.\" Manual page for xcf2pnm
.\" Copyright (C) 2006  Henning Makholm
.\"
.\" This program is free software; you can redistribute it and/or modify
.\" it under the terms of version 2 of the GNU General Public License as
.\" published by the Free Software Foundation.
.\"
.\" This program is distributed in the hope that it will be useful,
.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
.\" GNU General Public License for more details.
.\"
.\" You should have received a copy of the GNU General Public License
.\" along with this program; if not, write to the Free Software
.\" Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
.TH xcf2pnm 1 2006-02-12 "Xcftools" ""
.SH NAME
xcf2pnm \- convert from GIMP xcf files to ppm/pgm/pbm format
.ds p xcfinfo
.SH SYNOPSIS
.B \*p
[
.I options
]
.I filename
[
.I layer names
]
.SH DESCRIPTION
.B xcf2pnm
is a command-line tool that converts image files in the XCF format used by
.BR gimp (1)
to the generic image formats
.BR pbm (5),
.BR pgm (5),
and
.BR ppm (5),
flattening layers if necessary. It does not need to have
the Gimp engine itself available.
.SH GENERAL OPTIONS
.so xcf2pnm.1i
.P
Several groups of options are mutually incompatible; in each group the
one given last will win:
.TP 4
1)
.B \-A
and
.BR \-b .
.TP
2)
.BR \-c ,
.BR \-g ,
.BR \-m ,
and
.BR \-n .
.TP
3)
.B \-D
and
.BR \-G .
.TP
4)
.BR \-j ,
.BR \-z ,
and
.BR \-Z .
.TP
5)
.B \-C
and
.BR \-O / \-S .
.SH LAYER SPECIFICATIONS
If no
.I layer name
is given on the command line, all of the visible layers in
the XCF file are merged to produce the output image.
It is also possible to specify the layers to merge explicitly,
by giving their names as separate arguments after the
input filename. In that case, the output will contain
.I only
the named layers. The layers will be merged in the order
they appear on the command line, with the leftmost being
"at the bottom" \- that is, the layer ordering in the XCF file
will be ignored.
.P
The following options can be given
.I after
a layer name to override the global properties of the layer:
.so xcf2pnm.1il
.so exit.1i
.SH EXAMPLES
.IP
.B xcf2pnm -b white foo.xcf > foo.ppm
.IP
.B xcf2pnm -a footrans.pgm -o foo.ppm foo.xcf Layer1 Layer2
.P
To test whether the flattened image has any transparency, use
.IP
.B xcf2pnm foo.xcf > /dev/null
.P
To test whether the flattened image has
.I partially
transparent pixels, use
.IP
.B xcf2pnm -b white -G > /dev/null
.SH BUGS AND LIMITATIONS
.P
When several partially transparent layers are merged, the pixel
values are interpolated without gamma correction. (The Gimp also
does it this way). Some slight rounding errors in the interpolation
are inevitable;
.B \*p
sometimes has different rounding errors than the Gimp itself,
especially when more than two layers are involved, or in case of
some of the more exotic layer modes.
These differences are usually not visible to the eye.
.P
There are probably other bugs lurking in corner cases. If you discover
one, please notify the author.

.SH FILES
.TP 8
.B /etc/X11/rgb.txt
.TP 8
.B /usr/share/X11/rgb.txt
.TP 8
.B /usr/lib/X11/rgb.txt
Color name database for
.BR \-b .
.SH AUTHOR
.B \*p
was written by Henning Makholm <henning@makholm.net>.
.P
.SH SEE ALSO
.BR xcfinfo (1),
.BR xcf2png (1)