Index: pcb_draw.c
===================================================================
--- pcb_draw.c	(revision 7400)
+++ pcb_draw.c	(revision 7401)
@@ -4,7 +4,17 @@
 
 static void draw_thick_line(image_t * dst, int x1, int y1, int x2, int y2, double vx, double vy, double nx, double ny, int th)
 {
-	double x, y;
+	double x, y, ymin, ymax;
+
+	if (y1 <= y2) {
+		ymin = y1;
+		ymax = y2;
+	}
+	else {
+		ymin = y2;
+		ymax = y1;
+	}
+
 	x = x1;
 	y = y1;
 	for(;;) {
@@ -23,8 +33,10 @@
 		
 		x += vx/2.0;
 		y += vy/2.0;
-		if ((x > x2) || (y > y2))
+		if (x > x2)
 			break;
+		if ((y > ymax) || (y < ymin))
+			break;
 	}
 
 	return;