Save "color_change" for a selected extruder to G_code

src/libslic3r/GCode.cpp

@@ -1685,8 +1685,11 @@ void GCode::process_layer(
     //     colorprint_change = true;
     // } 
     std::string custom_code = "";
+    int m600_before_extruder = -1;
     while (!m_custom_g_code_heights.empty() && m_custom_g_code_heights.front().height-EPSILON < layer.print_z) {
         custom_code = m_custom_g_code_heights.front().gcode;
+        if (custom_code == "M600" && m_custom_g_code_heights.front().extruder > 0)
+            m600_before_extruder = m_custom_g_code_heights.front().extruder - 1;
         m_custom_g_code_heights.erase(m_custom_g_code_heights.begin());
         colorprint_change = true;
     }
@@ -1711,8 +1714,17 @@ void GCode::process_layer(
             // add tag for time estimator
             gcode += "; " + GCodeTimeEstimator::Color_Change_Tag + "\n";
             if (single_material_print && custom_code == "tool_change")
-                custom_code = "M600"; 
-            gcode += custom_code + "\n";
+                custom_code = "M600";
+
+            if (!single_material_print && custom_code == "M600" && 
+                m600_before_extruder >= 0 && first_extruder_id != m600_before_extruder
+                // && !MMU1
+                ) {
+                gcode += "M601\n"; // pause print
+                gcode += "M117 Change filament for Extruder " + std::to_string(m600_before_extruder) + "\n";
+            }
+            else 
+                gcode += custom_code + "\n";
         }
     }
 

src/libslic3r/Model.hpp

@@ -768,7 +768,8 @@ public:
         
         double      height;
         std::string gcode;
-        int         extruder;
+        int         extruder;   // 0    - "gcode" will be applied for whole print
+                                // else - "gcode" will be applied only for "extruder" print
     };
     std::vector<CustomGCode> custom_gcode_per_height;
     

src/slic3r/GUI/GUI_Preview.cpp

@@ -622,9 +622,7 @@ void Preview::create_double_slider()
     m_extruder_selector->Bind(wxEVT_COMBOBOX, [this](wxCommandEvent& evt)
     {
         m_selected_extruder = m_extruder_selector->GetSelection();
-        m_slider->SetManipulationState(m_selected_extruder == 0 ? 
-                                       DoubleSlider::msMultiExtruderWholePrint :
-                                       DoubleSlider::msMultiExtruder);
+        m_slider->SetExtruderID(m_selected_extruder);
 
         int type = m_choice_view_type->FindString(_(L("Color Print")));
 
@@ -767,11 +765,10 @@ void Preview::update_double_slider(const std::vector<double>& layers_z, bool kee
     m_slider->EnableTickManipulation(color_print_enable);
     if (color_print_enable && wxGetApp().extruders_edited_cnt() > 1) {
         //bool is_detected_full_print = //wxGetApp().plater()->fff_print().extruders().size() == 1;
-        m_slider->SetManipulationState(m_extruder_selector->GetSelection()==0 ?
-                                       DoubleSlider::msMultiExtruderWholePrint : DoubleSlider::msMultiExtruder);
+        m_slider->SetExtruderID(m_extruder_selector->GetSelection());
     }
     else
-        m_slider->SetManipulationState(DoubleSlider::msSingleExtruder);
+        m_slider->SetExtruderID(-1);
 
 }
 //  #ys_FIXME_COLOR

src/slic3r/GUI/wxExtensions.cpp

@@ -3461,11 +3461,12 @@ void DoubleSlider::OnRightUp(wxMouseEvent& event)
                 menu.AppendSubMenu(change_extruder_menu, name, _(L("Use another extruder")));
             }
         }
-        else
-            append_menu_item(&menu, wxID_ANY, _(L("Add color change")) + " (M600)", "",
+        
+        append_menu_item(&menu, wxID_ANY, _(L("Add color change")) + " (M600)", "",
             [this](wxCommandEvent&) { add_code("M600"); }, "colorchange_add_off.png", &menu);
-    
-        append_menu_item(&menu, wxID_ANY, _(L("Add pause SD print")) + " (M601)", "",
+
+        if (m_state != msMultiExtruder) 
+        append_menu_item(&menu, wxID_ANY, _(L("Add pause print")) + " (M601)", "",
             [this](wxCommandEvent&) { add_code("M601"); }, "pause_add.png", &menu);
     
         append_menu_item(&menu, wxID_ANY, _(L("Add custom G-code")), "",
@@ -3503,8 +3504,10 @@ void DoubleSlider::add_code(std::string code)
         }
 
         int extruder = 0;
-        if (m_state == msMultiExtruderWholePrint)
+        if (m_state == msMultiExtruderWholePrint && m_custom_gcode != "M600" )
             extruder = get_extruder_for_tick(m_selection == ssLower ? m_lower_value : m_higher_value);
+        else if (m_state == msMultiExtruder && m_current_extruder > 0)
+            extruder = m_current_extruder;
 
         m_ticks_.insert(TICK_CODE(tick, code, extruder));
 

src/slic3r/GUI/wxExtensions.hpp

@@ -828,6 +828,11 @@ public:
         m_state = state;
     }
     ManipulationState GetManipulationState() const { return m_state; }
+    void SetExtruderID(int extruder) {
+        m_current_extruder = extruder;
+        m_state = extruder < 0 ? msSingleExtruder :
+                  extruder > 0 ? msMultiExtruder  : msMultiExtruderWholePrint;
+    }
 
     bool is_horizontal() const { return m_style == wxSL_HORIZONTAL; }
     bool is_one_layer() const { return m_is_one_layer; }
@@ -919,6 +924,7 @@ private:
     bool        m_show_context_menu = false;
     ManipulationState m_state = msSingleExtruder;
     wxString    m_custom_gcode = wxEmptyString;
+    int         m_current_extruder = -1;
 
     wxRect      m_rect_lower_thumb;
     wxRect      m_rect_higher_thumb;