W3C home > Mailing lists > Public > www-svg@w3.org > July 2012

Re: mask: luminance or alpha

From: Dirk Schulze <dschulze@adobe.com>
Date: Mon, 30 Jul 2012 20:20:02 -0700
To: Rik Cabanier <cabanier@gmail.com>
CC: Rik Cabanier <cabanier@adobe.com>, "Tab Atkins Jr." <jackalmage@gmail.com>, "www-svg@w3.org" <www-svg@w3.org>
Message-ID: <AAB92B46-6AF4-4F04-A230-2588EA3E1B7C@adobe.com>

On Jul 30, 2012, at 8:02 PM, Rik Cabanier <cabanier@gmail.com> wrote:

> On Mon, Jul 30, 2012 at 7:51 PM, Dirk Schulze <dschulze@adobe.com> wrote:
> 
> On Jul 30, 2012, at 7:31 PM, Rik Cabanier <cabanier@gmail.com> wrote:
> 
> > Any vector artwork created from any Adobe application, InkScape, CorelDraw and XAML.
> No, I meant content. All these products can create alpha masks as well. That doesn't count, otherwise I could say 99.99% of the vector artwork use alpha masking :).
> 
> I'm not talking about the products, but what they create.
> My original 99.99% was for SVG/PDF content, but I think it applies to other vector content as well (Flash excluded).
I am just saying that this is not an argument. And when a platform just supports one possibility but not the other, then of course you just find content with that technology - everything else would be stupid. So your number of 99.99% doesn't help at all. And again to "what they create": all these tools can create alpha masks as well.

> 
>  
> No seriously, most people I spoke with thought that masking would operate on the alpha channel initially. It just seems to be more intuitive. However, in SVG we will actually support both!
> 
> Did you talk to graphic designers, or people that design web pages or browsers?
> My issue is not with having both; it's with having them being inconsistent + having a default that is rarely used for vector data 
I am talking to people on IRC that blame the implementation to be wrong. I replied on bug reports that were created because of the same misunderstanding. I assume that they are content creators, otherwise they wouldn't try to create content :P

>  
> 
> 
> > My number does not include Flash since it doesn't have luminosity masks (only alpha) so people didn't have choice but I've seen workaround using pixel bender.
> Sounds like authors are already more familiar with alpha masks.
> 
> No, some advanced flash designers are familiar with working around alpha mask's limitations because they want luminosity.
That might be. On SVG a lot people tried to do the opposite and can't understand why luminance is used. It is of course hard to say if one or the other side is the majority. My experience is that most people try to use alpha masking first and are frustrated that their content doesn't work.

As consensus I would suggest adding an issue in the spec to ask for author feedback for a while. If we receive negative feedback, we can change it to luminance. A blog post might help to reach designers and ask them for responses. I expect to get more feedback why we don't change the default for masking to alpha in general :).

Greetings,
Dirk

>  
> 
> 
> >
> > For some operations that look like they could use alpha masks (like gradient shadows), our products still use luminosity. I can't remember the details but I can ask.
> >
> > Rik
> >
> > On Mon, Jul 30, 2012 at 5:16 PM, Dirk Schulze <dschulze@adobe.com> wrote:
> >
> > On Jul 30, 2012, at 4:57 PM, "Rik Cabanier" <cabanier@adobe.com> wrote:
> >
> > > Looking at current vector artwork, 99.99% is using luminosity.
> > That is an interesting number, where did you get this number and which vector artwork are you referring?
> >
> > Dirk
> >
> > > It's much easier to manipulate for a designer than alpha (since it's easier to visualize and since overlapping elements with alpha interact with each other)
> > >
> > > Rik
> > >
> > >> -----Original Message-----
> > >> From: Tab Atkins Jr. [mailto:jackalmage@gmail.com]
> > >> Sent: Monday, July 30, 2012 4:48 PM
> > >> To: Rik Cabanier
> > >> Cc: www-svg@w3.org
> > >> Subject: Re: mask: luminance or alpha
> > >>
> > >> On Mon, Jul 30, 2012 at 4:13 PM, Rik Cabanier <cabanier@adobe.com>
> > >> wrote:
> > >>> Last week, there was a decision to have the id-less mask have ‘alpha’
> > >>> as the default instead of ‘luminance’
> > >>>
> > >>> Can someone explain the rational for doing this again?
> > >>>
> > >>> It changes existing default behavior, is not what people want or what
> > >>> products like Illustrator and InkScape currently support.
> > >>
> > >> The idea is that this *is* what people want.  We just can't change <mask>'s
> > >> default behavior due to legacy compat.
> > >>
> > >> ~TJ
> >
> 
> 
Received on Tuesday, 31 July 2012 03:20:30 GMT

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