Draft input_method support

core/src/event.rs

@@ -1,4 +1,5 @@
 //! Handle events of a user interface.
+use crate::input_method;
 use crate::keyboard;
 use crate::mouse;
 use crate::touch;
@@ -23,6 +24,9 @@ pub enum Event {
 
     /// A touch event
     Touch(touch::Event),
+
+    /// A input method event
+    InputMethod(input_method::Event),
 }
 
 /// The status of an [`Event`] after being processed.

core/src/input_method.rs

@@ -0,0 +1,24 @@
+//! Listen to input method events.
+
+/// A input method event.
+///
+/// _**Note:** This type is largely incomplete! If you need to track
+/// additional events, feel free to [open an issue] and share your use case!_
+///
+/// [open an issue]: https://github.com/iced-rs/iced/issues
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum Event {
+    // These events correspond to underlying winit ime events.
+    // https://docs.rs/winit/latest/winit/event/enum.Ime.html
+    /// the IME was enabled.
+    Enabled,
+
+    /// new composing text should be set at the cursor position.
+    Preedit(String, Option<(usize, usize)>),
+
+    /// text should be inserted into the editor widget.
+    Commit(String),
+
+    /// the IME was disabled.
+    Disabled,
+}

core/src/lib.rs

@@ -17,6 +17,7 @@ pub mod event;
 pub mod font;
 pub mod gradient;
 pub mod image;
+pub mod input_method;
 pub mod keyboard;
 pub mod layout;
 pub mod mouse;
@@ -72,6 +73,7 @@ pub use renderer::Renderer;
 pub use rotation::Rotation;
 pub use settings::Settings;
 pub use shadow::Shadow;
+pub use shell::CaretInfo;
 pub use shell::Shell;
 pub use size::Size;
 pub use svg::Svg;

core/src/shell.rs

@@ -1,6 +1,15 @@
-use crate::event;
 use crate::time::Instant;
 use crate::window;
+use crate::{event, Point};
+
+/// TODO
+#[derive(Clone, Copy, Debug)]
+pub struct CaretInfo {
+    /// TODO
+    pub position: Point,
+    /// TODO
+    pub input_method_allowed: bool,
+}
 
 /// A connection to the state of a shell.
 ///
@@ -15,6 +24,7 @@ pub struct Shell<'a, Message> {
     redraw_request: Option<window::RedrawRequest>,
     is_layout_invalid: bool,
     are_widgets_invalid: bool,
+    caret_info: Option<CaretInfo>,
 }
 
 impl<'a, Message> Shell<'a, Message> {
@@ -26,6 +36,7 @@ impl<'a, Message> Shell<'a, Message> {
             redraw_request: None,
             is_layout_invalid: false,
             are_widgets_invalid: false,
+            caret_info: None,
         }
     }
 
@@ -80,6 +91,16 @@ impl<'a, Message> Shell<'a, Message> {
         self.redraw_request
     }
 
+    /// TODO
+    pub fn update_caret_info(&mut self, caret_info: Option<CaretInfo>) {
+        self.caret_info = caret_info.or(self.caret_info);
+    }
+
+    /// TODO
+    pub fn caret_info(&self) -> Option<CaretInfo> {
+        self.caret_info
+    }
+
     /// Returns whether the current layout is invalid or not.
     pub fn is_layout_invalid(&self) -> bool {
         self.is_layout_invalid
@@ -130,6 +151,8 @@ impl<'a, Message> Shell<'a, Message> {
             );
         }
 
+        self.update_caret_info(other.caret_info());
+
         self.is_layout_invalid =
             self.is_layout_invalid || other.is_layout_invalid;
 

runtime/src/user_interface.rs

@@ -5,7 +5,9 @@ use crate::core::mouse;
 use crate::core::renderer;
 use crate::core::widget;
 use crate::core::window;
-use crate::core::{Clipboard, Element, Layout, Rectangle, Shell, Size, Vector};
+use crate::core::{
+    CaretInfo, Clipboard, Element, Layout, Rectangle, Shell, Size, Vector,
+};
 use crate::overlay;
 
