From e1f93fd1129cf934d72bb7f08b747da55ab542b5 Mon Sep 17 00:00:00 2001
From: Alessandro Ranellucci <aar@cpan.org>
Date: Wed, 5 Mar 2014 00:05:26 +0100
Subject: [PATCH] Consider contour thickness when validating medial axis
segments
---
xs/src/Geometry.cpp | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/xs/src/Geometry.cpp b/xs/src/Geometry.cpp
index baf3803bb..a4ff2f24d 100644
--- a/xs/src/Geometry.cpp
+++ b/xs/src/Geometry.cpp
@@ -254,11 +254,19 @@ MedialAxis::is_valid_edge(const VD::edge_type& edge) const
Line segment1 = this->retrieve_segment(cell1);
Line segment2 = this->retrieve_segment(cell2);
if (segment1.a == segment2.b || segment1.b == segment2.a) return false;
- if (fabs(segment1.atan2_() - segment2.atan2_()) < PI/3) {
- //printf("segment1 atan2 = %f, segment2 atan2 = %f\n", segment1.atan2_(), segment2.atan2_());
- //printf(" => SAME ATAN2\n");
- return false;
- }
+ if (fabs(segment1.atan2_() - segment2.atan2_()) < PI/3) return false;
+
+ // we can assume that distance between any of the vertices and any of the cell segments
+ // is about the same
+ Point p0( edge.vertex0()->x(), edge.vertex0()->y() );
+ double dist = p0.distance_to(segment1);
+
+ // if distance between this edge and the thin area boundary is greater
+ // than half the max width, then it's not a true medial axis segment;
+ // if it's too small then it's not suitable for extrusion since it would
+ // exceed the desired shape too much (this also traps some very narrow
+ // areas caused by collapsing/mitering that we should ignore)
+ if (dist > this->width/2 || dist < this->width/10) return false;
}
return true;