Locking B3D scaled window to certain sizes

Blitz3D Forums/Blitz3D Programming/Locking B3D scaled window to certain sizes

Is there a way in which I can create my game in a scaled window mode, i.e Graphics3D 320,240,0,3 and then only allow the user to resize the created window to certain multiples of this number? x2, x3 etc...

So the user could for example drag the window to the next size up which would be 640x480 and then again up to 1280x960 but nothing in between.

Any help would be greatly appreciated along with a possible example :)

Jason.