XPLMHandleMouseWheel f

XPLMHandleMouseWheel_f

typedef int (* XPLMHandleMouseWheel_f)(
                                   XPLMWindowID         inWindowID,    
                                   int                  x,    
                                   int                  y,    
                                   int                  wheel,    
                                   int                  clicks,    
                                   void *               inRefcon);    

The SDK calls your mouse wheel callback when one of the mouse wheels is turned within your window. Return 1 to consume the mouse wheel clicks or 0 to pass them on to a lower window. (You should consume mouse wheel clicks even if they do nothing if your window appears opaque to the user.) The number of clicks indicates how far the wheel was turned since the last callback. The wheel is 0 for the vertical axis or 1 for the horizontal axis (for OS/mouse combinations that support this).