[liblouis-liblouisxml] Expanding the typeforrm parameter
- From: "John J. Boyer" <john.boyer@xxxxxxxxxxxxxxxxx>
- To: liblouis-liblouisxml@xxxxxxxxxxxxx
- Date: Mon, 14 Oct 2013 06:09:17 -0500
Let me know if you have comments on the folowing.
At present the typeform parameter can handle only four kinds of
emphasis, bold, italic, underline and computer Braille. Although this
parameter is a character array the high-order bits are used for the
ascii numeric code, -x30. This is because at the beginning loblouis
functions were called from Visual Basic.
However, four types of emphasis are not enough to handle the Braille
indicators required by modern textbooks, where it may be necessary to
indicate colored type, script, etc.
Therefore, I am proposing to use all eight bits of the typeforrm
parameter. To preserve backward compatibility an additional bit in the
mode parameter will be defined, extTypoeform . Since the spacing
parameter is used only by ViewPlus and they may stop using it, I propose
to make it an extension of the typeform parameter. This will provide 12
additional ways to indicate things in the text. It will also be
controlled by the extTypeform bit.
The present system of defining opcodes for things like beginning of
phrase, end of phrase, etc for each type of emphasis is unworkable for
an extended typeform parameter because it would result in a huge number
of opcodes.
The present algorithm for handling Braille indicators cannot be expanded
for the same reason. Therefore, the correct-context-multipass feature
will be extended with a scripting language. The base of this language
already exists.
John
--
John J. Boyer; President, Chief Software Developer
Abilitiessoft, Inc.
http://www.abilitiessoft.com
Madison, Wisconsin USA
Developing software for people with disabilities
For a description of the software, to download it and links to
project pages go to http://www.abilitiessoft.com
Other related posts:
