From: Marco Patzer <lists@homerow.info>
To: ntg-context@ntg.nl
Subject: Re: invert colors in \externalfigure
Date: Wed, 20 Jan 2016 14:09:41 +0100 [thread overview]
Message-ID: <20160120140941.395c862f@homerow> (raw)
In-Reply-To: <569F792F.5030701@gmx.es>
> How can I invert the colors in the external figure without having
> to edit the image file?
Based on Peter Münster's grph-downsample.lua here some lines that
should get you started. Note that you'll need graphicsmagick (or
imagemagick for that matter. In the latter case change the call from
`gm convert` to `convert`). This will do the conversion on the fly.
\startluacode
local format = string.format
local function invert(oldname, newname)
local s = format("gm convert -negate %s %s", oldname, newname)
os.execute(s)
end
local formats = {"png", "jpg", "gif"}
for _, s in ipairs(formats) do
figures.converters[s] = figures.converters[s] or {}
figures.converters[s]["invert." .. s] = invert
end
\stopluacode
\setupexternalfigures [conversion=invert.jpg]
\setupexternalfigures [location=default]
\starttext
\externalfigure[hacker]
\stoptext
Marco
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next prev parent reply other threads:[~2016-01-20 13:09 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-20 12:10 Pablo Rodriguez
2016-01-20 12:19 ` Wolfgang Schuster
2016-01-20 16:56 ` Pablo Rodriguez
2016-01-20 18:35 ` Alan BRASLAU
2016-01-22 20:39 ` Pablo Rodriguez
2016-01-20 13:09 ` Marco Patzer [this message]
2016-01-20 17:12 ` Pablo Rodriguez
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