利用libtiff读取大型tiff文件，转换为bmp格式，实现放大，缩小，漫游，坐标查询功能。属于毛坯，还可以改进。-Large-scale use of libtiff to read tiff files, converted to bmp format, to achieve amplification, reduced, roaming, coordinate the inquiry. Are rough, but also could be improved.