Can't load NRRD files with "spacings" in header

[MattTheCuber]

This is a very simple image, when I removed the spacings header, it works perfectly, when I add the spacings header it displays this:

Here is a simple example script:

import numpy as np
import nrrd
data = np.random.randint(0, 2, size=(20, 20, 20), dtype=np.uint8)
header = {
    "type": "uint8",
    "dimension": 3,
    "sizes": list(data.shape),
    'encoding': 'gzip',
    "spacings": [1.0, 1.0, 0.625],
}
nrrd.write("data.nrrd", data, header)

Here is the file when I cat it:

> cat data.nrrd
NRRD0005
# This NRRD file was generated by pynrrd
# on 2024-03-08 21:53:01(GMT).
# Complete NRRD file format specification at:
# http://teem.sourceforge.net/nrrd/format.html
type: uint8
dimension: 3
sizes: 20 20 20
encoding: gzip
spacings: 1 1 0.625

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[korbinian90]

Thank you for posting this!

I could reproduce the failure to open the image, but I couldn't get it to work by removing the spacings header. This is quite weird since it works in the web-version without issues: https://niivue.github.io/niivue-vscode/ Maybe there is a problem with handling compression while reading the file...

[MattTheCuber]

Yeah, I'm not sure. Very strange that the issue didn't resolve when removing the spacings from the header for you...

[korbinian90]

This issue should be fixed in the new pre-release:

[MattTheCuber]

That fixed the issue! Should I close the issue or leave it open until its fully-released?

[korbinian90]

Let's keep it open for now. I plan to release it soon after some tests (and once I get the release token working again...)

And thanks again for reporting this together with a code example!