man > pamtowinicon(1)

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⚡ TLDR: pamtowinicon (tldr-pages)

Convert a PAM image to a Windows ICO file.

Convert a PAM image file to an ICO file
pamtowinicon {{path/to/input_file.pam}} > {{path/to/output.ico}}
Encode images with resolutions smaller than `t` in the BMP format and all other images in the PNG format
pamtowinicon {{-pn|-pngthreshold}} {{t}} {{path/to/input_file.pam}} > {{path/to/output.ico}}
Make all pixels outside the non-opaque area black
pamtowinicon {{-t|-truetransparent}} {{path/to/input_file.pam}} > {{path/to/output.ico}}

Pamtowinicon User Manual(1) General Commands Manual Pamtowinicon User Manual(1)

NAME
pamtowinicon - convert Netpbm PAM images to a Microsoft Windows icon file

SYNOPSIS
pamtowinicon [-pngthreshold=threshold] [-truetransparent] [-verbose] [pam_file]

All options can be abbreviated to their shortest unique prefix. You may use two hyphens in‐
stead of one to designate an option. You may use either white space or equals signs between
an option name and its value.

DESCRIPTION
This program is part of Netpbm(1).

pamtowinicon reads an RGB_ALPHA Netpbm PAM file and converts it to a Microsoft Windows icon
file.

The output goes to Standard Output.

The input is a multi-image PAM file; each image becomes an icon in the output file. If you
have input images in multiple files, you can simply combine them with cat and pass the result
to pamtowinicon.

OPTIONS
In addition to the options common to all programs based on libnetpbm (most notably -quiet,
see ]8;;index.html#commonoptions\Common Options]8;;\ ), pamtowinicon recognizes the following command line options:

-pngthreshold=threshold
pamtowinicon encodes images with resolutions above or equal threshold by threshold as
PNG by running pnmtopng(1). Other images it encodes using the more traditional BMP
format.

When the program uses PNG encoding for a 5-channel PAM with separate AND mask (see be‐
low), it discards the AND mask. Because PNG has always had the ability to specify
transparency, the Windows icon format does not provide for a separate and mask when
the icon is encoded in PNG.

The default value for threshold is 128.

-truetransparent
Make all pixels outside the opaque area black, avoiding inversion and other effects on
the background of the image (see Windows Icons(1)).

-verbose
Print more messages

IMAGES
pamtowinicon reads a (multi-image) Netpbm PAM file as input and outputs an single Windows
icon file containing those images.

The images in the icon file are in the same order as in the PAM input.

PAM Input
pamtowinicon interprets the PAM images as follows, based on the number of channels.

────────────────────────────────────────────────────────────────────
channels image
1 fully opaque grayscale image
2 grayscale image with transparency channel
3 fully opaque color image
4 color image with transparency channel
5 color image with transparency channel and additional AND
mask

The tuple types of the PAMs are irrelevant.

AND Mask
The so-called "AND mask" is a special feature of Microsoft Windows icons. It is required for
all BMP encoded images. At the first sight, the AND mask is a 1-bit transparency channel,
but it is also used for e.g. shading the icon while dragging. See Windows Icons(1) for de‐
tails.

If there is no explicit AND mask, but transparency data in the input image, pamtowinicon sets
the AND mask to opaque where the sample in the transparency channel is below maxval, and to
transparent elsewhere.

If no transparency data is present in the input image, pamtowinicon assumes the whole image
to be fully opaque.

BMP Output
When BMP encoding an image, pamtowinicon tries to use the most compact BI_RGB format allowed
for icon images with a color depth of eight bits per channel.

pamtowinicon generates neither 16-bit BI_RGB nor BI_BITFIELDS BMP encoded images, even if the
maxval of the input PAM is not 255.