AGG/GIF

[Frédéric Junod]

I want to display transparent layers (PNG 24bit) with OpenLayers and IE doesn't
support it.

I will use the OpenLayers's alpha hack:
var layer = new OpenLayers.Layer.WMS("boucles", "/wms-lj2009-agg",
                                     {layers: 'boucles,m2_ligne,m2_arrets',
                                      format: 'image/png',
                                      transparent: true
                                     }, {alpha: true});


Thanks for your answers.
fredj 

PS: from the Internet Explorer 4 (sic) white paper:
"[...], Internet Explorer 4.0 provides native support for PNG [...]"

http://web.archive.org/web/20001020135127/http://www.microsoft.com/Windows/ie/press/whitepaper/iwhite/WHITE004.HTM


Le Wed, 7 Nov 2007 10:56:03 -0500,
Frank Warmerdam <warmerdam at POBOX.COM> a écrit :
> Frédéric Junod wrote:
> > Hi all,
> > 
> > Does the AGG renderer support gif ?
> > 
> > I suspect no because [1] don't mention it.
> > 
> > I've try with:
> > 
> > OUTPUTFORMAT
> >   NAME gif
> >   DRIVER "AGG/GIF"
> >   MIMETYPE "image/gif"
> > END
> > 
> > But mapserv returns:
> > "loadOutputFormat(): General error message. OUTPUTFORMAT clause references
> > driver AGG/GIF, but this driver isn't configured."
> 
> Frédéric,
> 
> I think the issue is that AGG produces 24bit output images, not 8bit paletted
> as supported by GIF.  So only 24bit image formats (PNG, JPEG) are available.
> In theory GIF could be supported by "crushing" the image down to 8bit paletted
> after rendering is complete, but I think the results would be very
> unsatisfactory in most cases.
> 
> Best regards,

-- 
Frédéric Junod
Camptocamp SA