opencv/highgui.go
func (win *Window) GetTrackbarPos(name string) (value, max int) {
	rv := C.cvGetTrackbarPos(win.trackbarName[name], win.name_c)
	return int(rv), win.trackbarMax[name]
}
func (win *Window) GetTrackbarPos(name string) (value, max int) {
	rv := C.cvGetTrackbarPos(win.trackbarName[name], win.name_c)
	return int(rv), win.trackbarMax[name]
}
/* retrieve or set trackbar position */