Question

我正在尝试构建一个程序，我使用gstreamer和opencv来操作图像。这是我的主要文件：

public class MessageEventArgs : EventArgs
{
    public string Message { get; private set;}

    public MessageEventArgs(string message)
    {
        Message = message;
    }
}

public class MyReceiver : IDisposable
{
    private Thread _thread;
    private ManualResetEvent _terminating = new ManualResetEvent(false);

    public void Start()
    {
        _thread = new Thread(() =>
        {
            try
            {
                IntPtr hPipe;
                string dwWritten;
                byte[] buffer = new byte[BUFSIZE];

                NamedPipeClientStream pipeClient = new NamedPipeClientStream(".","testpipe", PipeDirection.In, PipeOptions.WriteThrough);

                if (pipeClient.IsConnected != true) { pipeClient.Connect(); }

                StreamReader sr = new StreamReader(pipeClient);

                string temp;

                while(!_terminating.WaitOne(0))
                {
                    temp = "";
                    temp = sr.ReadLine();
                    if (temp != null)
                    {
                        OnMessage?.Invoke(temp);
                    }
                    if (temp != "QUIT")
                    {
                        sw.WriteLine("Response");
                        sw.Flush();
                        pipeClient.WaitForPipeDrain();
                    }
                    else
                    {
                        sw.WriteLine("Response");
                        _terminating.Set();
                    }
                }
            }
            catch (Exception ex)
            {
                throw new Exception("Exception: " + ex.Message);
            }               

        });

        _thread.Start();
    }

    public void Dispose()
    {
        _terminating.Set();
        _thread.Join();
    }

    public event EventHandler<MessageEventArgs> OnMessage;
}

// Example of how to use the Receiver class.
public class Form1: Form
{
    MyReceiver _receiver;

    public Form1()
    {
        InitializeComponent();
        this.FormClosed += FormClosed;

        _receiver = new MyReceiver();
        _receiver.OnMessage += MessageReceived;
        _receiver.Start();
    }

    public void MessageReceived(object sender, MessageEventArgs e)
    {
        // You need to invoke this, because the event is run on other than the UI thread.
        this.Invoke(new Action(() =>
        {
            listBox1.Items.Add(e.Message);
        });
    }

    public void FormClosed(object sender, EventArgs e)
    {
        _receiver.Dispose();
    }
}

这是.pro文件：

#include "GstSource.hpp"
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/highgui/highgui_c.h>  
#include <iostream>

static const int Key_Escape  =  27;

int main(int argc, char *argv[])
{
cv::namedWindow("Gstreamer");
cvMoveWindow("Gstreamer",100,100);

GstreamerPlayer player;
if (! player.open("videotestsrc") )
    std::cerr << "Unable to open pipeline" << std::endl;

if ( !player.setWidth(640) || !player.setHeight(480) ) {
    std::cerr << "Unable to change resolution" << std::endl;
    return 1;
}


bool fps_readed = false;
while (true) {
    if (!player.grabFrame()) {
        std::cerr << "Failed to grab frame" << std::endl;
        break;
    }
    GstreamerImage * frame = player.getImage();
    if (!frame) {
        std::cerr << "Failed to retrieve frame" << std::endl;
        break;
    }

    if (!fps_readed) {
        std::cout << "Video playing at " << player.getFps() << " fps" <    std::endl;
        fps_readed = true;
    }

    cv::Mat canvas = cv::Mat(frame->height, frame->width, CV_8UC3, frame->data);
    if ( canvas.empty() )
        break;
    cv::imshow("Gstreamer", canvas);

    int key = cv::waitKey(10);
    if (key == Key_Escape)
        break;
}
}

我得到147这种类型的错误：未定义引用.....因为许多函数被声明但未定义。他们的定义在哪里？我怎么能包括他们的定义？

Answer 1

使用PKGCONFIG怎么样：

在你的专业人士：

CONFIG += pkgconfig
PKGCONFIG += gstreamer-1.0 gstreamer-video-1.0

您可以在shell中查看您拥有它们：

pkg-config --list-all | grep gst

如果指向正确的库，则检查一个包：

pkg-config --cflags gstreamer-1.0

应打印：

-pthread -I / usr / local / include / gstreamer-1.0 -I / usr / local / lib / gstreamer-1.0 / include -I / usr / include / glib-2.0 -I / usr / lib / x86_64- linux-gnu / glib-2.0 / include -L / usr / local / lib -lgstreamer-1.0 -lgobject-2.0 -lglib-2.0

如果您没有.pc文件，则不会列出..您需要安装-dev版本的gstreamer软件包。

还有一个env变量可用于告诉pkg config在哪里查找.pc文件：

PKG_CONFIG_PATH=/home/something/gst/1.6/gst-devtools/validate/pkgconfig

Here有人试图以这种方式链接opencv ..

对gst_element_register Qtcreator的unfind引用

1 个答案: