From 6643d7876930e7c6ec7df71bfc7c2b5f97a2a047 Mon Sep 17 00:00:00 2001
From: supermerill <merill@fr.fr>
Date: Fri, 7 Dec 2018 13:25:23 +0100
Subject: [PATCH] stop_at_min_width : do not extends the thin wall if it's over
 the min_width (can be toggled when calling expolygon.medial_axis).

---
 xs/src/libslic3r/ExPolygon.cpp  |  9 +++------
 xs/src/libslic3r/ExPolygon.hpp  |  2 +-
 xs/src/libslic3r/MedialAxis.cpp | 28 +++++++++++++++++++++-------
 xs/src/libslic3r/MedialAxis.hpp |  1 +
 4 files changed, 26 insertions(+), 14 deletions(-)

diff --git a/xs/src/libslic3r/ExPolygon.cpp b/xs/src/libslic3r/ExPolygon.cpp
index 87c119a04fe..bfc3d5077a0 100644
--- a/xs/src/libslic3r/ExPolygon.cpp
+++ b/xs/src/libslic3r/ExPolygon.cpp
@@ -210,12 +210,9 @@ ExPolygon::remove_point_too_near(const coord_t tolerance) {
 }
 
 void
-ExPolygon::medial_axis(const ExPolygon &bounds, double max_width, double min_width, ThickPolylines* polylines, double height) const {
-    ExPolygon simplifiedBounds = bounds;
-    simplifiedBounds.remove_point_too_near(SCALED_RESOLUTION);
-    ExPolygon simplifiedPolygon = *this;
-    simplifiedPolygon.remove_point_too_near(SCALED_RESOLUTION);
-    Slic3r::MedialAxis ma(simplifiedPolygon, simplifiedBounds, max_width, min_width, height);
+ExPolygon::medial_axis(const ExPolygon &bounds, double max_width, double min_width, ThickPolylines* polylines, double height, bool stop_at_min_width) const {
+    Slic3r::MedialAxis ma(*this, bounds, max_width, min_width, height);
+	ma.stop_at_min_width = stop_at_min_width;
     ma.build(polylines);
 }
 
diff --git a/xs/src/libslic3r/ExPolygon.hpp b/xs/src/libslic3r/ExPolygon.hpp
index 92610cc5673..cd3ab9ea7e9 100644
--- a/xs/src/libslic3r/ExPolygon.hpp
+++ b/xs/src/libslic3r/ExPolygon.hpp
@@ -43,7 +43,7 @@ class ExPolygon
     ExPolygons simplify(double tolerance) const;
     void simplify(double tolerance, ExPolygons* expolygons) const;
     void remove_point_too_near(const coord_t tolerance);
-    void medial_axis(const ExPolygon &bounds, double max_width, double min_width, ThickPolylines* polylines, double height) const;
+    void medial_axis(const ExPolygon &bounds, double max_width, double min_width, ThickPolylines* polylines, double height, bool stop_at_min_width = true) const;
     void medial_axis(double max_width, double min_width, Polylines* polylines) const;
     void get_trapezoids(Polygons* polygons) const;
     void get_trapezoids(Polygons* polygons, double angle) const;
diff --git a/xs/src/libslic3r/MedialAxis.cpp b/xs/src/libslic3r/MedialAxis.cpp
index ba3e5fdfdd1..2cd602db1fb 100644
--- a/xs/src/libslic3r/MedialAxis.cpp
+++ b/xs/src/libslic3r/MedialAxis.cpp
@@ -1360,6 +1360,18 @@ MedialAxis::build(ThickPolylines* polylines_out)
     //fusion right-angle corners.
     fusion_corners(pp);
 
+    // Loop through all returned polylines in order to extend their endpoints to the 
+    //   expolygon boundaries (if done here, it may be cut later if not thick enough)
+    if (stop_at_min_width) {
+		const ExPolygons anchors = offset2_ex(to_polygons(diff_ex(this->bounds, this->expolygon)), -SCALED_RESOLUTION, SCALED_RESOLUTION);
+        for (size_t i = 0; i < pp.size(); ++i) {
+            ThickPolyline& polyline = pp[i];
+            extends_line(polyline, anchors, min_width);
+            polyline.reverse();
+            extends_line(polyline, anchors, min_width);
+        }
+    }
+
     //reduce extrusion when it's too thin to be printable
     remove_too_thin_extrusion(pp);
     //{
@@ -1385,13 +1397,15 @@ MedialAxis::build(ThickPolylines* polylines_out)
 
     // Loop through all returned polylines in order to extend their endpoints to the 
     //   expolygon boundaries
-    const ExPolygons anchors = offset2_ex(to_polygons(diff_ex(this->bounds, this->expolygon)), -SCALED_RESOLUTION, SCALED_RESOLUTION);
-    for (size_t i = 0; i < pp.size(); ++i) {
-        ThickPolyline& polyline = pp[i];
-        extends_line(polyline, anchors, min_width);
-        polyline.reverse();
-        extends_line(polyline, anchors, min_width);
-    }
+    if (!stop_at_min_width) {
+		const ExPolygons anchors = offset2_ex(to_polygons(diff_ex(this->bounds, this->expolygon)), -SCALED_RESOLUTION, SCALED_RESOLUTION);
+		for (size_t i = 0; i < pp.size(); ++i) {
+			ThickPolyline& polyline = pp[i];
+			extends_line(polyline, anchors, min_width);
+			polyline.reverse();
+			extends_line(polyline, anchors, min_width);
+		}
+	}
     //{
     //    stringstream stri;
     //    stri << "medial_axis_5_expand_" << id << ".svg";
diff --git a/xs/src/libslic3r/MedialAxis.hpp b/xs/src/libslic3r/MedialAxis.hpp
index 93f6725db2d..3ec9d467d27 100644
--- a/xs/src/libslic3r/MedialAxis.hpp
+++ b/xs/src/libslic3r/MedialAxis.hpp
@@ -23,6 +23,7 @@ namespace Slic3r {
         const double max_width;
         const double min_width;
         const double height;
+        bool stop_at_min_width = true;
         MedialAxis(const ExPolygon &_expolygon, const ExPolygon &_bounds, const double _max_width, const double _min_width, const double _height)
             : surface(_expolygon), bounds(_bounds), max_width(_max_width), min_width(_min_width), height(_height) {
         };