mirror method
void
mirror()
Implementation
void mirror() {
for (int x = 0; x < _bits.width; x++) {
for (int y = x + 1; y < _bits.height; y++) {
if (_bits.get(x, y) != _bits.get(y, x)) {
_bits.flip(y, x);
_bits.flip(x, y);
}
}
}
_mirrored = !_mirrored;
_version = null;
_formatInfo = null;
}