* Metafun: how to draw a straight line past the end points
@ 2020-12-09 15:57 Otared Kavian
2020-12-09 16:19 ` Fabrice L
0 siblings, 1 reply; 8+ messages in thread
From: Otared Kavian @ 2020-12-09 15:57 UTC (permalink / raw)
To: mailing list for ConTeXt users
Hi,
I have a silly question: given two points in the plane
z1 = (1cm,3cm) ;
z2 = (5cm, 9cm) ;
the command
draw z1 -- z2 withpen pencircle scaled .5pt ;
draws the line segment joining z1 and z2. How could I draw the line segment which goes a little further (say 1cm) than both the end points of this segment (that is in this example, a point before z1 and a point after z2 on the straight line) .
Indeed it is possible to write the equation of the line and then compute by hand the coordinates of the new end points, but I think there is a simpler way in Metafun to do this.
Thanks for any help: Otared
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* Re: Metafun: how to draw a straight line past the end points
2020-12-09 15:57 Metafun: how to draw a straight line past the end points Otared Kavian
@ 2020-12-09 16:19 ` Fabrice L
2020-12-09 17:11 ` Otared Kavian
0 siblings, 1 reply; 8+ messages in thread
From: Fabrice L @ 2020-12-09 16:19 UTC (permalink / raw)
To: mailing list for ConTeXt users
Hi,
> Le 9 déc. 2020 à 10:57, Otared Kavian <otared@gmail.com> a écrit :
>
> Hi,
>
> I have a silly question: given two points in the plane
> z1 = (1cm,3cm) ;
> z2 = (5cm, 9cm) ;
> the command
> draw z1 -- z2 withpen pencircle scaled .5pt ;
> draws the line segment joining z1 and z2. How could I draw the line segment which goes a little further (say 1cm) than both the end points of this segment (that is in this example, a point before z1 and a point after z2 on the straight line) .
> Indeed it is possible to write the equation of the line and then compute by hand the coordinates of the new end points, but I think there is a simpler way in Metafun to do this.
The shortened operation is the solution ! See MetaFun manual section 1.18
\starttext
\startMPpage
z1 = (1cm,3cm) ;
z2 = (5cm, 9cm) ;
draw (z1--z2) shortened -1cm withcolor blue ;
draw (z1--z2) withcolor red ;
\stopMPpage
\stoptext
Fabrice.
>
> Thanks for any help: Otared
>
>
> ___________________________________________________________________________________
> If your question is of interest to others as well, please add an entry to the Wiki!
>
> maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
> webpage : http://www.pragma-ade.nl / http://context.aanhet.net
> archive : https://bitbucket.org/phg/context-mirror/commits/
> wiki : http://contextgarden.net
> ___________________________________________________________________________________
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!
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* Re: Metafun: how to draw a straight line past the end points
2020-12-09 16:19 ` Fabrice L
@ 2020-12-09 17:11 ` Otared Kavian
2020-12-09 17:37 ` Aditya Mahajan
0 siblings, 1 reply; 8+ messages in thread
From: Otared Kavian @ 2020-12-09 17:11 UTC (permalink / raw)
To: mailing list for ConTeXt users
Hi Fabrice,
Thanks a lot ! Indeed that does the job, which shows how wonderful Metafun is !
Best regards: Otared
> On 9 Dec 2020, at 17:19, Fabrice L <fabrice.alpha@gmail.com> wrote:
>
> Hi,
>
>> Le 9 déc. 2020 à 10:57, Otared Kavian <otared@gmail.com> a écrit :
>>
>> Hi,
>>
>> I have a silly question: given two points in the plane
>> z1 = (1cm,3cm) ;
>> z2 = (5cm, 9cm) ;
>> the command
>> draw z1 -- z2 withpen pencircle scaled .5pt ;
>> draws the line segment joining z1 and z2. How could I draw the line segment which goes a little further (say 1cm) than both the end points of this segment (that is in this example, a point before z1 and a point after z2 on the straight line) .
