From: Marco <netuse@lavabit.com>
To: ntg-context@ntg.nl
Subject: Re: drawarrow and transparency
Date: Wed, 2 May 2012 21:42:24 +0200 [thread overview]
Message-ID: <20120502214224.754fa3ab@Zewz> (raw)
In-Reply-To: <20120502173518.604e1545@sole.extra.cea.fr>
On 2012-05-02 Alan BRASLAU <alan.braslau@cea.fr> wrote:
> For example, in the minimal example below, how can one obtain
> a transparent arrow without getting an X-ray vision of the
> arrowhead?
Maybe I'm reinventing the wheel here, but you can write a small
macro that only draws the lines you want. Here is an idea:
\starttext
\startMPpage
linecap := squared;
penscale := .5bp;
pickup pencircle scaled penscale;
def drawmyarrow expr p = _apth:=p; _myfinarr enddef;
def _myfinarr text t =
draw _apth cutafter point (-ahlength+.1penscale) on _apth t;
fill arrowhead _apth t
enddef;
drawarrow origin -- (1cm,0) withtransparency(1,.5) ;
drawarrow origin -- (0,1cm) withtransparency(1,.5) ;
drawmyarrow (1.5cm,0) -- (2.5cm,0) withtransparency(1,.5) ;
drawmyarrow (1.5cm,0) -- (1.5cm,1cm) withtransparency(1,.5) ;
\stopMPpage
\stoptext
The (-ahlength+.1penscale) are of course empiric. You should find
the correct formula to always have a nice match of line and arrow
whatever ahlength and ahangle values are in use.
Marco
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next prev parent reply other threads:[~2012-05-02 19:42 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-02 15:35 Alan BRASLAU
2012-05-02 19:42 ` Marco [this message]
2012-05-03 10:32 ` Alan BRASLAU
2012-05-03 12:47 ` Rogers, Michael K
2012-05-03 14:09 ` Peter Rolf
2012-05-05 9:19 ` Hans Hagen
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