GradientPoint {
location: f32,
color: Color,
}
impl Visit for GradientPoint {
fn visit(&mut self, name: &str, visitor: &mut Visitor) -> VisitResult {
visitor.enter_region(name)?;
self.location.visit("Location", visitor)?;
self.color.visit("Color", visitor)?;
visitor.leave_region()
}
}
impl GradientPoint {
pub fn new(location: f32, color: Color) -> Self {
Self { location, color }
}
}
impl Default for GradientPoint {
fn default() -> Self {
Self {
location: 0.0,
color: Color::default(),
}
}
}
impl Clone for GradientPoint {
fn clone(&self) -> Self {
Self {
location: self.location,
color: self.color,
}
}
}
#[derive(Debug)]
pub struct ColorGradient {
points: Vec<GradientPoint>,
}
impl Clone for ColorGradient {
fn clone(&self) -> Self {
Self {
points: self.points.clone(),
}
}
}
impl Visit for ColorGradient {
fn visit(&mut self, name: &str, visitor: &mut Visitor) -> VisitResult {
visitor.enter_region(name)?;
self.points.visit("Points", visitor)?;
visitor.leave_region()
}
}
impl Default for ColorGradient {
fn default() -> Self {
Self::new()
}
}
impl ColorGradient {
pub fn new() -> Self {
Self { points: Vec::new() }
}
pub fn add_point(&mut self, pt: GradientPoint) {
self.points.push(pt);
self.points.sort_by(|a, b| {
a.location
.partial_cmp(&b.location)
.unwrap_or(Ordering::Equal)
});
}
pub fn get_color(&self, location: f32) -> Color {
if self.points.is_empty() {
return Color::WHITE;
} else if self.points.len() == 1 {
return self.points.first().unwrap().color;
} else if self.points.len() == 2 {
let pt_a = self.points.get(0).unwrap();
let pt_b = self.points.get(1).unwrap();
if location >= pt_a.location && location <= pt_b.location {
let span = pt_b.location - pt_a.location;
let t = (location - pt_a.location) / span;
return pt_a.color.lerp(pt_b.color, t);
} else if location < pt_a.location {
return pt_a.color;
} else {
return pt_b.color;
}
}
let first = self.points.first().unwrap();
let last = self.points.last().unwrap();
if location <= first.location {
first.color
} else if location >= last.location {
last.color
} else {
let mut pt_a_index = 0;
for (i, pt) in self.points.iter().enumerate() {
if location >= pt.location {
pt_a_index = i;
}
}
let pt_b_index = pt_a_index + 1;
let pt_a = self.points.get(pt_a_index).unwrap();
let pt_b = self.points.get(pt_b_index).unwrap();
let span = pt_b.location - pt_a.location;
let t = (location - pt_a.location) / span;
pt_a.color.lerp(pt_b.color, t)
}
}
pub fn clear(&mut self) {
self.points.clear()
}
}
#[derive(Default)]
pub struct ColorGradientBuilder {
points: Vec<GradientPoint>,
}
impl ColorGradientBuilder {
pub fn new() -> Self {
Self {
points: Default::default(),
}
}
pub fn with_point(mut self, point: GradientPoint) -> Self {
self.points.push(point);
self
}
pub fn build(mut self) -> ColorGradient {
self.points.sort_by(|a, b| {
a.location
.partial_cmp(&b.location)
.unwrap_or(Ordering::Equal)
});
ColorGradient {
points: self.points,
}
}
}