Pyqt 截取某个屏幕区域的截图 [英] Pyqt take screenshot of certain screen area

问题描述

我用 pyqt 编写了这个应用程序.您可以在

I have this app written in pyqt. You can view the source at http://www.pasteall.org/62739/python It takes screen shots of the desktop. what I want to know is how to make it also take a screen shot of a certain area on the screen like window's snipping tool can do (http://sjcblogs.sanjac.edu/its/files/2011/09/Snipping-Tool-selection-types1.jpg and gilsmethod.wpengine.netdna-cdn.com/images/snipping-tool-windows-73.png). How do I write this?

Thank you in advance!

解决方案

Install following packages:

pip install pillow opencv-python pyside2

Run the following code:

import sys

from PySide2.QtCore import *
from PySide2.QtGui import *
from PySide2.QtWidgets import *

import numpy as np
import cv2
from PIL import ImageGrab

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        if not MainWindow.objectName():
            MainWindow.setObjectName(u"MainWindow")
        MainWindow.resize(1000, 1000)
        sizePolicy = QSizePolicy(QSizePolicy.Maximum, QSizePolicy.Maximum)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(MainWindow.sizePolicy().hasHeightForWidth())
        MainWindow.setSizePolicy(sizePolicy)
        MainWindow.setMinimumSize(QSize(1000, 1000))
        MainWindow.setMaximumSize(QSize(16777215, 16777215))
        MainWindow.setTabShape(QTabWidget.Rounded)
        self.centralwidget = QWidget(MainWindow)
        self.centralwidget.setObjectName(u"centralwidget")
        sizePolicy1 = QSizePolicy(QSizePolicy.Preferred, QSizePolicy.Preferred)
        sizePolicy1.setHorizontalStretch(0)
        sizePolicy1.setVerticalStretch(0)
        sizePolicy1.setHeightForWidth(self.centralwidget.sizePolicy().hasHeightForWidth())
        self.centralwidget.setSizePolicy(sizePolicy1)
        self.centralwidget.setMinimumSize(QSize(1000, 1000))
        self.gridLayout = QGridLayout(self.centralwidget)
        self.gridLayout.setObjectName(u"gridLayout")
        self.pushButton_area = QPushButton(self.centralwidget)
        self.pushButton_area.setObjectName(u"pushButton_area")
        self.pushButton_area.setMinimumSize(QSize(800, 0))

        self.gridLayout.addWidget(self.pushButton_area, 0, 0, 1, 1)

        self.label = QLabel(self.centralwidget)
        self.label.setObjectName(u"label")
        sizePolicy2 = QSizePolicy(QSizePolicy.Expanding, QSizePolicy.Expanding)
        sizePolicy2.setHorizontalStretch(0)
        sizePolicy2.setVerticalStretch(0)
        sizePolicy2.setHeightForWidth(self.label.sizePolicy().hasHeightForWidth())
        self.label.setSizePolicy(sizePolicy2)
        self.label.setMinimumSize(QSize(800, 800))
        self.label.setMaximumSize(QSize(4096, 4096))

        self.gridLayout.addWidget(self.label, 2, 0, 2, 1)

        self.pushButton_full = QPushButton(self.centralwidget)
        self.pushButton_full.setObjectName(u"pushButton_full")
        self.pushButton_full.setMinimumSize(QSize(800, 0))

        self.gridLayout.addWidget(self.pushButton_full, 1, 0, 1, 1)

        MainWindow.setCentralWidget(self.centralwidget)

        self.retranslateUi(MainWindow)

        QMetaObject.connectSlotsByName(MainWindow)

    def retranslateUi(self, MainWindow):
        MainWindow.setWindowTitle(QCoreApplication.translate("MainWindow", u"Snipping Tool", None))
        MainWindow.setAccessibleName(QCoreApplication.translate("MainWindow", u"Snipping Tool", None))
        self.pushButton_area.setText(QCoreApplication.translate("MainWindow", u"Select Area", None))
        self.pushButton_full.setText(QCoreApplication.translate("MainWindow", u"Fullscreen", None))

