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Re: [css3-transforms] scale 0 on non-scaling strokes

From: Rik Cabanier <cabanier@gmail.com>
Date: Sat, 12 May 2012 23:57:04 +0300
Message-ID: <CAGN7qDBcFFQzK3p_DiNTuVMuHUv2w_bVi2o2A618W8d7baUgSQ@mail.gmail.com>
To: "Dr. Olaf Hoffmann" <Dr.O.Hoffmann@gmx.de>
Cc: public-fx@w3.org
On Sat, May 12, 2012 at 2:52 PM, Dr. Olaf Hoffmann <Dr.O.Hoffmann@gmx.de>wrote:

> Rik Cabanier:
> >All,
> >
> >on wednesday it was resolved that an element with a non-scaling stroke
> >should disappear when a scale factor goes to 0.
> >After thinking about this some more, I think that this doesn't make sense.
> >The geometry of the stroke does not scale, only the path does.
> >So, when scale goes to '0', the path would go to a line or a dot which
> then
> >should be stroked.
> >
> >If the element is skewed to 90deg, I agree that everything should
> disappear.
> >
> This can be surprising as well, because here already the fill area is not
> necessarily zero - isn't this conserved for skewing in general?

But it would be mathematically correct though.
When you skew to 90 degrees, the shape's length becomes infinite. So: area
divided by infinity becomes 0

> >I think the behavior that was agreed upon will cause rendering glitches.
> If
> >you have an animation that goes from scale(1,1) to scale(-1, 1), you will
> >see a flicker 50% into the animation.
> Following the previous discussion on this list about these
> (and other) issues, I got the impression, that the effect is intended.
> I think, the general idea about these specific 'no rendering' rules
> is to frustrate authors to force them to avoid such situations and
> applications and care about other things than non-scaling-stroke
> of 1D or 0D objects, mirroring within animation, skewing,
> non invertable matrices, compatibility with current SVG etc.
> A friendly author is expected to find no new applications, the
> editors did not see or did not like, therefore these attempts
> to restrict the usefulness of such drafts on issues, the editors
> do not like ;o)

Are you thinking of the issue with matrices in the @keyframes rule?

> Another interpretation is, that some implementations of the
> current draft are of low quality and cannot solve such situations
> in a meaningful way and these are the desperate attempts
> to hide these quality or motivation problems ;o)

There are several indications for the problem of low motivation
> to improve the current draft as well in previous discussions.
> At some point it becomes a waste of time to read CSS drafts
> and to provide comments on it - if such comments are ignored
> anyway ;o)

I don't think the comments are ignored. Maybe it just seems that way
because there was no reply on the mailing list.
There was a discussion by the CSS working group during which your proposal
was brought up. It was discussed and voted on.
It was my first time there and wasn't sure of how much I could be involved,
but I should have spoken up.

Received on Saturday, 12 May 2012 20:57:33 UTC

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