Mesh_3 Polyhedron demo : Added support for vtk images (vti format) (#…

…7729)

## Summary of Changes

Added support for vtk image (.vti files) opening in the demo in the
plugin Mesh_3/Io_image_plugin

## Release Management

* Affected package(s): Mesh_3
* Issue(s) solved (if any): 
* Feature/Small Feature (if any):
* License and copyright ownership:

Polyhedron/demo/Polyhedron/Plugins/Mesh_3/CMakeLists.txt

@@ -34,14 +34,14 @@ if(ITK_FOUND)
   target_link_libraries(mesh_3_plugin PUBLIC CGAL::ITK_support)
 endif(ITK_FOUND)
 
-find_package(VTK QUIET COMPONENTS vtkImagingGeneral vtkIOImage NO_MODULE)
+find_package(VTK QUIET COMPONENTS vtkImagingGeneral vtkIOImage vtkIOXML NO_MODULE)
 if(VTK_FOUND)
   if(VTK_USE_FILE)
     include(${VTK_USE_FILE})
   endif()
   if("${VTK_VERSION_MAJOR}" GREATER "5" OR VTK_VERSION VERSION_GREATER 5)
     if(TARGET VTK::IOImage)
-      set(VTK_LIBRARIES VTK::IOImage VTK::ImagingGeneral)
+      set(VTK_LIBRARIES VTK::IOImage VTK::ImagingGeneral VTK::IOXML)
     endif()
     if(NOT VTK_LIBRARIES)
       message(STATUS "NOTICE: DICOM files (.dcm) require the VTK libraries, and will not be readable.")

Polyhedron/demo/Polyhedron/Plugins/Mesh_3/Io_image_plugin.cpp

@@ -54,8 +54,10 @@
 #include <CGAL/IO/read_vtk_image_data.h>
 
 #include <vtkNew.h>
+#include <vtkSmartPointer.h>
 #include <vtkStringArray.h>
 #include <vtkImageData.h>
+#include <vtkXMLImageDataReader.h>
 #include <vtkDICOMImageReader.h>
 #include <vtkBMPReader.h>
 #include <vtkNIFTIImageReader.h>
@@ -77,6 +79,23 @@
 #include <iostream>
 #include <locale>
 
+template <class vtkReader>
+bool
+load_vtk_file(QFileInfo fileinfo, Image* image)
+{
+#ifdef CGAL_USE_VTK
+    vtkNew<vtkReader> reader;
+    reader->SetFileName(fileinfo.filePath().toUtf8());
+    reader->Update();
+    auto vtk_image = reader->GetOutput();
+    vtk_image->Print(std::cerr);
+    *image = CGAL::IO::read_vtk_image_data(vtk_image); // copy the image data
+    return true;
+#else
+    return false;
+#endif
+}
+
 // Covariant return types don't work for scalar types and we cannot
 // have templates here, hence this unfortunate hack.
 
@@ -1089,6 +1108,7 @@ QString Io_image_plugin::nameFilters() const
   return QString("Inrimage files (*.inr *.inr.gz) ;; "
                  "Analyze files (*.hdr *.img *.img.gz) ;; "
                  "Stanford Exploration Project files (*.H *.HH) ;; "
+                 "VTK image files (*.vti) ;; "
                  "NRRD image files (*.nrrd) ;; "
                  "NIFTI image files (*.nii *.nii.gz)");
 }
@@ -1121,46 +1141,47 @@ void convert(Image* image)
   image->image()->wordKind = WK_FLOAT;
 }
 
+
 QList<Scene_item*>
 Io_image_plugin::load(QFileInfo fileinfo, bool& ok, bool add_to_scene)
 {
   ok = true;
   QApplication::restoreOverrideCursor();
   Image* image = new Image;
 
+  QString warningMessage;
+  // read a vti file
+  if(fileinfo.suffix() == "vti")
+  {
+#ifdef CGAL_USE_VTK
+    ok = load_vtk_file<vtkXMLImageDataReader>(fileinfo, image);
+#else
+    ok = false;
+    warningMessage = "VTK is required to read VTI files";
+#endif
+  }
+
   // read a nrrd file
-  if(fileinfo.suffix() == "nrrd")
+  else if(fileinfo.suffix() == "nrrd")
   {
 #ifdef CGAL_USE_VTK
-    vtkNew<vtkNrrdReader> reader;
-    reader->SetFileName(fileinfo.filePath().toUtf8());
-    reader->Update();
-    auto vtk_image = reader->GetOutput();
-    vtk_image->Print(std::cerr);
-    *image = CGAL::IO::read_vtk_image_data(vtk_image); // copy the image data
+    ok = load_vtk_file<vtkNrrdReader>(fileinfo, image);
 #else
-    CGAL::Three::Three::warning("VTK is required to read NRRD files");
-    delete image;
-    return QList<Scene_item*>();
+    ok = false;
+    warningMessage = "VTK is required to read NRRD files";
 #endif
   }
 
   // read a NIFTI file
-  if(fileinfo.suffix() == "nii"
+  else if(fileinfo.suffix() == "nii"
     || (   fileinfo.suffix() == "gz"
         && fileinfo.fileName().endsWith(QString(".nii.gz"), Qt::CaseInsensitive)))
   {
 #ifdef CGAL_USE_VTK
-    vtkNew<vtkNIFTIImageReader> reader;
-    reader->SetFileName(fileinfo.filePath().toUtf8());
-    reader->Update();
-    auto vtk_image = reader->GetOutput();
-    vtk_image->Print(std::cerr);
-    *image = CGAL::IO::read_vtk_image_data(vtk_image); // copy the image data
+    ok = load_vtk_file<vtkNIFTIImageReader>(fileinfo, image);
 #else
-    CGAL::Three::Three::warning("VTK is required to read NIfTI files");
-    delete image;
-    return QList<Scene_item*>();
+    ok = false;
+    warningMessage = "VTK is required to read NifTI files";
 #endif
   }
 
@@ -1267,11 +1288,16 @@ Io_image_plugin::load(QFileInfo fileinfo, bool& ok, bool add_to_scene)
     if(!success)
     {
       ok = false;
-      delete image;
-      return QList<Scene_item*>();
     }
   }
 
+  if (!ok) {
+    if (warningMessage.length() > 0)
+        CGAL::Three::Three::warning(warningMessage);
+    delete image;
+    return QList<Scene_item*>();
+  }
+
   // Get display precision
   QDialog dialog;
   ui.setupUi(&dialog);