I have posted a patch for https://bugs.launchpad.net/inkscape/+bug/193926 The patch fixes the divisor to be calculated automatically by default.
Could you take a look at it and commit it?
-----Original Message----- From: Jasper van de Gronde [mailto:th.v.d.gronde@...528...] Sent: 20 April, 2009 22:00 To: Erik Dahlstrom Cc: Inkscape Devel List Subject: Re: [Inkscape-devel] The bias property for feConvolveMatrix
Erik Dahlstrom wrote:
On Wed, 08 Apr 2009 14:09:01 +0200, Jasper van de Gronde <th.v.d.gronde@...528...> wrote:
The SVG standard defines a "bias" property for feConvolveMatrix to offset the result of the filter. It specifies that this value should simply be added to the result for each channel. Implicitly the standard defines that these are premultiplied color values, however, this seems to make little sense, as the bias has very little meaning without
taking
the alpha channel into account.
Wouldn't the 'preserveAlpha' attribute[1] be sufficient to control this?
No, imagine that the image already has alpha=0.5, then adding a bias of 0.5 suddenly does not correspond to a transparent gray zero response, but rather a transparent white zero response.
... There should be some precedent, e.g:
- Opera 9.x
- Firefox 3.1
- ASV3
Unfortunately I don't have any of those installed, so if someone could help me test that would be great. I have attached a file that tests numerous cases using bias (and transparency), if someone could try it on his/her favourite renderer that would be great.