Apply magic value suggestion

---------

Co-authored-by: Daniel McNab <[email protected]>

masonry/src/render_root.rs

@@ -39,6 +39,10 @@ use crate::text::BrushIndex;
 use crate::widget::{WidgetArena, WidgetMut, WidgetRef, WidgetState};
 use crate::{AccessEvent, Action, CursorIcon, Handled, QueryCtx, Widget, WidgetId, WidgetPod};
 
+/// We ensure that any valid initial IME area is sent to the platform by storing an invalid initial
+/// IME area as the last sent ime area.
+const INVALID_IME_AREA: Rect = Rect::new(f64::NAN, f64::NAN, f64::NAN, f64::NAN);
+
 // --- MARK: STRUCTS ---
 
 pub struct RenderRoot {
@@ -74,6 +78,9 @@ pub(crate) struct RenderRootState {
     pub(crate) text_layout_context: LayoutContext<BrushIndex>,
     pub(crate) mutate_callbacks: Vec<MutateCallback>,
     pub(crate) is_ime_active: bool,
+    /// The IME area last sent to the platform.
+    ///
+    /// This allows only sending the area to the platform when the area has changed.
     pub(crate) last_sent_ime_area: Rect,
     pub(crate) scenes: HashMap<WidgetId, Scene>,
     /// Whether data set in the pointer pass has been invalidated.
@@ -171,7 +178,7 @@ impl RenderRoot {
                 text_layout_context: LayoutContext::new(),
                 mutate_callbacks: Vec::new(),
                 is_ime_active: false,
-                last_sent_ime_area: Rect::new(f64::NAN, f64::NAN, f64::NAN, f64::NAN),
+                last_sent_ime_area: INVALID_IME_AREA,
                 scenes: HashMap::new(),
                 needs_pointer_pass: false,
                 trace: PassTracing::from_env(),
@@ -269,8 +276,7 @@ impl RenderRoot {
         if matches!(event, TextEvent::Ime(winit::event::Ime::Enabled)) {
             // Reset the last sent IME area, as the platform reset the IME state and may have
             // forgotten it.
-            self.global_state.last_sent_ime_area =
-                Rect::new(f64::NAN, f64::NAN, f64::NAN, f64::NAN);
+            self.global_state.last_sent_ime_area = INVALID_IME_AREA;
         }
         self.run_rewrite_passes();