iris: move text state into shared resources

app/src/ui/composer.rs

@@ -6,8 +6,7 @@ const APPROX_LINE_HEIGHT_DP: f32 = 24.0;
 const FIELD_PAD_DP: f32 = 12.0;
 
 /// `field` is exposed so the caller can read its content on submit
-/// (`field.edit(rsc).text()`) and clear it afterward
-/// (`field.edit(rsc).set("")`).
+/// (`field(rsc).text()`) and clear it afterward (`field(rsc).set("")`).
 pub struct Composer {
     pub field: WeakWidget<TextEdit>,
     /// The bar's own outer padding -- only `bottom` is ever changed, by

app/src/ui/mod.rs

@@ -532,6 +532,24 @@ mod apply_tests {
         out
     }
 
+    #[test]
+    fn registering_a_font_after_drawing_invalidates_its_text_owner() {
+        let mut rsc = TestRsc {
+            ui: Ui::default(),
+            events: EventManager::default(),
+        };
+        rsc.ui.resize((800.0, 600.0));
+        let root = wtext("already shaped").add_strong(&mut rsc).any();
+        rsc.draw(&root);
+        assert!(!rsc.widgets().has_updates());
+
+        rsc.ui.register_font("late-icons", ICON_FONT).unwrap();
+
+        assert!(rsc.widgets().has_updates());
+        rsc.draw(&root);
+        assert!(!rsc.widgets().has_updates());
+    }
+
     fn cost_of_one_delta(paragraphs: usize) -> (u64, u64) {
         let mut rsc = TestRsc {
             ui: Ui::default(),