[metapost] some question about pens

Dan Luecking luecking at uark.edu
Thu Apr 3 00:22:13 CEST 2008

At 02:02 PM 4/2/2008, Hartmut Henkel wrote:
>On Wed, 2 Apr 2008, Taco Hoekwater wrote:
> > Scratch the 'almost' here. It does exactly what I expected.
>metapost doesn't calculate the bounding box right in this case, see:

I recently noticed that metapost also doesn't get the correct
bounding box for mitered joins. I seems to always take
the bounding box of the path, extended by half the line
thickness (I'm using version 1.002). Of course, miters
can extend .5*(line thickness)*(miter limit) beyond the
path if the join corner is right on the edge.

>prologues := 3;
>path hc;
>   hc := halfcircle scaled 200;
>   linecap := squared;
>   draw hc shifted (150,300) withpen pencircle scaled 50;
>   draw bbox(currentpicture) withcolor red;
>   currentpicture := currentpicture shifted -llcorner(currentpicture);

This code:
   miterlimit := 11;
   linejoin := mitered;
   draw (0,0)--(72,7)--(0,14) withpen pencircle scaled 2bp;
gives bounding box (-1,-1) to (73,15). That causes both
epstopdf and mptopdf to clip the point off.


Daniel H. Luecking
Department of Mathematical Sciences
University of Arkansas
"Dubito ergo cogito, cogito ergo sum" --Descarte

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