passvariable(); path problem

passvariable(); path problem

[Peter Rolf]

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Hi,

I played around with the new passvariable() option and ran into errors
when passing a path. Used the latest beta (01.10.2013). Can someone
confirm this?

Peter

[-- Attachment #2: minimal.mkiv --]
[-- Type: text/plain, Size: 101 bytes --]

\starttext
\startMPcode
    passvariable("path",fullcircle scaled 1cm) ;
\stopMPcode
\stoptext 

[-- Attachment #3: Type: text/plain, Size: 485 bytes --]

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Re: passvariable(); path problem

[Hans Hagen]

On 10/4/2013 2:52 PM, Peter Rolf wrote:
> Hi,
>
> I played around with the new passvariable() option and ran into errors
> when passing a path. Used the latest beta (01.10.2013). Can someone
> confirm this?

in mp-mlib.mpiv:

vardef mfun_path_to_string(expr p) =
     mfun_point_to_string(p,1) for i=2 upto length(p) : & " " & 
mfun_point_to_string(p,i) endfor
enddef ;

vardef mfun_boolean_to_string(expr b) =
     if b : "true" else : "false" fi
enddef ;

(i forgot to rename the argument when outlining the code)

fwiw: in your case you still get an (empty) graphic, use 
\startMPcalculation ... when you don't want that

Hans

-----------------------------------------------------------------
                                           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
-----------------------------------------------------------------
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___________________________________________________________________________________

Re: passvariable(); path problem

[Peter Rolf]

Am 04.10.2013 16:15, schrieb Hans Hagen:
> On 10/4/2013 2:52 PM, Peter Rolf wrote:
>> Hi,
>>
>> I played around with the new passvariable() option and ran into errors
>> when passing a path. Used the latest beta (01.10.2013). Can someone
>> confirm this?
> 
> in mp-mlib.mpiv:
> 
> vardef mfun_path_to_string(expr p) =
>     mfun_point_to_string(p,1) for i=2 upto length(p) : & " " &
> mfun_point_to_string(p,i) endfor
> enddef ;
> 
> vardef mfun_boolean_to_string(expr b) =
>     if b : "true" else : "false" fi
> enddef ;
> 
> (i forgot to rename the argument when outlining the code)
> 
> fwiw: in your case you still get an (empty) graphic, use
> \startMPcalculation ... when you don't want that
>

Many thanks! Good to know, but in this case I just need the path.


> Hans
> 
> -----------------------------------------------------------------
>                                           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
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> archive  : http://foundry.supelec.fr/projects/contextrev/
> wiki     : http://contextgarden.net
> ___________________________________________________________________________________
> 
> 

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___________________________________________________________________________________

Re: passvariable(); path problem

[Peter Rolf]

Am 04.10.2013 16:47, schrieb Peter Rolf:
> Am 04.10.2013 16:15, schrieb Hans Hagen:
>> On 10/4/2013 2:52 PM, Peter Rolf wrote:
>>> Hi,
>>>
>>> I played around with the new passvariable() option and ran into errors
>>> when passing a path. Used the latest beta (01.10.2013). Can someone
>>> confirm this?
>>
>> in mp-mlib.mpiv:
>>
>> vardef mfun_path_to_string(expr p) =
>>     mfun_point_to_string(p,1) for i=2 upto length(p) : & " " &
>> mfun_point_to_string(p,i) endfor
>> enddef ;
>>
>> vardef mfun_boolean_to_string(expr b) =
>>     if b : "true" else : "false" fi
>> enddef ;
>>
>> (i forgot to rename the argument when outlining the code)
>>
>> fwiw: in your case you still get an (empty) graphic, use
>> \startMPcalculation ... when you don't want that
>>
> 
> Many thanks! Good to know, but in this case I just need the path.

:-D

now I know what you mean...

