/*******************************************************************************
*
* McStas, neutron ray-tracing package
*         Copyright (C) 1997-2011, All rights reserved
*         Risoe National Laboratory, Roskilde, Denmark
*         Institut Laue Langevin, Grenoble, France
*
* Component: ScanningSlit
*
* %I
* Written by: Jochen Stahn, based on the Slip component by
*             Kim Lefmann and Henrik M. Roennow
* Date: 15. 10. 2013
* Version: $Revision: 0.00 $
* Origin: PSI
* Release: McStas 1.12c
*
* moving rectangular slit with optional insignificance cut
*
* %D
* A simple rectangular slit, where the blades in x-direction move with time.
* No transmission around the slit is allowed.
* If cutting option is used, low-weight neutron rays are ABSORBED
*
* Example: FastSlit(height=0.1)
*
* %P
* INPUT PARAMETERS
*
* height: height of the opening in y, centered.
*
* Optional parameters:
* cut:  Lower limit for allowed weight (1)
*
* %E
*******************************************************************************/


DEFINE COMPONENT ScanningSlit
DEFINITION PARAMETERS ()
SETTING PARAMETERS (xmin=0, xmax=0, ymin=0, ymax=0, height=0.1, dist=2.4, lmin=4, lmax=10, omeg=0, eps=1.25, reso=0.01, dthet=1.5, posi=33.7)
OUTPUT PARAMETERS ()
/* STATE PARAMETERS (x,y,z,vx,vy,vz,t,s1,s2,p) */

DECLARE
 %{
  double lact;
 %}


INITIALIZE
%{
  if (height > 0) { ymax=height/2; ymin=-ymax; }
  lmax  *= (1+reso/2) ;
  lmin  *= (1-reso/2) ;
  eps   *= PI/180 ;
  omeg  *= PI/180 ;
  dthet *= PI/180;
%}

TRACE
%{
    PROP_Z0;
    lact = 3.956e3*t/posi ;
    xmin = -dist * (1+reso/2)*( eps + 0.5*dthet - dthet*(lact-lmin)/(lmax-lmin) ) ;
    xmax = -dist * (1-reso/2)*( eps + 0.5*dthet - dthet*(lact-lmin)/(lmax-lmin) ) ;
    if ((x<xmin || x>xmax || y<ymin || y>ymax))
      ABSORB;
    else
      SCATTER;
%}

MCDISPLAY
%{
  magnify("xy");
    double xw, yh;
    xw = (xmax - xmin)/2.0;
    yh = (ymax - ymin)/2.0;
    multiline(3, xmin-xw, (double)ymax, 0.0,
              (double)xmin, (double)ymax, 0.0,
              (double)xmin, ymax+yh, 0.0);
    multiline(3, xmax+xw, (double)ymax, 0.0,
              (double)xmax, (double)ymax, 0.0,
              (double)xmax, ymax+yh, 0.0);
    multiline(3, xmin-xw, (double)ymin, 0.0,
              (double)xmin, (double)ymin, 0.0,
              (double)xmin, ymin-yh, 0.0);
    multiline(3, xmax+xw, (double)ymin, 0.0,
              (double)xmax, (double)ymin, 0.0,
              (double)xmax, ymin-yh, 0.0);
%}

END