OpenCV绘制箭头

短命女 2022-08-14 05:42 230阅读 0赞

转载自：[http://tmjfzy.blog.163.com/blog/static/664470252012225101017794/][http_tmjfzy.blog.163.com_blog_static_664470252012225101017794]

代码：

#include "opencv2/core/core.hpp"
    #include "opencv2/highgui/highgui.hpp"
    #include "opencv2/imgproc/imgproc.hpp"
    using namespace cv;
    
    void drawArrow(cv::Mat& img, cv::Point pStart, cv::Point pEnd, int len, int alpha,
        cv::Scalar& color, int thickness = 1, int lintType = 8);
    
    int main(int argc, char** argv)
    {
        cv::Mat mat = imread("test.jpg");
        namedWindow("test");
        imshow("test", mat);
    
        Mat m(400, 400, CV_8UC3, Scalar(0, 0, 0));
        Point pStart(380, 100), pEnd(100, 250);
        Scalar lineColor(0, 255, 255);
        drawArrow(m, pStart, pEnd, 10, 45, lineColor);
        pStart = Point(100, 100);
        pEnd = Point(320, 190);
        lineColor = Scalar(0, 0, 255);
        drawArrow(m, pStart, pEnd, 25, 30, lineColor, 2, CV_AA);
        pStart = Point(200, 420);
        pEnd = Point(370, 170);
        lineColor = Scalar(255, 0, 255);
        drawArrow(m, pStart, pEnd, 17, 15, lineColor, 1, 4);
        imshow("draw arrow", m);
    
        waitKey();
        return 0;
    }
    
    
    void drawArrow(cv::Mat& img, cv::Point pStart, cv::Point pEnd, int len, int alpha, cv::Scalar& color, int thickness, int lineType)
    {
        const double PI = 3.1415926;
        Point arrow;
        //计算 θ 角（最简单的一种情况在下面图示中已经展示，关键在于 atan2 函数，详情见下面） 
        double angle = atan2((double)(pStart.y - pEnd.y), (double)(pStart.x - pEnd.x));
    
        line(img, pStart, pEnd, color, thickness, lineType);
    
        //计算箭角边的另一端的端点位置（上面的还是下面的要看箭头的指向，也就是pStart和pEnd的位置） 
        arrow.x = pEnd.x + len * cos(angle + PI * alpha / 180);
    
        arrow.y = pEnd.y + len * sin(angle + PI * alpha / 180);
    
        line(img, pEnd, arrow, color, thickness, lineType);
    
        arrow.x = pEnd.x + len * cos(angle - PI * alpha / 180);
    
        arrow.y = pEnd.y + len * sin(angle - PI * alpha / 180);
    
        line(img, pEnd, arrow, color, thickness, lineType);
    }

结果  
![这里写图片描述][20151124114257654]

[http_tmjfzy.blog.163.com_blog_static_664470252012225101017794]: http://tmjfzy.blog.163.com/blog/static/664470252012225101017794/
[20151124114257654]: /images/20220731/a57c5fe7dd4144009ca4a63147d1eae8.png