flipping pixels something something for ian

ian.cs

/* 
 a 2D array can easily be represented by a standard array.  given an array that has a size equal to a square number,
 reverse the order of the "rows" into a new array without changing the order of the elementes in each row.
 example:
 oldArray               newArray
 row 1 [0,1,2           row 3 [6,7,8  
 row 2  3,4,5     -->   row 2  3,4,5
 row 3  6,7,8]          row 1  0,1,2]
 */

int x = width;              // known size
int size = width * width;   // always a square
int[] newArray = new int[size];

for (int i = 0; i < width; i++) {
    for (int j = 0; j < width; j++) {
        int oldArrayPos = size - width * (i + 1);
        newArray[i * width + j] = oldArray[oldArrayPos + j];
    }
}