[Evolis] Fix output canvas to size

[pc-coholic]

We could try to see if this is still a problem with the newer (and way larger) Evolis-SDK - but my gut feeling (and Evolis support) are saying: nope.

Evolis printers will freak out and print all kinds of screwed up and scaled documents, if the print-bitmap is not exactly 1016x648 pixels (@ 300dpi for most printers such as an Primacy printer) or a multiple thereof (2032x1296 @ 600 dpi for an Agila printer); there are supposedly even 1200dpi printers available.

Since users have already entered random dpi to scale their print-jobs up or down to get closer to that magic size, we probably need to either introduce a potentially breaking change or take a guess what they are actually using (such as rounding to the nearest 100. 298dpi -> 300dpi. 305dpi->300dpi).

From a technical POV, I am impartial to either creating a appropriately sized canvas of 1016x648 @ 300 dpi (or more - as discussed above) and then drawing our content over that canvas - making sure to not extend it or to render our content; cropping it to the max allowable size/padding it to the proper size.

[raphaelm]

I remember that it didn't even work with the documented Canvas size for me. If someone wants to do another round of experiments, sure. Or we deprecate evolis at some point if we don't like the new sdk...