diff --git a/include/geos/ggraph.h b/include/geos/ggraph.h
index 6eea1dff9..2e102a162 100644
--- a/include/geos/ggraph.h
+++ b/include/geos/ggraph.h
@@ -94,8 +94,13 @@ void __fastcall__ GraphicsString(char *myGfxString);
 #define	VIC_X_POS_OFF	24
 #define	VIC_Y_POS_OFF	50
 #define	SC_BYTE_WIDTH	40
+#ifdef __GEOS_CBM__
 #define	SC_PIX_HEIGHT	200
 #define	SC_PIX_WIDTH	320
+#else
+#define	SC_PIX_HEIGHT	192
+#define	SC_PIX_WIDTH	560
+#endif
 #define	SC_SIZE		8000
 /* VDC screen constants	*/
 #define	SCREENBYTEWIDTH		80
diff --git a/libsrc/geos-common/const.inc b/libsrc/geos-common/const.inc
index ef78d75b8..a09162b43 100644
--- a/libsrc/geos-common/const.inc
+++ b/libsrc/geos-common/const.inc
@@ -91,8 +91,13 @@ GRBANK3 		=	%00
 VIC_X_POS_OFF		=	24
 VIC_Y_POS_OFF		=	50
 SC_BYTE_WIDTH		=	40
+.ifdef __GEOS_CBM__
 SC_PIX_HEIGHT		=	200
 SC_PIX_WIDTH		=	320
+.else
+SC_PIX_HEIGHT		=	192
+SC_PIX_WIDTH		=	560
+.endif
 SC_SIZE 		=	8000
 ;128 screen size constants
 SCREENBYTEWIDTH 	=	80