OpenCV从一组点画一条线

Question

I am trying to draw a line that will link up center points of a bounding box, The points are stored in a vector as the center moves from frame to frame.

Now I am trying to use a CvLine to linke these points together with a line. I am following This Opencv Documentation . But CvLine function isynt happy with the parameters I give it.

Here is the code:

vector<Point> Rightarm(20);


vector<Point> Leftarm(20);

    vector<Point>::const_iterator RightIter;
    vector<Point>::const_iterator LeftIter;



   Point center = Point(oko[0].x + (oko[0].width/2), oko[0].y + (oko[0].height/2));
    cout<<"Center Point of Box: 0 is: " <<center<<endl;

    double area = (oko[0].width * oko[0].height);
    cout<<"The Area of Box: 0 is: " <<area<<endl;

    Point center1 = Point(oko[1].x + (oko[1].width/2), oko[1].y + (oko[1].height/2));
    cout<<"Center Point of Box: 1 is: " <<center1<<endl;

    double area1 = (oko[1].width * oko[1].height);
    cout<<"The Area of Box: 1 is: " <<area1<<endl;



Rightarm.push_back(center);
    Leftarm.push_back(center1); 

    if(oko[0].x > oko[1].x)
    {

    }
        else
        {

        }


    for(RightIter = Rightarm.begin(); RightIter != Rightarm.end(); ++RightIter)
    {
        circle(drawing, *RightIter, 3, Scalar(0,0,255), CV_FILLED); 
    }

    if(Rightarm.size() == 20)
        {
            Rightarm.clear();

        }

    for(LeftIter = Leftarm.begin(); LeftIter != Leftarm.end(); ++LeftIter)
    {
        circle(drawing, *LeftIter, 3, Scalar(0,255,0), CV_FILLED);
    }

        if(Rightarm.size() == 20)
        {
            Leftarm.clear();

        }

    cvLine(drawing, center.x, center.y, Scalar(255,255,255),1 ,8 ,CV_AA);

    imshow(window_Input, frame);
    imshow(window_Output, drawing);

Can anyone see where I am going wrong with this...?

Answer 1

You are giving wrong arguments and one extra argument to line funciton. The documentation you pointed to is for Python interface, that too the older one using cv . Assuming that you have a recent version of OpenCV it is better if you use the new C++ interface or cv2 interface in Python.

you have to use line function like

cvLine(
img,       // image to draw on
center,    // starting end point of line segment of type cv::Point
center1,   // other end of line segment
Scalar(0, 255, 0), //green colour
1         // thickness of line
CV_AA     // anti aliased line type
);

documentation is here

Answer 2

Maybe like this:

struct centerpoint {
  int x;
  int y;
} center1,center2;

(...) //Define values for centers.

cvLine( drawing, 
        cvPoint(center1.x, center1.y),
        cvPoint(center2.x, center2.y),
        Scalar(255,255,255), 1, 8 , CV_AA);

Don't forget to vote all the answers you like and accept the one that works.

Answer 3

cvLine在两点之间画线，您应该给它两个cv :: Point，但不能给定center.x nad center.y