Merge pull request #2793 from rhysd/issue-2792

Fix the initial candidate window position

8 files changed, 127 insertions, 116 deletions

diff --git a/core/src/input_method.rs b/core/src/input_method.rs
index 9c83b083..cd8d459d 100644
--- a/core/src/input_method.rs
+++ b/core/src/input_method.rs
@@ -6,14 +6,10 @@ use std::ops::Range;
 /// The input method strategy of a widget.
 #[derive(Debug, Clone, PartialEq)]
 pub enum InputMethod<T = String> {
-    /// No input method strategy has been specified.
-    None,
-    /// No input method is allowed.
+    /// Input method is disabled.
     Disabled,
-    /// Input methods are allowed, but not open yet.
-    Allowed,
-    /// Input method is open.
-    Open {
+    /// Input method is enabled.
+    Enabled {
         /// The position at which the input method dialog should be placed.
         position: Point,
         /// The [`Purpose`] of the input method.
@@ -91,13 +87,13 @@ impl InputMethod {
     /// # use iced_core::input_method::{InputMethod, Purpose, Preedit};
     /// # use iced_core::Point;
     ///
-    /// let open = InputMethod::Open {
+    /// let open = InputMethod::Enabled {
     ///     position: Point::ORIGIN,
     ///     purpose: Purpose::Normal,
     ///     preedit: Some(Preedit { content: "1".to_owned(), selection: None, text_size: None }),
     /// };
     ///
-    /// let open_2 = InputMethod::Open {
+    /// let open_2 = InputMethod::Enabled {
     ///     position: Point::ORIGIN,
     ///     purpose: Purpose::Secure,
     ///     preedit: Some(Preedit { content: "2".to_owned(), selection: None, text_size: None }),
@@ -105,12 +101,6 @@ impl InputMethod {
     ///
     /// let mut ime = InputMethod::Disabled;
     ///
-    /// ime.merge(&InputMethod::<String>::Allowed);
-    /// assert_eq!(ime, InputMethod::Allowed);
-    ///
-    /// ime.merge(&InputMethod::<String>::Disabled);
-    /// assert_eq!(ime, InputMethod::Allowed);
-    ///
     /// ime.merge(&open);
     /// assert_eq!(ime, open);
     ///
@@ -118,22 +108,16 @@ impl InputMethod {
     /// assert_eq!(ime, open);
     /// ```
     pub fn merge<T: AsRef<str>>(&mut self, other: &InputMethod<T>) {
-        match (&self, other) {
-            (InputMethod::Open { .. }, _)
-            | (
-                InputMethod::Allowed,
-                InputMethod::None | InputMethod::Disabled,
-            )
-            | (InputMethod::Disabled, InputMethod::None) => {}
-            _ => {
-                *self = other.to_owned();
-            }
+        if let InputMethod::Enabled { .. } = self {
+            return;
         }
+
+        *self = other.to_owned();
     }
 
     /// Returns true if the [`InputMethod`] is open.
-    pub fn is_open(&self) -> bool {
-        matches!(self, Self::Open { .. })
+    pub fn is_enabled(&self) -> bool {
+        matches!(self, Self::Enabled { .. })
     }
 }
 
@@ -144,14 +128,12 @@ impl<T> InputMethod<T> {
         T: AsRef<str>,
     {
         match self {
-            Self::None => InputMethod::None,
             Self::Disabled => InputMethod::Disabled,
-            Self::Allowed => InputMethod::Allowed,
-            Self::Open {
+            Self::Enabled {
                 position,
                 purpose,
                 preedit,
-            } => InputMethod::Open {
+            } => InputMethod::Enabled {
                 position: *position,
                 purpose: *purpose,
                 preedit: preedit.as_ref().map(Preedit::to_owned),
diff --git a/core/src/shell.rs b/core/src/shell.rs
index 509e3822..56250e2e 100644
--- a/core/src/shell.rs
+++ b/core/src/shell.rs
@@ -27,7 +27,7 @@ impl<'a, Message> Shell<'a, Message> {
             redraw_request: window::RedrawRequest::Wait,
             is_layout_invalid: false,
             are_widgets_invalid: false,
-            input_method: InputMethod::None,
+            input_method: InputMethod::Disabled,
         }
     }
 
diff --git a/graphics/src/text/editor.rs b/graphics/src/text/editor.rs
index c73d189c..765de07e 100644
--- a/graphics/src/text/editor.rs
+++ b/graphics/src/text/editor.rs
@@ -11,7 +11,7 @@ use cosmic_text::Edit as _;
 
 use std::borrow::Cow;
 use std::fmt;
-use std::sync::{self, Arc};
+use std::sync::{self, Arc, RwLock};
 
