subroutine event_display_ypixels_to_lab(xpixel, ypixel, x,y,z)
c
c This routine takes x,y for a display pixel and returns telescope coordinates
c for the y view.
c Keep in mind that X11 uses increasing x to move to the right, increasing 
c y to move down on the screen.
c
c
c George Gollin, g-gollin@uiuc.edu, 1999.
c
c
#include "event_display.inc"
c
c *************************************************************************
c
      x=0.
c
      y=(pixel_at_y_0 - ypixel) / pixels_per_y
     .     +  telescope_min_y
c
      z=(xpixel - pixel_at_zy_0) / pixels_per_zy
     .     +  telescope_min_zy
c
c
      return
      end