README.md

FONS
====
A tool to make fonts out of bitmap images.

Tools needed
------------
- Gimp
- Gimp G'MIC plugin
- Autotrace
- Fontforge with Autotrace



Process
-------

### Image

#### Get a bitmap image of characters (crop unnecessary white parts for a faster process, you can use Gimp's automatic crop for that).

![](http://osp.kitchen/api/osp.tools.fons/raw/input/scan_bitmap.jpg)
:    A scan in bitmap

![](http://osp.kitchen/api/osp.tools.fons/raw/input/scan_gray_1200dpi.jpg)
:    A scan in gray levels

![](http://osp.kitchen/api/osp.tools.fons/raw/input/rasterized_ospDIN.png)
:    A rasterized font





#### Levels (have a white background, black characters but still shades of gray)

![](http://osp.kitchen/api/osp.tools.fons/raw/documentation/01-bitmap_levels.png)



#### Small boost 

Scale up the image to something like 254% with the "Sinc (Lanczos 3)" algorithm. We choose on purpose a non-round number of scaling to break the bitmap patterns.

![](http://osp.kitchen/api/osp.tools.fons/raw/documentation/02-scale-254percent.png)



#### Sharpen with "Unsharp mask"

Put the amount to the maximum and then search for the point where you don't see 

![bad](http://osp.kitchen/api/osp.tools.fons/raw/documentation/03-sharpen-too_few.png)
:    Radius too small

![ok](http://osp.kitchen/api/osp.tools.fons/raw/documentation/03-sharpen-ok.png)

![bad](http://osp.kitchen/api/osp.tools.fons/raw/documentation/03-sharpen-too_much.png)



#### Big boost

Scale up to 403% (check on notebook or with PierreH if it's enough)

![](http://osp.kitchen/api/osp.tools.fons/raw/documentation/04-big_boost.png)



#### Threshold


![bad](http://osp.kitchen/api/osp.tools.fons/raw/documentation/05-threshold-bad.png)


![ok](http://osp.kitchen/api/osp.tools.fons/raw/documentation/05-threshold-ok.png)


Save as a .bmp file.


### GlyphTracer

- Launch GlyphTracer and feed in the .bmp image (otherwise it will complain).
- For each given glyph, click on the letter you want to use.
- Change the characters subset in the bottom left dropdown menu to select more glyphs.



IMPORTANT: If you zoom out to select the letters, don't forget to go back to zoom 1 before generating the font file. Don't close GlyphTracer before checking the .sfd file, then you can export again if you forgot to zoom back in.


### Merging fonts

In case you want to complete an existing font, you can use the script `mergeFonts.py`.

    python mergeFonts.py fonte1.ufo fonte2.ufo ...  fonte17.ufo fonte-out.ufo


### Metrics and kernings

A big part of type design is about managing the white space around the letters (metrics) and exceptions for specific couples of letters (kernings).

- For the metrics, we make an auto-spacing while generating the .sfd file with GlyphTracer.
- For the kernings, you can try the tool (Kernagic)[https://github.com/hodefoting/kernagic].

But if you want to get back metric and kerning data from an existing font, you can use the script `mergeSpacing.py`. It can be any font format than `.otf`.

   python mergeSpacing.py font.otf original-font.otf spaced-font.otf



Troubleshooting
---------------

### My image is too big to manipulate it.
Split it into several images and generate several .sfd files. Then you can merge the fonts with the script `mergeFonts.py`.


### I have empty and very small width when I open a glyph in Fontforge.
You probably generated the .sfd with a zoom level different than 1.


### I see several letters in ony glyph.
You probably generated the .sfd with a zoom level different than 1.