Merge remote-tracking branch 'origin/master' into feat/multi-window-support

# Conflicts:
#	Cargo.toml
#	core/src/window/icon.rs
#	core/src/window/id.rs
#	core/src/window/position.rs
#	core/src/window/settings.rs
#	examples/integration/src/main.rs
#	examples/integration_opengl/src/main.rs
#	glutin/src/application.rs
#	native/src/subscription.rs
#	native/src/window.rs
#	runtime/src/window/action.rs
#	src/lib.rs
#	src/window.rs
#	winit/Cargo.toml
#	winit/src/application.rs
#	winit/src/icon.rs
#	winit/src/settings.rs
#	winit/src/window.rs

1 files changed, 76 insertions, 0 deletions

diff --git a/core/src/renderer.rs b/core/src/renderer.rs
new file mode 100644
index 00000000..7c73d2e4
--- /dev/null
+++ b/core/src/renderer.rs
@@ -0,0 +1,76 @@
+//! Write your own renderer.
+#[cfg(debug_assertions)]
+mod null;
+
+#[cfg(debug_assertions)]
+pub use null::Null;
+
+use crate::layout;
+use crate::{Background, BorderRadius, Color, Element, Rectangle, Vector};
+
+/// A component that can be used by widgets to draw themselves on a screen.
+pub trait Renderer: Sized {
+    /// The supported theme of the [`Renderer`].
+    type Theme;
+
+    /// Lays out the elements of a user interface.
+    ///
+    /// You should override this if you need to perform any operations before or
+    /// after layouting. For instance, trimming the measurements cache.
+    fn layout<Message>(
+        &mut self,
+        element: &Element<'_, Message, Self>,
+        limits: &layout::Limits,
+    ) -> layout::Node {
+        element.as_widget().layout(self, limits)
+    }
+
+    /// Draws the primitives recorded in the given closure in a new layer.
+    ///
+    /// The layer will clip its contents to the provided `bounds`.
+    fn with_layer(&mut self, bounds: Rectangle, f: impl FnOnce(&mut Self));
+
+    /// Applies a `translation` to the primitives recorded in the given closure.
+    fn with_translation(
+        &mut self,
+        translation: Vector,
+        f: impl FnOnce(&mut Self),
+    );
+
+    /// Fills a [`Quad`] with the provided [`Background`].
+    fn fill_quad(&mut self, quad: Quad, background: impl Into<Background>);
+
+    /// Clears all of the recorded primitives in the [`Renderer`].
+    fn clear(&mut self);
+}
+
+/// A polygon with four sides.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct Quad {
+    /// The bounds of the [`Quad`].
+    pub bounds: Rectangle,
+
+    /// The border radius of the [`Quad`].
+    pub border_radius: BorderRadius,
+
+    /// The border width of the [`Quad`].
+    pub border_width: f32,
+
+    /// The border color of the [`Quad`].
+    pub border_color: Color,
+}
+
+/// The styling attributes of a [`Renderer`].
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct Style {
+    /// The text color
+    pub text_color: Color,
+}
+
+impl Default for Style {
+    fn default() -> Self {
+        Style {
+            text_color: Color::BLACK,
+        }
+    }
+}