tilemovemouse.c

void
insertbefore(Client *a, Client *b)  /* insert a before b in the client list */
{
    Client **x = &selmon->clients;

    while(*x != b && *x)
        x = & (*x)->next;
    *x = a;
    a->next = b;
}

void
insertafter(Client *a, Client *b)   /* insert a after b in the client list */
{
    a->next = b->next;
    b->next = a;
}

void
tilemovemouse(const Arg *arg) {
    /* Could EnterNotify events be used instead? */
    Client *sel = selmon->sel;
    Client *c, *d;
    XEvent ev;
    int x, y;
    Bool after;

    if(!(c = sel))
        return;
    if(c->isfloating || !selmon->lt[selmon->sellt]->arrange){
        movemouse(NULL);
        return;
    }
    if(XGrabPointer(dpy, root, False, MOUSEMASK, GrabModeAsync, GrabModeAsync,
    None, cursor[CurMove], CurrentTime) != GrabSuccess)
        return;
    do {
        XMaskEvent(dpy, MOUSEMASK|ExposureMask|SubstructureRedirectMask, &ev);
        switch (ev.type) {
        case ConfigureRequest:
        case Expose:
        case MapRequest:
            handler[ev.type](&ev);
            break;
        case MotionNotify:
            x = ev.xmotion.x;
            y = ev.xmotion.y;
            after = False;
            for(d = nexttiled(selmon->clients); d; d = nexttiled(d->next)){
                if(d == c)
                    after = True;
                else if(INRECT(x, y, d->x, d->y, d->w+2*borderpx, d->h+2*borderpx)){
                    detach(c);
                    after ? insertafter(c, d) : insertbefore(c,d);
                    arrange(selmon);
                    break;
                }
            }
        }
    } while(ev.type != ButtonRelease);
    XUngrabPointer(dpy, CurrentTime);
}