Introduce Border struct analogous to Shadow

examples/custom_quad/src/main.rs

@@ -3,8 +3,8 @@ mod quad {
     use iced::advanced::layout::{self, Layout};
     use iced::advanced::renderer;
     use iced::advanced::widget::{self, Widget};
-    use iced::{mouse, Shadow};
-    use iced::{Color, Element, Length, Rectangle, Size};
+    use iced::mouse;
+    use iced::{Border, Color, Element, Length, Rectangle, Shadow, Size};
 
     pub struct CustomQuad {
         size: f32,
@@ -62,10 +62,12 @@ mod quad {
             renderer.fill_quad(
                 renderer::Quad {
                     bounds: layout.bounds(),
-                    border_radius: self.radius.into(),
-                    border_width: self.border_width,
-                    border_color: Color::from_rgb(1.0, 0.0, 0.0),
-                    shadow: Some(self.shadow),
+                    border: Border {
+                        radius: self.radius.into(),
+                        width: self.border_width,
+                        color: Color::from_rgb(1.0, 0.0, 0.0),
+                    },
+                    shadow: self.shadow,
                 },
                 Color::BLACK,
             );

examples/custom_widget/src/main.rs

@@ -13,7 +13,7 @@ mod circle {
     use iced::advanced::renderer;
     use iced::advanced::widget::{self, Widget};
     use iced::mouse;
-    use iced::{Color, Element, Length, Rectangle, Size};
+    use iced::{Border, Color, Element, Length, Rectangle, Size};
 
     pub struct Circle {
         radius: f32,
@@ -62,7 +62,7 @@ mod circle {
             renderer.fill_quad(
                 renderer::Quad {
                     bounds: layout.bounds(),
-                    border_radius: self.radius.into(),
+                    border: Border::with_radius(self.radius),
                     ..renderer::Quad::default()
                 },
                 Color::BLACK,

examples/modal/src/main.rs

@@ -231,10 +231,7 @@ mod modal {
     use iced::alignment::Alignment;
     use iced::event;
     use iced::mouse;
-    use iced::{
-        BorderRadius, Color, Element, Event, Length, Point, Rectangle, Size,
-        Vector,
-    };
+    use iced::{Color, Element, Event, Length, Point, Rectangle, Size, Vector};
 
     /// A widget that centers a modal element over some base element
     pub struct Modal<'a, Message, Renderer> {
@@ -474,7 +471,6 @@ mod modal {
             renderer.fill_quad(
                 renderer::Quad {
                     bounds: layout.bounds(),
-                    border_radius: BorderRadius::default(),
                     ..renderer::Quad::default()
                 },
                 Color {

examples/pane_grid/src/main.rs

@@ -348,7 +348,7 @@ fn view_controls<'a>(
 
 mod style {
     use iced::widget::container;
-    use iced::Theme;
+    use iced::{Border, Theme};
 
     pub fn title_bar_active(theme: &Theme) -> container::Appearance {
         let palette = theme.extended_palette();
@@ -375,8 +375,11 @@ mod style {
 
         container::Appearance {
             background: Some(palette.background.weak.color.into()),
-            border_width: 2.0,
-            border_color: palette.background.strong.color,
+            border: Border {
+                width: 2.0,
+                color: palette.background.strong.color,
+                ..Border::default()
+            },
             ..Default::default()
         }
     }
@@ -386,8 +389,11 @@ mod style {
 
         container::Appearance {
             background: Some(palette.background.weak.color.into()),
-            border_width: 2.0,
-            border_color: palette.primary.strong.color,
+            border: Border {
+                width: 2.0,
+                color: palette.primary.strong.color,
+                ..Border::default()
+            },
             ..Default::default()
         }
     }

examples/scrollable/src/main.rs

@@ -1,10 +1,14 @@
+use iced::executor;
+use iced::theme;
 use iced::widget::scrollable::{Properties, Scrollbar, Scroller};
 use iced::widget::{
     button, column, container, horizontal_space, progress_bar, radio, row,
     scrollable, slider, text, vertical_space,
 };
-use iced::{executor, theme, Alignment, Color};
-use iced::{Application, Command, Element, Length, Settings, Theme};
+use iced::{
+    Alignment, Application, Border, Color, Command, Element, Length, Settings,
+    Theme,
+};
 
 use once_cell::sync::Lazy;
 
@@ -373,14 +377,10 @@ impl scrollable::StyleSheet for ScrollbarCustomStyle {
                 background: style
                     .active(&theme::Scrollable::default())
                     .background,
-                border_radius: 2.0.into(),
-                border_width: 0.0,
-                border_color: Color::default(),
+                border: Border::with_radius(2),
                 scroller: Scroller {
                     color: Color::from_rgb8(250, 85, 134),
-                    border_radius: 2.0.into(),
-                    border_width: 0.0,
-                    border_color: Color::default(),
+                    border: Border::with_radius(2),
                 },
             }
         } else {