.. ocv:function:: int getMouseWheelDelta(int flags)
-.. ocv:cfunction:: CV_GET_WHEEL_DELTA(flags)
-
:param flags: The mouse callback flags parameter.
For regular mice with a scroll-wheel, delta will be a multiple of 120. The value 120 corresponds to a one notch rotation of the wheel or the threshold for action to be taken and one such action should occur for each delta.
For EVENT_MOUSEWHEEL positive and negative values mean forward and backward scrolling, respectively.
For EVENT_MOUSEHWHEEL, where available, positive and negative values mean right and left scrolling, respectively.
+With the C API, the macro CV_GET_WHEEL_DELTA(flags) can be used alternatively.
+
.. note::
Mouse-wheel events are currently supported only on Windows.