Python 如何强制屏幕剪大小比。PyQt5

我想修改来自的屏幕剪贴代码，以便每个屏幕剪贴的比率为3 x 2。（稍后我将另存为600 x 400像素图像）

我不知道如何动态修改

self.end

，以便用户以3 x 2的比率单击和拖动。鼠标位置将定义

x

坐标，

y

坐标将为

int（x*2/3）

有什么建议吗？我保证我一直在研究这一点，我只是不能“破解代码”，只修改

y

坐标的

self.end

代码如下：

import sys
import PyQt5
from PyQt5 import QtWidgets, QtCore, QtGui
import tkinter as tk
from PIL import ImageGrab
import numpy as np
import cv2 # package is officially called opencv-python


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, 0, screen_width, screen_height)
        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()

    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)) ##### This seems like the place I should modify. #########

    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):
        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())

        img = ImageGrab.grab(bbox=(x1, y1, x2, 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_())

您不需要“更改y坐标”，只需要使用正确的参数来创建矩形。 初始化QRect有多种方法，您可以使用两点，另一种方法（更常见的方法）是使用原点坐标和矩形大小

一旦知道了宽度，就可以计算高度，如果终点的y高于起点，则将其设为负值

请注意，通过这种方式，您可以得到一个“负”矩形（负宽度，“右”边实际上位于左侧，高度/底部相同），因此通常更好地使用它，这也允许您获得用于抓屏的矩形的正确坐标

class MyWidget(QtWidgets.QWidget):
    # ...

    def getRect(self):
        # a commodity function that always return a correctly sized
        # rectangle, with normalized coordinates
        width = self.end.x() - self.begin.x()
        height = abs(width * 2 / 3)
        if self.end.y() < self.begin.y():
            height *= -1
        return QtCore.QRect(self.begin.x(), self.begin.y(), 
            width, height).normalized()

    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(self.getRect())

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

        rect = self.getRect()
        img = ImageGrab.grab(bbox=(
            rect.topLeft().x(), 
            rect.topLeft().y(), 
            rect.bottomRight().x(), 
            rect.bottomRight().y()
        ))

        # ...

class MyWidget(QtWidgets.QWidget):
    # ...

    def showEvent(self, event):
        if not event.spontaneous():
            # delay the geometry on the "next" cycle of the Qt event loop;
            # this should take care of positioning issues for systems that
            # try to move newly created windows on their own
            QtCore.QTimer.singleShot(0, self.resetPos)

    def resetPos(self):
        rect = QtCore.QRect()
        # create a rectangle that is the sum of the geometries of all available
        # screens; the |= operator acts as `rect = rect.united(screen.geometry())`
        for screen in QtWidgets.QApplication.screens():
            rect |= screen.geometry()
        self.setGeometry(rect)