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|
;;
;; Somebody asked me a sample of doing simple animation in Gauche-gtk,
;; and I hacked this up. If you know better way, let me know.
;; Public domain -- use this as you like. [SK]
;; $Id: gdk-animation.scm,v 1.3 2007/01/13 01:36:29 maruska Exp $
;;
(use math.const)
(use gtk)
(define *angle* 0)
(define (draw drawable fg bg)
;; clear
(gdk-draw-rectangle drawable bg #t 0 0 100 100)
;; draw line
(let ((x (inexact->exact (round (+ 50 (* (cos *angle*) 50)))))
(y (inexact->exact (round (+ 50 (* (sin *angle*) 50))))))
(gdk-draw-line drawable fg 50 50 x y)
#t))
(define (main args)
(gtk-init args)
(let1 w (gtk-window-new GTK_WINDOW_TOPLEVEL)
(g-signal-connect w "destroy" (lambda _ (gtk-main-quit)))
(let* ((area (gtk-drawing-area-new))
(drawable #f) ;; initialized by realize callback
(fg-gc #f) ;; initialized by realize callback
(bg-gc #f) ;; initialized by realize callback
)
(gtk-widget-set-size-request area 100 100)
(gtk-container-add w area)
(g-signal-connect area "realize"
(lambda _
(set! drawable (ref area 'window))
(set! fg-gc (gdk-gc-new drawable))
(set! bg-gc (gdk-gc-new drawable))
(gdk-gc-set-foreground bg-gc
(ref (ref (ref area 'style) 'bg) 0))
))
(g-signal-connect area "expose_event"
(lambda (w event) (draw drawable fg-gc bg-gc)))
(gtk-timeout-add 10
(lambda ()
(inc! *angle* (* pi 0.02))
(when drawable (draw drawable fg-gc bg-gc))))
(gtk-widget-show area)
)
(gtk-widget-show w))
(gtk-main)
0)
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