Re: [css-text] Rendering of control characters

On Wed, Sep 24, 2014 at 7:46 AM, Behdad Esfahbod <behdad@behdad.org> wrote:

> Hi,
>
> Currently CSS Text Module Level 3 says [0]:
>
> """
> 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.
> """
>
> AFAIU the Unicode standard says that those should be rendered like any
> other
> characters except for the ones that are considered whitespace.  This also
> lines up closely with CSS2.1 [1]:
>
> """
> Control characters other than U+0009 (tab), U+000A (line feed), U+0020
> (space), and U+202x (bidi formatting characters) are treated as characters
> to
> render in the same way as any normal character.
> """
>
> I'm asking, because this disparity requires implementations to rewrite such
> characters before passing text to a shaping engine like HarfBuzz.  This
> makes
> me wonder, why the deviation from Unicode?  If there are no good
> explanations,
> can we change that please?
>

In the recent F2F, it was resolved to change this to display Cc characters
(other than HT, LF, CR). So I believe this problem has been resolved.


>
> [0] http://www.w3.org/TR/css-text-3/#white-space-processing
> [1] http://www.w3.org/TR/CSS2/text.html#ctrlchars
>
> Cheers,
> --
> behdad
> http://behdad.org/
>
>