diff --git a/src/devctxt.c b/src/devctxt.c
index e2ee2a7..130b7de 100755
--- a/src/devctxt.c
+++ b/src/devctxt.c
@@ -19,7 +19,7 @@ inline static BYTE line_clip_outcode(INT32 x, INT32 y, INT32 xmin, INT32 ymin, I
   return rc;
 }
 
-#define CPX 16  /* clipping precision in bits */
+#define CPX 4  /* clipping precision in bits */
 
 /* these macros keep the number of bits straight when doing fixed-point multiply & divide */
 #define M(a, b)  ((((a) * (b))) >> CPX)