TextBuffer with DerefMut.

Author: nsabovic

Cargo.lock

@@ -1305,6 +1305,7 @@ dependencies = [
  "ahash",
  "backtrace",
  "bitflags 2.9.4",
+ "bytemuck",
  "document-features",
  "emath",
  "epaint",

crates/egui/Cargo.toml

@@ -74,6 +74,7 @@ epaint = { workspace = true, default-features = false }
 accesskit.workspace = true
 ahash.workspace = true
 bitflags.workspace = true
+bytemuck.workspace = true
 log.workspace = true
 nohash-hasher.workspace = true
 profiling.workspace = true

crates/egui/src/widgets/text_edit/builder.rs

@@ -1,5 +1,6 @@
-use std::sync::Arc;
+use std::{ops::DerefMut, sync::Arc};
 
+use bytemuck::TransparentWrapper as _;
 use emath::{Rect, TSTransform};
 use epaint::{
     StrokeKind,
@@ -12,8 +13,11 @@ use crate::{
     TextStyle, TextWrapMode, Ui, Vec2, Widget, WidgetInfo, WidgetText, WidgetWithState, epaint,
     os::OperatingSystem,
     output::OutputEvent,
-    response, text_selection,
-    text_selection::{CCursorRange, text_cursor_state::cursor_rect, visuals::paint_text_selection},
+    response,
+    text_edit::text_buffer::TextBufferRef,
+    text_selection::{
+        self, CCursorRange, text_cursor_state::cursor_rect, visuals::paint_text_selection,
+    },
     vec2,
 };
 
@@ -116,6 +120,14 @@ impl<'t> TextEdit<'t> {
         }
     }
 
+    pub fn singleline_ref<T>(smart_ptr: &'t mut T) -> Self
+    where
+        T: DerefMut,
+        T::Target: TextBuffer,
+    {
+        Self::singleline(TextBufferRef::wrap_mut(smart_ptr))
+    }
+
     /// A [`TextEdit`] for multiple lines. Pressing enter key will create a new line by default (can be changed with [`return_key`](TextEdit::return_key)).
     pub fn multiline(text: &'t mut dyn TextBuffer) -> Self {
         Self {
@@ -151,6 +163,14 @@ impl<'t> TextEdit<'t> {
         }
     }
 
+    pub fn multilne_ref<T>(smart_ptr: &'t mut T) -> Self
+    where
+        T: DerefMut,
+        T::Target: TextBuffer,
+    {
+        Self::multiline(TextBufferRef::wrap_mut(smart_ptr))
+    }
+
     /// Build a [`TextEdit`] focused on code editing.
     /// By default it comes with:
     /// - monospaced font

crates/egui/src/widgets/text_edit/text_buffer.rs

@@ -1,4 +1,7 @@
-use std::{borrow::Cow, ops::Range};
+use std::{
+    borrow::Cow,
+    ops::{Deref, DerefMut, Range},
+};
 
 use epaint::{
     Galley,
@@ -315,3 +318,45 @@ impl TextBuffer for &str {
         std::any::TypeId::of::<&str>()
     }
 }
+
+#[repr(transparent)]
+#[derive(bytemuck::TransparentWrapper)]
+pub struct TextBufferRef<T: ?Sized>(pub T);
+
+impl<T> TextBuffer for TextBufferRef<T>
+where
+    T: DerefMut + ?Sized,
+    <T as Deref>::Target: TextBuffer,
+{
+    fn is_mutable(&self) -> bool {
+        self.0.is_mutable()
+    }
+
+    fn as_str(&self) -> &str {
+        self.0.as_str()
+    }
+
+    fn insert_text(&mut self, text: &str, char_index: usize) -> usize {
+        self.0.insert_text(text, char_index)
+    }
+
+    fn delete_char_range(&mut self, char_range: Range<usize>) {
+        self.0.delete_char_range(char_range);
+    }
+
+    fn clear(&mut self) {
+        self.0.clear();
+    }
+
+    fn replace_with(&mut self, text: &str) {
+        self.0.replace_with(text);
+    }
+
+    fn take(&mut self) -> String {
+        self.0.take()
+    }
+
+    fn type_id(&self) -> std::any::TypeId {
+        std::any::TypeId::of::<()>()
+    }
+}