Re: [css-writing-modes] 'writing-mode' and deprecated SVG values

On 28/7/15 08:57, Cameron McCormack wrote:

> Dirk Schulze:

>> For backward compatibility (WebKit and Blink support the old property
>> values for SVG text) I would like to suggest to make them deprecated
>> but mandatory. All values must be mapped as suggested by the spec
>> currently.
>> For tool creators and libraries it is just not possible to address
>> browsers with full CSS3 Writing Mode support, browsers based on
>> current WebKit and Blink as well as older (often proprietary) SVG
>> viewers at the same time.
> That’s really only the case if you don’t want to use CSS to do the
> fallback thing.
> I don’t really want to add these value aliases if it can be helped.  Is
> it really true that there is content on the web that needs them?  (If
> there is, then it’s pretty simple for us to add the aliases.)

There is such content, though I don't know whether there's enough of it 
to justify doing this. An example:

The block of text below the second photograph there is intended to be 
rendered vertically. However, it doesn't work in Firefox (even the 
latest developer/nightly builds, where writing-mode support is enabled).

The relevant CSS excerpt from that site reads:

     -webkit-writing-mode: vertical-rl;
     -moz-writing-mode: vertical-rl;
     -ms-writing-mode: tb-rl;
     -o-writing-mode: vertical-rl;
     writing-mode: tb-rl;

This provides a '-moz-'prefixed value with the appropriate value, but 
this is ignored as Gecko never implemented writing-mode with a prefix; 
and it provides an unprefixed rule using the legacy SVG value tb-rl, 
which Gecko doesn't support. So it simply doesn't work; the content 
remains horizontal.

Aliasing tb-rl to vertical-rl (etc) would make this render as intended 
in Gecko. (Alternatively, of course, we can reach out to the site and 
ask them to fix the CSS. I've been in touch with webcompat and MozJapan 
people about it, but don't know if any progress is happening...)

I have no idea how much content may be out there with CSS like this, but 
I'm concerned that IE11 appears to support *unprefixed* 'writing-mode' 
with the *legacy* values such as 'tb-rl', and does *not* support the 
preferred CSS3 Writing Modes values. This will tend to mislead IE-using 
authors into continuing to write things like 'writing-mode: tb-rl'. :(


Received on Tuesday, 28 July 2015 08:53:32 UTC