Rational numbers can show sign in denominator rather than numerator (e.g. "1/-2" vs "-1/2")

[ColibriP2]

I noticed in JAlbum which uses Metadata-extractor that Exposure Bias Value is displayed 1/-3 EV instead of -1/3 EV.
The -2/3 value is well handled. I have attached a jpeg showing the problem.

[jefftucker1952]

I can add that Windows File Explorer Properties displays it as -0.3 step, as expected. If I take ColibriP2's image and "change" the value in something like EXIF Pilot, just re-entering the same value, metadata-extractor no longer chokes on it, and shows -0.3 EV. Not sure what's buried in the original that's throwing it for a loop.

[drewnoakes]

Exif stores rational numbers as two signed integers. In your original image, the denominator must be negative.

We could have the Rational toString method normalise the signs.

[drewnoakes]

Also discussed in https://jalbum.net/forum/thread.jspa?messageID=364782&tstart=0

[drewnoakes]

Note that in general, a nicer presentation of Rational values can be obtained via Rational.toSimpleString. That's not the default, however, as it can lose some information relative to toString, and it has a longer running time (https://en.wikipedia.org/wiki/Euclidean_algorithm).

In the original issue, JAlbum could sniff for instances of Rational values and call toSimpleString, which will handle the above case and others (such as converting 0/100 to 0, 7/21 to 1/3, and 1/5 to 0.2 etc.).