Opencv3 C++ VS2017 study notes 06 draw shapes and text with random lines

• The cv::Point class represents the point x, y on the 2D plane
  • Attributes x and y
  • 即Point p;  p.y=9; p.x=1;
• The cv::Scalar class represents a vector of four elements
  • Scalar(b,g,r); represents the value of the three channels of bgr, which can represent color
• Draw line cv::line()
  • line() parameters: 
    • LINE_4  
    • LINE_8
    • LINE_AA zigzag line
    • line(src0, p1, p2, color, 1, LINE_8, 0); //Parameters: background image, start point, end point, line color, thickness line thickness, line type LINE_8
• Draw an ellipse cv::ellipse()
  • ellipse(src0, Point(src0.cols/2, src0.rows/2), Size(src0.cols/4, src0.rows/8),90, 0 ,360, color, LINE_8);  
  •   Parameters: background image, center of ellipse, length and radius of ellipse, direction of ellipse lying, starting angle, color, line type
• Draw rectangle cv::rectangle() 
  • Create a rectangular object
    • Rect rect = Rect(200, 100, 300, 300); //Parameter: left vertex coordinates x, y and width\height 
  • rectangle(src0, rect, color, 1, LINE_8); //Parameters: background image, rectangle object, color, thickness, line type
• Draw a circle cv::circle()
  • circle(src0, center, radius, color, 1, LINE_8);  //
  • Parameters: background image, center, radius, color, thickness, line type
• Fill cv::fillPoly()
• Fill text putText() 
  • putText(src0, "hello", Point(src0.cols / 2, src0.rows / 2), FONT_HERSHEY_COMPLEX, 2, Scalar(122, 222, 31), 1, LINE_8);
  • Parameters: background image, text content, cursor starting point, font style, font size, color, thickness, line type
• Draw lines randomly
• RNG type, random number generation
  • RNG rng(seed);
  • rng.uniform(double a, double b); The uniform function is used to determine the generation limit

#include "pch.h"
#include <iostream>
#include <opencv2/opencv.hpp>
#include <string>

using namespace std;
using namespace cv; 

void MyLines();
void MyRectangle();
void Myellipse();
void MyCircle();
void RandomDemo();
Mat src0, src1;

int main(int argc, char ** argv)
{
	src0 = imread("C:\\Users\\xujin\\Desktop\\test0.JPG");
	if (!src0.data)
	{
		cout << "no image";
		return -1;
	}
	MyLines();
	MyRectangle();
	Myellipse();
	MyCircle();
	putText(src0, "hello", Point(src0.cols / 2, src0.rows / 2), FONT_HERSHEY_COMPLEX, 2, Scalar(122, 222, 31), 1, LINE_8);
	//参数:背景图, 文本内容, 光标起点, 字形,字体大小, 颜色, thickness,线型
	namedWindow("src0_image", WINDOW_AUTOSIZE);
	imshow("src0_image", src0);
	RandomDemo();
	waitKey(0);
	return 0;
}

void MyLines()
{
	Point p1 = Point(20, 30);
	Point p2;
	Scalar color = Scalar(0, 0, 255);
	p2.x = 300;
	p2.y = 300;
	line(src0, p1, p2, color, 1, LINE_8, 0);    //参数: 背景图,开始点,结束点, 线条颜色, thickness线条厚度, 线条类型LINE_8

}
void MyRectangle()
{
	Rect rect = Rect(200, 100, 300, 300);       //参数:左顶点坐标x,y和width\height
	Scalar color = Scalar(233, 1, 22);				
	rectangle(src0, rect, color, 1, LINE_8);			//参数:背景图,矩形对象, 颜色, thickness, 线型

}

void Myellipse()
{
	Scalar color = Scalar(0, 222, 31);
	ellipse(src0, Point(src0.cols/2, src0.rows/2), Size(src0.cols/4, src0.rows/8),90, 0 ,360, color, LINE_8);  
	//参数: 背景图, 椭圆中心,椭圆的长短半径, 椭圆躺着的方向, 起始角度,颜色,线型
}

void MyCircle()
{
	Scalar color = Scalar(0, 222, 31);
	Point center = Point(src0.cols / 2, src0.rows / 2);
	int radius = 140;
	circle(src0, center, radius, color, 1, LINE_8);  //参数: 背景图, 圆心, 半径, 颜色, thickness, 线型

}

void RandomDemo()
{
	RNG rng(12345);
	Point p1;
	Point p2;
	Mat bg = Mat::zeros(src0.size(), src0.type());
	namedWindow("bg_image", WINDOW_AUTOSIZE);
	for (int i = 0; i < 100000; i++)
	{
		p1.x = rng.uniform(0, src0.cols);
		p2.x = rng.uniform(0, src0.cols);
		p1.y = rng.uniform(0, src0.rows);
		p2.y = rng.uniform(0, src0.rows);
		Scalar color = Scalar(rng.uniform(0, 255), rng.uniform(0, 255), rng.uniform(0, 255));
		line(bg, p1, p2, color, 1, LINE_8);
		imshow("bg_image", bg);
		if (waitKey(50) > 0)
		{
			break;
		}
	}
	
}