;;;;
;;;; E x a m p l e 1 .  s t k
;;;;
;;;; Copyright © 1994-1999 Erick Gallesio - I3S-CNRS/ESSI <eg@unice.fr>
;;;; 
;;;; Permission to use, copy, modify, distribute,and license this
;;;; software and its documentation for any purpose is hereby granted,
;;;; provided that existing copyright notices are retained in all
;;;; copies and that this notice is included verbatim in any
;;;; distributions.  No written agreement, license, or royalty fee is
;;;; required for any of the authorized uses.
;;;; This software is provided ``AS IS'' without express or implied
;;;; warranty.
;;;;
;;;;           Author: Erick Gallesio [eg@kaolin.unice.fr]
;;;;    Creation date:  5-Aug-1994 11:11
;;;; Last file update:  3-Sep-1999 20:08 (eg)


(require "Canvas")

;;;; Create canvas
(define c (make <Canvas>))
(pack c)

;;;; Create items
(define r1 (make <Rectangle> :parent c :coords '(  0   0  50  50) :fill "blue"))
(define r2 (make <Rectangle> :parent c :coords '( 50  50 100 100) :fill "red"))
(define o1 (make <Oval>      :parent c :coords '(100 100 150 150) :fill "blue"))
(define o2 (make <Oval>      :parent c :coords '(150 150 200 200) :fill "red"))


;;; Define some families
(define rectangles (make <Canvas-group> :parent c))
(define ovals      (make <Canvas-group> :parent c))
(define blue	   (make <Canvas-group> :parent c))
(define red	   (make <Canvas-group> :parent c))

;;;; And add members of these families
(add-to-group rectangles r1 r2)
(add-to-group ovals      o1 o2)
(add-to-group blue       r1 o1)
(add-to-group red        r2 o2)

;;;; Work with group
(move rectangles 100 100)
(move ovals -100 -100)
(move blue 100 0)
(destroy red)

;;;; Find the items of a group
(format #t "items of group blue ~s\n" (items-of-group blue))

;;;; delete an item of a group
(delete-from-group blue r1)
(format #t "items of group blue ~s\n" (items-of-group blue))
(destroy blue)

;;; Only the blue square (r1) is alive....