text: render text asynchronously

src/utils/on_drop_event.rs

@@ -0,0 +1,18 @@
+use {crate::utils::asyncevent::AsyncEvent, std::rc::Rc};
+
+#[derive(Default)]
+pub struct OnDropEvent {
+    ae: Rc<AsyncEvent>,
+}
+
+impl OnDropEvent {
+    pub fn event(&self) -> Rc<AsyncEvent> {
+        self.ae.clone()
+    }
+}
+
+impl Drop for OnDropEvent {
+    fn drop(&mut self) {
+        self.ae.trigger()
+    }
+}

src/utils/smallmap.rs

@@ -201,13 +201,20 @@ impl<K: Eq, V, const N: usize> SmallMapMut<K, V, N> {
     pub fn get_or_default_mut(&mut self, k: K) -> &mut V
     where
         V: Default,
+    {
+        self.get_or_insert_with(k, || V::default())
+    }
+
+    pub fn get_or_insert_with<F>(&mut self, k: K, f: F) -> &mut V
+    where
+        F: FnOnce() -> V,
     {
         for (ek, ev) in &mut self.m {
             if ek == &k {
                 return unsafe { (ev as *mut V).deref_mut() };
             }
         }
-        self.m.push((k, V::default()));
+        self.m.push((k, f()));
         &mut self.m.last_mut().unwrap().1
     }