#248 add min width for 'only one perimeter'.

resources/ui_layout/print.ui

@@ -16,7 +16,10 @@ group:Horizontal shells
 	top_bottom_shell_thickness_explanation
 	setting:enforce_full_fill_volume
 group:Quality
-	setting:only_one_perimeter_top
+	line:Only one perimeter on Top surfaces
+		setting:label$ :only_one_perimeter_top
+		setting:label$Minimum width:min_width_top_surface
+	end_line
 	line:Extra perimeters
 		setting:extra_perimeters_overhangs
 		setting:extra_perimeters_odd_layers

src/libslic3r/PerimeterGenerator.cpp

@@ -483,6 +483,9 @@ void PerimeterGenerator::process()
                         // it's a bit like re-add thin area in to perimeter area.
                         // it can over-extrude a bit, but it's for a better good.
                         {
+
+
+
                             if(config->thin_perimeters)
                                 next_onion = union_ex(next_onion, offset_ex(diff_ex(last, thins, true),
                                     -(float)(ext_perimeter_width / 2)));
@@ -578,15 +581,18 @@ void PerimeterGenerator::process()
                     if (offset_top_surface > 0.9 * (config->perimeters <= 1 ? 0. : (perimeter_spacing * (config->perimeters - 1))))
                         offset_top_surface -= 0.9 * (config->perimeters <= 1 ? 0. : (perimeter_spacing * (config->perimeters - 1)));
                     else offset_top_surface = 0;
+                    //don't takes into account too thin areas
+                    ExPolygons grown_upper_slices = this->config->min_width_top_surface.value == 0 ? *this->upper_slices :
+                        offset_ex(*this->upper_slices, this->config->min_width_top_surface.get_abs_value(perimeter_width));
                     // get the real top surface
-                    ExPolygons top_polygons = (!have_to_grow_for_miller) ? diff_ex(last, *this->upper_slices, true)
+                    ExPolygons top_polygons = (!have_to_grow_for_miller) ? diff_ex(last, grown_upper_slices, true)
                         :(unmillable.empty())?
-                            diff_ex(last, offset_ex(*this->upper_slices, mill_extra_size), true)
+                            diff_ex(last, offset_ex(grown_upper_slices, mill_extra_size), true)
                                 :
-                        diff_ex(last, diff_ex(offset_ex(*this->upper_slices, mill_extra_size), unmillable, true));
+                        diff_ex(last, diff_ex(offset_ex(grown_upper_slices, mill_extra_size), unmillable, true));
                     
-                    //get the not-top surface, from the "real top" but enlarged by external_infill_margin
+                    //get the not-top surface, from the "real top" but enlarged by external_infill_margin (and the min_width_top_surface we removed a bit before)
-                    ExPolygons inner_polygons = diff_ex(last, offset_ex(top_polygons, offset_top_surface), true);
+                    ExPolygons inner_polygons = diff_ex(last, offset_ex(top_polygons, offset_top_surface + this->config->min_width_top_surface.get_abs_value(perimeter_width)), true);
                     // get the enlarged top surface, by using inner_polygons instead of upper_slices
                     top_polygons = diff_ex(last, inner_polygons, true);
                     // increase by half peri the inner space to fill the frontier between last and stored.

src/libslic3r/PrintConfig.cpp

@@ -2008,6 +2008,18 @@ void PrintConfigDef::init_fff_params()
     def->mode = comSimple;
     def->set_default_value(new ConfigOptionFloats { 0.07 });
 
+    def = this->add("min_width_top_surface", coFloatOrPercent);
+    def->label = L("minimum top width for infill");
+    def->category = OptionCategory::speed;
+    def->tooltip = L("If a top surface has to be printed and it's partially covered by an other layer, it won't be considered at a top layer where his width is below this value."
+        " This can be useful to not let the 'one perimeter on top' trigger on surface that should be covered only by periemters."
+        " This value can be a mm or a % of the perimeter extrusion width.");
+    def->sidetext = L("mm or %");
+    def->ratio_over = "perimeter_extrusion_width";
+    def->min = 0;
+    def->mode = comExpert;
+    def->set_default_value(new ConfigOptionFloatOrPercent(100, true));
+
     def = this->add("min_print_speed", coFloats);
     def->label = L("Min print speed");
     def->category = OptionCategory::speed;
@@ -2015,7 +2027,7 @@ void PrintConfigDef::init_fff_params()
     def->sidetext = L("mm/s");
     def->min = 0;
     def->mode = comExpert;
-    def->set_default_value(new ConfigOptionFloats { 10. });
+    def->set_default_value(new ConfigOptionFloats{ 10. });
 
     def = this->add("min_skirt_length", coFloat);
     def->label = L("Minimal filament extrusion length");

src/libslic3r/PrintConfig.hpp

@@ -654,6 +654,7 @@ public:
     ConfigOptionFloatOrPercent      milling_extra_size;
     ConfigOptionBool                milling_post_process;
     ConfigOptionFloat               milling_speed;
+    ConfigOptionFloatOrPercent      min_width_top_surface;
     // Detect bridging perimeters
     ConfigOptionBool                overhangs;
     ConfigOptionFloatOrPercent      overhangs_width;
@@ -741,6 +742,7 @@ protected:
         OPT_PTR(milling_extra_size);
         OPT_PTR(milling_post_process);
         OPT_PTR(milling_speed);
+        OPT_PTR(min_width_top_surface);
         OPT_PTR(overhangs);
         OPT_PTR(overhangs_width);
         OPT_PTR(overhangs_reverse);

src/slic3r/GUI/ConfigManipulation.cpp

@@ -303,6 +303,7 @@ void ConfigManipulation::toggle_print_fff_options(DynamicPrintConfig* config)
 
     toggle_field("overhangs_width", config->opt_bool("overhangs"));
     toggle_field("overhangs_reverse_threshold", config->opt_bool("overhangs_reverse"));
+    toggle_field("min_width_top_surface", config->opt_bool("only_one_perimeter_top"));
 
     for (auto el : { "external_perimeters_vase", "external_perimeters_nothole", "external_perimeters_hole"})
         toggle_field(el, config->opt_bool("external_perimeters_first"));

src/slic3r/GUI/Preset.cpp

@@ -462,6 +462,7 @@ const std::vector<std::string>& Preset::print_options()
 #ifdef HAS_PRESSURE_EQUALIZER
         "max_volumetric_extrusion_rate_slope_positive", "max_volumetric_extrusion_rate_slope_negative", 
 #endif /* HAS_PRESSURE_EQUALIZER */
+        "min_width_top_surface",
         "perimeter_speed", "small_perimeter_speed", "external_perimeter_speed", "infill_speed", "solid_infill_speed", 
         "top_solid_infill_speed", "support_material_speed", "support_material_xy_spacing", "support_material_interface_speed",
         "bridge_speed",