Re: [css-writing-modes] Behavior of <iframe> in vertical writing mode

On 7/8/15 03:46, fantasai wrote:
> On 08/06/2015 05:45 AM, Jonathan Kew wrote:
>> I'm wondering how <iframe>s should be handled when writing-mode is
>> vertical.
>>
>> First, what should the default size be, in the absence of any other
>> constraints? In horizontal mode, we have 300px (w) by 150px (h),
>> from the rules in CSS 2.1 [1,2]. Should it remain the same in vertical
>> mode,
>> or should width and height be exchanged? The description of Abstract Box
>> Layout in [3] would seem to imply the latter. (Gecko currently does this,
>> but it seems Blink does not.)
>
> This is a good question. Because the default size is mainly for plugins
> and the like, I'm leaning towards keeping it at 300px width vs. 150px
> height.
>
> However, that size exists for compat reasons and is pretty arbitrary.
> If you have *any* reason for one behavior over the other, we should
> follow that reasoning.

The main case where the logical-size interpretation might make more 
sense would be if the writing mode were also applied to the root element 
within the <iframe>. But I assume we're not going to do that -- at least 
not for non-seamless iframes -- so the contents will remain 
default-horizontal regardless of the writing mode outside.

So keeping it at physical 300px x 150px sounds OK to me. I've filed a 
Gecko bug on changing our behavior to do that:
https://bugzilla.mozilla.org/show_bug.cgi?id=1191855.

>
>> And second, should the writing mode of the <iframe> element be applied to
>> its contents? I'd have assumed "no" (and AFAICT no browser currently does
>> this), but [4] says
>>
>> # The content of replaced elements do not rotate due to the writing mode:
>> # images, for example, remain upright. However replaced content
>> involving text
>> # (such as MathML content or form elements) should match the replaced
>> element’s
>> # writing mode and line orientation if the UA supports such a vertical
>> writing
>> # mode for the replaced content.
>>
>> which could easily be read as being applicable to <iframe> content,
>> unless that content explicitly resets writing-mode to its
>> initial value. Clarification?
>
> Yeah, that needs a clarification. I think it only should apply to
> inlined replaced content like the examples mentioned, not to content
> pulled in from another document.

Sounds reasonable; given that other styles don't inherit into <iframe>s, 
it would seem odd for writing-mode to magically do so. I expect you can 
figure out some suitable wording here to eliminate the potential confusion.

Thanks,

JK

Received on Friday, 7 August 2015 09:41:57 UTC