(require "clim")
(in-package :clim-user)

;; call it with 
;; (clim-user::show-painter)

(defclass lines-pane (basic-pane)
  ((x :initform 0) (y :initform 0) (mouse-pressed :initform nil)))

(defmethod initialize-instance :after ((pane lines-pane) &key &allow-other-keys)
  (setf (sheet-enabled-p pane) t))
 
(defmethod compose-space ((pane lines-pane) &key width height)
  (declare (ignore width height))
  (make-space-requirement :max-width 100000
                          :max-height 100000))

(defmethod handle-event ((pane lines-pane)
                         (event pointer-button-press-event))
  (with-slots (x y mouse-pressed) pane
    (setf x (pointer-event-x event))
    (setf y (pointer-event-y event))
    (setf mouse-pressed t)))

(defmethod handle-event ((pane lines-pane)
                         (event pointer-motion-event))
  (with-slots (x y mouse-pressed) pane
    (when mouse-pressed
      (let ((x2 (pointer-event-x event))
            (y2 (pointer-event-y event)))
        (draw-line* pane x y x2 y2)
        (setf x x2)
        (setf y y2)))))

(defmethod handle-event ((pane lines-pane)
                         (event pointer-button-release-event))
  (setf (slot-value pane 'mouse-pressed) nil))

(define-application-frame painter-frame ()
  ()
  (:pane
   (clim:make-pane 'lines-pane))
  (:geometry :width 400 :height 400))

(defun show-painter ()
  (let ((frame (make-application-frame 'painter-frame)))
    (run-frame-top-level frame)))