Implement styling for Scrollable

style/src/scrollable.rs

@@ -0,0 +1,76 @@
+//! Navigate an endless amount of content with a scrollbar.
+use iced_core::{Background, Color};
+
+/// The appearance of a scrollable.
+#[derive(Debug, Clone, Copy)]
+pub struct Scrollbar {
+    pub background: Option<Background>,
+    pub border_radius: u16,
+    pub border_width: u16,
+    pub border_color: Color,
+    pub scroller: Scroller,
+}
+
+/// The appearance of the scroller of a scrollable.
+#[derive(Debug, Clone, Copy)]
+pub struct Scroller {
+    pub color: Color,
+    pub border_radius: u16,
+    pub border_width: u16,
+    pub border_color: Color,
+}
+
+/// A set of rules that dictate the style of a scrollable.
+pub trait StyleSheet {
+    /// Produces the style of an active scrollbar.
+    fn active(&self) -> Scrollbar;
+
+    /// Produces the style of an hovered scrollbar.
+    fn hovered(&self) -> Scrollbar;
+
+    /// Produces the style of a scrollbar that is being dragged.
+    fn dragging(&self) -> Scrollbar {
+        self.hovered()
+    }
+}
+
+struct Default;
+
+impl StyleSheet for Default {
+    fn active(&self) -> Scrollbar {
+        Scrollbar {
+            background: None,
+            border_radius: 5,
+            border_width: 0,
+            border_color: Color::TRANSPARENT,
+            scroller: Scroller {
+                color: [0.0, 0.0, 0.0, 0.7].into(),
+                border_radius: 5,
+                border_width: 0,
+                border_color: Color::TRANSPARENT,
+            },
+        }
+    }
+
+    fn hovered(&self) -> Scrollbar {
+        Scrollbar {
+            background: Some(Background::Color([0.0, 0.0, 0.0, 0.3].into())),
+            ..self.active()
+        }
+    }
+}
+
+impl std::default::Default for Box<dyn StyleSheet> {
+    fn default() -> Self {
+        Box::new(Default)
+    }
+}
+
+impl<T> From<T> for Box<dyn StyleSheet>
+where
+    T: 'static + StyleSheet,
+{
+    fn from(style: T) -> Self {
+        Box::new(style)
+    }
+}