图像处理笔记（7）---- OpenCV 绘制无填充矩形

#绘制未填充的矩形
import numpy as np
import cv2 as cv
drawing = False #如果按下鼠标，则为真
mode = True #如果为真，绘制矩形。按m键可以切换到曲线
ix,iy = -1,-1
#鼠标回调函数
def draw_circle(event, x, y, flags, param):
    global ix,iy,drawing,mode
    if event == cv.EVENT_LBUTTONDOWN:
        drawing = True
        ix,iy = x,y
    # elif event == cv.EVENT_MOUSEMOVE:
    #     if drawing == True:
    #         if mode == True:
    #             pass
    #         else:
    #              cv.circle(img,(x.y),5,(0,0,255),1)
    elif event == cv.EVENT_LBUTTONUP:
        drawing = False
        if mode == True:
            cv.rectangle(img, (ix,iy),(x,y),(0,255,0),1)
        else:
            cv.circle(img,(x,y),abs(x-ix),(0,0,255),1)
        
#创建一个黑色的图像，一个窗口，并绑定到窗口的功能
img = np.zeros((512,512,3), np.uint8)
cv.namedWindow('image')
cv.setMouseCallback('image', draw_circle)
while(1):
    cv.imshow('image', img)
    if cv.waitKey(20) & 0xFF == 27:
        break
    elif cv.waitKey(20) & 0xFF == ord('m'):
        mode = not mode
        
cv.destroyAllWindows()

import numpy as np
import cv2 as cv
drawing = False #如果按下鼠标，则为真
mode = True #如果为真，绘制矩形。按m键可以切换到曲线
ix,iy = -1,-1
#鼠标回调函数
def draw_circle(event, x, y, flags, param):
    global ix,iy,drawing,mode
    if event == cv.EVENT_LBUTTONDOWN:
        drawing = True
        ix,iy = x,y
    elif event == cv.EVENT_MOUSEMOVE:
        if drawing == True:
            if mode == True:
                cv.rectangle(img, (ix,iy),(x,y),(0,255,0),-1)
            else:
                cv.circle(img,(x.y),5,(0,0,255),-1)
    elif event == cv.EVENT_LBUTTONUP:
        drawing = False
        if mode == True:
            cv.rectangle(img, (ix,iy),(x,y),(0,255,0),1)
        else:
            cv.circle(img,(x,y),5,(0,0,255),-1)
        
#创建一个黑色的图像，一个窗口，并绑定到窗口的功能
img = np.zeros((512,512,3), np.uint8)
cv.namedWindow('image')
cv.setMouseCallback('image', draw_circle)
while(1):
    cv.imshow('image', img)
    if cv.waitKey(20) & 0xFF == 27:
        break
cv.destroyAllWindows()