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From: Hans Hagen via ntg-context <ntg-context@ntg.nl>
To: "Jairo A. del Rio via ntg-context" <ntg-context@ntg.nl>
Cc: Hans Hagen <j.hagen@xs4all.nl>
Subject: Re: Passing colors to Metafun and TeX's bitmapimage macros
Date: Wed, 1 Sep 2021 14:42:30 +0200	[thread overview]
Message-ID: <ca2889b3-d687-e2aa-3e8b-5c4910936c1f@xs4all.nl> (raw)
In-Reply-To: <CAKyqqaYXOPo+xWPp3ZS0QGouPB39uvg=eKK+w_VkGJFJyCQJMQ@mail.gmail.com>

On 9/1/2021 1:08 PM, Jairo A. del Rio via ntg-context wrote:
> Hi, list!
> I want to know if there's a handy way to pass predefined colors, either 
> RGB or CMYK, e.g. those in svg or crayola, to Metafun's bitmapimage. 
> Say, something like:
> 
> \startMPpage
> 
> % svg's gold definition
> 
> draw bitmapimage(2, 2, "ffd700 ffd700 ffd700 000000") scaled 3cm;
> 
> \stopMPpage
> 
> using "gold" instead of its definition so that I can set bitmap image 
> colors by name rather than numbers. In a similar vein, I wonder if 
> something analogous is possible for ConTeXt's \bitmapimage macro. Thank 
> you in advance.
it's mostly about 'what interface to use' and 'how is that documented 
and remembered at all'

\startluacode
     function MP.replacecolors(str,c)
         -- could be a helper, these two combined (never needed it):
         local m, a = attributes.colors.namedcolorattributes(c)
         local d = attributes.colors.values[a]
         local r = string.format("%02x%02x%02x",
             math.round(d[3]*255),
             math.round(d[4]*255),
             math.round(d[5]*255)
         )
         mp.quoted((string.gsub(str,"444444",r)))
     end
\stopluacode

\definecolor[kindofgold][h=ffd700]

\startMPpage

draw bitmapimage(2, 2, "ffd700 ffd700 ffd700 000000") scaled 3cm;

vardef mybitmapimage(expr n, m, s, c) =
     bitmapimage(2, 2, MP.replacecolors(s, c))
enddef ;

draw mybitmapimage(2, 2, "444444 444444 444444 000000", "kindofgold") 
scaled 3cm shifted (0,-3cm);

\stopMPpage




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      reply	other threads:[~2021-09-01 12:42 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-01 11:08 Jairo A. del Rio via ntg-context
2021-09-01 12:42 ` Hans Hagen via ntg-context [this message]

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