#!/usr/bin/env python

import sys
from PyQt4.QtCore import Qt
from PyQt4.QtGui import *

class MDIArea(QMdiArea):

    def __init__(self, background_pixmap, parent = None):
    
        QMdiArea.__init__(self, parent)
        self.background_pixmap = background_pixmap
        self.centered = False
    
    def paintEvent(self, event):
    
        painter = QPainter()
        painter.begin(self.viewport())
        
        if not self.centered:
            painter.drawPixmap(0, 0, self.width(), self.height(), self.background_pixmap)
        else:
            painter.fillRect(event.rect(), self.palette().color(QPalette.Window))
            x = (self.width() - self.display_pixmap.width())/2
            y = (self.height() - self.display_pixmap.height())/2
            painter.drawPixmap(x, y, self.display_pixmap)
        
        painter.end()
    
    def resizeEvent(self, event):
    
        self.display_pixmap = self.background_pixmap.scaled(event.size(), Qt.KeepAspectRatio)


if __name__ == "__main__":

    app = QApplication(sys.argv)
    
    if len(app.arguments()) != 2:
    
        sys.stderr.write("Usage: %s <image path>\n" % sys.argv[0])
        sys.exit(1)
    
    m = MDIArea(QPixmap(sys.argv[1]))
    m.centered = True
    m.show()
    sys.exit(app.exec_())