OpenCv將圓圈轉換爲多邊形

Question

我想知道在OpenCv中是否有方法將給定半徑的circle轉換爲polygon（例如五邊形或六邊形或類似的東西）？

圈是很容易的：

cv::circle(myMat, center_point, radius, colour, 2, 16); 

，面也十分方便，：

cv::polylines(myMat, points, isClosed, colour, 2, 16); 

我的做法是這樣的：

int length = 150; 
Point center_point(500, 500); 

Point P1; 
P1.x = (int)round(center_point.x + length * cos(0 * CV_PI/180.0)); 
P1.y = (int)round(center_point.y + length * sin(0 * CV_PI/180.0)); 

Point P2; 
P2.x = (int)round(center_point.x + length * cos(45 * CV_PI/180.0)); 
P2.y = (int)round(center_point.y + length * sin(45 * CV_PI/180.0)); 

Point P3; 
P3.x = (int)round(center_point.x + length * cos(90 * CV_PI/180.0)); 
P3.y = (int)round(center_point.y + length * sin(90 * CV_PI/180.0)); 

Point P4; 
P4.x = (int)round(center_point.x + length * cos(135 * CV_PI/180.0)); 
P4.y = (int)round(center_point.y + length * sin(135 * CV_PI/180.0)); 

Point P5; 
P5.x = (int)round(center_point.x + length * cos(180 * CV_PI/180.0)); 
P5.y = (int)round(center_point.y + length * sin(180 * CV_PI/180.0)); 

Point P6; 
P6.x = (int)round(center_point.x + length * cos(225 * CV_PI/180.0)); 
P6.y = (int)round(center_point.y + length * sin(225 * CV_PI/180.0)); 

Point P7; 
P7.x = (int)round(center_point.x + length * cos(270 * CV_PI/180.0)); 
P7.y = (int)round(center_point.y + length * sin(270 * CV_PI/180.0)); 

Point P8; 
P8.x = (int)round(center_point.x + length * cos(315 * CV_PI/180.0)); 
P8.y = (int)round(center_point.y + length * sin(315 * CV_PI/180.0)); 

cv::polylines(myMat, {P1,P2,P3,P4,P5,P6,P7,P8}, isClosed, colour, 2, 16); 

這是工作，但我想知道是否有更聰明的方法來做到這一點？

Answer 1

當然，更聰明的方式確實存在 - 使用數組和循環。

for(i=0;i<N;i++) { 
    P[i].x = (int)round(center_point.x + length * cos(i * 2 * CV_PI/N)); 
    P[i].y = (int)round(center_point.y + length * sin(i * 2 * CV_PI/N)); 
}