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前言

opencv绘制形状与文字

一、绘制形状与文字的模板类：

1、Point模板类（二维）：

解析：为了描述图像中的点，opencv提供了由坐标“x”和“y”指定的 二维点 的模板类,该类的一个实例可以与C结构、CvPoint和CvPoint2D32f互换。有也是一个cast操作符，用于将点坐标转换为指定类型。从通过舍入将浮点坐标转换为整数坐标。通常，转换对每个坐标使用此操作

pt1 = pt2 + pt3;    pt1 = pt2 - pt3;    pt1 = pt2 * a;    pt1 = a * pt2;    pt1 = pt2 / a;    pt1 += pt2;    pt1 -= pt2;    pt1 *= a;    pt1 /= a;    double value = norm(pt); // L2 norm    pt1 == pt2;    pt1 != pt2;

为方便起见，定义了以下类型别名:

typedef Point_
   
     Point2i;    typedef Point2i Point;    typedef Point_
    
      Point2f;    typedef Point_
     
       Point2d;举例：	Point2f a(0.3f, 0.f), b(0.f, 0.4f);    Point pt = (a + b)*10.f;    cout << pt.x << ", " << pt.y << endl;
     
    
   

三维的点坐标，我们可以自行学习：

2、Scalar向量模板类：

解析：从Vec派生的4元素向量的模板类，从Vec\<_Tp, 4\> , Scalar\_ 和 Scalar派生而来，可以像典型的4元素一样使用向量。此外，还可以将它们转换为CvScalar。OpenCV传递像素值。

//进行实例化，直接使用color使用创建的像素值Scalar color = Scalar(0, 150, 15);

3、Rect二维矩阵模板类：

解析：二维矩形的简明模板类；左上角的坐标开始，构建一个矩阵

//构造函数： 	Rect_();    Rect_(_Tp _x, _Tp _y, _Tp _width, _Tp _height);    Rect_(const Rect_& r);    Rect_(Rect_&& r) CV_NOEXCEPT;    Rect_(const Point_<_Tp>& org, const Size_<_Tp>& sz);    Rect_(const Point_<_Tp>& pt1, const Point_<_Tp>& pt2);//参数：	_Tp x；//左上角的x坐标	_Tp y；//左上角的y坐标	_Tp width；//矩形的宽度	_Tp height；//矩形的高度

矩形的其他操作：

-\f$\texttt{   rect} = \texttt{   rect} \pm \texttt{   point}\f$ （将矩形移动一定的偏移量）-\f$\texttt{   rect} = \texttt{   rect} \pm \texttt{   size}\f$ 通过一定数量）-rect+=point，rect-=point，rect+=size，rect-=size（增广运算）-rect=rect1&rect2（矩形相交）-rect=rect1 | rect2（包含rect1和rect2的最小面积矩形）-rect&=rect1，rect |=rect1（及相应的增广运算）-rect==rect1，rect！=rect1（矩形比较）

4、RNG类

解析：第一个窗体将状态设置为预定义值，在当前实现中等于2\*\*32-1。这个第二种形式将状态设置为指定值。如果通过state=0，构造函数使用上述默认值来避免奇异随机数序列，由全零组成。

构造函数：

RNG();    /** @overload    @param state 64-bit value used to initialize the RNG.    */    RNG(uint64 state);

uniform()方法：

int uniform(int a, int b);    /** @overload */    float uniform(float a, float b);    /** @overload */    double uniform(double a, double b);//返回[a，b）范围内均匀分布的整数随机数这些方法使用MWC算法进行状态转换，//并返回下一个指定类型的均匀布随机数从输入参数类型，从范围[a，b]。

二、绘制形状与文字的函数：

1、line()函数：

简而言之：绘制从第一个点指向第二个点的箭头段。

void line(InputOutputArray img, Point pt1, Point pt2, const Scalar& color,                     int thickness = 1, int lineType = LINE_8, int shift = 0);/*img 图像.pt1 pt1箭头的起始点.pt2 pt2箭头指向的点.color 线条颜色.thickness 线条厚度.line_type line的类型. shift Number of fractional bits in the point coordinates.点坐标中小数位数的移位tipLength 相对于箭头长度的箭头尖端长度*/

line()函数线的类型：

enum LineTypes {       FILLED  = -1,    LINE_4  = 4, //!< 4-connected line    LINE_8  = 8, //!< 8-connected line    LINE_AA = 16 //!< antialiased line抗锯齿};

