Draft input_method support

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,