基本形状的绘制+放置文字+随机线条

一、基本形状的绘制

基本形状主要包括画直线、矩形、椭圆、圆和多边形+文字.

实现代码如下：

#include<opencv2/opencv.hpp>
#include<iostream>
using namespace std;
using namespace cv;
Mat bgImage;
const char* drawdemo_win = "draw shapes and text demo";

void myLines();
void myRectangle();
void myEllipse();
void myCircle();
void myPolygon();

int main(int argv,char** argc){
	bgImage = imread("../../lena.jpg");
	if (bgImage.empty()) {
		printf("could not load image...");
		return -1;
	}
	//画线
	myLines();
	//矩形
	myRectangle();
	//椭圆
	myEllipse();
	//画圆
	myCircle();
	//多边形
	myPolygon();
	//文字
	putText(bgImage, "Hello OpenCV", Point(200, 200), CV_FONT_HERSHEY_COMPLEX, 1, Scalar(12, 255, 200), 1, 8);
	imshow(drawdemo_win, bgImage);
	waitKey(0);
	return 0;
}
void myLines() {
	Point p1 = Point(0,0);
	Point p2;
	p2.x = 512;
	p2.y = 512;
	Scalar color = Scalar(255, 255, 255);
	//line(图像，点1，点2，颜色，线宽，默认是LINE_8)
	line(bgImage, p1, p2, color, 1, LINE_8);
}
void myRectangle() {
	//Rect的参数可以前两个是矩形的左上角点，然后后面两个依次是宽度和长度
	Rect rect = Rect(230, 230, 130, 160);
	Scalar color = Scalar(255,0, 255);
	rectangle(bgImage, rect, color, 2, LINE_8);
}
void myEllipse() {
	Scalar color = Scalar(0, 255, 0);
	ellipse(bgImage, Point(bgImage.cols / 2, bgImage.rows / 2), Size(bgImage.cols / 4, bgImage.rows / 8), 135, 0,360, color, 2, LINE_8);
}
void myCircle() {
	Scalar color = Scalar(0,255,255);
	Point center = Point(bgImage.cols / 2, bgImage.rows / 2);
	//可以直接使用150半径，2表示线宽，8表示LINE_8
	circle(bgImage, center, 150, color, 2, 8);
}
void myPolygon() {
	//定义一个二维点
	Point pts[1][5];
	//多边形的绘制需要一个封闭的区域
	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, 12, 255);
	fillPoly(bgImage, ppts, npt, 1, color, 8);
}

输出：

二、随即线条绘制

实现代码：

#include<opencv2/opencv.hpp>
#include<iostream>
using namespace std;
using namespace cv;

void myRandomLineDemo();

Mat bgImage;
int main(int argv, char** argc) {
	bgImage = imread("../../lena.jpg");
	if (bgImage.empty()) {
		printf("could not load image...");
		return -1;
	}
	myRandomLineDemo();
	waitKey(0);
	return 0;
}
void myRandomLineDemo() {
	Mat bg = Mat::zeros(bgImage.size(), bgImage.type());
	RNG rng(12345);//随机数种子
	Point pt1, pt2;
	for (int i = 0; i < 10000; i++) {
		//rng.uniform(a,b)表示产生均匀分布的随机数，范围在[a，b)的随机数
		pt1.x = rng.uniform(0, bg.cols);
		pt2.x = rng.uniform(0, bg.cols);
		pt1.y = rng.uniform(0, bg.rows);
		pt2.y = rng.uniform(0, bg.rows);
		Scalar color = Scalar(rng.uniform(0, 255), rng.uniform(0, 255), rng.uniform(0, 255));
		if (waitKey(50) > 0) {
			break;
		}
		line(bg, pt1, pt2, color, 1, 8);
		imshow("random line demo", bg);
	}
}

 输出结果：