Implement conversion between sRGB and sRGBA

src/image/srgb.rs

@@ -20,8 +20,45 @@ impl SRGBA {
         Self { r, g, b, a }
     }
 }
+
+impl Into<SRGB> for SRGBA {
+	fn into(self) -> SRGB {
+		SRGB::new(self.r, self.g, self.b)
+	}
+}
+
 impl SRGB {
     pub fn new(r: f32, g: f32, b: f32) -> Self {
         Self { r, g, b }
     }
 }
+
+impl Into<SRGBA> for SRGB {
+	fn into(self) -> SRGBA {
+		SRGBA::new(self.r, self.g, self.b, 1.0)
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+
+	#[test]
+	fn srgb_from_srgba_drops_alpha()
+	{
+		let srgb: SRGB = SRGBA::new(0.1, 0.2, 0.3, 0.4).into();
+		assert_eq!(srgb.r, 0.1);
+		assert_eq!(srgb.g, 0.2);
+		assert_eq!(srgb.b, 0.3);
+	}
+
+	#[test]
+	fn srgba_from_srgb_adds_alpha_1()
+	{
+		let srgba: SRGBA = SRGB::new(0.1, 0.2, 0.3).into();
+		assert_eq!(srgba.r, 0.1);
+		assert_eq!(srgba.g, 0.2);
+		assert_eq!(srgba.b, 0.3);
+		assert_eq!(srgba.a, 1.0);
+	}
+}