GDAL + Delphi, ZOOM IN and ZOOM OUT for view big image file

continued from view big image with GDAL & Delphi (TIFF, ECW, IMG. etc) (https://www.youtube.com/watch?v=QGrbau79vHM).
Adding zoom in and zoom out.
the script can be downloaded at https://drive.google.com/file/d/1Hwhggo8XOYlvbSmFq7DsA2EVk1PI6yan/view?usp=sharing

Видео GDAL + Delphi, ZOOM IN and ZOOM OUT for view big image file канала Dadang Iskandar