Update gallery.html: read keywords from XPKeywords Exif tag

[jbsilva]

This change allows reading keywords from the XPKeywords Exif tag (0x9c9e).

The decodeUTF16LE function was added as Hugo does not parse UCS-2 encoded strings correctly.

Use keywords in filterOptions.

I made this as Hugo does not support reading IPCT and XMP tags (see gohugoio/hugo#8586), but I can easily convert them to XPKeywords using exiftool -overwrite_original "-XPKeywords<Keywords" *.jpg (the tags will be comma-separated).

[mfg92]

I am not sure about merging this. How common is the problem you are trying to solve here?

[jbsilva]

For me, it's a must have. I imagine that other people would also benefit from it, so I opened the PR.

In fact, I found your module while searching for a tool that could display exif tags.
I'm not a fan of sidecar files and manage my keywords with Lightroom.

Anyway, I'm only using XPKeywords because Hugo cannot read XMP tags yet.
This might change very soon (see commit from 15 min ago: bep/hugo@d2bfe27).

[mfg92]

Ok, I see. I would suggest just waiting until it is part of a Hugo release.
If for some reason it does not end up in Hugo, we can continue the discussion here.

BTW: I manage my image tags in Darktable, and have written a small plugin to automatically generate the sidecar files with all the necessary info on export.

[mfg92]

@jbsilva Hugo 0.130.0 has been released with migration to the new EXIF library, does this help?