+
+
+/* A utility function for event-handler functions:
+ Handles the various motion and click events related to trackballs.
+ Returns True if the event was handled.
+ */
+Bool
+gltrackball_event_handler (XEvent *event,
+ trackball_state *ts,
+ int window_width, int window_height,
+ Bool *button_down_p)
+{
+ if (event->xany.type == ButtonPress &&
+ event->xbutton.button == Button1)
+ {
+ *button_down_p = True;
+ gltrackball_start (ts,
+ event->xbutton.x, event->xbutton.y,
+ window_width, window_height);
+ return True;
+ }
+ else if (event->xany.type == ButtonRelease &&
+ event->xbutton.button == Button1)
+ {
+ *button_down_p = False;
+ gltrackball_stop (ts);
+ return True;
+ }
+ else if (event->xany.type == ButtonPress &&
+ (event->xbutton.button == Button4 ||
+ event->xbutton.button == Button5 ||
+ event->xbutton.button == Button6 ||
+ event->xbutton.button == Button7))
+ {
+ gltrackball_mousewheel (ts, event->xbutton.button, 10,
+ !!event->xbutton.state);
+ return True;
+ }
+ else if (event->xany.type == MotionNotify &&
+ *button_down_p)
+ {
+ gltrackball_track (ts,
+ event->xmotion.x, event->xmotion.y,
+ window_width, window_height);
+ return True;
+ }
+
+ return False;
+}