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Re: [css-fonts] What does font-size-adjust for '0' look like?

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Wed, 18 Mar 2015 13:39:02 -0700
Message-ID: <CAAWBYDA1bqxSRLcXUpAhggUyNxcREorqAUQ2FRWP6LnEQ7nQgg@mail.gmail.com>
To: ChangSeok Oh <changseok@gnome.org>
Cc: www-style list <www-style@w3.org>
On Wed, Mar 18, 2015 at 1:22 AM, ChangSeok Oh <changseok@gnome.org> wrote:
> Hi Everyone.
> I have a simple question on font-size-adjust. [1]
> According to the spec. font-size-adjust can have ‘none’ or <number> for its
> value.
> BTW what is expected to look like where font-size-adjust is ‘0’? I checked
> Gecko(which is the only vendor supporting for the property now) treated it
> as ‘none’.
> Does it make sense? As my reading, font-size-adjust represents an aspect
> value (x-height / font-size) of a font.
> So ‘0’ might mean x-height is 0 or equivalent very small value here. Thus It
> should be same effect with 'font-size = 0px’
> I’d like to clarify this before landing a relevant patch for blink [2]
>
> Best regards.
>
> [1] http://dev.w3.org/csswg/css-fonts/#propdef-font-size-adjust
> [2] https://codereview.chromium.org/983073002/#msg23

Firefox's behavior seems unnecessary.  As you note, a font-size-adjust
value of zero just means that the x-height of all fonts should be
zero, which means the "adjusted font size" should be zero.  There's
not even a singularity there, at least using the equation in the spec.
There shouldn't be a special behavior at 0 at all here.  (Maybe it's
an accident, caused by doing a falsey check?)

So no, we probably shouldn't emulate Firefox.  The spec is clear that
"f-s-a:0" just makes everything zero sized, just like "f-s-a: .01"
makes everything really tiny.

~TJ
Received on Wednesday, 18 March 2015 20:39:56 UTC

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