Fix issue with vtk warnings when segmentation data with gaps in the l…

…abel range are loaded

Region.cxx

@@ -46,6 +46,7 @@ Region::Region(unsigned short regionLabel, double regionColor[3], vtkImageData*
 	// XXX: USE GENERATE REGION EXTENTS FROM vktImageConnectivityFilter AND PASS THIS IN
 	//		ALSO REGION SIZE FROM FILTER
 
+	int numVoxels = 0;
 	for (int i = 0; i < numPoints; i++) {
 		if (scalars[i] == label) {
 			double* point = data->GetPoint(i);
@@ -56,9 +57,18 @@ Region::Region(unsigned short regionLabel, double regionColor[3], vtkImageData*
 			if (point[1] > extent[3]) extent[3] = point[1];
 			if (point[2] < extent[4]) extent[4] = point[2];
 			if (point[2] > extent[5]) extent[5] = point[2];
+
+			numVoxels++;
 		}
 	}
 
+	// Fix extent if no voxels with this label
+	if (numVoxels == 0) {
+		extent[0] = extent[1] = dataExtent[0];
+		extent[2] = extent[3] = dataExtent[2];
+		extent[4] = extent[5] = dataExtent[4];
+	}
+
 	voi = vtkSmartPointer<vtkExtractVOI>::New();
 	voi->SetInputDataObject(data);
 

VisualizationContainer.cxx

@@ -764,7 +764,14 @@ void VisualizationContainer::ExtractRegions() {
 	regions->RemoveAll();
 
 	for (int label = 1; label <= maxLabel; label++) {
-		regions->Add(new Region(label, labelColors->GetTableValue(label), labels));
+		Region* region = new Region(label, labelColors->GetTableValue(label), labels);
+
+		if (region->GetNumVoxels() > 0) {
+			regions->Add(new Region(label, labelColors->GetTableValue(label), labels));
+		}		
+		else {
+			delete region;
+		}
 	}
 }