Allow volume loaders to parse sources directly

[Tom32i]

Feature

Allows a third way to load volumes: by directly providing the source data.

var buffer = ArrayBuffer();
var callback = function (volume) { };

BrainBrowser.VolumeViewer.volume_loaders.nifti1({
    'nii_source': buffer,
    'type': 'nifti1'
}, callback);

Why

I need to load volumes files from a secured server that requires authentification (so custom headers on HTTP requests). The BrainBrowser.loader:loadFromURL does not allow me to modify request headers easily.
So I'd rather handle the downloading on volumes files myself, and rely on the volumes loaders for their core feature: parsing and manipulating the data.

Implementation

The implementation is quite simple, generic and non-intrusive:

• It allows a third option named source (or nii_source for nifti files and header_source and raw_data_source for minc files, to follow their respective naming pattern).
• It's backward compatible.
• Tests are passing (I did not add specific tests on my feature yet though).
• I tried to be consistent with the coding style.

Questions

I'm not sure whether or not I should commit the following built files:

• build/brainbrowser-2.4.1/brainbrowser.volume-viewer.min.js
• release/brainbrowser-2.4.1.tar.gz

Final thoughts

I would have used parseNifti1Header and createNifti1Volume but they're scoped and inaccessible.

[PaulMougel]

👍

[natacha-beck]

@Tom32i : Thanks a lot. Like that it is perfect the *.min.js and the *.tar.gz will be generate and add to the next release.

[Tom32i]

Awesome, thank you.