Allow accessing clear color

Author: bugadani

backend-embedded-graphics/src/widgets/canvas.rs

@@ -23,9 +23,10 @@ use crate::{themes::Theme, EgCanvas, ToRectangle};
 
 pub trait CanvasProperties {
     type Color;
-    type Canvas: DrawTargetExt + Drawable<Color = Self::Color>;
+    type Canvas: DrawTarget<Color = Self::Color> + DrawTargetExt + Drawable<Color = Self::Color>;
 
     fn canvas(&mut self) -> &mut Self::Canvas;
+    fn clear_color(&mut self) -> Self::Color;
     fn measure(&self) -> MeasuredSize;
 }
 
@@ -48,6 +49,10 @@ where
         &mut self.canvas
     }
 
+    fn clear_color(&mut self) -> Self::Color {
+        self.clear_color
+    }
+
     fn measure(&self) -> MeasuredSize {
         MeasuredSize {
             width: W as u32,
@@ -105,6 +110,10 @@ where
         &mut self.canvas
     }
 
+    fn clear_color(&mut self) -> Self::Color {
+        self.clear_color
+    }
+
     fn measure(&self) -> MeasuredSize {
         MeasuredSize {
             width: self.canvas.bounding_box().size.width,

examples/canvas.rs

@@ -2,7 +2,7 @@ use std::{thread, time::Duration};
 
 use backend_embedded_graphics::{
     themes::{default::DefaultTheme, Theme},
-    widgets::canvas::{Canvas, CanvasStyle},
+    widgets::canvas::{Canvas, CanvasProperties, CanvasStyle},
     EgCanvas,
 };
 use embedded_graphics::{
@@ -203,7 +203,7 @@ fn main() {
                     })
                     .bind(&state)
                     .on_data_changed(|widget, state| {
-                        let clear_color = widget.canvas_properties.clear_color;
+                        let clear_color = widget.canvas_properties.clear_color();
                         let mut canvas = widget.canvas();
 
                         canvas.clear(clear_color).unwrap();