metaobj and transparent colors with \MPcolor

metaobj and transparent colors with \MPcolor

[Eckhart Guthöhrlein]

Hi,

I try to achieve transparently filled objects using the metaobj package.
However, transparency is ignored completely in the output, I just get a
normal white. Here is my test file:

\setupcolors[state=start]
\setupbackgrounds[page][background=color,backgroundcolor=red]

\startMPenvironment[global]
  \definecolor[Durchsichtig][r=1.0,g=1.0,b=1.0,t=0.0,a=normal]
\stopMPenvironment

\startreusableMPgraphic{test}
	input metaobj;
	setObjectDefaultOption("Box")("fillcolor")(\MPcolor{Durchsichtig});
	newBox.test(btex Transparent? etex) "filled(true)";
	Obj(test).c=origin;
	drawObj(test);
\stopreusableMPgraphic

\starttext
	\reuseMPgraphic{test}
\stoptext


If I use the fillcolor as an argument to the object

	newBox.test(btex Transparent? etex) "filled(true)"
		"fillcolor(\MPcolor{Durchsichtig})";

I get error messages from the mpost run. So it seems that metaobj and
\MPcolor don't like each other.
Any ideas how to circumvent this problem?

Regards,
Eckhart

Re: metaobj and transparent colors with \MPcolor

[Vit Zyka]

Sorry, I can not reproduce your example. I get only red page with black 
page number in header. No white box. And I do not known metaobj macro.

But I have a question. It is really needed to surround \definecolor by 
\startMPenvironment? Since \definecolor has to result to \pdfobj and 
\pdfliteral (pdftex primitives) and propagation to mpost (which is EPS 
not PDF generator) has no sence. Only reference to color is needed and 
it is done via \MPcolor. Am I right?

Vit Zyka

> I try to achieve transparently filled objects using the metaobj package.
> However, transparency is ignored completely in the output, I just get a
> normal white. Here is my test file:
> 
> \setupcolors[state=start]
> \setupbackgrounds[page][background=color,backgroundcolor=red]
> 
> \startMPenvironment[global]
>   \definecolor[Durchsichtig][r=1.0,g=1.0,b=1.0,t=0.0,a=normal]
> \stopMPenvironment
> 
> \startreusableMPgraphic{test}
> 	input metaobj;
> 	setObjectDefaultOption("Box")("fillcolor")(\MPcolor{Durchsichtig});
> 	newBox.test(btex Transparent? etex) "filled(true)";
> 	Obj(test).c=origin;
> 	drawObj(test);
> \stopreusableMPgraphic
> 
> \starttext
> 	\reuseMPgraphic{test}
> \stoptext
> 
> 
> If I use the fillcolor as an argument to the object
> 
> 	newBox.test(btex Transparent? etex) "filled(true)"
> 		"fillcolor(\MPcolor{Durchsichtig})";
> 
> I get error messages from the mpost run. So it seems that metaobj and
> \MPcolor don't like each other.
> Any ideas how to circumvent this problem?
> 
> Regards,
> Eckhart

Re: metaobj and transparent colors with \MPcolor

[Eckhart Guthöhrlein]

On Fri, Jul 23, 2004 at 11:45:32AM +0200, Vit Zyka wrote:
> Sorry, I can not reproduce your example. I get only red page with black 
> page number in header. No white box. And I do not known metaobj macro.

The graphics won't compile without metaobj, which is a very nice macro
package for metapost, available at
CTAN/graphics/metapost/contrib/macros/metaobj/

> But I have a question. It is really needed to surround \definecolor by 
> \startMPenvironment? Since \definecolor has to result to \pdfobj and 
> \pdfliteral (pdftex primitives) and propagation to mpost (which is EPS 
> not PDF generator) has no sence. Only reference to color is needed and 
> it is done via \MPcolor. Am I right?

During a texexec run, inline MP graphics are automatically generated and
converted in case of PDF output, provided that you have configured your
texexec to do so.
Definitions enclosed in \startMPenvironment ... \stopMPenvironment are
made available not only inside MP graphics, but also for the main
document by the [global] option. In this case, I use it to maintainn
color consistency between metapost and tex.
Without \startMPenvironment, the color definition would be available in
context only, not for inline graphics.

-- 
Eckhart

Re: metaobj and transparent colors with \MPcolor

[Hans Hagen Outside]

Vit Zyka wrote:

> Sorry, I can not reproduce your example. I get only red page with 
> black page number in header. No white box. And I do not known metaobj 
> macro.
>
> But I have a question. It is really needed to surround \definecolor by 
> \startMPenvironment? Since \definecolor has to result to \pdfobj and 
> \pdfliteral (pdftex primitives) and propagation to mpost (which is EPS 
> not PDF generator) has no sence. Only reference to color is needed and 
> it is done via \MPcolor. Am I right?

only things that are needed in btex ... etex or textext(..) need to be 
put into \startMPenvironment, so in your case the color def can stay 
outside the env.

> Vit Zyka
>
>> I try to achieve transparently filled objects using the metaobj package.
>> However, transparency is ignored completely in the output, I just get a
>> normal white. Here is my test file:
>>
>> \setupcolors[state=start]
>> \setupbackgrounds[page][background=color,backgroundcolor=red]
>>
>> \startMPenvironment[global]
>>   \definecolor[Durchsichtig][r=1.0,g=1.0,b=1.0,t=0.0,a=normal]
>> \stopMPenvironment
>>
>> \startreusableMPgraphic{test}
>>     input metaobj;
>>     setObjectDefaultOption("Box")("fillcolor")(\MPcolor{Durchsichtig});
>>     newBox.test(btex Transparent? etex) "filled(true)";
>>     Obj(test).c=origin;
>>     drawObj(test);
>> \stopreusableMPgraphic
>>
>> \starttext
>>     \reuseMPgraphic{test}
>> \stoptext
>>
>>
>> If I use the fillcolor as an argument to the object
>>
>>     newBox.test(btex Transparent? etex) "filled(true)"
>>         "fillcolor(\MPcolor{Durchsichtig})";
>
can you try
                 fillcolor \MPcolor{...}

or maybe

color xxxx ; xxxx := \MPcolor{...} ; fillcolor(xxxx) ;

>>
>> I get error messages from the mpost run. So it seems that metaobj and
>> \MPcolor don't like each other.
>> Any ideas how to circumvent this problem?
>>
>> Regards,
>> Eckhart
>
>
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-- 

-----------------------------------------------------------------
                                          Hans Hagen | PRAGMA ADE
              Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
     tel: 038 477 53 69 | fax: 038 477 53 74 | www.pragma-ade.com
                                             | www.pragma-pod.nl
-----------------------------------------------------------------

Re: metaobj and transparent colors with \MPcolor

[Denis Roegel]

On Fri, Jul 23, 2004 at 09:53:22AM +0200, Eckhart Guthöhrlein wrote:
> Hi,
> 
> I try to achieve transparently filled objects using the metaobj package.
> However, transparency is ignored completely in the output, I just get a
> normal white. Here is my test file:
>

Hi,

I have never considered transparency in metaobj, and each part of an object
is merely drawn, in some order depending on that object, and with some (opaque) color.
It seems some serious surgery would be needed to seamlessly add transparency
handling. It can certainly be done, be it only by working on an object
structure, but I don't see a quick fix.

Denis Roegel

Re: metaobj and transparent colors with \MPcolor

[Hans Hagen Outside]

Denis Roegel wrote:

>On Fri, Jul 23, 2004 at 09:53:22AM +0200, Eckhart Guthöhrlein wrote:
>  
>
>>Hi,
>>
>>I try to achieve transparently filled objects using the metaobj package.
>>However, transparency is ignored completely in the output, I just get a
>>normal white. Here is my test file:
>>
>>    
>>
>
>Hi,
>
>I have never considered transparency in metaobj, and each part of an object
>is merely drawn, in some order depending on that object, and with some (opaque) color.
>It seems some serious surgery would be needed to seamlessly add transparency
>handling. It can certainly be done, be it only by working on an object
>structure, but I don't see a quick fix.
>  
>
no, transparency is handled by the colors themselves so if metaobj can carry along a color it's should work ok 

Hans 

-----------------------------------------------------------------
                                          Hans Hagen | PRAGMA ADE
              Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
     tel: 038 477 53 69 | fax: 038 477 53 74 | www.pragma-ade.com
                                             | www.pragma-pod.nl
-----------------------------------------------------------------

Re: metaobj and transparent colors with \MPcolor

[Vit Zyka]

>>Sorry, I can not reproduce your example. I get only red page with black 
>>page number in header. No white box. And I do not known metaobj macro.
> 
> The graphics won't compile without metaobj, which is a very nice macro
> package for metapost, available at
> CTAN/graphics/metapost/contrib/macros/metaobj/

I, of course, checked if the package metaobj is installed and loaded. 
Perhaps my is too old (v0.83)?

I had a look to metaobj manual and it is good to know about it.
Thank you.

Vit Zyka

Re: metaobj and transparent colors with \MPcolor

[Eckhart Guthöhrlein]

On Sat, Jul 24, 2004 at 11:28:36AM +0200, Vit Zyka wrote:
> I, of course, checked if the package metaobj is installed and loaded. 
> Perhaps my is too old (v0.83)?

That's the current version.

