* METAPOST/MetaFun withtransparency doesn't accept my pair primary argument, what am I doing wrong?
@ 2020-04-09 14:58 Gerben Wierda
2020-04-09 16:06 ` Hans Hagen
0 siblings, 1 reply; 3+ messages in thread
From: Gerben Wierda @ 2020-04-09 14:58 UTC (permalink / raw)
To: mailing list for ConTeXt users
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I have refactored my code to use withtransparency and separate parameters for colors, sizes, transparency, etc. But I’m running into a problem. The fillTransparency parameter is a pair primary (as can be seen from the show command)
Here is a pretty minimum example (in reality there are multiple colors and transparencies passed on):
\starttext
\startMPpage[instance=doublefun]
vardef Foo( expr w, h, fillColor, fillTransparency) =
show "FOO:", w, h, fillColor, fillTransparency;
save pic; picture pic;
save circ; path circ;
circ := (fullcircle xyscaled (h,h));
pic := image (
fill (circ shifted (w-h/2,-h/2)) withcolor fillColor withtransparency fillTransparency;
);
pic
enddef;
pic := Foo( 150, 50, (0.686,1.000,1.000), (1,1.000));
draw pic;
\stopMPpage
\stoptext
and the result is:
metapost log > >> "FOO:"
metapost log > >> 150
metapost log > >> 50
metapost log > >> (0.68600000000000005,1,1)
metapost log > >> (1,1)
metapost log > ! Missing argument to withtransparency.
metapost log > <to be read again>
metapost log > ((1,1))
metapost log > <argument> ...0000005,1,1))withtransparency((1,1))
metapost log > ;
metapost log > image->...ture;currentpicture:=nullpicture;(TEXT3)
metapost log > ;currentpicture.if.str(SUF...
metapost log >
metapost log > Foo->...)withcolor(EXPR4)withtransparency(EXPR5);)
metapost log > ;pic.endgroup
metapost log > <*> ...o( 150, 50, (0.686,1.000,1.000), (1,1.000))
metapost log > ; draw pic; ;
What am I doing wrong here?
Thanks,
G
PS. Given the complaint about asking both here and on tex.stackexchange, which of the two is the best place?
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: METAPOST/MetaFun withtransparency doesn't accept my pair primary argument, what am I doing wrong?
2020-04-09 14:58 METAPOST/MetaFun withtransparency doesn't accept my pair primary argument, what am I doing wrong? Gerben Wierda
@ 2020-04-09 16:06 ` Hans Hagen
2020-04-10 8:07 ` Gerben Wierda
0 siblings, 1 reply; 3+ messages in thread
From: Hans Hagen @ 2020-04-09 16:06 UTC (permalink / raw)
To: mailing list for ConTeXt users, Gerben Wierda
On 4/9/2020 4:58 PM, Gerben Wierda wrote:
> \starttext
> \startMPpage[instance=doublefun]
>
> vardef Foo( expr w, h, fillColor, fillTransparency) =
> show "FOO:", w, h, fillColor, fillTransparency;
> save pic; picture pic;
> save circ; path circ;
> circ := (fullcircle xyscaled (h,h));
> pic := image (
> fill (circ shifted (w-h/2,-h/2)) withcolor fillColor
> withtransparency fillTransparency;
> );
> pic
> enddef;
>
> pic := Foo( 150, 50, (0.686,1.000,1.000), (1,1.000));
> draw pic;
> \stopMPpage
> \stoptext
Maybe this definition is better then but I need to test it more
\starttext
\startMPpage[instance=doublefun]
def withtransparency expr t =
if pair t :
withprescript "tr_alternative=" & decimal
transparency_alternative_to_number(xpart t)
withprescript "tr_transparency=" & decimal ypart t
else :
mfun_with_transparency (transparency_alternative_to_number(t))
fi
enddef ;
def mfun_with_transparency (expr a) expr t =
withprescript "tr_alternative=" & decimal a
withprescript "tr_transparency=" & decimal t
enddef ;
vardef Foo ( expr w, h, fillColor, fillTransparency) =
image (
fill fullcircle xyscaled (h,h) shifted (w-h/2,-h/2)
withcolor fillColor
withtransparency fillTransparency
;
)
enddef;
vardef FooX ( expr w, h, fillColor) =
image (
fill fullcircle xyscaled (h,h) shifted (w-h/2,-h/2)
withcolor fillColor
withtransparency (normaltransparent, .5)
;
)
enddef;
vardef FooY ( expr w, h, fillColor) =
image (
fill fullcircle xyscaled (h,h) shifted (w-h/2,-h/2)
withcolor fillColor
withtransparency normaltransparent .5
;
)
enddef;
draw Foo ( 350, 50, (0.5,1,0), (1,.5));
draw FooX ( 250, 50, (1,0.5,1));
draw FooY ( 150, 50, (1,1,0.5));
\stopMPpage
\stoptext
--
-----------------------------------------------------------------
Hans Hagen | PRAGMA ADE
Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
-----------------------------------------------------------------
___________________________________________________________________________________
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maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
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___________________________________________________________________________________
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: METAPOST/MetaFun withtransparency doesn't accept my pair primary argument, what am I doing wrong?
2020-04-09 16:06 ` Hans Hagen
@ 2020-04-10 8:07 ` Gerben Wierda
0 siblings, 0 replies; 3+ messages in thread
From: Gerben Wierda @ 2020-04-10 8:07 UTC (permalink / raw)
To: Hans Hagen; +Cc: mailing list for ConTeXt users
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As I only use one transparency method anyway I could also fix this by passing a numeric instead of a pair and use the standard withtransparency (I don’t like overriding a standard MetaFun method, one never knows what might break in future updates).
vardef Foo( expr w, h, fillColor, fillTransparency) =
show "FOO:", w, h, fillColor, fillTransparency;
save pic; picture pic;
save circ; path circ;
circ := (fullcircle xyscaled (h,h));
pic := image (
fill (circ shifted (w-h/2,-h/2)) withcolor fillColor withtransparency (1,fillTransparency);
);
pic
enddef;
picture pic;
pic := Foo( 150, 50, (0.686,1.000,1.000), 0.5);
draw pic;
\stopMPpage
\stoptext
> On 9 Apr 2020, at 18:06, Hans Hagen <j.hagen@xs4all.nl> wrote:
>
> On 4/9/2020 4:58 PM, Gerben Wierda wrote:
>> \starttext
>> \startMPpage[instance=doublefun]
>> vardef Foo( expr w, h, fillColor, fillTransparency) =
>> show "FOO:", w, h, fillColor, fillTransparency;
>> save pic; picture pic;
>> save circ; path circ;
>> circ := (fullcircle xyscaled (h,h));
>> pic := image (
>> fill (circ shifted (w-h/2,-h/2)) withcolor fillColor withtransparency fillTransparency;
>> );
>> pic
>> enddef;
>> pic := Foo( 150, 50, (0.686,1.000,1.000), (1,1.000));
>> draw pic;
>> \stopMPpage
>> \stoptext
>
> Maybe this definition is better then but I need to test it more
>
> \starttext
> \startMPpage[instance=doublefun]
>
> def withtransparency expr t =
> if pair t :
> withprescript "tr_alternative=" & decimal transparency_alternative_to_number(xpart t)
> withprescript "tr_transparency=" & decimal ypart t
> else :
> mfun_with_transparency (transparency_alternative_to_number(t))
> fi
> enddef ;
>
> def mfun_with_transparency (expr a) expr t =
> withprescript "tr_alternative=" & decimal a
> withprescript "tr_transparency=" & decimal t
> enddef ;
>
> vardef Foo ( expr w, h, fillColor, fillTransparency) =
> image (
> fill fullcircle xyscaled (h,h) shifted (w-h/2,-h/2)
> withcolor fillColor
> withtransparency fillTransparency
> ;
> )
> enddef;
>
> vardef FooX ( expr w, h, fillColor) =
> image (
> fill fullcircle xyscaled (h,h) shifted (w-h/2,-h/2)
> withcolor fillColor
> withtransparency (normaltransparent, .5)
> ;
> )
> enddef;
>
> vardef FooY ( expr w, h, fillColor) =
> image (
> fill fullcircle xyscaled (h,h) shifted (w-h/2,-h/2)
> withcolor fillColor
> withtransparency normaltransparent .5
> ;
> )
> enddef;
>
> draw Foo ( 350, 50, (0.5,1,0), (1,.5));
> draw FooX ( 250, 50, (1,0.5,1));
> draw FooY ( 150, 50, (1,1,0.5));
>
> \stopMPpage
> \stoptext
>
>
> --
>
> -----------------------------------------------------------------
> Hans Hagen | PRAGMA ADE
> Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
> tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
> -----------------------------------------------------------------
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___________________________________________________________________________________
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://context.aanhet.net
archive : https://bitbucket.org/phg/context-mirror/commits/
wiki : http://contextgarden.net
___________________________________________________________________________________
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2020-04-09 14:58 METAPOST/MetaFun withtransparency doesn't accept my pair primary argument, what am I doing wrong? Gerben Wierda
2020-04-09 16:06 ` Hans Hagen
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