# Refer to https://github.com/harupy/snipping-tool
class SnippingWidget(QWidget):
    is_snipping = False

    def __init__(self, parent=None, app=None):
        super(SnippingWidget, self).__init__()
        self.parent = parent
        self.setWindowFlags(Qt.WindowStaysOnTopHint)

        self.screen = app.primaryScreen()
        self.setGeometry(0, 0, self.screen.size().width(), self.screen.size().height())
        self.begin = QPoint()
        self.end = QPoint()
        self.onSnippingCompleted = None

    def fullscreen(self):
        img = ImageGrab.grab(bbox=(0, 0, self.screen.size().width(), self.screen.size().height()))

        try:
            img = cv2.cvtColor(np.array(img), cv2.COLOR_RGB2BGR)
        except:
            img = None
            
        if self.onSnippingCompleted is not None:
            self.onSnippingCompleted(img)

    def start(self):
        SnippingWidget.is_snipping = True
        self.setWindowOpacity(0.3)
        QApplication.setOverrideCursor(QCursor(Qt.CrossCursor))
        self.show()

    def paintEvent(self, event):
        if SnippingWidget.is_snipping:
            brush_color = (128, 128, 255, 100)
            lw = 3
            opacity = 0.3
        else:
            self.begin = QPoint()
            self.end = QPoint()
            brush_color = (0, 0, 0, 0)
            lw = 0
            opacity = 0

        self.setWindowOpacity(opacity)
        qp = QPainter(self)
        qp.setPen(QPen(QColor('black'), lw))
        qp.setBrush(QColor(*brush_color))
        rect = QRectF(self.begin, self.end)
        qp.drawRect(rect)

    def mousePressEvent(self, event):
        self.begin = event.pos()
        self.end = self.begin
        self.update()

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

    def mouseReleaseEvent(self, event):
        SnippingWidget.is_snipping = False
        QApplication.restoreOverrideCursor()
        x1 = min(self.begin.x(), self.end.x())
        y1 = min(self.begin.y(), self.end.y())
        x2 = max(self.begin.x(), self.end.x())
        y2 = max(self.begin.y(), self.end.y())

        self.repaint()
        QApplication.processEvents()
        img = ImageGrab.grab(bbox=(x1, y1, x2, y2))

        try:
            img = cv2.cvtColor(np.array(img), cv2.COLOR_RGB2BGR)
        except:
            img = None
            
        if self.onSnippingCompleted is not None:
            self.onSnippingCompleted(img)

        self.close()

class MainWindow(QMainWindow):
    useQThread = True

    def __init__(self):
        super(MainWindow, self).__init__()
        self.ui = Ui_MainWindow()
        self.ui.setupUi(self)
        self.setAcceptDrops(True)

        self.snippingWidget = SnippingWidget(app=QApplication.instance())
        self.snippingWidget.onSnippingCompleted = self.onSnippingCompleted
        self.ui.pushButton_area.clicked.connect(self.snipArea)
        self.ui.pushButton_full.clicked.connect(self.snipFull)

        self._pixmap = None

    def onSnippingCompleted(self, frame):
        self.setWindowState(Qt.WindowActive)
        if frame is None:
            return 

        image = QImage(frame, frame.shape[1], frame.shape[0], frame.strides[0], QImage.Format_RGB888)
        pixmap = QPixmap.fromImage(image)
        self._pixmap = self.resizeImage(pixmap)
        self.ui.label.setPixmap(self._pixmap)

    def snipArea(self):
        self.setWindowState(Qt.WindowMinimized)
        self.snippingWidget.start()    

    def snipFull(self):
        self.setWindowState(Qt.WindowMinimized)
        self.snippingWidget.fullscreen()    

    def dragEnterEvent(self, event):
        event.acceptProposedAction()

    def dropEvent(self, event):
        urls = event.mimeData().urls()
        filename = urls[0].toLocalFile()
        self.loadFile(filename)
        self.decodeFile(filename)
        event.acceptProposedAction()

    def resizeImage(self, pixmap):
        lwidth = self.ui.label.width()
        pwidth = pixmap.width()
        lheight = self.ui.label.height()
        pheight = pixmap.height()

        wratio = pwidth * 1.0 / lwidth
        hratio = pheight * 1.0 / lheight

        if pwidth > lwidth or pheight > lheight:
            if wratio > hratio:
                lheight = pheight / wratio
            else:
                lwidth = pwidth / hratio

            scaled_pixmap = pixmap.scaled(lwidth, lheight)
            return scaled_pixmap
        else:
            return pixmap

    def showMessageBox(self, title, content):
        msgBox = QMessageBox()
        msgBox.setWindowTitle(title)
        msgBox.setText(content)
        msgBox.exec_()

    def closeEvent(self, event):
    
        msg = "Close the app?"
        reply = QMessageBox.question(self, 'Message', 
                        msg, QMessageBox.Yes, QMessageBox.No)

        if reply == QMessageBox.Yes:
            event.accept()
        else:
            event.ignore()

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

if __name__ == '__main__':
    main()

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