title: how to make the picked point in point cloud bigger/bold
body: <p>I wanted to make a PCL Visualiser where a user can see co-ordinates of the point in the point cloud when he clicks on it. I implemented that part but now the issue is the user do not get any response which point he picked so I want to make the picked point bigger or if possible coloured.</p>
  
  <p>I am using PCLVisualizer and PointPickingEvent header files provided by PointCloudLibrary.</p>
  
  <pre><code>    void pointPickingOccured( const pcl::visualization::PointPickingEvent &amp;event,void* viewer_void)
  {
      float x,y,z;
      event.getPoint(x,y,z);
      std::cout &lt;&lt; "X: " &lt;&lt; x &lt;&lt; " Y: " &lt;&lt; y &lt;&lt; " Z: " &lt;&lt; z &lt;&lt; std::endl;
  }
  
  boost::shared_ptr&lt;pcl::visualization::PCLVisualizer&gt; simpleVis (pcl::PointCloud&lt;pcl::PointXYZ&gt;::ConstPtr cloud)
  {
    boost::shared_ptr&lt;pcl::visualization::PCLVisualizer&gt; viewer (new pcl::visualization::PCLVisualizer ("3D Viewer"));
    viewer-&gt;setBackgroundColor (0, 0, 0);
    viewer-&gt;addPointCloud&lt;pcl::PointXYZ&gt; (cloud, filename);
    viewer-&gt;setPointCloudRenderingProperties (pcl::visualization::PCL_VISUALIZER_POINT_SIZE, 1, filename);
    viewer-&gt;addCoordinateSystem (1.0);
    viewer-&gt;initCameraParameters ();
    viewer-&gt;registerMouseCallback (mouseEventOccurred, (void*)&amp;viewer);
    viewer-&gt;registerPointPickingCallback(pointPickingOccured, (void*)&amp;viewer);
    viewer-&gt;spin();
    return (viewer);
  </code></pre>
  
  <p>//new Code</p>
  
  <pre><code>void pointPickingOccured( const pcl::visualization::PointPickingEvent &amp;event,void* viewer_void)
  {
      float x,y,z;
      event.getPoint(x,y,z);
      pointIndex = event.getPointIndex();
      std::cout &lt;&lt;"Point No. " &lt;&lt; pointIndex &lt;&lt;" ";
      std::cout &lt;&lt; "X: " &lt;&lt; x &lt;&lt; " Y: " &lt;&lt; y &lt;&lt; " Z: " &lt;&lt; z &lt;&lt; std::endl;
  
      viewer-&gt;updateSphere(cloud-&gt;points[pointIndex], 0.03, 255, 0, 0, "pt");
      viewer-&gt;spinOnce (100);
      boost::this_thread::sleep (boost::posix_time::microseconds (100000));
  }
  
  
  void simpleVis (pcl::PointCloud&lt;pcl::PointXYZ&gt;::ConstPtr cloud)
  {
    viewer-&gt;setBackgroundColor (0, 0, 0);
    viewer-&gt;addPointCloud&lt;pcl::PointXYZ&gt; (cloud, filename);
    viewer-&gt;setPointCloudRenderingProperties (pcl::visualization::PCL_VISUALIZER_POINT_SIZE, 1, filename);
    viewer-&gt;registerPointPickingCallback(pointPickingOccured, (void*)&amp;viewer);
    viewer-&gt;addCoordinateSystem (1.0);
    viewer-&gt;initCameraParameters ();
    viewer-&gt;addSphere(cloud-&gt;points[pointIndex], 0.03, "pt", 0); viewer-&gt;spin();}
  </code></pre>