[metapost] envelope

[Nicola]

On 2016-09-16 07:06:19 +0000, Hans Hagen said:

> On 9/15/2016 8:27 PM, Daniel H. Luecking wrote:
>> Nicola:
>> 
>> The syntax is
>> envelope <polygonal pen> of <path primary>
>> 
>> For example,
>> path p;
>> p := envelope pensquare of (up--left);
>> 
>> It returns the path which, when filled, produces the effect of stroking
>> the pen along the path. Elliptical pens (e.g., pencircle) produce an error.
>> 
>> Stroking an elliptical pen is simply passed on to PostScript. But polygonal
>> pens (inherited from metafont) require this as a workaround.
>> 
>> I deduced this by a little trial and error based on some descriptions in
>> the web source mp.w.
> 
> Here's what happens in the result.
> 
> [snip]

Thanks for the illuminating examples!
Nicola