Method
GdkEventget_scroll_direction
since: 3.2
Declaration [src]
gboolean
gdk_event_get_scroll_direction (
const GdkEvent* event,
GdkScrollDirection* direction
)
Description [src]
Extracts the scroll direction from an event.
If event 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 gdk_event_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;
}
Available since: 3.2
Parameters
direction-
Type:
GdkScrollDirectionLocation to store the scroll direction.
The argument will be set by the function. The caller of the method takes ownership of the returned data, and is responsible for freeing it.