 /// A multi-line text editor.
 #[derive(Debug, PartialEq)]
@@ -19,6 +19,7 @@ pub struct Editor(Option<Arc<Internal>>);
 
 struct Internal {
     editor: cosmic_text::Editor<'static>,
+    cursor: RwLock<Option<Cursor>>,
     font: Font,
     bounds: Size,
     topmost_line_changed: Option<usize>,
@@ -114,10 +115,14 @@ impl editor::Editor for Editor {
     fn cursor(&self) -> editor::Cursor {
         let internal = self.internal();
 
+        if let Ok(Some(cursor)) = internal.cursor.read().as_deref() {
+            return cursor.clone();
+        }
+
         let cursor = internal.editor.cursor();
         let buffer = buffer_from_editor(&internal.editor);
 
-        match internal.editor.selection_bounds() {
+        let cursor = match internal.editor.selection_bounds() {
             Some((start, end)) => {
                 let line_height = buffer.metrics().line_height;
                 let selected_lines = end.line - start.line + 1;
@@ -237,7 +242,12 @@ impl editor::Editor for Editor {
                         - buffer.scroll().vertical,
                 ))
             }
-        }
+        };
+
+        *internal.cursor.write().expect("Write to cursor cache") =
+            Some(cursor.clone());
+
+        cursor
     }
 
     fn cursor_position(&self) -> (usize, usize) {
@@ -259,6 +269,13 @@ impl editor::Editor for Editor {
 
         let editor = &mut internal.editor;
 
+        // Clear cursor cache
+        let _ = internal
+            .cursor
+            .write()
+            .expect("Write to cursor cache")
+            .take();
+
         match action {
             // Motion events
             Action::Move(motion) => {
@@ -527,6 +544,13 @@ impl editor::Editor for Editor {
 
         internal.editor.shape_as_needed(font_system.raw(), false);
 
+        // Clear cursor cache
+        let _ = internal
+            .cursor
+            .write()
+            .expect("Write to cursor cache")
+            .take();
+
         self.0 = Some(Arc::new(internal));
     }
 
@@ -635,6 +659,7 @@ impl Default for Internal {
                     line_height: 1.0,
                 },
             )),
+            cursor: RwLock::new(None),
             font: Font::default(),
             bounds: Size::ZERO,
             topmost_line_changed: None,
diff --git a/runtime/src/user_interface.rs b/runtime/src/user_interface.rs
index cb441678..9b396c69 100644
--- a/runtime/src/user_interface.rs
+++ b/runtime/src/user_interface.rs
@@ -189,7 +189,7 @@ where
 
         let mut outdated = false;
         let mut redraw_request = window::RedrawRequest::Wait;
-        let mut input_method = InputMethod::None;
+        let mut input_method = InputMethod::Disabled;
 
         let mut manual_overlay = ManuallyDrop::new(
             self.root
diff --git a/widget/src/scrollable.rs b/widget/src/scrollable.rs
index fe71fd6b..0cf75c04 100644
--- a/widget/src/scrollable.rs
+++ b/widget/src/scrollable.rs
@@ -729,7 +729,7 @@ where
                     _ => mouse::Cursor::Unavailable,
                 };
 
-                let had_input_method = shell.input_method().is_open();
+                let had_input_method = shell.input_method().is_enabled();
 
                 let translation =
                     state.translation(self.direction, bounds, content_bounds);
@@ -750,7 +750,7 @@ where
                 );
 
                 if !had_input_method {
-                    if let InputMethod::Open { position, .. } =
+                    if let InputMethod::Enabled { position, .. } =
                         shell.input_method_mut()
                     {
                         *position = *position - translation;
diff --git a/widget/src/text_editor.rs b/widget/src/text_editor.rs
index ce5da9ef..7e40a56a 100644
--- a/widget/src/text_editor.rs
+++ b/widget/src/text_editor.rs
@@ -339,10 +339,6 @@ where
             return InputMethod::Disabled;
         };
 
