psRegionForImage bound switching

[David.Robbins@…]

psRegionForImage allows the inputted upper bounds to be smaller than the lower
bounds. (or vice-versa). For example, setting x0 = 10 and x1 = 5 is valid and
this routine simply switches the two values. I don't believe that this type of
behaviour is either safe or consistent throughout region/image functions.
This issue was discussed at our meeting today and the resolution was to create
this bug.

[eugene]

before changing the code, can you give an example where this behavior would
cause a problem, assuming that the upper bounds are first adjusted for the
negative number behavior?

[David.Robbins@…]

well, my thought was simply that an incorrectly specified boundary set such as:

x0 = 10, y0 = 10
x1 = 9, y0 = 11

would be accepted. Another example after adjusting for negative indexing,

x0 = 10, y0 = 10 (max image includes 14, 14)
x1 = -8, y1 = 12
which translates to: x1 = 7, y1 = 12
would also get swapped with the lower boundary. The output of such would be:
x0 = 7, y0 = 10
x1 = 10, y1 = 12

[eugene]

I don't see a problem with either of the examples given, and I am inclined to deny this as a bug.