Added support for gradients as background variants + other optimizations.

core/src/background.rs

@@ -1,11 +1,13 @@
-use crate::Color;
+use crate::{Color, Gradient};
 
 /// The background of some element.
 #[derive(Debug, Clone, Copy, PartialEq)]
 pub enum Background {
-    /// A solid color
+    /// A solid color.
     Color(Color),
-    // TODO: Add gradient and image variants
+    /// Linearly interpolate between several colors.
+    Gradient(Gradient),
+    // TODO: Add image variant
 }
 
 impl From<Color> for Background {
@@ -19,3 +21,9 @@ impl From<Color> for Option<Background> {
         Some(Background::from(color))
     }
 }
+
+impl From<Gradient> for Option<Background> {
+    fn from(gradient: Gradient) -> Self {
+        Some(Background::Gradient(gradient))
+    }
+}