Signal TextFieldFocused and ImeMoved to enable and position the IME. (#314)

masonry/src/contexts.rs

@@ -679,6 +679,14 @@ impl PaintCtx<'_> {
     pub fn depth(&self) -> u32 {
         self.depth
     }
+
+    // signal may be useful elsewhere, but is currently only used on PaintCtx
+    /// Submit a [`RenderRootSignal`]
+    ///
+    /// Note: May be removed in future, and replaced with more specific methods.
+    pub fn signal(&mut self, s: RenderRootSignal) {
+        self.global_state.signal_queue.push_back(s);
+    }
 }
 
 impl AccessCtx<'_> {

masonry/src/event_loop_runner.rs

@@ -119,8 +119,6 @@ impl ApplicationHandler<accesskit_winit::Event> for MainState<'_> {
 
                 let adapter = Adapter::with_event_loop_proxy(&window, self.proxy.clone());
                 window.set_visible(visible);
-                // TODO: Use signals or some other mechanism to do fine grained ime enable
-                window.set_ime_allowed(true);
                 let window = Arc::new(window);
                 let size = window.inner_size();
                 let surface = pollster::block_on(self.render_cx.create_surface(
@@ -428,23 +426,14 @@ impl MainState<'_> {
                             .on_action(&mut driver_ctx, widget_id, action);
                     });
                 }
-                render_root::RenderRootSignal::TextFieldAdded => {
-                    // TODO
+                render_root::RenderRootSignal::StartIme => {
+                    window.set_ime_allowed(true);
                 }
-                render_root::RenderRootSignal::TextFieldRemoved => {
-                    // TODO
+                render_root::RenderRootSignal::EndIme => {
+                    window.set_ime_allowed(false);
                 }
-                render_root::RenderRootSignal::TextFieldFocused => {
-                    // TODO
-                }
-                render_root::RenderRootSignal::ImeStarted => {
-                    // TODO
-                }
-                render_root::RenderRootSignal::ImeMoved => {
-                    // TODO
-                }
-                render_root::RenderRootSignal::ImeInvalidated => {
-                    // TODO
+                render_root::RenderRootSignal::ImeMoved(position, size) => {
+                    window.set_ime_cursor_area(position, size);
                 }
                 render_root::RenderRootSignal::RequestRedraw => {
                     window.request_redraw();

masonry/src/render_root.rs

@@ -71,12 +71,9 @@ pub enum WindowSizePolicy {
 // TODO - Text fields
 pub enum RenderRootSignal {
     Action(Action, WidgetId),
-    TextFieldAdded,
-    TextFieldRemoved,
-    TextFieldFocused,
-    ImeStarted,
-    ImeMoved,
-    ImeInvalidated,
+    StartIme,
+    EndIme,
+    ImeMoved(LogicalPosition<f64>, LogicalSize<f64>),
     RequestRedraw,
     RequestAnimFrame,
     SpawnWorker(WorkerFn),
@@ -584,8 +581,12 @@ impl RenderRoot {
             self.state.focused_widget = new;
             self.root_lifecycle(event);
 
-            // TODO - Handle IME
-            // Send TextFieldFocused(focused_widget) signal
+            // TODO: discriminate between text focus, and non-text focus.
+            self.state.signal_queue.push_back(if new.is_some() {
+                RenderRootSignal::StartIme
+            } else {
+                RenderRootSignal::EndIme
+            });
         }
     }
 

masonry/src/widget/textbox.rs

@@ -13,6 +13,7 @@ use vello::{
     peniko::{BlendMode, Color},
     Scene,
 };
+use winit::dpi::{LogicalPosition, LogicalSize};
 
 use crate::{
     text2::{TextBrush, TextEditor, TextStorage, TextWithSelection},
@@ -301,7 +302,8 @@ impl Widget for Textbox {
         self.editor
             .draw(scene, Point::new(TEXTBOX_PADDING, TEXTBOX_PADDING));
 
-        let outline_rect = ctx.size().to_rect().inset(1.0);
+        let size = ctx.size();
+        let outline_rect = size.to_rect().inset(1.0);
         scene.stroke(
             &Stroke::new(1.0),
             Affine::IDENTITY,
@@ -312,6 +314,19 @@ impl Widget for Textbox {
         if self.line_break_mode == LineBreaking::Clip {
             scene.pop_layer();
         }
+        let origin = ctx.widget_state.window_origin();
+        if ctx.widget_state.has_focus {
+            ctx.signal(crate::render_root::RenderRootSignal::ImeMoved(
+                LogicalPosition {
+                    x: origin.x,
+                    y: origin.y + size.height,
+                },
+                LogicalSize {
+                    width: size.width,
+                    height: size.height,
+                },
+            ));
+        }
     }
 
     fn accessibility_role(&self) -> Role {