1#![allow(dead_code)]
2
3use bytemuck::{Pod, Zeroable};
4use serde::de::{self, Deserialize, Deserializer, Visitor};
5use std::fmt;
6use std::num::ParseIntError;
7
8pub fn rgb(hex: u32) -> Rgba {
9 let r = ((hex >> 16) & 0xFF) as f32 / 255.0;
10 let g = ((hex >> 8) & 0xFF) as f32 / 255.0;
11 let b = (hex & 0xFF) as f32 / 255.0;
12 Rgba { r, g, b, a: 1.0 }.into()
13}
14
15#[derive(Clone, Copy, Default, Debug)]
16pub struct Rgba {
17 pub r: f32,
18 pub g: f32,
19 pub b: f32,
20 pub a: f32,
21}
22
23impl Rgba {
24 pub fn blend(&self, other: Rgba) -> Self {
25 if other.a >= 1.0 {
26 return other;
27 } else if other.a <= 0.0 {
28 return *self;
29 } else {
30 return Rgba {
31 r: (self.r * (1.0 - other.a)) + (other.r * other.a),
32 g: (self.g * (1.0 - other.a)) + (other.g * other.a),
33 b: (self.b * (1.0 - other.a)) + (other.b * other.a),
34 a: self.a,
35 };
36 }
37 }
38}
39
40struct RgbaVisitor;
41
42impl<'de> Visitor<'de> for RgbaVisitor {
43 type Value = Rgba;
44
45 fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
46 formatter.write_str("a string in the format #rrggbb or #rrggbbaa")
47 }
48
49 fn visit_str<E: de::Error>(self, value: &str) -> Result<Rgba, E> {
50 if value.len() == 7 || value.len() == 9 {
51 let r = u8::from_str_radix(&value[1..3], 16).unwrap() as f32 / 255.0;
52 let g = u8::from_str_radix(&value[3..5], 16).unwrap() as f32 / 255.0;
53 let b = u8::from_str_radix(&value[5..7], 16).unwrap() as f32 / 255.0;
54 let a = if value.len() == 9 {
55 u8::from_str_radix(&value[7..9], 16).unwrap() as f32 / 255.0
56 } else {
57 1.0
58 };
59 Ok(Rgba { r, g, b, a })
60 } else {
61 Err(E::custom(
62 "Bad format for RGBA. Expected #rrggbb or #rrggbbaa.",
63 ))
64 }
65 }
66}
67
68impl<'de> Deserialize<'de> for Rgba {
69 fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
70 deserializer.deserialize_str(RgbaVisitor)
71 }
72}
73
74impl From<Hsla> for Rgba {
75 fn from(color: Hsla) -> Self {
76 let h = color.h;
77 let s = color.s;
78 let l = color.l;
79
80 let c = (1.0 - (2.0 * l - 1.0).abs()) * s;
81 let x = c * (1.0 - ((h * 6.0) % 2.0 - 1.0).abs());
82 let m = l - c / 2.0;
83 let cm = c + m;
84 let xm = x + m;
85
86 let (r, g, b) = match (h * 6.0).floor() as i32 {
87 0 | 6 => (cm, xm, m),
88 1 => (xm, cm, m),
89 2 => (m, cm, xm),
90 3 => (m, xm, cm),
91 4 => (xm, m, cm),
92 _ => (cm, m, xm),
93 };
94
95 Rgba {
96 r,
97 g,
98 b,
99 a: color.a,
100 }
101 }
102}
103
104impl TryFrom<&'_ str> for Rgba {
105 type Error = ParseIntError;
106
107 fn try_from(value: &'_ str) -> Result<Self, Self::Error> {
108 let r = u8::from_str_radix(&value[1..3], 16)? as f32 / 255.0;
109 let g = u8::from_str_radix(&value[3..5], 16)? as f32 / 255.0;
110 let b = u8::from_str_radix(&value[5..7], 16)? as f32 / 255.0;
111 let a = if value.len() > 7 {
112 u8::from_str_radix(&value[7..9], 16)? as f32 / 255.0
113 } else {
114 1.0
115 };
116
117 Ok(Rgba { r, g, b, a })
118 }
119}
120
121#[derive(Default, Copy, Clone, Debug, PartialEq, Zeroable, Pod)]
122#[repr(C)]
123pub struct Hsla {
124 pub h: f32,
125 pub s: f32,
126 pub l: f32,
127 pub a: f32,
128}
129
130impl Eq for Hsla {}
131
132pub fn hsla(h: f32, s: f32, l: f32, a: f32) -> Hsla {
133 Hsla {
134 h: h.clamp(0., 1.),
135 s: s.clamp(0., 1.),
136 l: l.clamp(0., 1.),
137 a: a.clamp(0., 1.),
138 }
139}
140
141pub fn black() -> Hsla {
142 Hsla {
143 h: 0.,
144 s: 0.,
145 l: 0.,
146 a: 1.,
147 }
148}
149
150impl Hsla {
151 /// Returns true if the HSLA color is fully transparent, false otherwise.
