Implement split highlight on hover for PaneGrid

graphics/src/widget/pane_grid.rs

@@ -8,16 +8,19 @@
 //!
 //! [`pane_grid` example]: https://github.com/hecrj/iced/tree/0.2/examples/pane_grid
 use crate::defaults;
-use crate::{Backend, Primitive, Renderer};
+use crate::{Backend, Color, Primitive, Renderer};
+use iced_native::container;
 use iced_native::mouse;
 use iced_native::pane_grid;
 use iced_native::{Element, Layout, Point, Rectangle, Vector};
 
 pub use iced_native::pane_grid::{
-    Axis, Configuration, Content, Direction, DragEvent, Pane, ResizeEvent,
-    Split, State, TitleBar,
+    Axis, Configuration, Content, Direction, DragEvent, Node, Pane,
+    ResizeEvent, Split, State, TitleBar,
 };
 
+pub use iced_style::pane_grid::{Line, StyleSheet};
+
 /// A collection of panes distributed using either vertical or horizontal splits
 /// to completely fill the space available.
 ///
@@ -31,13 +34,16 @@ impl<B> pane_grid::Renderer for Renderer<B>
 where
     B: Backend,
 {
+    type Style = Box<dyn StyleSheet>;
+
     fn draw<Message>(
         &mut self,
         defaults: &Self::Defaults,
         content: &[(Pane, Content<'_, Message, Self>)],
         dragging: Option<(Pane, Point)>,
-        resizing: Option<Axis>,
+        resizing: Option<(Axis, Rectangle, bool)>,
         layout: Layout<'_>,
+        style_sheet: &<Self as pane_grid::Renderer>::Style,
         cursor_position: Point,
     ) -> Self::Output {
         let pane_cursor_position = if dragging.is_some() {
@@ -73,7 +79,8 @@ where
             })
             .collect();
 
-        let primitives = if let Some((index, layout, origin)) = dragged_pane {
+        let mut primitives = if let Some((index, layout, origin)) = dragged_pane
+        {
             let pane = panes.remove(index);
             let bounds = layout.bounds();
 
@@ -103,15 +110,62 @@ where
             panes
         };
 
+        let (primitives, mouse_interaction) =
+            if let Some((axis, split_region, is_picked)) = resizing {
+                let highlight = if is_picked {
+                    style_sheet.picked_split()
+                } else {
+                    style_sheet.hovered_split()
+                };
+
+                if let Some(highlight) = highlight {
+                    primitives.push(Primitive::Quad {
+                        bounds: match axis {
+                            Axis::Horizontal => Rectangle {
+                                x: split_region.x,
+                                y: (split_region.y
+                                    + (split_region.height - highlight.width)
+                                        / 2.0)
+                                    .round(),
+                                width: split_region.width,
+                                height: highlight.width,
+                            },
+                            Axis::Vertical => Rectangle {
+                                x: (split_region.x
+                                    + (split_region.width - highlight.width)
+                                        / 2.0)
+                                    .round(),
+                                y: split_region.y,
+                                width: highlight.width,
+                                height: split_region.height,
+                            },
+                        },
+                        background: highlight.color.into(),
+                        border_radius: 0.0,
+                        border_width: 0.0,
+                        border_color: Color::TRANSPARENT,
+                    });
+                }
+
+                (
+                    primitives,
+                    match axis {
+                        Axis::Horizontal => {
+                            mouse::Interaction::ResizingVertically
+                        }
+                        Axis::Vertical => {
+                            mouse::Interaction::ResizingHorizontally
+                        }
+                    },
+                )
+            } else {
+                (primitives, mouse_interaction)
+            };
+
         (
             Primitive::Group { primitives },
             if dragging.is_some() {
                 mouse::Interaction::Grabbing
-            } else if let Some(axis) = resizing {
-                match axis {
-                    Axis::Horizontal => mouse::Interaction::ResizingVertically,
-                    Axis::Vertical => mouse::Interaction::ResizingHorizontally,
-                }
             } else {
                 mouse_interaction
             },
@@ -122,7 +176,7 @@ where
         &mut self,
         defaults: &Self::Defaults,
         bounds: Rectangle,
-        style_sheet: &Self::Style,
+        style_sheet: &<Self as container::Renderer>::Style,
         title_bar: Option<(&TitleBar<'_, Message, Self>, Layout<'_>)>,
         body: (&Element<'_, Message, Self>, Layout<'_>),
         cursor_position: Point,
@@ -182,7 +236,7 @@ where
         &mut self,
         defaults: &Self::Defaults,
         bounds: Rectangle,
-        style_sheet: &Self::Style,
+        style_sheet: &<Self as container::Renderer>::Style,
         content: (&Element<'_, Message, Self>, Layout<'_>),
         controls: Option<(&Element<'_, Message, Self>, Layout<'_>)>,
         cursor_position: Point,