lib8: implement layer blending

src/lib8.rs

@@ -2,6 +2,16 @@ use palette::encoding::srgb::Srgb;
 
 use rgb::RGB8;
 
+pub trait Rgb8Blend {
+    fn saturating_add(&self, b: Self) -> Self;
+}
+
+impl Rgb8Blend for RGB8 {
+    fn saturating_add(&self, b: Self) -> Self {
+        RGB8::new(self.r.saturating_add(b.r), self.g.saturating_add(b.g), self.b.saturating_add(b.b))
+    }
+}
+
 pub trait IntoRgb8 {
     fn into_rgb8(self) -> RGB8;
 }