import sys
from PyQt4 import QtGui
from PyQt4 import QtCore


class Paintar(QtGui.QWidget):
    def __init__(self, parent=None):
        QtGui.QWidget.__init__(self, parent)
        self.resize(300, 300)

    def paintEvent(self, event):
        painter = QtGui.QPainter(self)
        if not painter.isActive():
            painter.begin(self)

        painter.fillRect(self.rect(),
                         QtGui.QBrush(QtGui.QColor('white')))


        painter.fillRect(self.rect(),
                         QtGui.QBrush(QtGui.QColor('#09f'),
                                      QtCore.Qt.CrossPattern))
        painter.end()


if __name__ == '__main__':
    app = QtGui.QApplication(sys.argv)
    lol = Paintar()
    lol.show()
    app.exec_()