【OpenCV入门之十五】随心所欲绘制想要形状

void cvCircle( CvArr* img, CvPoint center, int radius, CvScalar color,int thickness=1, int line_type=8, int shift=0 );

#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include <iostream>
#include <stdio.h>

using namespace std;
using namespace cv;

//画圆画点都是使用circle()函数来画，点就是圆，我们平常所说的圆只不过是半径大一点而已。
int main()
{
    Mat img = imread("lol16.jpg");  

    //画空心点
    Point p(20, 20);//初始化点坐标为(20,20)
    circle(img, p, 2, Scalar(0, 255, 0)); //第三个参数表示点的半径，第四个参数选择颜色。这样子我们就画出了绿色的空心点

    //这种初始化点的方式也可以
    Point p2;
    p2.x = 100;
    p2.y = 100;
    //画实心点
    circle(img, p2, 3,Scalar(255,0,0),-1); //第五个参数我设为-1，表明这是个实点。

    //画空心圆
    Point p3(300, 300);
    circle(img,p3,100,Scalar(0,0,255),3);//第五个参数我们调高点，让线更粗

    //画实心圆
    Point p4;
    p4.x = 600;
    p4.y = 600;
    circle(img, p4, 100, Scalar(120, 120, 120), - 1);

    imshow("画点画圆", img);

    waitKey();
    return 0;
}

void ellipse(Mat& img, Point center,Size axes, double angle, double startAngle, double endAngle, const Scalar& color,int thickness=1, int lineType=8, int shift=0)

void rectangle(Mat& img,Rect rec, const Scalar&color, intthickness=1, intlineType=8,intshift=0 )

void line(InputOutputArray img, Point pt1, Point pt2, const Scalar& color,int thickness = 1, int lineType = LINE_8, int shift = 0);

#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include <iostream>
#include <stdio.h>

using namespace std;
using namespace cv;

int main()
{
    Mat img = imread("lol16.jpg");  
    Point p1(100, 100);
    Point p2(758, 50);
    line(img, p1, p2, Scalar(33, 33, 133), 2);

    //画第二条线
    line(img, Point(300, 300), Point(758, 300), Scalar(89, 90, 90), 3);

    imshow("画矩形", img);

    waitKey();
    return 0;
}

void cv::putText(cv::Mat& img, const string& text,cv::Point origin,   int fontFace,double fontScale,  cv::Scalar color,int thickness = 1,int lineType = 8, bool bottomLeftOrigin = false );

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

using namespace std;
using namespace cv;

Mat src;
void drawLines();
void drawRectangle();
void drawEllipse();
void drawCircle();
void drawPolygon();
void drawRandomLine();
void drawText();

int main(int argc,char** argv){
  //创建空白图用于绘制图形
  src=Mat::zeros(Size(500,500),CV_8UC3);
  //设置蓝色背景
  src.setTo(cv::Scalar(100, 0, 0));

  //调用函数
  drawLines();
  drawRectangle();
  drawEllipse();
  drawCircle();
  drawPolygon();
  drawText();
  drawRandomLine();

  imshow("input Image",src);

  waitKey(0);
  return 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 = 300;
  p2.y = 300;
  Scalar color = Scalar(0,0,255);
  line(src, p1, p2, color, 1, LINE_AA);//绘制线条到Mat，1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, 200, 250);//起始位置x、y，宽，高
  Scalar color = Scalar(255, 0, 0);
  rectangle(src, rect, color, 2, LINE_8);//绘制矩形到Mat，自带圆角
}


void drawEllipse(){//绘制椭圆
  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(src, Point(src.cols/2,src.rows/2), Size(src.cols/8,src.rows/4), 90, 0, 360, color, 1, LINE_8);
}


void drawCircle(){//绘制圆
  Scalar color = Scalar(0, 255, 255);
  circle(src, Point(src.cols / 2, src.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(src, ppts, npt, 1, color, LINE_8);
}

void drawText(){
  //设置绘制文本的相关参数
  std::string text = "Hello OpenCV!";
  int font_face = cv::FONT_HERSHEY_COMPLEX; 
  double font_scale = 2;
  int thickness = 2;
  int baseline;
  //获取文本框的长宽
  cv::Size text_size = cv::getTextSize(text, font_face, font_scale, thickness, &baseline);
 
  //将文本框居中绘制
  Point origin; 
  origin.x = src.cols / 2 - text_size.width / 2;
  origin.y = src.rows / 2 + text_size.height / 2;
  putText(src, text, origin, font_face, font_scale, cv::Scalar(0, 255, 255), thickness, 8, 0);
 
  //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(src, "Hello OpenCV", Point(0, 200), CV_FONT_HERSHEY_COMPLEX, 1.0, Scalar(0), 3, LINE_8);//绘制文字

  //显示绘制解果
  //cv::imshow("image", src);
}


void drawRandomLine()//循环绘制随机位置随机颜色的线段
{
    Mat randomLineMat = Mat::zeros(src.size(), src.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);
    }
}