;+
; NAME:
;	SMEI_SEQUENCE::SET_SHIFT
;
;
; PURPOSE:
;	To set the shift factor for showing a smei sequence.
;
;
; CATEGORY:
;	SMEI_SEQUENCE
;
;
; CALLING SEQUENCE:
;	seqref -> set_shift, shift
;
;
; INPUTS:
;	shift	int	Set the shift in right-angles for displaying
;			rectangular projection images.
;
;
; KEYWORD PARAMETERS:
;	/north	Make the central axis North (shift=0)
;	/east	Make the central axis East (shift=1)
;	/south	Make the central axis South (shift=2)
;	/west	Make the central axis West (shift=3)
;
;
; MODIFICATION HISTORY:
;	Original: 28/7/03; SJT
;-

pro smei_sequence::set_shift, shift, north = north, east = east, south $
                 = south, west = west

if n_params() eq 0 then case 1 of
    keyword_set(north): shift = 0
    keyword_set(east): shift = 1
    keyword_set(south): shift = 2
    keyword_set(west): shift = 3
    else: begin
        smei_msg, /warn, "Must specify a shift or an axis keyword"
        return
    end
endcase
if shift lt 0 or shift ge 4 then begin
    smei_msg, /warn, "Shift out of range"
    return
endif

self.options.pa_shift = shift
self -> mk_pixmap, /clear

end