From cfbb0d3f6802e459b54524d753554b7b34191acd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mael=20Rouxel-Labb=C3=A9?=
 <mael.rouxel.labbe@geometryfactory.com>
Date: Wed, 15 Mar 2023 18:39:37 +0100
Subject: [PATCH] Simplify expression in the case of vertical lines

---
 .../include/CGAL/constructions/Straight_skeleton_cons_ftC2.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/Straight_skeleton_2/include/CGAL/constructions/Straight_skeleton_cons_ftC2.h b/Straight_skeleton_2/include/CGAL/constructions/Straight_skeleton_cons_ftC2.h
index 0e66dadecf4..a2150b871e2 100644
--- a/Straight_skeleton_2/include/CGAL/constructions/Straight_skeleton_cons_ftC2.h
+++ b/Straight_skeleton_2/include/CGAL/constructions/Straight_skeleton_cons_ftC2.h
@@ -737,8 +737,9 @@ compute_degenerate_offset_lines_isec_timeC2 ( Trisegment_2_ptr< Trisegment_2<K,
       }
       else
       {
-        num = ((l2a*l0b - l0a*l2b) * py - l0a*l2c + l2a*l0c) * sq_w0 ;
-        den = l0a*l0b*l2b - l0b*l0b*l2a + l2a*sq_w0 - l0a*sq_w0;
+        // l0b = 0, and all sq_w0 disappear
+        num = - l0a*l2b*py - l0a*l2c + l2a*l0c ;
+        den = l2a - l0a;
 
         CGAL_STSKEL_TRAITS_TRACE("Event time (degenerate, vertical) n=" << n2str(num) << " d=" << n2str(den) << " n/d=" << Rational<FT>(num,den) )
       }