gl canvas and context

pyui/preview.py

@@ -17,4 +17,9 @@
 from . import preview_generated
 
 class PreviewPanel(preview_generated.PreviewPanel):
-    pass
+
+    def initdialog_event_handler(self, event):
+        self.video_panel.initialize()
+
+    def size_event_handler(self, event):
+        pass