It does not seem to work for all character combinations. e.g. B&T works, C&T works, C&M works, but N&T does not work. not N&M Why would that be? Thanks .Floris
> On 22 Sep 2018, at 11:27, Hans Hagen <j.ha...@xs4all.nl> wrote: > > On 9/22/2018 10:35 AM, Henri Menke wrote: >> Dear list, >> Challanged by a very old TeX.SX question >> https://tex.stackexchange.com/questions/180510 >> I wanted to calculate all the intersection points between two >> characters. Therefore I ripped off the \showshape macro to load the >> outlines from the font and convert them to MetaPost paths. Then I try >> to find all intersections by cutting the path. >> It somewhat works but for some reason, in the MWE below two intersection >> points are missing. I also have the feeling that my implementation is >> extremely inefficient. I would very much appreciate some hints by the >> MetaPost experts! >> Cheers, Henri >> --- >> \startluacode >> -- That's a simple reimplemetation of the showshape macro >> function outlinepaths(character) >> local fontid = font.current() >> local shapedata = fonts.hashes.shapes[fontid] -- by index >> local chardata = fonts.hashes.characters[fontid] -- by unicode >> local shapeglyphs = shapedata.glyphs or { } >> character = utf.byte(character) >> local c = chardata[character] >> if c then >> if not c.index then >> return {} >> end >> local glyph = shapeglyphs[c.index] >> if glyph and (glyph.segments or glyph.sequence) then >> local units = shapedata.units or 1000 >> local factor = 100/units >> local paths = fonts.metapost.paths(glyph,factor) >> return paths >> end >> end >> end >> \stopluacode >> \def\mpdefineoutlines#1#2{\ctxlua{ >> local char = "\luaescapestring{#1}" >> local outlines = outlinepaths("#2") >> local len = \letterhash outlines >> tex.print("path " .. char .. "[];") >> tex.print(char .. "n := " .. len .. ";") >> for i, path in ipairs(outlines) do >> tex.print(char .. "[" .. i .. "] := " .. path .. ";") >> end >> }} >> \starttext >> \startMPpage >> pair shift; shift := (1cm,-1cm); >> numeric angle; angle := 5; >> \mpdefineoutlines{B}{B} >> \mpdefineoutlines{T}{T} >> nofill B2; >> nofill B3; >> eofill B1 withcolor .5[blue,white]; >> fill T1 shifted (shift) rotated (angle) withcolor .5[red,white]; >> path r; >> numeric n; n := 0; >> for i = 1 upto Bn: >> for j = 1 upto Tn: >> r := B[i]; >> forever: >> pair q; >> r := r cutbefore (T[j] shifted (shift) rotated (angle)); >> exitif length cuttings = 0; >> r := subpath(epsilon, length r) of r; >> q = point 0 of r; >> n := n + 1; >> dotlabel.urt(textext("\tfx" & decimal n), q); >> endfor; >> endfor ; >> endfor ; >> \stopMPpage >> \stoptext > > You migh find more when you go top double mode .. anyway, these intersection > calculations are not that accurate so you normally need to apply some > overkill. > > - a bit cleaned up outlinepath function > - use document namespace > - add helper for defineoutline > - do 4 runs over the shapes (probably too many now) > - more neutral fill code > > It makes a nice example for the metafun (although then I'd do it slightly > different). We need some rounding becaus eotherwise you get similar points > (you can add a message(q) someplace). > > \startluacode > > function document.outlinepaths(character) > local chardata = fonts.hashes.characters[true] -- by unicode > local shapedata = fonts.hashes.shapes[true] -- by index > local c = chardata[character] > if c and c.index and shapedata then > local shapeglyphs = shapedata.glyphs or { } > local glyph = shapeglyphs[c.index] > if glyph and (glyph.segments or glyph.sequence) then > local units = shapedata.units or 1000 > local factor = 100/units > return fonts.metapost.paths(glyph,factor) > end > end > return { } > end > > function document.defineoutline(char,target) > local outlines = document.outlinepaths(char) > local nofpaths = #outlines > context("path %s[] ;",target) > context("numeric %sn ; %sn := %s ;",target,target,nofpaths) > for i=1,nofpaths do > context("%s[%i] := %s ; ",target,i,outlines[i]) > end > end > \stopluacode > > \def\mpdefineoutlines#1#2{\ctxlua{document.defineoutline(\number`#1,"#2")}} > > \starttext > > \startMPpage > pair shift ; shift := (1cm,-1cm); > numeric angle ; angle := 5; > > \mpdefineoutlines{B}{B} > \mpdefineoutlines{T}{T} > > for i=1 upto Bn - 1 : nofill B[i] ; endfor ; > eofill B[Bn] withcolor .5[blue,white] ; > > for i=1 upto Tn : > T[i] := T[i] shifted shift rotated angle ; > endfor ; > > for i=1 upto Tn - 1 : nofill T[i] ; endfor ; > eofill T[Tn] withcolor .5[red,white] ; > > pair found[] ; > boolean isnew ; > numeric n ; n := 0 ; > pair rq ; > > def GoForIt(expr how) = > path r ; > for i = 1 upto Bn : > for j = 1 upto Tn : > r := B[i] ; > forever: > pair q ; > if how = 1 : > r := r cutbefore T[j] ; > elseif how = 2 : > r := r cutbefore reverse T[j] ; > elseif how = 3 : > r := reverse r cutbefore T[j] ; > else : > r := reverse r cutbefore reverse T[j] ; > fi ; > exitif length cuttings = 0 ; > r := subpath(epsilon, length r) of r ; > q = point 0 of r ; > isnew := true ; > rq := round(q); > for f=1 upto n : > if found[f] = rq : > isnew := false ; > exitif true ; > fi ; > endfor ; > if isnew : > n := n + 1 ; > drawdot q withpen pencircle scaled 4 ; > draw textext("\strut\ttbf " & decimal n) ysized 3 shifted > q withcolor white ; > found[n] := rq ; > fi ; > endfor; > endfor ; > endfor ; > enddef ; > > for i=1 upto 4 : GoForIt(i) ; endfor ; > > \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 > ----------------------------------------------------------------- > ___________________________________________________________________________________ > 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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___________________________________________________________________________________ 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 ___________________________________________________________________________________
