Why does this example from the MetaFun manual not work?

Why does this example from the MetaFun manual not work?

[Gerben Wierda]

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I would like to use the result of transparent() straight in my macros, so I can pass the colors with transparency using a single parameter. That should be possible if I understand the MetaFun manual (where I’ve copy-pasted this example from):

\starttext
\startMPpage[instance=doublefun]

vardef SampleText (expr t, c) =
  save p ; picture p ;
  p := image (draw t infont "\truefontname{Regular}") ;
  draw (p shifted (- xpart center p,0)) scaled 5 withcolor c;
enddef ;
SampleText ("Much Of This"   , transparent(1, .5, red  )) ;
SampleText ("Functionality"  , transparent(1, .5, green)) ;
SampleText ("Was Written"    , transparent(1, .5, blue )) ;
SampleText ("While Listening", transparent(1, .5, cmyk(1,0,0,0))) ;
SampleText ("To the CD's Of" , transparent(1, .5, cmyk(0,1,0,0))) ;
SampleText ("Tori Amos"      , transparent(1, .5, cmyk(0,0,1,0))) ;

\stopMPpage
\stoptext

But it results in:

system          > files > jobname 'testcolor', input './testcolor', result 'testcolor'
fonts           > latin modern fonts are not preloaded
languages       > language 'en' is active
open source     > level 2, order 3, name './testcolor.tex'
fonts           > preloading latin modern fonts (second stage)
fonts           > 'fallback modern-designsize rm 12pt' is loaded
metapost        > initializing instance 'doublefun:1' using format 'metafun' and method 'double'
metapost        > loading 'metafun' as '/usr/local/context-osx-64/tex/texmf-context/metapost/context/base/mpiv/metafun.mpxl' using method 'double'
metapost        > initializing number mode 'double'
metapost log    > 
metapost log    > loading metafun, including plain.mp version 1.004 for metafun iv and xl
metapost log    > 
metapost log    > ! Missing ')' has been inserted.
metapost log    > <to be read again> 
metapost log    >                    withprescript
metapost log    > transparent->(1)withprescript
metapost log    >                              "tr_alternative="&decimal.transparency_alternat...
metapost log    > <*> ... ("Much Of This" , transparent(1, .5, red )
metapost log    >                                                   ) ; SampleText ("Functiona...
metapost log    > 
backend         > xmp > using file '/usr/local/context-osx-64/tex/texmf-context/tex/context/base/mkiv/lpdf-pdx.xml'
pages           > flushing realpage 1, userpage 1, subpage 1
close source    > level 2, order 3, name './testcolor.tex'
close source    > level 1, order 3, name 'cont-yes.mkiv'

For me, it is not about passing colour on to ConTeXt to typeset text, these are colors that normally would be drawn with “withcolor ca withtransparency (method,factor)” but that requires the passing of many more parameters and a lot more work in coding.

Does transparent() maybe produce a string that looks like “ca withtransparency (method,factor)” so something only usable in draw/fill/etc statements? But in that case how does that work without scantokens to parse the string?

Is there a way I can do this without having twice the parameters (and I have to pass multiple colours)  in my macros everywhere?

Thanks,

G

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Re: Why does this example from the MetaFun manual not work?

[Gerben Wierda]

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Nobody?

