For converting back and forth between the image and source you can use xxd. In a Windows environment you can use this command in the Linux Subsystem installing one of the versions available (i.e. Ubuntu).

xxd -i input_image.bmp output.hpp

xxd -r -p input.hpp output_image.bmp

There is also a python helper in firmware/tools/bmp_tools

The special file firmware/application/bitmap.hpp contains all firmware icons.
This file should not be edited directly! Instead, new icons should be copied in firmware/graphics and then run python [firmware/tools/bitmap_tools/pp_png2hpp.py](https://github.com/portapack-mayhem/mayhem-firmware/blob/next/firmware/tools/bitmap_tools/pp_png2hpp.py) <DIRECTORY> bitmap.hpp to create bitmap.hpp.

For operating that Python3 script, Pillow library is required: pip install pillow

The make_bitmap.py is the traditional helper, well tested. The folder with the icons is given as argument and generates the bitmap.hpp. This file needs to be copied to mayhem-firmware/firmware/application/. Starting from the `tools/ folder, the command is:

python3 bitmap_tools/make_bitmap.py ../graphics/ && mv bitmap.hpp ../application/bitmap.hpp

The icon size needs to be a multiple of 8. The generated icon is black/white.

The bitmap_arr_reverse_decode.py takes an array from the bitmap.hpp and convert it back to a png.

The pp_png2hpp.py is based on the previous scripts, as all in one solution.

With the --hpp bitmap.hpp file and the --graphics /folder_to/png_icons/ arguments, this script will generate a bitmap.hpp.
Add the --reverse argument to generate png icons from a given bitmap.hpp.

The reverse function got a parser, for automatic get the filename and size of the image.

From the tools/ folder:

$ ./bitmap_tools/pp_png2hpp.py ../application/bitmap.hpp ../graphics
Converting from png to hpp
From path ../graphics/ to file ../application/bitmap.hpp
Find your bitmap.hpp at ../application/bitmap.hpp

To reverse the icons from the .hpp to png icons use the parameter --reverse. Default is only the mayhem logo, named titlebar_image:

$ ./bitmap_tools/pp_png2hpp.py ../application/bitmap.hpp /home/lupus/work/hackrf/tmp/ --reverse 
Reverse: Converting from hpp to png
Converting icon titlebar_image

Add the parameter --icon <icon name> to convert another icon or all to convert all available icons at once:

$ ./bitmap_tools/pp_png2hpp.py ../application/bitmap.hpp /home/lupus/work/hackrf/tmp/ --reverse --icon all

Note: It is not a recovery, the icons will be new generated. The new icons are black/white, even if the original icons where transparent.

The current icons were designed on Piskelapp. To create or update icons, the current sources (16x16 or 8x8) can be used.