A GUI toolkit for Common Lisp

CLIM, the galaxy's most advanced graphics toolkit

Tagged as tutorial

Written by Gabriel Laddel on 2016-08-11 17:00

Setting up the basic environment

We assume that you already have configured the Common Lisp environment (including Quicklisp) and that you know the basics of the Common Lisp programming. The necessary systems to load are mcclim and clim-listener, you may load them with the Quicklisp. After that launch the listener in a separate thread:

(ql:quickload '(mcclim clim-listener))
(clim-listener:run-listener :new-process t)


Finding your way around CLIM

CLIM is the global minimum in graphics toolkits. Geometry, and means of abstracting it. Switch the listener into the CLIM-INTERNALS package to get started. Type (in-package climi) in the Listener REPL.


Evaluate the 4 following forms in Slime REPL, then call (cos-animation) in the Listener REPL to demonstrate CLIM's animation capabilities. You cannot evaluate (cos-animation) in the Slime REPL, as *standard-output* is bound to the its output stream which isn't a sheet, and thus cannot be drawn on.

(in-package climi)

(defparameter *scale-multiplier* 150
  "try modifying me while running!")

(defparameter *sleep-time* 0.0001
  "modify and eval to speed or slow the animation, set to `nil' to stop")

(defun cos-animation ()
  (let* ((range (loop for k from 0 to (* 2 pi) by 0.1 collect k)) ; length of 62
         (idx 0)
          (updating-output (*standard-output*)
            (loop for x from (nth idx range) to (+ (nth idx range) (* 2 pi)) by 0.01
               with y-offset = 150
               for x-offset = (- 10 (* *scale-multiplier* (nth idx range)))
               for y-value = (+ y-offset (* *scale-multiplier* (cos x)))
               for x-value = (+ x-offset (* *scale-multiplier* x))
               do (draw-point* *standard-output*
                               :ink +green+
                               :line-thickness 3)))))
    (loop while *sleep-time*
       do (progn (sleep *sleep-time*)
                 (if (= 61 idx) (setq idx 0) (incf idx))
                 (redisplay record *standard-output*)))))

If you want to stop the animation, issue in the Slime REPL:

(setf *sleep-time* nil)

If it wasn't already obvious, you can plot w/e.

 #'tanh :min-x (- 0 pi pi) :max-x pi :min-y -1.1 :max-y 1.5 :ink +blue+)

Drawning class hierarchy

Type ,clear output history in the Listener REPL and RET to clear the screen.

"," indicates that you are activating a command. Try typing comma, then C-/ to activate completion. C-c C-c to dismiss.

Children of the class CLIMI::SHEET can be drawn on using arbitrary geometry. Try (clim-listener::com-show-class-subclasses 'sheet) in the Listener REPL to view the subclasses of it.

Commands and presentations

The name COM-whatever indicates that the function in question is a clim command, which you can define in the Slime REPL like so,

(in-package clim-listener)

;;; Runme! We will need these in a moment.
(dolist (image-name '("mp-avatar.png"
  (uiop:run-program (format nil "curl https://common-lisp.net/project/mcclim/static/media/tutorial-1/~A --output /tmp/~A" 
                            image-name image-name)))

(define-listener-command (com-ls :name t)
  ((path 'string))
  (clim-listener::com-show-directory path))

try ,ls /tmp/ -- then ,display image <SPACE> and click on one of the displayed paths to supply it as an argument. At the core of CLIM is the notion of a presentation. Objects have presentation methods, ie, some arbitrary rendering geometry, and when PRESENT'd on the screen CLIM remembers the type. Thus one can supply objects of the appropriate types as arguments to a command simply by clicking on them. Read about CLIMI::DEFINE-COMMAND in the specification to learn more. Let's define our first presentation method.

