在两个Qgraphicscene之间的拖动和滴度期间，如何在鼠标下方创建项目覆盖层？

Question

我正在尝试创建两个Qgraphicscene，可以在其中我可以从左场景中拖动一个项目并将其放在Rigth场景中。我成功地制作了drad和drop，但是我不明白如何在阻力过程中创建SVG项目的覆盖层。我想拥有的是至少显示鼠标在Rigth场景上时的覆盖层。

到目前为止，我有此代码：

import sys
from PyQt5.QtGui import *
from PyQt5.QtCore import *
from PyQt5.QtWidgets import *
from PyQt5.QtSvg import QGraphicsSvgItem


class myQGraphicsScene(QGraphicsScene):
    def __init__(self,parent=None):
        super(myQGraphicsScene, self).__init__()
        self.parent = parent

    def dragEnterEvent(self, event):
        event.accept()

    def dragMoveEvent(self, event):
        event.accept()

    def dragLeaveEvent(self, event):
        event.accept()

    def dropEvent(self, event):
        text = event.mimeData().text()
        item = self.parent.getSelecedItemfromname(text)
        br = item.boundingRect()
        s = item.scale()
        w = int(br.width() * s)/2
        h = int(br.height() * s)/2
        pos = event.scenePos()
        item.setPos(pos - QPointF(w,h))
        self.addItem(item)
        event.accept()


class myQGraphicsScene2(QGraphicsScene):
    def __init__(self, parent=None):
        super(myQGraphicsScene2, self).__init__()
        self.parent = parent

    def dragEnterEvent(self, event):
        event.setDropAction(Qt.MoveAction)
        event.accept()

    def startDrag(self, event):
        item = self.itemAt(event.scenePos(), QTransform())
        print(item)
        if item is None:
            return

        # selected = self.model().data(item, Qt.DisplayRole)
        name = self.parent.getSelecedNamefromitem(item)
        mimeData = QMimeData()
        mimeData.setText(name )

        drag = QDrag(self)
        drag.setMimeData(mimeData)

        result = drag.exec(Qt.MoveAction)
        if result:  # == Qt.MoveAction:
            pass

    def mouseMoveEvent(self, event):
        self.startDrag(event)


class MainWindow(QMainWindow):

    def __init__(self):
        super().__init__()
        self.setMouseTracking(True)
        self.names = ['fjJ.svg','fjJ.svg','fjJ.svg']
        self. items = []
        shift = 200
        for i, n in enumerate(self.names):
            item = QGraphicsSvgItem(n)
            # item.setFlag(QGraphicsItem.ItemIsMovable)
            item.setFlag(not QGraphicsItem.ItemIsMovable)
            # item.setFlag(QGraphicsItem.ItemIsSelectable)
            item.setScale(0.25)
            item.setPos(0, i * shift)
            self.items.append(item)

        self.scene = myQGraphicsScene2(self)
        for i in self.items:
            self.scene.addItem(i)

        self.scene2 = myQGraphicsScene(self)

        self.view = QGraphicsView()
        self.view.setScene(self.scene)
        self.view2 = QGraphicsView()
        self.view2.setMouseTracking(True)
        self.view2.setScene(self.scene2)

        HBOX = QHBoxLayout()
        HBOX.addWidget(self.view)
        HBOX.addWidget(self.view2)
        widget = QWidget()
        widget.setLayout(HBOX)
        self.setCentralWidget(widget)
        self.setFixedSize(QSize(800,600))

    def getSelecedItem(self):
        item = -1
        for k, i in enumerate(self.items):
            if i.isSelected():
                item = k
        if not item == -1:
            new_item = QGraphicsSvgItem(self.names[item])
            new_item.setFlag(QGraphicsItem.ItemIsMovable)
            new_item.setScale(0.25)
            return new_item
        else:
            return None
    def getSelecedNamefromitem(self,itemfrom):
        item = -1
        for k, i in enumerate(self.items):
            if i == itemfrom:
                item = k
        if not item == -1:
            return self.names[k]
        else:
            return None

    def getSelecedItemfromname(self,name):
        item = -1
        for k, n  in enumerate(self.names):
            if n == name:
                item = k
        if not item == -1:
            new_item = QGraphicsSvgItem(self.names[item])
            new_item.setFlag(QGraphicsItem.ItemIsMovable)
            new_item.setScale(0.25)
            return new_item
        else:
            return None

    def getSelecedName(self):
        item = -1
        for k, i in enumerate(self.items):
            if i.isSelected():
                item = k
        if not item == -1:
            return self.names[item]
        else:
            return None
 

if __name__ == '__main__':
    app = QApplication(sys.argv)
    w = MainWindow()
    w.show()
    app.exec()

