（10）绘制形状和文字

基本代码，这个我自己没有实验

#include "../common/common.hpp"

    static Mat bgImage;
    static void drawLines();
    static void drawRectangle();
    static void drawEllipse();
    static void drawCircle();
    static void drawPolygon();
    static void drawRandomLine();

    void main1_8(int argc, char** argv)
    {
        bgImage = imread(getCVImagesPath("images/test1.png"), IMREAD_COLOR);
        drawLines();
        drawRectangle();
        drawEllipse();
        drawCircle();
        drawPolygon();
        //参数：Mat，文字(不识别中文?)，文字的位置(锚点?)，字体，缩放，颜色，线宽，线类型
        putText(bgImage, "Hello OpenCV", Point(0, 200), CV_FONT_HERSHEY_COMPLEX, 1.0, Scalar(0), 3, LINE_8);//绘制文字
        imshow("src", bgImage);

        drawRandomLine();

        waitKey(0);
    }

    void drawLines()//绘制线条
    {
        Point p1 = Point(20, 30);//Point表示平面上的点，OpenCV中的这些坐标值都是相对于图像本身像素值的
        Point p2;
        p2.x = 400;
        p2.y = 400;
        Scalar color = Scalar(0, 0, 255);
        line(bgImage, p1, p2, color, 10, LINE_AA);//绘制线条到Mat，10是线宽、LINE_4或LINE_8是带锯齿的，LINE_AA是抗锯齿的
    }

    void drawRectangle()//绘制矩形
    {
        //OpenCV的坐标系，原点在屏幕左上角，x朝右正，y朝下正
        Rect rect = Rect(200, 100, 300, 300);//起始位置x、y，宽，高
        Scalar color = Scalar(255, 0, 0);
        rectangle(bgImage, rect, color, LINE_8);//绘制矩形到Mat，自带圆角。。
    }

    void drawEllipse()//绘制椭圆
    {
        int width = bgImage.cols;
        int height = bgImage.rows;
        Scalar color = Scalar(0, 255, 0);
        //绘制椭圆，参数：Mat，中心点，椭圆的长短轴半径，椭圆的朝向(0表示水平)，起始角度，终点角度
        ellipse(bgImage, Point(width / 2, height / 2), Size(width / 4, height / 8), 0, 0, 270, color, 2, LINE_8);
    }

    void drawCircle()//绘制圆
    {
        Scalar color = Scalar(0, 255, 255);
        circle(bgImage, Point(bgImage.cols / 2, bgImage.rows / 2), 150, color, 2, LINE_8);
    }

    void drawPolygon()//绘制多边形，绘制的多边形是填充的
    {
        Point pts[1][5];
        pts[0][0] = Point(100, 100);
        pts[0][1] = Point(100, 200);
        pts[0][2] = Point(200, 200);
        pts[0][3] = Point(200, 100);
        pts[0][4] = Point(100, 100);

        const Point * ppts[] = { pts[0] };
        int npt[] = { 5 };
        Scalar color = Scalar(255, 0, 255);
        //参数：Mat，顶点数据指针，顶点个数，1表示只绘制一个contour(轮廓)
        fillPoly(bgImage, ppts, npt, 1, color, LINE_8);
    }

    void drawRandomLine()//循环绘制随机位置随机颜色的线段
    {
        Mat randomLineMat = Mat::zeros(bgImage.size(), bgImage.type());
        RNG rng(12345);//生成高斯随机数，参数种子
        Point p1, p2;
        for (int i = 0; i < 100000; i++)
        {
            p1.x = rng.uniform(0, randomLineMat.cols);//生成正态分布 0-bgImage.cols 范围内的随机数
            p1.y = rng.uniform(0, randomLineMat.rows);
            p2.x = rng.uniform(0, randomLineMat.cols);
            p2.y = rng.uniform(0, randomLineMat.rows);
            Scalar color = Scalar(rng.uniform(0, 255), rng.uniform(0, 255), rng.uniform(0, 255));
            if (waitKey(50) > 0)//参数delay如果传0表示阻塞等待键盘事件，传大于0表示只阻塞等待delay毫秒，键盘无响应返回-1
            {
                break;
            }
            line(randomLineMat, p1, p2, color, 1, LINE_8);
            imshow("randomLine", randomLineMat);
        }
    }