Fix aligned seam & add some others:

 - contiguous: even more aligned
 - scattered: old random: random per island per layer
 - random : new random: every loop has its own random seam.

resources/ui_layout/default/print.as

@@ -156,6 +156,10 @@ void s_not_thick_bridge_set(bool set)
 //    spRandom [spNearest] spAligned spRear [spCustom] spCost
 // ("Cost-based") ("Random") ("Aligned") ("Rear")
 // -> Corners Nearest Random Aligned Rear Custom
+
+//    spRandom spAllRandom [spNearest] spAligned spExtrAligned spRear [spCustom] spCost
+// ("Cost-based") ("Scattered") ("Random") ("Aligned") ("Contiguous") ("Rear")
+// -> Corners Nearest Scattered Random  Aligned Contiguous Rear Custom
 float user_angle = 0;
 float user_travel = 0;
 
@@ -164,8 +168,9 @@ int s_seam_position_get(string &out get_val)
 	int pos = get_int("seam_position");
 	string seam_pos;
 	get_string("seam_position", seam_pos);
-	if(pos < 5){
-		if (pos == 0) return 2;
+	if(pos < 7){
+		if (pos == 0) return 2;// Scattered
+		if (pos == 1) return 3;// Random
 		return pos + 1;
 	} else {
 		float angle = get_float("seam_angle_cost");
@@ -175,26 +180,32 @@ int s_seam_position_get(string &out get_val)
 		user_angle = angle;
 		user_travel = travel;
 	}
-	return 5;
+	return 7;
 }
 
 void s_seam_position_set(string &in set_val, int idx)
 {
 	if (idx == 2 ) {
-		set_int("seam_position", 0);
+		set_int("seam_position", 0); // Scattered
+	} else if (idx == 3) {
+		set_int("seam_position", 1); // Random
+	} else if (idx == 4) {
+		set_int("seam_position", 3); // Aligned
+	} else if (idx == 5) {
+		set_int("seam_position", 4); // Contiguous
+	} else if (idx == 6) {
+		set_int("seam_position", 5); // Rear
 	} else if (idx <= 1) {
-		set_int("seam_position", 5);
+		set_int("seam_position", 7);
 		if (idx == 0) {
 			set_percent("seam_angle_cost", 80);
 			set_percent("seam_travel_cost", 20);
 		} else {
 			set_percent("seam_angle_cost", 30);
 			set_percent("seam_travel_cost", 60);
 		}
-	} else if (idx < 5) {
-		set_int("seam_position", idx - 1);
 	} else {
-		set_int("seam_position", 5);
+		set_int("seam_position", 7);
 		if(user_angle > 0 || user_travel > 0){
 			set_percent("seam_angle_cost", user_angle);
 			set_percent("seam_travel_cost", user_travel);

resources/ui_layout/default/print.ui

@@ -76,7 +76,7 @@ group:sidetext_width$5:Advanced
 		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
+		setting:tags$Simple$Advanced$Expert$Prusa$SuSi:script:enum$corners$Corners$nearest$Nearest$random$Scattered$allrandom$Random$aligned$Aligned$contiguous$Contiguous$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
 #		setting:tags$Expert:label_width$12:sidetext_width$0:seam_position
 		setting:tags$Advanced$Expert$SuSi:width$3:sidetext_width$0:seam_angle_cost
 		setting:tags$Advanced$Expert$SuSi:width$3:sidetext_width$0:seam_travel_cost

src/libslic3r/GCode.cpp

@@ -3685,12 +3685,13 @@ void GCode::split_at_seam_pos(ExtrusionLoop& loop, std::unique_ptr<EdgeGrid::Gri
         if (!loop.split_at_vertex(seam))
             // The point is not in the original loop. Insert it.
             loop.split_at(seam, true);*/
-    } else
-        m_seam_placer.place_seam(loop,
+    } else {
+        m_seam_placer.place_seam(loop, *this->layer(),
             this->last_pos(), m_config.external_perimeters_first,
             EXTRUDER_CONFIG_WITH_DEFAULT(nozzle_diameter, 0.4),
             m_print_object_instance_id,
             lower_layer_edge_grid ? lower_layer_edge_grid->get() : nullptr);
+    }
 }
 
