if(mouse_check_button_pressed(mb_middle))
{
    xs = window_mouse_get_x();
    ys = window_mouse_get_y();
}
if(mouse_check_button(mb_middle))
{
    xe= window_mouse_get_x();
    ye= window_mouse_get_y();
    view_xview[0] += xs-xe
    view_yview[0] += ys-ye
    xs = xe;
    ys = ye;
}

if mouse_wheel_up(){
    if(view_wview[0] >= 480){
        view_hview[0] -= 27
        view_wview[0] -= 48
    }
}else if mouse_wheel_down(){
    if(view_wview[0] <= 6400){
        view_hview[0] += 27
        view_wview[0] += 48
    }
}