>> Indeed it is possible to write the equation of the line and then compute by hand the coordinates of the new end points, but I think there is a simpler way in Metafun to do this.
>
> The shortened operation is the solution ! See MetaFun manual section 1.18
>
> \starttext
> \startMPpage
> z1 = (1cm,3cm) ;
> z2 = (5cm, 9cm) ;
> draw (z1--z2) shortened -1cm withcolor blue ;
> draw (z1--z2) withcolor red ;
>
> \stopMPpage
> \stoptext
>
> Fabrice.
>
>>
>> Thanks for any help: Otared
>>
>>
>> ___________________________________________________________________________________
>> If your question is of interest to others as well, please add an entry to the Wiki!
>>
>> maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
>> webpage : http://www.pragma-ade.nl / http://context.aanhet.net
>> archive : https://bitbucket.org/phg/context-mirror/commits/
>> wiki : http://contextgarden.net
>> ___________________________________________________________________________________
>
> ___________________________________________________________________________________
> If your question is of interest to others as well, please add an entry to the Wiki!
>
> maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
> webpage : http://www.pragma-ade.nl / http://context.aanhet.net
> archive : https://bitbucket.org/phg/context-mirror/commits/
> wiki : http://contextgarden.net
> ___________________________________________________________________________________
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!
maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage : http://www.pragma-ade.nl / http://context.aanhet.net
archive : https://bitbucket.org/phg/context-mirror/commits/
wiki : http://contextgarden.net
___________________________________________________________________________________
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: Metafun: how to draw a straight line past the end points
2020-12-09 17:11 ` Otared Kavian
@ 2020-12-09 17:37 ` Aditya Mahajan
2020-12-09 19:34 ` Otared Kavian
0 siblings, 1 reply; 8+ messages in thread
From: Aditya Mahajan @ 2020-12-09 17:37 UTC (permalink / raw)
To: mailing list for ConTeXt users
On Wed, 9 Dec 2020, Otared Kavian wrote:
> Thanks a lot ! Indeed that does the job, which shows how wonderful Metafun is !
Or, if you want to use high school algebra:
\starttext
\startMPcode
z1 = (1cm,3cm) ;
z2 = (5cm, 9cm) ;
z3 = 1cm * dir(angle (z2 - z1)) shifted z2;
draw z1 -- z3 ;
draw z1 -- z2 withcolor red;
\stopMPcode
\stoptext
Aditya
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___________________________________________________________________________________
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* Re: Metafun: how to draw a straight line past the end points
2020-12-09 17:37 ` Aditya Mahajan
@ 2020-12-09 19:34 ` Otared Kavian
2020-12-09 20:38 ` Aditya Mahajan
0 siblings, 1 reply; 8+ messages in thread
From: Otared Kavian @ 2020-12-09 19:34 UTC (permalink / raw)
To: mailing list for ConTeXt users
Hi Aditya,
Thanks for the alternative method, which comes handy if one wishes to extend the straight line by a different amount at either end:
\starttext
\startMPcode
z1 = (1cm,3cm) ;
z2 = (5cm, 9cm) ;
z3 = 1cm * dir(angle (z2 - z1)) shifted z2 ;
z4 = -.5cm*dir(angle(z2 - z1)) shifted z1 ;
draw z1 -- z3 ;
draw z4 -- z1 ;
draw z1 -- z2 withcolor red ;
\stopMPcode
\stoptext
Best regards: Otared
> On 9 Dec 2020, at 18:37, Aditya Mahajan <adityam@umich.edu> wrote:
>
> On Wed, 9 Dec 2020, Otared Kavian wrote:
>
>> Thanks a lot ! Indeed that does the job, which shows how wonderful Metafun is !
