vardef Foo( expr w, h, fillColor, fillTransparency) = =3D

show = "FOO:", w, h, fillColor, fillTransparency;

save pic; picture = pic;

save = circ; path circ;

circ = :=3D (fullcircle xyscaled (h,h));

pic :=3D image (

fill (circ shifted (w-h/2,-h/2)) = withcolor fillColor withtransparency = (1,fillTransparency);

);

pic

enddef;

picture pic;

pic :=3D 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=3Ddoublefun]
vardef Foo( = expr w, h, fillColor, fillTransparency) =3D
show = "FOO:", w, h, fillColor, fillTransparency;
save = pic; picture pic;
save circ; path circ;
circ :=3D (fullcircle xyscaled (h,h));
= pic :=3D image (
fill (circ shifted = (w-h/2,-h/2)) withcolor fillColor withtransparency fillTransparency;
);
pic
enddef;
pic :=3D 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=3Ddoublefun]

def withtransparency expr t =3D
=    if pair t :
=        withprescript = "tr_alternative=3D" & decimal = transparency_alternative_to_number(xpart t)
=        withprescript = "tr_transparency=3D" & decimal ypart t
=    else :
=        mfun_with_transparency = (transparency_alternative_to_number(t))
=    fi
enddef ;

def mfun_with_transparency (expr a) expr t =3D
=    withprescript "tr_alternative=3D" & decimal = a
   withprescript "tr_transparency=3D" = & decimal t
enddef ;

vardef= Foo ( expr w, h, fillColor, fillTransparency) =3D
= image (
   fill fullcircle xyscaled = (h,h) shifted (w-h/2,-h/2)
=        withcolor fillColor
       withtransparency = fillTransparency
   ;
= )
enddef;

vardef FooX ( = expr w, h, fillColor) =3D
image (
=    fill fullcircle xyscaled (h,h) shifted (w-h/2,-h/2)
       withcolor = fillColor
=        withtransparency = (normaltransparent, .5)
   ;
= )
enddef;

vardef FooY ( = expr w, h, fillColor) =3D
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

--

---------------------------------------------------------------= --
=             &n= bsp;           &nbs= p;            =     Hans Hagen | PRAGMA ADE
=             &n= bsp;Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
=       tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
---------------------------------------------------------------= --