 /// A set of interactive graphical elements with a specific [`Layout`].
@@ -187,6 +189,7 @@ where
 
         let mut outdated = false;
         let mut redraw_request = None;
+        let mut caret_info = None;
 
         let mut manual_overlay = ManuallyDrop::new(
             self.root
@@ -230,6 +233,7 @@ where
                     }
                     _ => {}
                 }
+                caret_info = caret_info.or(shell.caret_info());
 
                 if shell.is_layout_invalid() {
                     let _ = ManuallyDrop::into_inner(manual_overlay);
@@ -332,6 +336,7 @@ where
                     }
                     _ => {}
                 }
+                caret_info = caret_info.or(shell.caret_info());
 
                 shell.revalidate_layout(|| {
                     self.base = self.root.as_widget().layout(
@@ -355,7 +360,10 @@ where
             if outdated {
                 State::Outdated
             } else {
-                State::Updated { redraw_request }
+                State::Updated {
+                    redraw_request,
+                    caret_info,
+                }
             },
             event_statuses,
         )
@@ -646,5 +654,7 @@ pub enum State {
     Updated {
         /// The [`window::RedrawRequest`] when a redraw should be performed.
         redraw_request: Option<window::RedrawRequest>,
+        /// TODO
+        caret_info: Option<CaretInfo>,
     },
 }

widget/src/combo_box.rs

@@ -564,6 +564,7 @@ where
                 }
             }
         }
+        shell.update_caret_info(local_shell.caret_info());
 
         // Then finally react to them here
         for message in local_messages {
@@ -742,6 +743,8 @@ where
                 published_message_to_shell = true;
 
                 // Unfocus the input
+                let mut local_messages = Vec::new();
+                let mut local_shell = Shell::new(&mut local_messages);
                 self.text_input.update(
                     &mut tree.children[0],
                     Event::Mouse(mouse::Event::ButtonPressed(
@@ -751,9 +754,10 @@ where
                     mouse::Cursor::Unavailable,
                     renderer,
                     clipboard,
-                    &mut Shell::new(&mut vec![]),
+                    &mut local_shell,
                     viewport,
                 );
+                shell.update_caret_info(local_shell.caret_info());
             }
         });
 

widget/src/lazy/component.rs

@@ -355,6 +355,7 @@ where
                 }
             }
         }
+        shell.update_caret_info(local_shell.caret_info());
 
         if !local_messages.is_empty() {
             let mut heads = self.state.take().unwrap().into_heads();
@@ -640,6 +641,7 @@ where
                 }
             }
         }
+        shell.update_caret_info(local_shell.caret_info());
 
         if !local_messages.is_empty() {
             let mut inner =

widget/src/scrollable.rs

@@ -33,8 +33,9 @@ use crate::core::widget::operation::{self, Operation};
 use crate::core::widget::tree::{self, Tree};
 use crate::core::window;
 use crate::core::{
-    self, Background, Clipboard, Color, Element, Event, Layout, Length,
-    Padding, Pixels, Point, Rectangle, Shell, Size, Theme, Vector, Widget,
+    self, Background, CaretInfo, Clipboard, Color, Element, Event, Layout,
+    Length, Padding, Pixels, Point, Rectangle, Shell, Size, Theme, Vector,
+    Widget,
 };
 use crate::runtime::task::{self, Task};
 use crate::runtime::Action;
@@ -729,6 +730,7 @@ where
                 let translation =
                     state.translation(self.direction, bounds, content_bounds);
 
