DiskImageView.cpp

This code demonstrates how to create an image view on disk and write/read data to/from it.

This code demonstrates how to create an image view on disk and write/read data to/from it.The code creates a 3D image of size 100x100x100 without allocating any CPU memory, and writes a line of data in each slice. Finally, it then reads and prints the value of the last written sample .

#include <iostream>
#include <vector>
 
#include <iolink/view/ImageViewFactory.h>
 
using namespace iolink;
 
std::shared_ptr<ImageView>
diskImageView()
{
  const VectorXu64 shape = VectorXu64{100, 100, 100};
  const DataType dt = DataTypeId::DOUBLE;
 
  // create an image view on disk
  auto image = ImageViewFactory::createOnDisk(shape, dt);
 
  std::vector<double> lineBuffer(shape[0]);
  const VectorXu64 lineSize{shape[0], 1, 1};
 
  std::cout << "Writing data slice by slice, line by line" << std::endl;
 
  // write data slice by slice, line by line with a growing value
  double valueInit = 0;
  for (size_t i = 0; i < shape[2]; ++i)
  {
    for (size_t j = 0; j < shape[1]; ++j)
    {
      const RegionXu64 lineRegion(VectorXu64{0, j, i}, lineSize);
      std::fill(lineBuffer.begin(), lineBuffer.end(), valueInit);
      image->writeRegion(lineRegion, lineBuffer.data());
      valueInit++;
    }
  }
 
  std::cout << "Writing completed" << std::endl;
 
  return image;
}
 
int
main(int argc, char** argv)
{
  auto image = diskImageView();
 
  std::cout << "Reading Last Sample" << std::endl;
  double value;
  image->read(VectorXu64{99, 99, 99}, &value);
  std::cout << "Last Sample Value: " << value << std::endl;
 
  return EXIT_SUCCESS;
}