- From: Jonathan Kew <jfkthame@gmail.com>
- Date: Thu, 20 Mar 2014 14:10:52 +0000
- To: "www-style@w3.org" <www-style@w3.org>
- CC: robert@ocallahan.org, James Clark <jjc@jclark.com>
On 20/3/14 04:57, Robert O'Callahan wrote: > On Thu, Mar 20, 2014 at 11:00 AM, James Clark <jjc@jclark.com > <mailto:jjc@jclark.com>> wrote: > > CSS Text says: > > Control characters (Unicode class Cc) other than tab (U+0009), > line feed (U+000A), and carriage return (U+000D) are ignored for > the purpose of rendering. > > > (This is a change from CSS 2.1, which says they are rendered as > usual.) I was wondering what the thinking is here. This requirement > conflicts with Unicode (see > http://www.unicode.org/faq/unsup_char.html) in a couple of ways: > > 1. In addition to 0x9, 0xA and 0xD, Unicode gives characters 0xB > (VT), 0xC (FF) and 0x85 (NEL) the White_Space property. Characters > with the White_Space property are supposed to be rendered as a > visible but blank space. (Of these, HTML includes only 0xC as a > space character.) > > 2. Other control characters are supposed to be rendered normally (ie > displayed with a missing glyph if not available in the font). > > > We had a discussion about this a while back within Mozilla; some people > like the idea of displaying control characters so that such 'soft > errors' in pages can be more easily detected and fixed. > > We ended up defining an internal CSS property > '-moz-control-character-visibility:visible|hidden', with initial value > hidden, but we set it to visible for devtools, plain text files, the > contents of text inputs, view-source, etc. We could easily standardize > that if other people are interested. For some further discussion, see comments (arguing both for and against such a change) in relevant mozilla bugs, such as: https://bugzilla.mozilla.org/show_bug.cgi?id=757521 https://bugzilla.mozilla.org/show_bug.cgi?id=909344 https://bugzilla.mozilla.org/show_bug.cgi?id=947588 https://bugzilla.mozilla.org/show_bug.cgi?id=963252 JK
Received on Thursday, 20 March 2014 16:00:39 UTC