Milestone 1: Rotate Left and Right buttons

Your next step is to add two buttons that rotate the image on the screen by 90°. Once again, the most challenging part of this milestone is adding the functions that actually transform the GImage. Implementing these rotations is a bit tricky, since you have to figure out where each of the old pixels ends up in the new image array. Since the dimensions of the new image are inverted from the original (the new width is the old height and vice versa), you need to create a new array with the correct number of elements in each dimension. Once you have done so, you need to copy each old pixel into the correct position in the new array. This process is illustrated in Figure 1, which shows where each pixel in the first row of the old array (before) moves to the new array (after) during a 90° rotation left (or counter-clockwise).

Figure 1: Graphical depiction of rotating an image array 90° counter-clockwise (left). Note that what was previously the last column is now the first row, and what was the first row is now the first column.