Improve IME support with new Event::Ime (#4358)

* Closes #4354 

Fix: can't repeat input chinese words

AND

For Windows :
ImeEnable
ImeDisable

---------

Co-authored-by: Emil Ernerfeldt <emil.ernerfeldt@gmail.com>

Author: rustbasic

crates/eframe/src/web/text_agent.rs

@@ -68,7 +68,8 @@ pub fn install_text_agent(runner_ref: &WebRunner) -> Result<(), JsValue> {
                 is_composing.set(true);
                 input_clone.set_value("");
 
-                runner.input.raw.events.push(egui::Event::CompositionStart);
+                let egui_event = egui::Event::Ime(egui::ImeEvent::Enabled);
+                runner.input.raw.events.push(egui_event);
                 runner.needs_repaint.repaint_asap();
             }
         })?;
@@ -77,8 +78,9 @@ pub fn install_text_agent(runner_ref: &WebRunner) -> Result<(), JsValue> {
             &input,
             "compositionupdate",
             move |event: web_sys::CompositionEvent, runner: &mut AppRunner| {
-                if let Some(event) = event.data().map(egui::Event::CompositionUpdate) {
-                    runner.input.raw.events.push(event);
+                if let Some(text) = event.data() {
+                    let egui_event = egui::Event::Ime(egui::ImeEvent::Preedit(text));
+                    runner.input.raw.events.push(egui_event);
                     runner.needs_repaint.repaint_asap();
                 }
             },
@@ -91,8 +93,9 @@ pub fn install_text_agent(runner_ref: &WebRunner) -> Result<(), JsValue> {
                 is_composing.set(false);
                 input_clone.set_value("");
 
-                if let Some(event) = event.data().map(egui::Event::CompositionEnd) {
-                    runner.input.raw.events.push(event);
+                if let Some(text) = event.data() {
+                    let egui_event = egui::Event::Ime(egui::ImeEvent::Commit(text));
+                    runner.input.raw.events.push(egui_event);
                     runner.needs_repaint.repaint_asap();
                 }
             }

crates/egui-winit/src/lib.rs

@@ -95,7 +95,7 @@ pub struct State {
     pointer_touch_id: Option<u64>,
 
     /// track ime state
-    input_method_editor_started: bool,
+    has_sent_ime_enabled: bool,
 
     #[cfg(feature = "accesskit")]
     accesskit: Option<accesskit_winit::Adapter>,
@@ -136,7 +136,7 @@ impl State {
             simulate_touch_screen: false,
             pointer_touch_id: None,
 
-            input_method_editor_started: false,
+            has_sent_ime_enabled: false,
 
             #[cfg(feature = "accesskit")]
             accesskit: None,
@@ -342,23 +342,39 @@ impl State {
                 // We use input_method_editor_started to manually insert CompositionStart
                 // between Commits.
                 match ime {
-                    winit::event::Ime::Enabled | winit::event::Ime::Disabled => (),
-                    winit::event::Ime::Commit(text) => {
-                        self.input_method_editor_started = false;
+                    winit::event::Ime::Enabled => {
                         self.egui_input
                             .events
-                            .push(egui::Event::CompositionEnd(text.clone()));
+                            .push(egui::Event::Ime(egui::ImeEvent::Enabled));
+                        self.has_sent_ime_enabled = true;
                     }
-                    winit::event::Ime::Preedit(text, Some(_)) => {
-                        if !self.input_method_editor_started {
-                            self.input_method_editor_started = true;
-                            self.egui_input.events.push(egui::Event::CompositionStart);
+                    winit::event::Ime::Preedit(_, None) => {}
+                    winit::event::Ime::Preedit(text, Some(_cursor)) => {
+                        if !self.has_sent_ime_enabled {
+                            self.egui_input
+                                .events
+                                .push(egui::Event::Ime(egui::ImeEvent::Enabled));
+                            self.has_sent_ime_enabled = true;
                         }
                         self.egui_input
                             .events
-                            .push(egui::Event::CompositionUpdate(text.clone()));
+                            .push(egui::Event::Ime(egui::ImeEvent::Preedit(text.clone())));
+                    }
+                    winit::event::Ime::Commit(text) => {
+                        self.egui_input
+                            .events
+                            .push(egui::Event::Ime(egui::ImeEvent::Commit(text.clone())));
+                        self.egui_input
+                            .events
+                            .push(egui::Event::Ime(egui::ImeEvent::Disabled));
+                        self.has_sent_ime_enabled = false;
+                    }
+                    winit::event::Ime::Disabled => {
+                        self.egui_input
+                            .events
+                            .push(egui::Event::Ime(egui::ImeEvent::Disabled));
+                        self.has_sent_ime_enabled = false;
                     }
-                    winit::event::Ime::Preedit(_, None) => {}
                 };
 
                 EventResponse {
@@ -601,7 +617,8 @@ impl State {
         });
         // If we're not yet translating a touch or we're translating this very
         // touch …
-        if self.pointer_touch_id.is_none() || self.pointer_touch_id.unwrap() == touch.id {
+        if self.pointer_touch_id.is_none() || self.pointer_touch_id.unwrap_or_default() == touch.id
+        {
             // … emit PointerButton resp. PointerMoved events to emulate mouse
             match touch.phase {
                 winit::event::TouchPhase::Started => {
@@ -1531,7 +1548,7 @@ pub fn create_winit_window_builder<T>(
     // We set sizes and positions in egui:s own ui points, which depends on the egui
     // zoom_factor and the native pixels per point, so we need to know that here.
     // We don't know what monitor the window will appear on though, but
-    // we'll try to fix that after the window is created in the vall to `apply_viewport_builder_to_window`.
+    // we'll try to fix that after the window is created in the call to `apply_viewport_builder_to_window`.
     let native_pixels_per_point = event_loop
         .primary_monitor()
         .or_else(|| event_loop.available_monitors().next())

crates/egui/src/data/input.rs

@@ -445,14 +445,8 @@ pub enum Event {
     /// * `zoom > 1`: pinch spread
     Zoom(f32),
 