这里.svg https://svgshare.com/i/fjj..svg

Answer 1

我自己找到了解决方案。它不是完美的，但它确实有效。您可以放置​​其他更优化的解决方案。

import sys
from PyQt5.QtGui import *
from PyQt5.QtCore import *
from PyQt5.QtWidgets import *
from PyQt5.QtSvg import QGraphicsSvgItem


class myQGraphicsScene(QGraphicsScene):
    def __init__(self,parent=None):
        super(myQGraphicsScene, self).__init__()
        self.parent = parent

    def dragEnterEvent(self, event):
        print('dragEnterEvent')
        event.accept()

    def dragMoveEvent(self, event):
        print('dragMoveEvent')
        event.accept()

    def dragLeaveEvent(self, event):
        print('dragLeaveEvent')
        event.accept()

    def dropEvent(self, event):
        text = event.mimeData().text()
        item = self.parent.getSelecedItemfromname(text)
        br = item.boundingRect()
        s = item.scale()
        w = int(br.width() * s)/2
        h = int(br.height() * s)/2
        pos = event.scenePos()
        item.setPos(pos - QPointF(w,h))
        self.addItem(item)
        event.accept()


class myQGraphicsScene2(QGraphicsScene):
    def __init__(self, parent=None):
        super(myQGraphicsScene2, self).__init__()
        self.parent = parent

    def dragEnterEvent(self, event):
        event.setDropAction(Qt.MoveAction)
        event.accept()

    def startDrag(self, event):
        item = self.itemAt(event.scenePos(), QTransform())
        print(item)
        if item is None:
            return

        # # selected = self.model().data(item, Qt.DisplayRole)
        name = self.parent.getSelecedNamefromitem(item)
        # mimeData = QMimeData()
        # mimeData.setText(name )
        #
        # drag = QDrag(self)
        # drag.setMimeData(mimeData)
        #
        # result = drag.exec(Qt.MoveAction)
        # if result:  # == Qt.MoveAction:
        #     pass

        pixmap = self.parent.getSelecedimagefromname(name)
        drag = QDrag(self)
        mimedata = QMimeData()
        mimedata.setText(name)
        mimedata.setImageData(pixmap.toImage())

        drag.setMimeData(mimedata)
        painter = QPainter(pixmap)
        painter.drawPixmap(pixmap.rect(), pixmap)
        painter.end()
        drag.setPixmap(pixmap)
        # drag.setHotSpot(QPoint(event.scenePos().x(),event.scenePos().y()))
        drag.setHotSpot(QPoint((pixmap.size()/2).width(),(pixmap.size()/2).height()))
        drag.exec_(Qt.CopyAction | Qt.MoveAction)

    def mouseMoveEvent(self, event):
        self.startDrag(event)


class MainWindow(QMainWindow):

    def __init__(self):
        super().__init__()
        self.setMouseTracking(True)
        self.names = ['function.svg','multiply.svg','minus.svg']
        self.items = []
        shift = 200
        for i, n in enumerate(self.names):
            item = QGraphicsSvgItem(n)
            # item.setFlag(QGraphicsItem.ItemIsMovable)
            item.setFlag(not QGraphicsItem.ItemIsMovable)
            # item.setFlag(QGraphicsItem.ItemIsSelectable)
            item.setScale(0.25)
            item.setPos(0, i * shift)
            self.items.append(item)

        self.scene = myQGraphicsScene2(self)
        for i in self.items:
            self.scene.addItem(i)

        self.scene2 = myQGraphicsScene(self)

        self.view = QGraphicsView()
        self.view.setScene(self.scene)
        self.view2 = QGraphicsView()
        self.view2.setMouseTracking(True)
        self.view2.setScene(self.scene2)
        self.view2.setFixedSize(QSize(400,600))
        self.view2.setSceneRect(0,0,400,600)
        # self.view2.setTransformationAnchor(QGraphicsView.NoAnchor)
        # self.view2.setResizeAnchor(QGraphicsView.NoAnchor)

        HBOX = QHBoxLayout()
        HBOX.addWidget(self.view)
        HBOX.addWidget(self.view2)
        widget = QWidget()
        widget.setLayout(HBOX)
        self.setCentralWidget(widget)
        # self.setFixedSize(QSize(800,600))

    def getSelecedItem(self):
        item = -1
        for k, i in enumerate(self.items):
            if i.isSelected():
                item = k
        if not item == -1:
            new_item = QGraphicsSvgItem(self.names[item])
            new_item.setFlag(QGraphicsItem.ItemIsMovable)
            new_item.setScale(0.25)
            return new_item
        else:
            return None
    def getSelecedNamefromitem(self,itemfrom):
        item = -1
        for k, i in enumerate(self.items):
            if i == itemfrom:
                item = k
        if not item == -1:
            return self.names[item]
        else:
            return None

    def getSelecedItemfromname(self,name):
        item = -1
        for k, n  in enumerate(self.names):
            if n == name:
                item = k
        if not item == -1:
            new_item = QGraphicsSvgItem(self.names[item])
            new_item.setFlag(QGraphicsItem.ItemIsMovable)
            new_item.setScale(0.25)
            return new_item
        else:
            return None

    def getSelecedimagefromname(self,name):
        item = -1
        for k, n  in enumerate(self.names):
            if n == name:
                item = k
        if not item == -1:
            new_item =  QIcon(self.names[item]).pixmap(self.items[item].boundingRect().size().toSize() * self.items[item].scale())
            return new_item
        else:
            return None

    def getSelecedName(self):
        item = -1
        for k, i in enumerate(self.items):
            if i.isSelected():
                item = k
        if not item == -1:
            return self.names[item]
        else:
            return None


if __name__ == '__main__':
    app = QApplication(sys.argv)
    w = MainWindow()
    w.show()
    app.exec()