Re-add IME support

masonry/src/passes/update.rs

@@ -6,12 +6,13 @@ use std::collections::HashSet;
 use cursor_icon::CursorIcon;
 use tracing::{info_span, trace};
 
-use crate::passes::event::run_on_pointer_event_pass;
+use crate::passes::event::{run_on_pointer_event_pass, run_on_text_event_pass};
 use crate::passes::{enter_span, enter_span_if, merge_state_up, recurse_on_children};
 use crate::render_root::{RenderRoot, RenderRootSignal, RenderRootState};
 use crate::tree_arena::ArenaMut;
 use crate::{
-    PointerEvent, QueryCtx, RegisterCtx, Update, UpdateCtx, Widget, WidgetId, WidgetState,
+    PointerEvent, QueryCtx, RegisterCtx, TextEvent, Update, UpdateCtx, Widget, WidgetId,
+    WidgetState,
 };
 
 // --- MARK: HELPERS ---
@@ -402,6 +403,19 @@ pub(crate) fn run_update_focus_pass(root: &mut RenderRoot) {
     }
 
     let prev_focused = root.global_state.focused_widget;
+    let was_ime_active = root.global_state.is_ime_active;
+
+    let synthesize_ime_disabled =
+        was_ime_active && prev_focused != root.global_state.next_focused_widget;
+    if synthesize_ime_disabled {
+        // IME was active, but the next focused widget is going to receive the
+        // Ime::Disabled event. Synthesize an Ime::Disabled event here and send it to
+        // the widget about to be unfocused.
+        run_on_text_event_pass(root, &TextEvent::Ime(winit::event::Ime::Disabled));
+    }
+
+    // Note: handling of the Ime::Disabled event sent above may have changed the next focused
+    // widget.
     let next_focused = root.global_state.next_focused_widget;
 
     // "Focused path" means the focused widget, and all its parents.
@@ -458,8 +472,10 @@ pub(crate) fn run_update_focus_pass(root: &mut RenderRoot) {
         }
     }
 
-    if prev_focused != next_focused {
-        let was_ime_active = root.global_state.is_ime_active;
+    // Refocus if the focused widget changed. Or, if the focused widget was going to change, the
+    // handling of the synthesized Ime::Disabled event above may have changed the focus back to the
+    // original widget. In that case, also refocus. This is messy.
+    if prev_focused != next_focused || synthesize_ime_disabled {
         let is_ime_active = if let Some(id) = next_focused {
             root.widget_arena.get_state(id).item.accepts_text_input
         } else {
@@ -501,7 +517,7 @@ pub(crate) fn run_update_focus_pass(root: &mut RenderRoot) {
         }
     }
 
-    root.global_state.focused_widget = root.global_state.next_focused_widget;
+    root.global_state.focused_widget = next_focused;
     root.global_state.focused_path = next_focused_path;
 }