Create colours module with colour definitions

src/colours.rs

@@ -0,0 +1,21 @@
+use crate::*;
+
+macro_rules! hex {
+	( $value:literal ) => {
+		image::SRGBA {
+			r: (($value >> 16) & 0xff) as f32 / 255.0,
+			g: (($value >> 8) & 0xff) as f32 / 255.0,
+			b: ($value & 0xff) as f32 / 255.0,
+			a: 1.0,
+		}
+	}
+}
+
+pub const BLACK: image::SRGBA = hex!(0x000000);
+pub const RED: image::SRGBA = hex!(0xff0000);
+pub const GREEN: image::SRGBA = hex!(0x00ff00);
+pub const BLUE: image::SRGBA = hex!(0x0000ff);
+pub const CYAN: image::SRGBA = hex!(0x00ffff);
+pub const MAGENTA: image::SRGBA = hex!(0xff00ff);
+pub const YELLOW: image::SRGBA = hex!(0xffff00);
+pub const WHITE: image::SRGBA = hex!(0xffffff);

src/lib.rs

@@ -1,3 +1,4 @@
+pub mod colours;
 pub mod contour;
 pub mod draw;
 pub mod filter;