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//--------------------------------------【程序说明】-------------------------------------------
//        程序说明：《OpenCV3编程入门》OpenCV2版书本附赠示例程序11
//        程序描述：找到最小的封闭轮廓的图像
//        测试所用操作系统： Windows 7 64bit
//        测试所用IDE版本：Visual Studio 2010
//        测试所用OpenCV版本：    2.4.9
//        2014年11月 Revised by @浅墨_毛星云
//------------------------------------------------------------------------------------------------
// Program to find smallest closed contour in image encosing a clicked point
// Author: Samarth Manoj Brahmbhatt, University of Pennsylvania


//---------------------------------【头文件、命名空间包含部分】----------------------------
//        描述：包含程序所使用的头文件和命名空间
//------------------------------------------------------------------------------------------------
#include <opencv2/opencv.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <iostream>
using namespace std;
using namespace cv;

//-----------------------------------【全局变量声明部分】---------------------------------------
//        描述：声明全局变量
//---------------------------------------------------------------------------------------------------
vector<vector<Point> > contours;
vector<Vec4i> heirarchy;
Mat img_all_contours;


//--------------------------【make_contours_closed( )函数】----------------------------
//         描述：Function to make the contours closed
//----------------------------------------------------------------------------------------------
void make_contours_closed(vector<vector<Point> > contours) {
    for(int i = 0; i < contours.size(); i++) {
        vector<Point> cc;
        approxPolyDP(contours[i], cc, 0.1, true);
        contours[i] = cc;
    }
}


//--------------------------【smallest_contour( )函数】-----------------------------------
//         描述：Function to find the index of smalledst enclosing contour in 'contours'
//----------------------------------------------------------------------------------------------
int smallest_contour(Point p, vector<vector<Point> > contours, vector<Vec4i> heirarchy) {
    int idx = 0, prev_idx = -1;
    while(idx >= 0) {
        vector<Point> c = contours[idx];
        // Point polygon test
        double d = pointPolygonTest(c, p, false);
        // If point is inside the contour, move to its child...
        if(d > 0) {
            prev_idx = idx;
            idx = heirarchy[idx][2];
        }
        //...else check the next cotour at the same level
        else idx = heirarchy[idx][0];
    }
    
    return prev_idx;
}

//--------------------------------------【on_mouse( )函数】-------------------------------
//         描述：鼠标回调函数
//----------------------------------------------------------------------------------------------
void on_mouse(int event, int x, int y, int, void *) {
    if(event != EVENT_LBUTTONDOWN) return;
    Point p(x, y);
    
    int idx = smallest_contour(p, contours, heirarchy);
    
    // If function returned a valid contour index, draw it using a thick red line
    if(idx > 0) {
        vector<vector<Point> > contour_show(1, contours[idx]);
        Mat img_show = img_all_contours.clone();
        drawContours(img_show, contour_show, -1, Scalar(0, 0, 255), 3);
        imshow("Contours", img_show);
    }
    else
        imshow("Contours", img_all_contours);
}


//-----------------------------------【main( )函数】--------------------------------------------
//        描述：控制台应用程序的入口函数，我们的程序从这里开始
//-------------------------------------------------------------------------------------------------
int main() {
    Mat img = imread("/Users/wangshiqi/Pictures/1.jpg");
    imshow("原始图",img);
    
    Mat edges;
    Canny(img, edges, 50, 100);
    findContours(edges, contours, heirarchy, RETR_TREE, CHAIN_APPROX_NONE);
    // Make the contours closed
    make_contours_closed(contours);
    img_all_contours = img.clone();
    // Draw all contours using a thin green line
    drawContours(img_all_contours, contours, -1, Scalar(0, 255, 0));
    
    namedWindow("Contours", WINDOW_AUTOSIZE);
    imshow("Contours", img_all_contours);
    
    setMouseCallback("Contours", on_mouse);
    
    while(char(waitKey(1)) != 'q') {}
    
    return 0;
}