iced: propagate pane drag destinations

widget/src/pane_grid.rs

@@ -90,6 +90,7 @@ use crate::core::{
     self, Background, Border, Clipboard, Color, Element, Event, Layout, Length,
     Pixels, Point, Rectangle, Shell, Size, Theme, Vector, Widget,
 };
+use log::trace;
 
 const DRAG_DEADBAND_DISTANCE: f32 = 10.0;
 const THICKNESS_RATIO: f32 = 25.0;
@@ -1030,6 +1031,35 @@ where
 
         (!children.is_empty()).then(|| Group::with_children(children).overlay())
     }
+
+    fn drag_destinations(
+        &self,
+        state: &Tree,
+        layout: Layout<'_>,
+        renderer: &Renderer,
+        dnd_rectangles: &mut crate::core::clipboard::DndDestinationRectangles,
+    ) {
+        self.contents
+            .iter()
+            .zip(state.children.iter())
+            .zip(layout.children())
+            .for_each(|((content, tree), child_layout)| {
+                trace!(
+                    target: "iced::widget::pane_grid",
+                    "pane drag layout bounds=({:.2},{:.2},{:.2},{:.2})",
+                    child_layout.bounds().x,
+                    child_layout.bounds().y,
+                    child_layout.bounds().width,
+                    child_layout.bounds().height
+                );
+                content.drag_destinations(
+                    tree,
+                    child_layout.with_virtual_offset(layout.virtual_offset()),
+                    renderer,
+                    dnd_rectangles,
+                );
+            });
+    }
 }
 
 impl<'a, Message, Theme, Renderer> From<PaneGrid<'a, Message, Theme, Renderer>>

widget/src/pane_grid/content.rs

@@ -6,7 +6,7 @@ use crate::core::renderer;
 use crate::core::widget::{self, Tree};
 use crate::core::{
     self, Clipboard, Element, Event, Layout, Point, Rectangle, Shell, Size,
-    Vector,
+    Vector, event,
 };
 use crate::pane_grid::{Draggable, TitleBar};
 
@@ -308,6 +308,51 @@ where
         None
     }
 
+    pub(crate) fn drag_destinations(
+        &self,
+        tree: &Tree,
+        layout: Layout<'_>,
+        renderer: &Renderer,
+        dnd_rectangles: &mut core::clipboard::DndDestinationRectangles,
+    ) {
+        let mut body_layout = layout;
+        if self.title_bar.is_some() {
+            let mut children = layout.children();
+            let title_bar_layout = children.next();
+            body_layout = children.next().unwrap_or(layout);
+            if let Some(title_bar_layout) = title_bar_layout {
+                log::trace!(
+                    target: "iced::widget::pane_grid::content",
+                    "title_bar bounds=({:.2},{:.2},{:.2},{:.2}) body_bounds=({:.2},{:.2},{:.2},{:.2})",
+                    title_bar_layout.bounds().x,
+                    title_bar_layout.bounds().y,
+                    title_bar_layout.bounds().width,
+                    title_bar_layout.bounds().height,
+                    body_layout.bounds().x,
+                    body_layout.bounds().y,
+                    body_layout.bounds().width,
+                    body_layout.bounds().height,
+                );
+            }
+        } else {
+            log::trace!(
+                target: "iced::widget::pane_grid::content",
+                "body_bounds=({:.2},{:.2},{:.2},{:.2})",
+                body_layout.bounds().x,
+                body_layout.bounds().y,
+                body_layout.bounds().width,
+                body_layout.bounds().height,
+            );
+        }
+
+        self.body.as_widget().drag_destinations(
+            &tree.children[0],
+            body_layout,
+            renderer,
+            dnd_rectangles,
+        );
+    }
+
     pub(crate) fn mouse_interaction(
         &self,
         tree: &Tree,