CGAffineTransformMakeRotation does not render rotated image perfectly.
I have a square image containing a plus sign ( + ).
I use CGAffineTransformMakeRotation to rotate this image by 45 degrees (M_PI/4 rad)
If you rotate a plus (+) sign by 45 degrees it is supposed to look like a cross (x), and the angle between diagonal lines to be 90 degrees.
In my application, it is a little bit different than this. The angle between the diagonal lines is not exactly 90 degrees. It looks like its 88 and 92 at the adjacent, with a rough approximation.
Is this normal for CGAffineTransformMakeRotation function or is this a bug? If so what can i use instead, to rotate images?
What happens if you draw a second copy of your image at the same spot in a different color, and rotate that one by -45 degrees?
If the legs of the plus symbol don't line up, I'd say you might have some sort of bug on your hands. If they do, though, it seems more likely that you're seeing an artifact of the drawing environment -- maybe the pixels aren't perfectly square or something like that.