From: John Hudson (john@tiro.ca)
Date: Fri Aug 24 2007 - 17:05:27 CDT
When we're making OT fonts for complex scripts in which control characters such as
ZWJ/ZWNJ or directionality control marks are expected to be encountered in text, we do
include visible glyphs for these characters, and our expectation is that the application
will control whether these display or not depending on user-settings. Ideally, these
glyphs are zero-width but with visible indicators above the text, so that they are easily
visible. There are a few visual conventions for the display of common control characters,
mostly intuitive.
Some apps have problems with these visible glyphs, because they have not figured out that
they need to suppress display unless the user wants them for editing purposes. Usually, if
this is pointed out to them they understand how the fonts are designed to work, and there
seem to be enough such fonts on the market to drive app developers to work according to
this model.
This is not to say that it is the best possible model. I can imagine a model in which
control character glyphs would always be zero-width blank glyphs, and in which editing
mode in applications would provide their own visualisation of control characters.
John Hudson
-- Tiro Typeworks www.tiro.com Gulf Islands, BC tiro@tiro.com Do not begin to paddle unless you intend always to paddle. - St Jean de BrΓ©beuf, instructions for missionaries, 1637
This archive was generated by hypermail 2.1.5 : Fri Aug 24 2007 - 17:06:55 CDT