2、rectangle()函数：

简而言之：绘制简单的、粗的或填充的右矩形。rectangle绘制一个矩形轮廓或两个对角的填充矩形是pt1和pt2。

CV_EXPORTS_W void rectangle(InputOutputArray img, Point pt1, Point pt2,                          const Scalar& color, int thickness = 1,                          int lineType = LINE_8, int shift = 0);/*use `rec` parameter as alternative specification of the drawn rectangle: `r.tl() andr.br()-Point(1,1)` are opposite corners*/CV_EXPORTS_W void rectangle(InputOutputArray img, Rect rec,                          const Scalar& color, int thickness = 1,                          int lineType = LINE_8, int shift = 0);/** @example samples/cpp/tutorial_code/ImgProc/basic_drawing/Drawing_2.cppAn example using drawing functions*/

3、ellipse()函数：

简而言之，绘制简单或粗的椭圆弧或填充椭圆扇区。eliple绘制椭圆轮廓、填充椭圆和椭圆，圆弧或实心椭圆扇形。采用分段线性曲线逼近椭圆弧边界。

CV_EXPORTS_W void ellipse(InputOutputArray img, Point center, Size axes,                        double angle, double startAngle, double endAngle,                        const Scalar& color, int thickness = 1,                        int lineType = LINE_8, int shift = 0);CV_EXPORTS_W void ellipse(InputOutputArray img, const RotatedRect& box, const Scalar& color,                        int thickness = 1, int lineType = LINE_8);

4、circle()函数：

简而言之：画了一个圆。circle用给定的圆心和半径绘制一个简单的或填充的圆。

CV_EXPORTS_W void circle(InputOutputArray img, Point center, int radius,                       const Scalar& color, int thickness = 1,                       int lineType = LINE_8, int shift = 0);

5、fillPoly()函数：

简而言之：填充凸多边形，fillconverxpoly绘制一个填充的凸多边形。这个函数比函数#fillPoly。它不仅可以填充凸多边形，而且可以填充任何单调多边形自相交，即轮廓与每条水平线（扫描线）相交的多边形最多两次（不过，其顶部和/或底部边缘可能是水平的）。

CV_EXPORTS void fillPoly(InputOutputArray img, const Point** pts,                         const int* npts, int ncontours,                         const Scalar& color, int lineType = LINE_8, int shift = 0,                         Point offset = Point() );

三、在图像上绘制形状和文字：

1、绘制线条：

代码块：

#include 
   
    #include 
    
     using namespace std;using namespace cv;Mat bgImage;const char* dravdemo_win = "draw shapes and text demo!!!";void Myline() {   	Point p1 = Point(0, 0);	Point p2;	p2.x = bgImage.cols;	p2.y = bgImage.rows;	Scalar color = Scalar(0, 0, 255);	line(bgImage, p1, p2, color, 1, LINE_4);}int main() {   	bgImage = imread("D:\\Myfile\\素材照片\\opencv素材照片\\4.jpg");	if (!bgImage.data) {   		cout << "could not load image..." << endl;		return 0;	}	Myline();	namedWindow(dravdemo_win, WINDOW_AUTOSIZE);	imshow(dravdemo_win, bgImage);		waitKey(0);	return 0;}
    
   

运行结果：

2、绘制矩形

代码块：

#include 
   
    #include 
    
     using namespace std;using namespace cv;Mat bgImage;const char* dravdemo_win = "draw shapes and text demo!!!";void MyRectangle() {   	Rect rect = Rect(66, 25, 73, 72);	Scalar color = Scalar(255, 0, 0);	rectangle(bgImage, rect, color, 2, LINE_8);	rect= Rect(142, 60, 55, 60);	color = Scalar(0, 255, 0);	rectangle(bgImage, rect, color, 2, LINE_8);	rect = Rect(210, 62, 55, 55);	color = Scalar(0, 0, 255);	rectangle(bgImage, rect, color, 2, LINE_8);}int main() {   	bgImage = imread("D:\\Myfile\\素材照片\\opencv素材照片\\8.jpg");	if (!bgImage.data) {   		cout << "could not load image..." << endl;		return 0;	}	MyRectangle();	namedWindow(dravdemo_win, WINDOW_AUTOSIZE);	imshow(dravdemo_win, bgImage);		waitKey(0);	return 0;}
    
