begin et end frame dans context

lib/error.rs

@@ -50,4 +50,29 @@ pub enum WsgError {
     /// Caller: `Context::configure()` when selecting a render format/alpha mode from surface capabilities.
     #[error("No compatible render format or alpha mode found for the surface")]
     SurfaceIncompatible,
+
+    /// A timeout was encountered while acquiring a surface texture. Skip this frame and retry.
+    #[error("Frame acquisition timed out")]
+    FrameTimeout,
+
+    /// The window is occluded (minimized or behind another window). Skip until visible.
+    #[error("Window is occluded")]
+    Occluded,
+
+    /// The underlying surface changed — call configure() before retrying.
+    #[error("Surface configuration outdated; reconfigure required")]
+    Outdated,
+
+    /// The surface has been lost and needs to be recreated.
+    #[error("Surface lost")]
+    Lost,
+
+    /// A validation error inside get_current_texture() was raised.
+    #[error("Validation error during frame acquisition")]
+    Validation,
+
+    /// Successfully acquired the surface texture but it no longer matches the surface properties.
+    /// Reconfigure recommended for optimal performance.
+    #[error("Acquired suboptimal surface texture; reconfigure recommended")]
+    SuboptimalTexture,
 }