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XLITO(1)		     General Commands Manual			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 dis-
     play 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 pro-
     grams 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 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

MAINTAINER
     smar@reptiles.org

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 unus-
     able  with  a compiler, since it will get a syntax error on the railing op-
     tion 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 embed-
     ded string in some 'C' comments:

     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.

				   7 Jul 1993				XLITO(1)

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