From: Rik <rik@panix.com>
To: ntg-context@ntg.nl
Subject: Re: A better \definesymbol sought
Date: Mon, 23 Jan 2017 22:04:31 -0500 [thread overview]
Message-ID: <d8c40bf7-1b76-4f86-997c-ed6ce94d8704@panix.com> (raw)
In-Reply-To: <2117dc0b-6e30-c1fa-8b26-8eb2b6114b52@rik.users.panix.com>
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On 2017-01-23 14:09, Rik Kabel wrote:
> On 2017-01-23 00:06, Alan Braslau wrote:
> > On Sun, 22 Jan 2017 22:39:53 -0500 Rik Kabel > <context@rik.users.panix.com> wrote: > >> So, how can I make the
> inner glyph (‘?’ in the example below) >> transparent, so that the
> background shows through along with >> anything else that lives on a
> lower layer? I’ve seen a method for >> constructed shapes, but nothing
> that I can apply to text glyphs. >> Undraw doesn’t do it. > > Undraw
> is simply draw using the background color. > > Transparency is a
> MetaFun extension to MetaPost (so part of > ConTeXt). > > draw q
> withtransparency (1,0.5) ; % (method,transparency) > > Alan
>
> Hmmm. That does not work for me (with any of many method and
> transparency values). The ‘?’ is solid black. I do see a message in
> the log that looks related:
>
> mkiv lua stats > page group warning: transparencies are used but
> no pagecolormodel is set
>
> but adding \setcolors[state=start,cmyk=yes] does not change that; both
> the warning and the solid black glyph remain. Could this be an issue
> of the PDF viewer? Is it a font issue?
Okay, I got a clean compile using \definecolor and referencing that in
the MP page.
\setupbackgrounds
[page]
[background=color,backgroundcolor=yellow]
\definecolor[Transp][r=1,t=0,a=12]
\definefont
[DVSrB]
[file:DejaVuSerif-Bold.ttf]
\startuseMPgraphic{HeartTest 1}
picture h,q ;
h := "♥" infont "\truefontname{DejaVuSerif-Bold.ttf}" scaled 20 ;
q := textext("{\DVSrB ?}") scaled 10 ;
q := q shifted - (xpart center q, 12pt) ;
draw h withcolor blue ;
draw q withtransparency(12,0) ;
draw q shifted (72pt,0) withtransparency(12,0) ;
\stopuseMPgraphic
\startuseMPgraphic{HeartTest 2}
picture h,q ;
h := "♥" infont "\truefontname{DejaVuSerif-Bold.ttf}" scaled 20 ;
q := textext("\color[Transp]{\DVSrB ?}") scaled 10 ;
q := q shifted - (xpart center q, 12pt) ;
draw h withcolor blue ;
draw q ;
draw q shifted (72pt,0) ;
\stopuseMPgraphic
\starttext
\useMPgraphic{HeartTest 1}
\useMPgraphic{HeartTest 2}
\stoptext
Unfortunately, the result is not what I want. The result is that the “?”
disappears, allowing the color directly behind it to show through. The
example above shows that it works with \definecolor but not
withwithtransparency. I have no idea why, and certainly realize it could
be my error.
What I want is that the background of the page (yellow in this case)
should show through. That is what is done with fill / reverse / cycle,
as in:
\setupbackgrounds
[page]
[background=color,backgroundcolor=yellow]
\startuseMPgraphic{CircleTest}
path p,q ;
p := fullcircle scaled 2cm ;
q := fullcircle scaled 1cm ;
fill p -- reverse q -- cycle withcolor blue;
\stopuseMPgraphic
\starttext
\useMPgraphic{CircleTest}
\stoptext
where the background color (yellow) comes through the inner circle (path q).
Can this be done with text characters? I suspect that the answer is that
the glyphs have to be converted to paths and that it will only work when
there are no islands (as in ‘P’).
--
Rik
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next prev parent reply other threads:[~2017-01-24 3:04 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-21 3:33 Rik Kabel
2017-01-21 4:54 ` Alan Braslau
2017-01-23 3:39 ` Rik Kabel
2017-01-23 5:06 ` Alan Braslau
2017-01-23 19:09 ` Rik Kabel
2017-01-24 3:04 ` Rik [this message]
2017-01-24 8:34 ` Hans Hagen
2017-01-24 19:01 ` Rik Kabel
2017-01-25 10:17 ` Hans Hagen
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