我使用pyqt4.8和python2.7

我創(chuàng)建QGraphicsView并插入QGraphicsScene.比View更大的場(chǎng)景,需要滾動(dòng).視圖有垂直和水平滾動(dòng),但我想通過(guò)鼠標(biāo)中鍵滾動(dòng).

我創(chuàng)建鼠標(biāo)事件功能,但運(yùn)動(dòng)到奇怪.

def mousePressEvent(self, event):

self.__mousePressPos = None

self.__mouseMovePos = None

if event.button() == Qt.MidButton:

self.__mousePressPos = event.globalPos()

self.__mouseMovePos = event.globalPos()

else:

super(MyView, self).mousePressEvent(event)

def mouseMoveEvent(self, event):

if event.buttons() == Qt.MidButton:

curPos = self.__mousePressPos - self.__mouseMovePos

self.centerOn(curPos.x(), curPos.y())

self.__mouseMovePos = globalPos

else:

super(MyView, self).mouseMoveEvent(event)

def mouseReleaseEvent(self, event):

if self.__mousePressPos is not None:

moved = event.globalPos() - self.__mousePressPos

if moved.manhattanLength() > 3:

event.ignore()

return

super(MyView, self).mouseReleaseEvent(event)

首先,場(chǎng)景移動(dòng)與鼠標(biāo)的移動(dòng)不對(duì)應(yīng).我懷疑是視口的相對(duì)大小和場(chǎng)景的責(zé)任.以及舞臺(tái)的規(guī)模.

其次,我無(wú)法移動(dòng)視口外的場(chǎng)景,它到達(dá)邊緣時(shí)停止.

讓第二個(gè)仍然可以容忍.讓它保持原樣,但如何計(jì)算正確移動(dòng)的場(chǎng)景的正確偏移移動(dòng)鼠標(biāo),無(wú)論它被捕獲的位置？

解決方法:

我的解決方案不是調(diào)用centerOn方法,而是使用QGraphicView的滾動(dòng)條：

class MyView(QtGui.QGraphicsView):

def mousePressEvent(self, event):

if event.button() == Qt.MidButton: # or Qt.MiddleButton

self.__prevMousePos = event.pos()

else:

super(MyView, self).mousePressEvent(event)

def mouseMoveEvent(self, event):

if event.buttons() == Qt.MidButton: # or Qt.MiddleButton

offset = self.__prevMousePos - event.pos()

self.__prevMousePos = event.pos()

self.verticalScrollBar().setValue(self.verticalScrollBar().value() + offset.y())

self.horizontalScrollBar().setValue(self.horizontalScrollBar().value() + offset.x())

else:

super(MyView, self).mouseMoveEvent(event)

標(biāo)簽：qgraphicsview,python,pyqt,mouseevent,qgraphicsscene

來(lái)源： https://codeday.me/bug/20190824/1709005.html

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