問題描述

我正在嘗試通過拖放在 PyQt5 創建的 GUI 上繪制一個矩形.我設法做到了，但是釋放鼠標左鍵時會繪制矩形.

I'm trying to draw a rectangle on GUI created by PyQt5 by drag and drop. I managed to do that, but the rectangle is drawn when the mouse left key is released.

我想做的就是這樣link:

• 按下鼠標左鍵時，開始繪制矩形.
• 拖動時，通過鼠標移動調整矩形形狀.
• 松開鼠標左鍵后，確定矩形形狀.

我該如何實現呢?提前致謝.

How can I implement this? Thanks in advance.

這是我的代碼.

# -*- coding: utf-8 -*-

import sys
from PyQt5 import QtWidgets, QtCore
from PyQt5.QtGui import QPainter

class MyWidget(QtWidgets.QWidget):
    def __init__(self):
        super().__init__()
        self.setGeometry(30,30,600,400)
        self.pos1 = [0,0]
        self.pos2 = [0,0]
        self.show()

    def paintEvent(self, event):
        width = self.pos2[0]-self.pos1[0]
        height = self.pos2[1] - self.pos1[1]     

        qp = QPainter()
        qp.begin(self)           
        qp.drawRect(self.pos1[0], self.pos1[1], width, height)        
        qp.end()

    def mousePressEvent(self, event):
        self.pos1[0], self.pos1[1] = event.pos().x(), event.pos().y()
        print("clicked")

    def mouseReleaseEvent(self, event):
        self.pos2[0], self.pos2[1] = event.pos().x(), event.pos().y()
        print("released")
        self.update()

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

推薦答案

你不必使用mouseReleaseEvent函數，而是每次調用的mouseMoveEvent函數鼠標移動了，我修改了代碼讓它更簡單.

You do not have to use the mouseReleaseEvent function, but the mouseMoveEvent function that is called each time the mouse is moved, and I have modified the code to make it simpler.

class MyWidget(QtWidgets.QWidget):
    def __init__(self):
        super().__init__()
        self.setGeometry(30,30,600,400)
        self.begin = QtCore.QPoint()
        self.end = QtCore.QPoint()
        self.show()

    def paintEvent(self, event):
        qp = QtGui.QPainter(self)
        br = QtGui.QBrush(QtGui.QColor(100, 10, 10, 40))  
        qp.setBrush(br)   
        qp.drawRect(QtCore.QRect(self.begin, self.end))       

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

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

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

這篇關于如何在 PyQt5 中通過拖放來繪制矩形并調整其形狀的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！