基于pyqt的自定义QGraphicsScene支持画矩形以及返回矩形的坐标

from PyQt5 import QtCore, QtGui, QtWidgets from PyQt5.QtWidgets import QGraphicsRectItem, QGraphicsScene from PyQt5.QtCore import * from PyQt5.QtGui import * # 自定义CustomScene class CustomScene(QtWidgets.QGraphicsScene): def __init__(self, parent=None): QGraphicsScene.__init__(self, parent) self.startPoint = 0 self.endPoint = 0 self.isDrawing = False self.item = QGraphicsRectItem() self.addItem(self.item) self.pos = [] def mousePressEvent(self, event: QtWidgets.QGraphicsSceneMouseEvent) -> None: if not event.isAccepted(): if event.button() == Qt.LeftButton: point = event.scenePos() self.startPoint = point self.isDrawing = True elif event.button() == Qt.RightButton: # 检测光标下是否有item itemToRemove = None for item in self.items(event.scenePos()): if item.type() == QGraphicsRectItem.Type: itemToRemove = item break; # 从Scene上移除item if itemToRemove != None: self.removeItem(itemToRemove) def mouseMoveEvent(self, event: QtWidgets.QGraphicsSceneMouseEvent) -> None: if event.buttons() and Qt.LeftButton: point = event.scenePos() self.endPoint = point if self.endPoint.x() - self.startPoint.x() > 20 and self.endPoint.y() - self.startPoint.y() > 20: self.removeItem(self.item) p = QPen() p.setWidth(2) p.setColor(QColor(0, 0, 0)) self.item.setPen(p) self.item.setRect(self.startPoint.x(), self.startPoint.y(), self.endPoint.x()-self.startPoint.x(), self.endPoint.y()-self.startPoint.y()) self.addItem(self.item) def mouseReleaseEvent(self, event: QtWidgets.QGraphicsSceneMouseEvent) -> None: if event.button() == Qt.LeftButton: self.mouseMoveEvent(event) point = event.scenePos() self.endPoint = point pos = [(self.startPoint.x(), self.startPoint.y()), (self.endPoint.x(), self.endPoint.y())] self.pos = pos def keyPressEvent(self, event: QtGui.QKeyEvent) -> None: if event.key() == Qt.Key_Backspace: while not self.selectedItems().isEmpty(): self.removeItem(self.selectedItems().front()) else: self.keyPressEvent(event) def rtnPos(self): return self.pos