Hello,
When you need to read an image from disk, you go for imread. Nevertheless, I need to istantiate a Mat using raw data.
Consider this code:
#include <opencv2/highgui/highgui.hpp>
#include <iostream>
#include <fstream>
#include <memory>
#include <string>
int main()
{
std::string path;
std::cout << "Path: ";
std::getline(std::cin, path);
std::ifstream file(path, std::ifstream::binary); // raw data
if (!file.is_open())
{
std::cout << "Could not open file." << std::endl;
return 1;
}
file.seekg(0, file.end);
auto fileSize = file.tellg();
file.seekg(0, file.beg);
std::cout << fileSize << "." << std::endl;
std::unique_ptr<unsigned char> bufferPtr(new unsigned char[fileSize]);
file.read(reinterpret_cast<char *>(bufferPtr.get()), fileSize);
if (!file)
{
std::cout << "Could not read all data." << std::endl;
return 1;
}
std::cout << "Enter file width: "; //how can I figure this
int width;
std::cin >> width;
std::cout << "Enter file height: "; // and this out?
int height;
std::cin >> height;
std::vector<unsigned char> buffer( bufferPtr.get(), bufferPtr.get() + fileSize);
cv::Mat img(height, width, CV_8UC3, buffer.data());
// as well as ^^^^^^^ this ?
if (img.empty())
{
std::cerr << "Could not load Mat object." << std::endl;
return 1;
}
cv::namedWindow("window", CV_WINDOW_AUTOSIZE);
cv::imshow("window", img);
cv::waitKey(0);
return 0;
}
It works most of the times indefinitely: sometimes it crashes (SIGSEGV when converting the format), sometimes shows wrong stuff.
Where am I wrong? How can I get stuff like width, height and the format as imread does?