pointcloudvtkwriter.hh

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// -*- mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
// vi: set et ts=4 sw=4 sts=4:
//
// SPDX-FileCopyrightInfo: Copyright © DuMux Project contributors, see AUTHORS.md in root folder
// SPDX-License-Identifier: GPL-3.0-or-later
//
#ifndef DUMUX_POINTCLOUD_VTK_WRITER_HH
#define DUMUX_POINTCLOUD_VTK_WRITER_HH
 
#include <string>
#include <vector>
#include <list>
#include <fstream>
#include <iomanip>
 
#include <dune/common/fvector.hh>
#include <dune/common/exceptions.hh>
#include <dune/common/path.hh>
#include <dune/grid/io/file/vtk/common.hh>
 
namespace Dumux {
 
template<class Scalar, class GlobalPosition>
class PointCloudVtkWriter
{
    // GlobalPosition is used for the point coordinates, DimWorldVector for the actual data.
    // GlobalPosition's ctype does not necessarily equal Scalar.
    using DimWorldVector = Dune::FieldVector<Scalar, GlobalPosition::size()>;
 
    static constexpr unsigned int precision = 6;
    static constexpr unsigned int numBeforeLineBreak = 15;
 
    template<class ContainerType>
    class VTKFunction
    {
    public:
        VTKFunction(const ContainerType& data, const std::string& name, const int numComponents) : data_(data), name_(name), numComponents_(numComponents)
        {}
 
        const std::string& name() const
        {
            return name_;
        }
 
        int numComponents() const
        {
            return numComponents_;
        }
 
        auto& operator() (const int idx) const  { return data_[idx]; }
 
        decltype(auto) begin() const
        {
            return data_.begin();
        }
 
        decltype(auto) end() const
        {
            return data_.end();
        }
 
        int size() const
        {
            return data_.size();
        }
 
    private:
        const ContainerType& data_;
        const std::string name_;
        const int numComponents_;
    };
 
 
public:
    using ScalarFunction = VTKFunction<std::vector<Scalar>>;
    using VectorFunction = VTKFunction<std::vector<DimWorldVector>>;
 
 
    PointCloudVtkWriter(const std::vector<GlobalPosition>& coordinates) : coordinates_(coordinates)
    {}
 
    void write(const std::string& name, Dune::VTK::OutputType type = Dune::VTK::ascii)
    {
        auto filename = getSerialPieceName(name, "");
 
        std::ofstream file;
        file.open(filename);
        writeHeader_(file);
        writeCoordinates_(file, coordinates_);
        writeDataInfo_(file);
 
        for (auto&& data : scalarPointData_)
            writeData_(file, data);
 
        for (auto&& data :vectorPointData_)
            writeData_(file, data);
 
        if (!scalarPointData_.empty() || !vectorPointData_.empty())
            file << "</PointData>\n";
 
        file << "</Piece>\n";
        file << "</PolyData>\n";
        file << "</VTKFile>";
 
        clear();
        file.close();
    }
 
    void pwrite(const std::string & name,  const std::string & path, const std::string & extendpath,
                Dune::VTK::OutputType type = Dune::VTK::ascii)
    {
        DUNE_THROW(Dune::NotImplemented, "parallel point cloud vtk output not supported yet");
    }
 
    void addPointData(const std::vector<Scalar>& v, const std::string &name)
    {
        assert(v.size() == coordinates_.size());
        scalarPointData_.push_back(ScalarFunction(v, name, 1));
    }
 
    void addPointData(const std::vector<DimWorldVector>& v, const std::string &name)
    {
        assert(v.size() == coordinates_.size());
        vectorPointData_.push_back(VectorFunction(v, name, 3));
    }
 
    void clear()
    {
        scalarPointData_.clear();
        vectorPointData_.clear();
    }
 
    std::string getSerialPieceName(const std::string& name,
                                   const std::string& path) const
    {
      static const std::string extension = ".vtp";
 
