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Re: Transformed Pointer Coordinates?

From: Rik Cabanier <cabanier@gmail.com>
Date: Tue, 12 Feb 2013 10:44:20 -0800
Message-ID: <CAGN7qDDqMpCmLu2s17bhupmsS4MaiBsVJCMW2rxpZKHFru--0Q@mail.gmail.com>
To: Dirk Schulze <dschulze@adobe.com>
Cc: "robert@ocallahan.org" <robert@ocallahan.org>, Jacob Rossi <Jacob.Rossi@microsoft.com>, "Tab Atkins Jr." <jackalmage@gmail.com>, Simon Fraser <smfr@me.com>, Doug Schepers <schepers@w3.org>, "public-pointer-events@w3.org" <public-pointer-events@w3.org>, "public-fx@w3.org" <public-fx@w3.org>, www-style list <www-style@w3.org>
On Tue, Feb 12, 2013 at 10:32 AM, Dirk Schulze <dschulze@adobe.com> wrote:

>
> On Feb 12, 2013, at 9:29 AM, Rik Cabanier <cabanier@gmail.com> wrote:
>
> > I agree. The vast majority of people are just interested in the 2d
> transform.
>
> At the moment yes. And for Pointer events you are probably not interested
> in a 3D point as well. I think we all agree in that. When it comes to the
> interface description, I don't see a reason to create two different
> interfaces. Better to make z=0 and w=1.
>

One reason is that it's significantly easier to specify and implement the
2d case.
As you know, the specification is unclear exactly how perspective and
transform-style are implemented. The 3D version of this API will need to
know all the transformations so it can be implemented correctly.


>
> >
> > Another issue with 3d is how transform-style [1] is treated.
> > for intstance:
> > <div id="a">
> > <div style="transform: rotate3d(...); transform-style: preserve-3d">
> > <div id="b" style="transform: rotate3d(...); transform-style: flat">
>
>
> >
> > Does it make sense to transform point between a and b?
>
> For NodeToNode transformation it probably does not make sense and an
> DOMException should be raised. For node to page, I think, WebKit still
> returns a 2D point at the moment.
>
> Greetings,
> Dirk
>
> > 1: http://www.w3.org/TR/css3-transforms/#transform-style-property
> >
> > On Tue, Feb 12, 2013 at 1:59 PM, Robert O'Callahan <robert@ocallahan.org>
> wrote:
> > Maybe I'm wrong but I feel like it would be best to keep 2D points and
> 3D points as separate interfaces. We don't want Web authors to wonder what
> "z" and "w" mean for the result of convertPointFromNode.
> >
> >
> > Rob
> > --
> > Wrfhf pnyyrq gurz gbtrgure naq fnvq, “Lbh xabj gung gur ehyref bs gur
> Tragvyrf ybeq vg bire gurz, naq gurve uvtu bssvpvnyf rkrepvfr nhgubevgl
> bire gurz. Abg fb jvgu lbh. Vafgrnq, jubrire jnagf gb orpbzr terng nzbat
> lbh zhfg or lbhe freinag, naq jubrire jnagf gb or svefg zhfg or lbhe fynir
> — whfg nf gur Fba bs Zna qvq abg pbzr gb or freirq, ohg gb freir, naq gb
> tvir uvf yvsr nf n enafbz sbe znal.” [Znggurj 20:25-28]
> >
>
>
Received on Tuesday, 12 February 2013 18:44:50 GMT

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