[PdfToPpm] Fix the selected dimension to size with swap

(I have a bug with my last branch and I need to recreate this merge request)

Hello,

I think I find an issue in pdftoppm.

For a rotated pdf, options -scale-to-y and -scale-to-x are swapped:

For example with a rotated pdf x=200 y=100

1. We use the options: -scale-to-y 50 -scale-to-x -1
2. The generated image has width=50 and height=25
3. But with this option the expected sizes are width=100 and height=50

I found the same correction in pdftoCairo.cc and an issue #595 (closed).

I hope my analysis are right and i don't break a real functionality.

For the test I attached a pdf sample. rotated.pdf

Comment of the old merge request:

Maybe I'll submit another merge request with the same modification to pdftocairo.cc

Oliver Sander

Can you change this to use std::swap?

corentinfoucault

I add a new commit with std::swap.

An other solution can be found here: !384 (merged)