Currently the crop higher limits are inclusive too which contradicts
the documentation as it says that if Left and Right are both 50, it
will result in a zero-sized image. And the result is one pixel out of
the crop gizmo, which is another hint that this is not intended.

In "Full Frame" experimental mode it's two pixels short because of
a misuse of BLI_rcti_isect_pt as it considers max limits inclusive.