[gsoc22] example with node/link highlighting

[mwarning]

An example that shows how to implement highlighting of nodes and links would be very nice to have.
You click on a node or link to highlight it. Keep the control key pressed to selected multiple nodes/links. Keep track of the highlighted items in a list.

(Example that implements this already: https://github.com/mwarning/MeshGraphViewer/ (does not use netjsonmap.js yet)

[mwarning]

Any news on this one?

It would be enough if there would be a way to hook into the drawing routine like done here: https://github.com/mwarning/MeshGraphViewer/blob/master/www/forcegraph/draw.js#L46

[kanu0204]

yes i want to contribute

[nemesifier]

One important thing in this regard is that we need to provide a way to highlight elements irregardless of the type of view (network graph, geographic map, indoor view).

Highlighting may include also opening the tooltip.

This can be used in conjunction with #238.