>
> Or, if you want to use high school algebra:
>
> \starttext
> \startMPcode
> z1 = (1cm,3cm) ;
> z2 = (5cm, 9cm) ;
> z3 = 1cm * dir(angle (z2 - z1)) shifted z2;
> draw z1 -- z3 ;
> draw z1 -- z2 withcolor red;
> \stopMPcode
> \stoptext
>
> Aditya
> ___________________________________________________________________________________
> If your question is of interest to others as well, please add an entry to the Wiki!
>
> maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
> webpage : http://www.pragma-ade.nl / http://context.aanhet.net
> archive : https://bitbucket.org/phg/context-mirror/commits/
> wiki : http://contextgarden.net
> ___________________________________________________________________________________
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!
maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage : http://www.pragma-ade.nl / http://context.aanhet.net
archive : https://bitbucket.org/phg/context-mirror/commits/
wiki : http://contextgarden.net
___________________________________________________________________________________
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: Metafun: how to draw a straight line past the end points
2020-12-09 19:34 ` Otared Kavian
@ 2020-12-09 20:38 ` Aditya Mahajan
2020-12-09 21:19 ` Otared Kavian
2020-12-09 22:01 ` Hans Hagen
0 siblings, 2 replies; 8+ messages in thread
From: Aditya Mahajan @ 2020-12-09 20:38 UTC (permalink / raw)
To: mailing list for ConTeXt users
On Wed, 9 Dec 2020, Otared Kavian wrote:
> Hi Aditya,
>
> Thanks for the alternative method, which comes handy if one wishes to extend the straight line by a different amount at either end:
>
> \starttext
> \startMPcode
> z1 = (1cm,3cm) ;
> z2 = (5cm, 9cm) ;
> z3 = 1cm * dir(angle (z2 - z1)) shifted z2 ;
> z4 = -.5cm*dir(angle(z2 - z1)) shifted z1 ;
> draw z1 -- z3 ;
> draw z4 -- z1 ;
> draw z1 -- z2 withcolor red ;
> \stopMPcode
> \stoptext
Or just redefine shortened to accept a pair!
\startMPdefinitions
primarydef p shortened d =
reverse ( ( reverse (p enlonged -xpart paired(d)) ) enlonged -ypart paired(d) )
enddef ;
\stopMPdefinitions
\starttext
\startMPpage
z1 = (1cm,3cm) ;
z2 = (5cm, 9cm) ;
draw (z1--z2) shortened (-1cm,-2cm) withcolor blue ;
draw (z1--z2) withcolor red ;
\stopMPpage
\stoptext
Now that if you really want to shorten a path, then cutends works better than shortened
\startMPdefinitions
primarydef p shortened d =
reverse ( ( reverse (p enlonged -xpart paired(d)) ) enlonged -ypart paired(d) )
enddef ;
\stopMPdefinitions
\starttext
\startMPpage
z1 = (1cm,3cm) ;
z2 = (5cm, 9cm) ;
path p, q;
p := z1 {up} .. {right} z2;
q := p shifted (6cm, 0);
draw p withcolor red ;
draw p shortened (1cm,2cm) withcolor blue ;
draw q withcolor green ;
draw q cutends (1cm,2cm) withcolor blue ;
\stopMPpage
\stoptext
Aditya
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If your question is of interest to others as well, please add an entry to the Wiki!
maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
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___________________________________________________________________________________
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: Metafun: how to draw a straight line past the end points
2020-12-09 20:38 ` Aditya Mahajan
@ 2020-12-09 21:19 ` Otared Kavian
2020-12-09 22:01 ` Hans Hagen
1 sibling, 0 replies; 8+ messages in thread
From: Otared Kavian @ 2020-12-09 21:19 UTC (permalink / raw)
To: mailing list for ConTeXt users
Thanks Aditya!
One can learn a lot with your answers !
In the Metafun manual I see enlonged but I did not know to use it.
