SLA support points improvements

- semi-intelligent algorithm to place support points
- enhanced ImGui dialog with editing/non-editing mode
- support points can have different head diameter (only implemented in GUI so far)
- autogenerated points supporting emerging islands are annotated and the info is kept

src/slic3r/GUI/GLGizmo.hpp

@@ -441,27 +441,16 @@ class GLGizmoSlaSupports : public GLGizmoBase
 {
 private:
     ModelObject* m_model_object = nullptr;
-#if ENABLE_SLA_SUPPORT_GIZMO_MOD
     ModelObject* m_old_model_object = nullptr;
     int m_old_instance_id = -1;
-#else
-    Transform3d m_instance_matrix;
-#endif // ENABLE_SLA_SUPPORT_GIZMO_MOD
     Vec3f unproject_on_mesh(const Vec2d& mouse_pos);
 
-#if ENABLE_SLA_SUPPORT_GIZMO_MOD
     GLUquadricObj* m_quadric;
-#endif // ENABLE_SLA_SUPPORT_GIZMO_MOD
-
     Eigen::MatrixXf m_V; // vertices
     Eigen::MatrixXi m_F; // facets indices
     igl::AABB<Eigen::MatrixXf,3> m_AABB;
 
     struct SourceDataSummary {
-#if !ENABLE_SLA_SUPPORT_GIZMO_MOD
-        BoundingBoxf3 bounding_box;
-        Transform3d matrix;
-#endif // !ENABLE_SLA_SUPPORT_GIZMO_MOD
         Vec3d mesh_first_point;
     };
 
@@ -472,12 +461,8 @@ private:
 
 public:
     explicit GLGizmoSlaSupports(GLCanvas3D& parent);
-#if ENABLE_SLA_SUPPORT_GIZMO_MOD
     virtual ~GLGizmoSlaSupports();
     void set_sla_support_data(ModelObject* model_object, const GLCanvas3D::Selection& selection);
-#else
-    void set_model_object_ptr(ModelObject* model_object);
-#endif // ENABLE_SLA_SUPPORT_GIZMO_MOD
     void clicked_on_object(const Vec2d& mouse_position);
     void delete_current_grabber(bool delete_all);
 
@@ -487,11 +472,7 @@ private:
     virtual void on_render(const GLCanvas3D::Selection& selection) const;
     virtual void on_render_for_picking(const GLCanvas3D::Selection& selection) const;
 
-#if ENABLE_SLA_SUPPORT_GIZMO_MOD
     void render_grabbers(const GLCanvas3D::Selection& selection, bool picking = false) const;
-#else
-    void render_grabbers(bool picking = false) const;
-#endif // ENABLE_SLA_SUPPORT_GIZMO_MOD
     bool is_mesh_update_necessary() const;
     void update_mesh();
 
@@ -501,6 +482,10 @@ private:
     mutable GLTexture m_reset_texture;
 #endif // not ENABLE_IMGUI
 
+    bool m_lock_unique_islands = false;
+    bool m_editing_mode = false;
+    float m_new_point_head_diameter = 0.4f;
+
 protected:
     void on_set_state() override {
         if (m_state == On && is_mesh_update_necessary()) {