Dear Mikael,
> Le 20 déc. 2021 à 12:14, Mikael Sundqvist <mic...@gmail.com> a écrit :
>
> Hi,
>
> I will try again. What if you do
>
> newcircleA := newcircleA scrutinized 2;
>
> after your definition of newcircleA?
Once I understood I had to compile with LMTX, this works like magic ! I spent
hours to find a solution… but here is a solution !
Thanks a lot !
>
> /Mikael
Fabrice.
>
>
> On Mon, Dec 20, 2021 at 3:45 PM Fabrice L <fabrice.al...@gmail.com> wrote:
>>
>> Thanks Mikael,
>>
>> Le 20 déc. 2021 à 02:21, Mikael Sundqvist via ntg-context
>> <ntg-context@ntg.nl> a écrit :
>>
>> Hi,
>>
>> would it be an option for you to do
>>
>> newcircleA := circleA cutbefore P1 cutafter P2 -- cycle ;
>>
>> In that case you avoid extra points.
>>
>>
>> You are right, in this simple case, your solution avoid the problem, and is
>> applicable in some of my cases (I have to rethink the code). Thanks for the
>> proposition !
>> But in others cases this is not possible (I think). Imagine I wish to do a «
>> partial moon » from the two circles in my minimal example (see bottom right
>> of the attached pdf):
>>
>>
>> newcircleA := circleA cutbefore P1 cutafter P2 .. reverse(circleB cutbefore
>> P1 cutafter P2) .. cycle;
>>
>> I need 10 points to define the shape, but as my connections are duplicated,
>> I have 12 points.
>>
>> The solution (I thought) would be to use the « & » operator :
>> newcircleA := circleA cutbefore P1 cutafter P2 & reverse(circleB cutbefore
>> P1 cutafter P2) & cycle ;
>>
>> But this does not work (same reason as before: "! Paths don't touch; `&'
>> will be changed to `..'.").
>>
>> The compete minimal code (if somebody wants to plus with it) is here :
>>
>> % ———————————————————————
>> \startMPpage
>> path circleA , circleB ;
>> pair P[];
>> defaultscale := 0.4 ;
>>
>> circleA := fullcircle scaled 1in randomized 3 ;
>> circleB := fullcircle scaled 1in randomized 3 shifted(0.3in,0.3in) ;
>>
>> draw circleA withcolor blue ;
>> draw circleB withcolor red ;
>>
>> P[1] := circleA intersectionpoint circleB ;
>> dotlabel.lft("$P_1$",P[1]) ;
>> dotlabel.rt("$\blue\tfx P_0^A$",point 0 of circleA) ;
>> P[2] := reverse(circleA) intersectionpoint circleB ;
>> dotlabel.rt("$P_2$",P[2]) ;
>> dotlabel.rt("$\red\tfx P_0^B$",point 0 of circleB) ;
>>
>> path newcircleA , newcircleB ;
>> % newcircleA := (circleA cutbefore P1 cutafter P2 ) & (P2 -- P1) & cycle ;
>> % previous line gives an error :
>> % "! Paths don't touch; `&' will be changed to `..'."
>> newcircleA := circleA cutbefore P1 cutafter P2 -- (P2 -- P1) -- cycle ;
>> newcircleA := newcircleA xshifted 2in ;
>> draw newcircleA withcolor darkgreen ;
>>
>> newcircleB := (circleB cutafter P1) -- (P1 -- P2) -- (circleB cutbefore P2
>> ) & cycle ;
>> newcircleB := newcircleB xshifted 2in ;
>> draw newcircleB withcolor black ;
>> drawpoints newcircleA ; drawpointlabels newcircleA ;
>>
>> % Mikael solution
>> newcircleA := circleA cutbefore P1 cutafter P2 -- cycle ;
>> newcircleA := newcircleA yshifted -1.5in ;
>> draw newcircleA withcolor darkgreen ;
>> drawpoints newcircleA ; drawpointlabels newcircleA ;
>>
>> % partial moon
>> newcircleA := circleA cutbefore P1 cutafter P2
>> .. reverse(circleB cutbefore P1 cutafter P2) .. cycle;
>> % & (reverse(circleB) cutbefore P2 cutafter P1) & cycle;
>> newcircleA := newcircleA shifted(2in,-1.5in) ;
>> draw newcircleA withcolor magenta ;
>> drawpoints newcircleA ; drawpointlabels newcircleA ;
>>
>> \stopMPpage
>> % ———————————————————————
>>
>> Thanks for any help !
>> Fabrice.
>>
>>
>> /Mikael
>>
>> On Mon, Dec 20, 2021 at 5:30 AM Fabrice L via ntg-context
>> <ntg-context@ntg.nl> wrote:
>>
>>
>> Dear list,
>>
>> I have a problem connecting path with the operator « & » (page 16 Metafun
>> manual). The problem is illustrated by the code (and the joined PDF) which
>> follows.
>>
>> I draw random cycled forms (left part of the figure) and when they
>> interact, they are modified to « fit together » (right part of the figure) .
>> When building these new forms, I connect paths (usually two or three
>> depending on position 0 of the path); the last point a path is the same as
>> the first point of the next path ; for exemple, to modify the blue circle,
>> named « circleA », I take the circle A from P1 to P2, then a segment from P2
>> to P1 and cycle to have a closed path. So I should be able to do :
>>
>> newcircleA := circleA cutbefore P1 cutafter P2 & (P2 -- P1) & cycle ;
>>
>> The « & » operator is supposed to work (if I understand correctly) in this
>> case, but I have this error message :
>>
>> "! Paths don't touch; `&' will be changed to `..’."
>>
>> Which I do not understand since the paths « touch ». There was a similar
>> question last year, without a clear answer («
>> METAPOST subpath rounding issue
>> »https://www.mail-archive.com/ntg-context@ntg.nl/msg94294.html).
>>
>> A solution is to ignore the repeating points :
>> newcircleA := circleA cutbefore P1 cutafter P2 -- (P2 -- P1) -- cycle ;
>> but this new shape has 9 points instead of 7. The problem is that I do these
>> operations a number of times, and the length of a path (in the number of
>> points) is increasing and cause trouble when I look for intersections with
>> others shapes.
>>
>> Here is the MWE:
>>
>> \startMPpage
>> path circleA , circleB ;
>> pair P[];
>>
>> circleA := fullcircle scaled 1in randomized 3 ;
>> circleB := fullcircle scaled 1in randomized 3 shifted(0.3in,0.3in) ;
>>
>> draw circleA withcolor blue ;
>> draw circleB withcolor red ;
>>
>> P[1] := circleA intersectionpoint circleB ;
>> dotlabel.lft("$P_1$",P[1]) ;
>> dotlabel.rt("$\blue\tfx P_0^A$",point 0 of circleA) ;
>> P[2] := reverse(circleA) intersectionpoint circleB ;
>> dotlabel.rt("$P_2$",P[2]) ;
>> dotlabel.rt("$\red\tfx P_0^B$",point 0 of circleB) ;
>>
>> path newcircleA , newcircleB ;
>> % newcircleA := circleA cutbefore P1 cutafter P2 & (P2 -- P1) & cycle ;
>> % previous line gives an error :
>> % "! Paths don't touch; `&' will be changed to `..'."
>> newcircleA := circleA cutbefore P1 cutafter P2 -- (P2 -- P1) -- cycle ;
>> newcircleA := newcircleA xshifted 2in ;
>> draw newcircleA withcolor darkgreen ;
>>
>> newcircleB := (circleB cutafter P1) -- (P1 -- P2) -- (circleB cutbefore P2
>> ) & cycle ;
>> newcircleB := newcircleB xshifted 2in ;
>> draw newcircleB withcolor black ;
>> drawpoints newcircleA ; drawpointlabels newcircleA ;
>>
>> \stopMPpage
>>
>>
>>
>>
>> I would appreciate any help ! Thanks !
>> Fabrice.
>>
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