// Redraws the refresh_frame
virtual void draw_refresh(int flush = 1) {};
virtual void clear(int flash=1);
+// draw scope
+ virtual int scope_on() { return 0; }
+ virtual void draw_scope(VFrame *frame, int refresh) {}
+ void process_scope(VideoDevice *video, VFrame *frame);
// Get top left offset of canvas relative to output.
// Normally negative. Can be positive if output is smaller than canvas.