Region Selection Filter Listener
Region Selection Filter Listener
Description This is a listener which allows you to graphically select data from a rectangular region.
Threaded Yes
Memory Usage Light
Stream Support No
Added In —-

Region Selection Filter

This filter is a Listener, meaning that it can attach to a plot and allow you to click on plots to make things happen for quick exploration of different aspects of a data set. For more information on how to do this, see the Listener Tutorial. This filter is intended to select elements in a rectangular region from a plot and pass those through for other processing. The figure below shows this being used in a simple example. You can refer to it to see the different options.


The options allow you to specify formulas for the primary and secondary values as well as ranges for those. The formulas should match those in the plot that this is going to listen to. Failure to make them match can lead to very odd behavior. The ranges will only be set manually if you want a specific location. Most of the time they will be set through the graphical interface.

The "Apply Bounds" button will propagate the input elements that fall in the region through while the "Reset Bounds" button will reset the bounds to the minimum and maximum values in the input.

When the filter is attached to a plot, the region being selected is shaded as shown in the figure below. You can change the region by clicking and dragging. If you just click without dragging and you have selected the "Zoom region on click?" option, the region will move to where you clicked and be smaller than it had been before by the factor specified in the "Zoom Factor" box. If you select "Redo data on drag?", the output will be updated as you drag around. This should only be done in situations where the plots are able to refresh quickly. The example below, because it has over 160,000 data points on the left side, should not be used with this option.


NOTE: This filter does not support streams as they don't have significant meaning with listeners. Also remember that for a listener to be active, you have to add it under the Listeners tab of the plot.

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