Add Shadow to container::Appearance

style/src/container.rs

@@ -1,5 +1,5 @@
 //! Change the appearance of a container.
-use crate::core::{Background, Border, Color, Pixels};
+use crate::core::{Background, Border, Color, Pixels, Shadow};
 
 /// The appearance of a container.
 #[derive(Debug, Clone, Copy, Default)]
@@ -10,6 +10,8 @@ pub struct Appearance {
     pub background: Option<Background>,
     /// The [`Border`] of the container.
     pub border: Border,
+    /// The [`Shadow`] of the container.
+    pub shadow: Shadow,
 }
 
 impl Appearance {

style/src/theme.rs

@@ -21,7 +21,7 @@ use crate::text_editor;
 use crate::text_input;
 use crate::toggler;
 
-use crate::core::{Background, Border, Color, Vector};
+use crate::core::{Background, Border, Color, Shadow, Vector};
 
 use std::fmt;
 use std::rc::Rc;
@@ -434,6 +434,7 @@ impl container::StyleSheet for Theme {
                     text_color: None,
                     background: Some(palette.background.weak.color.into()),
                     border: Border::with_radius(2),
+                    shadow: Shadow::default(),
                 }
             }
             Container::Custom(custom) => custom.appearance(self),

widget/src/button.rs

@@ -392,15 +392,14 @@ where
     };
 
     if styling.background.is_some()
-        || styling.shadow.color.a > 0.0
         || styling.border.width > 0.0
+        || styling.shadow.color.a > 0.0
     {
         renderer.fill_quad(
             renderer::Quad {
                 bounds,
                 border: styling.border,
                 shadow: styling.shadow,
-                ..renderer::Quad::default()
             },
             styling
                 .background

widget/src/container.rs

@@ -337,12 +337,15 @@ pub fn draw_background<Renderer>(
 ) where
     Renderer: crate::core::Renderer,
 {
-    if appearance.background.is_some() || appearance.border.width > 0.0 {
+    if appearance.background.is_some()
+        || appearance.border.width > 0.0
+        || appearance.shadow.color.a > 0.0
+    {
         renderer.fill_quad(
             renderer::Quad {
                 bounds,
                 border: appearance.border,
-                ..renderer::Quad::default()
+                shadow: appearance.shadow,
             },
             appearance
                 .background