feat: Add rtl support to text input

core/src/text.rs

@@ -278,16 +278,34 @@ impl Hash for LineHeight {
 #[derive(Debug, Clone, Copy, PartialEq)]
 pub enum Hit {
     /// The point was within the bounds of the returned character index.
-    CharOffset(usize),
+    CharOffset(usize, Affinity),
 }
 
 impl Hit {
     /// Computes the cursor position of the [`Hit`] .
     pub fn cursor(self) -> usize {
         match self {
-            Self::CharOffset(i) => i,
+            Self::CharOffset(i, _) => i,
         }
     }
+
+    /// Returns the cursor [`Affinity`] of the [`Hit`].
+    pub fn affinity(&self) -> Affinity {
+        match self {
+            Self::CharOffset(_, a) => *a,
+        }
+    }
+}
+
+/// Cursor affinity for BiDi text. At the boundary between runs of different
+/// directions, the same byte index can map to different visual positions.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
+pub enum Affinity {
+    /// Associate with the run before the cursor index.
+    #[default]
+    Before,
+    /// Associate with the run after the cursor index.
+    After,
 }
 
 /// The difference detected in some text.

core/src/text/paragraph.rs

@@ -1,7 +1,8 @@
 //! Draw paragraphs.
 use crate::alignment;
 use crate::text::{
-    Alignment, Difference, Hit, LineHeight, Shaping, Span, Text, Wrapping,
+    Affinity, Alignment, Difference, Hit, LineHeight, Shaping, Span, Text,
+    Wrapping,
 };
 use crate::{Pixels, Point, Rectangle, Size};
 
@@ -71,6 +72,32 @@ pub trait Paragraph: Sized + Default {
     /// Returns the distance to the given grapheme index in the [`Paragraph`].
     fn grapheme_position(&self, line: usize, index: usize) -> Option<Point>;
 
+    /// Returns the visual position of a cursor at the given byte index and [`Affinity`].
+    fn cursor_position(
+        &self,
+        _line: usize,
+        _byte_index: usize,
+        _affinity: Affinity,
+    ) -> Option<Point> {
+        None
+    }
+
+    /// Returns highlight rectangles for a text selection. For mixed BiDi text,
+    /// this may return multiple rectangles.
+    fn highlight(
+        &self,
+        _line: usize,
+        _start: (usize, Affinity),
+        _end: (usize, Affinity),
+    ) -> Vec<Rectangle> {
+        Vec::new()
+    }
+
+    /// Returns `true` if the line is RTL, `false` for LTR.
+    fn is_rtl(&self, _line: usize) -> Option<bool> {
+        None
+    }
+
     /// Returns the minimum width that can fit the contents of the [`Paragraph`].
     fn min_width(&self) -> f32 {
         self.min_bounds().width
@@ -81,7 +108,6 @@ pub trait Paragraph: Sized + Default {
         self.min_bounds().height
     }
 
-
     /// Returns the [`Ellipsize`] strategy of the [`Paragraph`]>
     fn ellipsize(&self) -> Ellipsize;
 }
@@ -180,7 +206,7 @@ impl<P: Paragraph> Plain<P> {
             align_y: self.raw.align_y(),
             shaping: self.raw.shaping(),
             wrapping: self.raw.wrapping(),
-            ellipsize: self.raw.ellipsize()
+            ellipsize: self.raw.ellipsize(),
         }
     }
 }