Turning off mouse adjustment of contrast and brightness

Is it possible to turn off the left mouse button adjustment of contrast and brightness in the Segment Editor? When manually painting a segment I keep accidentally changing the values and it is driving me up the wall!

This would indeed be a very useful feature to be able to “lock” window/level for a given volume, but I don’t think it is possible right now, unfortunately.

We’ve added this recently to the nightly version. See https://www.slicer.org/wiki/Documentation/Nightly/ScriptRepository#Disable_certain_user_interactions_in_slice_views

Currently there is no graphical user interface to activate this, so you have to write 2-3 lines of Python code (get list of slice views from the layout manager, iterate through all of them and disable interactions that you don’t need).

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Excellent news! I think this deserves an announcement, unless I missed it. Thank you!

I have to say that for some of the use cases I have in mind, it would be a lot more convenient to toggle these properties (or at least w/l) on the volume node, not for individual viewers.

I agree that locking W/L of volume display nodes could be useful, too. Ultimately, I think the most useful would be to have better mouse mode management (so that you could choose the mouse drag-and-drop to do nothing).

Do you have a specific use case where per-volume W/L locking would be preferred over disabling W/L adjustment by drag-and-drop in all views?

Yes, I do!

In one of our use cases, we do Standardized Uptake Value (SUV) correction for the PET data. While viewing SUV images, since the measurements are more or less normalized, W/L is fixed for the given tracer at certain level. It should never be changed while reviewing the data. Here is the code in the plugin that sets W/L based on the tracer for an SUV volume loaded:

As you understand, it will be quite cumbersome to keep W/L settings fixed with the current functionality. But I still think it is better than nothing, and I definitely understand there are situations where it is important and convenient to keep W/L fixed on a per-viewer basis.

I’ve added window/level locking in Volumes module (r26142). It’ll available in tomorrow’s nightly build. Let me know if you have any comments or suggestions.

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Thanks a lot @lassoan! It works as expected, and I made a PR to leverage this feature in the PET SUV DICOM plugin: https://github.com/QIICR/Slicer-PETDICOMExtension/pull/6.

I believe this feature will be very useful for quantitative imaging applications! :thumbsup:

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