OpenCV_4.2.0/opencv_contrib-4.2.0/modules/hdf/samples/read_write_attributes.cpp

94 lines
2.5 KiB
C++

/**
* @file read_write_attributes.cpp
* @author Fangjun Kuang <csukuangfj dot at gmail dot com>
* @date December 2017
*
* @brief It demonstrates how to read and write attributes inside the
* root group.
*
* Currently, only the following datatypes can be used as attributes:
* - cv::String
* - int
* - double
* - cv::InputArray (n-d continuous multichannel arrays)
*
* Although HDF supports associating attributes with both datasets and groups,
* only support for the root group is implemented by OpenCV at present.
*/
//! [tutorial]
#include <iostream>
#include <opencv2/core.hpp>
#include <opencv2/hdf.hpp>
using namespace cv;
static void read_write_attributes()
{
String filename = "attributes.h5";
//! [tutorial_open_file]
Ptr<hdf::HDF5> h5io = hdf::open(filename);
//! [tutorial_open_file]
//! [tutorial_write_mat]
String attr_mat_name = "array attribute";
Mat attr_mat;
attr_mat = (cv::Mat_<float>(2, 3) << 0, 1, 2, 3, 4, 5, 6);
if (!h5io->atexists(attr_mat_name))
h5io->atwrite(attr_mat, attr_mat_name);
//! [tutorial_write_mat]
//! [snippets_write_str]
String attr_str_name = "string attribute";
String attr_str = "Hello HDF5 from OpenCV!";
if (!h5io->atexists(attr_str_name))
h5io->atwrite(attr_str, attr_str_name);
//! [snippets_write_str]
String attr_int_name = "int attribute";
int attr_int = 123456;
if (!h5io->atexists(attr_int_name))
h5io->atwrite(attr_int, attr_int_name);
String attr_double_name = "double attribute";
double attr_double = 45678.123;
if (!h5io->atexists(attr_double_name))
h5io->atwrite(attr_double, attr_double_name);
// read attributes
Mat expected_attr_mat;
int expected_attr_int;
double expected_attr_double;
//! [snippets_read_str]
String expected_attr_str;
h5io->atread(&expected_attr_str, attr_str_name);
//! [snippets_read_str]
//! [tutorial_read_mat]
h5io->atread(expected_attr_mat, attr_mat_name);
//! [tutorial_read_mat]
h5io->atread(&expected_attr_int, attr_int_name);
h5io->atread(&expected_attr_double, attr_double_name);
// check results
CV_Assert(norm(attr_mat - expected_attr_mat) < 1e-10);
CV_Assert(attr_str.compare(expected_attr_str) == 0);
CV_Assert(attr_int == expected_attr_int);
CV_Assert(fabs(attr_double - expected_attr_double) < 1e-10);
//! [tutorial_close_file]
h5io->close();
//! [tutorial_close_file]
}
int main()
{
read_write_attributes();
return 0;
}
//! [tutorial]