Re: Gimp: Erased sections of images print in some cases

From: Robert Bihlmeyer (robbe@orcus.priv.at)
Date: 10/30/02 

From: Robert Bihlmeyer <robbe@orcus.priv.at>
To: Clark Mills <c.mills@auckland.ac.nz>
Date: Wed, 30 Oct 2002 11:42:26 +0100 (CET)

Clark Mills <c.mills@auckland.ac.nz> writes:

> http://c-mills.ctru.auckland.ac.nz/transparent.png
>
> If you view this image from Linux in Galeon 1.2.6 or Netscape/7.0
> all looks fine however if you print the image from within these
> applications then the _erased_ section prints as if it was never
> erased.

Cute. pngtopnm will also uncover the "erased" area. Gimp's eraser
simply modifies the alpha channel, leaving RGB channels intact. If
something later sets transparency to zero (e.g. because the output
device/format doesn't support it), the original data appears
again. Something to keep in mind.

> I let the Gimp people know this but they replied considering it a
> feature not a bug which could be the case in some/most
> circumstances, Bug #97167.

Perhaps it should be an option to the eraser to clear RGB as well.

FWIW, my Gimp (1.2.3) has ">Image>Alpha>Clear Alpha..." which will do
that for the whole layer/image. It is a standard gimp-perl plugin,
apparently. 

-- 
Robbe