Adding tooltips to graphviz representation

[freyam]

While working on #7919, I was looking for ways to represent the layer_type attribute in the graphviz representation. I stumbled upon the tooltip - Tooltip (mouse hover text) attached to the node, edge, cluster, or graph.

This opens up many doors to add more information 🚀

Demo

(image shows the layer_type as the tooltip)

So, on hover, we can display any kind of information we want per Layer. We can use this discussion thread to discuss what information would benefit users when they see a Task Graph.

Idea

We can show the attributes stored in collecton_annotations in the tooltip.

• This could be shape, dtype, chunksize, type, chunk_type (layer_type too) for Dask Arrays.
• This could be npartitions, columns, type, dataframe_type, series_dtypes (layer_type too) for Dask DataFrames.
• Anything else.

/cc @GenevieveBuckley @martindurant

[freyam]

I have opened a Draft PR where I will be working along with this discussion.
#7973

[freyam]

NOTE
This would only work for SVG outputs.
PNGs and PDFs are not supported.

[GenevieveBuckley]

So if we save out an .svg file, it retains the hover tooltip information?

If I remember correctly, the high level graph visualizations are saved by default as .pdf (and the low level graph visualizations are saved as .png, but we're not changing anything about the low level graphviz stuff). Perhaps we should change the high level graph default to .svg? It's worthwhile checking to see if most operating systems will be able to display svg files if double-clicked, without having to install other software.

[freyam]

So if we save out an .svg file, it retains the hover tooltip information?

Yes, true. The tooltips are stored in the .SVG image. If you open the SVG in a browser later, it would still possess the tooltips.

[martindurant]

If you open the SVG in a browser later, it would still possess the tooltips.

I would not be certain of this across OSs

[GenevieveBuckley]

If you open the SVG in a browser later, it would still possess the tooltips.

I would not be certain of this across OSs

I have a linux machine and a mac we can use for testing if need be. I'm sure we can find someone with a Windows machine if need be, too.

[GenevieveBuckley]

My personal preference would be .svg if it's easy to open on all operating systems. If it isn't easy, then I'd prefer .png to match the default format used to save the low level graph visualizations. It's also worth double checking that default filenames used to save the high & low level graphs are not the same, and adequately describe which is which.