W3C home > Mailing lists > Public > www-svg@w3.org > February 2005

Re: rendering of boundaries of touching objects

From: Craig Northway <craign@cisra.canon.com.au>
Date: Mon, 28 Feb 2005 12:22:12 -0500
Message-ID: <42235344.4080604@cisra.canon.com.au>
To: Piers Titus van der Torren <pierstitus@gmail.com>
Cc: www-svg@w3.org


This is a known issue with the method of anti-aliasing that these 
renders use. Other anti-aliasing methods can be used but are more 
expensive, i.e. sub-pixel rendering uses more memory etc... The SVG 
working group have decided not to specify how anti-aliasing is done, and 
I don't think they will in the future. This artefact is not wanted, but 
this is a comprise made for performance.

Craig Northway

Piers Titus van der Torren wrote:

>When objects touch on a boundary (both object have the same nodes on
>the boundary) and it's rendered antialiased, with the objects filled
>without stroke, the boundary line is visible, it's a bit transparent.
>At least in most renderers it is (Adobe SVG viewer, Batik, KSVG,
>The question is, is this behavior wanted? It seems to me that if
>there's no space between regions there shouldn't be a transparenent
>This behavior is caused by the way transparency works, two shapes of
>50% opacity don't make 100% opacity, so the antialiased edges keep
>I can't think of an easy way to get rid of those lines, but if there's
>need for maybe we should think harder.
>For example this is a problem with autotracers like autotrace or the
>potrace based tracer of inkscape, where are transparent lines between
>every shape.
>see the attached file for an example.
Received on Monday, 28 February 2005 17:22:51 UTC

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