feat: Many more improvements to video player now with a subscription

crates/iced-video/src/source.rs

@@ -18,6 +18,7 @@ pub struct VideoSource {
     pub(crate) bus: Bus,
     pub(crate) ready: Arc<AtomicBool>,
     pub(crate) frame: Arc<Mutex<gst::Sample>>,
+    pub(crate) size: std::sync::OnceLock<(i32, i32)>,
 }
 
 impl VideoSource {
@@ -79,15 +80,17 @@ impl VideoSource {
             bus,
             ready,
             frame,
+            size: std::sync::OnceLock::new(),
         })
     }
 
-    pub async fn wait(self) -> Result<()> {
+    pub async fn wait(&self) -> Result<()> {
         self.playbin
             .wait_for_states(&[gst::State::Paused, gst::State::Playing])
             .await
             .change_context(Error)
-            .attach("Failed to wait for video initialisation")
+            .attach("Failed to wait for video initialisation")?;
+        Ok(())
     }
 
     pub fn is_playing(&self) -> Result<bool> {
@@ -126,14 +129,20 @@ impl VideoSource {
     }
 
     pub fn size(&self) -> Result<(i32, i32)> {
+        if let Some(size) = self.size.get() {
+            return Ok(*size);
+        }
         let caps = self
             .appsink
             .sink("sink")
             .current_caps()
             .change_context(Error)?;
-        caps.width()
+        let out = caps
+            .width()
             .and_then(|width| caps.height().map(|height| (width, height)))
             .ok_or(Error)
-            .attach("Failed to get width, height")
+            .attach("Failed to get width, height")?;
+        self.size.set(out);
+        Ok(out)
     }
 }