W3C home > Mailing lists > Public > www-patentpolicy-comment@w3.org > October 2001

Re: Apple's SVG patent

From: Daniel Phillips <phillips@bonn-fries.net>
Date: Fri, 5 Oct 2001 14:44:06 +0200
To: Chris Lilley <chris@w3.org>, www-patentpolicy-comment@w3.org
Message-Id: <20011005124359Z16555-17200+756@humbolt.nl.linux.org>
On October 4, 2001 02:11 pm, Chris Lilley wrote:
> From: Les Barstow <lbarstow@vr1.com>
> > Bitmasks were being used back in the early 1980's in commercial games.
> > This patent wasn't requested until 1992.  APPLE THEMSELVES WERE USING
> > THIS IN 1984!  Must be a leftover from the "let's patent the icon" days
> > when they were fighting MS.
> 
> I agree with your general point about bitmasks or more generally alpha
> channels (where the transparency  is not a one bit, on or off state but
> represents variable opacity) being extremely well documented and
> predating the Apple patent by a considerable time. Alpha channels area
> well understood technlogy and are freely implemented in thousands of
> software products.
> 
> The Apple patent, on the other hand describes taking a pair of color
> images, call them A and B, and then using the *color* in B as the alpha
> for A when compositing over some destination.
> 
> So to expand the equation
> 
> Redresult=((1-RedB)*RedA)+(RedB*Reddestination)
> Greenresult=((1-GreenB)*GreenA)+(GreenB*Greendestination)
> Blueresult=((1-BlueB)*BlueA)+(BlueB*Bluedestination)
> 
> Notice that 'alpha' does not occur anywhere in this system of equations.
> 
> You will not find that this system of equations is used in the SVG
> specification and you are not required to use this system of equations
> to implement SVG. Thus, the patent does not apply to SVG - it is not
> "essential technology".
> 
> Of course, you should make up your own mind by reading the patent to
> verify this conclusion for yourself, but it seems very clear cut to me.

If that seems so clear, then why is Apple's patent even mentioned in the SVG 
patent statement?  It seems that this has just provided an easy excuse for 
Adobe to hold back RF licensing for whatever IP claims it may have.

I'd like to suggest that if the goal really was to prepare a specification 
unencumbered by patent claims, the SVG working group could have done much 
more in that regard.  Perhaps the presence of some members of the public and 
nonprofit organizations in the SVG working group would have helped the 
working group focus better on that goal.

--
Daniel
Received on Friday, 5 October 2001 08:44:05 GMT

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