+                let children_may_have_caret = shell.caret_info().is_none();
                 self.content.as_widget_mut().update(
                     &mut tree.children[0],
                     event.clone(),
@@ -743,6 +745,18 @@ where
                         ..bounds
                     },
                 );
+
+                if children_may_have_caret {
+                    if let Some(caret_info) = shell.caret_info() {
+                        shell.update_caret_info(Some(CaretInfo {
+                            position: Point::new(
+                                caret_info.position.x - translation.x,
+                                caret_info.position.y - translation.y,
+                            ),
+                            input_method_allowed: caret_info.input_method_allowed,
+                        }));
+                    }
+                }
             };
 
             if matches!(

widget/src/text_editor.rs

@@ -33,6 +33,7 @@
 //! ```
 use crate::core::alignment;
 use crate::core::clipboard::{self, Clipboard};
+use crate::core::input_method;
 use crate::core::keyboard;
 use crate::core::keyboard::key;
 use crate::core::layout::{self, Layout};
@@ -46,8 +47,8 @@ use crate::core::widget::operation;
 use crate::core::widget::{self, Widget};
 use crate::core::window;
 use crate::core::{
-    Background, Border, Color, Element, Event, Length, Padding, Pixels, Point,
-    Rectangle, Shell, Size, SmolStr, Theme, Vector,
+    Background, Border, CaretInfo, Color, Element, Event, Length, Padding,
+    Pixels, Point, Rectangle, Shell, Size, SmolStr, Theme, Vector,
 };
 
 use std::borrow::Cow;
@@ -322,6 +323,46 @@ where
         self.class = class.into();
         self
     }
+
+    fn caret_rect(
+        &self,
+        tree: &widget::Tree,
+        renderer: &Renderer,
+        layout: Layout<'_>,
+    ) -> Option<Rectangle> {
+        let bounds = layout.bounds();
+
+        let internal = self.content.0.borrow_mut();
+        let state = tree.state.downcast_ref::<State<Highlighter>>();
+
+        let text_bounds = bounds.shrink(self.padding);
+        let translation = text_bounds.position() - Point::ORIGIN;
+
+        if let Some(_) = state.focus.as_ref() {
+            let position = match internal.editor.cursor() {
+                Cursor::Caret(position) => position,
+                Cursor::Selection(ranges) => ranges
+                    .first()
+                    .cloned()
+                    .unwrap_or(Rectangle::default())
+                    .position(),
+            };
+            Some(Rectangle::new(
+                position + translation,
+                Size::new(
+                    1.0,
+                    self.line_height
+                        .to_absolute(
+                            self.text_size
+                                .unwrap_or_else(|| renderer.default_size()),
+                        )
+                        .into(),
+                ),
+            ))
+        } else {
+            None
+        }
+    }
 }
 
 /// The content of a [`TextEditor`].
@@ -605,7 +646,7 @@ where
         event: Event,
         layout: Layout<'_>,
         cursor: mouse::Cursor,
-        _renderer: &Renderer,
+        renderer: &Renderer,
         clipboard: &mut dyn Clipboard,
         shell: &mut Shell<'_, Message>,
         _viewport: &Rectangle,
@@ -701,6 +742,11 @@ where
                     }));
                     shell.capture_event();
                 }
+                Update::Commit(text) => {
+                    shell.publish(on_edit(Action::Edit(Edit::Paste(
+                        Arc::new(text),
+                    ))));
+                }
                 Update::Binding(binding) => {
                     fn apply_binding<
                         H: text::Highlighter,
@@ -825,6 +871,19 @@ where
             }
         };
 
+        shell.update_caret_info(if state.is_focused() {
+            let rect = self
+                .caret_rect(tree, renderer, layout)
+                .unwrap_or(Rectangle::default());
+            let bottom_left = Point::new(rect.x, rect.y + rect.height);
+            Some(CaretInfo {
+                position: bottom_left,
+                input_method_allowed: true,
+            })
+        } else {
+            None
+        });
+
         if is_redraw {
             self.last_status = Some(status);
         } else if self
@@ -1129,6 +1188,7 @@ enum Update<Message> {
     Drag(Point),
     Release,
     Scroll(f32),
+    Commit(String),
     Binding(Binding<Message>),
 }
 
@@ -1191,6 +1251,9 @@ impl<Message> Update<Message> {
                 }
                 _ => None,
             },
+            Event::InputMethod(input_method::Event::Commit(text)) => {
+                Some(Update::Commit(text))
+            }
             Event::Keyboard(keyboard::Event::KeyPressed {
                 key,
                 modifiers,