srecord noeq G22Tiling<Img extends WidthAndHeight>(Img img) {

  new L<Tile> tiles;

  // number of pixels covered by all tiles

  int pixelsCovered;

  // for each pixel: tile index+1 (or 0 for empty)

  int[] tileMatrix;

  // index = dual log of tile size, value = tile index

  //new L<IntBuffer> tilesBySize;

  // yay, extending Rect to save space

  class Tile extends Rect {

    int index;

    int color; // tile color as defined by the tiler

    *(int *index, int *color, Rect position) {

      position(position);

    }

    Rect position() { this; }

    selfType position(Rect r) {

      x = r.x; y = r.y; w = r.w; h = r.h;

      this;

    }

    S area_str() {

      ret nPixels(area());

    }

    double ratioToImage() {

      ret doubleRatio(area(), imageArea());

    }

    S percent_str() {

      ret formatDoubleX(ratioToImage()*100, 2) + "% of image";

    }

    toString {

      ret intToHex_fullLength(color) + " colored tile covering " + percent_str() +  " at " + super.toString();

    }

    // Lists of neighbors in all 4 directions (index like NESWDirection)

    // (If only a corner is touching, it's not a neighbor.)

    // Not used yet

    //Cl<Tile>[] neighbors;

  }

  int w() { ret img.w(); }

  int h() { ret img.h(); }

  int imageArea() { ret img.area(); }

  void initTileMatrix {

    tileMatrix = new int[w()*h()];

  }

  int numTiles() { ret l(tiles); }

  L<Tile> get() { ret tiles; }

}