Implement theme styling for ProgressBar

style/src/progress_bar.rs

@@ -1,9 +1,9 @@
 //! Provide progress feedback to your users.
-use iced_core::{Background, Color};
+use iced_core::Background;
 
 /// The appearance of a progress bar.
 #[derive(Debug, Clone, Copy)]
-pub struct Style {
+pub struct Appearance {
     pub background: Background,
     pub bar: Background,
     pub border_radius: f32,
@@ -11,32 +11,7 @@ pub struct Style {
 
 /// A set of rules that dictate the style of a progress bar.
 pub trait StyleSheet {
-    fn style(&self) -> Style;
-}
+    type Style: Default + Copy;
 
-struct Default;
-
-impl StyleSheet for Default {
-    fn style(&self) -> Style {
-        Style {
-            background: Background::Color(Color::from_rgb(0.6, 0.6, 0.6)),
-            bar: Background::Color(Color::from_rgb(0.3, 0.9, 0.3)),
-            border_radius: 5.0,
-        }
-    }
-}
-
-impl<'a> std::default::Default for Box<dyn StyleSheet + 'a> {
-    fn default() -> Self {
-        Box::new(Default)
-    }
-}
-
-impl<'a, T> From<T> for Box<dyn StyleSheet + 'a>
-where
-    T: 'a + StyleSheet,
-{
-    fn from(style: T) -> Self {
-        Box::new(style)
-    }
+    fn appearance(&self, style: Self::Style) -> Appearance;
 }

style/src/theme.rs

@@ -5,6 +5,7 @@ pub use self::palette::Palette;
 use crate::application;
 use crate::button;
 use crate::pane_grid;
+use crate::progress_bar;
 use crate::radio;
 use crate::rule;
 use crate::slider;
@@ -281,6 +282,44 @@ impl pane_grid::StyleSheet for Theme {
     }
 }
 
+/*
+ * Progress Bar
+ */
+#[derive(Clone, Copy)]
+pub enum ProgressBar {
+    Primary,
+    Success,
+    Danger,
+    Custom(fn(&Theme) -> progress_bar::Appearance),
+}
+
+impl Default for ProgressBar {
+    fn default() -> Self {
+        Self::Primary
+    }
+}
+
+impl progress_bar::StyleSheet for Theme {
+    type Style = ProgressBar;
+
+    fn appearance(&self, style: Self::Style) -> progress_bar::Appearance {
+        let palette = self.extended_palette();
+
+        let from_palette = |bar: Color| progress_bar::Appearance {
+            background: palette.background.weak.color.into(),
+            bar: bar.into(),
+            border_radius: 2.0,
+        };
+
+        match style {
+            ProgressBar::Primary => from_palette(palette.primary.base.color),
+            ProgressBar::Success => from_palette(palette.success.base.color),
+            ProgressBar::Danger => from_palette(palette.danger.base.color),
+            ProgressBar::Custom(f) => f(self),
+        }
+    }
+}
+
 /*
  * Rule
  */