chore: use with_alpha() where applicable

cosmic-theme/src/model/derivation.rs

@@ -1,4 +1,4 @@
-use palette::Srgba;
+use palette::{Srgba, WithAlpha};
 use serde::{Deserialize, Serialize};
 
 use crate::composite::over;
@@ -27,9 +27,7 @@ impl Container {
         mut small_widget: Srgba,
         is_high_contrast: bool,
     ) -> Self {
-        let mut divider_c = on;
-        divider_c.alpha = if is_high_contrast { 0.5 } else { 0.2 };
-
+        let divider_c = on.with_alpha(if is_high_contrast { 0.5 } else { 0.2 });
         small_widget.alpha = 0.25;
 
         Self {
@@ -115,13 +113,11 @@ impl Component {
         hovered: Srgba,
         pressed: Srgba,
     ) -> Self {
-        let base: Srgba = base;
         let mut base_50 = base;
         base_50.alpha *= 0.5;
 
         let on_20 = neutral;
-        let mut on_50: Srgba = on_20;
-        on_50.alpha = 0.5;
+        let on_50 = on_20.with_alpha(0.5);
 
         Component {
             base,
@@ -151,8 +147,7 @@ impl Component {
         let mut component = Component::colored_component(base, overlay, accent, hovered, pressed);
         component.on = on_button;
 
-        let mut on_disabled = on_button;
-        on_disabled.alpha = 0.5;
+        let on_disabled = on_button.with_alpha(0.5);
         component.on_disabled = on_disabled;
 
         component
@@ -172,11 +167,8 @@ impl Component {
         let mut base_50 = base;
         base_50.alpha *= 0.5;
 
-        let mut on_20 = on_component;
-        let mut on_50 = on_20;
-
-        on_20.alpha = 0.2;
-        on_50.alpha = 0.5;
+        let on_20 = on_component.with_alpha(0.2);
+        let on_50 = on_20.with_alpha(0.5);
 
         let mut disabled_border = border;
         disabled_border.alpha *= 0.5;

cosmic-theme/src/model/theme.rs

@@ -1,11 +1,13 @@
 use crate::{
     composite::over,
-    steps::{color_index, get_index, get_small_widget_color, get_surface_color, get_text, steps},
+    steps::{color_index, get_small_widget_color, get_surface_color, get_text, steps},
     Component, Container, CornerRadii, CosmicPalette, CosmicPaletteInner, Spacing, ThemeMode,
     DARK_PALETTE, LIGHT_PALETTE, NAME,
 };
 use cosmic_config::{Config, CosmicConfigEntry};
-use palette::{color_difference::Wcag21RelativeContrast, rgb::Rgb, IntoColor, Oklcha, Srgb, Srgba};
+use palette::{
+    color_difference::Wcag21RelativeContrast, rgb::Rgb, IntoColor, Oklcha, Srgb, Srgba, WithAlpha,
+};
 use serde::{Deserialize, Serialize};
 use std::num::NonZeroUsize;
 
@@ -309,9 +311,7 @@ impl Theme {
     #[inline]
     /// get @small_widget_divider
     pub fn small_widget_divider(&self) -> Srgba {
-        let mut neutral_9 = self.palette.neutral_9;
-        neutral_9.alpha = 0.2;
-        neutral_9
+        self.palette.neutral_9.with_alpha(0.2)
     }
 
     // Containers
@@ -1041,16 +1041,12 @@ impl ThemeBuilder {
         component_pressed_overlay.alpha = 0.2;
 
         // Standard button background is neutral 7 with 25% opacity
-        let button_bg = {
-            let mut color = control_steps_array[7];
-            color.alpha = 0.25;
-            color
-        };
+        let button_bg = control_steps_array[7].with_alpha(0.25);
 
-        let (mut button_hovered_overlay, mut button_pressed_overlay) =
-            (control_steps_array[5], control_steps_array[2]);
-        button_hovered_overlay.alpha = 0.2;
-        button_pressed_overlay.alpha = 0.5;
+        let (button_hovered_overlay, button_pressed_overlay) = (
+            control_steps_array[5].with_alpha(0.2),
+            control_steps_array[2].with_alpha(0.5),
+        );
 
         let bg_component = get_surface_color(bg_index, 8, &step_array, is_dark, &p_ref.neutral_2);
         let on_bg_component = get_text(
@@ -1288,10 +1284,7 @@ impl ThemeBuilder {
                     control_steps_array[8],
                 );
 
-                let mut on_50 = component.on;
-                on_50.alpha = 0.5;
-
-                component.on_disabled = over(on_50, component.base);
+                component.on_disabled = over(component.on.with_alpha(0.5), component.base);
                 component
             },
             success: Component::colored_component(

cosmic-theme/src/output/gtk4_output.rs

@@ -1,5 +1,5 @@
 use crate::{composite::over, steps::steps, Component, Theme};
-use palette::{rgb::Rgba, Darken, IntoColor, Lighten, Srgba};
+use palette::{rgb::Rgba, Darken, IntoColor, Lighten, Srgba, WithAlpha};
 use std::{
     fs::{self, File},
     io::{self, Write},
@@ -75,8 +75,7 @@ impl Theme {
             Rgba::new(0.0, 0.0, 0.0, 0.08)
         });
 
-        let mut inverted_bg_divider = background.base;
-        inverted_bg_divider.alpha = 0.5;
+        let inverted_bg_divider = background.base.with_alpha(0.5);
         let scrollbar_outline = to_rgba(inverted_bg_divider);
 
         let mut css = format! {r#"/* GENERATED BY COSMIC */