How to convert a bitmap font (.FON) into a truetype font (.TTF)?

Use FontForge + Autotrace then make some corrections manually.

First integrate Autotrace in Fontforge, see Autotracing bitmaps in FontForge. Here is how I have done it, as I wasn’t able to use the win32 version of FontForge:

  1. Download, unzip and start Portable Ubuntu Tres. It’s a special linux version that works under Windows!
  2. Choose System->Administration->Add/Remove Applications, search for FontForge and install it (administrator password is 123456). I got FontForge version 20090622 installated.
  3. Download autotrace-0.31.1.tar.gz from and copy it in your home directory in Portable Ubuntu.
  4. In Portable Ubuntu choose Applications->Accessories->Terminal to compile and install autotrace:

    sudo bash  (password is 123456)
    gunzip autotrace-0.31.1.tar.gz
    tar xf autotrace-0.31.1.tar
    cd autotrace-0.31.1
    make install

Then convert your font:

  1. Start FontForge in Portable Ubuntu and open the .FON font.
  2. Save your font as a .BDF font (Loading a .FON file as background didn’t work for me so I had to convert the font first): File->Generate Fonts and choose BDF as format.
  3. Create a new font and import the BDF Font as background font: File->Import and don’t forget select “As Background”.
  4. Select all characters and start an autotrace while holding the shift key so that you can enter parameters for autotrace. I used following parameters, which improved the recognition of the outline of the pixels but I didn’t found the perfect parameters:

    -corner-surround=1 -line-threshold=10
  5. Correct the chars manually using mostly the function “Add a curve point”.
    Activating View->Show->Almost Horizontal/Vertical Lines makes the work much easier.
  6. Generate a truetype font: File->Generate Fonts and choose truetype as format.

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