Allow to send options directly as str

[lopezvoliver]

Adds the possibility to send options for the folium.plugins.VectorGridProtobuf directly as a string, so that a JS function may be used for conditional styling (e.g., see the second example here)

Here's an example with the normal styles:

Here's an example with conditional styling:

where options was defined as a string as follows:

options='''{
"vectorTileLayerStyles": {
"myLayer": function(f) {
var color = "#86340c";
if (f.ET >= 250) {
color = "#c49e0d";
}
if (f.ET >= 500) {
color = "#f3fe34";
}
if (f.ET >= 750) {
color = "#aefeae";
}
if (f.ET >= 1000) {
color = "#11f9fd";
}
if (f.ET >= 1250) {
color = "#698afc";
}
if (f.ET >= 1500) {
color = "#5813fc";
}
return {
fillOpacity: 1,
fillColor: color,
fill: true,
weight: 1,
color: "white",
opacity: 1,
};
}
}
}'''

• Also removed attribution since it is not being used.
• Also rearranged the order to match the one by VectorGridProtobuf ( url, layer_name, options/styles)

[giswqs]

Great improvement! Thanks.

[lopezvoliver]

I just noticed that I forgot to add my last commit to do this:

• Remove "attribution" from the docstring.
• Rearrange the order to match the one by VectorGridProtobuf ( url, layer_name, options/styles)

@giswqs Would you agree with these two changes? I would also need to make these changes in the ipyleaflet version of the function, to be consistent*

I also noticed that notebook 17 needs updating:

• The url is broken. Here's the correct one.
• It mentions that folium is not supported.
• It uses add_vector_tile_layer instead of add_vector_tile.
• The example shown doesn't give too much details about styling.

If I add an example with conditional styling in the notebook, will it work in the docs? I remember you mentioning that in the docs-build process the notebooks are executed with the folium backend.. so it should be fine?

*Note that currently conditional styling doesn't work with ipyleaflet backend (see jupyter-widgets/ipyleaflet#744)

[giswqs]

Sure. Please feel free to submit another PR