   

运行结果：

3、绘制椭圆与圆

代码块：

#include 
   
    #include 
    
     using namespace std;using namespace cv;Mat bgImage;const char* dravdemo_win = "draw shapes and text demo!!!";void MyEllipse() {   	Scalar color = Scalar(0, 255, 255);	ellipse(bgImage, Point(bgImage.cols / 2, bgImage.rows / 2), Size(bgImage.cols / 4, bgImage.rows / 4), 90, 0, 360, color, 2, LINE_8);}void MyCircle() {   	Scalar color = Scalar(255, 0, 255);	circle(bgImage, Point(bgImage.cols / 2, bgImage.rows / 2), 30, color, 2, LINE_8);}int main() {   	bgImage = imread("D:\\Myfile\\素材照片\\opencv素材照片\\8.jpg");	if (!bgImage.data) {   		cout << "could not load image..." << endl;		return 0;	}	MyEllipse();	MyCircle();	namedWindow(dravdemo_win, WINDOW_AUTOSIZE);	imshow(dravdemo_win, bgImage);		waitKey(0);	return 0;}
    
   

运行结果：

4、绘制凸多边形

代码块：

#include 
   
    #include 
    
     using namespace std;using namespace cv;Mat bgImage;const char* dravdemo_win = "draw shapes and text demo!!!";void MyPolygon() {   	Point pts[1][5];	pts[0][0] = Point(10, 10);	pts[0][1] = Point(10, 40);	pts[0][2] = Point(200, 200);	pts[0][3] = Point(200, 10);	pts[0][4] = Point(10, 10);	const Point* ppts[] = {    pts[0] };	int npt[] = {    5 };	Scalar color = Scalar(0, 150, 15);	fillPoly(bgImage, ppts, npt, 1, color, 8);}int main() {   	bgImage = imread("D:\\Myfile\\素材照片\\opencv素材照片\\4.jpg");	if (!bgImage.data) {   		cout << "could not load image..." << endl;		return 0;	}	MyPolygon();	namedWindow(dravdemo_win, WINDOW_AUTOSIZE);	imshow(dravdemo_win, bgImage);		waitKey(0);	return 0;}
    
   

运行结果：

5、写文字

代码块：

#include 
   
    #include 
    
     using namespace std;using namespace cv;int main() {   	Mat bgImage;	const char* dravdemo_win = "draw shapes and text demo!!!";	bgImage = imread("D:\\Myfile\\素材照片\\opencv素材照片\\6.jpg");	if (!bgImage.data) {   		cout << "could not load image..." << endl;		return 0;	}	putText(bgImage, "Hello five-size-seven!", Point(10, 20), FONT_HERSHEY_DUPLEX, 1.0, Scalar(120, 255, 120), 1, 4);	namedWindow(dravdemo_win, WINDOW_AUTOSIZE);	namedWindow(dravdemo_win, WINDOW_AUTOSIZE);	imshow(dravdemo_win, bgImage);		waitKey(0);	return 0;}
    
   

运行结果：

6、绘制随机线条

代码块：

#include 
   
    #include 
    
     using namespace std;using namespace cv;Mat bgImage;const char* dravdemo_win = "draw shapes and text demo!!!";void RandomLineDemo() {   	RNG rng(12345);	Point pt1;	Point pt2;	namedWindow("Randow_new_image", WINDOW_AUTOSIZE);	Mat new_bgImage = Mat::zeros(bgImage.size(), bgImage.type());	for (int i = 0; i < 100000; i++) {   		pt1.x = rng.uniform(0, bgImage.cols);		pt2.x = rng.uniform(0, bgImage.cols);		pt1.y = rng.uniform(0, bgImage.rows);		pt2.y = rng.uniform(0, bgImage.rows);		Scalar color = Scalar(rng.uniform(0, 255), rng.uniform(0, 255), rng.uniform(0, 255));				if (waitKey(50) > 0)break;		line(new_bgImage, pt1, pt2, color, 1, 8);		imshow("Randow_new_image", new_bgImage);	}}int main() {   	bgImage = imread("D:\\Myfile\\素材照片\\opencv素材照片\\4.jpg");	if (!bgImage.data) {   		cout << "could not load image..." << endl;		return 0;	}	RandomLineDemo();	namedWindow(dravdemo_win, WINDOW_AUTOSIZE);	imshow(dravdemo_win, bgImage);		waitKey(0);	return 0;}
    