> 
> 
>> Hans
>>
>> -----------------------------------------------------------------
>>                                           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
>> ___________________________________________________________________________________
>>
>>
> 
> ___________________________________________________________________________________
> 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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> ___________________________________________________________________________________
> 

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___________________________________________________________________________________

Re: passvariable(); path problem

[Peter Rolf]

I played around with it, but I have problems to understand the format of
the returned path.

Example:
% --------
\setuppagenumber[state=stop]

\starttext
\nopdfcompression

\startMPpage
  path p;
  p:= (20,20){up} .. {down}(200,100);
  passvariable("path",p);
  draw p ;
\stopMPpage

\ctxlua{inspect{metapost.variables["path"]}}
\stoptext
% -------

The PDF code of the path is (mainly)

20.000000 20.000000 m
20.000000 190.342880 200.000000 184.016693 200.000000 100.000000 c

"path" contains

table={
 {
  { 200, 100, 200, 184.0167, 200, 100 },
 },
}

The end point and the second control point are the same, as in the PDF
code. But how do I calculate the starting point and the first control
point from the returned values?
And is the type of operation (line, curve,..) given by the number of values?


Peter

Am 04.10.2013 16:15, schrieb Hans Hagen:
> On 10/4/2013 2:52 PM, Peter Rolf wrote:
>> Hi,
>>
>> I played around with the new passvariable() option and ran into errors
>> when passing a path. Used the latest beta (01.10.2013). Can someone
>> confirm this?
> 
> in mp-mlib.mpiv:
> 
> vardef mfun_path_to_string(expr p) =
>     mfun_point_to_string(p,1) for i=2 upto length(p) : & " " &
> mfun_point_to_string(p,i) endfor
> enddef ;
> 
> vardef mfun_boolean_to_string(expr b) =
>     if b : "true" else : "false" fi
> enddef ;
> 
> (i forgot to rename the argument when outlining the code)
> 
> fwiw: in your case you still get an (empty) graphic, use
> \startMPcalculation ... when you don't want that
> 
> Hans
> 
> -----------------------------------------------------------------
>                                           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
> ___________________________________________________________________________________
> 
> 

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___________________________________________________________________________________

Re: passvariable(); path problem

[Hans Hagen]

On 10/5/2013 5:52 PM, Peter Rolf wrote:
> I played around with it, but I have problems to understand the format of
> the returned path.
>
> Example:
> % --------
> \setuppagenumber[state=stop]
>
> \starttext
> \nopdfcompression
>
> \startMPpage
>    path p;
>    p:= (20,20){up} .. {down}(200,100);
>    passvariable("path",p);
>    draw p ;
> \stopMPpage
>
> \ctxlua{inspect{metapost.variables["path"]}}
> \stoptext
> % -------
>
> The PDF code of the path is (mainly)
>
> 20.000000 20.000000 m
> 20.000000 190.342880 200.000000 184.016693 200.000000 100.000000 c
>
> "path" contains
>
> table={
>   {
>    { 200, 100, 200, 184.0167, 200, 100 },
>   },
> }
>
> The end point and the second control point are the same, as in the PDF
> code. But how do I calculate the starting point and the first control
> point from the returned values?

something

local prev = nil
for i=1,#path do
     local current = path[i]
     if not prev then
         print(current[1],current[2],"m")
     else
         print(prev[5],prev[6],prev[3],prev[4],current[1],current[2],"c")
     end
     prev = current
end
-- close last to first if needed

 > And is the type of operation (line, curve,..) given by the number of 
values?

by analyzing using thresholds (one can just use "c" always, as "l" is an 
optimization)

Hans

-----------------------------------------------------------------
                                           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
-----------------------------------------------------------------
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___________________________________________________________________________________

Re: passvariable(); path problem

[Peter Rolf]

