Add TableOnHover and EmphasizeOnClick features

[clara-moy]

I needed it for my work and i thought it could be useful for you too

[paulbrodersen]

Hi, thanks for the pull request. On first reading, the code looks good and the writing style is very much in line with the rest of the code base, which I am very grateful for, as this makes my life very easy.

I am currently in the process of preparing a new major release. As part of that, I am re-evaluating how to handle some of the interactive features. For example, I am thinking about making annotations display on hover, rather than on click, much like "tooltips" in other libraries, and in line with your TableOnHover class. However, I don't want to support all possible combinations of emphasis, annotations, and tables with hovering or clicking. I am hence trying to figure out what are the most useful combinations and why. Could you expand a bit on your use-case and/or why you prefer to see tables on hover but emphasis on click? The latter surprised me.

[clara-moy]

Hi,

In the network graph I want, each node represent a device that communicates with other devices. The communications are represented by the edges. The mapping I use is not the default mapping because communications sometimes have intermediate devices between the source and the destination. That is why I want to see which nodes communicated with the selected node, and then I want to see the info about those nodes without loosing the information of "who did the first node communicate with". In a nutshell, I want to emphasize on click and then hover emphasized nodes to see information

[paulbrodersen]

Hi @clara-moy, thanks for the quick response, that was very helpful, and I think that both classes are a good addition.

However, having looked at your code a little bit more in detail, I think there are a few issues that I would like addressed.
For example, I think that the new classes can be implemented more succinctly through inheritance. This may require a few minor changes in the existing classes. For example, TableOnHover, really should just be along the lines of:

class TableOnClick(object):
    def __init__(self, artist_to_table, table_kwargs=None):
        ...
        self._initialize_figure_callback()

    def _initialize_figure_callback(self):
        self.fig.canvas.mpl_connect("button_release_event", self._on_release)


class TableOnHover(TableOnClick):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

    def _initialize_figure_callback(self):
        self.fig.canvas.mpl_connect("motion_event", self._on_release)

Unfortunately, I will be on vacation starting next week. If you want, I can talk you through the changes once I am back in a couple of weeks. Otherwise, I can implement these classes myself and list you as a co-author. For that, however, I would need to know your email address, either the one you are using for commiting in your own repos or your no-reply email address.

[clara-moy]

Hi,

Thank you for your corrections. I will be on holidays too so I won't have the time to do it in the next few weeks. Moreover, I'm not sure I would be able to correct the code wisely (I'm only undergraduate). It seems that you have a good idea of how the code could be improved, so I think that it would be better if you did it. My email address is c.m0y@yahoo.com. Thank you for your help and I'm sorry I can't do it myself.