Draft Panes widget and panes example

wgpu/src/renderer/widget.rs

@@ -2,6 +2,7 @@ mod button;
 mod checkbox;
 mod column;
 mod container;
+mod panes;
 mod progress_bar;
 mod radio;
 mod row;

wgpu/src/renderer/widget/panes.rs

@@ -0,0 +1,34 @@
+use crate::{Primitive, Renderer};
+use iced_native::{panes, Element, Layout, MouseCursor, Point};
+
+impl panes::Renderer for Renderer {
+    fn draw<Message>(
+        &mut self,
+        defaults: &Self::Defaults,
+        content: &[Element<'_, Message, Self>],
+        layout: Layout<'_>,
+        cursor_position: Point,
+    ) -> Self::Output {
+        let mut mouse_cursor = MouseCursor::OutOfBounds;
+
+        (
+            Primitive::Group {
+                primitives: content
+                    .iter()
+                    .zip(layout.children())
+                    .map(|(child, layout)| {
+                        let (primitive, new_mouse_cursor) =
+                            child.draw(self, defaults, layout, cursor_position);
+
+                        if new_mouse_cursor > mouse_cursor {
+                            mouse_cursor = new_mouse_cursor;
+                        }
+
+                        primitive
+                    })
+                    .collect(),
+            },
+            mouse_cursor,
+        )
+    }
+}