Change opacity

[ebrehault]

When we display a WMS layer on top of another one, by default the opacity is 1, so the user only see the top layer. Is it possible to change this opacity so users can see the base layer in transparency ?

[DiegoGomezDeck]

G3M doesn't support mixing of layers with transparency, I recommend to merge the layers on the server side.

[mdelacalle]

Currently we don't support that capability because of performance. Probably in the next future we are going to add that, if you need urgently that please contact with us we can give you the workaround or our change our roadmap if was needed.

[DiegoGomezDeck]

If the WMS server support generation of PNGs with alpha channel (with a parameter such opacity or transparency) you can send this parameter using the method WMSLayer.setExtraParameter(string). The current version does support to mix layers respecting the alpha channel present in the PNGs.

[DiegoGomezDeck]

Add, to Layer class, float _transparency instance variable, and use it as an alpha factor when merging layers.

[NidhalSNSdev]

Can you give us more details to implement this solution

[mdelacalle]

Work in progress. I hope in a few time we will have this capability available

[amazingsmash]

Now Layers have an extra parameter (optional) that sets their transparency [0..1] when merging with other layers. G3MiOSDemo has an example where Spain is shown as a mix of BlueMarble layer and PNOA layer with a transparency of 0.5.

[mdelacalle]

great!

[mdelacalle]

https://github.com/glob3mobile/g3m_owm/blob/master/Shared/g3m_owm_shared/src/com/glob3mobile/g3mowm/shared/data/SimpleRasterLayerBuilder.java