After defining a layer parameter with PF_ADD_LAYER, how do I get a handle to the layer? It's simple to get this from an expression, but I don't see where to get it from a plugin.
Even if I PF_CHECKOUT_PARAM explicitly, there doesn't seem to be any way to get from PF_ParamDef to AEGP_LayerH.
If it matters, this is during PF_Cmd_USER_CHANGED_PARAM. I can get pixel data with PF_CHECKOUT_PARAM, but I need the layer handle to look at markers on the selected layer. It seems like there the selected layer index should be in paramDef.uu.id, but it's always 0.