Implement textual hit testing

graphics/src/backend.rs

@@ -1,7 +1,7 @@
 //! Write a graphics backend.
 use iced_native::image;
 use iced_native::svg;
-use iced_native::{Font, Size};
+use iced_native::{Font, HitTestResult, Point, Size};
 
 /// The graphics backend of a [`Renderer`].
 ///
@@ -43,6 +43,23 @@ pub trait Text {
         font: Font,
         bounds: Size,
     ) -> (f32, f32);
+
+    /// Tests whether the provided point is within the boundaries of [`Text`]
+    /// laid out with the given parameters, returning information about
+    /// the nearest character.
+    ///
+    /// If nearest_only is true, the hit test does not consider whether the
+    /// the point is interior to any glyph bounds, returning only the character
+    /// with the nearest centeroid.
+    fn hit_test(
+        &self,
+        contents: &str,
+        size: f32,
+        font: Font,
+        bounds: Size,
+        point: Point,
+        nearest_only: bool,
+    ) -> HitTestResult;
 }
 
 /// A graphics backend that supports image rendering.

graphics/src/lib.rs

@@ -40,6 +40,6 @@ pub use transformation::Transformation;
 pub use viewport::Viewport;
 
 pub use iced_native::{
-    Background, Color, Font, HorizontalAlignment, Point, Rectangle, Size,
-    Vector, VerticalAlignment,
+    Background, Color, Font, HitTestResult, HorizontalAlignment, Point,
+    Rectangle, Size, Vector, VerticalAlignment,
 };

graphics/src/widget/text.rs

@@ -4,7 +4,8 @@ use crate::{Primitive, Renderer};
 use iced_native::mouse;
 use iced_native::text;
 use iced_native::{
-    Color, Font, HorizontalAlignment, Rectangle, Size, VerticalAlignment,
+    Color, Font, HitTestResult, HorizontalAlignment, Point, Rectangle, Size,
+    VerticalAlignment,
 };
 
 /// A paragraph of text.
@@ -35,6 +36,25 @@ where
             .measure(content, f32::from(size), font, bounds)
     }
 
+    fn hit_test(
+        &self,
+        content: &str,
+        size: f32,
+        font: Font,
+        bounds: Size,
+        point: Point,
+        nearest_only: bool,
+    ) -> HitTestResult {
+        self.backend().hit_test(
+            content,
+            size,
+            font,
+            bounds,
+            point,
+            nearest_only,
+        )
+    }
+
     fn draw(
         &mut self,
         defaults: &Self::Defaults,