Prealignment: shift all relevant histograms by 1/2 pitch

(cherry picked from commit 4256f201)

src/modules/Prealignment/Prealignment.cpp

@@ -49,20 +49,20 @@ void Prealignment::initialise() {
     correlationX2Dlocal = new TH2F("correlationX_2Dlocal",
                                    title.c_str(),
                                    m_detector->nPixels().X(),
-                                   0,
-                                   m_detector->nPixels().X(),
+                                   -0.5,
+                                   m_detector->nPixels().X() - 0.5,
                                    reference->nPixels().X(),
-                                   0,
-                                   reference->nPixels().X());
+                                   -0.5,
+                                   reference->nPixels().X() - 0.5);
     title = m_detector->name() + ": 2D correlation Y (local);y [px];y_{ref} [px];events";
     correlationY2Dlocal = new TH2F("correlationY_2Dlocal",
                                    title.c_str(),
                                    m_detector->nPixels().Y(),
-                                   0,
-                                   m_detector->nPixels().Y(),
+                                   -0.5,
+                                   m_detector->nPixels().Y() - 0.5,
                                    reference->nPixels().Y(),
-                                   0,
-                                   reference->nPixels().Y());
+                                   -0.5,
+                                   reference->nPixels().Y() - 0.5);
     title = m_detector->name() + ": 2D correlation X (global);x [mm];x_{ref} [mm];events";
     correlationX2D = new TH2F("correlationX_2D", title.c_str(), 100, -10., 10., 100, -10., 10.);
     title = m_detector->name() + ": 2D correlation Y (global);y [mm];y_{ref} [mm];events";