From: Hans Hagen <pragma@wxs.nl>
To: ntg-context@ntg.nl
Subject: Re: transparent colors
Date: Fri, 20 May 2016 10:50:53 +0200 [thread overview]
Message-ID: <2a9d78b1-c611-faac-f18b-2ce2cae0b9f7@wxs.nl> (raw)
In-Reply-To: <FB042CFB-9BE8-4C43-B21F-E437FC6C459E@uva.nl>
On 5/19/2016 10:35 PM, Meer, Hans van der wrote:
> With \definecolor[colorname][r=,g=,b=] one defines a color of name "colorname" for use in ConTeXt and in Metapost.
> A transparentcolor comes with \definecolor[transparentcolorname][r=,g=,b=,a=,t=]
>
> Problem: how to define a transparent color with \definetransparentcolor[#1][#2][#3]{...}.
> To be called for example as \definetransparentcolor[transparentcolorname][colorname][0.5] for color "colorname" with transparency 0.5.
>
> I tried to do this by intercepting from \definecolor the vales "r=,g=,b=" in a macro \colornamergb to be called as \csname..\endcsname for the varying colorname and feeding that to a definecolor-variant. However, the parsing of r=,g=,b= then goes wrong (\futurelet balking).
>
> Question: is there a direct way to derive a transparent colorvariant from a parent one without transparency? The usefulness of this comes from the fact that for things like \definecolor[lighthoneydew][r=.894117,g=.95,b=.894117] the numbers need not be feed more than once.
\starttext
\definespotcolor[redA][red][p=1]
\definespotcolor[redB][red][p=.5]
\definespotcolor[redC][redB][t=.5,a=1]
\definespotcolor[redD][redA][t=.25,a=1]
\redA test
\redB test
\redC test
\redD test
\stoptext
-----------------------------------------------------------------
Hans Hagen | PRAGMA ADE
Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
tel: 038 477 53 69 | www.pragma-ade.com | 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://tex.aanhet.net
archive : http://foundry.supelec.fr/projects/contextrev/
wiki : http://contextgarden.net
___________________________________________________________________________________
prev parent reply other threads:[~2016-05-20 8:50 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-19 20:35 Meer, Hans van der
2016-05-20 8:50 ` Hans Hagen [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=2a9d78b1-c611-faac-f18b-2ce2cae0b9f7@wxs.nl \
--to=pragma@wxs.nl \
--cc=ntg-context@ntg.nl \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).