Implement split highlight on hover for PaneGrid

style/src/lib.rs

@@ -10,6 +10,7 @@ pub mod button;
 pub mod checkbox;
 pub mod container;
 pub mod menu;
+pub mod pane_grid;
 pub mod pick_list;
 pub mod progress_bar;
 pub mod radio;

style/src/pane_grid.rs

@@ -0,0 +1,51 @@
+//! Let your users split regions of your application and organize layout
+//! dynamically.
+use iced_core::Color;
+
+/// A set of rules that dictate the style of a container.
+pub trait StyleSheet {
+    /// The [`Line`] to draw when a split is picked.
+    fn picked_split(&self) -> Option<Line>;
+
+    /// The [`Line`] to draw when a split is hovered.
+    fn hovered_split(&self) -> Option<Line>;
+}
+
+/// A line.
+///
+/// It is normally used to define the highlight of something, like a split.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct Line {
+    /// The [`Color`] of the [`Line`].
+    pub color: Color,
+
+    /// The width of the [`Line`].
+    pub width: f32,
+}
+
+struct Default;
+
+impl StyleSheet for Default {
+    fn picked_split(&self) -> Option<Line> {
+        None
+    }
+
+    fn hovered_split(&self) -> Option<Line> {
+        None
+    }
+}
+
+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)
+    }
+}