[Qgis-user] Transparency for vector symbol layers

[Andreas Neumann]

Hi Benoit,

It depends. Yes - you can mix transparent and opaque features. For each 
color you can also set the opacity/transparency value.

However, if two features overlap and you use transparency on the feature 
level, you can see the features shine through - whereas when the 
transparency would be on the symbol level (which isn't implemented yet 
in QGIS) you would first composite all elements in a symbol level and 
then apply the opacity on the whole group. See 
http://www.w3.org/TR/2011/REC-SVG11-20110816/masking.html#ObjectAndGroupOpacityProperties 
for the difference. In 
http://www.w3.org/TR/2011/REC-SVG11-20110816/images/masking/opacity01.png - 
if you look at the bottom row of circles - the second pair of circles 
has the opacity on the group of two circles, whereas the third pair has 
opacity on every single element. I hope you can see the difference.

It would be very cool if QGIS could have a more fine-grained opacity - 
new opacity on symbol level and new opacity on a whole group of layers. 
It would make the cartographic options even better ;-)

Andreas

On 19.06.2015 16:40, Benoît Laurent wrote:
> Hello,
>
> I noticed this feature request : https://hub.qgis.org/issues/3438.
>
> Is it possible to have semi-transparent and opaque features within the 
> same layer ?
>
> Best regards,
>
> Benoît
>
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