Am 06.10.2013 00:37, schrieb Hans Hagen:
> On 10/5/2013 5:52 PM, Peter Rolf wrote:
>> I played around with it, but I have problems to understand the format of
>> the returned path.
>>
>> Example:
>> % --------
>> \setuppagenumber[state=stop]
>>
>> \starttext
>> \nopdfcompression
>>
>> \startMPpage
>>    path p;
>>    p:= (20,20){up} .. {down}(200,100);
>>    passvariable("path",p);
>>    draw p ;
>> \stopMPpage
>>
>> \ctxlua{inspect{metapost.variables["path"]}}
>> \stoptext
>> % -------
>>
>> The PDF code of the path is (mainly)
>>
>> 20.000000 20.000000 m
>> 20.000000 190.342880 200.000000 184.016693 200.000000 100.000000 c
>>
>> "path" contains
>>
>> table={
>>   {
>>    { 200, 100, 200, 184.0167, 200, 100 },
>>   },
>> }
>>
>> The end point and the second control point are the same, as in the PDF
>> code. But how do I calculate the starting point and the first control
>> point from the returned values?
> 
> something
> 
> local prev = nil
> for i=1,#path do
>     local current = path[i]
>     if not prev then
>         print(current[1],current[2],"m")
>     else
>         print(prev[5],prev[6],prev[3],prev[4],current[1],current[2],"c")
>     end
>     prev = current
> end
> -- close last to first if needed
> 
>> And is the type of operation (line, curve,..) given by the number of
> values?
> 
> by analyzing using thresholds (one can just use "c" always, as "l" is an
> optimization)
> 
> Hans
> 

Thanks for the explanation. I think I have understood the scheme (but I
might be wrong, because this doesn't help me with my example).

Where is the starting point['20 20'] in the returned example path? Same
is true for the first control point ['20 190.34']. Either I'm missing
something, or the returned path data is incomplete.


Peter

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Re: passvariable(); path problem

[Hans Hagen]

On 10/6/2013 3:05 PM, Peter Rolf wrote:

> Thanks for the explanation. I think I have understood the scheme (but I
> might be wrong, because this doesn't help me with my example).
>
> Where is the starting point['20 20'] in the returned example path? Same
> is true for the first control point ['20 190.34']. Either I'm missing
> something, or the returned path data is incomplete.

you get just the value of the path variable in your mp code, not a ps or 
whatever representation and in mp a path has just points so the starting 
point is the x y of the first point

-----------------------------------------------------------------
                                           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
-----------------------------------------------------------------
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___________________________________________________________________________________

Re: passvariable(); path problem

[Peter Rolf]

Am 06.10.2013 17:06, schrieb Hans Hagen:
> On 10/6/2013 3:05 PM, Peter Rolf wrote:
> 
>> Thanks for the explanation. I think I have understood the scheme (but I
>> might be wrong, because this doesn't help me with my example).
>>
>> Where is the starting point['20 20'] in the returned example path? Same
>> is true for the first control point ['20 190.34']. Either I'm missing
>> something, or the returned path data is incomplete.
> 
> you get just the value of the path variable in your mp code, not a ps or
> whatever representation and in mp a path has just points so the starting
> point is the x y of the first point
>

I tested several examples and the only time that the starting point was
part of the returned path was, when the path only consists of one point.
In all other cases it was missing.

This is a bit contrary to my definition of a (complete) path. Anyhow,
thanks for the pointer :-)

Peter

> -----------------------------------------------------------------
>                                           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
> ___________________________________________________________________________________
> 
> 

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___________________________________________________________________________________

Re: passvariable(); path problem

[luigi scarso]

[-- Attachment #1.1: Type: text/plain, Size: 1642 bytes --]

On Mon, Oct 7, 2013 at 10:48 AM, Peter Rolf <indiego@gmx.net> wrote:

> Am 06.10.2013 17:06, schrieb Hans Hagen:
> > On 10/6/2013 3:05 PM, Peter Rolf wrote:
> >
> >> Thanks for the explanation. I think I have understood the scheme (but I
> >> might be wrong, because this doesn't help me with my example).
> >>
> >> Where is the starting point['20 20'] in the returned example path? Same
> >> is true for the first control point ['20 190.34']. Either I'm missing
> >> something, or the returned path data is incomplete.
> >
> > you get just the value of the path variable in your mp code, not a ps or
> > whatever representation and in mp a path has just points so the starting
> > point is the x y of the first point
> >
>
> I tested several examples and the only time that the starting point was
> part of the returned path was, when the path only consists of one point.
> In all other cases it was missing.
>
> This is a bit contrary to my definition of a (complete) path. Anyhow,
> thanks for the pointer :-)
>
>
in mp-mlib.mpiv should be :
vardef mfun_path_to_string(expr p) =
    mfun_point_to_string(p,0) for i=1 upto length(p) : & " " &
mfun_point_to_string(p,i) endfor
enddef ;


