nearest is now near (Nearest), hidden is now hidden (Corners).

Seam position default to corners (hidden) from "nearest", to avoid confusion when migrating from a prusaslicer config.
fix for modifiers with no_perimeter_unsupported_algo
npuaBridges surface fix

src/libslic3r/Layer.cpp

@@ -138,6 +138,7 @@ void Layer::make_perimeters()
                 && config.gap_fill_speed            == other_config.gap_fill_speed
                 && config.infill_dense              == other_config.infill_dense
                 && config.infill_dense_algo         == other_config.infill_dense_algo
+                && config.no_perimeter_unsupported_algo == other_config.no_perimeter_unsupported_algo
                 && config.only_one_perimeter_top    == other_config.only_one_perimeter_top
                 && config.overhangs                 == other_config.overhangs
                 && config.overhangs_width           == other_config.overhangs_width

src/libslic3r/PerimeterGenerator.cpp

@@ -210,10 +210,12 @@ void PerimeterGenerator::process()
                                         unbridgeable = offset2_ex(unbridgeable, -ext_perimeter_width*2, ext_perimeter_width*2);
                                         ExPolygons bridges_temp = intersection_ex(last, diff_ex(unsupported_filtered, unbridgeable));
                                         //remove the overhangs section form the surface polygons
+                                        ExPolygons reference = last;
                                         last = diff_ex(last, unsupported_filtered);
                                         //ExPolygons no_bridge = diff_ex(offset_ex(unbridgeable, ext_perimeter_width * 3 / 2), last);
                                         //bridges_temp = diff_ex(bridges_temp, no_bridge);
                                         unsupported_filtered = diff_ex(offset_ex(bridges_temp, ext_perimeter_width * 3 / 2), offset_ex(unbridgeable, ext_perimeter_width*2, jtSquare));
+                                        unsupported_filtered = intersection_ex(unsupported_filtered, reference);
                                     } else {
                                         ExPolygons unbridgeable = intersection_ex(unsupported, diff_ex(unsupported_filtered, offset_ex(bridgeable_simplified, ext_perimeter_width / 2)));
                                         unbridgeable = offset2_ex(unbridgeable, -ext_perimeter_width, ext_perimeter_width);

src/libslic3r/PrintConfig.cpp

@@ -2261,7 +2261,7 @@ void PrintConfigDef::init_fff_params()
     def->tooltip = L("Position of perimeters starting points.");
     def->enum_keys_map = &ConfigOptionEnum<SeamPosition>::get_enum_values();
     def->enum_values.push_back("random");
-    def->enum_values.push_back("nearest");
+    def->enum_values.push_back("near");
     def->enum_values.push_back("aligned");
     def->enum_values.push_back("rear");
     def->enum_values.push_back("hidden");
@@ -2269,7 +2269,7 @@ void PrintConfigDef::init_fff_params()
     def->enum_labels.push_back(L("Nearest"));
     def->enum_labels.push_back(L("Aligned"));
     def->enum_labels.push_back(L("Rear"));
-    def->enum_labels.push_back(L("Hidden"));
+    def->enum_labels.push_back(L("Corners"));
     def->mode = comSimple;
     def->set_default_value(new ConfigOptionEnum<SeamPosition>(spHidden));
 

src/libslic3r/PrintConfig.hpp

@@ -191,7 +191,8 @@ template<> inline const t_config_enum_values& ConfigOptionEnum<SeamPosition>::ge
     static t_config_enum_values keys_map;
     if (keys_map.empty()) {
         keys_map["random"]              = spRandom;
-        keys_map["nearest"]             = spNearest;
+        keys_map["nearest"]             = spHidden;
+        keys_map["near"]                = spNearest;
         keys_map["aligned"]             = spAligned;
         keys_map["rear"]                = spRear;
         keys_map["hidden"]              = spHidden;

src/libslic3r/PrintObject.cpp

@@ -1060,7 +1060,7 @@ void PrintObject::detect_surfaces_type()
                     float        offset = layerm->flow(frExternalPerimeter).scaled_width() / 10.f;
 
                     Polygons     layerm_slices_surfaces = to_polygons(layerm->slices().surfaces);
-                    // no_perimeter_full_bridge allow to put bridges where there are nothing, hence adding area to silce, that's why we need to start from the result of PerimeterGenerator.
+                    // no_perimeter_full_bridge allow to put bridges where there are nothing, hence adding area to slice, that's why we need to start from the result of PerimeterGenerator.
                     if (layerm->region()->config().no_perimeter_unsupported_algo == npuaFilled) {
                         layerm_slices_surfaces = union_(layerm_slices_surfaces, to_polygons(layerm->fill_surfaces));
                     }