-    /// IME composition start.
-    CompositionStart,
-
-    /// A new IME candidate is being suggested.
-    CompositionUpdate(String),
-
-    /// IME composition ended with this final result.
-    CompositionEnd(String),
+    /// IME Event
+    Ime(ImeEvent),
 
     /// On touch screens, report this *in addition to*
     /// [`Self::PointerMoved`], [`Self::PointerButton`], [`Self::PointerGone`]
@@ -507,6 +501,25 @@ pub enum Event {
     },
 }
 
+/// IME event.
+///
+/// See <https://docs.rs/winit/latest/winit/event/enum.Ime.html>
+#[derive(Clone, Debug, Eq, PartialEq)]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+pub enum ImeEvent {
+    /// Notifies when the IME was enabled.
+    Enabled,
+
+    /// A new IME candidate is being suggested.
+    Preedit(String),
+
+    /// IME composition ended with this final result.
+    Commit(String),
+
+    /// Notifies when the IME was disabled.
+    Disabled,
+}
+
 /// Mouse button (or similar for touch input)
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
 #[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]

crates/egui/src/widgets/text_edit/builder.rs

@@ -950,47 +950,51 @@ fn events(
                 ..
             } => check_for_mutating_key_press(os, &mut cursor_range, text, galley, modifiers, *key),
 
-            Event::CompositionStart => {
-                state.has_ime = true;
-                None
-            }
-
-            Event::CompositionUpdate(text_mark) => {
-                // empty prediction can be produced when user press backspace
-                // or escape during ime. We should clear current text.
-                if text_mark != "\n" && text_mark != "\r" && state.has_ime {
-                    let mut ccursor = text.delete_selected(&cursor_range);
-                    let start_cursor = ccursor;
-                    if !text_mark.is_empty() {
-                        text.insert_text_at(&mut ccursor, text_mark, char_limit);
-                    }
+            Event::Ime(ime_event) => match ime_event {
+                ImeEvent::Enabled => {
+                    state.ime_enabled = true;
                     state.ime_cursor_range = cursor_range;
-                    Some(CCursorRange::two(start_cursor, ccursor))
-                } else {
                     None
                 }
-            }
-
-            Event::CompositionEnd(prediction) => {
-                // CompositionEnd only characters may be typed into TextEdit without trigger CompositionStart first,
-                // so do not check `state.has_ime = true` in the following statement.
-                if prediction != "\n" && prediction != "\r" {
-                    state.has_ime = false;
-                    let mut ccursor;
-                    if !prediction.is_empty()
-                        && cursor_range.secondary.ccursor.index
-                            == state.ime_cursor_range.secondary.ccursor.index
-                    {
-                        ccursor = text.delete_selected(&cursor_range);
-                        text.insert_text_at(&mut ccursor, prediction, char_limit);
+                ImeEvent::Preedit(text_mark) => {
+                    if text_mark == "\n" || text_mark == "\r" {
+                        None
+                    } else {
+                        // Empty prediction can be produced when user press backspace
+                        // or escape during IME, so we clear current text.
+                        let mut ccursor = text.delete_selected(&cursor_range);
+                        let start_cursor = ccursor;
+                        if !text_mark.is_empty() {
+                            text.insert_text_at(&mut ccursor, text_mark, char_limit);
+                        }
+                        state.ime_cursor_range = cursor_range;
+                        Some(CCursorRange::two(start_cursor, ccursor))
+                    }
+                }
+                ImeEvent::Commit(prediction) => {
+                    if prediction == "\n" || prediction == "\r" {
+                        None
                     } else {
-                        ccursor = cursor_range.primary.ccursor;
+                        state.ime_enabled = false;
+
+                        if !prediction.is_empty()
+                            && cursor_range.secondary.ccursor.index
+                                == state.ime_cursor_range.secondary.ccursor.index
+                        {
+                            let mut ccursor = text.delete_selected(&cursor_range);
+                            text.insert_text_at(&mut ccursor, prediction, char_limit);
+                            Some(CCursorRange::one(ccursor))
+                        } else {
+                            let ccursor = cursor_range.primary.ccursor;
+                            Some(CCursorRange::one(ccursor))
+                        }
                     }
-                    Some(CCursorRange::one(ccursor))
-                } else {
+                }
+                ImeEvent::Disabled => {
+                    state.ime_enabled = false;
                     None
                 }
-            }
+            },
 
             _ => None,
         };

crates/egui/src/widgets/text_edit/state.rs

@@ -42,7 +42,7 @@ pub struct TextEditState {
 
     // If IME candidate window is shown on this text edit.
     #[cfg_attr(feature = "serde", serde(skip))]
-    pub(crate) has_ime: bool,
+    pub(crate) ime_enabled: bool,
 
     // cursor range for IME candidate.
     #[cfg_attr(feature = "serde", serde(skip))]