\setupinteraction[state=start]
\usemodule[simpleslides]
	[style=swoosh]

\startuseMPgraphic{simpleslides:MP:counter}
	save b, s, t, p, circcenter, theta, pic ;
	path p[] ;
	pair t[] ;
	pair s[] ;
	pair circcenter ; 
	circcenter = urcorner Page shifted (-1cm,-1cm) ;
%	circcenter = lrcorner Page shifted (-1cm,1cm) ; 
	pair zt, zr, zb, zl ;
	picture pic ;
	b = 1.5cm ;
% the following if does not work in LMTX
%	if np > 2 : % the page after which the visual counter is shown
		theta = (PageNumber - 1)/(NOfPages - 1) ;
		p[4] = fullcircle scaled b rotated 90 ;
		p[4] := p[4] shifted circcenter ;
		fill p[4] withcolor \MPcolor{simpleslides:altcontrastcolor} ;
		t[0] = center p[4] ;
		t[1] = point 1 along p[4] ;
		t[2] = point -theta along p[4] ;
		t[3] = point -theta/2 along p[4] ;
		p[5] = t[0] -- t[1] .. t[3] .. t[2] -- cycle ;
		fill p[5] withcolor \MPcolor{simpleslides:contrastcolor} ;
		for i = 1 upto NOfPages :
			s[i] = point i/(NOfPages -1) along p[4] ;
			pickup pencircle scaled 1pt ;
			draw s[i] -- t[0] 
				withcolor \MPcolor{simpleslides:backgroundcolor} ;
		endfor ;
		zt = t[0] shifted (0, b * 0.2) ;
		zr = t[0] shifted (b * 0.2, 0) ;
		zb = t[0] shifted (0, -b * 0.2) ;
		zl = t[0] shifted (-b * 0.2, 0) ;
		p[3] = zt .. zr .. zb .. zl .. cycle ;
		fill p[3] withcolor  \MPcolor{simpleslides:contrastcolor} ;
		draw p[3] withcolor \MPcolor{simpleslides:backgroundcolor} ;
		label(textext("\start\switchtobodyfont[10pt]%
			\setupinteraction[color=simpleslides:backgroundcolor,style=normal]%
			\startcolor[simpleslides:backgroundcolor]
			\goto{\pagenumber}[PreviousJump]
			\stopcolor\stop"),center p[3]) ;
%	fi ;
\stopuseMPgraphic

\starttext

\setupTitle
	[title={Somewhere university},
	author={Someone Else},
	date={Somewhere, Someday 2021}]
\placeTitle

\page
\SlideTitle{Knuth} 

\input knuth.tex

\SlideTitle{Ward} 

\input ward.tex

\SlideTitle{Lorem} 

\input lorem.tex

\SlideTitle{Thuan} 

\input thuan.tex

\stoptext
