Strange behavior with Metapost

Strange behavior with Metapost

[Fabrice Couvreur]

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Hello,
Why curve drawn is not that expected ?
Fabrice

\starttext
\startMPcode
     input hvdm;
     l:=2.8mm; r:=0.6; alfa:=45; beta:=0; gamma:=0;
     defineDefaultArrow (l, r, alfa, beta, gamma);
     numeric xmin, xmax, ymin, ymax;
     xmin :=-2; xmax := 4; ymax :=5 ;ymin:=-1; u := 1cm;
     pickup pencircle scaled 1pt ;
     drawarrow ((xmin,0) -- (xmax,0)) scaled u;
     drawarrow ((0,ymin) -- (0,ymax)) scaled u;
     draw tightfunction ("x", "2*(x-1)*(x-1)+2", xmin, xmax,
(xmax-xmin)/10)
     scaled u;
     setbounds currentpicture to boundingbox (((xmin,ymin) --
     (xmax,ymax)) scaled u);
\stopMPcode
\stoptext

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Re: Strange behavior with Metapost

[Hans Hagen]

On 5/27/2014 10:19 PM, Fabrice Couvreur wrote:
> Hello,
> Why curve drawn is not that expected ?
> Fabrice

use  /20

> \starttext
> \startMPcode
>       input hvdm;
>       l:=2.8mm; r:=0.6; alfa:=45; beta:=0; gamma:=0;
>       defineDefaultArrow (l, r, alfa, beta, gamma);
>       numeric xmin, xmax, ymin, ymax;
>       xmin :=-2; xmax := 4; ymax :=5 ;ymin:=-1; u := 1cm;
>       pickup pencircle scaled 1pt ;
>       drawarrow ((xmin,0) -- (xmax,0)) scaled u;
>       drawarrow ((0,ymin) -- (0,ymax)) scaled u;
>       draw tightfunction ("x", "2*(x-1)*(x-1)+2", xmin, xmax,
> (xmax-xmin)/10)
>       scaled u;
>       setbounds currentpicture to boundingbox (((xmin,ymin) --
>       (xmax,ymax)) scaled u);
> \stopMPcode
> \stoptext
>
>
>
> ___________________________________________________________________________________
> 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://tex.aanhet.net
> archive  : http://foundry.supelec.fr/projects/contextrev/
> wiki     : http://contextgarden.net
> ___________________________________________________________________________________
>


-- 

-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
     tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com
                                              | www.pragma-pod.nl
-----------------------------------------------------------------
___________________________________________________________________________________
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://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________

Re: Strange behavior with Metapost

[Fabrice]

It works. But how to choose not to avoid this problem (/10 or /20 or ....) ?

Another little problem: if I use

" setbounds currentpicture to boundingbox (((xmin,ymin) --(xmax,ymax)) 
scaled u) ; "

the images are not adjusted to the BoundingBox.
So I'm back to my original idea.
Fabrice

