subroutine event_display_button_query(
     .     ixmouse, iymouse, mouse_button, in_button)
c
c **********************************************************************
c
c figure out if a mouse click just received was in one of my display control
c buttons. return 0 if not, and button number if yes. Input arguments
c are x and y of pixel, and mouse button if mouse was clicked.
c
c George Gollin, CPPM (Marseille) and univerisyt of Illinois (Urbana-Champaign)
c g-gollin@uiuc.edu, 1999
c
c **********************************************************************
c
c include files holding common blocks and parameter statements go here:
c note that they're in the same directory as this file.
c
#include "event_display.inc"
c
c **********************************************************************
c
c non-common type definitions and array definitions go here:
c
c **********************************************************************
c
c data statements go here:
c
c **********************************************************************
c
c
c store the info about the previously detected mouse event if we got a click
c this time:
      if(mouse_button .ge. 1 .and. mouse_button .le. 3) then
         iprevious_mouse_button=icurrent_mouse_button
         iprevious_button=icurrent_button
         iprevious_click_pixel_x=icurrent_click_pixel_x
         iprevious_click_pixel_y=icurrent_click_pixel_y
c
c update the current mouse button info:
         icurrent_mouse_button=mouse_button
         icurrent_click_pixel_x=ixmouse
         icurrent_click_pixel_y=iymouse
c
         end if
c
c in any case, store the sample pixel information:
      iprevious_sample_pixel_x=icurrent_sample_pixel_x
      iprevious_sample_pixel_y=icurrent_sample_pixel_y
      icurrent_sample_pixel_x=ixmouse
      icurrent_sample_pixel_y=iymouse

c now see if the position is inside one of my buttons...
      in_button=-99
c
      if(number_of_buttons .gt. 0) then
         x=ixmouse
         y=iymouse
         do i=1,number_of_buttons
         if(x .ge. button_left(i)  .and.
     .      x .le. button_right(i) .and.
     .      y .ge. button_top(i)   .and.
     .      y .le. button_bot(i)          )  then
c
            in_button=i
            go to 99
            end if
         end do
c
         end if
c
c
 99   continue
c
c
c only update the variable in common if we got a mouse click...
      if(mouse_button .ge. 1 .and. mouse_button .le. 3)
     .     icurrent_button=in_button
c
c
      return
      end