Add an element to pane to take care of wiring initial mouse handlers

crates/gpui/src/elements/flex.rs

@@ -324,6 +324,7 @@ impl Element for Flex {
             // overall flex element and each child. We then align these points. So 0 would center
             // each child relative to the overall height/width of the flex. -1 puts children at
             // the start. 1 puts children at the end.
+            let aligned_child_origin = {
                 let cross_axis = self.axis.invert();
                 let my_center = bounds.size().along(cross_axis) / 2.;
                 let my_target = my_center + my_center * self.child_alignment;
@@ -339,6 +340,9 @@ impl Element for Flex {
                         .set_x(aligned_child_origin.x() - (child_target - my_target)),
                 }
 
+                aligned_child_origin
+            };
+
             child.paint(aligned_child_origin, visible_bounds, cx);
 
             match self.axis {

crates/welcome/src/welcome.rs

@@ -1,14 +1,13 @@
 use std::borrow::Cow;
 
 use gpui::{
-    elements::{Canvas, Empty, Flex, Image, Label, MouseEventHandler, ParentElement, Stack, Svg},
+    elements::{Empty, Flex, Image, Label, MouseEventHandler, ParentElement, Svg},
-    geometry::rect::RectF,
+    Action, Element, ElementBox, Entity, MouseButton, MutableAppContext, RenderContext,
-    Action, Element, ElementBox, Entity, MouseButton, MouseRegion, MutableAppContext,
+    Subscription, View, ViewContext,
-    RenderContext, Subscription, View, ViewContext,
 };
 use settings::{settings_file::SettingsFile, Settings, SettingsFileContent};
 use theme::CheckboxStyle;
-use workspace::{item::Item, Welcome, Workspace};
+use workspace::{item::Item, PaneBackdrop, Welcome, Workspace, WorkspaceId};
 
 pub fn init(cx: &mut MutableAppContext) {
     cx.add_action(|workspace: &mut Workspace, _: &Welcome, cx| {
@@ -43,30 +42,8 @@ impl View for WelcomePage {
         enum Metrics {}
         enum Diagnostics {}
 
-        let background = theme.editor.background;
+        PaneBackdrop::new(
-
+            self_handle.id(),
-        Stack::new()
-            .with_child(
-                // TODO: Can this be moved into the pane?
-                Canvas::new(move |bounds, visible_bounds, cx| {
-                    let visible_bounds = bounds.intersection(visible_bounds).unwrap_or_default();
-
-                    cx.paint_layer(Some(visible_bounds), |cx| {
-                        cx.scene.push_quad(gpui::Quad {
-                            bounds: RectF::new(bounds.origin(), bounds.size()),
-                            background: Some(background),
-                            ..Default::default()
-                        })
-                    });
-
-                    cx.scene.push_mouse_region(
-                        MouseRegion::new::<Self>(self_handle.id(), 0, visible_bounds)
-                            .on_down(gpui::MouseButton::Left, |_, cx| cx.focus_parent_view()),
-                    );
-                })
-                .boxed(),
-            )
-            .with_child(
             Flex::column()
                 .with_children([
                     Flex::row()
@@ -232,4 +209,11 @@ impl Item for WelcomePage {
     fn show_toolbar(&self) -> bool {
         false
     }
+    fn clone_on_split(
+        &self,
+        _workspace_id: WorkspaceId,
+        cx: &mut ViewContext<Self>,
+    ) -> Option<Self> {
+        Some(WelcomePage::new(cx))
+    }
 }

crates/workspace/src/pane.rs

@@ -24,8 +24,8 @@ use gpui::{
     keymap_matcher::KeymapContext,
     platform::{CursorStyle, NavigationDirection},
     Action, AnyViewHandle, AnyWeakViewHandle, AppContext, AsyncAppContext, Entity, EventContext,
-    ModelHandle, MouseButton, MutableAppContext, PromptLevel, Quad, RenderContext, Task, View,
+    ModelHandle, MouseButton, MouseRegion, MutableAppContext, PromptLevel, Quad, RenderContext,
-    ViewContext, ViewHandle, WeakViewHandle,
+    Task, View, ViewContext, ViewHandle, WeakViewHandle,
 };
 use project::{Project, ProjectEntryId, ProjectPath};
 use serde::Deserialize;
@@ -1706,6 +1706,93 @@ impl NavHistory {
     }
 }
 
+pub struct PaneBackdrop {
+    child_view: usize,
+    child: ElementBox,
+}
+impl PaneBackdrop {
+    pub fn new(pane_item_view: usize, child: ElementBox) -> Self {
+        PaneBackdrop {
+            child,
+            child_view: pane_item_view,
+        }
+    }
+}
+
+impl Element for PaneBackdrop {
+    type LayoutState = ();
+
+    type PaintState = ();
+
+    fn layout(
+        &mut self,
+        constraint: gpui::SizeConstraint,
+        cx: &mut gpui::LayoutContext,
+    ) -> (Vector2F, Self::LayoutState) {
+        let size = self.child.layout(constraint, cx);
+        (size, ())
+    }
+
+    fn paint(
+        &mut self,
+        bounds: RectF,
+        visible_bounds: RectF,
+        _: &mut Self::LayoutState,
+        cx: &mut gpui::PaintContext,
+    ) -> Self::PaintState {
+        let background = cx.global::<Settings>().theme.editor.background;
+
+        let visible_bounds = bounds.intersection(visible_bounds).unwrap_or_default();
+
+        cx.scene.push_quad(gpui::Quad {
+            bounds: RectF::new(bounds.origin(), bounds.size()),
+            background: Some(background),
+            ..Default::default()
+        });
+
+        let child_view_id = self.child_view;
+        cx.scene.push_mouse_region(
+            MouseRegion::new::<Self>(child_view_id, 0, visible_bounds).on_down(
+                gpui::MouseButton::Left,
+                move |_, cx| {
+                    let window_id = cx.window_id;
+                    cx.focus(window_id, Some(child_view_id))
+                },
+            ),
+        );
+
+        cx.paint_layer(Some(bounds), |cx| {
+            self.child.paint(bounds.origin(), visible_bounds, cx)
+        })
+    }
+
+    fn rect_for_text_range(
+        &self,
+        range_utf16: std::ops::Range<usize>,
+        _bounds: RectF,
+        _visible_bounds: RectF,
+        _layout: &Self::LayoutState,
+        _paint: &Self::PaintState,
+        cx: &gpui::MeasurementContext,
+    ) -> Option<RectF> {
+        self.child.rect_for_text_range(range_utf16, cx)
+    }
+
+    fn debug(
+        &self,
+        _bounds: RectF,
+        _layout: &Self::LayoutState,
+        _paint: &Self::PaintState,
+        cx: &gpui::DebugContext,
+    ) -> serde_json::Value {
+        gpui::json::json!({
+            "type": "Pane Back Drop",
+            "view": self.child_view,
+            "child": self.child.debug(cx),
+        })
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use std::sync::Arc;