FIX: add get_used_extruders interface

Change-Id: I03f0dca933c0aa9de893bc86b268ea727eeee9fb
Signed-off-by: Stone Li <stone.li@bambulab.com>

src/slic3r/GUI/PartPlate.cpp

@@ -1198,6 +1198,28 @@ std::vector<int> PartPlate::get_extruders() const
 	return plate_extruders;
 }
 
+std::vector<int> PartPlate::get_used_extruders()
+{
+	std::vector<int> used_extruders;
+	// if gcode.3mf file
+	if (m_model->objects.empty()) {
+		for (int i = 0; i < slice_filaments_info.size(); i++) {
+			used_extruders.push_back(slice_filaments_info[i].id + 1);
+		}
+		return used_extruders;
+	}
+
+	GCodeProcessorResult* result = get_slice_result();
+	if (!result)
+		return used_extruders;
+
+	PrintEstimatedStatistics& ps = result->print_statistics;
+	for (auto it = ps.volumes_per_extruder.begin(); it != ps.volumes_per_extruder.end(); it++) {
+		used_extruders.push_back(it->first + 1);
+	}
+	return used_extruders;
+}
+
 Vec3d PartPlate::estimate_wipe_tower_size(const double w, const double wipe_volume) const
 {
 	Vec3d wipe_tower_size;

src/slic3r/GUI/PartPlate.hpp

@@ -259,6 +259,7 @@ public:
     Vec3d get_origin() { return m_origin; }
     Vec3d estimate_wipe_tower_size(const double w, const double wipe_volume) const;
     std::vector<int> get_extruders() const;
+    std::vector<int> get_used_extruders();
 
     /* instance related operations*/
     //judge whether instance is bound in plate or not

src/slic3r/GUI/SelectMachine.cpp

@@ -2930,7 +2930,7 @@ void SelectMachineDialog::set_default()
     }
 
     // material info
-    auto        extruders = wxGetApp().plater()->get_partplate_list().get_curr_plate()->get_extruders();
+    auto        extruders = wxGetApp().plater()->get_partplate_list().get_curr_plate()->get_used_extruders();
     BitmapCache bmcache;
 
     MaterialHash::iterator iter = m_materialList.begin();