图片格式转换为jpg

#!/usr/bin/python3
# -*- coding: utf-8 -*-

from PyQt5 import QtWidgets, QtCore, QtGui

from PyQt5.QtWidgets import (QApplication, QWidget, QPushButton, QTextEdit,
                             QHBoxLayout, QLineEdit, QGroupBox, QFormLayout,
                             QSlider, QLabel, QFileDialog, QMessageBox)
from PyQt5.QtCore import Qt
from PIL import Image
import os
import sys


class image2jpgWindow(QWidget):

    def __init__(self):
        super().__init__()

        self.initUI()

    def initUI(self):
        self.setWindowTitle('image2jpg')
        self.resize(600, 150)

        srcFoldChooser = QHBoxLayout()
        self.srcFoldName = QLineEdit()
        self.srcFoldName.setFocusPolicy(Qt.NoFocus)
        self.srcFoldBtn = QPushButton('打开')
        self.srcFoldBtn.clicked.connect(self.chooseSrcFolder)
        srcFoldChooser.addWidget(self.srcFoldName)
        srcFoldChooser.addWidget(self.srcFoldBtn)

        desFoldChooser = QHBoxLayout()
        self.desFoldName = QLineEdit()
        self.desFoldName.setFocusPolicy(Qt.NoFocus)
        self.desFoldBtn = QPushButton('另存为')
        self.desFoldBtn.clicked.connect(self.chooseDesFolder)
        desFoldChooser.addWidget(self.desFoldName)
        desFoldChooser.addWidget(self.desFoldBtn)

        confirmBox = QHBoxLayout()
        self.qualitySlider = QSlider(Qt.Horizontal)
        self.qualitySlider.setMaximum(100)
        self.qualitySlider.setMinimum(20)
        self.qualitySlider.setSingleStep(10)
        # self.qualitySlider.setTickPosition(QSlider.TicksBelow)
        self.qualitySlider.setTickInterval(10)
        self.qualitySlider.setValue(100)
        self.qualitySlider.valueChanged.connect(self.valChange)
        self.qualityLabel1 = QLabel('图片质量:')
        self.qualityLabel2 = QLabel('100')
        self.qualityLabel3 = QLabel('%')
        self.confirmBtn = QPushButton('开始转换')
        self.confirmBtn.clicked.connect(self.startExchange)
        confirmBox.addWidget(self.qualityLabel1)
        confirmBox.addWidget(self.qualitySlider)
        confirmBox.addWidget(self.qualityLabel2)
        confirmBox.addWidget(self.qualityLabel3)
        confirmBox.addWidget(self.confirmBtn)

        srcFoldGroup = QGroupBox('')
        srcFoldGroup.setLayout(srcFoldChooser)
        desFoldGroup = QGroupBox('')
        desFoldGroup.setLayout(desFoldChooser)
        confirmGroup = QGroupBox('')
        confirmGroup.setLayout(confirmBox)
        layout = QFormLayout()
        layout.addWidget(srcFoldGroup)
        layout.addWidget(desFoldGroup)
        layout.addWidget(confirmGroup)
        self.setLayout(layout)
        # btn = QPushButton('Hello')
        # btn = QPushButton('Hello', self)
        # textEdit = QTextEdit(self)
        self.show()

    def valChange(self):
        self.qualityLabel2.setNum(self.qualitySlider.value())

    def chooseSrcFolder(self):
        # 选择要转换图片的文件夹
        srcDirectoy = QFileDialog.getExistingDirectory(self, '打开要转换图片的文件夹', "./")
        # srcDirectoy = srcDirectoy.replace('/', '\\')
        self.srcFoldName.setText(srcDirectoy)

    def chooseDesFolder(self):
        # 选择目标文件夹
        desDirectoy = QFileDialog.getExistingDirectory(self, '打开目标文件夹', "./")
        # desDirectoy = desDirectoy.replace('/', '\\')
        self.desFoldName.setText(desDirectoy)

    def startExchange(self):
        if self.srcFoldName.text() == "":
            QMessageBox.critical(self, 'image2jpg', '源文件夹为空！', QMessageBox.Yes, QMessageBox.Yes)
            return
        if not os.path.exists(self.srcFoldName.text()):
            QMessageBox.critical(self, 'image2jpg', '源文件夹不存在或路径非法！', QMessageBox.Yes, QMessageBox.Yes)
            return
        if self.desFoldName.text() == "":
            QMessageBox.critical(self, 'image2jpg', '目标文件夹为空！', QMessageBox.Yes, QMessageBox.Yes)
            return
        elif not os.path.exists(self.srcFoldName.text()):
            QMessageBox.critical(self, 'image2jpg', '目标文件夹不存在或路径非法！', QMessageBox.Yes, QMessageBox.Yes)
            return

        for file in os.listdir(self.srcFoldName.text()):
            # src = os.path.join(self.srcFoldName.text(), file)
            src = os.path.join(self.srcFoldName.text(), file)
            print(self.srcFoldName.text())
            print(src)
            try:
                image = Image.open(src)
                dest = self.desFoldName.text() + "/" + os.path.splitext(file)[0] + ".jpg"
                print(dest)
                image.save(dest, quality=self.qualitySlider.value())
                print("image to jpg sucess: " + file)
            except:
                print("image to jpg fail: " + file)
                reply = QMessageBox.question(self, 'image2jpg', '文件' + file + '转换出错，请问继续吗？',
                                             QMessageBox.Yes | QMessageBox.No, QMessageBox.No)
                if reply == QMessageBox.No:
                    print("yes")
                else:
                    return


if __name__ == '__main__':
    app = QApplication(sys.argv)
    mainWindow = image2jpgWindow()
    sys.exit(app.exec_())