> On 8 Apr 2020, at 12:20, Gerben Wierda <gerben.wierda@rna.nl> wrote:
> 
> I would like to use the result of transparent() straight in my macros, so I can pass the colors with transparency using a single parameter. That should be possible if I understand the MetaFun manual (where I’ve copy-pasted this example from):
> 
> \starttext
> \startMPpage[instance=doublefun]
> 
> vardef SampleText (expr t, c) =
>   save p ; picture p ;
>   p := image (draw t infont "\truefontname{Regular}") ;
>   draw (p shifted (- xpart center p,0)) scaled 5 withcolor c;
> enddef ;
> SampleText ("Much Of This"   , transparent(1, .5, red  )) ;
> SampleText ("Functionality"  , transparent(1, .5, green)) ;
> SampleText ("Was Written"    , transparent(1, .5, blue )) ;
> SampleText ("While Listening", transparent(1, .5, cmyk(1,0,0,0))) ;
> SampleText ("To the CD's Of" , transparent(1, .5, cmyk(0,1,0,0))) ;
> SampleText ("Tori Amos"      , transparent(1, .5, cmyk(0,0,1,0))) ;
> 
> \stopMPpage
> \stoptext
> 
> But it results in:
> 
> system          > files > jobname 'testcolor', input './testcolor', result 'testcolor'
> fonts           > latin modern fonts are not preloaded
> languages       > language 'en' is active
> open source     > level 2, order 3, name './testcolor.tex'
> fonts           > preloading latin modern fonts (second stage)
> fonts           > 'fallback modern-designsize rm 12pt' is loaded
> metapost        > initializing instance 'doublefun:1' using format 'metafun' and method 'double'
> metapost        > loading 'metafun' as '/usr/local/context-osx-64/tex/texmf-context/metapost/context/base/mpiv/metafun.mpxl' using method 'double'
> metapost        > initializing number mode 'double'
> metapost log    > 
> metapost log    > loading metafun, including plain.mp version 1.004 for metafun iv and xl
> metapost log    > 
> metapost log    > ! Missing ')' has been inserted.
> metapost log    > <to be read again> 
> metapost log    >                    withprescript
> metapost log    > transparent->(1)withprescript
> metapost log    >                              "tr_alternative="&decimal.transparency_alternat...
> metapost log    > <*> ... ("Much Of This" , transparent(1, .5, red )
> metapost log    >                                                   ) ; SampleText ("Functiona...
> metapost log    > 
> backend         > xmp > using file '/usr/local/context-osx-64/tex/texmf-context/tex/context/base/mkiv/lpdf-pdx.xml'
> pages           > flushing realpage 1, userpage 1, subpage 1
> close source    > level 2, order 3, name './testcolor.tex'
> close source    > level 1, order 3, name 'cont-yes.mkiv'
> 
> For me, it is not about passing colour on to ConTeXt to typeset text, these are colors that normally would be drawn with “withcolor ca withtransparency (method,factor)” but that requires the passing of many more parameters and a lot more work in coding.
> 
> Does transparent() maybe produce a string that looks like “ca withtransparency (method,factor)” so something only usable in draw/fill/etc statements? But in that case how does that work without scantokens to parse the string?
> 
> Is there a way I can do this without having twice the parameters (and I have to pass multiple colours)  in my macros everywhere?
> 
> Thanks,
> 
> G
> ___________________________________________________________________________________
> 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
> ___________________________________________________________________________________


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___________________________________________________________________________________
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___________________________________________________________________________________

Re: Why does this example from the MetaFun manual not work?

[Taco Hoekwater]

Hi Gerben,

Changing the macro header to this will work:

   vardef SampleText (expr t)(text c) =

or you can use the answer from stackexchange, same approach.

BTW Hans would like people to use “withtransparency” instead as that is a 
newer, more flexible approach (but that would also need the above change,
or a split into multiple parameters).

