Create an ARGB struct for C header from a PNG

Question

I need to update a logo bitmap to an updated logo. The existing code uses a C header which is loaded via XChangeProperty.

I have looked into imagemagick and the Gimp in order to convert the updated png I have into a suitable header. Gimp even said 'export a C header' (or something like it) but the result did not resemble the existing format.

How do I go (preferably on the command-line) from a png to a suitable header file?

Edit: Expanding the question a little, the (now out of date) logo I would like to replace is in this file and gets used here.

Answer 1

Using ImageMagick, based on rlogo_icon.h.

#!/bin/sh
echo 'unsigned long rlogo_icon[] = {'
identify -format '%w, %h,' $1
convert $1 -color-matrix '0 0 1 0, 0 1 0 0, 1 0 0 0, 0 0 0 1' RGBA:- | hexdump -v -e '1/4 "0x%08x,\n"'
echo '};'

Usage:

./script.sh rlogo_icon.png > rlogo_icon.h

I'm not sure this -color-matrix is always correct. I placed bytes in the order of BGRA because my computer is little endian.