      return Dune::concatPaths(path, name+extension);
    }
 
    std::string getParallelHeaderName(const std::string& name,
                                      const std::string& path,
                                      int commSize) const
    {
      std::ostringstream s;
      if(path.size() > 0) {
        s << path;
        if(path[path.size()-1] != '/')
          s << '/';
      }
      s << 's' << std::setw(4) << std::setfill('0') << commSize << '-';
      s << name;
      s << ".pvtp";
      return s.str();
    }
 
 
private:
    void writeHeader_(std::ostream& file)
    {
        std::string header = "<?xml version=\"1.0\"?>\n";
                    header += "<VTKFile type=\"PolyData\" version=\"0.1\" byte_order=\"LittleEndian\">\n";
                    header += "<PolyData>\n";
                    header += "<Piece NumberOfLines=\"0\" NumberOfPoints=\"" + std::to_string(coordinates_.size()) + "\">\n";
        file << header;
    }
 
    void writeDataInfo_(std::ostream& file)
    {
        std::string scalarName;
        std::string vectorName;
        bool foundScalar = false;
        bool foundVector = false;
 
        for(auto&& data : scalarPointData_)
        {
            if(data.numComponents() == 1 && !foundScalar)
            {
                scalarName = data.name();
                foundScalar = true;
                continue;
            }
 
            if(data.numComponents() > 1 && !foundVector)
            {
                vectorName = data.name();
                foundVector = true;
            }
        }
 
        for(auto&& data : vectorPointData_)
        {
            if(data.numComponents() > 1 && !foundVector)
            {
                vectorName = data.name();
                foundVector = true;
            }
        }
 
        if(foundScalar)
            if(foundVector)
                file << "<PointData Scalars=\"" << scalarName << "\" Vectors=\"" << vectorName <<"\">\n";
            else
                file << "<PointData Scalars=\"" << scalarName << "\">\n";
        else if(foundVector)
            file << "<PointData Vectors=\"" << vectorName << "\">\n";
        else
            return;
    }
 
    void writeCoordinates_(std::ostream& file, const std::vector<GlobalPosition>& positions)
    {
        // write the positions to the file
        file << "<Points>\n";
        file << "<DataArray type=\"Float32\" Name=\"Coordinates\" NumberOfComponents=\"3\" format=\"ascii\">\n";
        int counter = 0;
        for(auto&& x : positions)
        {
            file << x ;
 
            if(x.size() == 1)
                file << " 0 0 ";
            if(x.size() == 2)
                file << " 0 ";
            if(x.size() == 3)
                file << " ";
 
            // introduce a line break after a certain time
            if((++counter)  > numBeforeLineBreak)
            {
                file << std::endl;
                counter = 0;
            }
        }
        file << "\n</DataArray>\n";
        file << "</Points>\n";
    }
 
    template<class T>
    void writeData_(std::ostream& file, const T& data)
    {
        file << "<DataArray type=\"Float32\" Name=\"" << data.name() << "\" NumberOfComponents=\"" << data.numComponents() << "\" format=\"ascii\">\n";
        int counter = 0;
        for(auto&& value : data)
        {
            // forward to specialized function
            writeToFile_(file, value);
 
            // introduce a line break after a certain time
            if((++counter)  > numBeforeLineBreak)
            {
                file << std::endl;
                counter = 0;
            }
        }
        file << "\n</DataArray>\n";
    }
 
    void writeToFile_(std::ostream& file, const Scalar& s)
    {
        file << s << " ";
    }
 
    void writeToFile_(std::ostream& file, const DimWorldVector& g)
    {
        assert(g.size() > 1 && g.size() < 4);
        if(g.size() < 3)
            file << g << " 0 ";
        else
            file << g << " ";
    }
 
    const std::vector<GlobalPosition>& coordinates_;
    std::list<ScalarFunction> scalarPointData_;
    std::list<VectorFunction> vectorPointData_;
};
} // end namespace Dumux
 
#endif