 namespace check_wipe {

src/libslic3r/GCode/SeamPlacer.hpp

@@ -21,9 +21,9 @@ namespace EdgeGrid { class Grid; }
 
 class SeamHistory {
 public:
-    SeamHistory() { clear(); }
-    std::optional<Point> get_last_seam(const PrintObject* po, coord_t layer_z, const BoundingBox& island_bb);
-    void add_seam(const PrintObject* po, const Point& pos, const BoundingBox& island_bb);
+    SeamHistory() {}
+    std::optional<Point> get_last_seam(const PrintObject* po, double layer_z, const BoundingBox& island_bb);
+    void add_seam(const PrintObject* po, const Point& pos, double layer_z, const BoundingBox& island_bb);
     void clear();
 
 private:
@@ -32,8 +32,7 @@ class SeamHistory {
         BoundingBox m_island_bb;
     };
 
-    std::map<const PrintObject*, std::vector<SeamPoint>> m_data_last_layer;
-    std::map<const PrintObject*, std::vector<SeamPoint>> m_data_this_layer;
+    std::vector<std::pair<double, std::map<const PrintObject*, std::vector<SeamPoint>>>> m_data;
     coord_t m_layer_z;
 };
 
@@ -54,7 +53,7 @@ class SeamPlacer {
         const uint16_t print_object_instance_idx,
         const EdgeGrid::Grid* lower_layer_edge_grid);
 
-    void place_seam(ExtrusionLoop& loop, const Point& last_pos, bool external_first, double nozzle_diameter,
+    void place_seam(ExtrusionLoop& loop, const Layer& layer, const Point& last_pos, bool external_first, double nozzle_diameter,
                     const uint16_t print_object_instance_idx, const EdgeGrid::Grid* lower_layer_edge_grid);
 
 

src/libslic3r/PerimeterGenerator.cpp

@@ -2770,7 +2770,7 @@ PerimeterGenerator::_get_nearest_point(const PerimeterGeneratorLoops &children,
             if (myPolylines.paths[idx_poly].length() < dist_cut + perimeter_flow.scaled_width()/20) continue;
 
             if ((myPolylines.paths[idx_poly].role() == erExternalPerimeter || child.is_external() )
-                && this->object_config->seam_position.value != SeamPosition::spRandom) {
+                && (this->object_config->seam_position.value != SeamPosition::spRandom && this->object_config->seam_position.value != SeamPosition::spAllRandom)) {
                 //first, try to find 2 point near enough
                 for (size_t idx_point = 0; idx_point < myPolylines.paths[idx_poly].polyline.points.size(); idx_point++) {
                     const Point &p = myPolylines.paths[idx_poly].polyline.points[idx_point];

src/libslic3r/PrintConfig.cpp

@@ -203,9 +203,11 @@ CONFIG_OPTION_ENUM_DEFINE_STATIC_MAPS(SupportMaterialInterfacePattern)
 
 static const t_config_enum_values s_keys_map_SeamPosition{
         {"random", spRandom},
+        {"allrandom", spAllRandom},
         {"nearest", spNearest}, // unused, replaced by cost
         {"cost", spCost},
         {"aligned", spAligned},
+        {"contiguous", spExtremlyAligned},
         {"rear", spRear},
         {"custom", spCustom}, // for seam object
 };
@@ -4416,11 +4418,15 @@ void PrintConfigDef::init_fff_params()
     def->enum_keys_map = &ConfigOptionEnum<SeamPosition>::get_enum_values();
     def->enum_values.push_back("cost");
     def->enum_values.push_back("random");
+    def->enum_values.push_back("allrandom");
     def->enum_values.push_back("aligned");
+    def->enum_values.push_back("contiguous");
     def->enum_values.push_back("rear");
     def->enum_labels.push_back(L("Cost-based"));
+    def->enum_labels.push_back(L("Scattered"));
     def->enum_labels.push_back(L("Random"));
     def->enum_labels.push_back(L("Aligned"));
+    def->enum_labels.push_back(L("Contiguous"));
     def->enum_labels.push_back(L("Rear"));
     def->mode = comSimpleAE | comPrusa;
     def->set_default_value(new ConfigOptionEnum<SeamPosition>(spCost));

src/libslic3r/PrintConfig.hpp

@@ -166,8 +166,10 @@ enum SupportMaterialInterfacePattern {
 
 enum SeamPosition {
     spRandom,
+    spAllRandom,
     spNearest, //not used anymore
     spAligned,
+    spExtremlyAligned,
     spRear,
     spCustom, // or seam object
     spCost,