gistfile1.py

#!/usr/bin/env python

from PyQt4 import QtCore, QtGui

class GraphWidget(QtGui.QGraphicsView):
    def __init__(self):
        super(GraphWidget, self).__init__()
        
        self.font = QtGui.QFont("System")
        fontinfo = self.finfo = QtGui.QFontMetrics(self.font)
        self.lsize = fontinfo.size(0, "A")
        self.wsize = QtCore.QSize(self.lsize.width() * 80, self.lsize.height() * 25)
        
        scene = QtGui.QGraphicsScene(self)
        scene.setItemIndexMethod(QtGui.QGraphicsScene.NoIndex)
        scene.setSceneRect(-200, -200, self.wsize.width(), self.wsize.height())

        self.setScene(scene)
        self.setCacheMode(QtGui.QGraphicsView.CacheBackground)
        self.setViewportUpdateMode(QtGui.QGraphicsView.BoundingRectViewportUpdate)
        self.setRenderHint(QtGui.QPainter.Antialiasing)

        self.setMinimumSize(self.wsize.width(), self.wsize.height())
        self.setWindowTitle("Testing")

    def drawBackground(self, painter, rect):
        sceneRect = self.sceneRect()
        painter.setFont(self.font)
        painter.setPen(QtCore.Qt.black)
        message = "A"*80
        painter.drawText(sceneRect, (message + "\n")*25)
        for x in xrange(3):
            self.drawCharAt(painter, "Z", x, 1)
        
    def drawCharAt(self, painter, char, x = 1, y = 1):
        x = self.lsize.width() * x
        y = self.lsize.height() * y
        painter.setFont(self.font)
        painter.setPen(QtCore.Qt.green)
        painter.drawRect(x, y-self.lsize.height(), self.lsize.width(), self.lsize.height())
        painter.setPen(QtCore.Qt.black)
        painter.drawText(x, y, char)

if __name__ == '__main__':

    import sys

    app = QtGui.QApplication(sys.argv)

    widget = GraphWidget()
    widget.show()
    sys.exit(app.exec_())