feat(wallpaper): update slideshow preview in realtime

app/src/app.rs

@@ -12,7 +12,7 @@ use crate::pages::desktop::{
     },
 };
 use crate::pages::input::{self, keyboard};
-use crate::pages::{display, sound, system, time};
+use crate::pages::{self, display, sound, system, time};
 use crate::subscription::desktop_files;
 use crate::widget::{page_title, search_header};
 use crate::PageCommands;
@@ -21,7 +21,7 @@ use cosmic::iced::Subscription;
 use cosmic::widget::{button, row, text_input};
 use cosmic::{
     app::{Command, Core},
-    cosmic_config::config_subscription,
+    cosmic_config::{config_state_subscription, config_subscription},
     iced::{
         self,
         event::{self, wayland, PlatformSpecific},
@@ -228,6 +228,11 @@ impl cosmic::Application for SettingsApp {
 
                 Message::PanelConfig(update.config)
             }),
+            config_state_subscription(0, cosmic_bg_config::NAME.into(), 1).map(|update| {
+                Message::PageMessage(pages::Message::DesktopWallpaper(
+                    pages::desktop::wallpaper::Message::UpdateState(update.config),
+                ))
+            }),
         ])
     }
 

app/src/pages/desktop/wallpaper/mod.rs

@@ -115,6 +115,8 @@ pub enum Message {
     Select(DefaultKey),
     /// Changes the slideshow parameter.
     Slideshow(bool),
+    /// State change from cosmic-bg
+    UpdateState(cosmic_bg_config::state::State),
 }
 
 impl From<Message> for crate::app::Message {
@@ -615,6 +617,12 @@ impl Page {
     #[allow(clippy::too_many_lines)]
     pub fn update(&mut self, message: Message) -> Command<crate::app::Message> {
         match message {
+            Message::UpdateState(_state) => {
+                if let Choice::Slideshow = self.selection.active {
+                    self.cache_display_image();
+                }
+            }
+
             Message::DragColorDialog => {
                 return cosmic::iced_sctk::commands::window::start_drag_window(self.color_dialog)
             }