Ppmtopcx User Manual(0) Ppmtopcx User Manual(0)
ppmtopcx - convert a PPM image to a PCX file
This program is part of Netpbm(1).
ppmtopcx reads a PPM image as input and produces a PCX file as output.
The type of the PCX file depends on the number of colors in the pixmap:
16 colors or fewer:
1 bit/pixel, 1-4 planes.
more than 16 colors, but no more than 256:
8 bits/pixel, 1 plane, colormap at the end of the file.
More than 256 colors:
24bit truecolor file (8 bits/pixel, 3 planes).
You can override some of that and explicitly choose the format with the
-24bit Produce a 24bit truecolor PCX file, even if the image has 256
colors or fewer.
-8bit Produce an 8bit (256 colors) PCX file, even if the image has 16
colors or fewer.
This option was added in Netpbm 10.18 (August 2003).
Use ’packed pixel’ format for files with 16 colors or fewer: 1,
2, or 4 bits/pixel, 1 plane.
Instead of computing a palette from the colors in the image, use
a standard, built-in 16 color palette. If the image contains a
color that is not in the standard palette, ppmtopcx fails.
The standard palette is not only a set of colors, but a specific
mapping of palette indexes to colors. E.g. red is 4.
You can use pnmremap with a suitable PPM image of the standard
palette to adapt your image to use exactly those colors in the
palette so that ppmtopcx -stdpalette will work on it.
The file pcxstd.ppm, part of Netpbm, contains the standard
Although the PCX header tells exactly what palette is used in
the file, some older PCX interpreters do not use that informa-
tion. They instead assume the standard palette. If you don’t
use the -stdpalette option, ppmtopcx, ppmtopcx may create an
image that uses a different palette (a rearrangement of the same
colors) and then one of these older interpreters would interpret
the colors in the image wrong.
You cannot specify this option along with -palette.
This option was new in Netpbm 10.22 (April 2004).
Instead of computing the palette from the colors in the image,
use the palette from the file palettefile. If the palette con-
tains a color that is not in that palette, ppmtopcx fails.
The palette file must be a PPM image that contains one pixel for
each color in the palette. It doesn’t matter what the aspect
ratio of the palette image is. The order of the colors in the
PCX palette is the order of the pixels in the PPM image in stan-
dard western reading order (left to right, top to bottom). If
there is a duplicate color in the palette, ppmtopcx chooses
between them arbitrarily in building the PCX raster.
You would need this only if you have a PCX reader that can’t
read the palette that is in the PCX file and instead assumes
some particular palette. See also the -stdpalette option.
If your input image might contain colors other than those in
your palette, you can convert the input image to one that con-
tains only those colors in your palette with pnmremap.
You cannot specify this along with -stdpalette.
This option was new in Netpbhm 10.25 (October 2004).
Generate a PCX file with planes planes, even though the number
of colors in the image could be represented in fewer. This
makes the file larger, but some PCX interpreters are capable of
processing only certain numbers of planes.
This is meaningful only when ppmtopcx generates an image in the
16 color palette format without packed pixels. Consequently,
you cannot specify this option together with -24bit or -8bit or
The valid values for planes are 1, 2, 3, and 4. By default,
ppmtopcx chooses the smallest number of planes that can repre-
sent the colors in the image. E.g. if there are 5 colors, ppm-
topcx chooses 3 planes.
This option was new in Netpbm 10.21 (March 2004).
These options set the position of the image in some field (e.g.
on a screen) in columns to the right of the left edge and rows
below the top edge. The PCX format contains image position
information. Don’t confuse this with the position of an area of
interest within the image. For example, using pnmpad to add a
10 pixel left border to an image and then converting that image
to PCX with xpos = 0 is not the same as converting the original
image to PCX and setting xpos = 10.
The values may be from -32767 to 32768.
The default for each is zero.
Copyright (C) 1994 by Ingo Wilken (Ingo.Wilken@informatik.uni-olden-
Based on previous work by Michael Davidson.
netpbm documentation 27 March 2004 Ppmtopcx User Manual(0)
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