如何在 OpenCV 中绘制圆角矩形？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它并将其放入适当的功能中以便我可以使用它？理想情况下，拐角半径是在参数中进行校准的。
我为此搜索了很多，但似乎以前没有人遇到过这个问题。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。
问问题
15236 次
3 回答
14
我意识到，这比我想象的要容易得多。这是我的功能。我希望它对某人有帮助。
/**
* 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 );
}
于 2013-09-24T07:25:34.767 回答
6
这是具有填充/未填充功能的 python 版本，corner_radius 根据图像的高度自动计算。
import cv2
import numpy as np
def rounded_rectangle(src, top_left, bottom_right, radius=1, color=255, thickness=1, line_type=cv2.LINE_AA):
# corners:
# p1 - p2
# | |
# p4 - p3
p1 = top_left
p2 = (bottom_right[1], top_left[1])
p3 = (bottom_right[1], bottom_right[0])
p4 = (top_left[0], bottom_right[0])
height = abs(bottom_right[0] - top_left[1])
if radius > 1:
radius = 1
corner_radius = int(radius * (height/2))
if thickness < 0:
#big rect
top_left_main_rect = (int(p1[0] + corner_radius), int(p1[1]))
bottom_right_main_rect = (int(p3[0] - corner_radius), int(p3[1]))
top_left_rect_left = (p1[0], p1[1] + corner_radius)
bottom_right_rect_left = (p4[0] + corner_radius, p4[1] - corner_radius)
top_left_rect_right = (p2[0] - corner_radius, p2[1] + corner_radius)
bottom_right_rect_right = (p3[0], p3[1] - corner_radius)
all_rects = [
[top_left_main_rect, bottom_right_main_rect],
[top_left_rect_left, bottom_right_rect_left],
[top_left_rect_right, bottom_right_rect_right]]
[cv2.rectangle(src, rect[0], rect[1], color, thickness) for rect in all_rects]
# draw straight lines
cv2.line(src, (p1[0] + corner_radius, p1[1]), (p2[0] - corner_radius, p2[1]), color, abs(thickness), line_type)
cv2.line(src, (p2[0], p2[1] + corner_radius), (p3[0], p3[1] - corner_radius), color, abs(thickness), line_type)
cv2.line(src, (p3[0] - corner_radius, p4[1]), (p4[0] + corner_radius, p3[1]), color, abs(thickness), line_type)
cv2.line(src, (p4[0], p4[1] - corner_radius), (p1[0], p1[1] + corner_radius), color, abs(thickness), line_type)
# draw arcs
cv2.ellipse(src, (p1[0] + corner_radius, p1[1] + corner_radius), (corner_radius, corner_radius), 180.0, 0, 90, color ,thickness, line_type)
cv2.ellipse(src, (p2[0] - corner_radius, p2[1] + corner_radius), (corner_radius, corner_radius), 270.0, 0, 90, color , thickness, line_type)
cv2.ellipse(src, (p3[0] - corner_radius, p3[1] - corner_radius), (corner_radius, corner_radius), 0.0, 0, 90, color , thickness, line_type)
cv2.ellipse(src, (p4[0] + corner_radius, p4[1] - corner_radius), (corner_radius, corner_radius), 90.0, 0, 90, color , thickness, line_type)
return src
用法：
top_left = (0, 0)
bottom_right = (500, 800)
color = (255, 255, 255)
image_size = (500, 800, 3)
img = np.zeros(image_size)
img = rounded_rectangle(img, top_left, bottom_right, color=color, radius=0.5, thickness=-1)
cv2.imshow('rounded_rect', img)
cv2.waitKey(0)
于 2020-02-13T14:58:30.043 回答
3
这是一个 Python 实现（以防万一有人在寻找）：它在图像周围绘制一个圆角（随机半径和线粗——如果需要，可以更改）边框：
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
于 2017-04-01T16:37:43.860 回答