Painting background on QGraphicsView using drawBackground
<p>I have a problem trying to paint and draw on <code>QGraphicsView/Scene</code>. I'm drawing a bunch of <code>QLineF as background overriding</code>QGraphicsView::drawBackGround`. However, when I try to change the background color nothing happens.</p>

<p>Here is minimal example of what I'm doing:</p>

<pre><code>import sys
import platform
import ctypes
from PySide import QtCore, QtGui
from mygv import Ui_Dialog
import sys

class myView(QtGui.QDialog):
    def __init__(self, parent = None):
        QtGui.QDialog.__init__(self, parent)
        self.ui = Ui_Dialog()
        self.ui.setupUi(self)
        self.ui.view.drawBackground = self.drawBackground
        self.ui.view.wheelEvent = self.wheelEvent
        self.scene = QtGui.QGraphicsScene()
        self.ui.view.setScene(self.scene)
        self.scene.addEllipse(0,0,100,100)

    def drawBackground(self, painter, rect):

        bbrush = QtGui.QBrush( QtGui.QColor(255,170,255), QtCore.Qt.SolidPattern)
        painter.setBackgroundMode(QtCore.Qt.OpaqueMode)

        pen = QtGui.QPen(QtGui.QColor(46, 84, 255))
        pen.setWidth(5)
        painter.setPen(pen)

        line1 = QtCore.QLineF(0,0,0,100)
        line2 = QtCore.QLineF(0,100,100,100)
        line3 = QtCore.QLineF(100,100,100,0)
        line4 = QtCore.QLineF(100,0,0,0)
        painter.setBackground(bbrush)
        painter.drawLines([line1, line2, line3, line4])




    def wheelEvent(self,event):
        factor = 1.41 ** (event.delta() / 240.0)
        self.ui.view.scale(factor, factor)

if __name__ == '__main__':
    app = QtGui.QApplication(sys.argv)
    diag = myView()
    diag.show()
    diag.ui.view.centerOn(50,50)
    app.exec_()
</code></pre>

<p>Ui_dialog is just a standard dialog generated from QDesigner with a QGraphicsView member named "view". </p>

<p>This just an example of the problem. I need to be able to change the color of the background systematically during the execution of my app.</p>

<p>What am I missing or doing (clearly) wrong?</p>