fix(control): capture after the next rendered frame

src/app/view/mod.rs

@@ -2606,6 +2606,18 @@ impl OpenCADStudio {
         } else {
             Subscription::none()
         };
+        // C11: park a `capture` request until the window draws another frame;
+        // a timer fallback prevents a request from hanging when no redraw is
+        // pending.
+        let capture_frame = if self.control.capture_frame_pending {
+            Subscription::batch([
+                window::frames().map(|_| Message::ControlCaptureFrame { redrew: true }),
+                iced::time::every(std::time::Duration::from_millis(50))
+                    .map(|_| Message::ControlCaptureFrame { redrew: false }),
+            ])
+        } else {
+            Subscription::none()
+        };
         // Blink the MText preview caret while the editor is open.
         let caret_blink = if self.mtext_editor.is_some() {
             iced::time::every(std::time::Duration::from_millis(530))
@@ -2860,6 +2872,7 @@ impl OpenCADStudio {
             nav_settle,
             gpu_probe,
             thumbnail_capture,
+            capture_frame,
             caret_blink,
             web_fonts,
             autosave,