add slow_down_layers

src/libslic3r/GCode.cpp

@@ -3370,6 +3370,19 @@ std::string GCodeGenerator::_extrude(
             m_config.get_abs_value("first_layer_speed", speed);
     else if (this->object_layer_over_raft())
         speed = m_config.get_abs_value("first_layer_speed_over_raft", speed);
+    //w25
+    else if (m_config.slow_down_layers > 1) {
+        const auto _layer = layer_id() + 1;
+        if (_layer > 0 && _layer < m_config.slow_down_layers) {
+            const auto first_layer_speed = (path_attr.role==ExtrusionRole::Perimeter||path_attr.role==ExtrusionRole::ExternalPerimeter) ? m_config.get_abs_value("first_layer_speed") :
+                                                                       m_config.get_abs_value("first_layer_infill_speed");
+            if (first_layer_speed < speed) {
+                speed = std::min(speed, Slic3r::lerp(first_layer_speed, speed, (double) _layer / m_config.slow_down_layers));
+            }
+        }
+    }
+    
+    
 
     std::pair<float, float> dynamic_speed_and_fan_speed{-1, -1};
     if (path_attr.overhang_attributes.has_value()) {

src/libslic3r/GCode.hpp

@@ -465,6 +465,13 @@ private:
 
     // On the first printing layer. This flag triggers first layer speeds.
     bool                                on_first_layer() const { return m_layer != nullptr && m_layer->id() == 0; }
+    //w25
+    int layer_id() const
+    {
+        if (m_layer == nullptr)
+            return -1;
+        return m_layer->id();
+    }
     // To control print speed of 1st object layer over raft interface.
     bool                                object_layer_over_raft() const { return m_object_layer_over_raft; }
 

src/libslic3r/Preset.cpp

@@ -483,6 +483,8 @@ static std::vector<std::string> s_Preset_print_options {
     ,"filter_top_gap_infill"
     //w23
     ,"only_one_wall_first_layer"
+    //w25
+    ,"slow_down_layers"
 };
 
 static std::vector<std::string> s_Preset_filament_options {

src/libslic3r/Print.cpp

@@ -251,7 +251,9 @@ bool Print::invalidate_state_by_config_options(const ConfigOptionResolver & /* n
             || opt_key == "first_layer_travel_speed"
             //B37
             || opt_key == "first_layer_infill_speed"
-            || opt_key == "z_offset") {
+            || opt_key == "z_offset"
+            //w25
+            || opt_key == "slow_down_layers") {
             steps.emplace_back(psWipeTower);
             steps.emplace_back(psSkirtBrim);
         } else if (opt_key == "filament_soluble") {

src/libslic3r/PrintConfig.cpp

@@ -1482,6 +1482,16 @@ void PrintConfigDef::init_fff_params()
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionFloatOrPercent(30, false));
 
+    //w25
+    def           = this->add("slow_down_layers", coInt);
+    def->label    = L("Number of slow layers");
+    def->tooltip  = L("The first few layers are printed slower than normal. "
+                     "The speed is gradually increased in a linear fashion over the specified number of layers.");
+    def->category = L("Speed");
+    def->min      = 0;
+    def->mode     = comAdvanced;
+    def->set_default_value(new ConfigOptionInt(0));
+
     def = this->add("first_layer_temperature", coInts);
     def->label = L("First layer");
     def->full_label = L("First layer nozzle temperature");

src/libslic3r/PrintConfig.hpp

@@ -857,6 +857,8 @@ PRINT_CONFIG_CLASS_DERIVED_DEFINE(
     ((ConfigOptionFloatOrPercent,     first_layer_extrusion_width))
     ((ConfigOptionFloatOrPercent,     first_layer_height))
     ((ConfigOptionFloatOrPercent,     first_layer_speed))
+    //w25
+    ((ConfigOptionInt,                slow_down_layers))
     ((ConfigOptionInts,               first_layer_temperature))
     ((ConfigOptionIntsNullable,       idle_temperature))
     //B26

src/slic3r/GUI/Tab.cpp

@@ -1607,6 +1607,8 @@ void TabPrint::build()
         optgroup->append_single_option_line("first_layer_travel_speed");
         
         optgroup->append_single_option_line("first_layer_speed_over_raft");
+        //w25
+        optgroup->append_single_option_line("slow_down_layers");
 
         optgroup = page->new_optgroup(L("Acceleration control (advanced)"));
         optgroup->append_single_option_line("external_perimeter_acceleration");