Ubuntu Manpage: ppmtoxpm - convert a portable pixmap into an X11 pixmap

NAME

       ppmtoxpm - convert a portable pixmap into an X11 pixmap

SYNOPSIS

       ppmtoxpm [-name=xpmname] [-rgb=rgb-textfile] [-alphamask=pgmfile] [ppmfile]

       Minimum unique abbrevations are acceptable.

DESCRIPTION

       Reads a portable pixmap as input.  Produces X11 pixmap (version 3) as output which can be loaded directly
       by the XPM library.

       For  example,  to  convert  the file "dot" (found in /usr/include/X11/bitmaps), from xbm to xpm one could
       specify

              xbmtopbm dot | ppmtoxpm -name dot

       or, with a rgb text file (in the local directory)

              xbmtopbm dot | ppmtoxpm -name dot -rgb rgb.txt

OPTIONS

-name=xpmname
The -name option allows you to specify the prefix string which is printed in the resulting XPM
output. If not specified, will default to the filename (without extension) of the <ppmfile>
argument. If you do not specify -name or ppmfile, (i.e. your input is from Standad Input), the
prefix string defaults to the string noname.

rgb=rgb-textfile
The -rgb option allows you to specify an X11 rgb text file for the lookup of color name mnemonics.
This rgb text file is typically the /usr/lib/X11/rgb.txt of the MIT X11 distribution, but any file
using the same format may be used. When specified and a RGB value from the ppm input matches a
RGB value from the <rgb-textfile>, then the corresponding color name mnemonic is printed in the
XPM's colormap. If you don't specify -rgb or if the RGB values don't match, then ppmtoxpm
produces the color specifications in the #RGB, #RRGGBB, #RRRGGGBBB, or #RRRRGGGGBBBB hexadecimal
format.

-alphamask=pgmfile
This option names a PGM file to use as an alpha (transparency) mask. The file must contain an
image the same dimensions as the input image. ppmtoxpm marks as transparent any pixel whose
position in the alpha mask image is at most half white.

If you don't specify -alphamask, ppmtoxpm makes all pixels in the output opaque.

ppmcolormask is one way to generate an alpha mask file. You might also generate it by extracting
transparency information from an XPM file with the -alphaout option to xpmtoppm. There are
similar options on other Netpbm converters that convert from formats that include transparency
information too.

LIMITATIONS

       An option to match the closest (rather than exact) color name mnemonic from  the  rgb  text  would  be  a
       desirable enhancement.

       Truncation  of  the  least significant bits of a RGB value may result in nonexact matches when performing
       color name mnemonic lookups.

AUTHOR