绘画功能

圆形

void circle(Mat &img, Point center, int radius, const Scalar &color,] int thickness=1,] int lineType=8,] int shift=0)

枚举类

lineType
8(默认) ———— 8连接线。
4 ———— 4连接线。
CV_AA ———— 抗锯齿线。

例子

circle(img, Point(100,100), 50, Scalar(100,0,100), 2); 中心(100,100)，半径50，线条颜色bgr(100,0,100)，线条厚度为2. 
circle1


circle(img, Point(100,100), 50, Scalar(100,0,100), -1); 中心(100,100)，半径50，实心，颜色bgr(100,0,100). 
circle2



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) void ellipse(Mat& img, const RotatedRect& box, const Scalar& color, ] int thickness=1, int lineType=8)

参数

img – 图片。
center – 椭圆的中心。
axes – 椭圆主轴尺寸的一半。(见下axes.width和axes.height)
angle – 椭圆旋转角度，以度为单位。(见下angle)
startAngle – 椭圆弧的起始角度，以度为单位。(见下startAngle)
endAngle – 椭圆弧的终止角度，以度为单位。(见下endAngle)
box – 通过RotatedRect或CvBox2D的替代椭圆表示。这意味着该函数绘制一个刻在旋转矩形中的椭圆。
color – 颜色。
thickness – 椭圆弧轮廓的厚度（如果为正）。 否则，这表明将绘制一个填充的椭圆扇形。
lineType – 椭圆边界的类型。
shift – 中心坐标和轴值中的小数位数。
ellipse

例子

ellipse(img, Point(100,100), Size(100,50), 30, 0, 270, Scalar(0, 103, 255), -1) 
ellipse



长方形

void rectangle(Mat &img, Point pt1, Point pt2, const Scalar &color, ] int thickness=1, int lineType=8, int shift=0) void rectangle(Mat &img, Rect rec, const Scalar &color, ] int thickness=1, int lineType=8, int shift=0)

例子

rectangle(img, Point(50,50), Point(150,150), Scalar(103, 255, 0), -1) 
rectangle


rectangle(img, Point(50,50), Point(150,150), Scalar(103, 255, 0), 5) 
rectangle



直线

void line(Mat &img, Point pt1, Point pt2, const Scalar &color, ] int thickness=1, int lineType=8, int shift=0)

例子

line(img, Point(50,50), Point(150,150), Scalar(103, 0, 255), 5) 
line



箭头

void arrowedLine(Mat& img, Point pt1, Point pt2, const Scalar& color, ] int thickness=1, int line_type=8, int shift=0, double tipLength=0.1)

参数

tipLength – 箭头笔尖相对于箭头长度的长度

例子

arrowedLine(img, Point(50,50), Point(150,150), Scalar(103, 0, 255), 5) 
arrowedline



文字

void putText(Mat &img, const string &text, Point org, int fontFace, double fontScale, Scalar color, int thickness=1, int lineType=8, bool bottomLeftOrigin=false )

参数

text – 要写入的文字。
org – 左下角的坐标。 
fontFace – 字体。为：FONT_HERSHEY_SIMPLEX, FONT_HERSHEY_PLAIN, FONT_HERSHEY_DUPLEX, 
                   FONT_HERSHEY_COMPLEX, FONT_HERSHEY_TRIPLEX, FONT_HERSHEY_COMPLEX_SMALL, 
                   FONT_HERSHEY_SCRIPT_SIMPLEX, or FONT_HERSHEY_SCRIPT_COMPLEX。
                   字体ID可以+FONT_ITALIC 来得到倾斜的字体。 
fontScale – 字体比例大小。 
bottomLeftOrigin – 为true时，图像数据源位于左下角。 否则，它位于左上角（如果true，字体将上下倒反）。

例子

putText(img, "Hello", Point(50,100), FONT_HERSHEY_SIMPLEX, 1, Scalar(255,103,0), 2) 
text
PutText仅支持英语字母，任何UTF是不支持的（包括汉字）



例子

例子(一)

draw_example_1.cpp #include <opencv2/opencv.hpp> using namespace cv; int main() { Mat img(300,300,CV_8UC3,Scalar(0)); //中心点 Point center = Point(img.cols/2,img.rows/2); //实心圆 circle(img,center, 7, Scalar(0,0,255),-1); //椭圆 Size axes = Size(img.rows/5,img.cols*2/5); for(int angle = 0;angle<=135;angle+=45) ellipse(img,center,axes,angle,0,360,Scalar(200,200,20)); imshow("img",img); waitKey(0); destroyAllWindows(); return 0; } 
example1