-- 
Eckhart

Re: metaobj and transparent colors with \MPcolor

[Eckhart Guthöhrlein]

On Fri, Jul 23, 2004 at 11:38:28AM -0700, Hans Hagen Outside wrote:
> >>If I use the fillcolor as an argument to the object
> >>
> >>    newBox.test(btex Transparent? etex) "filled(true)"
> >>        "fillcolor(\MPcolor{Durchsichtig})";
> >
> can you try
>                 fillcolor \MPcolor{...}
> 
> or maybe
> 
> color xxxx ; xxxx := \MPcolor{...} ; fillcolor(xxxx) ;

Here is my current file, which just gives a white background in the box.

\setupcolors[state=start]
\setupbackgrounds[page][background=color,backgroundcolor=red]
\definecolor[Transparent][r=0,g=1,b=1,t=0,a=normal]
\startreusableMPgraphic{test}
	input metaobj;
	color t; t:=\MPcolor{Transparent};
	setObjectDefaultOption("Box")("fillcolor")(t);
	newBox.test(btex Transparent? etex) "filled(true)";
	Obj(test).c=origin;
	drawObj(test);
\stopreusableMPgraphic
\starttext
	\reuseMPgraphic{test}
\stoptext

Experimenting with default degrees of transparency, e.g. t=0.5, I have
noticed that the object is indeed filled using the Transparent color.
The problem seems to be that all objects in metaobj are filled using a
non-transparent white by default. Subsequent filling with a completely
transparent color then of course gives just white.
Well, I just want to see my normal page background through the object.
Can I achieve this?

-- 
Eckhart

Re: metaobj and transparent colors with \MPcolor

[Hans Hagen]

Eckhart Guthöhrlein wrote:

>The problem seems to be that all objects in metaobj are filled using a
>non-transparent white by default. Subsequent filling with a completely
>transparent color then of course gives just white.
>  
>
ah, maybe denis uses the metapost 'backgroundcolor' which is white; i'd say: never use that ! just don't fill! 

btw, i recently introduced nocolor, being (-1,-1,-1) 

Hans   

-----------------------------------------------------------------
                                          Hans Hagen | PRAGMA ADE
              Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
     tel: 038 477 53 69 | fax: 038 477 53 74 | www.pragma-ade.com
                                             | www.pragma-pod.nl
-----------------------------------------------------------------

Re: metaobj and transparent colors with \MPcolor

[Eckhart Guthöhrlein]

On Fri, Jul 30, 2004 at 12:08:33PM +0200, Vit Zyka wrote:
> >Here is my current file, which just gives a white background in the box.
> >
> >\setupcolors[state=start]
> >\setupbackgrounds[page][background=color,backgroundcolor=red]
> >\definecolor[Transparent][r=0,g=1,b=1,t=0,a=normal]
> >\startreusableMPgraphic{test}
> >	input metaobj;
> >	color t; t:=\MPcolor{Transparent};
> >	setObjectDefaultOption("Box")("fillcolor")(t);
> >	newBox.test(btex Transparent? etex) "filled(true)";
> >	Obj(test).c=origin;
> >	drawObj(test);
> >\stopreusableMPgraphic
> >\starttext
> >	\reuseMPgraphic{test}
> >\stoptext
> 
> Sorry I still do not see your white box. Perhaps something is corrupted 
> in my context installation.
> 
> I had a quick look into mpobj source and I tried to remove default white 
> background, but I was not successful.

Me either.

> Vit Zyka
> 
> P.S. I played with raw MP code:
> 
> input metaobj;
> beginfig(1)
>   fill fullcircle scaled 1cm withcolor red;
> 	color t; t:=(1,1,0);
> 	%setObjectDefaultOption("Box")("fillcolor")(t);
> 	newBox.test("");
> 	Obj(test).c=origin;
> 	drawObj(test);
> endfig;
> 
> end.

Your color is not transparent, so it will work as expected: no white
box.

-- 
Eckhart

Re: metaobj and transparent colors with \MPcolor

[Eckhart Guthöhrlein]

On Mon, Aug 02, 2004 at 01:20:27PM +0200, Vit Zyka wrote:
> >>input metaobj;
> >>beginfig(1)
> >> fill fullcircle scaled 1cm withcolor red;
> >>	color t; t:=(1,1,0);
> >>	%setObjectDefaultOption("Box")("fillcolor")(t);
> >>	newBox.test("");
> >>	Obj(test).c=origin;
> >>	drawObj(test);
> >>endfig;
> >>
> >>end.
> >
> >Your color is not transparent, so it will work as expected: no white
> >box.
> 
> ???
> 
> The example demonstrated that it *IS* drawn white box in the background 
> of every metaobj object. Exactly as you mentioned.

Yes of course. Sorry.

> But I had a second look into mpobj.mp and probably find out the white 
> box tiger. Comment line 750:
>   unfill BpathObj(n);
> I am sure this hack will cause some unpleasant side-effects (e.g. with 
> shaded boxes) but in some limited situations...

Indeed, the hack works for me. Thank you very much for your time and
effort!

-- 
Eckhart