setMouseCallback onmouse 未定义答案

【问题标题】：setMouseCallback onmouse is not definedsetMouseCallback onmouse 未定义
【发布时间】：2020-06-16 02:26:55
【问题描述】：

def __init__(self):
    super(FindWindow, self).__init__()
    uic.loadUi('D:/Python/Projects/Sensor/roi.ui', self)
    self.init_ui()

def init_ui(self):
    self.pushButton_roi.clicked.connect(self.open_picture)

def onMouse(event, x, y, flags, param):
    global drawing, ix, iy
    if event == cv2.EVENT_LBUTTONDOWN:
        drawing = True
        ix, iy = x, y

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

    elif event == cv2.EVENT_LBUTTONUP:
        drawing = False
        cv2.rectangle(param, (ix, iy), (x, y), (0, 0, 0), -1)

def open_picture(self, what):
    img = cv2.imread(file_directory)
    temp = what
    print(temp)
    cv2.namedWindow('paint')
    cv2.setMouseCallback('paint', onMouse, param=img)

    while True:
        cv2.imshow('paint', img)
        k = cv2.waitKey(1) & 0xFF

        if k == 27:
            break

我正在尝试在 pyqt 上使用鼠标回调函数来设置图片的 ROI。我查看了鼠标回调函数的示例代码，示例代码没有问题。然后，我如上图用pyqt实现了它，现在它给了我如下错误。

Traceback (most recent call last):
  File "D:/Python/Projects/Sensor/one_detect_main.py", line 49, in open_picture
    cv2.setMouseCallback('paint', onMouse, param=img)
NameError: name 'onMouse' is not defined

我不知道示例代码和我的代码有什么区别。下面是示例代码：

import numpy as np
import cv2
from random import shuffle
import math

mode, drawing = True, False
ix, iy = -1, -1
B = [i for i in range(256)]
G = [i for i in range(256)]
R = [i for i in range(256)]


def onMouse(event, x, y, flags, param):
    global ix, iy, drawing, mode, B, G, R

    if event == cv2.EVENT_LBUTTONDOWN:
        drawing = True
        ix, iy = x, y
        shuffle(B), shuffle(G), shuffle(R)

    elif event == cv2.EVENT_MOUSEMOVE:
        if drawing:
            if mode:
                cv2.rectangle(param, (ix, iy), (x, y), (B[0], G[0], R[0]), -1)
            else:
                r = (ix-x) ** 2 + (iy-y)**2
                r = int(math.sqrt(r))
                cv2.circle(param, (ix, iy), r, (B[0], G[0], R[0]), -1)

    elif event == cv2.EVENT_LBUTTONUP:
        drawing = False
        if mode:
            cv2.rectangle(param, (ix, iy), (x, y), (B[0], G[0], R[0]), -1)
        else:
            r = (ix-x)**2 + (iy-y)**2
            r = int(math.sqrt(r))
            cv2.circle(param, (ix, iy), r, (B[0], G[0], R[0]), -1)

def mouseBrush():
    global mode

    img = np.zeros((512, 512, 3), np.uint8)
    cv2.namedWindow('paint')
    cv2.setMouseCallback('paint', onMouse, param=img)

    while True:
        cv2.imshow('paint', img)
        k = cv2.waitKey(1) & 0xFF

        if k == 27:
            break
        elif k == ord('m'):
            mode = not mode

    cv2.destroyAllWindows()

mouseBrush()

【问题讨论】：

请提供minimal reproducible example
这个例子对你有用吗？
尽管第一段代码被从上下文中删除（因此不是 minimal reproducible example），事实上有一个__init__ 并且所有其他功能比onMouse 有self 作为第一个参数表明所有这些都是类定义的一部分......这可以解释为什么试图引用onMouse 好像它是独立的是行不通的。
@DanMašek 你是对的。我的问题已通过将 self 添加到 onMouse 来解决。

标签： python opencv pyqt signals

【解决方案1】：

从示例代码中，onMouse 是他们定义的一个函数，它接收一个事件和其他参数。通过使用 mouseCallBack 函数，只要鼠标做某事，onMouse 就会被调用。

def onMouse(event, x, y, flags, param):
 # handle the event here

另外，请注意在 onMouse 内部它们处理不同的事件

if event == cv2.EVENT_LBUTTONDOWN:
 # do something  
elif event == cv2.EVENT_MOUSEMOVE:
 # do something

【讨论】：