set_viewer

(tmp_for_tar/imgio/set_viewer.m)

Function Synopsis

vc = set_viewer( vc )

Help text

       vc2 = set_viewer( [vc] )

 vc : Either of

       string : Viewer command, of the form "viewer_name options", to
                which a stream of pnm data can be sent. Checks whether it
                the viewer exists with the "which" command. If it does,
                sets the global variable  image_viewer  is set to  vc.

       number : returns list of known viewers.

 If no argument is given, checks for some standard viewers and sets the
 global variable  image_viewer  to the first one that is found to exist.

 vc2 is either the first viewer command that was found to work or the
 empty string if none has been found.

 The global variable  image_viewer  is set only if a working viewer was
 found. 

 Last modified: Setembro 2002

Listing of function file tmp_for_tar/imgio/set_viewer.m

##       vc2 = set_viewer( [vc] )
##
## vc : Either of
##
##       string : Viewer command, of the form "viewer_name options", to
##                which a stream of pnm data can be sent. Checks whether it
##                the viewer exists with the "which" command. If it does,
##                sets the global variable  image_viewer  is set to  vc.
##
##       number : returns list of known viewers.
##
##
## If no argument is given, checks for some standard viewers and sets the
## global variable  image_viewer  to the first one that is found to exist.
##
## vc2 is either the first viewer command that was found to work or the
## empty string if none has been found.
## 
## The global variable  image_viewer  is set only if a working viewer was
## found. 


## Author:        Etienne Grossmann  <etienne@isr.ist.utl.pt>
## Last modified: Setembro 2002

function vc = set_viewer( vc )

  global image_viewer = "" ;
  
  ## List of image viewer commands. Add your own, if you want. 
  def = ["xv -";\
	 "display -";\
	 "xloadimage stdin > /dev/null"];

  if nargin != 0 , 
    
    if isstr (vc)
      ## Try only user-provided viewer
      def = vc ;
    else
      vc = def ;
      return 
    end
  end
  ## Try available viewers until one works
  for i = 1:rows (def), 
				# vc = viewer's command
    vc = deblank (def(i,:));	
    ## printf ("set_viewer : Trying '%s'\n",vc)
    
    fb = min (find (vc==" ")); # First blank
    
				# vn = viewer's name
    if ! isempty (fb), vn = vc(1:fb-1);
    else               vn = vc ;
    end
    
				# Return 0 means success
    ## if !  system (["which ",vn," > /dev/null"]) (2),
    [dum,status] = system (["which ",vn," > /dev/null"]);
    if !  status ,
      image_viewer = vc ;
      return ;
    end
  end
  image_viewer = vc = "" ;

endfunction