152 pub fn is_transparent(&self) -> bool {
153 self.a == 0.0
154 }
155
156 /// Blends `other` on top of `self` based on `other`'s alpha value. The resulting color is a combination of `self`'s and `other`'s colors.
157 ///
158 /// If `other`'s alpha value is 1.0 or greater, `other` color is fully opaque, thus `other` is returned as the output color.
159 /// If `other`'s alpha value is 0.0 or less, `other` color is fully transparent, thus `self` is returned as the output color.
160 /// Else, the output color is calculated as a blend of `self` and `other` based on their weighted alpha values.
161 ///
162 /// Assumptions:
163 /// - Alpha values are contained in the range [0, 1], with 1 as fully opaque and 0 as fully transparent.
164 /// - The relative contributions of `self` and `other` is based on `self`'s alpha value (`self.a`) and `other`'s alpha value (`other.a`), `self` contributing `self.a * (1.0 - other.a)` and `other` contributing it's own alpha value.
165 /// - RGB color components are contained in the range [0, 1].
166 /// - If `self` and `other` colors are out of the valid range, the blend operation's output and behavior is undefined.
167 pub fn blend(self, other: Hsla) -> Hsla {
168 let alpha = other.a;
169
170 if alpha >= 1.0 {
171 return other;
172 } else if alpha <= 0.0 {
173 return self;
174 } else {
175 let converted_self = Rgba::from(self);
176 let converted_other = Rgba::from(other);
177 let blended_rgb = converted_self.blend(converted_other);
178 return Hsla::from(blended_rgb);
179 }
180 }
181
182 /// Fade out the color by a given factor. This factor should be between 0.0 and 1.0.
183 /// Where 0.0 will leave the color unchanged, and 1.0 will completely fade out the color.
184 pub fn fade_out(&mut self, factor: f32) {
185 self.a *= 1.0 - factor.clamp(0., 1.);
186 }
187}
188
189impl From<Rgba> for Hsla {
190 fn from(color: Rgba) -> Self {
191 let r = color.r;
192 let g = color.g;
193 let b = color.b;
194
195 let max = r.max(g.max(b));
196 let min = r.min(g.min(b));
197 let delta = max - min;
198
199 let l = (max + min) / 2.0;
200 let s = if l == 0.0 || l == 1.0 {
201 0.0
202 } else if l < 0.5 {
203 delta / (2.0 * l)
204 } else {
205 delta / (2.0 - 2.0 * l)
206 };
207
208 let h = if delta == 0.0 {
209 0.0
210 } else if max == r {
211 ((g - b) / delta).rem_euclid(6.0) / 6.0
212 } else if max == g {
213 ((b - r) / delta + 2.0) / 6.0
214 } else {
215 ((r - g) / delta + 4.0) / 6.0
216 };
217
218 Hsla {
219 h,
220 s,
221 l,
222 a: color.a,
223 }
224 }
225}
226
227impl<'de> Deserialize<'de> for Hsla {
228 fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
229 where
230 D: Deserializer<'de>,
231 {
232 // First, deserialize it into Rgba
233 let rgba = Rgba::deserialize(deserializer)?;
234
235 // Then, use the From<Rgba> for Hsla implementation to convert it
236 Ok(Hsla::from(rgba))
237 }
238}