gap_fill_extension and gap_fill_min_length

resources/ui_layout/default/print.ui

@@ -62,16 +62,18 @@ group:label_width$12:Overhangs
 		setting:sidetext_width$2:overhangs_reverse
 		setting:label_width$12:width$5:overhangs_reverse_threshold
 	end_line
-group:Advanced
+group:sidetext_width$5:Advanced
 	setting:width$25:no_perimeter_unsupported_algo
 	line:Gap Fill
 		setting:label$_:gap_fill_enabled
 		setting:width$5:gap_fill_last
+		setting:width$5:gap_fill_extension
 	end_line
 	line:Gap Fill threshold
 		setting:width$5:gap_fill_min_width
 		setting:width$5:gap_fill_max_width
-		setting:width$5:gap_fill_min_area
+		setting:width$5:sidetext_width$6:gap_fill_min_area
+		setting:width$5:gap_fill_min_length
 	end_line
 	line:Seam
 		setting:tags$Simple$Advanced$Expert$Prusa$SuSi:script:enum$corners$Corners$nearest$Nearest$random$Random$aligned$Aligned$rear$Rear$custom$Custom:depends$seam_position$seam_angle_cost$seam_travel_cost:label$Seam position:label_width$12:sidetext_width$0:tooltip$Position of perimeters' starting points.\nCustom can be defined in Advanced or Expert mode. Cost-based settings let you choose the angle and travel cost. A high angle cost will place the seam where it can be hidden by a corner, the travel cost place the seam near the last position (often at the end of the previous infill).:s_seam_position
@@ -87,7 +89,7 @@ group:Advanced
 	line:Fuzzy skin (experimental)
 		setting:sidetext_width$1:label$_:fuzzy_skin
 		setting:width$6:sidetext_width$6:fuzzy_skin_thickness
-		setting:width$6:sidetext_width$5:fuzzy_skin_point_dist
+		setting:width$6:fuzzy_skin_point_dist
 	end_line
 group:External perimeter first
 	setting:label$Activate:external_perimeters_first

src/libslic3r/Geometry/MedialAxis.cpp

@@ -1596,6 +1596,23 @@ MedialAxis::extends_line(ThickPolyline& polyline, const ExPolygons& anchors, con
     }
 }
 
+void
+MedialAxis::extends_line_extra(ThickPolylines& pp) {
+    // opening : offset2-+
+    for (size_t i = 0; i < pp.size(); ++i) {
+        ThickPolyline& polyline = pp[i];
+
+        if (polyline.endpoints.first) {
+            polyline.extend_start(this->extension_length);
+        }
+        if (polyline.endpoints.second) {
+            polyline.extend_end(this->extension_length);
+        }
+    }
+}
+
+
+
 void
 MedialAxis::main_fusion(ThickPolylines& pp)
 {
@@ -2059,7 +2076,7 @@ MedialAxis::concatenate_small_polylines(ThickPolylines& pp)
     /*
      new goal: ensure that if there is a too short segment, it will be connected with a sufficiently long one, to save it
     */
-    coordf_t shortest_size = (coordf_t)this->min_length;
+    const coordf_t shortest_size = (coordf_t)this->min_length;
     std::set<size_t> deleted;
     std::vector<size_t> idx_per_size;
     //TODO: cache the length
@@ -2425,10 +2442,11 @@ MedialAxis::remove_too_short_polylines(ThickPolylines& pp)
             // know how long will the endpoints be extended since it depends on polygon thickness
             // which is variable - extension will be <= max_width/2 on each side) 
             if ((polyline.endpoints.first || polyline.endpoints.second)) {
-                coordf_t local_max_width = this->max_width / 2;
+                coordf_t local_min_length = this->max_width / 2;
                 for (coordf_t w : polyline.width)
-                    local_max_width = std::max(local_max_width, w);
-                if (polyline.length() < local_max_width) {
+                    local_min_length = std::max(local_min_length, w - SCALED_EPSILON);
+                local_min_length = std::max(local_min_length, shortest_size);
+                if (polyline.length() < local_min_length) {
                     if (shortest_size > polyline.length()) {
                         shortest_size = polyline.length();
                         shortest_idx = i;
@@ -2969,6 +2987,8 @@ MedialAxis::build(ThickPolylines& polylines_out)
     //    svg.Close();
     //}
 
