Straighten/rotate

[Sprintdriver]

Once in a while, I scan images. Some images contains two (or more) points that should have same Y-cordinate, but doesn't. Or having a horisontal line that after scanning has a slight slope.

That is, I need being able to pick two points on the picture - and after that the picture will rotate so that a horisontal line would be possible to draw between those points.

Or if there was somehow possible to select a line, that should be either vertical or horisontal.