Python 缩进错误：waitkey中应有缩进块

这是您当前的代码：

import cv2

import numpy as np

#variables

#True while mouse button down, False while mouse button up

drawing = False

ix,iy = -1

#Function

def draw_rectangle(event,x,y,param,flags):

    global ix,iy,drawing

    if event == cv2.EVENT_LBUTTONDOWN:

        drawing = True

        ix,iy = x,y

    elif event == cv2.EVENT_MOUSEMOVE:

        if drawing == True:

        cv2.rectangle(img,(ix,iy),(x,y),(255,0,0),-1)

    elif event == cv2.EVENT_LBUTTONUP:

        drawing = False

        cv2.rectangle(img,(ix,iy),(x,y),(255,0,0),-1)

#Showing images with opencv

#black

img = np.zeros((612,612,3))

cv2.namedwindow(winname='draw_painting')

cv2.setMouseCallback('draw_painting',draw_rectangle)

while True:


        cv2.imshow('draw_painting',img)

        cv2.waitkey(20) & 0xFF = 27:

            break

    cv2.destryAllWindows()

请注意，在if语句之后，需要缩进代码：

elif event == cv2.EVENT_MOUSEMOVE:
    if drawing == True:
    cv2.rectangle(img,(ix,iy),(x,y),(255,0,0),-1)

其他错误：

---

此外，您似乎希望最终的if语句位于if块内，并记住使用

=

而不是

=

来检查是否相等。

您需要为if语句后的行提供缩进

elif event == cv2.EVENT_MOUSEMOVE:
    if drawing == True:
        cv2.rectangle(img,(ix,iy),(x,y),(255,0,0),-1)

---

tab if语句后的cv2.矩形（img，（ix，iy），（x，y），（255,0,0），-1）。问题是if语句中没有任何内容，因为if结果在同一个缩进行上。您将

if drawing==True:

block留空，这就是它要求在下一行缩进的原因。您非常聪明，并且您的解释可以到达想要缩进的人

elif event == cv2.EVENT_MOUSEMOVE:
    if drawing == True:
        cv2.rectangle(img,(ix,iy),(x,y),(255,0,0),-1)

if drawing == True:

    cv2.rectangle(img,(ix,iy),(x,y),(255,0,0),-1)