例子(二)

draw_example_2.cpp
#include <opencv2/opencv.hpp>
#include <vector>

using namespace cv; 
using namespace std; 

void drawResult(Mat &img, vector<Point> rois, vector<String> result) {
     for (int i=0; i<result.size(); ++i) {
         if (result[i] == "") { continue; }
         rectangle(img, rois[i*2], rois[i*2+1], Scalar(255,75,75), 2);
         rectangle(img, Point(rois[i*2].x, rois[i*2].y), Point(rois[i*2].x+100, rois[i*2].y+20), Scalar(255,75,75), -1); 
         putText(img, result[i], Point(rois[i*2].x,rois[i*2].y+15), FONT_HERSHEY_SIMPLEX, 0.6, Scalar(255,255,255), 1);
     }
     imshow("result", img);
     waitKey(0);
     destroyAllWindows();
}

int main() {
     Mat img = imread("Strawberry.jpg"); 
     vector<Point> rois = {Point(350, 200), Point(580, 420), Point(185, 270), Point(345, 365), Point(295, 405), Point(490, 615)}; 
     vector<String> labels = {"Strawberry", "Strawberry", "Strawberry"}; 
     drawResult(img, rois, labels); 
     return 0; 
}
example2



例子(三)

draw_example_3.cpp //绘制直线 #include<opencv2/opencv.hpp> #define w 300 using namespace cv; void DrawLine1(Mat img,Point start,Point end); void DrawLine2(Mat img,Point start,Point end); void DrawLine3(Mat img,Point start,Point end); void FilledCircle( Mat img, Point center ); void Ellipse( Mat img, double angle ); int main() { namedWindow("1",WINDOW_NORMAL); Mat image1=Mat::zeros(w,2*w,CV_8UC3); //北 DrawLine2(image1,Point(33,100),Point(33,200)); DrawLine2(image1,Point(10,133),Point(33,133)); DrawLine2(image1,Point(10,166),Point(33,166)); DrawLine2(image1,Point(66,100),Point(66,200)); DrawLine2(image1,Point(90,120),Point(66,150)); DrawLine2(image1,Point(66,200),Point(90,200)); //京 DrawLine2(image1,Point(150,100),Point(150,108)); DrawLine2(image1,Point(110,115),Point(190,115)); DrawLine2(image1,Point(133,130),Point(166,130)); DrawLine2(image1,Point(133,130),Point(133,150)); DrawLine2(image1,Point(166,130),Point(166,150)); DrawLine2(image1,Point(133,150),Point(166,150)); DrawLine2(image1,Point(150,150),Point(150,200)); DrawLine2(image1,Point(150,200),Point(145,195)); DrawLine2(image1,Point(130,190),Point(110,200)); DrawLine2(image1,Point(170,190),Point(190,200)); //理 DrawLine1(image1,Point(210,110),Point(238,110)); DrawLine1(image1,Point(210,150),Point(238,150)); DrawLine1(image1,Point(210,200),Point(238,200)); DrawLine1(image1,Point(224,110),Point(224,200)); DrawLine1(image1,Point(250,100),Point(290,100)); DrawLine1(image1,Point(250,100),Point(250,150)); DrawLine1(image1,Point(290,100),Point(290,150)); DrawLine1(image1,Point(250,150),Point(290,150)); DrawLine1(image1,Point(270,100),Point(270,200)); DrawLine1(image1,Point(250,125),Point(290,125)); DrawLine1(image1,Point(255,175),Point(285,175)); DrawLine1(image1,Point(245,200),Point(295,200)); //工 DrawLine1(image1,Point(310,105),Point(390,105)); DrawLine1(image1,Point(310,200),Point(390,200)); DrawLine1(image1,Point(350,105),Point(350,200)); //大 DrawLine3(image1,Point(460,100),Point(410,200)); DrawLine3(image1,Point(410,133),Point(490,133)); DrawLine3(image1,Point(438,133),Point(490,200)); //学 DrawLine3(image1,Point(550,95),Point(550,107)); DrawLine3(image1,Point(525,100),Point(530,107)); DrawLine3(image1,Point(575,100),Point(570,107)); DrawLine3(image1,Point(510,112),Point(590,112)); DrawLine3(image1,Point(510,112),Point(510,122)); DrawLine3(image1,Point(590,112),Point(590,122)); DrawLine3(image1,Point(535,120),Point(565,120)); DrawLine3(image1,Point(565,120),Point(550,150)); DrawLine3(image1,Point(550,150),Point(550,200)); DrawLine3(image1,Point(550,200),Point(540,190)); DrawLine3(image1,Point(510,150),Point(590,150)); //实心圆 FilledCircle(image1,Point(50,50)); //椭圆 Ellipse(image1,0); Ellipse(image1,90); Ellipse(image1,45); Ellipse(image1,135); imshow("1",image1); waitKey(0); destroyAllWindows(); return 0; } void DrawLine1(Mat img,Point start,Point end) { int thickness = 3; int lineType = 8; line(img, start, end, Scalar(30,150,30), thickness, lineType); } void DrawLine2(Mat img,Point start,Point end) { int thickness = 3; int lineType = 8; line(img, start, end, Scalar(100,200,255), thickness, lineType); } void DrawLine3(Mat img,Point start,Point end) { int thickness = 3; int lineType = 8; line(img, start, end, Scalar(50,25,255), thickness, lineType); } void FilledCircle( Mat img, Point center ) { int thickness = -1; int lineType = 8; circle(img, center, w/40.0, Scalar(0,0,255), thickness, lineType); } void Ellipse( Mat img, double angle ) { int thickness = 1.5; int lineType = 8; ellipse(img, Point(50,50), Size(20,40), angle, 0, 360, Scalar(200, 200, 20), thickness, lineType); } 
example3