Graphical input from mouse with Opencv
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Does OpenCV has a function similar to [ginput](http://www.mathworks.nl/help/techdoc/ref/ginput.html)? After the user denotes the points in the image, the ginput function can retrieve their coordinates in the program. I was wondering whether OpenCV has similar functions. If OpenCV does not have this function, can any other C++ image processing libraries offer similar functionality? Thanks.