(You can fix it and rebuild the format. To understand the output, is better
to know that mfun_point_to_string is

 vardef mfun_point_to_string(expr p,i) =
    decimal xpart (point       i of p) & " " &
    decimal ypart (point       i of p) & " " &
    decimal xpart (precontrol  i of p) & " " &
    decimal ypart (precontrol  i of p) & " " &
    decimal xpart (postcontrol i of p) & " " &
    decimal ypart (postcontrol i of p)
enddef ;

)


-- 
luigi

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___________________________________________________________________________________

Re: passvariable(); path problem

[Hans Hagen]

On 10/7/2013 11:47 AM, luigi scarso wrote:

> (You can fix it and rebuild the format. To understand the output, is
> better to know that mfun_point_to_string is

no need to rebuild the format (at least not currently) as mp loads runtime

the next beta will have (the somewhat useless) helper:

\starttext

\startluacode

     local result = metapost.quickanddirty("metafun",[[ draw fullcircle 
scaled 1cm ;]])

     context("% t",result.bbox)
     context.par()
     context("% t",result.code)
     context.par()

\stopluacode

\stoptext

-----------------------------------------------------------------
                                           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
-----------------------------------------------------------------
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___________________________________________________________________________________

Re: passvariable(); path problem

[Peter Rolf]

Am 07.10.2013 11:47, schrieb luigi scarso:
> 
> 
> 
> On Mon, Oct 7, 2013 at 10:48 AM, Peter Rolf <indiego@gmx.net
> <mailto:indiego@gmx.net>> wrote:
> 
>     Am 06.10.2013 17:06, schrieb Hans Hagen:
>     > On 10/6/2013 3:05 PM, Peter Rolf wrote:
>     >
>     >> Thanks for the explanation. I think I have understood the scheme
>     (but I
>     >> might be wrong, because this doesn't help me with my example).
>     >>
>     >> Where is the starting point['20 20'] in the returned example
>     path? Same
>     >> is true for the first control point ['20 190.34']. Either I'm missing
>     >> something, or the returned path data is incomplete.
>     >
>     > you get just the value of the path variable in your mp code, not a
>     ps or
>     > whatever representation and in mp a path has just points so the
>     starting
>     > point is the x y of the first point
>     >
> 
>     I tested several examples and the only time that the starting point was
>     part of the returned path was, when the path only consists of one point.
>     In all other cases it was missing.
> 
>     This is a bit contrary to my definition of a (complete) path. Anyhow,
>     thanks for the pointer :-)
> 
> 
> in mp-mlib.mpiv should be :
> vardef mfun_path_to_string(expr p) =
>     mfun_point_to_string(p,0) for i=1 upto length(p) : & " " &
> mfun_point_to_string(p,i) endfor
> enddef ;
> 
> 
> (You can fix it and rebuild the format. To understand the output, is
> better to know that mfun_point_to_string is
> 
>  vardef mfun_point_to_string(expr p,i) =
>     decimal xpart (point       i of p) & " " &
>     decimal ypart (point       i of p) & " " &
>     decimal xpart (precontrol  i of p) & " " &
>     decimal ypart (precontrol  i of p) & " " &
>     decimal xpart (postcontrol i of p) & " " &
>     decimal ypart (postcontrol i of p)
> enddef ;
> 
> )
> 
> 
> -- 
> luigi

@Luigi: thanks for the fix!

@Hans: quickanddirty sounds promising (bbox is needed anyway) :-D

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