Take a target view when marking an element as draggable

crates/workspace/src/item.rs

@@ -54,12 +54,12 @@ pub trait Item: View {
     fn tab_description<'a>(&'a self, _: usize, _: &'a AppContext) -> Option<Cow<str>> {
         None
     }
-    fn tab_content(
+    fn tab_content<V: View>(
         &self,
         detail: Option<usize>,
         style: &theme::Tab,
         cx: &AppContext,
-    ) -> Element<Pane>;
+    ) -> Element<V>;
     fn for_each_project_item(&self, _: &AppContext, _: &mut dyn FnMut(usize, &dyn project::Item)) {}
     fn is_singleton(&self, _cx: &AppContext) -> bool {
         false
@@ -181,6 +181,12 @@ pub trait ItemHandle: 'static + fmt::Debug {
         style: &theme::Tab,
         cx: &AppContext,
     ) -> Element<Pane>;
+    fn dragged_tab_content(
+        &self,
+        detail: Option<usize>,
+        style: &theme::Tab,
+        cx: &AppContext,
+    ) -> Element<Workspace>;
     fn project_path(&self, cx: &AppContext) -> Option<ProjectPath>;
     fn project_entry_ids(&self, cx: &AppContext) -> SmallVec<[ProjectEntryId; 3]>;
     fn project_item_model_ids(&self, cx: &AppContext) -> SmallVec<[usize; 3]>;
@@ -281,6 +287,15 @@ impl<T: Item> ItemHandle for ViewHandle<T> {
         self.read(cx).tab_content(detail, style, cx)
     }
 
+    fn dragged_tab_content(
+        &self,
+        detail: Option<usize>,
+        style: &theme::Tab,
+        cx: &AppContext,
+    ) -> Element<Workspace> {
+        self.read(cx).tab_content(detail, style, cx)
+    }
+
     fn project_path(&self, cx: &AppContext) -> Option<ProjectPath> {
         let this = self.read(cx);
         let mut result = None;
@@ -927,12 +942,12 @@ pub(crate) mod test {
             })
         }
 
-        fn tab_content(
+        fn tab_content<V: View>(
             &self,
             detail: Option<usize>,
             _: &theme::Tab,
             _: &AppContext,
-        ) -> Element<Pane> {
+        ) -> Element<V> {
             self.tab_detail.set(detail);
             Empty::new().boxed()
         }

crates/workspace/src/pane.rs

@@ -1401,7 +1401,7 @@ impl Pane {
                             enum Tab {}
                             let mouse_event_handler =
                                 MouseEventHandler::<Tab, Pane>::new(ix, cx, |_, cx| {
-                                    Self::render_tab::<Pane>(
+                                    Self::render_tab(
                                         &item,
                                         pane.clone(),
                                         ix == 0,
@@ -1466,9 +1466,9 @@ impl Pane {
                             let theme = cx.global::<Settings>().theme.clone();
 
                             let detail = detail.clone();
-                            move |dragged_item: &DraggedItem, cx: &mut ViewContext<Pane>| {
+                            move |dragged_item: &DraggedItem, cx: &mut ViewContext<Workspace>| {
                                 let tab_style = &theme.workspace.tab_bar.dragged_tab;
-                                Self::render_tab::<Pane>(
+                                Self::render_dragged_tab(
                                     &dragged_item.item,
                                     dragged_item.pane.clone(),
                                     false,
@@ -1541,7 +1541,7 @@ impl Pane {
         tab_details
     }
 
-    fn render_tab<V: View>(
+    fn render_tab(
         item: &Box<dyn ItemHandle>,
         pane: WeakViewHandle<Pane>,
         first: bool,
@@ -1551,6 +1551,31 @@ impl Pane {
         cx: &mut ViewContext<Self>,
     ) -> Element<Self> {
         let title = item.tab_content(detail, &tab_style, cx);
+        Self::render_tab_with_title(title, item, pane, first, hovered, tab_style, cx)
+    }
+
+    fn render_dragged_tab(
+        item: &Box<dyn ItemHandle>,
+        pane: WeakViewHandle<Pane>,
+        first: bool,
+        detail: Option<usize>,
+        hovered: bool,
+        tab_style: &theme::Tab,
+        cx: &mut ViewContext<Workspace>,
+    ) -> Element<Workspace> {
+        let title = item.dragged_tab_content(detail, &tab_style, cx);
+        Self::render_tab_with_title(title, item, pane, first, hovered, tab_style, cx)
+    }
+
+    fn render_tab_with_title<T: View>(
+        title: Element<T>,
+        item: &Box<dyn ItemHandle>,
+        pane: WeakViewHandle<Pane>,
+        first: bool,
+        hovered: bool,
+        tab_style: &theme::Tab,
+        cx: &mut ViewContext<T>,
+    ) -> Element<T> {
         let mut container = tab_style.container.clone();
         if first {
             container.border.left = false;

crates/workspace/src/shared_screen.rs

@@ -1,6 +1,6 @@
 use crate::{
     item::{Item, ItemEvent},
-    ItemNavHistory, Pane, WorkspaceId,
+    ItemNavHistory, WorkspaceId,
 };
 use anyhow::Result;
 use call::participant::{Frame, RemoteVideoTrack};
@@ -106,12 +106,12 @@ impl Item for SharedScreen {
         }
     }
 
-    fn tab_content(
+    fn tab_content<V: View>(
         &self,
         _: Option<usize>,
         style: &theme::Tab,
         _: &AppContext,
-    ) -> gpui::Element<Pane> {
+    ) -> gpui::Element<V> {
         Flex::row()
             .with_child(
                 Svg::new("icons/disable_screen_sharing_12.svg")