====== Custom fonts for Ucglib ======

This is how I built custom fonts for [[https://github.com/olikraus/ucglib | Ucglib]]/[[https://github.com/olikraus/Ucglib_Arduino | Ucglib_Arduino]] on Linux.

Ucglib uses [[https://en.wikipedia.org/wiki/Glyph_Bitmap_Distribution_Format | BDF]] fonts as a source. The basic process to convert a typical font file for use in Ucglib is:
  * Convert an OTF or TTF font to BDF format using ''[[ http://sofia.nmsu.edu/~mleisher/Software/otf2bdf/ | otf2bdf ]]'', ''[[http://sofia.nmsu.edu/~mleisher/Software/gbdfed/ | gbdfed]]'', or ''[[https://fontforge.github.io/en-US/ | fontforge]]''. //Check font licenses!//
  * Use ''bdconf'' to convert the BDF format to C.
  * Add the new code to the appropriate Ucglib file.

Details are provided below.

===== Requirements =====

==== Getting otf2bdf and fontforge ====

''%%otf2bdf%%'', ''%%gbdfed%%'' and ''%%fontforge%%'' are available in many Linux distributions.

==== Building bdfconv ====

You will probably have to build ''%%bdfconv%%'' yourself. Download the [[https://github.com/olikraus/ucglib|Ucglib repository]], move into ''%%tools/font/bdfconv%%'' and

<code shell>
$ make
</code>

This will build a ''%%bdfconv%%'' executable. Put that executable or a symbolic link to it into your ''bin'' directory. 

===== The process =====

==== Convert OTF or TTF to BDF ====

Using ''otf2bdf'':

<code>
$ otf2bdf -v -n -r 72 -p 71 -l '32 48_57 65_90' -c M -o filename.bdf filename.otf
</code>

''%%gbdfed%%'' also can import and convert fonts, but the monospace/proportional setting seems to be wonky. ''%%fontforge%%'' may be another option.

View the result using ''%%gbdfed%%'' or ''%%fontforge%%''.

Once the font is in BDF format, you can use ''%%fontforge%%'' to edit it, which might include removing unused characters or tweaking bitmaps.

==== Convert the BDF file to C using bdfconv ====

<code>
$ bdfconv -v -b 2 -f 0 -n fontname -d image.tga -o filename.c filename.bdf 
</code>

Note: There seems to be an upper limit to the size of the font. FIXME What is it?


==== Add new code to Ucglib ====

  - Paste the content of the new C file to ''%%src/clib/ucg_pixel_font_data.c%%'' --- making sure to remove the redundant<code c>#include "ucg.h"</code>
  - Add an ''%%extern%%'' entry for the above variable to ''%%src/clib/ucg.h%%''