# Transparent group / layers for graphical union

**URL:** <https://discourse.julialang.org/t/transparent-group-layers-for-graphical-union/59321>\
**Category:** Visualization\
**Created:** [April 15, 2021, 9:06am UTC](https://discourse.julialang.org/t/transparent-group-layers-for-graphical-union/59321 "2021-04-15T09:06:09Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![goretkin](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/goretkin/32/167_2.png) [@goretkin](https://discourse.julialang.org/u/goretkin)\
**Post date:** [April 15, 2021, 9:06am UTC](https://discourse.julialang.org/t/transparent-group-layers-for-graphical-union/59321/1 "2021-04-15T09:06:09Z")

</div>

SVG has a feature that allows grouping plot elements. This `g` tag can have its opacity adjusted, which is different than adjusting the opacity of the individual elements as demonstrated in this image from [this answer where there is more explanation](https://stackoverflow.com/a/15839144/):

![image](https://global.discourse-cdn.com/julialang/original/3X/d/c/dcb6912088a864910efb75f4fa772d802600db3d.png)

Not all graphical back-ends support such a feature, but when the back-end does, it is likely more efficient than computing the geometry of the union (though, if you want to e.g. add a border around the union, you’ll likely need to compute the geometry anyway). Do either `Plots.jl` or `AbstractPlotting.jl`/Makie support this?