feat: support for custom & system themes + move cosmic-theme to libcosmic

examples/cosmic/src/window.rs

@@ -1,6 +1,7 @@
 /// Copyright 2022 System76 <info@system76.com>
 // SPDX-License-Identifier: MPL-2.0
 use cosmic::{
+    cosmic_config::config_subscription,
     font::load_fonts,
     iced::{self, Application, Command, Length, Subscription},
     iced::{
@@ -9,15 +10,20 @@ use cosmic::{
         window::{self, close, drag, minimize, toggle_maximize},
     },
     keyboard_nav,
-    theme::{self, Theme},
+    theme::{self, CosmicTheme, CosmicThemeCss, Theme},
     widget::{
         header_bar, icon, list, nav_bar, nav_bar_toggle, scrollable, segmented_button, settings,
         warning, IconSource,
     },
     Element, ElementExt,
 };
+use log::error;
 use std::{
-    sync::atomic::{AtomicU32, Ordering},
+    borrow::Cow,
+    sync::{
+        atomic::{AtomicU32, Ordering},
+        Arc,
+    },
     vec,
 };
 
@@ -154,6 +160,7 @@ pub struct Window {
     warning_message: String,
     scale_factor: f64,
     scale_factor_string: String,
+    system_theme: Arc<CosmicTheme>,
 }
 
 impl Window {
@@ -198,6 +205,7 @@ pub enum Message {
     ToggleNavBarCondensed,
     ToggleWarning,
     FontsLoaded,
+    SystemTheme(CosmicTheme),
 }
 
 impl From<Page> for Message {
@@ -375,6 +383,16 @@ impl Application for Window {
         Subscription::batch(vec![
             window_break.map(|_| Message::CondensedViewToggle),
             keyboard_nav::subscription().map(Message::KeyboardNav),
+            config_subscription::<_, CosmicThemeCss>(0, Cow::from("com.system76.CosmicTheme"), 1)
+                .map(|(_, update)| match update {
+                    Ok(t) => Message::SystemTheme(t.into_srgba()),
+                    Err((errors, t)) => {
+                        for error in errors {
+                            error!("{:?}", error);
+                        }
+                        Message::SystemTheme(t.into_srgba())
+                    }
+                }),
         ])
     }
 
@@ -395,7 +413,13 @@ impl Application for Window {
                 Some(demo::Output::Debug(debug)) => self.debug = debug,
                 Some(demo::Output::ScalingFactor(factor)) => self.set_scale_factor(factor),
                 Some(demo::Output::ThemeChanged(theme)) => {
-                    self.theme = theme;
+                    self.theme = match theme {
+                        demo::ThemeVariant::Light => Theme::light(),
+                        demo::ThemeVariant::Dark => Theme::dark(),
+                        demo::ThemeVariant::HighContrastDark => Theme::dark_hc(),
+                        demo::ThemeVariant::HighContrastLight => Theme::light_hc(),
+                        demo::ThemeVariant::Custom => Theme::custom(self.system_theme.clone()),
+                    };
                 }
                 Some(demo::Output::ToggleWarning) => self.toggle_warning(),
                 None => (),
@@ -425,6 +449,9 @@ impl Application for Window {
             },
             Message::ToggleWarning => self.toggle_warning(),
             Message::FontsLoaded => {}
+            Message::SystemTheme(t) => {
+                self.system_theme = Arc::new(t);
+            }
         }
         ret
     }
@@ -572,6 +599,6 @@ impl Application for Window {
     }
 
     fn theme(&self) -> Theme {
-        self.theme
+        self.theme.clone()
     }
 }