Medley Web Font Metrics Extractor

This is software that generates font metrics files suitable for the Medley HTMLSTREAM device-independent graphics implementation.

Character Encoding

Medley uses Xerox Character Code Standard (XCCS) 2.0+ to represent characters. XCCS is one of the predecessors of, and a major influence on, the Unicode standard. XCCS can represent up to 65,535 characters and organizes them in 256-character sets.

Unicode is able to represent many more characters than XCCS. The majority of the character glyphs defined in XCCS are also present in Unicode, though there are exceptions.

Supported Fonts

We opted not to create our own fonts, but rather to select open source fonts created by others.

We've chosen fonts capable of representing as large a set of XCCS characters as possible. Since there are no XCCS-native fonts suitable for use on the Web, in practice, this means we're choosing fonts that cover as much of the Unicode character space as possible. We also desire that our fonts include multiple faces, and consider serif, sans serif, monospaced, and display as the basic set.

Based on these criteria, we focussed on Google's font collection. We had a brief dalliance with Roboto before realizing its shortcomings (principally that it covers a small portion of the Unicode and XCCS code spaces than we'd like), we settled on Noto.

We've defined 4 Medley font families based on Noto:

1. NONO-SANS
2. NOTO-SANS-MONO
3. NOTO-SANS-DISPLAY
4. NOTO-SERIF

Each family is available in these styles:

1. Plain
2. Italic
3. Bold
4. Bold Italic

Each face+style is available in these point sizes: 8, 10, 12, 14, 16, 18, 20, 24, 32, 40, 92

Prerequisites

• An Internet connection. The tool downloads its fonts as webfonts when it starts up.
• A Java development kit (JDK), version 21.

Generating font metrics files

Class Main provides the font metrics generator (and other tools too).

To run it, create a destination directory for the metrics files (here /font/destination/directory):

$ mkdir /font/destination/directory

You don't need to download any font files: the software accesses its fonts as webfonts over the Internet.

Simply run the font metrics generator:

$ java -cp WebFontMetrics.main org.interlisp.Main -d /font/destination/directory

The process will generate a large number of files, one for each combination of family X style X size X XCCS character sets, plus one table of contents for each combination of family X style X size.

Viewing font coverage

To see what portion of the XCCS code space a given set of font components (a "font stack") covers, tun

$ java -cp WebFontMetrics.main org.interlisp.FontCoverage