PyQt5中按钮连接有什么问题? [英] What is the problem with buttons connection in PyQt5?

问题描述

我的问题是我无法连接两个按钮之间的实现.在我按下灰度"按钮并获得灰度图像后，我按下Canny"按钮但用户界面突然关闭.我不知道我的代码有什么问题.

I have the problem that I cannot connect the implementation between two buttons. After I pressed the "Grayscale" button and got the grayscale image, I pressed the "Canny" button but the user interface suddenly closed. I don't know what's wrong in my code.

def getImage(self):
    global fname
    fname = QFileDialog.getOpenFileName(self, 'Open file', 
       'C:\\Users\binil-ping\Desktop\CODE',"Image Files (*.jpg *.gif *.bmp *.png)")
    pixmap = QPixmap(fname[0])
    self.label.setPixmap(QPixmap(pixmap))
    self.resize(pixmap.width(), pixmap.height())

def Grayscale(self):
    global edges
    edges = cv2.imread(fname[0], 0)
    edges = cv2.GaussianBlur(edges, (5, 5), 0)
    height, width = edges.shape[:2]
    ret,edges = cv2.threshold(edges,150,255,cv2.THRESH_BINARY)
    kernel = np.ones((5,5),np.uint8)
    edges = cv2.morphologyEx(edges, cv2.MORPH_OPEN, kernel)
    edges = cv2.morphologyEx(edges, cv2.MORPH_OPEN, kernel)

    edges = QImage(edges, width, height, QImage.Format_Grayscale8)
    pixmap = QPixmap.fromImage(edges)
    self.label.setPixmap(pixmap)
    self.resize(pixmap.width(), pixmap.height())

def Canny(self):
    edges2 = cv2.imread(edges[0],-1)
    edges2 = cv2.Canny(edges2,180,200)

    edges2 = QImage(edges2, width, height, QImage.Format_Grayscale8)
    pixmap = QPixmap.fromImage(edges2)
    self.label.setPixmap(pixmap)
    self.resize(pixmap.width(), pixmap.height())

推荐答案

您的代码存在很多问题(包括您没有提供 最小的、可重现的示例)，其中一些解释了崩溃或可能导致另一个崩溃(我用 [*] 标记了它们):

There are a lot of problems with your code (including the fact that you didn't provide a minimal, reproducible example), some of them explaining the crash or possibly leading to another one (I've marked them with [*]):

• 正如已经指出的那样，尽可能避免使用全局变量(几乎总是这样)，而是使用类属性；
• 你不断地覆盖这些全局变量，使调试变得非常混乱；实际上，您将 edges 用于 numpy 数组 和 QImage;
• [*] 您正在尝试 cv2.imread(edges[0],-1)，但不仅 imread 需要一个字符串，而且由于上一点，在那个point edges 甚至是一个 QImage;
• [*] 一些变量没有在函数范围内声明(Canny 函数中的宽度/高度)；
• 你真的应该避免对函数和变量使用大写的名字，因为它们通常只用于类名和内置常量；
• 在转换回 QImage 时存在一些问题，我想这是由于您对数组应用的各种转换(其中一些似乎也是不必要的)对 Format_Grayscale8 格式不太友好，也许您应该更好地调查一下；

• as already pointed out, avoid using globals whenever possible (which is almost always), use class attributes instead;
• you are continuously overwriting those globals, making everything very confusing also for debugging; in fact you're using edges for both a numpy array and a QImage;
• [*] you are trying to cv2.imread(edges[0],-1), but not only imread expects a string, but, as a result of the previous point, at that point edges is even a QImage;
• [*] some variables are not declared in the scope of the function (width/height in the Canny function);
• you should really avoid using capitalized names for functions and variables, as they are usually only for class names and builtin constants;
• there are some issues in the conversion back to QImage, I suppose that's due to the various transformations you're applying to to the array (some of them also seem unnecessary) that are not very friendly with the Format_Grayscale8 format, perhaps you should better investigate about that;

这是对您的代码的可能改进.我正在添加小部件创建部分，因为它在原始示例中缺失.

Here's a possible improvement over your code. I'm adding the widget creation parts, as it was missing in the original example.

class ShowImage(QWidget):
    def __init__(self):
        QWidget.__init__(self)
        layout = QVBoxLayout(self)
        self.label = QLabel()
        layout.addWidget(self.label)

        self.getImageBtn = QPushButton()
        layout.addWidget(self.getImageBtn)
        self.getImageBtn.clicked.connect(self.getImage)

        self.grayBtn = QPushButton('gray')
        layout.addWidget(self.grayBtn)
        self.grayBtn.clicked.connect(self.grayScale)

        self.cannyBtn = QPushButton('canny')
        layout.addWidget(self.cannyBtn)
        self.cannyBtn.clicked.connect(self.canny)

        self.fileName = None
        self.edges = None

    def getImage(self):
        fname = QFileDialog.getOpenFileName(self, 'Open file', 
           'C:\\Users\binil-ping\Desktop\CODE',"Image Files (*.jpg *.gif *.bmp *.png)")
        if fname[0]:
            self.fileName = fname[0]
            pixmap = QPixmap(self.fileName)
            self.label.setPixmap(pixmap)

    def grayScale(self):
        if not self.fileName:
            return
        edges = cv2.imread(self.fileName, 0)
        edges = cv2.GaussianBlur(edges, (5, 5), 0)
        ret,edges = cv2.threshold(edges, 150, 255, cv2.THRESH_BINARY)
        kernel = np.ones((5, 5), np.uint8)
        edges = cv2.morphologyEx(edges, cv2.MORPH_OPEN, kernel)
        edges = cv2.morphologyEx(edges, cv2.MORPH_OPEN, kernel)

        self.edges = edges
        height, width = edges.shape[:2]
        image = QImage(edges, width, height, QImage.Format_Grayscale8)
        pixmap = QPixmap.fromImage(image)
        self.label.setPixmap(pixmap)

    def canny(self):
        if self.edges is None:
            return
        edges2 = cv2.Canny(self.edges, 180, 200)
        height, width = edges2.shape[:2]

        edges2 = QImage(edges2, width, height, QImage.Format_Grayscale8)
        pixmap = QPixmap.fromImage(edges2)
        self.label.setPixmap(pixmap)

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