Adding OpenType features: Long GSUB Strings

[William]

@Bhikkhu Pesala

A warning: Experimental stuff like this is fine to test FontCreator and see what it can do, but don’t add features just for the sake of it. Give some thought to how practical it is, and how well your font will work if someone is using it in an application that doesn’t support OpenType.

In a post in this thread, timestamped at 25 Apr 2013 09:13 I wrote as follows.

@William

As it happens I have been thinking about the way to try to get my ideas about localizable sentences implemented and I was thinking yesterday about whether a GSUB in a liga table would be able to handle a sequence of seven characters and substitute a glyph.

Later in the same post I wrote as follows.

@William

I know that this might be an extreme use of a GSUB in a liga table, but if it is possible to do this it would be helpful for my research.

I refer to the following post in another thread.

Localizable Sentences Experiment font support

I have submitted a proposal to the Unicode Technical Committee with the following title. A proposal for encoding twelve localizable sentence markup bubble characters, together with a request for action to set up an encoding infrastructure for the encoding in a separate standardization document of complete localizable sentence markup bubbles using those twelve characters The document is available from a link labelled L2/13-079 on the following web page. http://www.unicode.org/L2/L-curdoc.htm T…

Now, as it happens, I have been informed that encoding has been declined and I have been advised to use markup.

I do not want to use xml as I think, though I am not totally sure, that that would require the whole document to become an xml document.

I want a markup bubble within a plain text document.

I feel that using special characters would be the best, yet that has been declined, so I am now thinking about using a markup format of two colons followed by five (or more if needed) digits followed by a colon and a semicolon.

That way, the coding can be displayed in plain text.

I am now thinking of having a liga table for the markup bubble brackets and dlig for whole glyphs, which would require a total of nine characters to be glyph substituted, maybe more if the system expands, though nine will be enough for now.

I have not yet tested this out in a font, but I note that dlig is before liga in the default template.

Also, if the system is ever implemented, the markup bubbles would not usually be displayed as each markup bubble would become replaced at the receiving computer by a sentence localized into the local language.

I would prefer standardization of the list of localizable sentences to be done by a standards body, though that might not be possible.

William Overington

24 May 2013