persistable sclass IntArrayBitMatrix extends AbstractMatrix<Bool> is BitMatrix {
  int[] data;
  
  *(int *w, int *h) { data = new int[arrayLength()]; }
  *(int *w, int *h, int[] *data) {}
  
  int arrayLength() { ret (w*h+31)/32; }

  public Bool get(int x, int y) { ret getBitFromIntArray_littleEndian(data, y*w+x); }
  public void set(int x, int y, Bool a default true) { setBitInIntArray_littleEndian(data, y*w+x, a); }
}