static void signal_show_as_gray(GtkWidget *w, gpointer data)
{
    IMAGE *img= (IMAGE *)data;
    img->devicen_gray= !img->devicen_gray;
    display_sync(img->handle, img->device);
}
static void signal_show_as_gray(GtkWidget *w, gpointer data)
{
    IMAGE *img= (IMAGE *)data;
    img->devicen_gray= !img->devicen_gray;
    display_sync(img->handle, img->device);
}