> \midaligned{%
> \startcombination[4*1]
> {%
> \startMPcode
>      input hvdm;
>      l:=2.8mm; r:=0.6; alfa:=45; beta:=0; gamma:=0;
>      defineDefaultArrow (l, r, alfa, beta, gamma);
>      numeric xmin, xmax, ymin, ymax;
>      xmin := -2; xmax :=4; ymax :=5 ;ymin:=-1; u := 0.7cm;
>      pickup pencircle scaled 1pt ;
>      drawarrow ((xmin,0) -- (xmax,0)) scaled u;
>      drawarrow ((0,ymin) -- (0,ymax)) scaled u;
>      draw tightfunction ("x", "-2*(x-1)*(x-1)+2", xmin, xmax, 
> (xmax-xmin)/20)
>      scaled u;
>      path screen;
> screen=(xmin,ymin)*u--(xmax,ymin)*u--(xmax,ymax)*u--(xmin,ymax)*u--cycle;
>      clip currentpicture to screen;
> \stopMPcode
> }{1.}
> {%
> \startMPcode
>      input hvdm;
>      l:=2.8mm; r:=0.6; alfa:=45; beta:=0; gamma:=0;
>      defineDefaultArrow (l, r, alfa, beta, gamma);
>      numeric xmin, xmax, ymin, ymax;
>      xmin := -2; xmax :=4; ymax :=5 ;ymin:=-1; u := 0.7cm;
>      pickup pencircle scaled 1pt ;
>      drawarrow ((xmin,0) -- (xmax,0)) scaled u;
>      drawarrow ((0,ymin) -- (0,ymax)) scaled u;
>      draw tightfunction ("x", "0.5*(x-1)*(x-1)+2", xmin, xmax, 
> (xmax-xmin)/20)
>      scaled u;
>      path screen;
> screen=(xmin,ymin)*u--(xmax,ymin)*u--(xmax,ymax)*u--(xmin,ymax)*u--cycle;
>      clip currentpicture to screen;
> \stopMPcode
> }
> {2.}
> {%
> \startMPcode
>      input hvdm;
>      l:=2.8mm; r:=0.6; alfa:=45; beta:=0; gamma:=0;
>      defineDefaultArrow (l, r, alfa, beta, gamma);
>      numeric xmin, xmax, ymin, ymax;
>      xmin := -2; xmax :=4; ymax :=5 ;ymin:=-1; u := 0.7cm;
>      pickup pencircle scaled 1pt ;
>      drawarrow ((xmin,0) -- (xmax,0)) scaled u;
>      drawarrow ((0,ymin) -- (0,ymax)) scaled u;
>      draw tightfunction ("x", "-0.5*(x-1)*(x-1)+2", xmin, xmax, 
> (xmax-xmin)/20)
>      scaled u;
>      path screen;
> screen=(xmin,ymin)*u--(xmax,ymin)*u--(xmax,ymax)*u--(xmin,ymax)*u--cycle;
>      clip currentpicture to screen;
> \stopMPcode
> }
> {3.}
> {%
> \startMPcode
>      input hvdm;
>      l:=2.8mm; r:=0.6; alfa:=45; beta:=0; gamma:=0;
>      defineDefaultArrow (l, r, alfa, beta, gamma);
>      numeric xmin, xmax, ymin, ymax;
>      xmin := -2; xmax :=4; ymax :=5 ;ymin:=-1; u := 0.7cm;
>      pickup pencircle scaled 1pt ;
>      drawarrow ((xmin,0) -- (xmax,0)) scaled u;
>      drawarrow ((0,ymin) -- (0,ymax)) scaled u;
>      draw tightfunction ("x", "2*(x-1)*(x-1)+2", xmin, xmax, 
> (xmax-xmin)/20)
>      scaled u;
>      path screen;
> screen=(xmin,ymin)*u--(xmax,ymin)*u--(xmax,ymax)*u--(xmin,ymax)*u--cycle;
>      clip currentpicture to screen;
> \stopMPcode}
> {4.}
> \stopcombination}

___________________________________________________________________________________
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://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________

Re: Strange behavior with Metapost

[Hans Hagen]

On 5/28/2014 12:09 AM, Fabrice wrote:
> It works. But how to choose not to avoid this problem (/10 or /20 or
> ....) ?

well, you can guess the amount of steps ... but the 1000 you had 
originally was way too much



-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
     tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com
                                              | www.pragma-pod.nl
-----------------------------------------------------------------
___________________________________________________________________________________
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://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________

Re: Strange behavior with Metapost

[Fabrice]

Hello,
Firstly, thank you for your reply. However, I would like some further 
explanation please.
If I understand, but I'm not sure at all, calculating (xmax-xmin) / 10 
gives the number of points to draw the curve. However, in my example, 
xmax = 4 and xmin = -2, so (xmax-xmin) / 10 = 0.6. My question is : how 
do you find the value in 1000 ?
___________________________________________________________________________________
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://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________