Intermixing S-expressions with the presentation types

Evaluate the forms below in the Slime REPL:

(in-package climi)

(defvar lords '("mircea_popescu" "asciilifeform" "ben_vulpes"))

(defclass wot-identity ()
  ((name :accessor name :initarg :name :initform nil)
   (avatar :accessor avatar :initarg :avatar :initform nil)))

(defmethod lord? ((i wot-identity))
  (member (name i) lords  :test #'string=))

(define-presentation-type wot-identity ())

(defun make-identity (name avatar-pathname)
  (make-instance 'wot-identity
         :name name
         :avatar avatar-pathname))

(defparameter *identities*
  (mapcar (lambda (l) (apply #'make-identity l))
          '(("mircea_popescu" #P"/tmp/mp-avatar.png")
        ("ben_vulpes" #P"/tmp/vulpes-avatar.png")
        ("asciilifeform" #P"/tmp/stas-avatar.png")
        ("Suit" #P"/tmp/suit-avatar.png")
        ("RainbowDash" #P"/tmp/rainbow-dash-avatar.png")
        ("ChaosLord" #P"/tmp/chaos-lord-avatar.png"))))

(define-presentation-method present (object (type wot-identity)
                                            (view textual-view)
                                            &key acceptably)
  (declare (ignorable acceptably))
  (multiple-value-bind (x y)
      (stream-cursor-position stream)
    (with-slots (name avatar) object      
      (draw-pattern* stream
                     (climi::make-pattern-from-bitmap-file avatar :format :png)
                     (+ 150 x)
                     (+ 30 y))
      (draw-text* stream name (+ 153 x) (+ 167 y)
                  :ink +black+
                  :text-size 20)
      (draw-text* stream name (+ 152 x) (+ 166 y)
                  :ink (if (lord? object)
                  :text-size 20))
    (setf (stream-cursor-position stream)
          (values x (+ 200 y)))

(defun eval-and-then-call-me-in-the-listener ()
  (let* ((n 8)
         (sheet *standard-output*))
    (labels ((gen (i)
                (let* ((out-and-start '(f x)))
                   for k from 0 to i
                   do (setq out-and-start 
                            (apply #'append
                                    (lambda (s)
                                      (case s
                                        ;; (x '(y f + f f + + x)) 
                                        ;; (y '(y f + f f x - - f f x))
                                        (x '(+ y f + f f + y y +))
                                        (y '(f - y f f x f f))
                                        )) out-and-start))))
                  (remove-if (lambda (sym)
                               (member sym '(x y) :test 'eq))

      (let* ((x 300) (y 300) (new-x x) (new-y y) (a 1) (step 15))
         for r in (gen n)
         do (progn (cond ((= a 1) (setq new-y (+ step y)))
                         ((= a 2) (setq new-x (- x step)))
                         ((= a 3) (setq new-y (- y step)))
                         ((= a 4) (setq new-x (+ step x))))
                   (case r
                     (f (clim:draw-line* sheet x y new-x new-y
                                         :ink clim:+blue+
                                         :line-thickness 6
                                         :line-cap-shape :round)
                        (setq x new-x y new-y))
                     (- (setq a (if (= 1 a) 4 (1- a))))
                     (+ (setq a (if (= 4 a) 1 (1+ a))))
                     (t nil)))))
      (let* ((x 300) (y 300) (new-x x) (new-y y) (a 1) (step 15))
         for r in (gen n)
         do (progn (cond ((= a 1) (setq new-y (+ step y)))
                         ((= a 2) (setq new-x (- x step)))
                         ((= a 3) (setq new-y (- y step)))
                         ((= a 4) (setq new-x (+ step x))))
                   (case r
                     (f (clim:draw-line* sheet x y new-x new-y
                                         :ink clim:+white+
                                         :line-thickness 2
                                         :line-cap-shape :round)
                        (setq x new-x y new-y))
                     (- (setq a (if (= 1 a) 4 (1- a))))
                     (+ (setq a (if (= 4 a) 1 (1+ a))))
                     (t nil))))))))

Now type (dolist (i *identities*) (present i)) at the CLIM Listener.

Try typing (lord? at the listener and then clicking on one of the identities. Add a closing paren and RET. Notice how objects can be seamlessly intermixed with S-expressions. If this example fails for you it may be that you have not recent enough version of McCLIM.


Unripe fruits. The future isn't what it used to be - some assembly required.

  • (CLIM-DEMO::DEMODEMO) (available with system clim-examples)

  • The essential machinery of a 'live' GUI builder

  • Navigator (essentially an extended `apropos')