I wonder if a method that returns a mask and then using the mask for get_selected_data() could be useful, since it is about 20% faster:

In [20]: %%timeit
    ...: a[(a > 50_000) & (a < 100_000)]
    ...: 
    ...: 
620 μs ± 7.79 μs per loop (mean ± std. dev. of 7 runs, 1,000 loops each)

In [21]: %%timeit
    ...: a[np.where((a > 50_000) & (a < 100_000))]
    ...: 
    ...: 
747 μs ± 31.6 μs per loop (mean ± std. dev. of 7 runs, 1,000 loops each)

For collection a helper method that gets indices or returns graphics under the selection could be useful. Not hard to implement currently, we can think about and add more helper functions later 😄

line_collection = figure[0, 0].add_line_collection(circles, cmap="jet", thickness=5)

rs = line_collection.add_rectangle_selector()

@rs.add_event_handler("selection")
def bah(ev):
    line_collection.cmap = "jet"
    ixs = ev.get_selected_indices()

    # iterate through each of the selected indices, if the array size > 0 that mean it's under the selection
    selected_line_ixs = [i for i in range(len(ixs)) if ixs[i].size > 0]
    line_collection[selected_line_ixs].colors = "w"

Chiming in here because Kushal showed this to me IRL yesterday. Pretty cool!!!!

I had two comments:

1. We once had pretty bad performance from pygfx_object.world.matrix so we ended up caching it ourselves.... maybe i should open an issue to pygfx on that. It made iterating through the list of "selectable objects" we had kinda slow.
2. Bonus points for thinking about how to do this in 3D. We didn't get to that part either....
3. Bonus points for doing this all on the GPU in WGSL and just make "highlighting" a property of your shaders ;)

Keep it going. I love to see these demos!