get_scroll_direction

Extracts the scroll direction from an event.

If this is not of type gdk_scroll, the contents of direction are undefined.

If you wish to handle both discrete and smooth scrolling, you should check the return value of this function, or of get_scroll_deltas; for instance:

	GdkScrollDirection direction;
	double vscroll_factor = 0.0;
	double x_scroll, y_scroll;

	if (gdk_event_get_scroll_direction (event, &direction))
		{
			// Handle discrete scrolling with a known constant delta;
			const double delta = 12.0;

			switch (direction)
				{
				case GDK_SCROLL_UP:
					vscroll_factor = -delta;
					break;
				case GDK_SCROLL_DOWN:
					vscroll_factor = delta;
					break;
				default:
					// no scrolling
					break;
				}
		}
	else if (gdk_event_get_scroll_deltas (event, &x_scroll, &y_scroll))
		{
			// Handle smooth scrolling directly
			vscroll_factor = y_scroll;
		}

Parameters:

this	a Event
direction	location to store the scroll direction

Returns:

true if the event delivered a scroll direction and false otherwise