ScreenCapture.py

from PyQt5 import QtCore, QtGui
from PIL import ImageGrab
from PyQt5.QtWidgets import QApplication, QWidget, QMainWindow


class SnippingWidget(QMainWindow):
    capture_done = 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 = 1

        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()
        self.hide()
        img = ImageGrab.grab(bbox=r.getCoords())
        img.save("asset/testImage.png")
        QApplication.restoreOverrideCursor()
        self.start_point = QtCore.QPoint()
        self.end_point = QtCore.QPoint()
        self.capture_done.emit()
        self.close()

    def paintEvent(self, event):
        trans = QtGui.QColor(22, 100, 233)
        r = QtCore.QRectF(self.start_point, self.end_point).normalized()
        qp = QtGui.QPainter(self)
        trans.setAlphaF(0.1)
        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)