Remove dependency on palette

src/euph/util.rs

@@ -1,12 +1,40 @@
 use crossterm::style::{Color, ContentStyle, Stylize};
-use palette::{FromColor, Hsl, RgbHue, Srgb};
+
+/// Convert HSL to RGB following [this approach from wikipedia][1].
+///
+/// `h` must be in the range `[0, 360]`, `s` and `l` in the range `[0, 1]`.
+///
+/// [1]: https://en.wikipedia.org/wiki/HSL_and_HSV#HSL_to_RGB
+fn hsl_to_rgb(h: f32, s: f32, l: f32) -> (u8, u8, u8) {
+    assert!((0.0..=360.0).contains(&h), "h must be in range [0, 360]");
+    assert!((0.0..=1.0).contains(&s), "s must be in range [0, 1]");
+    assert!((0.0..=1.0).contains(&l), "l must be in range [0, 1]");
+
+    let c = (1.0 - (2.0 * l - 1.0).abs()) * s;
+
+    let h_prime = h / 60.0;
+    let x = c * (1.0 - (h_prime.rem_euclid(2.0) - 1.0).abs());
+
+    let (r1, g1, b1) = match () {
+        _ if h_prime < 1.0 => (c, x, 0.0),
+        _ if h_prime < 2.0 => (x, c, 0.0),
+        _ if h_prime < 3.0 => (0.0, c, x),
+        _ if h_prime < 4.0 => (0.0, x, c),
+        _ if h_prime < 5.0 => (x, 0.0, c),
+        _ => (c, 0.0, x),
+    };
+
+    let m = l - c / 2.0;
+    let (r, g, b) = (r1 + m, g1 + m, b1 + m);
+
+    // The rgb values in the range [0,1] are each split into 256 segments of the
+    // same length, which are then assigned to the 256 possible values of an u8.
+    ((r * 256.0) as u8, (g * 256.0) as u8, (b * 256.0) as u8)
+}
 
 pub fn nick_color(nick: &str) -> (u8, u8, u8) {
-    let hue = RgbHue::from(euphoxide::nick_hue(nick) as f32);
-    let color = Hsl::new(hue, 1.0, 0.72);
-    Srgb::from_color(color)
-        .into_format::<u8>()
-        .into_components()
+    let hue = euphoxide::nick_hue(nick) as f32;
+    hsl_to_rgb(hue, 1.0, 0.72)
 }
 
 pub fn nick_style(nick: &str) -> ContentStyle {