histogram route

[youri-k]

URL of deployed dev instance (used for testing):

• https://___.webknossos.xyz

Steps to test:

• request [...]/data/datasets/Connectomics_Department/ROI2017_wkw/layers/color/histogram

Issues:

• fixes Add backend route to fetch sampled histogram data for each color layer #3975

---

• Adapted wk-connect if datastore API changes ?
• Needs datastore update after deployment
• Ready for review

[fm3]

This looks promising! I spoke with philipp and we came up with some change requests:

• rather than computing this for all layers at once, please have the layer name be a request parameter (like it is already shown in the steps to test list above). This will also lead to no histograms for segmentation layers (which don’t make much sense semantically, especially if sampled)
• please skip zero-values (they are likely to be caused by data being sampled outside of the real bounding box, rather than actual black tissue)
• for uint24 layers, please compute the average of the three uint8 values that are encoded for each voxel.

[daniel-wer]

As discussed, it would be really helpful for #3506, if this route would also support float layers. :)

[jstriebel]

The code LGTM, @fm3's suggestions seem to be implemented. I did not test this one, but should be fine IMO.

[jstriebel]

PS: Please add this to scalableminds/webknossos-connect#22 with a link to this PR.