我是matplotlib的新用户，我的平台是Ubuntu 10.04 Python 2.6.5

这是我的代码

import matplotlib
matplotlib.use('Agg')
import matplotlib.pyplot as plt 
plt.plot([1,2,3])

错误是：

/usr/local/lib/python2.6/dist-packages/matplotlib/backends/__init__.py:41: UserWarning: 
Your currently selected backend, 'agg' does not support show().
Please select a GUI backend in your matplotlibrc file ('/usr/local/lib/python2.6/dist-packages/matplotlib/mpl-data/matplotlibrc')
or with matplotlib.use()
  (backend, matplotlib.matplotlib_fname()))

• 我安装了“防颗粒几何”库，apt-get install libagg但是它不起作用。
• 我尝试使用后端的其他参数，例如“ GTK”和“ TkAgg”。
• 我安装了python-gtk2-dev软件包，但错误仍在下面。
• 谁能告诉我一个可执行的后端参数及其依赖库？

这是错误：

>>> matplotlib.use('GTK')
>>> import matplotlib.pyplot as plt
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python2.6/dist-packages/matplotlib/pyplot.py", line 95, in <module>
    new_figure_manager, draw_if_interactive, show = pylab_setup()
  File "/usr/local/lib/python2.6/dist-packages/matplotlib/backends/__init__.py", line 25, in pylab_setup
    globals(),locals(),[backend_name])
  File "/usr/local/lib/python2.6/dist-packages/matplotlib/backends/backend_gtk.py", line 28, in <module>
    from matplotlib.backends.backend_gdk import RendererGDK, FigureCanvasGDK 
  File "/usr/local/lib/python2.6/dist-packages/matplotlib/backends/backend_gdk.py", line 29, in <module>
    from matplotlib.backends._backend_gdk import pixbuf_get_pixels_array
ImportError: No module named _backend_gdk