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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