Qslider 不会在 PyQt5 中传递参数

Question

slider 值更改时我的功能将无法工作我不知道为什么？这是我第一次使用PyQt5。

from PIL.ImageQt import Image, ImageQt
from PIL import ImageEnhance

from PyQt5.QtWidgets import (QApplication, QDialog, QGridLayout,
                             QLabel, QPushButton, QGroupBox,
                             QSlider, QVBoxLayout, QFileDialog)
from PyQt5.QtCore import Qt
from PyQt5.QtGui import QPixmap, QIcon


class MainWindow(QDialog):
    def __init__(self):
        super(MainWindow,self).__init__()

        self.originalPalette = QApplication.palette()
#        self.setAcceptDrops(True)

        self.createTopGroupBox()
        self.createBottomGroupBox()
#        self.color("blue")

        mainLayout = QGridLayout()
        mainLayout.addWidget(self.topGroupBox, 0, 0)
        mainLayout.addWidget(self.bottomGroupBox, 1, 0)        
        #mainLayout.setRowStretch(1, 1)
        #mainLayout.setRowStretch(2, 1)
        #mainLayout.setColumnStretch(0, 1)
        #mainLayout.setColumnStretch(1, 1)
        self.setLayout(mainLayout)

        self.setWindowTitle("Photo Editor")    
        self.resize(800, 800)

    def createTopGroupBox(self):  

        self.topGroupBox = QGroupBox()
        openImgButton = QPushButton("Open Image")
        openImgButton.clicked.connect(self.getImage)
        self.label = QLabel("Your Photo")

        layout = QVBoxLayout()
        layout.addWidget(openImgButton)
        layout.addWidget(self.label)
        layout.addStretch(1)
        self.topGroupBox.setLayout(layout)

    def getImage(self):
        global fname
        fname = QFileDialog.getOpenFileName(self, 'Open file',
               'c:\ ', "Image files (*.jpeg *.jpg *.gif *.bmp *.png))")
        imagePath = fname[0]
        #pixmap = QPixmap(imagePath)
        self.image = Image.open(imagePath)
        self.qimage = ImageQt(self.image)
        self.label.setPixmap(QPixmap.fromImage(self.qimage))
        self.resize(self.qimage.width(), self.qimage.height())

    def createBottomGroupBox(self):

        self.bottomGroupBox = QGroupBox()

        self.sliderBrightness = QSlider(Qt.Horizontal, self)
        brightnessLabel = QLabel("Brightness:")
        brightnessLabel.setBuddy(self.sliderBrightness)
        self.sliderBrightness.setTickPosition(QSlider.TicksBelow)
        self.sliderBrightness.setTickInterval(1)
        self.sliderBrightness.setValue(100)
        self.sliderBrightness.setMinimum(0)
        self.sliderBrightness.setMaximum(200)
        self.brightnessValueLabel = QLabel("1")

        self.sliderContrast = QSlider(Qt.Horizontal, self)
        contrastLabel = QLabel("Contrast:")
        contrastLabel.setBuddy(contrastLabel)
        self.sliderContrast.setValue(1)
        self.sliderContrast.setMinimum(0)
        self.sliderContrast.setMaximum(2)
        self.contrastValueLabel = QLabel("1")

        sliderSharpness = QSlider(Qt.Horizontal, self)
        sharpnessLabel = QLabel("Sharpness:")
        sharpnessLabel.setBuddy(sharpnessLabel)
        sliderSharpness.setValue(1)
        sliderSharpness.setMinimum(0)
        sliderSharpness.setMaximum(2)
        self.sharpnessValueLabel = QLabel("1")

        savePushButton = QPushButton("Save")
        savePushButton.clicked.connect(self.saveImage("image.png", "PNG"))

        self.sliderBrightness.valueChanged.connect(self.valueChangeBrightness)
        self.sliderContrast.valueChanged.connect(self.valueChangeContrast)
        sliderSharpness.valueChanged.connect(self.valueChangeSharpness)

        layout = QVBoxLayout()
        layout.addWidget(brightnessLabel)
        layout.addWidget(self.sliderBrightness, 0)
        layout.addWidget(self.brightnessValueLabel)
        layout.addWidget(contrastLabel)
        layout.addWidget(self.sliderContrast, 1)
        layout.addWidget(sharpnessLabel)
        layout.addWidget(sliderSharpness, 2)
        layout.addWidget(savePushButton, 3)
        self.bottomGroupBox.setLayout(layout)

    def saveImage(self, fileName, fileFormat):
        self.editImage.save(fileName, fileFormat)            

    def valueChangeBrightness(self, sliderValue):

        factor = float(sliderValue)/100
        enhancer_object = ImageEnhance.Brightness(self.image)
        self.editImage = enhancer_object.enhance(factor)
        self.brightnessValueLabel.setText(str(self.sliderBrightness.value()))       

    def valueChangeContrast(self, factor):

        enhancer_object = ImageEnhance.Contrast(self.image)
        enhancer_object.enhance(factor)

    def valueChangeSharpness(self, factor):

        enhancer_object = ImageEnhance.Sharpness(self.image)
        enhancer_object.enhance(factor)


if __name__ == '__main__':

    import sys

    app = QApplication(sys.argv)
    window = MainWindow()
    window.show()
    sys.exit(app.exec_())

