How do I rotate an image?

Question

See also: Why is my image rotation algorithm not working?

This question isn\'t language specific, and is a math problem. I will however use

Answer 1

It seems like the example you've provided is some edge detection kernel. So if what you want to is detect edges of different angles you'd better choose some continuous function (which in your case might be a parametrized gaussian of x1 multiplied by x2) and then rotate it according to formulae provided by kigurai. As a result you would be able to produce a diskrete kernel more efficiently and without aliasing.