Add elephant foot compensation over multiple layers

#prusa3d/PrusaSlicer#10976

Co-authored-by: Roberto Mozzicato <bitblasters@gmail.com>

src/libslic3r/Preset.cpp

@@ -742,7 +742,7 @@ static std::vector<std::string> s_Preset_print_options {
     "ooze_prevention", "standby_temperature_delta", "interface_shells", "line_width", "initial_layer_line_width",
     "inner_wall_line_width", "outer_wall_line_width", "sparse_infill_line_width", "internal_solid_infill_line_width",
     "top_surface_line_width", "support_line_width", "infill_wall_overlap", "bridge_flow",
-    "elefant_foot_compensation", "xy_contour_compensation", "xy_hole_compensation", "resolution", "enable_prime_tower",
+    "elefant_foot_compensation", "elefant_foot_compensation_layers", "xy_contour_compensation", "xy_hole_compensation", "resolution", "enable_prime_tower",
     "prime_tower_width", "prime_tower_brim_width", "prime_volume",
     "wipe_tower_no_sparse_layers", "compatible_printers", "compatible_printers_condition", "inherits",
     "flush_into_infill", "flush_into_objects", "flush_into_support",

src/libslic3r/PrintConfig.cpp

@@ -383,6 +383,17 @@ void PrintConfigDef::init_common_params()
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionFloat(0.));
 
+    def           = this->add("elefant_foot_compensation_layers", coInt);
+    def->label    = L("Elephant foot compensation layers");
+    def->category = L("Quality");
+    def->tooltip  = L("The number of layers on which the elephant foot compensation will be active. "
+                       "The first layer will be shrunk by the elephant foot compensation value, then "
+                       "the next layers will be linearly shrunk less, up to the layer indicated by this value.");
+    def->sidetext = L("layers");
+    def->min      = 1;
+    def->mode     = comAdvanced;
+    def->set_default_value(new ConfigOptionInt(1));	
+
     def = this->add("layer_height", coFloat);
     def->label = L("Layer height");
     def->category = L("Quality");

src/libslic3r/PrintConfig.hpp

@@ -643,6 +643,7 @@ PRINT_CONFIG_CLASS_DEFINE(
     ((ConfigOptionFloat,               brim_ears_max_angle))
     ((ConfigOptionBool,                bridge_no_support))
     ((ConfigOptionFloat,               elefant_foot_compensation))
+    ((ConfigOptionInt,                 elefant_foot_compensation_layers))
     ((ConfigOptionFloat,               max_bridge_length))
     ((ConfigOptionFloatOrPercent,      line_width))
     // Force the generation of solid shells between adjacent materials/volumes.

src/libslic3r/PrintObject.cpp

@@ -805,6 +805,7 @@ bool PrintObject::invalidate_state_by_config_options(
             steps.emplace_back(posSlice);
 		} else if (
                opt_key == "elefant_foot_compensation"
+            || opt_key == "elefant_foot_compensation_layers"
             || opt_key == "support_top_z_distance"
             || opt_key == "support_bottom_z_distance"
             || opt_key == "xy_hole_compensation"

src/libslic3r/PrintObjectSlice.cpp

@@ -1085,7 +1085,9 @@ void PrintObject::slice_volumes()
 	                m_print->throw_if_canceled();
 	                Layer *layer = m_layers[layer_id];
 	                // Apply size compensation and perform clipping of multi-part objects.
-	                float elfoot = (layer_id == 0) ? elephant_foot_compensation_scaled : 0.f;
+	                float elfoot = elephant_foot_compensation_scaled > 0 && layer_id < m_config.elefant_foot_compensation_layers.value ? 
+                        elephant_foot_compensation_scaled - (elephant_foot_compensation_scaled / m_config.elefant_foot_compensation_layers.value) * layer_id : 
+                        0.f;
 	                if (layer->m_regions.size() == 1) {
 	                    // Optimized version for a single region layer.
 	                    // Single region, growing or shrinking.

src/slic3r/GUI/Tab.cpp

@@ -1867,6 +1867,7 @@ void TabPrint::build()
         optgroup->append_single_option_line("xy_hole_compensation");
         optgroup->append_single_option_line("xy_contour_compensation");
         optgroup->append_single_option_line("elefant_foot_compensation");
+        optgroup->append_single_option_line("elefant_foot_compensation_layers");
         optgroup->append_single_option_line("precise_outer_wall");
 
         optgroup = page->new_optgroup(L("Ironing"), L"param_ironing");