OpenType : Java Glossary

2008-01-15 by Roedy Green ©1996-2008 Canadian Mind Products
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OpenType

A joint project of Microsoft and Adobe to provide cross-platform downloadable fonts. They work on Window, Mac, Sun etc. OpenType fonts usually have the extension *.otf. It is supported in

Sun’s Product Info on Java 1.4+

. Have a look at the Warnock Pro Opticals OpenType font. This is a work of art. Look at the PDFs to get a better feel for what they will look like typeset. I feel awed to look at it, much the way some people tell me they feel awe on seeing Michaelangelo’s David. The aesthetic skill involved is so infinitely greater than ever I could even conceive of achieving.

OpenType is used for video titling in MP4 video. Adobe adds the suffix pro to all its OpenType fonts. OpenType fonts have a 16-bit encoding vector allowing up to 64,535 glyphs. Some fonts even support 32-bit code points. OpenType fonts have hints for more precise rendering at small point sizes.

Some OpenType fonts include four optical size variations: caption, regular, subhead and display. Called Opticals, these shape variations have been optimised for use at specific point sizes. Although the exact intended sizes vary by family, the general size ranges include: caption (6-8 point), regular (9-13 point), subhead (14-24 point) and display (25-72 point).

One character may correspond to several glyphs; the lowercase a, a small cap a and an alternate swash lowercase a are all the same character, but they are three separate glyphs. To the best of my knowledge, Java does not support these variants because Unicode doesn’t.

There are multiple mappings from code point to glyph to handle a variety of encodings such as Symbol, Unicode, ShiftJIS, PRC, Big5, Wansung, Johab and UCS-4. The most important one for Java is Unicode.

Some OpenType fonts have ligatures and caret positioning for ligatures. The OpenType people call this glyph substitution. Java has no support for these.

Opentype fonts provide for both 16-bit Unicode and 32-bit UCS-4 glyph encoding tables. However, I don’t think I have yet seen a character above 0x0ffff rendered on screen on on print yet, other than in the Unicode consortium’s PDF file. We still have not even managed to support very much of the 16-bit part of Unicode yet.

Java Font Support

Font Support Under Java
Font Type	Extension	Java 1.6 Windows	Java 1.6 Linux	Java 1.6 Fedora	Old Java Windows	Notes
OpenType (TrueType internally)	otf					High-end fonts for Windows.
OpenType (PostScript Adobe CCF internally)	otf					High end PostScript fonts. You can detect these by the file signature { 0x4F, 0x54, 0x54, 0x4F } — the string "OTTO", at the head of the file.
TrueType	ttf					Most common font for Windows.
PostScript	pfm/pfb					Older style PS fonts. Supported by PostScript printer hardware. Windows itself supports PS fonts, at least with Adobe Type Manager, but Java ignores them.
Bitmap	fon					Used primarily for small font sizes. Come only a small set of point sizes.
Vector outline	fon					These are obsolete. Used by Windows without Java.
8-bit fonts	any					Java needs 16-bit fonts. It won’t use 8-bit fonts directly. Old or specialty 8-bit fonts can be used by stitching them together with a Unicode mapping, a daunting task.

AWT will only support the five basic logical fonts, unless you paint on a Canvas, however oddly under Fedora and AWT you can use up to 82 of your installed fonts. If you try to use more, you get an ArrayIndexOutOfBoundsException. The above information may be incorrect or may become incorrect at any time. Feel free to try any fonts with Java on any platform. The worst that could happen is they won’t work.

Adobe OpenType introduction
Font
Luc Devroye’s OpenType links
Microsoft’s OpenType file layout spec
otfinfo: utility to display font meta-information
PostScript
TrueType
Webfont

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