在 Python 中从 Snipping_Tool 中选择屏幕 2

问题描述

我正在使用与 SnippingTool 类似的工具：https://github.com/harupy/snipping-tool。
我有 2 个屏幕，我想知道如何从屏幕 2 抓取图片，因为我的代码只从屏幕 1 捕获图片，即使我在屏幕 2 中设置了几何图形。
我的主屏幕 (#1) 是底部屏幕，我的辅助屏幕 (#2) 是顶部屏幕。
屏幕的配置是多显示器和扩展显示器。两种分辨率均为 1920 x 1080。
我想知道如何选择不同的屏幕以及是否可以从两个屏幕一起捕获。
下面是我的代码：

import sys
from PyQt5 import QtWidgets,QtCore,QtGui
import tkinter as tk
from PIL import ImageGrab
import numpy as np
import cv2

class MyWidget(QtWidgets.QWidget):
    def __init__(self):
        super().__init__()
        root = tk.Tk()
        screen_width = root.winfo_screenwidth()
        screen_height = root.winfo_screenheight()

        # self.setGeometry(0,screen_width,screen_height) # Geometry for Screen 1 - bottom)
        self.setGeometry(0,-1080,screen_height) # Geometry for Screen 2 - top)

        self.setwindowTitle(' ')
        self.begin = QtCore.QPoint()
        self.end = QtCore.QPoint()
        self.setwindowOpacity(0.3)
        QtWidgets.QApplication.setoverrideCursor(
            QtGui.QCursor(QtCore.Qt.CrossCursor)
        )
        self.setwindowFlags(QtCore.Qt.FramelessWindowHint)
        print('Capture the screen...')
        self.show()
        print(screen_width,screen_height)

    def paintEvent(self,event):
        qp = QtGui.QPainter(self)
        qp.setPen(QtGui.QPen(QtGui.QColor('black'),3))
        qp.setBrush(QtGui.QColor(128,128,255,128))
        qp.drawRect(QtCore.QRect(self.begin,self.end))

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

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

    def mouseReleaseEvent(self,event):
        self.close()

        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())

        # (x1,y1,x2,y2) = (268,-749,941,-631)

        print(x1,y2)
        
        img = ImageGrab.grab(bBox=(x1,y2))
        img.save('capture.png')
        img = cv2.cvtColor(np.array(img),cv2.COLOR_BGR2RGB)

        cv2.imshow('Captured Image',img)
        cv2.waitKey(0)
        cv2.destroyAllWindows()

if __name__ == '__main__':
    app = QtWidgets.QApplication(sys.argv)
    window = MyWidget()
    window.show()
    app.aboutToQuit.connect(app.deleteLater)
    sys.exit(app.exec_())

解决方法

问题是 event.pos() 是相对于小部件的坐标系，而不是屏幕。一种可能的解决方案是使用 mapToGlobal 将其转换为全局坐标：

def mouseReleaseEvent(self,event):
    super().mouseReleaseEvent(event)
    self.close()
    self.end = event.pos()

    rect = QtCore.QRect(
        self.mapToGlobal(self.begin),self.mapToGlobal(self.end)
    ).normalized()
    x1,y1,x2,y2 = rect.getCoords()

    img = ImageGrab.grab(bbox=(x1,y2))
    img.save("capture.png")
    img = cv2.cvtColor(np.array(img),cv2.COLOR_BGR2RGB)

    cv2.imshow("Captured Image",img)
    cv2.waitKey(0)
    cv2.destroyAllWindows()

注意：我没有测试过 img = ImageGrab.grab(bbox=(x1,y2)) 部分，所以我不知道 ImageGrab 库是否支持多个窗口。

---

Qt 解决方案：

另一方面，我认为没有必要使用第三个库，因为 Qt 可以截取屏幕截图：

import sys
from PyQt5 import QtCore,QtGui,QtWidgets


class MyWidget(QtWidgets.QWidget):
    def __init__(self):
        super().__init__()
        self.setWindowTitle(" ")
        self.begin = QtCore.QPoint()
        self.end = QtCore.QPoint()

        self.setWindowOpacity(0.3)

        QtWidgets.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.CrossCursor))
        self.setWindowFlags(QtCore.Qt.FramelessWindowHint)
        print("Capture the screen...")

        self.showFullScreen()

    def paintEvent(self,event):
        qp = QtGui.QPainter(self)
        qp.setPen(QtGui.QPen(QtGui.QColor("black"),3))
        qp.setBrush(QtGui.QColor(128,128,255,128))
        qp.drawRect(QtCore.QRect(self.begin,self.end))

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

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

    def mouseReleaseEvent(self,event):
        self.close()
        QtCore.QTimer.singleShot(1000,self.screenshot)

    def screenshot(self):
        print("screenshot")
        screen = QtGui.QGuiApplication.primaryScreen()
        window = self.windowHandle()
        if window is not None:
            screen = window.screen()
        if screen is None:
            print("failed")
            return

        original_pixmap = screen.grabWindow(0)
        output_pixmap = original_pixmap.copy(
            QtCore.QRect(self.begin,self.end).normalized()
        )
        output_pixmap.save("capture.png")

        self.label = QtWidgets.QLabel(pixmap=output_pixmap)
        self.label.show()
        app.setQuitOnLastWindowClosed(True)


if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    window = MyWidget()
    window.show()
    app.aboutToQuit.connect(app.deleteLater)
    app.setQuitOnLastWindowClosed(False)
    sys.exit(app.exec_())