d3 brush: not a rectangle but a circle?

Asked Apr 09 '14 at 03:36

Active Apr 09 '14 at 03:36

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We wish to use a d3 brush to select neighobrs in a scatter plot. For this, a circle is more natural than a rectangle. I imagine a sequence of actions:

1) set the circle's center with a mouse click

2) adjust the radius with mouse motion, the x & y components of the current mouse position perhaps even implying an ellipse

In all the examples my web search finds, the brushed region is a rectangle.

Any advice, or working examples?

Thanks!

Puaul

asked Apr 09 '14 at 03:36

paul shannon

The brush behaviour as implemented in D3 only supports rectangles. – Lars Kotthoff Apr 09 '14 at 08:32
Thanks, Lars. Would my best fallback position be to provide circle or ellipse drawing on top of the scatter plot? -- which, when complete, I interrogate for its coordinates? Then find which scatter plot points intersect the new circle? – paul shannon Apr 09 '14 at 12:39
Yes, that's basically what you would have to do. – Lars Kotthoff Apr 09 '14 at 12:44
thanks, Lars! Your answer gets me working on the right problem... – paul shannon Apr 09 '14 at 23:23
No, brush in d3 can have different shapes. – VividD Apr 10 '14 at 02:10
Hi VividD. Can you point us to an example, or documentation? I would be very grateful! – paul shannon Apr 10 '14 at 13:10
Hi Paul, I know this is an old topic but did you finally succeed in using a circular brush? – Arnaud Nov 18 '16 at 13:09

d3 brush: not a rectangle but a circle?

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