(in-package "SERVER-EXAMPLE")
(defun my-input-handler (display)
(xlib:event-case (display :timeout 0)
(:key-press (event-window code state)
(format t "KEY-PRESSED (Window = D) = S. (xlib:window-id event-window)
;; See Hemlock Command Implementor's Manual for convenient
;; input mapping function.
(ext:translate-character display code state))
;; Make XLIB:EVENT-CASE discard the event.
t)))
(defun server-example ()
"An example of using the SYSTEM:SERVE-EVENT function and object sets to
handle CLX events."
(let* ((display (ext:open-clx-display))
(screen (display-default-screen display))
(black (screen-black-pixel screen))
(white (screen-white-pixel screen))
(window (create-window :parent (screen-root screen)
:x 0 :y 0 :width 200 :height 200
:background white :border black
:border-width 2
:event-mask
(xlib:make-event-mask :key-press))))
;; Wrap code in UNWIND-PROTECT, so we clean up after ourselves.
(unwind-protect
(progn
;; Enable event handling on the display.
(ext:enable-clx-event-handling display #'my-input-handler)
;; Map the windows to the screen.
(map-window window)
;; Make sure we send all our requests.
(display-force-output display)
;; Call serve-event for 100,000 events or immediate timeouts.
(dotimes (i 100000) (system:serve-event)))
;; Disable event handling on this display.
(ext:disable-clx-event-handling display)
;; Get rid of the window.
(destroy-window window)
;; Pick off any events the X server has already queued for our
;; windows, so we don't choke since SYSTEM:SERVE-EVENT is no longer
;; prepared to handle events for us.
(loop
(unless (deleting-window-drop-event *display* window)
(return)))
;; Close the display.
(xlib:close-display display))))
(defun deleting-window-drop-event (display win)
"Check for any events on win. If there is one, remove it from the
event queue and return t; otherwise, return nil."
(xlib:display-finish-output display)
(let ((result nil))
(xlib:process-event
display :timeout 0
:handler #'(lambda (&key event-window &allow-other-keys)
(if (eq event-window win)
(setf result t)
nil)))
result))