如何擦除/删除QGraphicPathItem的特定部分？

class GraphicsSceneClass(QGraphicsScene): def __init__(self): super().__init__() self.setItemIndexMethod(QGraphicsScene.NoIndex) self.setBackgroundBrush(QBrush(Qt.black)) self.setSceneRect(0,0,1000,1000) self.horizontal=QHBoxLayout() self.widget=QWidget() self.drawrect=False self.gridOn = 0 self.selectionMode = 1 self.targetForLine = QRect() self.drawEnd = True self.resizemode=0 self.eraser_item = None self.erasing=False self.rect=QGraphicsRectItem() def mousePressEvent(self,event): try: sampleTransform = QTransform() self.objectAtMouse = self.itemAt(event.scenePos(), sampleTransform) if self.selectionMode == 2: if self.drawEnd == True: self.drawEnd = False elif self.drawEnd == False: self.drawEnd = True self.drawLineObj = None if self.drawEnd == False: self.lineInsertPoint = self.TargPosForLine(event.scenePos(), "ForLine") tempPainterPath = QPainterPath() self.drawLineObj = QGraphicsPathItem() self.drawLineObj.setPos(self.lineInsertPoint.x(), self.lineInsertPoint.y()) self.drawLineObj.setPen(QPen(Qt.NoPen)) self.drawLineObj.setBrush(QBrush(QColor(Qt.gray))) self.drawLineObj.setPath(tempPainterPath) self.addItem(self.drawLineObj) self.drawLineObj.setFlag(QGraphicsItem.ItemIsSelectable) if event.buttons() == Qt.RightButton and self.resizemode == 1: self.erasing = True self.rect.setRect(event.scenePos().x()-5, event.scenePos().y()-5, 10, 10) print(event.pos().x(),event.pos().y()) self.addItem(self.rect) self.rect.setPen(QColor(Qt.red)) except Exception as e: print("Error in mousepress",e) def mouseMoveEvent(self,event): try: if self.selectionMode == 2 and self.drawEnd == False and self.erasing == False: f1 = QPainterPath() gridPos = self.TargPosForLine(event.scenePos(), "ForLine") f1.moveTo(0, 0) f1.lineTo(0, 6) f1.lineTo((gridPos.x() - self.lineInsertPoint.x()), 6) f1.lineTo((gridPos.x() - self.lineInsertPoint.x()), 0) f1.closeSubpath() self.drawLineObj.setPath(f1) self.drawLineObj.setPos(self.lineInsertPoint.x(), self.lineInsertPoint.y() + 5) self.drawLineObj.setBrush(QBrush(QColor(Qt.gray))) pen = QPen(QColor(Qt.gray)) pen.setWidth(0) self.drawLineObj.setPen(pen) self.drawLineObj._property = [] self.drawLineObj._angle = 0 if self.selectionMode == 2 and self.drawEnd == True: self.targetForLine = self.TargPosForLine(event.scenePos(), "ForRect") self.update() if event.buttons() & Qt.RightButton and self.erasing: print(event.scenePos().x(),event.scenePos().y()) self.rect.setRect(event.scenePos().x() - 5, event.scenePos().y() - 5, 10, 10) for item in self.collidingItems(self.rect): new = item.path()-(self.rect.shape()) item.setPath(new) print('collided') else: self.targetForLine = QRect() except Exception as e: print("Error in mousemove",e) def mouseReleaseEvent(self, event): if self.drawrect==True or self.tLext==2 or self.tRext==2 or self.BLext==2 or self.BRext==2: self.drawrect=False self.tLext=0 self.tRext=0 self.BLext=0 self.BRext=0 QApplication.changeOverrideCursor(Qt.ArrowCursor) QApplication.setOverrideCursor(Qt.ArrowCursor) mainWindow.pointer.setChecked(False) if self.rect != None: self.removeItem(self.rect) def TargPosForLine(self, position, mode): try: clicked_column = int((position.y() // 16)) * 16 clicked_row = int((position.x() // 16)) * 16 if clicked_column < 0: clicked_column = 0 if clicked_row < 0: clicked_row = 0 if (mode == "ForRect"): return QRect(clicked_row, clicked_column, 16, 16) elif (mode == "ForLine"): return QPointF(clicked_row, clicked_column) except Exception as e: print("Error in TargPosForLine", e) class MainWindow(QMainWindow): def __init__(self): super().__init__() self.scene = GraphicsSceneClass() self.view=QGraphicsView(self.scene) self.view.setMouseTracking(True) self.view.setAcceptDrops(True) self.view.setRenderHint(QPainter.HighQualityAntialiasing) self.linePointerButton = QToolButton() self.linePointerButton.setCheckable(True) self.linePointerButton.setText("Drawline") self.linePointerButton.setToolTip("Draw Track") self.linePointerButton.clicked.connect(self.setPointerMode) self.resizebutton = QToolButton() self.resizebutton.setText("Resize") self.resizebutton.setCheckable(True) self.resizebutton.clicked.connect(self.resizepath) self.widg=QWidget() self.horizontal=QHBoxLayout() self.horizontal.addWidget(self.view) self.widg.setLayout(self.horizontal) self.setCentralWidget(self.widg) self.tool=self.addToolBar("Tool") self.tool.addWidget(self.linePointerButton) self.tool.addWidget(self.resizebutton) def keyPressEvent(self, event): try: key = event.key() if key == Qt.Key_Escape: but = self.linePointerButton self.scene.selectionMode = 1 but.setChecked(True) except Exception: print("Keypress is not working") def setPointerMode(self): try: self.scene.selectionMode =2 except Exception: print("Not able to change the selectionmode") def resizepath(self): self.scene.resizemode=1 self.scene.selectionMode = 1 self.linePointerButton.setChecked(False) if __name__=="__main__": import sys app=QApplication(sys.argv) mainWindow = MainWindow() mainWindow.show() sys.exit(app.exec_())

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1楼 · 发布于 2024-05-19 05:53:04

路径和item以及来自self.rect的形状不共享相同的坐标系。因此，当您要从线rect中删除橡皮擦时，必须使用公共坐标系（例如，您的场景之一）：

for item in self.collidingItems(self.rect):
                    new = item.mapToScene(item.path())-self.rect.mapToScene(self.rect.shape()) # translate the paths to the scene coords system
                    item.setPath(item.mapFromScene(new)) # translate the path from the scene coords system

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