How to get randomly coloured text in metapost?

How to get randomly coloured text in metapost?

[Marco]

Hi,

how to get random colours for text inside textext? Take a look at the
following example (MKIV).

\definecolor [static] [r=.9, g=.7, b=.8]
\starttext
\startuseMPgraphic {1}

def col=
  (uniformdeviate(1),uniformdeviate(1),uniformdeviate(1))
enddef;

% These dots have a random color
for i=0 upto 5:
  fill fullcircle scaled 5mm xshifted i*1cm withcolor col;
endfor;

% withcolor does not work, »Test« is black
for i=0 upto 5:
  label(textext("Test"), (i*1cm,-1cm))  withcolor col;
endfor;

% To get a static color I use the following construct
for i=0 upto 5:
  label(textext("\color[static]Test"), (i*1cm,-2cm));
endfor;

\stopuseMPgraphic
\useMPgraphic {1}
\stoptext

Is it possible to get the metapost construct »withcolor« to work with
text or do I have to take a different approach?

Thanks for any help.
Marco


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Re: How to get randomly coloured text in metapost?

[Alan BRASLAU]

On Tuesday 11 May 2010 17:48:09 Marco wrote:
> Hi,
> 
> how to get random colours for text inside textext? Take a look at the
> following example (MKIV).
> 
> \definecolor [static] [r=.9, g=.7, b=.8]
> \starttext
> \startuseMPgraphic {1}
> 
> def col=
>   (uniformdeviate(1),uniformdeviate(1),uniformdeviate(1))
> enddef;
> 
> % These dots have a random color
> for i=0 upto 5:
>   fill fullcircle scaled 5mm xshifted i*1cm withcolor col;
> endfor;
> 
> % withcolor does not work, »Test« is black
> for i=0 upto 5:
>   label(textext("Test"), (i*1cm,-1cm))  withcolor col;
> endfor;
> 
> % To get a static color I use the following construct
> for i=0 upto 5:
>   label(textext("\color[static]Test"), (i*1cm,-2cm));
> endfor;
> 
> \stopuseMPgraphic
> \useMPgraphic {1}
> \stoptext
> 
> Is it possible to get the metapost construct »withcolor« to work with
> text or do I have to take a different approach?
> 
> Thanks for any help.
> Marco

I understood from a much earlier discussion with Hans that "withcolor"
will not be made to work with text, whose color therefore has to be
set with ConTeXt constructs.

Alan
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___________________________________________________________________________________

Re: How to get randomly coloured text in metapost?

[Marco]

> > Is it possible to get the metapost construct »withcolor« to work
> > with text or do I have to take a different approach?
>
> I understood from a much earlier discussion with Hans that "withcolor"
> will not be made to work with text, whose color therefore has to be
> set with ConTeXt constructs.
Thanks for the information. But how to do this? How can I set up the
randomness in ConTeXt? I browsed a bit through the sources and found a
lua snipped producing random integers. So here's my first attempt.

% only Integers, so not much variation in color :-(
\def\r{\ctxlua{commands.getrandomcounta(0,1)}}

% Defining the colour at this point makes it kind of static again
\definecolor[my][r=\r,g=\r,b=\r]
\starttext
\startuseMPgraphic {1}

% The colour is all the same, but different in each run
for i=0 upto 5:
  label(textext("\color[my]{Test}"), (i*1cm,-2cm));
endfor;

% Does not work, results in compile error
% for i=0 upto 5:
%   label(textext("\definecolor[my][r=\r,g=\r,b=\r]\color[my]{Test}"),
%       (i*1cm,-3cm));
% endfor;

\stopuseMPgraphic
\useMPgraphic {1}
\stoptext

Maybe this code is an improvable step in the right direction, maybe it's
rubbish. Necessary improvements need to be:

    i) need of floating point random numbers
   ii) random colours per call and not per ConTeXt run
  iii) the use is quite verbose, so need to put it in a macro

Any hints appreciated.

Marco


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Re: How to get randomly coloured text in metapost?

