;+
; NAME:
;  tv2im
; PURPOSE: (one line)
;  Write the contents of a window or device to a graphics file
; CATEGORY:
;  Graphics
; CALLING SEQUENCE:
;  tv2im, filename
; INPUTS:
;  filename : A string containing the name of file to be written.
; KEYWORD PARAMETERS:
;  corner : if set, attempt to set the lower right corner (15x15 pixels) to the
;    background color
;  true : if set, save in true color
;  flip : if set, flip vertically before saving.
; MODIFICATION HISTORY:
;  Written 2012 Mar 9, by Leslie Young, SwRI
;  2016 Mar 22 LAY. Added header documentation.
;-
pro tv2im, fn, corner=corner, true=true, flip=flip

    tv = tvrd(true=true)
    if keyword_set(true) then begin
        nxnyn,tv,nc,nx,ny
        if keyword_set(corner) then begin
            v = tv[*,0:14,0:14]
            tv[*,nx-15:nx-1,0:14] = v
        end
    endif else begin
        nxnyn,tv,nx,ny
        if keyword_set(corner) then begin
            v = tv[0,0]
            tv[nx-15:nx-1,0:14] = v
        end
    endelse

    if keyword_set(flip) then begin
       if keyword_set(true) then begin
          tv = reverse(tv,3)
       endif else begin
          tv = reverse(tv,1)
       endelse
    endif

    wrim, fn, tv

end