Tooltips in mouse event handler & fix executor timer

Co-Authored-By: Conrad Irwin <conrad@zed.dev>

crates/ui2/src/components/tooltip.rs

@@ -1,20 +1,44 @@
+use std::time::Duration;
+
 use gpui2::{
-    div, px, Div, ParentElement, Render, SharedString, Styled, View, ViewContext, VisualContext,
+    div, px, Component, Div, ParentElement, Render, SharedString, Styled, View, ViewContext,
+    VisualContext, WindowContext,
 };
 use theme2::ActiveTheme;
 
+const DELAY: Duration = Duration::from_millis(500);
+
 #[derive(Clone, Debug)]
 pub struct TextTooltip {
     title: SharedString,
+    visible: bool,
 }
 
 impl TextTooltip {
     pub fn new(str: SharedString) -> Self {
-        Self { title: str }
+        Self {
+            title: str,
+            visible: false,
+        }
     }
 
-    pub fn build_view<C: VisualContext>(str: SharedString, cx: &mut C) -> C::Result<View<Self>> {
-        cx.build_view(|cx| TextTooltip::new(str))
+    pub fn build_view(str: SharedString, cx: &mut WindowContext) -> View<Self> {
+        let view = cx.build_view(|cx| TextTooltip::new(str));
+
+        let handle = view.downgrade();
+        cx.spawn(|mut cx| async move {
+            cx.background_executor().timer(DELAY).await;
+
+            handle
+                .update(&mut cx, |this, cx| {
+                    this.visible = true;
+                    cx.notify();
+                })
+                .ok();
+        })
+        .detach();
+
+        view
     }
 }
 
@@ -24,9 +48,11 @@ impl Render for TextTooltip {
     fn render(&mut self, cx: &mut ViewContext<Self>) -> Self::Element {
         let theme = cx.theme();
         div()
+            .when(!self.visible, |this| this.invisible())
             .bg(theme.colors().background)
             .rounded(px(8.))
             .border()
+            .font("Zed Sans")
             .border_color(theme.colors().border)
             .text_color(theme.colors().text)
             .pl_2()