Taco


> On 9 Apr 2020, at 09:04, Gerben Wierda <Gerben.Wierda@rna.nl> wrote:
> 
> Nobody?
> 
>> On 8 Apr 2020, at 12:20, Gerben Wierda <gerben.wierda@rna.nl> wrote:
>> 
>> I would like to use the result of transparent() straight in my macros, so I can pass the colors with transparency using a single parameter. That should be possible if I understand the MetaFun manual (where I’ve copy-pasted this example from):
>> 
>> \starttext
>> \startMPpage[instance=doublefun]
>> 
>> vardef SampleText (expr t, c) =
>>   save p ; picture p ;
>>   p := image (draw t infont "\truefontname{Regular}") ;
>>   draw (p shifted (- xpart center p,0)) scaled 5 withcolor c;
>> enddef ;
>> SampleText ("Much Of This"   , transparent(1, .5, red  )) ;
>> SampleText ("Functionality"  , transparent(1, .5, green)) ;
>> SampleText ("Was Written"    , transparent(1, .5, blue )) ;
>> SampleText ("While Listening", transparent(1, .5, cmyk(1,0,0,0))) ;
>> SampleText ("To the CD's Of" , transparent(1, .5, cmyk(0,1,0,0))) ;
>> SampleText ("Tori Amos"      , transparent(1, .5, cmyk(0,0,1,0))) ;
>> 
>> \stopMPpage
>> \stoptext
>> 
>> But it results in:
>> 
>> system          > files > jobname 'testcolor', input './testcolor', result 'testcolor'
>> fonts           > latin modern fonts are not preloaded
>> languages       > language 'en' is active
>> open source     > level 2, order 3, name './testcolor.tex'
>> fonts           > preloading latin modern fonts (second stage)
>> fonts           > 'fallback modern-designsize rm 12pt' is loaded
>> metapost        > initializing instance 'doublefun:1' using format 'metafun' and method 'double'
>> metapost        > loading 'metafun' as '/usr/local/context-osx-64/tex/texmf-context/metapost/context/base/mpiv/metafun.mpxl' using method 'double'
>> metapost        > initializing number mode 'double'
>> metapost log    > 
>> metapost log    > loading metafun, including plain.mp version 1.004 for metafun iv and xl
>> metapost log    > 
>> metapost log    > ! Missing ')' has been inserted.
>> metapost log    > <to be read again> 
>> metapost log    >                    withprescript
>> metapost log    > transparent->(1)withprescript
>> metapost log    >                              "tr_alternative="&decimal.transparency_alternat...
>> metapost log    > <*> ... ("Much Of This" , transparent(1, .5, red )
>> metapost log    >                                                   ) ; SampleText ("Functiona...
>> metapost log    > 
>> backend         > xmp > using file '/usr/local/context-osx-64/tex/texmf-context/tex/context/base/mkiv/lpdf-pdx.xml'
>> pages           > flushing realpage 1, userpage 1, subpage 1
>> close source    > level 2, order 3, name './testcolor.tex'
>> close source    > level 1, order 3, name 'cont-yes.mkiv'
>> 
>> For me, it is not about passing colour on to ConTeXt to typeset text, these are colors that normally would be drawn with “withcolor ca withtransparency (method,factor)” but that requires the passing of many more parameters and a lot more work in coding.
>> 
>> Does transparent() maybe produce a string that looks like “ca withtransparency (method,factor)” so something only usable in draw/fill/etc statements? But in that case how does that work without scantokens to parse the string?
>> 
>> Is there a way I can do this without having twice the parameters (and I have to pass multiple colours)  in my macros everywhere?
>> 
>> Thanks,
>> 
>> G
>> ___________________________________________________________________________________
>> 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
> ___________________________________________________________________________________

Taco Hoekwater
Elvenkind BV




___________________________________________________________________________________
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___________________________________________________________________________________

Re: Why does this example from the MetaFun manual not work?

[Gerben Wierda]

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Thank you.


> On 9 Apr 2020, at 10:01, Taco Hoekwater <taco@elvenkind.com> wrote:
> 
> Hi Gerben,
> 
> Changing the macro header to this will work:
> 
>   vardef SampleText (expr t)(text c) =
> 
> or you can use the answer from stackexchange, same approach.

> BTW Hans would like people to use “withtransparency” instead as that is a 
> newer, more flexible approach (but that would also need the above change,
> or a split into multiple parameters).

Oh, wait, I think I understand it. I would still do

vardef SampleText (expr t)(text c) =

and the call is SampleText( t, somecolor withtransparency sometransparency)

So, use withtrapsparency in the call?

