OpenCV，在显示图像时读取用户文本输入（使用waitKey）

Question

I'm a bit stuck trying to get some user text input while using OpenCV.

I have developed an iterative program which opens an image, detects colors and displays them using standard cv::imshow() followed by the mandatory waitKey() . In this state, pressing any key should just process and display the next image.

The problem is I want to allow the user to optionally click the image displayed and input some text data. I tried to use cin >> mystring but it looks like the waitKey() is blocking the console, so anything i type is displayed but not took by cin as input UNTIL the waitKey ends. It is a problem since some times i would like to get more than one text input per image, so it would be nice to be able to use console and cin normally while waitKey is working.

¿Any idea on how to allow a user to input text while an image is being displayed? A solution to my problem would be nice, but any other idea or workaround is also welcomed.

Ty!

Answer 1

I have an idea about what you might be doing wrong - it would be great (for others landing here) if you posted your code too.

Like I suggested, you can set a mouse callback and get the string in that function. This worked fair enough for me:

std::string s("empty");
void on_mouse_click( int event, int x, int y, int, void* )
{
    if( event == EVENT_LBUTTONDOWN )    //are you missing this?
    {
        std::cout<<"enter string: ";
        std::cin>>s;
    }
}
int main()
{
    :
    :
    cv::imshow( "images", frame );
    cv::waitKey();
    std::cout<<s;
return 1;
}

The last display statement displays "empty" if I just hit a key directly. In case I click the image first, go back to console and type something, go back to image window and then hit a key, I get the string I enter instead.