Python 屏幕截图程序-透明截图区域

我正在将我成功的截屏程序从Tkinter转换为PYQT5。我的问题是如何创建一个完全透明的剪切区域（一个动态更新的正方形区域会更好）。广场的外部将是半透明的。我在stack overflow和internet上到处都找过，但找不到这样的示例（其他示例不是完全透明的绘图窗口）。我已经附上了我的代码和我正在寻找的图片示例。“SnippingWidget”是执行剪切逻辑的类

---

必须使用

QPainterPath

从窗口中减去所选矩形：

import sys

from PyQt5 import QtCore, QtGui, QtWidgets

from PIL import ImageGrab


class App(QtWidgets.QMainWindow):
    def __init__(self):
        super().__init__()

        self.initUI()
        self.topMenu()

    def initUI(self):
        self.setWindowTitle("Lil Snippy")
        self.setWindowIcon(QtGui.QIcon("assets/lilSnippyIcon.png"))
        self.setGeometry(400, 300, 400, 300)

    def topMenu(self):
        menubar = self.menuBar()

        fileMenu = menubar.addMenu("File")
        saveAct = QtWidgets.QAction(QtGui.QIcon("assets/saveIcon.png"), "Save", self)
        saveAsAct = QtWidgets.QAction(
            QtGui.QIcon("assets/saveAsIcon.png"), "Save As", self
        )

        modeMenu = menubar.addMenu("Mode")
        snipAct = QtWidgets.QAction(QtGui.QIcon("assets/cameraIcon.png"), "Snip", self)
        snipAct.setShortcut(QtGui.QKeySequence("F1"))
        snipAct.triggered.connect(self.activateSnipping)
        videoAct = QtWidgets.QAction(QtGui.QIcon("assets/videoIcon.png"), "Video", self)
        videoAct.setShortcut("F2")
        soundAct = QtWidgets.QAction(QtGui.QIcon("assets/audioIcon.png"), "Sound", self)
        soundAct.setShortcut("F3")
        autoAct = QtWidgets.QAction(
            QtGui.QIcon("assets/automationIcon.png"), "Automation", self
        )
        autoAct.setShortcut("F4")

        helpMenu = menubar.addMenu("Help")
        helpAct = QtWidgets.QAction(QtGui.QIcon("assets/helpIcon.png"), "Help", self)
        aboutAct = QtWidgets.QAction(QtGui.QIcon("assets/aboutIcon.png"), "About", self)

        fileMenu.addAction(saveAct)
        fileMenu.addAction(saveAsAct)
        modeMenu.addAction(snipAct)
        modeMenu.addAction(videoAct)
        modeMenu.addAction(soundAct)
        modeMenu.addAction(autoAct)
        helpMenu.addAction(helpAct)
        helpMenu.addAction(aboutAct)

        self.snipper = SnippingWidget()
        self.snipper.closed.connect(self.on_closed)

    def activateSnipping(self):
        self.snipper.showFullScreen()
        self.hide()

    def on_closed(self):
        self.snipper.hide()
        self.show()


class SnippingWidget(QtWidgets.QMainWindow):
    closed = QtCore.pyqtSignal()

    def __init__(self, parent=None):
        super(SnippingWidget, self).__init__(parent)
        self.setStyleSheet("background-color: transparent;")
        self.setWindowOpacity(0.2)

        self.outsideSquareColor = "red"
        self.squareThickness = 4

        self.start_point = QtCore.QPoint()
        self.end_point = QtCore.QPoint()

    def mousePressEvent(self, event):
        self.start_point = event.pos()
        self.end_point = event.pos()
        self.update()

    def mouseMoveEvent(self, event):
        self.end_point = event.pos()
        self.update()

    def mouseReleaseEvent(self, QMouseEvent):
        r = QtCore.QRect(self.start_point, self.end_point).normalized()
        img = ImageGrab.grab(bbox=r.getCoords())
        img.save("snips/testImage.png")
        self.closed.emit()

    def paintEvent(self, event):
        qp = QtGui.QPainter(self)
        qp.setPen(
            QtGui.QPen(QtGui.QColor(self.outsideSquareColor), self.squareThickness)
        )
        trans = QtGui.QColor(255, 255, 255, 255)
        qp.setBrush(trans)

        outer = QtGui.QPainterPath()
        outer.addRect(QtCore.QRectF(self.rect()))

        inner = QtGui.QPainterPath()
        inner.addRect(QtCore.QRectF(self.start_point, self.end_point).normalized())
        r = outer - inner
        qp.drawPath(r)


if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    application = App()
    application.show()
    sys.exit(app.exec_())