I tried

\starttext
\startMPpage[instance=doublefun]

vardef SampleText (expr t)(text c)(text d) =
  save p ; picture p ;
  p := image (draw t infont "\truefontname{Regular}") ;
  draw (p shifted (- xpart center p,0)) scaled 5 withcolor c;
  draw (p shifted (- ypart center p,0)) scaled 5 withcolor d;
enddef;

SampleText ("Much Of This", transparent(1, .5, red  ) , transparent(1, .5, green  )) ;

\stopMPpage
\stoptext

But that does not work. Mmm. Maybe I need another approach to pass 4 values (r,g,b,t) as one parameter.

G 

> 
> Taco
> 
> 
>> On 9 Apr 2020, at 09:04, Gerben Wierda <Gerben.Wierda@rna.nl> wrote:
>> 
>> Nobody?
>> 
>>> On 8 Apr 2020, at 12:20, Gerben Wierda <gerben.wierda@rna.nl> wrote:
>>> 
>>> I would like to use the result of transparent() straight in my macros, so I can pass the colors with transparency using a single parameter. That should be possible if I understand the MetaFun manual (where I’ve copy-pasted this example from):
>>> 
>>> \starttext
>>> \startMPpage[instance=doublefun]
>>> 
>>> vardef SampleText (expr t, c) =
>>>  save p ; picture p ;
>>>  p := image (draw t infont "\truefontname{Regular}") ;
>>>  draw (p shifted (- xpart center p,0)) scaled 5 withcolor c;
>>> enddef ;
>>> SampleText ("Much Of This"   , transparent(1, .5, red  )) ;
>>> SampleText ("Functionality"  , transparent(1, .5, green)) ;
>>> SampleText ("Was Written"    , transparent(1, .5, blue )) ;
>>> SampleText ("While Listening", transparent(1, .5, cmyk(1,0,0,0))) ;
>>> SampleText ("To the CD's Of" , transparent(1, .5, cmyk(0,1,0,0))) ;
>>> SampleText ("Tori Amos"      , transparent(1, .5, cmyk(0,0,1,0))) ;
>>> 
>>> \stopMPpage
>>> \stoptext
>>> 
>>> But it results in:
>>> 
>>> system          > files > jobname 'testcolor', input './testcolor', result 'testcolor'
>>> fonts           > latin modern fonts are not preloaded
>>> languages       > language 'en' is active
>>> open source     > level 2, order 3, name './testcolor.tex'
>>> fonts           > preloading latin modern fonts (second stage)
>>> fonts           > 'fallback modern-designsize rm 12pt' is loaded
>>> metapost        > initializing instance 'doublefun:1' using format 'metafun' and method 'double'
>>> metapost        > loading 'metafun' as '/usr/local/context-osx-64/tex/texmf-context/metapost/context/base/mpiv/metafun.mpxl' using method 'double'
>>> metapost        > initializing number mode 'double'
>>> metapost log    > 
>>> metapost log    > loading metafun, including plain.mp version 1.004 for metafun iv and xl
>>> metapost log    > 
>>> metapost log    > ! Missing ')' has been inserted.
>>> metapost log    > <to be read again> 
>>> metapost log    >                    withprescript
>>> metapost log    > transparent->(1)withprescript
>>> metapost log    >                              "tr_alternative="&decimal.transparency_alternat...
>>> metapost log    > <*> ... ("Much Of This" , transparent(1, .5, red )
>>> metapost log    >                                                   ) ; SampleText ("Functiona...
>>> metapost log    > 
>>> backend         > xmp > using file '/usr/local/context-osx-64/tex/texmf-context/tex/context/base/mkiv/lpdf-pdx.xml'
>>> pages           > flushing realpage 1, userpage 1, subpage 1
>>> close source    > level 2, order 3, name './testcolor.tex'
>>> close source    > level 1, order 3, name 'cont-yes.mkiv'
>>> 
>>> For me, it is not about passing colour on to ConTeXt to typeset text, these are colors that normally would be drawn with “withcolor ca withtransparency (method,factor)” but that requires the passing of many more parameters and a lot more work in coding.
>>> 
>>> Does transparent() maybe produce a string that looks like “ca withtransparency (method,factor)” so something only usable in draw/fill/etc statements? But in that case how does that work without scantokens to parse the string?
>>> 
>>> Is there a way I can do this without having twice the parameters (and I have to pass multiple colours)  in my macros everywhere?
>>> 
>>> Thanks,
>>> 
>>> G
>>> ___________________________________________________________________________________
>>> 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
>> ___________________________________________________________________________________
> 
> Taco Hoekwater
> Elvenkind BV
> 
> 
> 
> 
> ___________________________________________________________________________________
> 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
> ___________________________________________________________________________________


