You’ll find here https://github.com/ldci/OpenCV-Xojo some code to access OpenCV3.0 functions with Xojo.
The code is under development, but you can begin to play with. Successfully tested under OSX 10.5 and Windows 10.
Regards from France
Franois, do you really mean Mac OS X 10.5, Leopard ? That is quite an old system…
OS X is OS 10, so I suspect that OS X 10.5 is really OS 10.10.5.
Oups, 10.10.5 of course