Re: Fwd: [css-text] Collapsing whitespace at the end of a line

Hi Pierre,

Thanks for posting this! Very interesting!

This means when using "xml:space=default" you may have to apply a 
"normalize space" function on the string before mapping it to HTML.

Best,

Andreas
Am 10.01.2017 um 05:52 schrieb Pierre-Anthony Lemieux:
> HI all,
>
> FYI. See below discussion below on the CSS reflector re: treatment of
> white-space at line break in Chrome and Edge.
>
> There is currently a strange behavior where white-spaces are
> suppressed after the line break but not before the line break.
>
> Looks like an implementation bug, as a result of which there is
> currently no equivalent to the TTML xml:space=default in these UAs.
>
> Best,
>
> -- Pierre
>
>
> ---------- Forwarded message ----------
> From: Pierre-Anthony Lemieux <pal@sandflow.com>
> Date: Mon, Jan 9, 2017 at 8:44 PM
> Subject: Re: [css-text] Collapsing whitespace at the end of a line
> To: fantasai <fantasai.lists@inkedblade.net>, "Tab Atkins Jr."
> <jackalmage@gmail.com>
> Cc: www-style list <www-style@w3.org>
>
>
>> Why preserve the space before the break but not after it? o_O
> I ran into this bizarre behavior issue while working on subtitle
> rendering. See top example at:
>
>     https://codepen.io/palemieux/pen/bgVJKO
>
> The space before the line break remains, but not the one after.
>
> I would think this is an implementation bug, unless there is a
> historical reason.
>
>> Well, sure, but wouldn't you want pre-wrap for those kinds of cases?
> Yes. Any downsides to pre-wrap?
>
> Best,
>
> -- Pierre
>
> On Sat, Jan 7, 2017 at 8:21 PM, fantasai <fantasai.lists@inkedblade.net> wrote:
>> On 08/19/2016 07:23 PM, Tab Atkins Jr. wrote:
>>> On Wed, Aug 17, 2016 at 7:19 PM, fantasai <fantasai.lists@inkedblade.net>
>>> wrote:
>>>> On 09/10/2015 01:36 PM, Tab Atkins Jr. wrote:
>>>>>
>>>>> According to <https://drafts.csswg.org/css-text/#collapse>, whitespace
>>>>> preceding a segment break is removed.  However, it appears that
>>>>> browsers instead collapse it to one space.
>>>>>
>>>>> Here's an example using 'white-space':
>>>>>
>>>>> <div style="white-space: pre-line;">a
>>>>> z</div>
>>>>>
>>>>> (Just in case the email client trims things, there's a space at the
>>>>> end of the first line, after the "a".)
>>>>>
>>>>> Here's an example using <br>:
>>>>>
>>>>> <div style="white-space: pre-line;">a <br>z</div>
>>>>>
>>>>> In both of these examples, if you highlight the "a" and then drag
>>>>> slightly rightward, you'll see it highlight a space character as well.
>>>>> This happens in both Chrome and Firefox.
>>>>>
>>>>> This sgugests that browsers are not following the "preceding" part of
>>>>> step 1 in that section, and are instead falling down to step 4, where
>>>>> runs of spaces are collapsed down to a single visible space.
>>>>>
>>>>> Is there a particular reason for this?  Should we adjust the spec to
>>>>> match implementations, or file bugs on implementations to match the
>>>>> spec?
>>>>
>>>> I'm inclined to file bugs on implementations to match the spec,
>>>> since that seems like kinda weird behavior. Why preserve the
>>>> space before the break but not after it? o_O
>>>
>>> I don't particularly care either way, tho there are cases where
>>> trailing whitespace has some significance - for example, illustrating
>>> markdown examples (where two trailing spaces indicates a hard
>>> linebreak).
>>
>> Well, sure, but wouldn't you want pre-wrap for those kinds of cases?
>>
>> [Testcase attached, fwiw.]
>>
>> ~fantasai


-- 
------------------------------------------------
Andreas Tai
Production Systems Television IRT - Institut fuer Rundfunktechnik GmbH
R&D Institute of ARD, ZDF, DRadio, ORF and SRG/SSR
Floriansmuehlstrasse 60, D-80939 Munich, Germany

Phone: +49 89 32399-389 | Fax: +49 89 32399-200
http: www.irt.de | Email: tai@irt.de
------------------------------------------------

registration court&  managing director:
Munich Commercial, RegNo. B 5191
Dr. Klaus Illgner-Fehns
------------------------------------------------

Received on Tuesday, 10 January 2017 18:58:12 UTC