如何在python中从pyqt4升级到pyqt5

将PyQt4代码转换为PyQt5并非易事：

• PyQt4和PyQt5分别是Qt4和Qt5的包装，因此两者都受该过渡的变化的影响，而过渡之一是Qt4的QtGui子模块被划分为Qt5的QtGui和QtWidgets子模块。
• 不推荐使用某些类和方法，因此必须找到等效项（如果存在）。

在这两种情况都发生的情况下，第一种情况的解决方案很简单：您必须查看Qt文档并检查它属于哪个子模块，例如QToolTip，在顶部有一个表：

并且部分QT += widgets表明它属于QtWidgets子模块。

但是第二种情况有些复杂，因为它涉及寻找可能在同一类中或可能不在同一类中的等效项，在这种情况下，QPixmap.grabWindow()它是通过不赞成使用的方法发生的（请参阅此处以获取更多信息）。搜索后，您可以将代码替换为QApplication.primaryScreen().grabWindow(0)。

考虑到以上所有内容，翻译为：

import sys
from PyQt5.QtCore import QRectF, Qt
from PyQt5.QtGui import QColor, QFont, QPainter, QPixmap, QTextOption, QScreen
from PyQt5.QtWidgets import QApplication, QToolTip, QWidget


class AreaSelector(QWidget):
    def __init__(self, parent=None):

        QWidget.__init__(self, None, Qt.FramelessWindowHint)
        self.setAttribute(Qt.WA_TranslucentBackground)
        self.setAttribute(Qt.WA_DeleteOnClose)
        self.setWindowState(Qt.WindowFullScreen)
        self.setAutoFillBackground(False)

        self.parent = parent
        self.start_x = 0
        self.start_y = 0
        self.end_x = 0
        self.end_y = 0
        self.current_x = 0
        self.current_y = 0

    def showEvent(self, event):
        self.bg = QApplication.primaryScreen().grabWindow(0)
        self.screen_geometry = QApplication.primaryScreen().geometry()

    def mousePressEvent(self, event):

        self.start_x = event.globalX()
        self.start_y = event.globalY()

    def mouseReleaseEvent(self, event):

        self.end_x = event.globalX()
        self.end_y = event.globalY()

    def mouseMoveEvent(self, event):

        self.current_x = event.globalX()
        self.current_y = event.globalY()
        self.repaint()

        text = "Start: %sx%s \nEnd: %sx%s" % (
            self.start_x,
            self.start_y,
            self.current_x,
            self.current_y,
        )
        QToolTip.showText(event.pos(), text)

    def keyPressEvent(self, event):
        if event.key() == Qt.Key_Return:
            self._acceptSelection()
        elif event.key() == Qt.Key_Escape:
            self.close()

    def _acceptSelection(self):

        if self.parent is not None:
            self.parent.areaSelectEvent(
                self.start_x, self.start_y, self.end_x, self.end_y
            )
        self.close()

    def paintEvent(self, event):

        painter = QPainter()
        painter.begin(self)

        painter.fillRect(self.screen_geometry, QColor(10, 10, 10, 125))

        self._paint_selection(painter)
        self._paint_usage_text(painter)
        painter.end()

    def _paint_usage_text(self, painter):

        font = QFont("Helvetica [Cronyx]", 26, QFont.Bold)
        painter.setFont(font)
        painter.setPen(QColor(255, 255, 255, 255))

        screen_width = self.screen_geometry.width()
        text_width = 800
        text_start_x = screen_width / 2 - text_width / 2

        screen_height = self.screen_geometry.height()
        text_height = 200
        text_start_y = screen_height / 2 - text_height / 2

        textoption = QTextOption(Qt.AlignCenter)
        textbox = QRectF(text_start_x, text_start_y, text_width, text_height)
        painter.drawText(
            textbox,
            "Click & Drag to select an area\n" "ENTER to confirm or ESC to cancel",
            textoption,
        )
        painter.drawRoundedRect(textbox, 20, 20)

    def _paint_selection(self, painter):
        """Draws the current user selection"""
        rectangle = QRectF()

        if self.start_x > self.current_x:
            rectangle.setLeft(self.current_x)
            rectangle.setRight(self.start_x)

        else:
            rectangle.setLeft(self.start_x)
            rectangle.setRight(self.current_x)

        if self.start_y > self.current_y:
            rectangle.setTop(self.current_y)
            rectangle.setBottom(self.start_y)

        else:
            rectangle.setTop(self.start_y)
            rectangle.setBottom(self.current_y)

        painter.drawPixmap(rectangle, self.bg, rectangle)
        painter.drawRect(rectangle)


if __name__ == "__main__":
    app = QApplication(sys.argv)
    main = AreaSelector()
    main.show()
    sys.exit(app.exec_())