RE 7248_MantidEV_show_distance_between_last_points_picked

Initial version, works if Q is in sample coordinates for
both Q and HKL.  In order for this to work for HKL when
Q is in lab coordinates we will need to get and apply
the goniometer rotation.

refs #7248

Code/Mantid/MantidQt/CustomInterfaces/inc/MantidQtCustomInterfaces/MantidEV.h

@@ -396,6 +396,9 @@ private slots:
   std::string  last_ini_file;  /// filename of last settings file that was
                                /// loaded or saved, if any. 
 
+  Mantid::Kernel::V3D last_Q;  /// the last_Q vector that was received from
+                               /// the SelectionNotificationService
+
   QThreadPool  *m_thread_pool; /// local thread pool with only one thread to 
                                /// allow running precisely one operation 
                                /// at a time in a separate thread.

Code/Mantid/MantidQt/CustomInterfaces/inc/MantidQtCustomInterfaces/MantidEVWorker.h

@@ -164,6 +164,10 @@ class DLLExport MantidEVWorker
   /// Display UB and lattice parameters in MantidPlot
   bool showUB( const std::string & peaks_ws_name );
 
+  /// Get the current UB matrix from the peaks workspace
+  bool getUB( const std::string & peaks_ws_name,
+                    Mantid::Kernel::Matrix<double> & UB );
+
   /// Get Info about a Q-Vector from a PeaksWorkspace
   std::vector< std::pair< std::string, std::string > >
                                PointInfo( const std::string & peaks_ws_name, 

Code/Mantid/MantidQt/CustomInterfaces/src/MantidEV.cpp

@@ -189,6 +189,7 @@ void RunEllipsoidIntegrate::run()
  */
 MantidEV::MantidEV(QWidget *parent) : UserSubWindow(parent)
 {
+  last_Q        = V3D(0,0,0);
   worker        = new MantidEVWorker();
   m_thread_pool = new QThreadPool( this );
   m_thread_pool->setMaxThreadCount(1);
@@ -1121,7 +1122,7 @@ void MantidEV::QPointSelection_slot( bool lab_coords, double qx, double qy, doub
  *
  *  @param  lab_coords  Will be true if the Q-components are in lab coordinates
  *                      and false if they are in sample coordinates.
- *  @param q_point Vector containing the Q-coordinates.
+ *  @param  q_point     Vector containing the Q-coordinates.
  */
 void MantidEV::showInfo( bool lab_coords, Mantid::Kernel::V3D  q_point )
 {
@@ -1148,6 +1149,26 @@ void MantidEV::showInfo( bool lab_coords, Mantid::Kernel::V3D  q_point )
      info = worker->PointInfo( peaks_ws_name, lab_coords, q_point );
    }
 
+   double q_dist = ( q_point - last_Q ).norm();
+   std::pair<std::string, std::string> Q_dist_str("|Q2-Q1|", boost::lexical_cast<std::string>(q_dist));
+   info.push_back( Q_dist_str );
+
+   Mantid::Kernel::Matrix<double> UB(3,3,false);
+   if ( worker->getUB( peaks_ws_name, UB ) )      // if the peaks workspace has a UB, also find the
+   {                                              // distance between points in HKL.
+     Mantid::Kernel::Matrix<double> UBinv( UB ); 
+     UBinv.Invert();
+     Mantid::Kernel::V3D  hkl_1 = UBinv * last_Q;
+     Mantid::Kernel::V3D  hkl_2 = UBinv * q_point;
+     hkl_1 = hkl_1 / (2 * M_PI); 
+     hkl_2 = hkl_2 / (2 * M_PI);
+     double hkl_dist = (hkl_2 - hkl_1).norm();
+     std::pair<std::string, std::string> hkl_dist_str("|hkl2-hkl1|", boost::lexical_cast<std::string>(hkl_dist));
+     info.push_back( hkl_dist_str );
+   }
+
+   last_Q = q_point;
+
    m_uiForm.SelectedPoint_tbl->setRowCount((int)info.size());
    m_uiForm.SelectedPoint_tbl->setColumnCount(2);
    m_uiForm.SelectedPoint_tbl->verticalHeader()->hide();

Code/Mantid/MantidQt/CustomInterfaces/src/MantidEVWorker.cpp

@@ -942,6 +942,42 @@ bool MantidEVWorker::showUB( const std::string & peaks_ws_name )
 }
 
 
+/**
+ *  Get the current UB matrix from the specified peaks workspace.
+ *
+ *  @param peaks_ws_name  The name of the peaks workspace with the UB
+ *                        matrix.
+ *  @param UB             3x3 matrix of doubles to be filled out with
+ *                        the UB matrix if one exists in the specified
+ *                        peaks workspace.
+ *  @return true if the UB matrix was found and returned in the UB
+ *               parameter.
+ */
+bool MantidEVWorker::getUB( const std::string & peaks_ws_name,
+                                  Mantid::Kernel::Matrix<double> & UB )
+{
+  if ( !isPeaksWorkspace( peaks_ws_name ) )
+  {
+    return false;
+  }
+
+  const auto& ADS = AnalysisDataService::Instance();
+  IPeaksWorkspace_sptr peaks_ws = ADS.retrieveWS<IPeaksWorkspace>(peaks_ws_name);
+
+  try
+  {
+    Mantid::Geometry::OrientedLattice o_lattice = peaks_ws->mutableSample().getOrientedLattice();
+    UB = o_lattice.getUB();
+  }
+  catch(...)
+  {
+    return false;
+  }
+
+  return true;
+}
+
+
 /**
  * Get information about a specified Q-position from the specified peaks
  * workspace.