Bug plotting very small values

Hi,

Plotting some very small values (~1E-306) will break mpl with the error:

   File "/usr/lib/python2.5/site-packages/matplotlib/backends/backend_agg.py", line 154, in draw_text
     self._renderer.draw_text_image(font.get_image(), int(x), int(y) + 1, angle, gc)
OverflowError: cannot convert float infinity to long

Very large values don't seem to be a problem and this bug seems to be backend independent. Also, for some reason the minimum double value representable in C and Python seem to be different... On my machine (i686 GNU/Linux, 32 bits Debian testing) the C DBL_MIN is ~1E-308, but Python seem to 1E-323 or so (Python 2.5.5). I'm using the latest mpl svn (rev 8414).

Regards,
Jo�o Silva

Example script -----------------------------------------------------

import numpy as np
import matplotlib.pyplot as plt
n = 10
x = np.linspace(0.0,10.0,n)
plt.plot(x,1E-306*np.ones(n))
plt.show()

···

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