pro xgetdistance,x0=x0,y0=y0,x1=x1,y1=y1,ds=ds

;+
; XGETDISTANCE
;
; xgetdistance 
;
;-
common active,active

device, get_graphics = old, set_graphics = 6  ;Set xor
col = (!d.n_colors/2)

!err=0
while (!err ne 1) do begin
   cursor,x0,y0,/change
   wait,0.3
   endwhile

x1=x0+1
y1=y0+1
plots,[x0,x1],[y0,y1],/data,col=col

tvcrs,x1,y1,/data
change_start=1

; Get out when the right button is pushed

repeat begin
   cursor,x,y,/change
   case !err of

      0: begin				; No buttons - move the current end
         wait,0.1
	 plots,[x0,x1],[y0,y1],/data,col=col
         if(change_start) then begin
            x1=x & y1=y
         endif else begin
            x0=x & y0=y
         endelse
	 plots,[x0,x1],[y0,y1],/data,col=col
         endcase

      1: begin				; Left Button - Toggle change_start
	 if (change_start) then begin
	    change_start=0
	    tvcrs,x0,y0,/data
         endif else begin
	    change_start=1
	    tvcrs,x1,y1,/data
	 endelse
	 wait,0.3
	 endcase

      2:
      4: 				; Right button

   endcase
endrep until (!err eq 4)

device,set_graphics=old

ds=sqrt((x1-x0)^2 + (y1-y0)^2)
print,'(X,Y)_0 = ',x0,y0,'  (X,Y)_1 = ',x1,y1,'  DS = ',ds
end