OPENCV学习笔记1-6_图像上绘图

1.1 Related Class

　　1. Class: OpenCV::CvPoint
　　CvPoint：表示一个坐标为整数的二维点，是一个包含integer类型成员x和y的结构体。

typdef struct CvPoint {
int x;         // X axis
int y;         // Y axis
}

　2. Class: OpenCV::CvScalar
 　　CvScalar是一个包含四个元素的结构体变量。Element-value （元素）of one pixel. OpenCV supports the image of 4-channels in the maximum. Therefore, CvScalar has 4-values。

typdef struct CvScalar {
double val[4];
} CvScalar;

1.2 Sample code  

#include <iostream>
#include <opencv2/opencv.hpp>            //含了OpenCV中各个模块的头文件 must or not able used circle
//#include <opencv2/core/core.hpp>
//#include <opencv2/highgui/highgui.hpp>

using namespace cv;
using namespace std;

#define  height 480
#define  width  600

CvPoint CircleCenter;
int Radius;
CvScalar Color;
int Thickness;
int Shift;

int main()
{

Mat image(height, width, CV_8UC3, Scalar(255, 255, 255));//(255, 255, 255); white (0, 0, 0) black
CircleCenter = cvPoint(100, 100);
Radius = 50;
Color = CV_RGB(255, 0, 0);
Thickness = 3;
Shift = 0;

circle(image, CircleCenter, Radius, Color, Thickness, Shift);

putText(image,                  // destination image
"This is a circle.",        // text
Point(40, 200),             // text position
FONT_HERSHEY_PLAIN,         // font type
2.0,                        // font scale
255,                        // text color (here white)
2);                         // text thickness
namedWindow("yunfung image", WINDOW_NORMAL);
imshow("yunfung image", image);

waitKey(0);
return 0;
}