


     XLITO(1)		   UNIX	5.0 (7 Jul 1993)	      XLITO(1)



     NAME
	  xlito	(XLoadImageTrailingOptions) - Append/Delete/Show a
	  Trailing Option string in a file.

     SYNOPSIS
	  xlito	[option] [string] files	...

     DESCRIPTION
	  xlito	(XLoadImageTrailingOptions) is a utility that provides
	  a file format	independent way	of marking image files with
	  the appropriate options to display correctly.	 It does this
	  by appending to a file, a string specified by	the user. The
	  string is marked with	some magic numbers so that it can be
	  extracted by a program that knows what to look for. Since
	  almost all image files have some sort	of image dimension
	  information in the file, the programs	that load or
	  manipulate these files generally do not look beyond the
	  point	at which they have read	the complete image, so
	  trailing information is safely be hidden. If appending this
	  information causes trouble with other	utilities, it can
	  simply be deleted.

	  Appropriate version of xloadimage (ie. xli 1.00) will
	  recognise these trailing options at the end of the image
	  files, and will treat	the embedded string as if it were a
	  sequence of command line Image Options.  Any Global Options
	  will be ignored, and unlike command line image Options,
	  Trailing Options are never propagated	to other images.

	  Old versions of xloadimage (3.01 or less) can	be made
	  forward compatible by	using the -x option to pull the
	  trailing options out of the image files, and put them	on the
	  command line where xloadimage	can see	them.

     OPTIONS
	  The default behavior is to display the trailing option
	  strings (if any) of the files	on the argument	line.  The
	  following options change the behavior	of xlito:

	  -c option_string file_name ...
		  This adds or changes the embedded string to
		  option_string. The string will have to be quoted if
		  it is	composed of more than one word.

	  -d file_name ...
		  Delete any embedded trailing option strings in the
		  given	files.

	  -x file_name ...
		  Process the files and	create a command line string
		  suitable for use by xloadimage. Arguments starting
		  with - are echoed, arguments not starting with - are



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     XLITO(1)		   UNIX	5.0 (7 Jul 1993)	      XLITO(1)



		  treated as files and any trailing options strings
		  are echoed followed by the file name.	The xloadimage
		  option -name is treated correctly.

     EXAMPLES
	  If fred.gif has the wrong aspect ratio, then it might	need
	  viewing with the xloadimage options:

	       xloadimage -yzoom 130 fred.gif

	  This option can then be appended to the file by:

	       xlito -c	"-yzoom	130" fred.gif

	  and from then	on some	new versions of	xloadimage will	get
	  the appropriate options from the image file itself. Old
	  versions of xloadimage can be	made to	work by	using:

	       xloadimage `xlito -x fred.gif`

	  This can be made transparent by using	a script containing
	  something like:

	       xloadimage `xlito -x $*`

	  The script could be called xli for instance.

	  The options can be deleted with:

	       xlito -d	fred.gif

     AUTHOR
	  Graeme Gill
	  Labtam Australia
	  graeme@labtam.oz.au

     COMPATIBILITY WITH	IMAGE FILES
	  Some image files are actually	ascii files that are used in
	  other	contexts.  X Bitmap files are an example. They are
	  formatted as 'C' style #defines and an initialised array of
	  characters, so that they can be included in 'C' source code.
	  Adding trailing options would	therefore render the file
	  unusable with	a compiler, since it will get a	syntax error
	  on the railing option	string and the magic numbers. The
	  solution to this is that xlito will ignore a certain amount
	  (a few hundred bytes)	after the trailing options, and	uses a
	  padding of 20	bytes before the trailing options. These two
	  areas	will be	maintained when	changing an existing trailing
	  option. In the case of an X bitmap then, the solution	is to
	  edit the file	and place the embedded string in some 'C'
	  comments:




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     XLITO(1)		   UNIX	5.0 (7 Jul 1993)	      XLITO(1)



	  eg: say the file starts as:
	  #define tt_width 4
	  #define tt_height 4
	  static char tt_bits[]	= {
	     0x08, 0x02, 0x04, 0x01};

	  and you add a	trailing options:
	  #define tt_width 4
	  #define tt_height 4
	  static char tt_bits[]	= {
	     0x08, 0x02, 0x04, 0x01};
	  01234567890123456789XXX xloadimage trailing options
	  XXX0007"-smooth"0007XXX
	  xloadimage trailing options XXX

	  Then the trailing options can	be commented out:
	  #define tt_width 4
	  #define tt_height 4
	  static char tt_bits[]	= {
	     0x08, 0x02, 0x04, 0x01};
	  /*234567890123456789XXX xloadimage trailing options
	  XXX0007"-smooth"0007XXX
	  xloadimage trailing options XXX */

     BUGS
	  xlito	doesn't	cope with compressed files. A files will need
	  uncompressing, the options added, and	then compressing
	  again.



























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