Specifies the direction for GdkEventScroll.
Value | Symbolic name | Description |
| 0 | Gdk::SCROLL_UP | The window is scrolled up. |
| 1 | Gdk::SCROLL_DOWN | The window is scrolled down. |
| 2 | Gdk::SCROLL_LEFT | The window is scrolled to the left. |
| 3 | Gdk::SCROLL_RIGHT | The window is scrolled to the right. |