Integer slope value for deskewing. The value given here is the number of pixels
of vertical ascent on 1000 horizontal pixels. That is, the tangent of the deskew angle multiplied by
1000. The slope parameter must be in the range -577 to 577; that means the maximal absolute slope
value is 30 degrees. Specifying a positive value rotates the image counter clockwise.
Integer slope value for deskewing. The value given here is the number of pixels
of vertical ascent on 1000 horizontal pixels. That is, the tangent of the deskew angle multiplied by
1000. The slope parameter must be in the range -577 to 577; that means the maximal absolute slope
value is 30 degrees. Specifying a positive value rotates the image counter clockwise.