RE: bidi tests assume undefined letter-spacing behavior

On Friday, January 07, 2011 3:50 PM fantasai wrote:
> On 01/07/2011 03:20 PM, Arron Eicholz wrote:
> > On Sunday, December 05, 2010 1:43 AM fantasai wrote:
> >> On 10/13/2010 09:48 PM, L. David Baron wrote:
> >>> The following tests:
> >>> http://test.csswg.org/suites/css2.1/20101001/xhtml1/bidi-005.xht
> >>> http://test.csswg.org/suites/css2.1/20101001/xhtml1/bidi-006.xht
> >>> http://test.csswg.org/suites/css2.1/20101001/xhtml1/bidi-007.xht
> >>> http://test.csswg.org/suites/css2.1/20101001/xhtml1/bidi-008.xht
> >>> http://test.csswg.org/suites/css2.1/20101001/xhtml1/bidi-009.xht
> >>> http://test.csswg.org/suites/css2.1/20101001/xhtml1/bidi-010.xht
> >>> http://test.csswg.org/suites/css2.1/20101001/html4/bidi-005.htm
> >>> http://test.csswg.org/suites/css2.1/20101001/html4/bidi-006.htm
> >>> http://test.csswg.org/suites/css2.1/20101001/html4/bidi-007.htm
> >>> http://test.csswg.org/suites/css2.1/20101001/html4/bidi-008.htm
> >>> http://test.csswg.org/suites/css2.1/20101001/html4/bidi-009.htm
> >>> http://test.csswg.org/suites/css2.1/20101001/html4/bidi-010.htm
> >>>
> >>> assume letter-spacing behavior that is, as far as I can tell,
> >>> undefined in CSS 2.1.
> >>>
> >>> While I agree Gecko's current behavior is suboptimal (and probably
> >>> best fixed by implementing what is required by css3-text (in bug
> >>> 299943)), I don't think these tests are valid as tests for CSS 2.1.
> >>
> >> Which element generates letter-spacing at an element boundary is not
> >> defined in CSS2.1. But the letter-spacing here is consistent
> >> throughout the paragraph. Gecko is failing here because the
> >> inter-character spacing is inconsistent.
> >>
> >> You might be right that the test is dependent on undefined behavior
> >> at element boundaries, but in that case I'd split the test into two
> >> halves: one that checks the location of element borders, and another
> >> that tests interaction with letter-spacing.
> >> (I'm having trouble right now coming up with a letter-spacing
> >> behavior that would require this split, though; i.e that would pass
> >> with the split, but fail with the current combination.
> >> But if you think I should split the tests, then let me know and I'll
> >> split them.)
> >
> > I think the cases should be split since we do not define the placement
> > of the letter spacing space.
> 
> We do, however, require that the space between the letters must be
> consistent: there is no allowance for varying inter-letter spacing at bidi
> boundaries. So do we have an implementation that has consistent space
> between the letters *and* fails the test? Because if not, there's no practical
> reason for me to split them.

Actually I see no place in the CSS spec where we say that letter spacing should be consistent. Granted I think it should be consistent could mean you always place it after the character in the text runs current direction. Which means the test needs to be altered.

> 
> > For CSS3 we should define the letter spacing space to be placed after
> > the character in the current text run direction. This would match most
> > implementations. However, for CSS 2.1 this should be just undefined
> > and we can just correct the tests.
> 
> CSS3 already has a better definition.
> 

Great that is what I was hoping for in CSS3.

--
Thanks,
Arron Eicholz

Received on Saturday, 8 January 2011 00:24:37 UTC