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Apple's SVG patent #US5379129

From: Daniel Phillips <phillips@bonn-fries.net>
Date: Wed, 3 Oct 2001 20:38:59 +0200
To: www-patentpolicy-comment@w3.org
Message-Id: <20011003183901Z16346-17200+337@humbolt.nl.linux.org>
Here are some details on Apple's patent listed with their RAND claims in the 
W3C's now-finalized SVG standard:

  http://www.delphion.com/details?&pn=US05379129__
  US5379129: Method for compositing a source and destination image using a 
  mask image
  Jan. 3, 1995

Here is the summary:

  This invention provides a method for compositing a source image and a   
  destination image using a mask image to produce a result image in a digital 
  image processing system. The method is, on a pixel-by-pixel basis, using 
  the mask image to select between the source and destination images: where a 
  black color value for a mask pixel selects the color value of the 
  corresponding pixel of the source image; and a white color value for a mask 
  pixel selects the color value of the corresponding pixel of the destination 
  image; and where an intermediate color value for a mask pixel selects a 
  weighted average between source and destination pixel color values. The 
  calculations of the weighted average color value are done in color space, 
  such as on a color component by color component basis. The result image can 
  be displayed or stored for further use. This method can be described in 
  boolean expression according to the formula: 

    result=((1-mask)*source)+(mask*destination).

So this is an example of the worst kind of patent: a patent on a mathematical 
expression.  Furthermore, a particularly obvious one that many, including 
myself, have been using for years prior to the date of Apple's patent.

Words fail me at this point.  Please draw your own conclusions.

--
Daniel
Received on Wednesday, 3 October 2001 14:39:05 GMT

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