WIP: add thumbnails to dicom browser

[pieper]

Based on ProjectWeek discussion:
https://projectweek.na-mic.org/PW35_2021_Virtual/Projects/mpReview/

[pieper]

Example usage here: https://youtu.be/JsKRAi9E8U0

[Punzo]

Hi @pieper what is the status of this PR?

I think it could be very useful. For example the ctkDICOMThumbnailGenerator method which returns a QImage removes a performance bottleneck when rendering > 10 thumbnails at once. (Saving to png in some cases could take from 0.01 to 0.1 sec for each thumbnail).

Please let me know if I can help with anything in integrating this PR.

[pieper]

@Punzo thanks for looking at this. I think it's ready to go if we like the current functionality but we could always improve things I guess. I'd be fine with merging it now and then adding improvements in a future PR.

[Punzo]

@Punzo thanks for looking at this. I think it's ready to go if we like the current functionality but we could always improve things I guess. I'd be fine with merging it now and then adding improvements in a future PR.

Perfect, I'll wait the merge then ! Thanks!

[pieper]

@lassoan @cpinter Can one of you have a quick look and comment if we should merge as-is to do some more tweaks?

[jcfr]

Thanks @Punzo and @pieper

I will have a look tonight or tomorrow.

[lassoan]

Looks great, I would just suggest a few improvements (that I implemented and tested already):

• Make the layout horizontal (place the image on the right instead of below) as the list tends to be narrow and the tall.
• Add an expand (double-array) button to allow show/hide of the thumbnail.
• Performance improvement: Only update the thumbnail if it is visible. I've also experimented with delayed update of the thumbnail (only updates the thumbnail when the slider does not move for 10ms), but it made it harder to find frames with browsing, so I did not end up adding this feature.

[lassoan]

@pieper I did not have right to push to your fork, so I've pushed it to my branch: https://github.com/lassoan/CTK/tree/browser-thumbnails

Probably you want to cherry-pick my commits from there. I've also implemented a few small issues.

[pieper]

These look great @lassoan 👍

Mine was just a WIP, so it's just as easy to make a new PR from your branch and work from here. Then I can retire mine.

[lassoan]

I've rebased and cleaned up the branch and submitted the new pull request: #1063, so I'm closing this one now.