private void doTestTile(int x, int y, int w, int h) throws Exception {
int[] cor = new int[]{x, y};
int[] siz = new int[]{w, h};
ImageTiler t = ihdu.getTiler();
float[] tile = new float[w * h];
t.getTile(tile, cor, siz);
for (int pos_x = x; pos_x < (x + w); pos_x++)
for (int pos_y = y; pos_y < (y + h); pos_y++) {
assertEquals(getValue(pos_x, pos_y), tile[h * (pos_x - x)
+ (pos_y - y)], 0);
}