[Hans Hagen]

On 11-5-2010 7:38, Marco wrote:
> label(textext("\definecolor[my][r=\r,g=\r,b=\r]\color[my]{Test}"),
> %       (i*1cm,-3cm));

numeric r, g, b ;

r := uniformdeviate 1 ;
g := uniformdeviate 1 ;
b := uniformdeviate 1 ;

textext("\colored[r=" & r & ",g=" & g & ",b=" & b & "]{Test}")

etc

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___________________________________________________________________________________

Re: How to get randomly coloured text in metapost?

[Marco]

> numeric r, g, b ;
> 
> r := uniformdeviate 1 ;
> g := uniformdeviate 1 ;
> b := uniformdeviate 1 ;
> 
> textext("\colored[r=" & r & ",g=" & g & ",b=" & b & "]{Test}")
Thanks for this snipped, Hans. It looks promising, but I get the
following compile error:

    !mplib          : mp terminal: >> "\colored [r="
    >> 0.74464
    ! Not implemented: (string)&(known numeric).
    <to be read again> 

I used the following code:

\starttext
\startuseMPgraphic {1}

numeric r, g, b ;
r := uniformdeviate 1 ;
g := uniformdeviate 1 ;
b := uniformdeviate 1 ;

label(textext("\colored[r=" & r & ",g=" & g & ",b=" & b & "]{Test}"),
origin);

\stopuseMPgraphic
\useMPgraphic {1}
\stoptext

Marco


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Re: How to get randomly coloured text in metapost?

[Mojca Miklavec]

On Tue, May 11, 2010 at 21:03, Marco wrote:
>> numeric r, g, b ;
>>
>> r := uniformdeviate 1 ;
>> g := uniformdeviate 1 ;
>> b := uniformdeviate 1 ;
>>
>> textext("\colored[r=" & r & ",g=" & g & ",b=" & b & "]{Test}")
> Thanks for this snipped, Hans. It looks promising, but I get the
> following compile error:
>
>    !mplib          : mp terminal: >> "\colored [r="
>    >> 0.74464
>    ! Not implemented: (string)&(known numeric).
>    <to be read again>

You need to convert number to string first. Use "decimal(r)" instead
of "r". (But I didn't test.)

Mojca
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Re: How to get randomly coloured text in metapost?

[Marco]

> You need to convert number to string first. Use "decimal(r)" instead
> of "r". (But I didn't test.)
> 
> Mojca
Thanks, Mojca. Works like a charm now.

Marco


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Re: How to get randomly coloured text in metapost?

[luigi scarso]

On Tue, May 11, 2010 at 9:27 PM, Mojca Miklavec
<mojca.miklavec.lists@gmail.com> wrote:
> On Tue, May 11, 2010 at 21:03, Marco wrote:
>>> numeric r, g, b ;
>>>
>>> r := uniformdeviate 1 ;
>>> g := uniformdeviate 1 ;
>>> b := uniformdeviate 1 ;
>>>
>>> textext("\colored[r=" & r & ",g=" & g & ",b=" & b & "]{Test}")
>> Thanks for this snipped, Hans. It looks promising, but I get the
>> following compile error:
>>
>>    !mplib          : mp terminal: >> "\colored [r="
>>    >> 0.74464
>>    ! Not implemented: (string)&(known numeric).
>>    <to be read again>
>
> You need to convert number to string first. Use "decimal(r)" instead
> of "r". (But I didn't test.)
>
> Mojca
> ___________________________________________________________________________________
> 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
> ___________________________________________________________________________________
>

\starttext
\startuseMPgraphic {1}

numeric r, g, b ;
r := uniformdeviate 1 ;
g := uniformdeviate 1 ;
b := uniformdeviate 1 ;

label(textext("\colored[r=" & decimal(r) & ",g=" & decimal(g) & ",b="
& decimal(b) & "]{Test}"),origin);
label(textext("r=" & decimal(r) & ",g=" & decimal(g) & ",b=" &
decimal(b) ),origin+(0,-100));

\stopuseMPgraphic
\useMPgraphic {1}
\stoptext

( tested :-)  )

Warning: default is preserve seed (every runs will have the same random number)
if you don't purge temporary files *tuo, *tui etc.
I'm sure that there is a switch/macros to avoid this, but I don't
remember it  now

-- 
luigi
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