Open Relay Tools

Miscellaneous tools for building and modifying fonts.

Modifying FontForge Source Files

The tool sfdpatch.py modifies FontForge .sfd files. For example:

Sort glyphs by code point:

python tools/sfdpatch.py input.sfd -s > output.sfd

Remove characters:

python tools/sfdpatch.py input.sfd -r 'uniF000 uniF001 uniF002 uF0000' > output.sfd

Remove all characters not the width of a space:

python tools/sfdpatch.py input.sfd -m > output.sfd

Modifying TrueType Font Files

The tool ttfhack.py modifies TrueType .ttf files. For example:

Changing ascent and descent:

python tools/ttfhack.py if=input.ttf winAscent=800 winDescent=200 of=output.ttf

Changing xHeight and capHeight:

python tools/ttfhack.py if=input.ttf xHeight=500 capHeight=700 of=output.ttf

Changing the top and bottom of the bounding box:

python tools/ttfhack.py if=input.ttf yMax=1308 yMin=-544 of=output.ttf

Unicode Character Data & Private Use Area Assignments

The tool pullucd.py will download Unicode Character Database files from unicode.org, either the latest version:

python tools/pullucd.py --latest -d myunicodedata

Or a specific version:

python tools/pullucd.py -v 16.0.0 -d unicodedata16

The tools blocks.py and unicodedata.py create equivalent data files for characters in the Private Use Area. For example:

python tools/blocks.py --tengwar --cirth > Blocks.txt
python tools/unicodedata.py --tengwar --cirth > UnicodeData.txt

These tools look in the directory unicodedata for data files matching flags like --tengwar or --cirth in the above example. You can also specify data files outside of this directory:

python tools/blocks.py --tengwar --cirth ./mydata/applebanana.txt > Blocks.txt
python tools/unicodedata.py --tengwar --cirth ./mydata/applebanana.txt > UnicodeData.txt

The tool puaabook.py can use these files to create HTML documentation for the Private Use Area of your font:

python tools/puaabook.py -D Blocks.txt UnicodeData.txt -I myfont.ttf -O pua.html

The tool pypuaa.py can use these files to create a PUAA table in your font containing this data:

python tools/pypuaa.py -D Blocks.txt UnicodeData.txt -I myfont.ttf

See the PUAA table in the Bits'n'Picas wiki for information about this table. It's currently only used by Bits'n'Picas and PushChar.

Creating New Private Use Area Data Files

Say you have a set of characters for your conscript Applebanana at FAB00..FAB3F and you want to create a private use area data file for it. Your file will be named ud0fab00-applebanana.txt and contain:

@flag --applebanana
@file Blocks.txt
FAB00..FAB3F; Applebanana
@file UnicodeData.txt
FAB00;APPLEBANANA CAPITAL LETTER APPLE;Lu;0;L;;;;;N;;;;FAB20;
FAB01;APPLEBANANA CAPITAL LETTER BANANA;Lu;0;L;;;;;N;;;;FAB21;
...
FAB20;APPLEBANANA SMALL LETTER APPLE;Ll;0;L;;;;;N;;;FAB00;;FAB00
FAB21;APPLEBANANA SMALL LETTER BANANA;Ll;0;L;;;;;N;;;FAB01;;FAB01
...

Please reference UAX #44 Unicode Character Database for the syntax of character property files.

You may issue pull requests to this repository to add your own private use area assignments, however:

• Please limit the number of changed files in a pull request to two or three files at most. The more files there are the harder it is to review the pull request.
• Inclusion in this repository does not indicate endorsement or inclusion in any registry maintained elsewhere. This is not the place to propose new scripts or characters for CSUR, UCSUR, MUFI, SMuFL, or any other private use area agreement. If that is your goal, please contact the maintainers of the respective registry. For UCSUR, please look for the About link at the bottom of the page. :)
• Do not submit new data files without any character data. If you don't know how you're going to use your block of code points, it's not ready to be in a public repository. Do not speculate about future usage of code space; just because there is a data file for Tengwar Presentation Forms at FE000..FE07F does not mean there will ever be a "Cirth Presentation Forms" at FE080..FE0FF.
• Do not include a @substring line in any new data files. This directive and the syntax for blocks.py and unicodedata.py which uses it is deprecated.