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___________________________________________________________________________________

Re: Why does this example from the MetaFun manual not work?

[Taco Hoekwater]

Hi,

Using multiple (text <x>) arguments in macros doesn’t work, you would 
need to convert all but the last argument into (expr <x>) somehow.

That means that you probably cannot do a call like the one below at all.
(I, at least, do not see how you could convert one of those transparent 
colours into an expr <x> argument)

> 
> SampleText ("Much Of This", transparent(1, .5, red  ) , transparent(1, .5, green  )) ;

The situation may get even trickier because withtransparency() and
transparent() both use a  (text <x>) argument internally as well,
and I am not quite sure why.

At this point, I think you may need Hans for advice, sorry.

Taco

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___________________________________________________________________________________

Re: Why does this example from the MetaFun manual not work?

[Hans Hagen]

On 4/9/2020 11:01 AM, Taco Hoekwater wrote:
> Hi,
> 
> Using multiple (text <x>) arguments in macros doesn’t work, you would
> need to convert all but the last argument into (expr <x>) somehow.
> 
> That means that you probably cannot do a call like the one below at all.
> (I, at least, do not see how you could convert one of those transparent
> colours into an expr <x> argument)
> 
>>
>> SampleText ("Much Of This", transparent(1, .5, red  ) , transparent(1, .5, green  )) ;
> 
> The situation may get even trickier because withtransparency() and
> transparent() both use a  (text <x>) argument internally as well,
> and I am not quite sure why.
> 
> At this point, I think you may need Hans for advice, sorry.
Taco is right (of course). Indeed, one can end up in conflicts (mp has 
no transparency so it's all implemented using trickery). Anyway, using 
'infont' has no real benefits as it maps onto textext, so one can just 
use that one (also because it supports the anchoring suffixes which 
saves you the shift):

\starttext
\startMPpage[instance=doublefun]

draw textext("more recent"        ) withcolor red     withtransparency 
(1, .5) ;
draw textext("functionality"      ) withcolor green   withtransparency 
(1, .5) ;
draw textext("was written"        ) withcolor blue    withtransparency 
(1, .5) ;
draw textext("while listening"    ) withcolor magenta withtransparency 
(1, .5) ;
draw textext("to superb covers by") withcolor cyan    withtransparency 
(1, .5) ;
draw textext("Alyona Yarushina"   ) withcolor yellow  withtransparency 
(1, .5) ;

\stopMPpage
\stoptext

If something like "withcolor ... " is passed to a macro it has to be a 
text argument, not an expression (the transparent macro actually passed 
some abstraction); also, when making vardef's one need to omit the final 
semi colon in order to apply more properties to the 'return value'.

At some point I will update the metafun manual which means: remove old 
methods and exclusively use the new ones (currently the manual also 
discusses mpii while in context mkiv/lmtx we use mpiv macros).

For instance, when using colors one can best use named colors as these 
are consistent with the tex end, so often

   withcolor "red"

is better than

   withcolor red

etc etc etc etc

Hans


-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
        tel: 038 477 53 69 | www.pragma-ade.nl | 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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___________________________________________________________________________________

Re: Why does this example from the MetaFun manual not work?

