#include <opencv\cv.h>
#include <opencv/highgui.h>
#include <iostream>


using namespace std;
using namespace cv;

Mat org,img,tmp,dst;

Rect rect;

void on_mouse(int event, int x, int y, int flags, void* ustc)
{
    static CvPoint pre_pt = { -1, -1 };
    static CvPoint cur_pt = { -1, -1 };
    char temp[16];

    if (event == CV_EVENT_LBUTTONDOWN)
    {
        org.copyTo(img);
        /*cvCopy(org, img);*/
        sprintf(temp, "(%d,%d)", x, y);
        pre_pt = cvPoint(x, y);
        putText(img, temp, pre_pt, 1,1, Scalar(0, 0, 255),1);
        circle(img, pre_pt, 3, cvScalar(255, 0, 0, 0), CV_FILLED, CV_AA, 0);
        imshow("img", img);
        img.copyTo(tmp);
    }
    else if (event == CV_EVENT_MOUSEMOVE && !(flags & CV_EVENT_FLAG_LBUTTON))
    {
        tmp.copyTo(img);
        sprintf(temp, "(%d,%d)", x, y);
        cur_pt = cvPoint(x, y);
        putText(img, temp, cur_pt, 1, 1, Scalar(0, 0, 255), 1);
        imshow("img", img);
    }
    else if (event == CV_EVENT_MOUSEMOVE && (flags & CV_EVENT_FLAG_LBUTTON))
    {
        tmp.copyTo(img);
        sprintf(temp, "(%d,%d)", x, y);
        cur_pt = cvPoint(x, y);
        putText(img, temp, cur_pt, 1, 1, Scalar(0, 0, 255), 1);
        rectangle(img, pre_pt, cur_pt, cvScalar(0, 255, 0, 0), 1, 8, 0);
        imshow("img", img);
    }
    else if (event == CV_EVENT_LBUTTONUP)
    {
        tmp.copyTo(img);
        sprintf(temp, "(%d,%d)", x, y);
        cur_pt = cvPoint(x, y);
        putText(img, temp, cur_pt, 1, 1, Scalar(0, 0, 255), 1);
        circle(img, cur_pt, 3, cvScalar(255, 0, 0, 0), CV_FILLED, CV_AA, 0);
        rectangle(img, pre_pt, cur_pt, cvScalar(0, 255, 0, 0), 1, 8, 0);
        imshow("img", img);
        img.copyTo(tmp);
        int width = abs(pre_pt.x - cur_pt.x);
        int height = abs(pre_pt.y - cur_pt.y);
        if (width == 0 || height == 0)
            return;
        dst = Mat(cvSize(width, height), org.type());

        if (pre_pt.x<cur_pt.x && pre_pt.y<cur_pt.y)
        {
            rect = Rect(pre_pt.x, pre_pt.y, width, height);
        }
        else if (pre_pt.x>cur_pt.x && pre_pt.y<cur_pt.y)
        {
            rect = Rect(cur_pt.x, pre_pt.y, width, height);
        }
        else if (pre_pt.x>cur_pt.x && pre_pt.y>cur_pt.y)
        {
            rect = Rect(cur_pt.x, cur_pt.y, width, height);
        }
        else if (pre_pt.x<cur_pt.x && pre_pt.y>cur_pt.y)
        {
            rect = Rect(pre_pt.x, cur_pt.y, width, height);
        }
        dst = Mat(img, rect);
        cvNamedWindow("dst", 1);
        imshow("dst", dst);
        waitKey();
    }
}

int main()
{
    org = imread("D:\\Source Code\\grabcut\\Grabcut\\a.jpg");
    img = org.clone();
    tmp = org.clone();
    int a = org.at<Vec3b>(1, 1)[0];
    cvNamedWindow("img", 1);
    cvSetMouseCallback("img", on_mouse, 0);
    imshow("dst", img);
    cvWaitKey(0);
}