   

运行结果：

四、总代码块

#include 
   
    #include 
    
     using namespace std;using namespace cv;Mat bgImage;const char* dravdemo_win = "draw shapes and text demo!!!";void Myline() {   	Point p1 = Point(0, 0);	Point p2;	p2.x = bgImage.cols;	p2.y = bgImage.rows;	Scalar color = Scalar(0, 0, 255);	line(bgImage, p1, p2, color, 1, LINE_8);}void MyRectangle() {   	Rect rect = Rect(66, 25, 73, 72);	Scalar color = Scalar(255, 0, 0);	rectangle(bgImage, rect, color, 2, LINE_8);	rect= Rect(142, 60, 55, 60);	color = Scalar(0, 255, 0);	rectangle(bgImage, rect, color, 2, LINE_8);	rect = Rect(210, 62, 55, 55);	color = Scalar(0, 0, 255);	rectangle(bgImage, rect, color, 2, LINE_8);}void MyEllipse() {   	Scalar color = Scalar(0, 255, 255);	ellipse(bgImage, Point(bgImage.cols / 2, bgImage.rows / 2), Size(bgImage.cols / 4, bgImage.rows / 4), 90, 0, 360, color, 2, LINE_8);}void MyCircle() {   	Scalar color = Scalar(255, 0, 255);	circle(bgImage, Point(bgImage.cols / 2, bgImage.rows / 2), 30, color, 2, LINE_8);}void MyPolygon() {   	Point pts[1][5];	pts[0][0] = Point(10, 10);	pts[0][1] = Point(10, 40);	pts[0][2] = Point(20, 20);	pts[0][3] = Point(20, 10);	pts[0][4] = Point(10, 10);	const Point* ppts[] = {    pts[0] };	int npt[] = {    5 };	Scalar color = Scalar(0, 150, 15);	fillPoly(bgImage, ppts, npt, 1, color, 8);}void RandomLineDemo() {   	RNG rng(12345);	Point pt1;	Point pt2;	namedWindow("Randow_new_image", WINDOW_AUTOSIZE);	Mat new_bgImage = Mat::zeros(bgImage.size(), bgImage.type());	for (int i = 0; i < 100000; i++) {   		pt1.x = rng.uniform(0, bgImage.cols);		pt2.x = rng.uniform(0, bgImage.cols);		pt1.y = rng.uniform(0, bgImage.rows);		pt2.y = rng.uniform(0, bgImage.rows);		Scalar color = Scalar(rng.uniform(0, 255), rng.uniform(0, 255), rng.uniform(0, 255));				if (waitKey(50) > 0)break;		line(new_bgImage, pt1, pt2, color, 1, 8);		imshow("Randow_new_image", new_bgImage);	}}int main() {   	bgImage = imread("D:\\Myfile\\素材照片\\opencv素材照片\\8.jpg");	if (!bgImage.data) {   		cout << "could not load image..." << endl;		return 0;	}	Myline();	MyRectangle();	MyEllipse();	MyCircle();	MyPolygon();	//RandomLineDemo();	putText(bgImage, "Hello Opencv", Point(10, 20), FONT_HERSHEY_PLAIN, 1.0, Scalar(120, 120, 120), 1, 4);	namedWindow(dravdemo_win, WINDOW_AUTOSIZE);	namedWindow(dravdemo_win, WINDOW_AUTOSIZE);	imshow(dravdemo_win, bgImage);		waitKey(0);	return 0;}
    
   

运行结果：

总结

本文讲述了如何绘画形状和文字，已经创建随机线条

如有错误，敬请指正！