Transparency in WMS
yjacolin at FREE.FR
Tue Aug 7 09:05:33 EDT 2007
Le Tuesday 07 August 2007 14:57:34 Daniel Morissette, vous avez écrit :
> Jacolin Yves wrote:
> > Le Tuesday 07 August 2007 14:37:59 Daniel Morissette, vous avez écrit :
> >> If you are using MapServer as a WMS service and expecting the
> >> transparency/opacity of a given layer to result in a 50% opaque GetMap
> >> response then that won't work.
> > Is it a limitation from mapserver or from the standard itself?
> It's a bit of both.
> The WMS spec is not clear on whether it is acceptable to return
> semi-transparent images. Section 220.127.116.11 of the WMS 1.1.1 spec talks
> about the TRANSPARENT=TRUE/FALSE GetMap parameter but that is only to
> control whether the background of the image is fully transparent or not
> and does not address the possibility of producing semi-transparent
> images. Everywhere else it suggests that pixels representing features
> are fully opaque.
> And it may also be a MapServer limitation in the sense that we may need
> to make some changes to allow MapServer to generate semi-transparent
> images... but maybe not and that works already, I just haven't checked.
Alright, thanks Daniel.
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