[MapServer-users] Mapserver>=8.0: Layer Composite Opacity

[Jeff McKenna]

Hi Dieter,

It could be possible that your MapServer installation was compiled with 
Pixman library support enabled in MapServer, which unfortunately causes 
a known bug where opacity does not work (see 
https://github.com/MapServer/MapServer/issues/5343 ).  I believe we 
should completely remove Pixman support from MapServer in a future 
release, as so many users hit this issue each year.

In other words, make sure that you set -DWITH_PIXMAN=0 when compiling 
MapServer from source.

PS. I actually used the small mapfile included in that ticket, for 
testing now with today's MapServer 8.3-dev on MS4W 5, on Windows, and 
successfully generated a proper map image (with opacity) with map2img.

thanks,

-jeff



-- 
Jeff McKenna
GatewayGeo: Developers of MS4W, & offering MapServer Consulting/Dev
co-founder of FOSS4G
http://gatewaygeo.com/



On 2024-08-07 9:53 a.m., GOGIS Dieter Zuberbühler via MapServer-users wrote:
> What happend to the 'Layer Composite Opacity' in Mapserver>=8.0? I
> tried several versions of Mapserver 8.x on Ubuntu 22.04 and 24.04 and
> had always the same result: 'Opacity on Layer Level' is ignored and the
> background layers are not visible.
> 
> I tried with map2img and phpng (swig), same result.
> 
> In the documentation it is still available and the mapfile is parsed
> correctly. I can get and set the opacity with php and it will be
> written down (save to mapfile) correctly.
> 
> Any hint, is this removed or a known problem?
> 
> Thank you in advance,
> 
> Dieter
> 
>