Merge pull request #14284 from peterrum/vtu_ascii

Add DataOutBase::CompressionLevel::ascii

diff --cc include/deal.II/base/data_out_base.h
Simple merge

diff --cc source/base/data_out_base.cc
index 6ff70bee332c8de0acfdd82314463403ce0b7fed,60e90d8e47e1b3cd9559809ef208a9dc49ce0a12..a9377296c508e43788e6a2596e4b33d84cdeecb0
--- 1/source/base/data_out_base.cc
--- 2/source/base/data_out_base.cc
+++ b/source/base/data_out_base.cc
@@@ -5820,13 -5835,10 +5853,14 @@@ namespace DataOutBas
      else
        out << '.';
      out << "\n-->\n";
 -    out << "<VTKFile type=\"UnstructuredGrid\" version=\"0.1\"";
 +
 +    if (flags.write_higher_order_cells)
 +      out << "<VTKFile type=\"UnstructuredGrid\" version=\"2.2\"";
 +    else
 +      out << "<VTKFile type=\"UnstructuredGrid\" version=\"0.1\"";
  #ifdef DEAL_II_WITH_ZLIB
-     out << " compressor=\"vtkZLibDataCompressor\"";
+     if (flags.compression_level != CompressionLevel::plain_text)
+       out << " compressor=\"vtkZLibDataCompressor\"";
  #endif
  #ifdef DEAL_II_WORDS_BIGENDIAN
      out << " byte_order=\"BigEndian\"";