Do secondly refresh via a calloop Timer instead of measuring elapsed time

Cargo.lock

@@ -844,6 +844,7 @@ checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
 name = "wl-seasonal-hours-clock"
 version = "0.1.0"
 dependencies = [
+ "calloop",
  "chrono",
  "resvg",
  "serde",

Cargo.toml

@@ -14,3 +14,4 @@ suncalc = "0.4"
 toml = "0.5"
 serde = { version = "1.0", features = ["derive"] }
 xdg = "2.4"
+calloop = "0.9"

src/main.rs

@@ -2,8 +2,8 @@ extern crate smithay_client_toolkit as sctk;
 
 use std::fmt;
 use std::fs;
-use std::time::SystemTime;
 
+use calloop::{timer::Timer, EventLoop};
 use chrono::prelude::{Local, Utc};
 use chrono::TimeZone;
 use chrono::Timelike;
@@ -633,7 +633,7 @@ fn main() {
         None
     };
 
-    let (env, display, mut queue) = sctk::new_default_environment!(SeasonalClock, desktop)
+    let (env, display, queue) = sctk::new_default_environment!(SeasonalClock, desktop)
         .expect("Unable to connect to a Wayland compositor");
 
     let surface = env
@@ -679,28 +679,31 @@ fn main() {
         window.refresh()
     }
 
-    let now = SystemTime::now();
-    let mut last_elapsed = 0;
+    let mut event_loop = EventLoop::<Option<WEvent>>::try_new().unwrap();
+    let handle = event_loop.handle();
+    let source = Timer::new().expect("Failed to create timer event source!");
+    let timer_handle = source.handle();
+    timer_handle.add_timeout(std::time::Duration::from_secs(1), "");
+
+    handle
+        .insert_source(source, |_, timer_handle, event| {
+            timer_handle.add_timeout(std::time::Duration::from_secs(1), "");
+            if event.is_none() {
+                *event = Some(sctk::window::Event::Refresh);
+            }
+        })
+        .unwrap();
+
+    sctk::WaylandSource::new(queue)
+        .quick_insert(handle)
+        .unwrap();
 
     loop {
         // Update every second
-        // TODO: There’s probably a better way to do this…
-        match now.elapsed() {
-            Ok(elapsed) => {
-                let new_elapsed = elapsed.as_secs();
-
-                if new_elapsed != last_elapsed {
-                    need_redraw = true;
-                    last_elapsed = new_elapsed;
-                }
-            }
-            Err(e) => {
-                println!("Error: {:?}", e);
-            }
-        }
         match next_action.take() {
             Some(WEvent::Close) => break,
             Some(WEvent::Refresh) => {
+                redraw(&mut pool, window.surface(), dimensions, &config).expect("Failed to draw");
                 window.refresh();
                 window.surface().commit();
             }
@@ -732,20 +735,7 @@ fn main() {
             }
         }
 
-        if let Some(guard) = queue.prepare_read() {
-            if let Err(e) = guard.read_events() {
-                if e.kind() != ::std::io::ErrorKind::WouldBlock {
-                    eprintln!(
-                        "Error while trying to read from the wayland socked: {:?}",
-                        e
-                    );
-                }
-            }
-        }
-
-        queue
-            .dispatch_pending(&mut next_action, |_, _, _| {})
-            .expect("Failed to dispatch all messages.");
+        event_loop.dispatch(None, &mut next_action).unwrap();
     }
 }