Merge pull request #150 from hecrj/refactor/move-renderer-traits

Move `Debugger` and `Windowed` traits

native/src/layout/debugger.rs

@@ -0,0 +1,26 @@
+use crate::{Color, Layout, Point, Renderer, Widget};
+
+/// A renderer able to graphically explain a [`Layout`].
+///
+/// [`Layout`]: struct.Layout.html
+pub trait Debugger: Renderer {
+    /// Explains the [`Layout`] of an [`Element`] for debugging purposes.
+    ///
+    /// This will be called when [`Element::explain`] has been used. It should
+    /// _explain_ the given [`Layout`] graphically.
+    ///
+    /// A common approach consists in recursively rendering the bounds of the
+    /// [`Layout`] and its children.
+    ///
+    /// [`Layout`]: struct.Layout.html
+    /// [`Element`]: ../struct.Element.html
+    /// [`Element::explain`]: ../struct.Element.html#method.explain
+    fn explain<Message>(
+        &mut self,
+        defaults: &Self::Defaults,
+        widget: &dyn Widget<Message, Self>,
+        layout: Layout<'_>,
+        cursor_position: Point,
+        color: Color,
+    ) -> Self::Output;
+}