[WF-General] License stuff. Fun!

Karsten-O. Laux klaux at rhrk.uni-kl.de
Wed Apr 10 15:59:09 PDT 2002

you wrote:

> I talked to Eben Moglen, the FSF's lawyer about this.  PNGs count as
> transparent formats for images.  This is a different standard than the
> GPL.  We (the FSF) are considering whether and how to change this for
> future versons of the GFDL.
> Moglen says that one can take a layered image distributed under the GFDL
> and release a PNG version without also distributing the layered
> version.  As I see it, this is incentive to require GFDL 1.1 *or
> greater*, since we may change this at some point.

quoting the GFDL text:

" A copy made in an otherwise Transparent file format whose markup has been
  designed to thwart or discourage subsequent modification by readers is not
  Transparent. A copy that is not "Transparent" is called "Opaque". "

According to this phrase a png derived from a layered image file is an 
"opaque copy" in the sense of the GFDL.

Reason: The process of combining the different original layers to a single 
plane is definitely a way to 'thwart' any subsequent modifications of the 
image content. Despite the fact that the visual information is the same, the 
possibilities to edit the image are dramatically limited in comparison to the 
original layered image. 

The situation is comparable to TeX v. Postscript format. You may be able to 
change a postscript file to fit your needs, but this is very hard, if not 
impossible. So in my eyes the layered image is comparable to the LaTeX 
source, while the combined image as png is comparable to the rendered 
postscript file.


Karsten-O. Laux 
klaux at rhrk.uni-kl.de

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