public RawPixel(RawMap <T> map)
: this(map, 0, 0, map.Width *map.Height)
{
}
public RawPixel(RawMap <T> map, int x, int y)
: this(map, x, y, map.Width *map.Height)
{
}
public RawPixel(RawMap <T> map, int x, int y, int limit)
{
_map = map;
_limit = limit;
_index = y * map.Width + x;
}