XLITO(1)XLITO(1)NAMExlito (XLoadImageTrailingOptions) - Append/Delete/Show a
Trailing Option string in a file.
SYNOPSISxlito [option] [string] files ...
DESCRIPTIONxlito (XLoadImageTrailingOptions) is a utility that pro
vides 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 util
ities, 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 for
ward compatible by using the -x option to pull the trail
ing 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
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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:
eg: say the file starts as:
#define tt_width 4
#define tt_height 4
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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 */
BUGSxlito doesn't cope with compressed files. A files will
need uncompressing, the options added, and then compress
ing again.
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