Answer 1

OP 代码中的主要问题是它没有更新显示的图像。例如，如果查看文档，则可以理解为，增强方法返回修改后的图像，但既不保存也不显示。

另一方面，更改的应用必须是级联的（一个接一个）。

还有诸如未验证文件名是否为空字符串等错误，此外单击信号连接到关闭，而不是评估函数返回。

综合以上，解决办法是：

from PIL.ImageQt import Image, ImageQt
from PIL import ImageEnhance

from PyQt5.QtCore import Qt
from PyQt5.QtGui import QPixmap
from PyQt5.QtWidgets import (
    QApplication,
    QDialog,
    QGridLayout,
    QLabel,
    QPushButton,
    QGroupBox,
    QSlider,
    QVBoxLayout,
    QFileDialog,
)


class MainWindow(QDialog):
    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)
        self.createTopGroupBox()
        self.createBottomGroupBox()
        mainLayout = QGridLayout(self)
        mainLayout.addWidget(self.topGroupBox, 0, 0)
        mainLayout.addWidget(self.bottomGroupBox, 1, 0)

        self.setWindowTitle("Photo Editor")
        self.resize(800, 800)

        self.input_image = None
        self.output_image = None

    def createTopGroupBox(self):
        self.topGroupBox = QGroupBox()
        openImgButton = QPushButton("Open Image")
        openImgButton.clicked.connect(self.getImage)
        self.label = QLabel("Your Photo")

        layout = QVBoxLayout()
        layout.addWidget(openImgButton)
        layout.addWidget(self.label)
        layout.addStretch(1)
        self.topGroupBox.setLayout(layout)

    def getImage(self):
        fname, _ = QFileDialog.getOpenFileName(
            self, "Open file", "", "Image files (*.jpeg *.jpg *.gif *.bmp *.png)"
        )
        if fname:
            self.input_image = Image.open(fname)
            self.show_image(self.input_image)

    def show_image(self, image):
        qimage = ImageQt(image)
        self.label.setPixmap(QPixmap.fromImage(qimage))

    def createBottomGroupBox(self):
        self.bottomGroupBox = QGroupBox()
        self.sliderBrightness = QSlider(
            Qt.Horizontal,
            tickPosition=QSlider.TicksBelow,
            tickInterval=1,
            value=100,
            minimum=0,
            maximum=200,
        )
        brightnessLabel = QLabel("Brightness:")
        brightnessLabel.setBuddy(self.sliderBrightness)

        self.brightnessValueLabel = QLabel()
        self.brightnessValueLabel.setNum(self.sliderBrightness.value())

        self.sliderContrast = QSlider(Qt.Horizontal, value=1, minimum=0, maximum=2)
        contrastLabel = QLabel("Contrast:")
        contrastLabel.setBuddy(self.sliderContrast)
        self.contrastValueLabel = QLabel()
        self.contrastValueLabel.setNum(self.sliderContrast.value())

        self.sliderSharpness = QSlider(Qt.Horizontal, value=1, minimum=0, maximum=2)
        sharpnessLabel = QLabel("Sharpness:")
        sharpnessLabel.setBuddy(self.sliderSharpness)
        self.sharpnessValueLabel = QLabel()
        self.sharpnessValueLabel.setNum(self.sliderSharpness.value())

        savePushButton = QPushButton("Save")
        savePushButton.clicked.connect(lambda: self.saveImage("image.png", "PNG"))

        self.sliderBrightness.valueChanged.connect(self.update_image)
        self.sliderContrast.valueChanged.connect(self.update_image)
        self.sliderSharpness.valueChanged.connect(self.update_image)

        layout = QVBoxLayout()
        layout.addWidget(brightnessLabel)
        layout.addWidget(self.sliderBrightness)
        layout.addWidget(self.brightnessValueLabel)

        layout.addWidget(contrastLabel)
        layout.addWidget(self.sliderContrast)
        layout.addWidget(self.contrastValueLabel)

        layout.addWidget(sharpnessLabel)
        layout.addWidget(self.sliderSharpness)
        layout.addWidget(self.sharpnessValueLabel)

        layout.addWidget(savePushButton)
        self.bottomGroupBox.setLayout(layout)

    def saveImage(self, fileName, fileFormat):
        if self.output_image is not None:
            self.output_image.save(fileName, fileFormat)

    def update_image(self):
        if self.input_image is not None:
            factor_brightness = self.sliderBrightness.value() / 100.0
            factor_contrast = self.sliderContrast.value()
            factor_sharpness = self.sliderSharpness.value()

            enhancer_object = ImageEnhance.Brightness(self.input_image)
            image = enhancer_object.enhance(factor_brightness)
            enhancer_object = ImageEnhance.Contrast(image)
            image = enhancer_object.enhance(factor_contrast)
            enhancer_object = ImageEnhance.Sharpness(image)
            self.output_image = enhancer_object.enhance(factor_sharpness)
            self.show_image(self.output_image)


if __name__ == "__main__":

    import sys

    app = QApplication(sys.argv)
    window = MainWindow()
    window.show()
    sys.exit(app.exec_())