[metapost] How to use a thinner pen?

[Rodolfo Medina]

Rodolfo Medina wrote:

>> It seems that I don't manage to use a pen thinner than the default 0.5bp.
>> When I give the command: `pickup pencircle scaled 0.1bp', or even `pickup
>> pencircle scaled 0.0000001bp', my eye can't notice any difference with the
>> default thickness.  Instead, a bigger thickness works fine.  What am I
>> missing?



"Troy Henderson" <thenders at gmail.com> writes:

> It's very likely your viewer.  That is, GV (and others) eventually
> rasterize images as a last step to displaying them on the screen.  As
> such, they probably have a minimum stroke width that is allowed and
> anything smaller than that gets rounded up to this minimum amount.
> I'm seeing something like this in Acroread.  As I zoom in, the size of
> the stroke doesn't change but of course the rest of the graphic does
> (magnifies).  So, the relative sizes is changed meaning that the small
> stroke is more accurate when magnified.



If I convert the ps file into pdf format with ps2pdf, then if I magnify the
picture by the 400% I can view the thinner line, and also I can view it if I
print the picture on a paper.  This seems to confirm that the problem is due
to gv.  Within gv, when I try to magnify the picture beyond a certain level, I
get error messages.

Rodolfo