module centermag
    implicit none
!-----------------------------------------------------------------------
!-
!   By definition, the default centermax (0, 0, 1) give us a
!   (-1,-1), (1, 1) box, who is mapped to the screen size.
!-
!-----------------------------------------------------------------------
!      definition of structures
!-
type t_centermag
    integer           :: wscr, hscr      ! "physycal" screen size
    real              :: mag = 1.0       ! magnitude factor
    real              :: cx, cy          ! the center

    integer           :: flag = 0
end type
!-------------------------------------------------------------------
contains
!-------------------------------------------------------------------
subroutine init_centermag(cntmag, w, h, mag)
    type(t_centermag),intent(out)     :: cntmag
    integer, intent(in)               :: w, h        ! screen size
    real, intent(in)                  :: mag

    write(0, *) ">>> init centermag:", w, h

    cntmag%wscr = w   ;   cntmag%hscr = h
    cntmag%mag = mag

end subroutine

!-------------------------------------------------------------------
subroutine  print_centermag (cm)
    type(t_centermag), intent(in)   :: cm

    print *, "Screen     ", cm%wscr, cm%hscr
    print *, "MagFactor  ", cm%mag
    ! print *, "Center     ", cm%cx, cm%cy

end subroutine
!-------------------------------------------------------------------
!-------------------------------------------------------------------
subroutine  centermag_scr2real (sx, sy, rx, ry)
    integer, intent(in)         ::  sx, sy
    real, intent(out)           ::  rx, ry

    print *, 'from scr :', sx, sy

    rx = 999.999
    ry = 666.666

end subroutine
!-------------------------------------------------------------------
subroutine centermag_real2scr (rx, ry, sx, sy)
    real, intent(in)           ::  rx, ry
    integer, intent(out)       ::  sx, sy

    print *, 'from real :', rx, ry

    sx = -1
    sy = -1

end subroutine
!-------------------------------------------------------------------
end module