add internal trafo for undo stack

xs/src/libslic3r/Model.cpp

@@ -836,9 +836,20 @@ ModelObject::mirror(const Axis &axis)
     this->invalidate_bounding_box();
 }
 
+void ModelObject::reset_undo_trafo()
+{
+    this->trafo_undo_stack = TransformationMatrix::mat_eye();
+}
+
+TransformationMatrix ModelObject::get_undo_trafo() const
+{
+    return this->trafo_undo_stack;
+}
+
 void
 ModelObject::apply_transformation(const TransformationMatrix & trafo)
 {
+    this->trafo_undo_stack.applyLeft(trafo);
     for (ModelVolumePtrs::const_iterator v = this->volumes.begin(); v != this->volumes.end(); ++v) {
         (*v)->apply_transformation(trafo);
     }

xs/src/libslic3r/Model.hpp

@@ -405,6 +405,12 @@ class ModelObject
     /// \param axis Axis enum member
     void mirror(const Axis &axis);
 
+    /// Reset the internal collection of transformations
+    void reset_undo_trafo();
+
+    /// Get the accumulated collection of transformations since its reset
+    TransformationMatrix get_undo_trafo() const;
+
     /// Transform the current ModelObject by a certain ModelInstance attributes.
     /// Inverse transformation is applied to all the ModelInstances, so that the final size/position/rotation of the transformed objects doesn't change.
     /// \param instance ModelInstance the instance used to transform the current ModelObject
@@ -439,6 +445,7 @@ class ModelObject
     /// Print the current info of this ModelObject
     void print_info() const;
 
+
     private:
     Model* model; ///< Parent object, owning this ModelObject.
 
@@ -455,6 +462,9 @@ class ModelObject
     /// Apply transformation to all volumes
     void apply_transformation(const TransformationMatrix & trafo);
 
+    /// Trafo to collect the transformation applied to all volumes over a series of manipulations
+    TransformationMatrix trafo_undo_stack;
+
     /// = Operator overloading
     /// \param other ModelObject the other ModelObject to be copied
     /// \return ModelObject& the current ModelObject to enable operator cascading

xs/xsp/Model.xsp

@@ -233,6 +233,9 @@ ModelMaterial::attributes()
         %code{% THIS->rotate(*origin, *target); %};
     void mirror(Axis axis);
 
+    void reset_undo_trafo();
+    Clone<TransformationMatrix> get_undo_trafo()
+        %code{% RETVAL = THIS->get_undo_trafo(); %};
 
     void transform_by_instance(ModelInstance* instance, bool dont_translate = false)
         %code{% THIS->transform_by_instance(*instance, dont_translate); %};