Move palettes to lib

plate-tool-lib/src/util.rs

@@ -30,6 +30,89 @@ pub fn num_to_letters(num: u8) -> Option<String> {
     Some(text.to_string())
 }
 
+//
+// Palettes moved from pt-web
+//
+
+// Sources:
+// https://iquilezles.org/articles/palettes/
+// http://dev.thi.ng/gradients/
+
+#[derive(Clone, Copy, PartialEq, Debug)]
+pub struct ColorPalette {
+    a: [f64; 3],
+    b: [f64; 3],
+    c: [f64; 3],
+    d: [f64; 3],
+}
+
+impl ColorPalette {
+    pub fn _new(a: [f64; 3], b: [f64; 3], c: [f64; 3], d: [f64; 3]) -> Self {
+        ColorPalette { a, b, c, d }
+    }
+
+    pub fn get(&self, t: f64) -> [f64; 3] {
+        [
+            (self.a[0] + self.b[0] * f64::cos(std::f64::consts::TAU * (self.c[0] * t + self.d[0])))
+                * 255.0,
+            (self.a[1] + self.b[1] * f64::cos(std::f64::consts::TAU * (self.c[1] * t + self.d[1])))
+                * 255.0,
+            (self.a[2] + self.b[2] * f64::cos(std::f64::consts::TAU * (self.c[2] * t + self.d[2])))
+                * 255.0,
+        ]
+    }
+
+    #[allow(dead_code)] // Preserve old implementation for reference
+    fn get_u8(&self, t: u8) -> [f64; 3] {
+        assert!(t > 0, "t must be greater than zero!");
+        self.get((2f64.powi(-(t.ilog2() as i32))) * (t as f64 + 0.5f64) - 1.0f64)
+    }
+
+    // pub fn get_uuid(&self, t: uuid::Uuid) -> [f64; 3] {
+    //     // self.get(t.as_u128() as f64 / (u128::MAX) as f64)
+    //     let mut r = SmallRng::seed_from_u64(t.as_u128() as u64);
+    //     self.get(r.gen_range(0.0..1.0f64))
+    // }
+
+    pub fn get_ordered(&self, t: uuid::Uuid, ordered_uuids: &[uuid::Uuid])
+        -> [f64; 3] {
+        let index = ordered_uuids.iter().position(|&x| x == t).expect("uuid must be in list of uuids") + 1;
+        self.get(Self::space_evenly(index))
+    }
+
+    pub fn get_linear(&self, t: f64, max: f64) -> [f64; 3] {
+        let scaled = t / max;
+        self.get(scaled)
+    }
+
+    fn space_evenly(x: usize) -> f64 {
+        let e: usize = (x.ilog2() + 1) as usize;
+        let d: usize = 2usize.pow(e as u32);
+        let n: usize = (2*x + 1) % d;
+        (n as f64) / (d as f64)
+    }
+}
+
+#[non_exhaustive]
+pub struct Palettes;
+
+#[allow(dead_code)]
+impl Palettes {
+    pub const RAINBOW: ColorPalette = ColorPalette {
+        a: [0.500, 0.500, 0.500],
+        b: [0.700, 0.700, 0.700],
+        c: [0.800, 0.800, 0.800],
+        d: [0.000, 0.333, 0.667],
+    };
+    pub const YELLOW_PINK: ColorPalette = ColorPalette {
+        a: [0.500, 0.500, 0.320],
+        b: [0.500, 0.500, 0.500],
+        c: [0.100, 0.500, 0.360],
+        d: [0.000, 0.000, 0.650],
+    };
+
+}
+
 #[cfg(test)]
 mod tests {
     use super::{letters_to_num, num_to_letters};