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Author Topic: lasso selection  (Read 620 times)

apeoperaio

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lasso selection
« on: May 15, 2019, 10:25:48 am »
Dear all,
is there a way to select points in a TAChart using lasso selection?
Have a look here for an example:
https://plot.ly/javascript/lasso-selection/
https://onlinehelp.tableau.com/current/pro/desktop/en-us/inspectdata_selectiontools.htm

Has TAChart this functionality, someone has already implemented it? Or do you have any suggestion on how to implement it?
I think it is a very nice feature.
Thank you in advance,
Andrea

wp

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Re: lasso selection
« Reply #1 on: May 15, 2019, 11:26:06 am »
Has TAChart this functionality
No
someone has already implemented it?
No
Or do you have any suggestion on how to implement it?
Should be based on the ChartTools. Assuming a rectangular selection,  code can be borrowed from the ZoomDragTool. In the MouseUp event of the tool, all data points enclosed by the selection rectangle should be collected, stored in an array or list and passed to an OnSelect event.
Mainly Lazarus trunk / fpc 3.2.0 / all 32-bit on Win-10, but many more...

apeoperaio

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Re: lasso selection
« Reply #2 on: May 15, 2019, 04:50:18 pm »
Thanks @wp.
I am already using the rectangular selection but in some cases a more flexible selection (lasso) would be better.
I will look around.
Thank you.
Andrea

 

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