-        let Some(preedit) = &state.preedit else {
-            return InputMethod::Allowed;
-        };
-
         let bounds = layout.bounds();
         let internal = self.content.0.borrow_mut();
 
@@ -363,10 +359,10 @@ where
         let position =
             cursor + translation + Vector::new(0.0, f32::from(line_height));
 
-        InputMethod::Open {
+        InputMethod::Enabled {
             position,
             purpose: input_method::Purpose::Normal,
-            preedit: Some(preedit.as_ref()),
+            preedit: state.preedit.as_ref().map(input_method::Preedit::as_ref),
         }
     }
 }
diff --git a/widget/src/text_input.rs b/widget/src/text_input.rs
index bb2685bd..ae3dfe4c 100644
--- a/widget/src/text_input.rs
+++ b/widget/src/text_input.rs
@@ -406,10 +406,6 @@ where
             return InputMethod::Disabled;
         };
 
-        let Some(preedit) = &state.is_ime_open else {
-            return InputMethod::Allowed;
-        };
-
         let secure_value = self.is_secure.then(|| value.secure());
         let value = secure_value.as_ref().unwrap_or(value);
 
@@ -433,14 +429,14 @@ where
         let x = (text_bounds.x + cursor_x).floor() - scroll_offset
             + alignment_offset;
 
-        InputMethod::Open {
+        InputMethod::Enabled {
             position: Point::new(x, text_bounds.y + text_bounds.height),
             purpose: if self.is_secure {
                 input_method::Purpose::Secure
             } else {
                 input_method::Purpose::Normal
             },
-            preedit: Some(preedit.as_ref()),
+            preedit: state.preedit.as_ref().map(input_method::Preedit::as_ref),
         }
     }
 
@@ -584,7 +580,7 @@ where
         let draw = |renderer: &mut Renderer, viewport| {
             let paragraph = if text.is_empty()
                 && state
-                    .is_ime_open
+                    .preedit
                     .as_ref()
                     .map(|preedit| preedit.content.is_empty())
                     .unwrap_or(true)
@@ -1260,7 +1256,7 @@ where
                 input_method::Event::Opened | input_method::Event::Closed => {
                     let state = state::<Renderer>(tree);
 
-                    state.is_ime_open =
+                    state.preedit =
                         matches!(event, input_method::Event::Opened)
                             .then(input_method::Preedit::new);
 
@@ -1270,7 +1266,7 @@ where
                     let state = state::<Renderer>(tree);
 
                     if state.is_focused.is_some() {
-                        state.is_ime_open = Some(input_method::Preedit {
+                        state.preedit = Some(input_method::Preedit {
                             content: content.to_owned(),
                             selection: selection.clone(),
                             text_size: self.size,
@@ -1323,23 +1319,30 @@ where
                 let state = state::<Renderer>(tree);
 
                 if let Some(focus) = &mut state.is_focused {
-                    if focus.is_window_focused
-                        && matches!(
+                    if focus.is_window_focused {
+                        if matches!(
                             state.cursor.state(&self.value),
                             cursor::State::Index(_)
-                        )
-                    {
-                        focus.now = *now;
-
-                        let millis_until_redraw = CURSOR_BLINK_INTERVAL_MILLIS
-                            - (*now - focus.updated_at).as_millis()
-                                % CURSOR_BLINK_INTERVAL_MILLIS;
-
-                        shell.request_redraw_at(
-                            *now + Duration::from_millis(
-                                millis_until_redraw as u64,
-                            ),
-                        );
+                        ) {
+                            focus.now = *now;
+
+                            let millis_until_redraw =
+                                CURSOR_BLINK_INTERVAL_MILLIS
+                                    - (*now - focus.updated_at).as_millis()
+                                        % CURSOR_BLINK_INTERVAL_MILLIS;
+
+                            shell.request_redraw_at(
+                                *now + Duration::from_millis(
+                                    millis_until_redraw as u64,
+                                ),
+                            );
+                        }
+
+                        shell.request_input_method(&self.input_method(
+                            state,
+                            layout,
+                            &self.value,
+                        ));
                     }
                 }
             }
@@ -1363,12 +1366,6 @@ where
 
