Hexafonter

A command-line tool that will convert a PNG file with a fixed-width pixel font for small LCD displays, like this:

to a C file with a sideways preview and a character code legend, like this:

See sample-output.c for the full thing -- but note that you need a relatively modern monospace font for this to look good.

Installation

You need Python 3.6+ and the png module.

In a Python virtual environent, you can install the tool as:

python -m pip install hexafonter

Usage

To convert a PNG to a C font file:

python -m hexafonter font.png > output-font.c

By default, the tool expects characters to be 8 pixels tall 6 pixels wide. The height is hard-coded, but you can change the width by adding a number:

python -m hexafonter arcade-font.png 8 > output-font.c

Several options let you select a preamble, which should contain the C variable declaration (up to =), and any #include or #define directives or other code you need before it. The default preamble is:

const unsigned char font[] =

You can customize it with these options:

• -p preamble-file: Load a preamble from the given file
• -p -: Use no preamble (useful if you prepend it some other way)
• -P ...: Use the ... directly
• -progmem: Use a preamble for Arduino-style PROGMEM

Other options:

• -o outfile.c: Output to the given file, rather than stdout (i.e. don't combine this with the > outfile part shown above)
• -r: Reverse mode -- convert a C file to a PNG instead. (May not work with files generated by other tools. Details not present in the C file will be lost. On the other hand, the resulting PNG will be relatively small.)
• -h: Get help

Details of operation

The tool looks at the red channel of each pixel and does a very basic treshold operation. That means:

• Don't use (semi-)transparent images. (The tool does not “see” what you see in the transparent regions.)
• Dark colors, especially green/cyan/blue, are treated as black (on).
• Light colors, especially red/yellow/magenta, and all are treated as white (off).

The preview in the C file uses Unicode BLOCK SEXTANT characters.

License

The tool is provided under the MIT license. May it serve you well.