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 instance takes ownership of the data, and is responsible for freeing it.