/* * filestorage_sample demonstrate the usage of the opencv serialization functionality */ #include "opencv2/core/core.hpp" #include <iostream> #include <string> using std::string; using std::cout; using std::endl; using std::cerr; using std::ostream; using namespace cv; static void help(char** av) { cout << "\nfilestorage_sample demonstrate the usage of the opencv serialization functionality.\n" << "usage:\n" << av[0] << " outputfile.yml.gz\n" << "\n outputfile above can have many different extenstions, see below." << "\nThis program demonstrates the use of FileStorage for serialization, that is use << and >> in OpenCV\n" << "For example, how to create a class and have it serialize, but also how to use it to read and write matrices.\n" << "FileStorage allows you to serialize to various formats specified by the file end type." << "\nYou should try using different file extensions.(e.g. yaml yml xml xml.gz yaml.gz etc...)\n" << endl; } struct MyData { MyData() : A(0), X(0), id() { } explicit MyData(int) : A(97), X(CV_PI), id("mydata1234") { } int A; double X; string id; void write(FileStorage& fs) const //Write serialization for this class { fs << "{" << "A" << A << "X" << X << "id" << id << "}"; } void read(const FileNode& node) //Read serialization for this class { A = (int)node["A"]; X = (double)node["X"]; id = (string)node["id"]; } }; //These write and read functions must exist as per the inline functions in operations.hpp static void write(FileStorage& fs, const std::string&, const MyData& x){ x.write(fs); } static void read(const FileNode& node, MyData& x, const MyData& default_value = MyData()){ if(node.empty()) x = default_value; else x.read(node); } static ostream& operator<<(ostream& out, const MyData& m){ out << "{ id = " << m.id << ", "; out << "X = " << m.X << ", "; out << "A = " << m.A << "}"; return out; } int main(int ac, char** av) { cv::CommandLineParser parser(ac, av, "{@input||}{help h ||}" ); if (parser.has("help")) { help(av); return 0; } string filename = parser.get<string>("@input"); if (filename.empty()) { help(av); return 1; } //write { FileStorage fs(filename, FileStorage::WRITE); cout << "writing images\n"; fs << "images" << "["; fs << "image1.jpg" << "myfi.png" << "../data/baboon.jpg"; cout << "image1.jpg" << " myfi.png" << " ../data/baboon.jpg" << endl; fs << "]"; cout << "writing mats\n"; Mat R =Mat_<double>::eye(3, 3),T = Mat_<double>::zeros(3, 1); cout << "R = " << R << "\n"; cout << "T = " << T << "\n"; fs << "R" << R; fs << "T" << T; cout << "writing MyData struct\n"; MyData m(1); fs << "mdata" << m; cout << m << endl; } //read { FileStorage fs(filename, FileStorage::READ); if (!fs.isOpened()) { cerr << "failed to open " << filename << endl; help(av); return 1; } FileNode n = fs["images"]; if (n.type() != FileNode::SEQ) { cerr << "images is not a sequence! FAIL" << endl; return 1; } cout << "reading images\n"; FileNodeIterator it = n.begin(), it_end = n.end(); for (; it != it_end; ++it) { cout << (string)*it << "\n"; } Mat R, T; cout << "reading R and T" << endl; fs["R"] >> R; fs["T"] >> T; cout << "R = " << R << "\n"; cout << "T = " << T << endl; MyData m; fs["mdata"] >> m; cout << "read mdata\n"; cout << m << endl; cout << "attempting to read mdata_b\n"; //Show default behavior for empty matrix fs["mdata_b"] >> m; cout << "read mdata_b\n"; cout << m << endl; } cout << "Try opening " << filename << " to see the serialized data." << endl << endl; //read from string { cout << "Read data from string\n"; string dataString = "%YAML:1.0\n" "mdata:\n" " A: 97\n" " X: 3.1415926535897931e+00\n" " id: mydata1234\n"; MyData m; FileStorage fs(dataString, FileStorage::READ | FileStorage::MEMORY); cout << "attempting to read mdata_b from string\n"; //Show default behavior for empty matrix fs["mdata"] >> m; cout << "read mdata\n"; cout << m << endl; } //write to string { cout << "Write data to string\n"; FileStorage fs(filename, FileStorage::WRITE | FileStorage::MEMORY | FileStorage::FORMAT_YAML); cout << "writing MyData struct\n"; MyData m(1); fs << "mdata" << m; cout << m << endl; string createdString = fs.releaseAndGetString(); cout << "Created string:\n" << createdString << "\n"; } return 0; }