It would be helpful to have long side resizing as an option
In the older version of Gigapixel V1, 2 or 3, it can resize base on the long edge but since V4 the feature has been removed.
In the older version, it allowed to input both x & y dimension, and the software will resize it base on the long side.
I have contacted Customer services, in last year 2019 April. At that time, the Development Team told me that “they will re-implementing in some fashion in the future, but is currently not scheduled”.