[css3-writing-modes] Character's intrinsic orientation

Fantasai and I were discussing on the definition of "character's intrinsic orientation". It's described at the text-orientation property[1], after "Example V".

After several investigation, we figured that neither script orientation[2] alone nor Unicode East Asian Width[3] alone is good enough to determine the intrinsic orientation, so we need to modify the logic to use both of them. Current our idea is to revise the logic to the one as below.

IF ScriptOrientation=Translate || (EAW=F|W)
	Always upright
ELIF ScriptOrientation=Rotate # All chars are EAW=N
	Always sideways
ELIF ScriptOrientation=Horizontal # EAW=F|W are already excluded by first IF
	Sideways for ''vertical-right'', upright for ''upright''
ELIF # Script=Common|Inherited|Unknown
	IF EAW=H|N|Na
		Sideways
	ELSE # EAW=A
		...

The "..." part indicates when both script and EAW are ambiguous. Our hope is to rely on font information in that case, and we'll be investigating the appropriate sentences to put in there.

Current our idea is to put sentences like this:

| If the font has information (like vertical alternates or vertical position)
| that indicates intrinsic orientation is upright, it should be honored.

We'll investigate if this is appropriate and get this reviewed by a few people around, but any opinions and/or feedback are greatly appreciated.

[1] http://dev.w3.org/csswg/css3-writing-modes/#text-orientation
[2] http://dev.w3.org/csswg/css3-writing-modes/#script-orientations
[3] http://unicode.org/reports/tr11/


Regards,
Koji

Received on Tuesday, 22 March 2011 12:32:02 UTC