W3C home > Mailing lists > Public > www-svg@w3.org > June 2007

[SVG 1.1] BackgroundImage and alpha compositing

From: MenTaLguY <mental@rydia.net>
Date: Tue, 26 Jun 2007 10:58:43 -0400
To: SVG List <www-svg@w3.org>
Cc: bulia byak <buliabyak@gmail.com>, Niko Kiirala <niko@kiirala.com>
Message-Id: <1182869923.18825.11.camel@localhost.localdomain>
Hello,

I've run up against a problem with filters and the use of
BackgroundImage in SVG 1.1: the filter output is alpha-composited with
the background, which results in double-compositing if the filter itself
composites with the background (e.g. when using feBlend to get "blend
modes").  This is noticable in areas of the background which are
semi-transparent, which may be due to transparent objects, or simply
antialiasing.

See here for an illustration of the problem:

 http://www.rydia.net/~mental/www-svg/background-image-alpha-issue.svg
 http://www.rydia.net/~mental/www-svg/background-image-alpha-issue.png

Is there a way to work around this?  Ideally there would be some way for
filter output to replace part of the accumulated image rather than being
composited with it.

-mental

Received on Tuesday, 26 June 2007 14:59:12 GMT

This archive was generated by hypermail 2.3.1 : Friday, 8 March 2013 15:54:37 GMT