Hi, Aleksandr
Alexey has already moved this discussion to jbosstools-dev.

Unfortunately, I do not have Webkit POC ready to hand, but I think I remember the approach. Basically, the WebKit based transformation was done via SWT BrowserFunction[1] and the performance was much worse in comparison with the DOM API. If you want to figure out how the current Xulrunner based implementation work, you should probably start with tests[2] that cover things like mapping between source jsf / jsp tags and visual part via DOM API. However, I still want to put my 2 cents in this discussion.

Let's face the bullet - JSF is dying technology, and spending any time on new development is simply nonsensical IMO. Even if eventually a better WebKit based VPE  will be created (which is doubtful because it was developed by big team ~ 10 developers for a couple of years) it will have very little value for both community and business. For now the only request from the community was - "please, leave it as is". 

If SWT will drop GTK 2 support than we will have to deprecate it on this Linux. But it worth mentioning that all Linux distros are just a couple of percents of the tools user base and our target audience ~ 85 - 90 % is Windows developers. For me it is also not clear why it is important to deprecate it right now ?  We already had this discussion and decided not to do it in 2015, so I can not come up with a reason why should it be done in 2016. Just to be clear, I am not against deprecation, I am just saying that we should think twice before doing it and get some agreement about Xulrunner future, so that we will not be returning to this discussion again and again.
 
[1] http://help.eclipse.org/kepler/index.jsp?topic=%2Forg.eclipse.platform.doc.isv%2Freference%2Fapi%2Forg%2Feclipse%2Fswt%2Fbrowser%2FBrowserFunction.html
[2] https://github.com/jbosstools/jbosstools-vpe/blob/master/tests/org.jboss.tools.vpe.base.test/src/org/jboss/tools/vpe/base/test/VpeTest.java#L340 

On Thu, Sep 29, 2016 at 8:07 AM, Aleksandar Kurtakov <akurtako@redhat.com> wrote:
Adding Max and Alexey (maybe we should move to the mailing list?) and dropping Jeff to not spam him.