         if let Event::Window(window::Event::RedrawRequested(_now)) = event {
             self.last_status = Some(status);
-
-            shell.request_input_method(&self.input_method(
-                state,
-                layout,
-                &self.value,
-            ));
         } else if self
             .last_status
             .is_some_and(|last_status| status != last_status)
@@ -1528,9 +1525,9 @@ pub struct State<P: text::Paragraph> {
     placeholder: paragraph::Plain<P>,
     icon: paragraph::Plain<P>,
     is_focused: Option<Focus>,
-    is_ime_open: Option<input_method::Preedit>,
     is_dragging: bool,
     is_pasting: Option<Value>,
+    preedit: Option<input_method::Preedit>,
     last_click: Option<mouse::Click>,
     cursor: Cursor,
     keyboard_modifiers: keyboard::Modifiers,
diff --git a/winit/src/program/window_manager.rs b/winit/src/program/window_manager.rs
index d5b334df..27306439 100644
--- a/winit/src/program/window_manager.rs
+++ b/winit/src/program/window_manager.rs
@@ -75,6 +75,7 @@ where
                 mouse_interaction: mouse::Interaction::None,
                 redraw_at: None,
                 preedit: None,
+                ime_state: None,
             },
         );
 
@@ -166,6 +167,7 @@ where
     pub renderer: P::Renderer,
     pub redraw_at: Option<Instant>,
     preedit: Option<Preedit<P::Renderer>>,
+    ime_state: Option<(Point, input_method::Purpose)>,
 }
 
 impl<P, C> Window<P, C>
@@ -206,52 +208,36 @@ where
 
     pub fn request_input_method(&mut self, input_method: InputMethod) {
         match input_method {
-            InputMethod::None => {}
             InputMethod::Disabled => {
-                self.raw.set_ime_allowed(false);
+                self.disable_ime();
             }
-            InputMethod::Allowed | InputMethod::Open { .. } => {
-                self.raw.set_ime_allowed(true);
-            }
-        }
-
-        if let InputMethod::Open {
-            position,
-            purpose,
-            preedit,
-        } = input_method
-        {
-            self.raw.set_ime_cursor_area(
-                LogicalPosition::new(position.x, position.y),
-                LogicalSize::new(10, 10), // TODO?
-            );
-
-            self.raw.set_ime_purpose(conversion::ime_purpose(purpose));
-
-            if let Some(preedit) = preedit {
-                if preedit.content.is_empty() {
-                    self.preedit = None;
-                } else if let Some(overlay) = &mut self.preedit {
-                    overlay.update(
-                        position,
-                        &preedit,
-                        self.state.background_color(),
-                        &self.renderer,
-                    );
+            InputMethod::Enabled {
+                position,
+                purpose,
+                preedit,
+            } => {
+                self.enable_ime(position, purpose);
+
+                if let Some(preedit) = preedit {
+                    if preedit.content.is_empty() {
+                        self.preedit = None;
+                    } else {
+                        let mut overlay =
+                            self.preedit.take().unwrap_or_else(Preedit::new);
+
+                        overlay.update(
+                            position,
+                            &preedit,
+                            self.state.background_color(),
+                            &self.renderer,
+                        );
+
+                        self.preedit = Some(overlay);
+                    }
                 } else {
-                    let mut overlay = Preedit::new();
-                    overlay.update(
-                        position,
-                        &preedit,
-                        self.state.background_color(),
-                        &self.renderer,
-                    );
-
-                    self.preedit = Some(overlay);
+                    self.preedit = None;
                 }
             }
-        } else {
-            self.preedit = None;
         }
     }
 
@@ -268,6 +254,31 @@ where
             );
         }
     }
+
+    fn enable_ime(&mut self, position: Point, purpose: input_method::Purpose) {
+        if self.ime_state.is_none() {
+            self.raw.set_ime_allowed(true);
+        }
+
+        if self.ime_state != Some((position, purpose)) {
+            self.raw.set_ime_cursor_area(
+                LogicalPosition::new(position.x, position.y),
+                LogicalSize::new(10, 10), // TODO?
+            );
+            self.raw.set_ime_purpose(conversion::ime_purpose(purpose));
+
+            self.ime_state = Some((position, purpose));
+        }
+    }
+
+    fn disable_ime(&mut self) {
+        if self.ime_state.is_some() {
+            self.raw.set_ime_allowed(false);
+            self.ime_state = None;
+        }
+
+        self.preedit = None;
+    }
 }
 
 struct Preedit<Renderer>