user can visualize approval distribution by circles

[mensch72]

when clicking a special button next to "...% agreement" in the top of the poll page, the user is shown a popup with a venn diagram showing the percentage of participants that approve each possible combination of options, restricted to those options that receive a positive share.

the layout algorithm should be this: https://github.com/benfred/venn.js described here: https://www.benfrederickson.com/better-venn-diagrams/ (including the "normalization" part)

the circles should be semitransparent and have a darkness and z-coordinate which are both decreasing from most approved to least approved (same order as on poll page), so that it becomes clear that intersections "belong" to the topmost option. circles are colored in the same way as the sliders on the poll page.

in addition, each non-abstaining voter (or if these are more than 100, each percentage of the electorate) is depicted by a small stylized figure placed in the correct region of the diagram.

overall, it could look somewhat like this:

[adrian-lison]

This looks like a really valuable feature to me.

Will have to see what threshold number of depicted voters is still fine to display, maybe it is already at less than 100... But I think the most important part anyway is to mark the user's position.
Where do we add the hint that these are only the options with positive share?

PS.: Cool algorithm! It would of course be nice if the most approved option would be in the center as far as possible, but I guess that cannot be guaranteed.

[mensch72]

small improvement: user's own avatar should not suggest a white person. maybe we can use a more neutral coloring.

[mensch72]

first version is implemented and tested. own avatar still missing. placement of labels sometimes suboptimal (if circles stick out only very slightly). next steps:

• add own avatar
• replace hard-coded text by i18n
• distinguish between N< or >=100 in legend
• distort bottom circles a bit into ellipses if sticking out only slightly, to improve visibility
• add specific suggestions for compromising at the end