[metapost] Mptopdf crops its output

[Franck Pastor]

Hello,

I am using MetaPost version 0.993 (TeXLive 2007) on MacOSX Tiger. I  
usually convert my MetaPost files with mptopdf (version 1.3.2),  
before transmitting them my to colleagues. But the pdf pictures  
produces by mptopdf are often cropped, part of the drawing are cut in  
the edges of the frame.  To give an example, if I create this simple  
program, which produces an ovegrown "eight":

beginfig(0);
	label(btex 8 etex, (0, 0)) scaled 20 pt;
endfig;
end;

save it under the name "example.mp", enter "mpost example" and then  
"mptopdf example.0", and view the resulting pdf file or print it, the  
numeral 8 is  cropped at its top and its bottom.

Is it the same on other configurations ? And what could I do to avoid  
it ?

Note that I can't apply mptopdf directly to the file "example.mp",  
since it doesn't work at all, but it's another problem.

Thanks,

Franck Pastor