static int[] matrixToIntArray(Matrix<Int> m) {
  int w = m.getWidth(), h = m.getHeight(), n = w*h;
  int[] a = new int[n];
  int i = 0;
    for y to h:
      for x to w:
        a[i++] = m.get(x, y);
  ret a;
}

Began life as a copy of #1004992