Documentation/Nightly/Developers/Tutorials/MigrationGuide/Slicer

MRML: Slicer 4.5: Introduction of vtkMRMLLabelMapVolumeNode

Rational:

Before vtkMRMLScalarVolumeNode was used for both scalar and label map volumes and the LabelMap custom MRML node attribute was used for distinguishing between them (0=scalar; 1=label map volume).

This made conversion between labelmap/scalar volumes very easy but made it difficult to customize behavior, display, processing of segmentation information.

Now a new vtkMRMLLabelMapVolumeNode class is used for storing segmentation information (still using vtkMRMLScalarVolume used as base class for backward compatibility; but in the future the base class may be changed to reflect that segmentation can be represented in various ways, not just as volumes).

Error message similar to:

 error: ‘class vtkMRMLScalarVolumeNode’ has no member named ‘SetLabelMap’
    outputVolumeNode->SetLabelMap(1);
                      ^

Solution (Update node selector configuration):

Replace lines like:

 nodeSelector.setNodeTypes(QStringList("vtkMRMLScalarVolumeNode"));
 nodeSelector.addAttribute("vtkMRMLScalarVolumeNode", "LabelMap", "1");

with:

 nodeSelector.setNodeTypes(QStringList("vtkMRMLLabelMapVolumeNode"));

Solution (Update UI file):

Replace lines like:

 <widget class="qMRMLNodeComboBox" name="InputLabelVolumeMRMLNodeComboBox">
  <property name="nodeTypes">
   <stringlist>
    <string>vtkMRMLScalarVolumeNode</string>
   </stringlist>
  </property>
  [...]
 </widget>

with:

 <widget class="qMRMLNodeComboBox" name="InputLabelVolumeMRMLNodeComboBox">
  <property name="nodeTypes">
   <stringlist>
    <string>vtkMRMLLabelMapVolumeNode</string>      <------------- Update Here
   </stringlist>
  </property>
  [...]
 </widget>

Solution (Update SafeDownCast usage):

Replace lines like:

  vtkMRMLScalarVolumeNode* labelmapVolumeNode = NULL;

  if (d->DisplayNode)
    {
    bgVolumeNode = vtkMRMLScalarVolumeNode::SafeDownCast(d->DisplayNode->GetBgVolumeNode());
    labelmapVolumeNode = vtkMRMLScalarVolumeNode::SafeDownCast(d->DisplayNode->GetLabelmapVolumeNode());
    }

with:

  vtkMRMLLabelMapVolumeNode* labelmapVolumeNode = NULL;

  if (d->DisplayNode)
    {
    bgVolumeNode = vtkMRMLScalarVolumeNode::SafeDownCast(d->DisplayNode->GetBgVolumeNode());
    labelmapVolumeNode = vtkMRMLLabelMapVolumeNode::SafeDownCast(d->DisplayNode->GetLabelmapVolumeNode());
    }

References:

• http://www.slicer.org/slicerWiki/index.php/Documentation/Labs/Segmentations#vtkMRMLLabelMapVolumeNode_integration
• http://viewvc.slicer.org/viewvc.cgi/Slicer4?view=revision&revision=24291