[NTG-context] metafun / patterns

25 Mar 2021

      Hi,

As I'm still in metafun (and svg) mode I decided to support patterns 
(that are already supported at the tex end) also in metafun. As there 
has never been demands I suppose it's not that interesting but it sort 
of fits in.

There are some tricky aspectx involved so the interface might evolve a 
bit (some more control options) but here are some examples anyway:

\starttext

\startMPpage[offset=1cm]
     draw (fullcircle scaled 5cm shifted (0cm,0cm))
         withpattern image (fill fullcircle scaled 1cm withcolor 
"darkblue" ;)
         withpatternscale (1/10,1/10)
     ;

     draw (fullcircle scaled 5cm shifted (5cm,0cm))
         withpattern image (fill fullcircle scaled 5mm withcolor 
"darkred" ;)
         withpatternscale (1/20,1/20)
     ;

     draw (fullcircle scaled 5cm shifted (10cm,0cm))
         withpattern image (fill fullcircle scaled 5mm withcolor 
"darkgreen" ;)
         withpatternscale (1/40,1/40)
     ;

     draw (fullcircle scaled 5cm shifted (0cm,5cm))
         withpattern image (fill fullcircle scaled 1cm withcolor 
"darkcyan" ;)
         withpatternscale (1/10,1/20)
     ;

     draw (fullcircle scaled 5cm shifted (5cm,5cm))
         withpattern image (fill fullcircle scaled 5mm withcolor 
"darkmagenta" ;)
         withpatternscale (1/20,1/40)
     ;

     draw (fullcircle scaled 5cm shifted (10cm,5cm))
         withpattern image (fill fullcircle scaled 5mm withcolor 
"darkyellow" ;)
         withpatternscale (1/40,1/80)
     ;
\stopMPpage

\startMPpage[offset=1cm]
     fill fullcircle scaled 11cm
         withcolor "darkyellow" ;

     draw fullcircle scaled 10cm
         withpattern image (fill fullcircle scaled 1cm withcolor 
"darkblue" ;)
     ;

     draw fulldiamond scaled 8cm
         withpattern image (fill fulldiamond scaled 4mm withcolor 
"darkgreen" ;)
         rotated 15
     ;

     draw fulltriangle scaled 9cm
         withpattern image (fill fulltriangle scaled 3mm withcolor 
"white" ;)
         rotated 45
     ;

     draw fullcircle scaled 10cm
         withpattern image (draw textext("!") withcolor "middlegray" ;)
         rotated 45
     ;

     draw fullcircle scaled 10cm
         withpen pencircle scaled 1mm
         withcolor "darkgray" ;
\stopMPpage

\startMPpage[instance=doublefun]
     draw closedcurve(unitsquare xyscaled (200,200) shifted (0,-200))
         withpattern image (fill closedcurve((fullcircle scaled 40 
shifted (25,-25))) withcolor "darkgray" withopacity .5)
         withpatternscale (1,1)
     ;
     draw closedcurve(unitsquare xyscaled (200,200) shifted (0,-200))
         withpattern image (fill closedcurve((fullcircle scaled 40 
shifted (25,-25))) withcolor "darkred" withopacity .5)
         withpatternscale (1/2,1/2)
     ;
     draw closedcurve(unitsquare xyscaled (200,200) shifted (0,-200))
         withpattern image (fill closedcurve((fullcircle scaled 40 
shifted (25,-25))) withcolor "darkgreen" withopacity .5)
         withpatternscale (1/3,1/3)
     ;
     draw closedcurve(unitsquare xyscaled (200,200) shifted (0,-200))
         withpattern image (fill closedcurve((fullcircle scaled 40 
shifted (25,-25))) withcolor "darkblue" withopacity .5)
         withpatternscale (1/4,1/4)
     ;
\stopMPpage

% \startTEXpage
     \page
     \startMPcode{doublefun}
         draw closedcurve(unitsquare xyscaled (200,200) shifted (0,-400))
             withpattern image (fill closedcurve((fullcircle scaled 40 
shifted (25,-25))))
             withpatternscale (1/8,1/8)
         ;
     \stopMPcode
     \blank
     \startMPcode{doublefun}
         draw closedcurve(unitsquare xyscaled (200,200) shifted (0,-400))
             withpattern image (fill closedcurve((fullcircle scaled 40 
shifted (25,-25))))
             withpatternfloat true
             withpatternscale (1/8,1/8)
         ;
     \stopMPcode
     \page
% \stopTEXpage

% \startMPpage[instance=doublefun]

%   draw closedcurve(unitsquare xyscaled (200,200) shifted (0,-200))
%     withpattern image (   fill closedcurve(unitsquare xyscaled (50,50) 
shifted (0,-50))     withcolor svgcolor(0.529,0.808,0.922)   ;   fill 
closedcurve(unitsquare xyscaled (25,25) shifted (0,-25)) 
withshademethod "linear"
%     withshadecenteronefraction (0,1)
%     withshadecentertwofraction (0,0)
%     withshadestep ( withshadefraction 0.05 withshadecolors 
(svgcolor(1,0,0),svgcolor(1,0,0)) )
%     withshadestep ( withshadefraction 0.95 withshadecolors 
(svgcolor(1,0,0),svgcolor(1,0.5,0)) )   ;   fill closedcurve((fullcircle 
scaled 40 shifted (25,-25)))     withshademethod "linear"
%     withshadestep ( withshadefraction 0.05 withshadecolors 
(svggray(1),svggray(1)) )
%     withshadestep ( withshadefraction 0.95 withshadecolors 
(svggray(1),svgcolor(0,0,1)) )     withopacity 0.5   ; )
%     withpatternscale(1/4,1/4)
%   ;
% \stopMPpage

% \startTEXpage
%     \externalfigure[test.svg][conversion=mp,xobject=no]
% \stopTEXpage

\stoptext

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