From: Hans Hagen <j.hagen@xs4all.nl>
To: mailing list for ConTeXt users <ntg-context@ntg.nl>,
mf <massifr@fastwebnet.it>
Subject: Re: metapost: remapping colors of an SVG picture
Date: Tue, 18 Feb 2020 14:53:06 +0100 [thread overview]
Message-ID: <a39100d4-b2eb-81b4-404c-1e03d5b7e3f4@xs4all.nl> (raw)
In-Reply-To: <851949ba-cc76-e672-56d6-0a19c4085f22@fastwebnet.it>
On 2/18/2020 12:18 PM, mf wrote:
> Hello list,
> I tried this:
>
> \starttext
> \startMPcode
> picture p ; p := lmt_svg [ filename = "sample.svg" ] ;
> draw p ;
> color black_rgb ; black_rgb := ( 0, 0, 0 ) ;
> color red_rgb ; red_rgb := ( 1, 0, 0 ) ;
> remapcolor( black_rgb, red_rgb ) ;
> recolor p ;
> draw p shifted ( bbwidth(p) + 5mm, 0) ;
> \stopMPcode
> \stoptext
\setupcolors[rgb=no]
\startMPcode
draw lmt_svg [ filename = "sample.svg" ] ;
\stopMPcode
> but recolor gives an error:
> metapost log > >> picture
> metapost log > ! Wrong picture color model: redpart of grey object.
> metapost log > <for(picture)> _f_:=(redpart(EXPR0),
> metapost log > greenpart(EXPR0),bluepart(EXPR0));if.bou...
> metapost log >
> metapost log > repathed->...fi;fi;else:addto._p_.also.i;fi;endfor
> metapost log > ;setbounds._p_.to._b_;_p_....
> metapost log > <to be read again>
> metapost log > ;
> metapost log > <*> ...apcolor( black_rgb, red_rgb ) ; recolor p ;
> metapost log > draw grayed p shifted ( b...
> metapost log >
>
> My goal is to remap colors of an SVG image, like this:
>
> \starttext
> \startMPcode
> picture p ; p := lmt_svg [ filename = "sample.svg" ] ;
> draw p ;
> color black_rgb ; black_rgb := ( 0, 0, 0 ) ;
> cmykcolor black_cmyk ; black_cmyk := ( 0, 0, 0, 1 ) ;
> remapcolor( black_rgb, black_cmyk ) ;
> recolor p ;
> draw p shifted ( bbwidth(p) + 5mm, 0) ;
> \stopMPcode
> \stoptext
>
> It relates to a recent thread in the mailing list about color management.
> It's an attempt to use inkscape-made SVG graphics inside a CMYK
> workflow, without using color management.
>
> Naturally it would work under some constraints, but there's a lot of
> graphics you can do with Inkscape that falls inside these:
> - the number of colors in the input SVG should be limited, so that every
> color gets converted
> - no embedded bitmaps, only vector graphics
> - perhaps some other constraints on gradients, transparency, etc.
>
> A good alternative would be a remapper based on a custom lua function
> like this:
>
> function rgb2cmyk( r, g, b )
> ...
> return c, m, y, k
> end
>
> Massi
>
> ___________________________________________________________________________________
> 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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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
webpage : http://www.pragma-ade.nl / http://context.aanhet.net
archive : https://bitbucket.org/phg/context-mirror/commits/
wiki : http://contextgarden.net
___________________________________________________________________________________
next prev parent reply other threads:[~2020-02-18 13:53 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-18 11:18 mf
2020-02-18 13:53 ` Hans Hagen [this message]
2020-02-18 18:07 ` Jan U. Hasecke
2020-02-18 18:17 ` mf
2020-02-18 18:24 ` Jan U. Hasecke
2020-02-20 9:29 ` Jan U. Hasecke
2020-02-20 17:30 ` Hans Hagen
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