palmtopnm

Convert a Palm bitmap to a PNM image

$ palmtopnm [path/to/file.palm] > [path/to/file.pnm]

$ palmtopnm [[-verb|-verbose]] [path/to/file.palm] > [path/to/file.pnm]

$ palmtopnm [[-r|-rendition]] [n] [path/to/file.palm] > [path/to/file.pnm]

$ palmtopnm [[-s|-showhist]] [path/to/file.palm] > [path/to/file.pnm]

$ palmtopnm [[-t|-transparent]] [path/to/file.palm]

palmtopnm [-index N] [-forcecolor] [-verbose] [palmfile]

-index N
    Selects the Nth image from the input file. Some Palm database files can contain multiple bitmap images. This option specifies which one to convert. If omitted, the first image (index 1) is typically selected.

-forcecolor
    Forces the output to be in PPM (color) format, even if the input Palm image appears to be grayscale or monochrome. By default, palmtopnm tries to determine the most appropriate PNM format (PBM, PGM, or PPM) based on the image content.

-verbose
    Prints verbose information about the conversion process to standard error. This can be useful for debugging or understanding how the command interprets the input file.

palmfile
    The path to the Palm Pilot image database file (.pdb or .prc) to be converted. If this parameter is omitted, palmtopnm reads its input from standard input.

palmtopnm is a command-line utility that converts bitmap images found within Palm Pilot database files (commonly with .pdb or .prc extensions) into the Portable Anymap (PNM) format. PNM is a collective term for PBM (Portable Bitmap), PGM (Portable Graymap), and PPM (Portable Pixmap). This tool is part of the extensive Netpbm graphics toolkit, which provides a rich set of utilities for manipulating graphic images.

It reads the Palm image data, which can contain multiple images, and outputs the converted image to standard output, suitable for piping to other Netpbm tools or saving to a file. The command automatically determines the best PNM subformat (PBM, PGM, or PPM) based on the color depth of the input Palm image, unless overridden by options.

palmtopnm relies on the internal structure of Palm Pilot bitmap records, which can vary across different Palm OS versions or applications. It may not correctly parse all historical or future variations of Palm image formats.

The command always writes the converted PNM image to standard output. To save it to a file, you must redirect the output (e.g., palmtopnm input.pdb > output.pnm).

The quality of the conversion depends on the accuracy of the Palm image format specification implemented by the tool.

When no palmfile argument is provided, palmtopnm reads the Palm Pilot image data from standard input. This allows it to be used in pipelines, e.g., cat image.pdb | palmtopnm > output.pnm. The output PNM image is always written to standard output, making it highly compatible with other command-line tools.

As a component of the Netpbm suite, palmtopnm is designed to integrate seamlessly with other Netpbm utilities. The PNM output can be easily piped to other tools for further processing, such as scaling (pnmscale), cropping (pnmcut), converting to other widely used formats (pnmtojpeg, pnmtopng, pnmtogif), or applying various image effects.

palmtopnm is part of the Netpbm project, which evolved from the PBMplus package developed by Jef Poskanzer. The Netpbm toolkit has been a staple in Unix-like environments for image manipulation since the early 1990s, providing a modular and extensible set of tools for converting and transforming various image formats, including this specific utility for Palm Pilot images. Its development reflects the need for cross-platform image conversion tools in the era of early personal digital assistants (PDAs).

pnm(5), pbm(5), pgm(5), ppm(5), anytopnm(1), netpbm(1)