From b20dfac403042e89bc0c177509107268c017d0cb Mon Sep 17 00:00:00 2001
From: Pavel Mikus <pavel.mikus.mail@seznam.cz>
Date: Fri, 2 Jun 2023 16:20:13 +0200
Subject: [PATCH] update fix of SPE-1685 - make the closing raidus half the
 size, it was unnecesarily large

---
 src/libslic3r/LayerRegion.cpp | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/src/libslic3r/LayerRegion.cpp b/src/libslic3r/LayerRegion.cpp
index f378db2a4..9485998dc 100644
--- a/src/libslic3r/LayerRegion.cpp
+++ b/src/libslic3r/LayerRegion.cpp
@@ -171,7 +171,7 @@ Surfaces expand_bridges_detect_orientations(
     Surfaces                                    &surfaces,
     ExPolygons                                  &shells,
     const Algorithm::RegionExpansionParameters  &expansion_params,
-    const float                                 closing_diameter)
+    const float                                 closing_radius)
 {
     using namespace Slic3r::Algorithm;
 
@@ -314,7 +314,7 @@ Surfaces expand_bridges_detect_orientations(
                 //NOTE: The current regularization of the shells can create small unasigned regions in the object (E.G. benchy)
                 // without the following closing operation, those regions will stay unfilled and cause small holes in the expanded surface.
                 // look for narrow_ensure_vertical_wall_thickness_region_radius filter.
-                ExPolygons final = closing_ex(acc, closing_diameter);
+                ExPolygons final = closing_ex(acc, closing_radius);
                 // without safety offset, artifacts are generated (GH #2494)
                 // union_safety_offset_ex(acc)
                 for (ExPolygon &ex : final)
@@ -334,7 +334,7 @@ static Surfaces expand_merge_surfaces(
     SurfaceType                                 surface_type,
     ExPolygons                                 &shells,
     const Algorithm::RegionExpansionParameters &params,
-    const float                                 closing_diameter,
+    const float                                 closing_radius,
     const double                                bridge_angle = -1.)
 {
     double thickness;
@@ -346,7 +346,7 @@ static Surfaces expand_merge_surfaces(
     //NOTE: The current regularization of the shells can create small unasigned regions in the object (E.G. benchy)
     // without the following closing operation, those regions will stay unfilled and cause small holes in the expanded surface.
     // look for narrow_ensure_vertical_wall_thickness_region_radius filter.
-    expanded = closing_ex(expanded, closing_diameter);
+    expanded = closing_ex(expanded, closing_radius);
     // Trim the shells by the expanded expolygons.
     shells = diff_ex(shells, expanded);
 
@@ -385,7 +385,8 @@ void LayerRegion::process_external_surfaces(const Layer *lower_layer, const Poly
     static constexpr const float    expansion_step          = scaled<float>(0.1);
     // Don't take more than max_nr_steps for small expansion_step.
     static constexpr const size_t   max_nr_expansion_steps  = 5;
-    const float closing_diameter = 0.65f * 1.05 * this->flow(frSolidInfill).scaled_spacing();
+    // Radius (with added epsilon) to absorb empty regions emering from regularization of ensuring, viz  const float narrow_ensure_vertical_wall_thickness_region_radius = 0.5f * 0.65f * min_perimeter_infill_spacing;
+    const float closing_radius = 0.55f * 0.65f * 1.05f * this->flow(frSolidInfill).scaled_spacing();
 
     // Expand the top / bottom / bridge surfaces into the shell thickness solid infills.
     double     layer_thickness;
@@ -397,8 +398,8 @@ void LayerRegion::process_external_surfaces(const Layer *lower_layer, const Poly
         const double custom_angle = this->region().config().bridge_angle.value;
         const auto   params = Algorithm::RegionExpansionParameters::build(expansion_bottom_bridge, expansion_step, max_nr_expansion_steps);
         bridges.surfaces = custom_angle > 0 ?
-            expand_merge_surfaces(m_fill_surfaces.surfaces, stBottomBridge, shells, params, closing_diameter, Geometry::deg2rad(custom_angle)) :
-            expand_bridges_detect_orientations(m_fill_surfaces.surfaces, shells, params, closing_diameter);
+            expand_merge_surfaces(m_fill_surfaces.surfaces, stBottomBridge, shells, params, closing_radius, Geometry::deg2rad(custom_angle)) :
+            expand_bridges_detect_orientations(m_fill_surfaces.surfaces, shells, params, closing_radius);
         BOOST_LOG_TRIVIAL(trace) << "Processing external surface, detecting bridges - done";
 #if 0
         {
@@ -409,9 +410,9 @@ void LayerRegion::process_external_surfaces(const Layer *lower_layer, const Poly
     }
 
     Surfaces    bottoms = expand_merge_surfaces(m_fill_surfaces.surfaces, stBottom, shells,
-        Algorithm::RegionExpansionParameters::build(expansion_bottom, expansion_step, max_nr_expansion_steps), closing_diameter);
+        Algorithm::RegionExpansionParameters::build(expansion_bottom, expansion_step, max_nr_expansion_steps), closing_radius);
     Surfaces    tops    = expand_merge_surfaces(m_fill_surfaces.surfaces, stTop, shells,
-        Algorithm::RegionExpansionParameters::build(expansion_top, expansion_step, max_nr_expansion_steps), closing_diameter);
+        Algorithm::RegionExpansionParameters::build(expansion_top, expansion_step, max_nr_expansion_steps), closing_radius);
 
     m_fill_surfaces.remove_types({ stBottomBridge, stBottom, stTop, stInternalSolid });
     reserve_more(m_fill_surfaces.surfaces, shells.size() + bridges.size() + bottoms.size() + tops.size());