OpenCV Rect_< _Tp > 模版类是一个2维矩形模板类，其英文全称为Rect_< _Tp > Class Template Reference，其公有成员函数有以下几个：

        其公有属性有：

        Rect_< _Tp > 模版类以左上角点tl，坐标_Tp x,Tp y及矩形宽度及矩形高度来描述一个矩形。有了矩形的基本属性，就可获得其他属性。如右下角点br（用两点构造一个矩形，默认这两个点是其对角点），矩形的size，矩形的面积等，也可判定一个点是否在矩形内。另外矩形还可以执行一下操作：

        rect = rect ± point；//将矩形移动一定的偏移量

        rect = rect ±s ize；//将矩形扩大或缩小一定量

        rect += point；

        rect -= point；

        rect += size；

        rect -= size ；

        rect = rect1 & rect2；//求矩形相交部分(即相互叠加部分)

        rect = rect1 | rect2;  //同时包含 rect1 和 rect2 的最小面积矩形

        rect &= rect1,;

        rect |= rect1;

        bool b1 = (rect1 == rect2); //比较判断

        bool b2 = (rect1 != rect2); //比较判断

        因C++的基本数据类型有:int,flot,double等，OpenCV中有定义相应的Rect，如下：

        typedef Rect_<int> cv::Rect2i

        typedef Rect2i ​​​​​​cv::Rect

        typedef Rect_<double> cv::Rect2d

        typedef Rect_<float> cv::Rect2f

        常用的Rect实际上是矩形模板类实例化int的类。

        示例程序

        下面新建一个控制台应用程序，来演示矩形创建及其他成员函数的用法。其代码如下：

#include <iostream>
#include <opencv2/opencv.hpp>

using namespace cv;
using namespace std;

int main()
{
    Rect rec[8];
    Point pts[3];
    pts[0].x = 30;
    pts[0].y = 30;
    pts[1].x = 230;
    pts[1].y = 130;
    pts[2].x = 80;
    pts[2].y = 80;

    rec[1] = Rect(pts[0], Size(150, 100));//test constructor and "= "operatror
    rec[2] = Rect(80,80, 150,80);         //test constructor and" = "operatror
    rec[3] = Rect(pts[2], pts[1]);        //ttest constructor and" = "operatror

    cout << "rec[1] width = " << rec[1].width << endl;
    cout << "rec[1] height = " << rec[1].height << endl;
    cout << "rec[1] area = " << rec[1].area() << endl;
    cout << "rec[1] top left corner: " << rec[1].tl() << endl;
    cout << "rec[1] bottom left corner: " << rec[1].br() << endl;

    if (rec[1].contains(pts[2])) //test contiains function
        cout << "rec[1] contins pts[2] " << endl;
    else
    {
        cout << "rec[1] does not contin pts[2] " << endl;

    }
    rec[4] = rec[1] & rec[2]; //test" &" operater
    if (rec[4].empty())
        cout << " There is not intersection between rec[1] and rec[2]" << endl;
    else
    {
        cout << "rec[4] width = " << rec[4].width << endl;
        cout << "rec[4] height = " << rec[4].height << endl;
        cout << "rec[4] area = " << rec[4].area() << endl;
        cout << "rec[4] top left corner: " << rec[4].tl() << endl;
        cout << "rec[4] bottom left corner: " << rec[4].br() << endl;
    }
    rec[5] = rec[1] | rec[2]; // test "|" operater
    if (rec[5].empty())
        cout << "rec[5] is empty" << endl;
    else
    {
        cout << "rec[5] width = " << rec[5].width << endl;
        cout << "rec[5] height = " << rec[5].height << endl;
        cout << "rec[5] area = " << rec[5].area() << endl;
        cout << "rec[5] top left corner: " << rec[5].tl() << endl;
        cout << "rec[5] bottom left corner: " << rec[5].br() << endl;
    }

    rec[6] = rec[1] + Size(100, 100);
    cout << "rec[6] width = " << rec[6].width << endl;
    cout << "rec[6] height = " << rec[6].height << endl;
    cout << "rec[6] area = " << rec[6].area() << endl;
    cout << "rec[6] top left corner: " << rec[6].tl() << endl;
    cout << "rec[6] bottom left corner: " << rec[6].br() << endl;

    rec[7] = rec[1] + Point(50,50);
    cout << "rec[7] width = " << rec[7].width << endl;
    cout << "rec[7] height = " << rec[7].height << endl;
    cout << "rec[7] area = " << rec[7].area() << endl;
    cout << "rec[7] top left corner: " << rec[7].tl() << endl;
    cout << "rec[7] bottom left corner: " << rec[7].br() << endl;

    waitKey(0);
}

本博文到此结束。