spans now good (other than direction) + refactor

src/layout/color.rs

@@ -0,0 +1,51 @@
+#![allow(clippy::multiple_bound_locations)]
+
+#[repr(C)]
+#[derive(Clone, Copy, bytemuck::Zeroable)]
+pub struct Color<T: ColorNum> {
+    r: T,
+    g: T,
+    b: T,
+    a: T,
+}
+
+impl<T: ColorNum> Color<T> {
+    pub const BLACK: Self = Self::rgb(T::MIN, T::MIN, T::MIN);
+    pub const WHITE: Self = Self::rgb(T::MAX, T::MAX, T::MAX);
+
+    pub const RED: Self = Self::rgb(T::MAX, T::MIN, T::MIN);
+    pub const ORANGE: Self = Self::rgb(T::MAX, T::MID, T::MIN);
+    pub const YELLOW: Self = Self::rgb(T::MAX, T::MAX, T::MIN);
+    pub const LIME: Self = Self::rgb(T::MID, T::MAX, T::MIN);
+    pub const GREEN: Self = Self::rgb(T::MIN, T::MAX, T::MIN);
+    pub const CYAN: Self = Self::rgb(T::MIN, T::MAX, T::MAX);
+    pub const BLUE: Self = Self::rgb(T::MIN, T::MIN, T::MAX);
+    pub const MAGENTA: Self = Self::rgb(T::MAX, T::MIN, T::MAX);
+}
+
+impl<T: ColorNum> Color<T> {
+    pub const fn new(r: T, g: T, b: T, a: T) -> Self {
+        Self { r, g, b, a }
+    }
+    pub const fn rgb(r: T, g: T, b: T) -> Self {
+        Self { r, g, b, a: T::MAX }
+    }
+    pub fn alpha(mut self, a: T) -> Self {
+        self.a = a;
+        self
+    }
+}
+
+pub trait ColorNum {
+    const MIN: Self;
+    const MID: Self;
+    const MAX: Self;
+}
+
+impl ColorNum for u8 {
+    const MIN: Self = u8::MIN;
+    const MID: Self = u8::MAX / 2;
+    const MAX: Self = u8::MAX;
+}
+
+unsafe impl bytemuck::Pod for Color<u8> {}