我在使用 QGraphicsView
和 QGraphicsScene
时遇到了一些困难。
当我在场景中缩放/取消缩放并使用 mousePressEvent 创建项目时,我在该位置有一个偏移量。如何避免这种情况?
event.pos()
似乎是问题所在..
from PyQt4 import QtCore, QtGui
class graphicsItem (QtGui.QGraphicsItem):
def __init__ (self):
super(graphicsItem, self).__init__()
self.rectF = QtCore.QRectF(0,0,10,10)
def boundingRect (self):
return self.rectF
def paint (self, painter=None, style=None, widget=None):
painter.fillRect(self.rectF, QtCore.Qt.red)
class graphicsScene (QtGui.QGraphicsScene):
def __init__ (self, parent=None):
super (graphicsScene, self).__init__ (parent)
class graphicsView (QtGui.QGraphicsView):
def __init__ (self, parent = None):
super (graphicsView, self).__init__ (parent)
self.parent = parent
def mousePressEvent(self, event):
super (graphicsView, self).mousePressEvent(event)
item = graphicsItem()
position = QtCore.QPointF(event.pos()) - item.rectF.center()
item.setPos(position.x() , position.y())
self.parent.scene.addItem(item)
def wheelEvent (self, event):
super (graphicsView, self).wheelEvent(event)
factor = 1.2
if event.delta() < 0 :
factor = 1.0 / factor
self.scale(factor, factor)
class window (QtGui.QMainWindow):
def __init__ (self, parent = None ) :
super (window, self).__init__(parent)
self.width = 800
self.height = 600
self.resize(self.width,self.height)
self.mainLayout = QtGui.QVBoxLayout(self)
self.view = graphicsView(self)
self.scene = graphicsScene(self)
self.view.setScene (self.scene)
factor = 1
self.scene.setSceneRect(0, 0, self.width * factor, self.height * factor)
self.view.setMinimumSize(self.width, self.height)
self.mainLayout.addWidget(self.view)
def show (self):
super (window, self).show()
最佳答案
在场景而不是 View 上重新实现 mousePressEvent
。
这样,event
参数将是一个 QGraphicsSceneMouseEvent
,它有几个有用的附加功能 - 包括 scenePos
,这正是你想要的:
class graphicsScene(QtGui.QGraphicsScene):
def __init__ (self, parent=None):
super(graphicsScene, self).__init__ (parent)
def mousePressEvent(self, event):
super(graphicsScene, self).mousePressEvent(event)
item = graphicsItem()
position = QtCore.QPointF(event.scenePos()) - item.rectF.center()
item.setPos(position.x() , position.y())
self.addItem(item)
关于python - MousePressEvent,QGraphicsView中的位置偏移,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/12249875/