Re: [css3-multicol] Test with excessively wide column-gaps

On Wed, Aug 7, 2013 at 4:50 PM, "Gérard Talbot" <www-style@gtalbot.org>wrote:

>
> Le Mer 7 aoūt 2013 18:33, Dirk Pranke a écrit :
> > On Wed, Aug 7, 2013 at 3:07 PM, Morten Stenshorne
> > <mstensho@opera.com>wrote:
> >
> >> "GĆ©rard Talbot" <www-style@gtalbot.org> writes:
> >>
> >> > We have hundreds of tests which use Ahem font and correspondent
> >> reference
> >> > test files using images. This is the first I hear about what you say.
> >> So,
> >> > this is somehow worrisome.
> >>
> >> OK, maybe my setup is weird. :)
> >>
> >> Can't say I'm too fond of the Ahem font. I try to avoid it when writing
> >> tests. I guess I've seen too many Ahem tests with expectations that not
> >> all font engines can live up to (like now). In my pessimistic mind, an
> >> Ahem rendering can only be compared with another Ahem rendering, and not
> >> with images, filled squares, etc. I usually end up using (inline-)blocks
> >> with a background instead, or if I really have to use text, I just use
> >> the default font, since I don't expect to be able to assume anything
> >> about how Ahem text is going to be rendered (or even laid out), anyway.
> >>
> >> BTW, on the computer I use now (Ubuntu something), Presto displays an
> >> ugly half pixel wide vertical stripe between the characters in your
> >> test. There are so many ways to "fail". :)
> >>
> >> > Do you have ClearType on or off? Do you use ClearType default, initial
> >> > setting?
> >>
> >> I don't think I've changed anything. I don't have access to that
> >> computer right now, so I can't tell you more. I was running Windows 7
> >> with IE10 inside a VirtualBox that runs under Debian. That might be a
> >> clue, I suppose.
> >>
> >> > Are you using a color LCD display?
> >>
> >> Yes.
> >>
> >> > Is the phenomenon still occuring in all/every ClearType Text Tuner
> >> > situations?
> >>
> >> I could check.
> >>
> >> > If you reset all IE10 settings to factory default, is there still a
> >> half
> >> > pixel offset affecting test versus reftest ?
> >>
> >> I could try that as well.
> >>
> >>
> > As another data point, in Blink (Chromium), we see a large number of test
> > failures on Mac OS 10.8 when rendering tests containing the Ahem font
> with
> > text antialiasing enabled; when I turned off antialiasing, the failures
> > went away.
> >
> > It's possible this is some weirdness in the font definitions for Ahem
> that
> > could be corrected.
>
> Hmm... I usually create reference files with images (swatch-*.png in
> /support/ folder) as associated reftest for tests using Ahem font.
>
> Could it be that anti-aliasing is affecting Ahem glyphs (or fonts only) in
> a way that is (or would be) different for adjacent .png images?
>
>
It's possible.

I should clarify that we turn off anti-aliasing only when running tests in
our test harness, in case that wasn't clear. It is on in the shipping
browsers.

-- Dirk