Reader setting to allow upscaling

[SakanaKogane]

In the Display settings of the reader, complementary to the Fit display to setting, an option to allow/disallow upscaling and possibly a maximum upscale percentage for it.
Sometimes scans are small, making them more annoying to read, especially with tiny text. I would like them to fit to the container by zooming them, when they are smaller than the container. Manually zooming the page isn't viable.

EDIT: Wording.