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How to call setmousecallback opencv in button winforms?

asked 2019-11-22 02:34:52 -0600

Walid gravatar image

updated 2019-11-24 21:47:47 -0600

I want to get coordinate X/Y from image, how to use setmousecallback opencv in button winforms? Thank you Button code :

private: System::Void b_SAsel_Click(System::Object^  sender, System::EventArgs^  e) {
             namedWindow("Display window", 0);
             Mat img = imread("PIC 1.jpg");
             setMouseCallback("Display window", mouseHandler, &img);
}

mousehandler code :

static void mouseHandler(int event, int x, int y, int, void* imgptr){
    Point2f coordinate[30][30];
    int temp;

    RNG rng(12345);
    cv::Point pts[30];
    Mat shape, kontur;
    Mat res;

    if (event != 1) return;
    Mat & img = (*(Mat*)imgptr);
    cv::Point pt1 = cv::Point(x, y);
    temp++;
    pts[temp - 1] = cv::Point(x, y);
    cout << temp << endl;
    coordinate[temp][0] = Point2f(float(x), float(y));
    img.copyTo(shape);
    img.copyTo(kontur);
    .................
        ...........
}

i got this error : Error 10 error C2664: 'void cv::setMouseCallback(const cv::String &,cv::MouseCallback,void *)' : cannot convert argument 2 from 'void (__clrcall *)(int,int,int,int,void *)' to 'cv::MouseCallback' ...\guithes1\guithes\guithesDlg.h 395 1 GUITHES

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Comments

maybe you can cast the callback pointer:

setMouseCallback("Display window", (cv::MouseCallback)mouseHandler, &img);

but this is terrible, and won't work:

         Mat img = imread("PIC 1.jpg");
         setMouseCallback(....,...., &img);

img will get destroyed at the end of the function, and you have a dangling pointer in &img

you must NOT create that Mat in a local function, it has to stay alive for the wole lifetime of your program

berak gravatar imageberak ( 2019-11-25 01:42:29 -0600 )edit

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answered 2019-11-22 02:46:14 -0600

berak gravatar image

updated 2019-11-22 02:49:11 -0600

if you meant .Net winforms -- you can't.

there is no way opencv can interact with it.

(you'll have to write your own routines there)

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visual studio windows forms app c++, please check my program, thank you

Walid gravatar imageWalid ( 2019-11-24 21:48:55 -0600 )edit

forms app

don't.

berak gravatar imageberak ( 2019-11-25 03:58:51 -0600 )edit

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Asked: 2019-11-22 02:34:52 -0600

Seen: 300 times

Last updated: Nov 24 '19