SGI Hot Mix 17/Hot Mix 17.iso/HM17_SGI/research/lib/zoom.pro

Text File | 1997-07-08 | 5KB | 170 lines

; $Id: zoom.pro,v 1.8 1997/01/15 03:11:50 ali Exp $

pro zoom,xsize=xs, ysize=ys, fact = fact, interp = interp, continuous = cont, $
        keep=keep, zoom_window=zoom_win, new_window=new_win
;+
; NAME:
;    ZOOM
;
; PURPOSE:
;    Display part of an image (or graphics) from the current window
;    enlarged in another window.
;
;    The cursor is used to mark the center of the zoom.
;
; CATEGORY:
;    Image display.
;
; CALLING SEQUENCE:
;    ZOOM [, FACT = Fact, /INTERP, XSIZE = Xs, YSIZE = Ys, /CONTINUOUS, $
;        /KEEP, ZOOM_WINDOW=Zoom_Win, /NEW_WINDOW ]
;
; INPUTS:
;    All input parameters are passed as keywords.
;
; KEYWORDS:
;    FACT:    Zoom factor.  This parameter must be an integer.  The default
;        zoom factor is 4.
;
;    INTERP:    Set this keyword to use bilinear interpolation, otherwise
;        pixel replication is used.
;
;    XSIZE:    The X size of the zoom window.  The default is 512.
;
;    YSIZE:    The Y size of the zoom window.  The default is 512.
;
;   CONTINUOUS:    Set this keyword to make the zoom window track the mouse
;        without requiring the user to press the left mouse button.
;        This feature only works well on fast computers.
;
;         KEEP: Keep the zoom window after exiting the procedure.
;
;  ZOOM_WINDOW:    When used with KEEP, returns the index of the zoom window.
;        Otherwise, if KEEP is not set, then -1 is returned.
;
;   NEW_WINDOW:    Normally, if ZOOM is called with /KEEP and then called again,
;        it will use the same window to display the zoomed image.
;        Calling ZOOM with /NEW_WINDOW forces it to create a new window
;        for this purpose.
;
; OUTPUTS:
;    No explicit outputs.   A new window is created if necessary. It
;    is destroyed upon exit if KEEP is not specified.
;
; COMMON BLOCKS:
;    None.
;
; SIDE EFFECTS:
;    A window is created/destroyed.
;
;    When ZOOM is reusing a zoom window from a previous call to ZOOM,/KEEP,
;    then the XSIZE and YSIZE parameters are reset to the actual size of the
;    window.
;
; RESTRICTIONS:
;    ZOOM only works with color systems.
;
; PROCEDURE:
;    Straightforward.
;
; MODIFICATION HISTORY:
;    ?
;       William Thompson, March 1992, added common block ZOOM_WINDOW
;        and KEEP keyword.
;    William Thompson, 20 May 1993, added ZOOM_WINDOW and NEW_WINDOW
;        keywords.
;
;-
on_error,2              ;Return to caller if an error occurs
common zoom_window, zoom_w
;
if n_elements(xs) le 0 then xs = 512
if n_elements(ys) le 0 then ys = 512
if n_elements(fact) le 0 then fact=4
if keyword_set(cont) then waitflg = 2 else waitflg = 3
ifact = fact
old_w = !d.window
if keyword_set(new_win) then zoom_w = -1    ;Don't use old window (if any)
if n_elements(zoom_w) eq 0 then zoom_w = -1        ;No zoom window yet
;
;  If an old window is to be used, then make sure it still exists.  (Added by
;  William Thompson, 20 May 1993.)
;
if zoom_w ge 0 then begin
    device, window_state=win_state
    if not win_state[zoom_w] then zoom_w = -1
endif
;
;  Make sure the parameters xs and ys agree with the size of the window, in
;  case a window is being reused from a previous call to ZOOM,/KEEP.  (Added by
;  William Thompson, 20 May 1993.)
;
IF ZOOM_W GE 0 THEN BEGIN
    OLD_WINDOW = !D.WINDOW
    WSET, ZOOM_W
    XS = !D.X_SIZE
    YS = !D.Y_SIZE
    WSET, OLD_WINDOW
ENDIF
tvcrs,1            ;enable cursor
ierase = 0        ;erase zoom window flag
IF KEYWORD_SET(cont) THEN BEGIN
    PRINT,'Cursor position is zoom center, '+$
          'Middle button for new zoom factor, Right button to quit'
ENDIF ELSE BEGIN
    PRINT,'Left for zoom center, Middle for new zoom factor, Right to quit'
ENDELSE
again:
    cursor,x,y,waitflg,/dev    ;Wait for change
    case !err of
4:    goto, done
2:    if !d.name eq 'SUN' or !d.name eq 'X' then begin    ;Sun view?
        s  = ['New Zoom Factor:',strtrim(indgen(19)+2,2)]
        ifact = wmenu(s, init=ifact-1,title=0)+1
        IF (!Version.Os NE 'MacOS') THEN $
            tvcrs,x,y,/dev $    ;Restore cursor
                ELSE tvcrs,1
        ierase = 1
    endif else begin
        Read,'Current factor is',ifact+0,'.  Enter new factor: ',ifact
        if ifact le 0 then begin
            ifact = 4
            print,'Illegal Zoom factor.'
            endif
            ierase = 1    ;Clean out previous display
    endelse
else:    begin
    x0 = 0 > (x-xs/(ifact*2))     ;left edge from center
    y0 = 0 > (y-ys/(ifact*2))     ;bottom
    nx = xs/ifact            ;Size of new image
    ny = ys/ifact
    nx = nx < (!d.x_vsize-x0)
    ny = ny < (!d.y_size-y0)
    x0 = x0 < (!d.x_vsize - nx)
    y0 = y0 < (!d.y_vsize - ny)
    a = tvrd(x0,y0,nx,ny)        ;Read image
    if zoom_w lt 0 then begin    ;Make new window?
        window,/free,xsize=xs,ysize=ys,title='Zoomed Image'
        zoom_w = !d.window
    endif else begin
        wset,zoom_w
        if ierase then erase        ;Erase it?
        ierase = 0
    endelse
    xss = nx * ifact    ;Make integer rebin factors
    yss = ny * ifact
    tv,rebin(a,xss,yss,sample=1-keyword_set(interp))
    wset,old_w
    endcase
endcase
goto,again

done:
IF NOT KEYWORD_SET(KEEP) THEN BEGIN
        if zoom_w ge 0 then wdelete,zoom_w              ;Done with window
        ZOOM_W = -1
ENDIF
zoom_win = zoom_w    ;Return index of zoom window to user
end