From: Arthur Gleckler <edu/mit/csail/zurich/arthur>
Date: Fri, 12 Apr 1991 00:12:11 +0000 (+0000)
Subject: Make CLEAR-POINT, DRAW-LINE-TO, DRAW-POINT, GRAPHICS-TEXT, and
X-Git-Tag: 20090517-FFI~10762
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=a26d35ef15a02e89770225025ce8e2fb3c663643;p=mit-scheme.git

Make CLEAR-POINT, DRAW-LINE-TO, DRAW-POINT, GRAPHICS-TEXT, and
POSITION-PEN all automatically call INIT-GRAPHICS if graphics hasn't
already been initialized.  CLEAR-GRAPHICS already does this.
---

diff --git a/v7/src/sicp/graphics.scm b/v7/src/sicp/graphics.scm
index 454a8fb85..bc9c54b10 100644
--- a/v7/src/sicp/graphics.scm
+++ b/v7/src/sicp/graphics.scm
@@ -1,6 +1,6 @@
 #| -*-Scheme-*-
 
-$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/sicp/graphics.scm,v 1.2 1990/11/14 14:57:58 cph Exp $
+$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/sicp/graphics.scm,v 1.3 1991/04/12 00:12:11 arthur Exp $
 
 Copyright (c) 1987, 1988, 1989, 1990 Massachusetts Institute of Technology
 
@@ -51,23 +51,29 @@ MIT in each case. |#
 
     (define graphics-device #F)
 
+    (define (init-if-necessary)
+      (if (not graphics-device)
+	  (init-graphics)))
+
     (set! clear-graphics
 	  (lambda ()
-	    (if (not graphics-device)
-		(init-graphics))
+	    (init-if-necessary)
 	    (graphics-clear graphics-device)
 	    (graphics-move-cursor graphics-device 0 0)))
 
     (set! clear-point
 	  (lambda (x y)
+	    (init-if-necessary)
 	    (graphics-erase-point graphics-device x y)))
 
     (set! draw-line-to
 	  (lambda (x y)
+	    (init-if-necessary)
 	    (graphics-drag-cursor graphics-device x y)))
 
     (set! draw-point
 	  (lambda (x y)
+	    (init-if-necessary)
 	    (graphics-draw-point graphics-device x y)))
 
     (set! graphics-available?
@@ -76,6 +82,7 @@ MIT in each case. |#
 
     (set! graphics-text
 	  (lambda (text x y)
+	    (init-if-necessary)
 	    ;; Accepts different parameters on Chipmunks.
 	    (graphics-draw-text graphics-device x y text)))
 
@@ -90,6 +97,7 @@ MIT in each case. |#
 
     (set! position-pen
 	  (lambda (x y)
+	    (init-if-necessary)
 	    (graphics-move-cursor graphics-device x y)))
 
 ))
\ No newline at end of file