[Henri Menke]

It would be really great if you'd stop wasting people's time by not
crossposting.

Cheers, Henri

On 09/04/20, 09:04, Gerben Wierda wrote:
> Nobody?
> 
> > On 8 Apr 2020, at 12:20, Gerben Wierda <gerben.wierda@rna.nl> wrote:
> > 
> > I would like to use the result of transparent() straight in my macros, so I can pass the colors with transparency using a single parameter. That should be possible if I understand the MetaFun manual (where I’ve copy-pasted this example from):
> > 
> > \starttext
> > \startMPpage[instance=doublefun]
> > 
> > vardef SampleText (expr t, c) =
> >   save p ; picture p ;
> >   p := image (draw t infont "\truefontname{Regular}") ;
> >   draw (p shifted (- xpart center p,0)) scaled 5 withcolor c;
> > enddef ;
> > SampleText ("Much Of This"   , transparent(1, .5, red  )) ;
> > SampleText ("Functionality"  , transparent(1, .5, green)) ;
> > SampleText ("Was Written"    , transparent(1, .5, blue )) ;
> > SampleText ("While Listening", transparent(1, .5, cmyk(1,0,0,0))) ;
> > SampleText ("To the CD's Of" , transparent(1, .5, cmyk(0,1,0,0))) ;
> > SampleText ("Tori Amos"      , transparent(1, .5, cmyk(0,0,1,0))) ;
> > 
> > \stopMPpage
> > \stoptext
> > 
> > But it results in:
> > 
> > system          > files > jobname 'testcolor', input './testcolor', result 'testcolor'
> > fonts           > latin modern fonts are not preloaded
> > languages       > language 'en' is active
> > open source     > level 2, order 3, name './testcolor.tex'
> > fonts           > preloading latin modern fonts (second stage)
> > fonts           > 'fallback modern-designsize rm 12pt' is loaded
> > metapost        > initializing instance 'doublefun:1' using format 'metafun' and method 'double'
> > metapost        > loading 'metafun' as '/usr/local/context-osx-64/tex/texmf-context/metapost/context/base/mpiv/metafun.mpxl' using method 'double'
> > metapost        > initializing number mode 'double'
> > metapost log    > 
> > metapost log    > loading metafun, including plain.mp version 1.004 for metafun iv and xl
> > metapost log    > 
> > metapost log    > ! Missing ')' has been inserted.
> > metapost log    > <to be read again> 
> > metapost log    >                    withprescript
> > metapost log    > transparent->(1)withprescript
> > metapost log    >                              "tr_alternative="&decimal.transparency_alternat...
> > metapost log    > <*> ... ("Much Of This" , transparent(1, .5, red )
> > metapost log    >                                                   ) ; SampleText ("Functiona...
> > metapost log    > 
> > backend         > xmp > using file '/usr/local/context-osx-64/tex/texmf-context/tex/context/base/mkiv/lpdf-pdx.xml'
> > pages           > flushing realpage 1, userpage 1, subpage 1
> > close source    > level 2, order 3, name './testcolor.tex'
> > close source    > level 1, order 3, name 'cont-yes.mkiv'
> > 
> > For me, it is not about passing colour on to ConTeXt to typeset text, these are colors that normally would be drawn with “withcolor ca withtransparency (method,factor)” but that requires the passing of many more parameters and a lot more work in coding.
> > 
> > Does transparent() maybe produce a string that looks like “ca withtransparency (method,factor)” so something only usable in draw/fill/etc statements? But in that case how does that work without scantokens to parse the string?
> > 
> > Is there a way I can do this without having twice the parameters (and I have to pass multiple colours)  in my macros everywhere?
> > 
> > Thanks,
> > 
> > G
> > ___________________________________________________________________________________
> > 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
___________________________________________________________________________________