+    extends_line_extra(pp);
+
     remove_too_short_polylines(pp);
     //{
     //    std::stringstream stri;

src/libslic3r/Geometry/MedialAxis.hpp

@@ -73,6 +73,7 @@ class MedialAxis {
     MedialAxis& set_stop_at_min_width(const bool stop_at_min_width) { this->stop_at_min_width = stop_at_min_width; return *this; }
     MedialAxis& set_min_length(const coord_t min_length) { this->min_length = min_length; return *this; }
     MedialAxis& set_biggest_width(const coord_t biggest_width) { this->biggest_width = biggest_width; return *this; }
+    MedialAxis& set_extension_length(const coord_t extension_length) { this->extension_length = extension_length; return *this; }
 
 private:
 
@@ -99,6 +100,8 @@ class MedialAxis {
     coord_t taper_size;
     //if true, remove_too_* can shorten the bits created by extends_line.
     bool stop_at_min_width;
+    // arbitrary extra extension at ends.
+    coord_t extension_length = 0;
 
     //voronoi stuff
     class VD : public voronoi_diagram<double> {

src/libslic3r/Layer.cpp

@@ -183,8 +183,10 @@ void Layer::make_perimeters()
                 && ((config.gap_fill_speed          == other_config.gap_fill_speed) || !config.gap_fill_enabled)
                 && config.gap_fill_last             == other_config.gap_fill_last
                 && config.gap_fill_flow_match_perimeter == other_config.gap_fill_flow_match_perimeter
+                && config.gap_fill_extension         == other_config.gap_fill_extension
                 && config.gap_fill_max_width         == other_config.gap_fill_max_width
                 && config.gap_fill_min_area         == other_config.gap_fill_min_area
+                && config.gap_fill_min_length         == other_config.gap_fill_min_length
                 && config.gap_fill_min_width         == other_config.gap_fill_min_width
                 && config.gap_fill_overlap          == other_config.gap_fill_overlap
                 && config.infill_dense              == other_config.infill_dense

src/libslic3r/PerimeterGenerator.cpp

@@ -1133,13 +1133,15 @@ void PerimeterGenerator::process()
             coordf_t real_max = 2.5 * perimeter_spacing;
             const coordf_t minwidth = scale_d(this->config->gap_fill_min_width.get_abs_value(unscaled((double)perimeter_width)));
             const coordf_t maxwidth = scale_d(this->config->gap_fill_max_width.get_abs_value(unscaled((double)perimeter_width)));
+            const coord_t minlength = scale_t(this->config->gap_fill_min_length.get_abs_value(unscaled((double)perimeter_width)));
             if (minwidth > 0) {
                 min = std::max(min, minwidth);
             }
             coordf_t max = real_max;
             if (maxwidth > 0) {
                 max = std::min(max, maxwidth);
             }
+            const coord_t gapfill_extension = scale_t(this->config->gap_fill_extension.get_abs_value(unscaled((double)perimeter_width)));
             //remove areas that are too big (shouldn't occur...)
             ExPolygons too_big = offset2_ex(gaps, double(-max / 2), double(+max / 2));
             ExPolygons gaps_ex_to_test = too_big.empty() ? gaps : diff_ex(gaps, too_big, ApplySafetyOffset::Yes);
@@ -1198,9 +1200,15 @@ void PerimeterGenerator::process()
             // create lines from the area
             ThickPolylines polylines;
             for (const ExPolygon& ex : gaps_ex) {
-                Geometry::MedialAxis{ ex, coord_t(real_max), coord_t(min), coord_t(this->layer->height) }
-                    .set_biggest_width(max)
-                    .build(polylines);
+                Geometry::MedialAxis md{ ex, coord_t(real_max), coord_t(min), coord_t(this->layer->height) };
+                if (minlength > 0) {
+                    md.set_min_length(minlength);
+                }
+                if (gapfill_extension > 0) {
+                    md.set_extension_length(gapfill_extension);
+                }
+                md.set_biggest_width(max);
+                md.build(polylines);
             }
             // create extrusion from lines
             if (!polylines.empty()) {

src/libslic3r/Preset.cpp

@@ -532,10 +532,12 @@ static std::vector<std::string> s_Preset_print_options {
         "max_volumetric_speed",
         // gapfill
         "gap_fill_enabled",
+        "gap_fill_extension",
         "gap_fill_flow_match_perimeter",
         "gap_fill_last",
         "gap_fill_max_width",
         "gap_fill_min_area",
+        "gap_fill_min_length",
         "gap_fill_min_width",
         "gap_fill_overlap",
         "gap_fill_speed",

src/libslic3r/PrintConfig.cpp

@@ -2585,6 +2585,18 @@ void PrintConfigDef::init_fff_params()
     def->mode = comExpert | comSuSi;
     def->set_default_value(new ConfigOptionFloatOrPercent(0,false));
 
