Trim Empty Borders

Please consider including an option to automatically trim the blank borders from the pages when displaying. When multiple pages are present on the screen, you'd compute the worst-case margins for all pages to keep trimming consistent.

Why is this important? This makes the font size significantly larger for academic papers.

[itsjunetime]

Yeah this definitely seems like it would be useful. Probably not too tricky to implement (just need to look at each column of each rendered picture 'til you find a row that's not all the same color as the previous row), but may be difficult to do efficiently.

I can't say that this is near the top of the current priorities, but if anyone is interested in filing a PR, I would happily review it and help it along :)