Rotating a 2D pixel array by 90 degrees

Question

I have an array of pixel data for an image. The image I am getting is already rotated to 270 degrees. So I am trying to rotate it again by 90 degrees to have the correct ima

Answer 1

This can be done without using any extra space, so called In-place matrix transposition (not exact the same). Remember to do some mirroring after the transposition.

1. If the image is square

   

2. If the image is not square

   • For non-square matrices, the algorithms are more complicated. Many of the algorithms prior to 1980 could be described as "follow-the-cycles" algorithms. That is, they loop over the cycles, moving the data from one location to the next in the cycle. In pseudocode form: