绘制点和圆
void cvCircle( CvArr* img, CvPoint center, int radius, CvScalar color,int thickness=1, int line_type=8, int shift=0 );
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。
#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;
}
绘制椭圆
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)
绘制矩形
void rectangle(Mat& img,Rect rec, const Scalar&color, intthickness=1, intlineType=8,intshift=0 )
绘制直线
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;
}
输出文字
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 );
最后给出一个完整的程序
#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);
}
}
运行结果
主要借鉴”Madcola“和”Micheal超“两位大神的文章。两位大神的博客主页是: https://www.cnblogs.com/skyfsm/(Madcola) https://blog.csdn.net/qq_42887760(Micheal超)