Ubuntu Manpage: pnmtopalm - convert a PNM image to a Palm Bitmap

NAME

       pnmtopalm - convert a PNM image to a Palm Bitmap

SYNOPSIS

       pnmtopalm

       [-verbose]

       [-depth=N]

       [-maxdepth=N]

       [-colormap]

       [-transparent=colorspec]

       [-density=N]

       [-offset]

       [-withdummy] [-scanline_compression | -rle_compression | -packbits_compression]

       [pnmfile]

       Minimum  unique  abbreviation of option is acceptable.  You may use double hyphens instead
       of single hyphen to denote options.  You may use white space in place of the  equals  sign
       to separate an option name from its value.

DESCRIPTION

This program is part of Netpbm(1).

pnmtopalm reads a PNM image as input, from Standard Input or pnmfile and produces a Palm
Bitmap as output.

Palm Bitmap files are either grayscale files with 1, 2, or 4 bits per pixel, or mapped
color files with 8 bit per pixel, or a direct color file with 16 bits per pixel, and
pnmtopalm chooses this color depth based on the maxval and number of colors in the input,
unless you specify a depth (bits per pixel) with -depth. You can also specify a maximum
depth with -maxdepth to partially constrain pnmtopalm's choice. Input files must have an
appropriate number and set of colors for the selected output constraints.

This often means that you should run the PNM image through pnmquant or pnmremap before you
pass it to pnmtopalm. Netpbm comes with several colormap files you can use with pnmremap
for this purpose. They are palmgray2.map (4 shades of gray for a depth of 2),
palmgray4.map (16 shades of gray for a depth of 4), and palmcolor8.map (232 colors in
default Palm colormap). In a standard Netpbm installation, these are in the Netpbm data
directory, and you can find the Netpbm data directory with a netpbm-config --datadir shell
command.

Example:

pnmremap myimage.ppm \
-mapfile=$(netpbm-config --datadir)/palmgray2.map \
| pnmtopalm -depth=2 >myimage.palm

Compressed Palm Bitmap files, at least the ones pnmtopalm knows how to create, cannot have
more than 8 bits per pixel. pnmtopalm defaults to 8 bits per pixel if you specify a
compressed output. You can specify the number of bits per pixel explicitly with -depth.
-maxdepth has the same effect as -depth. If you specify more than 8 bits per pixel with
either of these, pnmtopalm fails.

Palm Bitmap Version
pnmtopalm generates a Version 0, 1, 2, or 3 Palm Bitmap. It generates the oldest (lowest)
version it can for the given image and the options you specify.

• If you specify a density (-density option) higher than "low," the version is at
least 3.

• If you specify transparency (-transparent option) or any compression, the version
is at least 2.

• If you specify a custom colormap (-colormap option), the version is at least 1.

• If the image has more than one bit per pixel, the version is at least 1. The image
has more than one bit per pixel if you specify it with -depth or if you let it
default and the image has more than two colors (or shades of gray).

All releases of Palm OS can read a Version 0 bitmap. Palm OS 3.0 and later can read a
Version 1 bitmap. Palm OS 3.5 and later can read a Version 2 bitmap. To read a Version 3
bitmap, you need Palm OS Garnet or a handheld running the High Density Display Feature
Set.

OPTIONS

In addition to the options common to all programs based on libnetpbm (most notably -quiet,
see
Common Options ⟨index.html#commonoptions⟩ ), pnmtopalm recognizes the following command
line options:

-verbose
Display the format of the output file.

-depth=N
Produce a file of depth N, where N must be either 1, 2, 4, 8, or 16. Because the
default Palm 8-bit colormap is not grayscale, if the input is a grayscale or
monochrome image, the output will never be more than 4 bits deep, regardless of the
specified depth. Note that 8-bit color works only in PalmOS 3.5 (and higher), and
16-bit direct color works only in PalmOS 4.0 (and higher). However, the 16-bit
direct color format is also compatible with the various PalmOS 3.x versions used in
the Handspring Visor, so these images may also work in that device.

-maxdepth=N
Produce a file of minimal depth, but in any case less than N bits wide. If you
specify 16-bit, the output will always be 16-bit direct color.

-offset
Set the nextDepthOffset field in the palm file header to indicate the end of the
file (and pad the end of the file to 4 bytes, since nextDepthOffset can point only
to 4 byte boundaries).

