From fc44a59a6f8fe3b6405ef2e7aa56f1b4774327f6 Mon Sep 17 00:00:00 2001
From: Joscha <joscha@plugh.de>
Date: Fri, 19 Aug 2022 22:50:39 +0200
Subject: [PATCH] Remove dependency on palette

---
 Cargo.lock       | 60 ------------------------------------------------
 Cargo.toml       |  1 -
 src/euph/util.rs | 40 +++++++++++++++++++++++++++-----
 3 files changed, 34 insertions(+), 67 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index a200efa..7368637 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -28,15 +28,6 @@ version = "1.0.61"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "508b352bb5c066aac251f6daf6b36eccd03e8a88e8081cd44959ea277a3af9a8"
 
-[[package]]
-name = "approx"
-version = "0.5.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cab112f0a86d568ea0e627cc1d6be74a1e9cd55214684db5561995f6dad897c6"
-dependencies = [
- "num-traits",
-]
-
 [[package]]
 name = "async-trait"
 version = "0.1.57"
@@ -194,7 +185,6 @@ dependencies = [
  "edit",
  "euphoxide",
  "log",
- "palette",
  "parking_lot",
  "rusqlite",
  "serde_json",
@@ -333,15 +323,6 @@ dependencies = [
  "instant",
 ]
 
-[[package]]
-name = "find-crate"
-version = "0.6.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "59a98bbaacea1c0eb6a0876280051b892eb73594fd90cf3b20e9c817029c57d2"
-dependencies = [
- "toml",
-]
-
 [[package]]
 name = "fnv"
 version = "1.0.7"
@@ -629,15 +610,6 @@ dependencies = [
  "windows-sys",
 ]
 
-[[package]]
-name = "num-traits"
-version = "0.2.15"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "578ede34cf02f8924ab9447f50c28075b4d3e5b269972345e7e0372b38c6cdcd"
-dependencies = [
- "autocfg",
-]
-
 [[package]]
 name = "num_cpus"
 version = "1.13.1"
@@ -675,29 +647,6 @@ version = "6.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "648001efe5d5c0102d8cea768e348da85d90af8ba91f0bea908f157951493cd4"
 
-[[package]]
-name = "palette"
-version = "0.6.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8f9cd68f7112581033f157e56c77ac4a5538ec5836a2e39284e65bd7d7275e49"
-dependencies = [
- "approx",
- "num-traits",
- "palette_derive",
-]
-
-[[package]]
-name = "palette_derive"
-version = "0.6.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "05eedf46a8e7c27f74af0c9cfcdb004ceca158cb1b918c6f68f8d7a549b3e427"
-dependencies = [
- "find-crate",
- "proc-macro2",
- "quote",
- "syn",
-]
-
 [[package]]
 name = "parking_lot"
 version = "0.12.1"
@@ -1249,15 +1198,6 @@ dependencies = [
  "webpki",
 ]
 
-[[package]]
-name = "toml"
-version = "0.5.9"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8d82e1a7758622a465f8cee077614c73484dac5b836c02ff6a40d5d1010324d7"
-dependencies = [
- "serde",
-]
-
 [[package]]
 name = "toss"
 version = "0.1.0"
diff --git a/Cargo.toml b/Cargo.toml
index d736dfc..a3ea11d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -12,7 +12,6 @@ crossterm = "0.25.0"
 directories = "4.0.1"
 edit = "0.1.4"
 log = { version = "0.4.17", features = ["std"] }
-palette = { version = "0.6.1", default-features = false, features = ["std"] }
 parking_lot = "0.12.1"
 rusqlite = { version = "0.28.0", features = ["bundled", "time"] }
 serde_json = "1.0.83"
diff --git a/src/euph/util.rs b/src/euph/util.rs
index 1ec7bb3..05eb467 100644
--- a/src/euph/util.rs
+++ b/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 {