----- Original Message -----
> From: "Aleksandar Kurtakov" <akurtako@redhat.com>
> To: "Ilya Buziuk" <ibuziuk@redhat.com>
> Cc: "Nick Boldt" <nboldt@redhat.com>, "Leo Ufimtsev" <lufimtse@redhat.com>, "Jeff Johnston" <jjohnstn@redhat.com>
> Sent: Thursday, 29 September, 2016 9:04:42 AM
> Subject: Re: Do we still need Xulrunner in Devstudio?
>
>
>
> ----- Original Message -----
> > From: "Ilya Buziuk" <ibuziuk@redhat.com>
> > To: "Aleksandar Kurtakov" <akurtako@redhat.com>
> > Cc: "Nick Boldt" <nboldt@redhat.com>, "Leo Ufimtsev" <lufimtse@redhat.com>,
> > "Jeff Johnston" <jjohnstn@redhat.com>
> > Sent: Wednesday, 28 September, 2016 8:23:47 PM
> > Subject: Re: Do we still need Xulrunner in Devstudio?
> >
> > Basically, jsf tags can not be displayed as-is and be parsed correctly in
> > browser like html, due to the fact that it is server side technology. So,
> > the algorithm  for VPE is the following: the content is rendered and all
> > jsf tags are parsed through a set of templates via the native DOM API which
> > is available only in particular older versions of XULRunner. So, in order
> > to use Webkit or other engine and migrate all VPE features, reimplementing
> > all of those temlpate transformations is required. Plus not to forget the
> > performance thing - processing might take a long time (I think we had some
> > WebKit POC but performance was just unacceptable). This is not a trivial
> > task at all and I do  believe that we have no resources for doing it - VPE
> > component's code base is one of the biggest (if not the biggest) across
> > tools.
>
> That's exactly the kind of info I was looking for. Can you point me to the
> transformations used for the xulrunner? Sorry for being lazy but it's
> foreing land for me so I would rather not lose time lurking around.
> Do you have a pointer to the WebKit POC? It might be interested to reach out
> to the desktop team (there is webkit developer there) with all the info so
> maybe they can hint us how to achieve what's needed if latest webkit doesn't
> fullfill the needs.
>
> > In a nutshell - after reimplementing there will be the same, or less
> > powerful,  VPE with more bugs and poor performance.
>
> That might be true now but you should think a bit further in time. In the not
> so distant future (2018 release most probably, if not 2019 for sure) SWT
> itself will drop support for running on GTK 2.x and that would be
> effectively the end of this plugin if no action taken.
>
>
> >
> > On Wed, Sep 28, 2016 at 6:42 PM, Aleksandar Kurtakov <akurtako@redhat.com>
> > wrote:
> >
> > >
> > >
> > > ----- Original Message -----
> > > > From: "Ilya Buziuk" <ibuziuk@redhat.com>
> > > > To: "Nick Boldt" <nboldt@redhat.com>
> > > > Cc: "Aleksandar Kurtakov" <akurtako@redhat.com>, "Leo Ufimtsev" <
> > > lufimtse@redhat.com>, "Jeff Johnston"
> > > > <jjohnstn@redhat.com>
> > > > Sent: Wednesday, 28 September, 2016 7:19:24 PM
> > > > Subject: Re: Do we still need Xulrunner in Devstudio?
> > > >
> > > > Actually, we planned to remove xulrunner and deprecate VPE some time
> > > > ago
> > > > and leave only VPV as a WYSIWYG html editor.
> > > As someone not familiar with the topic I don't see xulrunner and VPE
> > > deprecation that closely coupled. What is the reason for that? What's
> > > preventing to achieve it with webkit? Do you extend SWT Browser API
> > > somehow?
> > > Please give all the details you can think of so I can get better
> > > understanding of the issue/reasons.
> > >
> > > > However, as soon as we gave a
> > > > shout out about this on tools.jboss.org the first comment was:
> > > >
> > > > Nice. The reason I used JBoss Tools was the Visual Editor for JSF,
> > > > > especially for the Visual parts, which was not perfect but was good
> > > enough
> > > > > to have it. Will you have alternatives for that ? [1]
> > > >
> > > >
> > > > It was decided that we need to slow down with this process. I can not
> > > > say
> > > > if it is a high time for doing this assuming that some people actually
> > > use
> > > > it. Furthermore, some people treat it as a killer feature for JSF that
> > > only
> > > > one IDE is providing. So, we need to think twice before doing it.
> > > >
> > > >  [1] http://tools.jboss.org/blog/2015-04-02-devstudio-8.1.0.GA-
> > > for-luna.html
> > > >
> > > > On Wed, Sep 28, 2016 at 5:40 PM, Nick Boldt <nboldt@redhat.com> wrote:
> > > >
> > > > > On the Eclipse team call today, the question of why we need Xulrunner
> > > > > was brought up again.
> > > > >
> > > > > As I understand it, the only reason we still include Xulrunner is for
> > > > > the Visual Page Editor. But Alex pointed out today that Xulrunner
> > > > > only
> > > > > works on GTK2, which means a user has to explicity disable GTK3 in
> > > > > order for Xulrunner to be used, as these days GTK3 is the default
> > > > > OOTB
> > > > > implementation on the platforms we support (Fedora 24/25, RHEL7,
> > > > > etc.).
> > > > >
> > > > > So... is it time to remove Xulrunner from the Devstudio dependencies,
> > > > > if most people are not even seeing it used?
> > > > >
> > > > > Alex suggested it might be useful to set up a call to discuss this in
> > > > > more depth. Is there a good time tomorrow or Friday you guys would
> > > > > like to meet to discuss this, if it can't be resolved asynchronously
> > > > > via email?
> > > > >
> > > > > Whatever we decide here, we should make sure we announce this on the
> > > > > jbosstools-dev@ list.
> > > > >
> > > > > --
> > > > > Nick Boldt :: JBoss by Red Hat
> > > > > Productization Lead :: JBoss Tools & Dev Studio
> > > > > http://nick.divbyzero.com
> > > > >
> > > >
> > >
> > > --
> > > Alexander Kurtakov
> > > Red Hat Eclipse team
> > >
> >
>
> --
> Alexander Kurtakov
> Red Hat Eclipse team
>

--
Alexander Kurtakov
Red Hat Eclipse team