A palm image file can contain multiple renditions of the same image, with different
color depths, so a viewer can choose one appropriate for the display. The
nextDepthOffset field tells where in the stream the next rendition begins.

pnmtopalm creates a file that contains only one image, but you can separately
concatenate multiple one-image files to create a multi-image file. If you do that,
you'll need to use -offset so that the resulting concatenation is a correct stream.

By default (if you don't specify -offset), pnmtopalm generates a nextDepthOffset
field that says there is no following image (and does not add any padding after the
image).

Version 3 Palm Bitmaps actually have a nextBitmapOffset field instead of the
nextDepthOffset. The foregoing applies to whichever is relevant.

The -offset option was new in Netpbm 10.26 (January 2005). Before that, pnmtopalm
always set the nextDepthOffset field to "none."

Before Netpbm 10.27 (March 2005), you cannot use -offset if you create a compressed
raster (because pnmtopalm isn't smart enough to be able to know the size of the
image at the time it writes the header). You also cannot use it with 16 bit color
depth or with the -colormap option, for much the same reason.

-withdummy
This option tells pnmtopalm to put in the stream, after the image, a dummy image
header to introduce subsequent high density images.

This dummy image header is a special sequence specified in Palm Bitmap
specifications. It looks to an older Palm Bitmap interpreter like an invalid image
header, so such an interpreter will stop reading the stream there. But a new Palm
Bitmap interpreter recognizes it for what it is (just something to choke an old
interpreter) and skips over it. Presumably, you will add to the stream after this
high density images which would confuse an older interpreter.

If you specify -withdummy, you must also specify -offset, since it doesn't make any
sense otherwise.

-withdummy was new in Netpbm 10.27 (March 2005).

-colormap
Build a custom colormap and include it in the output file. This is not recommended
by Palm, for efficiency reasons. Otherwise, pnmtopalm uses the default Palm
colormap for color output.

-transparent=colorspec
Marks one particular color as fully transparent.

colorspec is as described for the argument of the pnm_parsecolor() library routine
⟨libnetpbm_image.html#colorname⟩ .

Transparency works only on Palm OS 3.5 and higher.

-scanline_compression
Specifies that the output Palm bitmap will use the Palm scanline compression
scheme. Scanline compression works only in Palm OS 2.0 and higher.

-rle_compression
Specifies that the output Palm bitmap will use the Palm RLE compression scheme.
RLE compression works only with Palm OS 3.5 and higher.

-packbits_compression
Specifies that the output Palm bitmap will use the Palm packbits compression
scheme. Packbits compression works only with Palm OS 4.0 and higher.

This option was new in Netpbm 10.27 (March 2005).

-density=N
This specifies the Palm Bitmap density. The density is a number that is
proportional to the resolution the image should have when displayed. The
proportionality factor is up to whatever is doing the displaying, but it's helpful
to think of these numbers as being pixels per inch. The allowable values are:

• 72

• 108

• 144

• 216

• 288

This option was new in Netpbm 10.27 (March 2005). Earlier Netpbm could not
generate Version 3 Palm Bitmaps, so there was no such thing as density.

NOTES

       Palm Bitmaps may contains multiple renditions of the same bitmap, in different depths.  To
       construct an N-multiple-rendition Palm Bitmap with pnmtopalm, first construct renditions 1
       through N-1 using the -offset option, then construct the Nth  image  without  the  -offset
       option.  Then concatenate the individual renditions together in a single file using cat.

       If  you  will  include  both high density and low density renditions, put the high density
       images last and when you create the last of the low density  images,  use  the  -withdummy
       option.

       If you specify the Palm packbits compression scheme for a 16-bit direct color bitmap, this
       program generates an invalid bitmap.

AUTHORS

       This program was originally written as ppmtoTbmp.c, by Ian Goldberg  and  George  Caswell.
       It  was  completely re-written by Bill Janssen to add color, compression, and transparency
       function.  Copyright 1995-2001 by Ian Goldberg, George Caswell, and Bill Janssen.

DOCUMENT SOURCE

       This manual page was generated by the Netpbm tool 'makeman' from HTML source.  The  master
       documentation is at

              http://netpbm.sourceforge.net/doc/pnmtopalm.html