STYLE: Encapsulate NiftiImage qto_xyz mat44 data as Matrix<float,4,4>

Using `itk::Matrix<float, 4, 4>` (instead of `std::vector<float>`) to store the "qto_xyz" data from m_NiftiImage, as this `Matrix` template instantiation more closely resembles the original niftilib `mat44` data structure.
InsightSoftwareConsortium · Mar 25, 2022 · e00bad0 · e00bad0
1 parent 9325b2a
commit e00bad0
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Showing 3 changed files with 5 additions and 9 deletions.
diff --git a/Modules/Core/Common/include/itkMetaDataObject.h b/Modules/Core/Common/include/itkMetaDataObject.h
@@ -364,6 +364,7 @@ extern template class ITKCommon_EXPORT_EXPLICIT MetaDataObject<Array<char>>;
 extern template class ITKCommon_EXPORT_EXPLICIT MetaDataObject<Array<int>>;
 extern template class ITKCommon_EXPORT_EXPLICIT MetaDataObject<Array<float>>;
 extern template class ITKCommon_EXPORT_EXPLICIT MetaDataObject<Array<double>>;
+extern template class ITKCommon_EXPORT_EXPLICIT MetaDataObject<Matrix<float, 4, 4>>;
 extern template class ITKCommon_EXPORT_EXPLICIT MetaDataObject<Matrix<double>>;
 
 ITK_GCC_PRAGMA_DIAG_POP()

diff --git a/Modules/Core/Common/src/itkMetaDataObject.cxx b/Modules/Core/Common/src/itkMetaDataObject.cxx
@@ -43,6 +43,7 @@ template class ITKCommon_EXPORT MetaDataObject<Array<char>>;
 template class ITKCommon_EXPORT MetaDataObject<Array<int>>;
 template class ITKCommon_EXPORT MetaDataObject<Array<float>>;
 template class ITKCommon_EXPORT MetaDataObject<Array<double>>;
+template class ITKCommon_EXPORT MetaDataObject<Matrix<float, 4, 4>>;
 template class ITKCommon_EXPORT MetaDataObject<Matrix<double>>;
 template class ITKCommon_EXPORT MetaDataObject<std::vector<float>>;
 template class ITKCommon_EXPORT MetaDataObject<std::vector<double>>;

diff --git a/Modules/IO/NIFTI/src/itkNiftiImageIO.cxx b/Modules/IO/NIFTI/src/itkNiftiImageIO.cxx
@@ -999,15 +999,9 @@ NiftiImageIO::SetImageIOMetadataFromNIfTI()
 
   EncapsulateMetaData<float>(thisDic, "qfac", nim->qfac);
 
-  std::vector<float> qto_xyz;
-  for (int row = 0; row < 4; ++row)
-  {
-    for (int column = 0; column < 4; ++column)
-    {
-      qto_xyz.push_back(nim->qto_xyz.m[row][column]);
-    }
-  }
-  EncapsulateMetaData<std::vector<float>>(thisDic, "qto_xyz", qto_xyz);
+  // Use the ITK Matrix template instantiation that matches the `mat44` typedef from niftilib.
+  using Matrix44Type = Matrix<float, 4, 4>;
+  EncapsulateMetaData<Matrix44Type>(thisDic, "qto_xyz", Matrix44Type(nim->qto_xyz.m));
 }
 
 void