On 10/5/2021 4:58 PM, Thomas A. Schmitz via ntg-context wrote:
Hi all,
I hope the following example is not too convoluted:
\useMPlibrary [txt]
\define\EmpArrow{\getscaledglyph{1.6}{name:dejavumath}{\char"2B05}}
\setupbodyfont [ss,9pt]
\starttext
\startuseMPgraphic{empedocles}
%numeric a ; a = 6.56cm ;
%numeric b ; b = 1.1 ;
save S; path S[] ;
S[1] = fullcircle scaled 8cm rotated 306 ;
S[2] = S[1] scaled 1.1 ;
S[3] = S[1] scaled 1.23 ;
S[4] = S[1] scaled 1.3 ;
S[5] = S[1] scaled 1.43 ;
S[6] = S[1] scaled 1.5 ;
S[7] = S[1] scaled 1.6 ;
z[1] = point 1 along S[7] ;
z[2] = point 1 along S[1] ;
z[3] = point 0.1 along S[7] ;
z[4] = point 0.1 along S[1] ;
z[5] = point 0.2 along S[7] ;
z[6] = point 0.2 along S[1] ;
z[7] = point 0.3 along S[7] ;
z[8] = point 0.3 along S[1] ;
z[9] = point 0.4 along S[7] ;
z[10] = point 0.4 along S[1] ;
z[11] = point 0.5 along S[7] ;
z[12] = point 0.5 along S[1] ;
z[13] = point 0.6 along S[7] ;
z[14] = point 0.6 along S[1] ;
z[15] = point 0.7 along S[7] ;
z[16] = point 0.7 along S[1] ;
z[17] = point 0.8 along S[7] ;
z[18] = point 0.8 along S[1] ;
S[8] = z[1] -- z[2] ;
S[9] = z[3] -- z[4] ;
S[10] = z[5] -- z[6] ;
S[11] = z[7] -- z[8] ;
S[12] = z[9] -- z[10] ;
S[13] = z[11] -- z[12] ;
S[14] = z[13] -- z[14] ;
S[15] = z[15] -- z[16] ;
S[16] = z[17] -- z[18] ;
z[19] = S[3] intersection_point S[8] ;
z[20] = S[3] intersection_point S[16] ;
S[18] = S[3] cutbefore z[20] cutafter z[19] ;
z[21] = S[5] intersection_point S[8] ;
z[22] = S[5] intersection_point S[16] ;
S[19] = S[5] cutbefore z[22] cutafter z[21] ;
z[23] = S[12] intersection_point S[3] ;
S[20] = S[3] cutbefore z[20] cutafter z[23] ;
for i = 1 upto 16:
draw S[i] withcolor 0.7white ;
endfor ;
draw z[23] -- z[20] withcolor red ;
draw S[20] withcolor blue ;
label.bot(textext("\noexpand\framed[align=middle,frame=off]{Jahr \crlf
20.000 = 0}"), z[10]) ;
label.llft(textext("\noexpand\framed[align=middle,frame=off]{Jahr \crlf
2.000}"), z[8]) ;
label.lft(textext("\noexpand\framed[align=middle,frame=off]{Jahr \crlf
4.000}"), z[6]) ;
label.lft(textext("\noexpand\framed[align=middle,frame=off]{Jahr \crlf
6.000}"), z[4]) ;
label.ulft(textext("\noexpand\framed[align=middle,frame=off]{Jahr \crlf
8.000}"), z[2]) ;
label.urt(textext("\noexpand\framed[align=middle,frame=off]{Jahr \crlf
12.000}"), z[18]) ;
label.rt(textext("\noexpand\framed[align=middle,frame=off]{Jahr \crlf
14.000}"), z[16]) ;
label.rt(textext("\noexpand\framed[align=middle,frame=off]{Jahr \crlf
16.000}"), z[14]) ;
label.lrt(textext("\noexpand\framed[align=middle,frame=off]{Jahr \crlf
18.000}"), z[12]) ;
draw followtext(S[18], "\strut\hbox to 2em{\EmpArrow}\hskip2em
RUHEPAUSE\hskip4em\strut") ;
draw followtext(S[19], "\strut\hbox to 2em{\EmpArrow}EINHEIT
(SPHAIROS)\hskip2em\strut") ;
\stopuseMPgraphic
\useMPgraphic{empedocles}
\stoptext
I have a big problem and some smaller questions, for those who are
better at math and at metafun than I am:
1. The big problem: for the next followtext, I need the circular arc
between points z[23] and z[20]. But however I place the cutbefore and
cutafter, I don't get the proper part of the circle. I'm looking at the
right intersection points, as the red line shows, but the blue line
shows that I'm not getting the right section of the circle. How can I
get this section into the path S[20]?
2. Math... :-) Is there a better way to define three circles that are at
exactly the same distance than my naive "scaled 1.3" and "scaled 1.5"?
3. TeX and metafun: is there a better way to have the followtext exactly
centered between the two circles rather than just fiddle with the scale
factor?
4. Or is there a better approach to my problem altogether? I'm trying to
reproduce an illustration from a book, so I'm very open to suggestions
here. I looked at the example in the metafun manual chapter 10.4, but
I'm not sure if using an overlay and multiple \followtokens would be
easier. Especially since there is the scary remark "This definition is
not the right one!" in this chapter without any further explanation.
I hope you all had a wonderful meeting last week. I was sad I couldn't
come, I was in Paris for a conference, the first after 18 months, so I
couldn't skip this one.
Because you know how to rotate and scale:
\startuseMPgraphic{empedocless}
path p, q, r ;
pair a ;
p := fullcircle scaled 10cm ;
drawarrow p withpen pencircle scaled 1mm withcolor red ;
drawpoint 0 of p withpen pencircle scaled 1mm withcolor blue ;
q := p cutafter (point .4 along p) ;
drawarrow q withpen pencircle scaled .5mm withcolor green ;
draw followtext(q, "\strut TEXT ONE") ;
p := fullcircle scaled 8cm ;
drawarrow p withpen pencircle scaled 1mm withcolor cyan ;
drawpoint 0 of p withpen pencircle scaled 1mm withcolor magenta ;
q := p cutafter (point .3 along p) ;
q := q rotated 120 ;
drawarrow q withpen pencircle scaled .5mm withcolor yellow ;
draw followtext(q,
