;;;;
;;;; S c r o l l c a n v a s . s t k 	  --  Scroll Canvas composite widget
;;;;
;;;; Copyright © 1993-1998 Erick Gallesio - I3S-CNRS/ESSI <eg@unice.fr>
;;;; 
;;;; Permission to use, copy, and/or distribute this software and its
;;;; documentation for any purpose and without fee is hereby granted, provided
;;;; that both the above copyright notice and this permission notice appear in
;;;; all copies and derived works.  Fees for distribution or use of this
;;;; software or derived works may only be charged with express written
;;;; permission of the copyright holder.  
;;;; This software is provided ``as is'' without express or implied warranty.
;;;;
;;;; $Id: Scrollcanvas.stklos 1.3 Sun, 23 Aug 1998 20:43:58 +0200 eg $
;;;;
;;;;           Author: Erick Gallesio [eg@kaolin.unice.fr]
;;;;    Creation date: 25-Mar-1995 11:03
;;;; Last file update: 20-Aug-1998 17:38

(require "Basics")

(select-module STklos+Tk)

;=============================================================================
;
; 			< S c r o l l - c a n v a s >
;
;=============================================================================

;;;;
;;;; Resources
;;;;


;;;;
;;;; Class definition
;;;;

(define-class <Scroll-canvas> (<Tk-composite-widget> <Canvas>)
  ((canvas 	  :accessor     canvas-of)
   (h-scrollbar	  :accessor     h-scrollbar-of)
   (v-scrollbar	  :accessor     v-scrollbar-of)
   (h-scroll-side :accessor     h-scroll-side
		  :allocation   :virtual
		  :init-keyword :h-scroll-side
		  :slot-ref     (lambda (o) 
				  (STk:h-scroll-side (slot-ref o 'h-scrollbar)))
		  :slot-set!    (lambda (o v)
				  (STk:h-scroll-side-set! 
				      (slot-ref o 'h-scrollbar) v)))
   (v-scroll-side :accessor     v-scroll-side
		  :allocation   :virtual
		  :init-keyword :v-scroll-side
		  :slot-ref     (lambda (o)
				  (STk:v-scroll-side (slot-ref o 'v-scrollbar)))
		  :slot-set!    (lambda (o v)
				  (STk:v-scroll-side-set! 
				      (slot-ref o 'v-scrollbar) v)))
   ;; Non allocated slots
   (background   :accessor     background
		 :init-keyword :background
		 :allocation   :propagated
		 :propagate-to (frame canvas h-scrollbar v-scrollbar))
   (border-width :accessor     border-width 
		 :allocation   :propagated
		 :init-keyword :border-width
		 :propagate-to (frame))
   (relief	 :accessor     relief
		 :init-keyword :relief
		 :allocation   :propagated
		 :propagate-to (frame))))

;;;;
;;;;  <Scroll-canvas> methods
;;;;

(define-method initialize-composite-widget ((self <Scroll-canvas>) initargs parent)
  (let* ((hs (make <Scrollbar> :parent parent :orientation "horizontal"))
	 (vs (make <Scrollbar> :parent parent :orientation "vertical"))
	 (c  (make <Canvas>    :parent parent)))
    ;; Set internal true slots 
    (slot-set! self 'Id	          (slot-ref c 'Id))
    (slot-set! self 'canvas       c)
    (slot-set! self 'h-scrollbar  hs)
    (slot-set! self 'v-scrollbar  vs)

    ;; Place internal widgets
    (grid hs :row 0 :column 1 :sticky "we")
    (grid c  :row 1 :column 1 :sticky "nswe")
    (grid vs :row 1 :column 2 :sticky "ns")
    (grid 'rowconf    parent 1 :weight 1)
    (grid 'columnconf parent 1 :weight 1)

    ;; Attach command to scrollbar and canvas
    (slot-set! c 'x-scroll-command (lambda l (apply (slot-ref hs 'Id) 'set l)))
    (slot-set! c 'y-scroll-command (lambda l (apply (slot-ref vs 'Id) 'set l)))

    (slot-set! hs 'command (lambda args (apply (slot-ref c 'Id) 'xview args)))
    (slot-set! vs 'command (lambda args (apply (slot-ref c 'Id) 'yview args)))
))

(provide "Scrollcanvas")

#|
   Example:

	(define c (make <Scroll-Canvas> :scroll-region '(-1000 -1000 1000 1000)))
        (define r (make <Oval> :coords '(0 0 300 300) :fill "blue" :parent c))
	(pack c :expand #t :fill "both")
|#