refactor: move some code around to make place for new Layout

emigui/src/containers/popup.rs

@@ -0,0 +1,27 @@
+use std::sync::Arc;
+
+use crate::*;
+
+pub fn show_tooltip(ctx: &Arc<Context>, add_contents: impl FnOnce(&mut Ui)) {
+    if let Some(mouse_pos) = ctx.input().mouse_pos {
+        //  TODO: default size
+        let id = Id::tooltip();
+        let window_pos = mouse_pos + vec2(16.0, 16.0);
+        show_popup(ctx, id, window_pos, add_contents);
+    }
+}
+
+/// Show a pop-over window
+pub fn show_popup(
+    ctx: &Arc<Context>,
+    id: Id,
+    window_pos: Pos2,
+    add_contents: impl FnOnce(&mut Ui),
+) -> InteractInfo {
+    use containers::*;
+    Area::new(id)
+        .order(Order::Foreground)
+        .fixed_pos(window_pos)
+        .interactable(false)
+        .show(ctx, |ui| Frame::popup(&ctx.style()).show(ui, add_contents))
+}