+    def = this->add("gap_fill_extension", coFloatOrPercent);
+    def->label = L("Extension");
+    def->full_label = L("Gapfill: extra extension");
+    def->category = OptionCategory::perimeter;
+    def->tooltip = L("Increase the length of all gapfills by this amount (may overextrude a little bit)\nCan be a % of the perimeter width");
+    def->ratio_over = "perimeter_width";
+    def->sidetext = L("mm or %");
+    def->min = 0;
+    def->max_literal = { 50, true };
+    def->mode = comExpert | comSuSi;
+    def->set_default_value(new ConfigOptionFloatOrPercent{ 0, false });
+
     def = this->add("gap_fill_flow_match_perimeter", coPercent);
     def->label = L("Cap with perimeter flow");
     def->full_label = L("Gapfill: cap speed with perimeter flow");
@@ -2627,6 +2639,17 @@ void PrintConfigDef::init_fff_params()
     def->mode = comExpert | comSuSi;
     def->set_default_value(new ConfigOptionFloatOrPercent{ 100, true });
 
+    def = this->add("gap_fill_min_length", coFloatOrPercent);
+    def->label = L("Min length");
+    def->full_label = L("Gapfill: Min length");
+    def->category = OptionCategory::perimeter;
+    def->tooltip = L("This setting represents the minimum mm for a gapfill extrusion to be extruded.\nCan be a % of the perimeter width\n0 to auto");
+    def->ratio_over = "perimeter_width";
+    def->sidetext = L("mm or %");
+    def->min = 0;
+    def->mode = comExpert | comSuSi;
+    def->set_default_value(new ConfigOptionFloatOrPercent{ 0, false });
+
     def = this->add("gap_fill_min_width", coFloatOrPercent);
     def->label = L("Min width");
     def->full_label = L("Gapfill: Min width");

src/libslic3r/PrintConfig.hpp

@@ -810,10 +810,12 @@ PRINT_CONFIG_CLASS_DEFINE(
     ((ConfigOptionPercent,              fill_smooth_distribution))
     ((ConfigOptionFloatOrPercent,       fill_smooth_width))
     ((ConfigOptionBool,                 gap_fill_enabled))
+    ((ConfigOptionFloatOrPercent,       gap_fill_extension))
     ((ConfigOptionPercent,              gap_fill_flow_match_perimeter))
     ((ConfigOptionBool,                 gap_fill_last))
     ((ConfigOptionFloatOrPercent,       gap_fill_max_width))
     ((ConfigOptionFloatOrPercent,       gap_fill_min_area))
+    ((ConfigOptionFloatOrPercent,       gap_fill_min_length))
     ((ConfigOptionFloatOrPercent,       gap_fill_min_width))
     ((ConfigOptionPercent,              gap_fill_overlap))
     ((ConfigOptionFloatOrPercent,       gap_fill_speed))

src/libslic3r/PrintObject.cpp

@@ -713,9 +713,11 @@ bool PrintObject::invalidate_state_by_config_options(
         for (const t_config_option_key& opt_key : opt_keys) {
             if (
                 opt_key == "gap_fill_enabled"
+                || opt_key == "gap_fill_extension"
                 || opt_key == "gap_fill_last"
                 || opt_key == "gap_fill_max_width"
                 || opt_key == "gap_fill_min_area"
+                || opt_key == "gap_fill_min_length"
                 || opt_key == "gap_fill_min_width"
                 || opt_key == "only_one_perimeter_first_layer"
                 || opt_key == "only_one_perimeter_top"

src/slic3r/GUI/ConfigManipulation.cpp

@@ -345,7 +345,7 @@ void ConfigManipulation::toggle_print_fff_options(DynamicPrintConfig* config)
 
     toggle_field("perimeter_loop_seam", config->opt_bool("perimeter_loop"));
 
-    for (auto el : { "gap_fill_last", "gap_fill_max_width", "gap_fill_min_area", "gap_fill_min_width" })
+    for (auto el : { "gap_fill_extension", "gap_fill_last", "gap_fill_max_width", "gap_fill_min_area", "gap_fill_min_length", "gap_fill_min_width" })
         toggle_field(el, config->opt_bool("gap_fill_enabled"));
 
     for (auto el : { "fuzzy_skin_thickness", "fuzzy_skin_point_dist" })