更新：

class SnippingWidget(QtWidgets.QMainWindow):
    closed = QtCore.pyqtSignal()

    def __init__(self, parent=None):
        super(SnippingWidget, self).__init__(parent)
        self.setAttribute(QtCore.Qt.WA_NoSystemBackground, True)
        self.setAttribute(QtCore.Qt.WA_TranslucentBackground, True)
        self.setStyleSheet("background:transparent;")
        self.setWindowFlags(QtCore.Qt.FramelessWindowHint)

        self.outsideSquareColor = "red"
        self.squareThickness = 4

        self.start_point = QtCore.QPoint()
        self.end_point = QtCore.QPoint()

    def mousePressEvent(self, event):
        self.start_point = event.pos()
        self.end_point = event.pos()
        self.update()

    def mouseMoveEvent(self, event):
        self.end_point = event.pos()
        self.update()

    def mouseReleaseEvent(self, QMouseEvent):
        r = QtCore.QRect(self.start_point, self.end_point).normalized()
        img = ImageGrab.grab(bbox=r.getCoords())
        img.save("snips/testImage.png")
        self.closed.emit()

    def paintEvent(self, event):
        trans = QtGui.QColor(255, 255, 255)
        r = QtCore.QRectF(self.start_point, self.end_point).normalized()

        qp = QtGui.QPainter(self)
        trans.setAlphaF(0.2)
        qp.setBrush(trans)
        outer = QtGui.QPainterPath()
        outer.addRect(QtCore.QRectF(self.rect()))
        inner = QtGui.QPainterPath()
        inner.addRect(r)
        r_path = outer - inner
        qp.drawPath(r_path)

        qp.setPen(
            QtGui.QPen(QtGui.QColor(self.outsideSquareColor), self.squareThickness)
        )
        trans.setAlphaF(0)
        qp.setBrush(trans)
        qp.drawRect(r)

---

你好，eyllanesc，我感谢你愿意帮助我解决这个问题。我最初在黑色背景下尝试了你的解决方案，结果似乎奏效了。不幸的是，内部正方形不是完全透明的。在白色背景的衬托下，广场仍然有一定程度的不透明。不幸的是，这是一个外部为灰色，内部为黑色的广场。外部和内部现在都是100%不透明的。@BrettLapierre您的操作系统是什么？然后尝试删除self.setAttribute（QtCore.Qt.WA_NoSystemBackground，True）。我已经在Linux上测试过了。PyQt5 5.14.2 y Python3.8.2，它工作正常。我在windows 10上，删除该行时它仍然不工作。内部和外部仍然不透明。@BrettLapierre请尝试添加

self.setStyleSheet（“背景：透明；”）

和

self.setWindowFlags（QtCore.Qt.FramelessWindowHint）

class SnippingWidget(QtWidgets.QMainWindow):
    closed = QtCore.pyqtSignal()

    def __init__(self, parent=None):
        super(SnippingWidget, self).__init__(parent)
        self.setAttribute(QtCore.Qt.WA_NoSystemBackground, True)
        self.setAttribute(QtCore.Qt.WA_TranslucentBackground, True)
        self.setStyleSheet("background:transparent;")
        self.setWindowFlags(QtCore.Qt.FramelessWindowHint)

        self.outsideSquareColor = "red"
        self.squareThickness = 4

        self.start_point = QtCore.QPoint()
        self.end_point = QtCore.QPoint()

    def mousePressEvent(self, event):
        self.start_point = event.pos()
        self.end_point = event.pos()
        self.update()

    def mouseMoveEvent(self, event):
        self.end_point = event.pos()
        self.update()

    def mouseReleaseEvent(self, QMouseEvent):
        r = QtCore.QRect(self.start_point, self.end_point).normalized()
        img = ImageGrab.grab(bbox=r.getCoords())
        img.save("snips/testImage.png")
        self.closed.emit()

    def paintEvent(self, event):
        trans = QtGui.QColor(255, 255, 255)
        r = QtCore.QRectF(self.start_point, self.end_point).normalized()

        qp = QtGui.QPainter(self)
        trans.setAlphaF(0.2)
        qp.setBrush(trans)
        outer = QtGui.QPainterPath()
        outer.addRect(QtCore.QRectF(self.rect()))
        inner = QtGui.QPainterPath()
        inner.addRect(r)
        r_path = outer - inner
        qp.drawPath(r_path)

        qp.setPen(
            QtGui.QPen(QtGui.QColor(self.outsideSquareColor), self.squareThickness)
        )
        trans.setAlphaF(0)
        qp.setBrush(trans)
        qp.drawRect(r)