# In a vega visualization is it possible to modify a signals value from mark's trigger?
**URL:** https://discuss.elastic.co/t/in-a-vega-visualization-is-it-possible-to-modify-a-signals-value-from-marks-trigger/287239
**Category:** Kibana
**Tags:** vega
**Created:** [October 20, 2021, 11:32pm UTC](https://discuss.elastic.co/t/in-a-vega-visualization-is-it-possible-to-modify-a-signals-value-from-marks-trigger/287239 "2021-10-20T23:32:11Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@nsimi](https://discuss.elastic.co/u/nsimi)
#### Post date: [October 20, 2021, 11:32pm UTC](https://discuss.elastic.co/t/in-a-vega-visualization-is-it-possible-to-modify-a-signals-value-from-marks-trigger/287239/1 "2021-10-20T23:32:11Z")
Hello All,
I am working with a force directed graph, and want to be able to zoom in and out on it, as a result I need to know the min/max value of x/y which are computed as part of the triggers on the mark, so I would like to hook in there and update a signal's value when this happens does anyone know if you can alter a signal's value from a trigger of a mark?
Thank you!
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### Author:  [@bhavyarm](https://discuss.elastic.co/u/bhavyarm)
#### Post date: [October 25, 2021, 9:31pm UTC](https://discuss.elastic.co/t/in-a-vega-visualization-is-it-possible-to-modify-a-signals-value-from-marks-trigger/287239/2 "2021-10-25T21:31:13Z")
@nyuriks can we please get some help here please?
Thanks,
Bhavya
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### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [November 22, 2021, 9:31pm UTC](https://discuss.elastic.co/t/in-a-vega-visualization-is-it-possible-to-modify-a-signals-value-from-marks-trigger/287239/3 "2021-11-22T21:31:46Z")
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