Best regards: Otared
> On 9 Dec 2020, at 21:38, Aditya Mahajan <adityam@umich.edu> wrote:
>
> On Wed, 9 Dec 2020, Otared Kavian wrote:
>
>> Hi Aditya,
>>
>> Thanks for the alternative method, which comes handy if one wishes to extend the straight line by a different amount at either end:
>>
>> \starttext
>> \startMPcode
>> z1 = (1cm,3cm) ;
>> z2 = (5cm, 9cm) ;
>> z3 = 1cm * dir(angle (z2 - z1)) shifted z2 ;
>> z4 = -.5cm*dir(angle(z2 - z1)) shifted z1 ;
>> draw z1 -- z3 ;
>> draw z4 -- z1 ;
>> draw z1 -- z2 withcolor red ;
>> \stopMPcode
>> \stoptext
>
> Or just redefine shortened to accept a pair!
>
> \startMPdefinitions
> primarydef p shortened d =
> reverse ( ( reverse (p enlonged -xpart paired(d)) ) enlonged -ypart paired(d) )
> enddef ;
> \stopMPdefinitions
>
>
>
> \starttext
> \startMPpage
> z1 = (1cm,3cm) ;
> z2 = (5cm, 9cm) ;
> draw (z1--z2) shortened (-1cm,-2cm) withcolor blue ;
> draw (z1--z2) withcolor red ;
>
> \stopMPpage
> \stoptext
>
> Now that if you really want to shorten a path, then cutends works better than shortened
>
> \startMPdefinitions
> primarydef p shortened d =
> reverse ( ( reverse (p enlonged -xpart paired(d)) ) enlonged -ypart paired(d) )
> enddef ;
> \stopMPdefinitions
>
>
> \starttext
> \startMPpage
> z1 = (1cm,3cm) ;
> z2 = (5cm, 9cm) ;
> path p, q;
> p := z1 {up} .. {right} z2;
> q := p shifted (6cm, 0);
>
> draw p withcolor red ;
> draw p shortened (1cm,2cm) withcolor blue ;
>
> draw q withcolor green ;
> draw q cutends (1cm,2cm) withcolor blue ;
>
> \stopMPpage
> \stoptext
>
> Aditya
> ___________________________________________________________________________________
> If your question is of interest to others as well, please add an entry to the Wiki!
>
> maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
> webpage : http://www.pragma-ade.nl / http://context.aanhet.net
> archive : https://bitbucket.org/phg/context-mirror/commits/
> wiki : http://contextgarden.net
> ___________________________________________________________________________________
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!
maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage : http://www.pragma-ade.nl / http://context.aanhet.net
archive : https://bitbucket.org/phg/context-mirror/commits/
wiki : http://contextgarden.net
___________________________________________________________________________________
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: Metafun: how to draw a straight line past the end points
2020-12-09 20:38 ` Aditya Mahajan
2020-12-09 21:19 ` Otared Kavian
@ 2020-12-09 22:01 ` Hans Hagen
1 sibling, 0 replies; 8+ messages in thread
From: Hans Hagen @ 2020-12-09 22:01 UTC (permalink / raw)
To: mailing list for ConTeXt users, Aditya Mahajan
On 12/9/2020 9:38 PM, Aditya Mahajan wrote:
> Or just redefine shortened to accept a pair!
>
> \startMPdefinitions
> primarydef p shortened d =
> reverse ( ( reverse (p enlonged -xpart paired(d)) ) enlonged -ypart paired(d) )
> enddef ;
> \stopMPdefinitions
patched but then also:
primarydef p enlonged len =
begingroup
if len == 0 :
p
elseif pair p :
...
in order to save some energy when one is zero
Hans
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maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
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___________________________________________________________________________________
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2020-12-09 15:57 Metafun: how to draw a straight line past the end points Otared Kavian
2020-12-09 16:19 ` Fabrice L
2020-12-09 17:11 ` Otared Kavian
2020-12-09 17:37 ` Aditya Mahajan
2020-12-09 19:34 ` Otared Kavian
2020-12-09 20:38 ` Aditya Mahajan
2020-12-09 21:19 ` Otared Kavian
2020-12-09 22:01 ` Hans Hagen
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