如何用OpenCV绘制圆角矩形(带圆角的矩形)?
问题描述:
如何在OpenCV中绘制一个带圆角的矩形?我知道函数ellipse()和line()可以简单地放在一起来绘制它。我只是想知道是否有人以前做过,并且已经把它放在了正确的功能中,以便我可以使用它?理想情况下,角半径需要在参数中进行校准。如何用OpenCV绘制圆角矩形(带圆角的矩形)?
我搜索了很多,但似乎没有人有过这个问题。如果没有人有这样的功能,我可能会在几天后在这里发布我自己的解决方案。
答
我意识到,这是我想的容易得多。这是我的功能。我希望这对某人有帮助。
/**
* Draws a rectangle with rounded corners, the parameters are the same as in the OpenCV function @see rectangle();
* @param cornerRadius A positive int value defining the radius of the round corners.
* @author K
*/
void rounded_rectangle(Mat& src, Point topLeft, Point bottomRight, const Scalar lineColor, const int thickness, const int lineType , const int cornerRadius)
{
/* corners:
* p1 - p2
* | |
* p4 - p3
*/
Point p1 = topLeft;
Point p2 = Point (bottomRight.x, topLeft.y);
Point p3 = bottomRight;
Point p4 = Point (topLeft.x, bottomRight.y);
// draw straight lines
line(src, Point (p1.x+cornerRadius,p1.y), Point (p2.x-cornerRadius,p2.y), lineColor, thickness, lineType);
line(src, Point (p2.x,p2.y+cornerRadius), Point (p3.x,p3.y-cornerRadius), lineColor, thickness, lineType);
line(src, Point (p4.x+cornerRadius,p4.y), Point (p3.x-cornerRadius,p3.y), lineColor, thickness, lineType);
line(src, Point (p1.x,p1.y+cornerRadius), Point (p4.x,p4.y-cornerRadius), lineColor, thickness, lineType);
// draw arcs
ellipse(src, p1+Point(cornerRadius, cornerRadius), Size(cornerRadius, cornerRadius), 180.0, 0, 90, lineColor, thickness, lineType);
ellipse(src, p2+Point(-cornerRadius, cornerRadius), Size(cornerRadius, cornerRadius), 270.0, 0, 90, lineColor, thickness, lineType);
ellipse(src, p3+Point(-cornerRadius, -cornerRadius), Size(cornerRadius, cornerRadius), 0.0, 0, 90, lineColor, thickness, lineType);
ellipse(src, p4+Point(cornerRadius, -cornerRadius), Size(cornerRadius, cornerRadius), 90.0, 0, 90, lineColor, thickness, lineType);
}
答
这里是一个Python实现(万一有人一直在寻找一个):它绘制一个圆角(随机半径和线厚度的改变---如果你想)边界周围的图像:
def addRoundedRectangleBorder(img):
height, width, channels = img.shape
border_radius = int(width * random.randint(1, 10)/100.0)
line_thickness = int(max(width, height) * random.randint(1, 3)/100.0)
edge_shift = int(line_thickness/2.0)
red = random.randint(230,255)
green = random.randint(230,255)
blue = random.randint(230,255)
color = (blue, green, red)
#draw lines
#top
cv2.line(img, (border_radius, edge_shift),
(width - border_radius, edge_shift), (blue, green, red), line_thickness)
#bottom
cv2.line(img, (border_radius, height-line_thickness),
(width - border_radius, height-line_thickness), (blue, green, red), line_thickness)
#left
cv2.line(img, (edge_shift, border_radius),
(edge_shift, height - border_radius), (blue, green, red), line_thickness)
#right
cv2.line(img, (width - line_thickness, border_radius),
(width - line_thickness, height - border_radius), (blue, green, red), line_thickness)
#corners
cv2.ellipse(img, (border_radius+ edge_shift, border_radius+edge_shift),
(border_radius, border_radius), 180, 0, 90, color, line_thickness)
cv2.ellipse(img, (width-(border_radius+line_thickness), border_radius),
(border_radius, border_radius), 270, 0, 90, color, line_thickness)
cv2.ellipse(img, (width-(border_radius+line_thickness), height-(border_radius + line_thickness)),
(border_radius, border_radius), 10, 0, 90, color, line_thickness)
cv2.ellipse(img, (border_radius+edge_shift, height-(border_radius + line_thickness)),
(border_radius, border_radius), 90, 0, 90, color, line_thickness)
return img