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diff --git a/doc/context/sources/general/manuals/metafun/metafun-examples.tex b/doc/context/sources/general/manuals/metafun/metafun-examples.tex index 4e5e0eed3..5549a3bdd 100644 --- a/doc/context/sources/general/manuals/metafun/metafun-examples.tex +++ b/doc/context/sources/general/manuals/metafun/metafun-examples.tex @@ -3264,6 +3264,259 @@ We get: \stopsection +\startsection[title=Educational] + +I made this example long ago, when some family member had to learn tables by +heart. For some reason, at school, this is made into a complex issue, with tricks +and such, even it if only involves only a few numbers. My own experience (if I +remember right) was that some of these numbers are trivial, and that there is +quite some symmetry, so in practice only a quarter needs to be remembered. And, +assuming that you can easily deduct the trivial cases, one can just calculate the +rest if needed. + +\startbuffer +\start \ttbf \startMPcode + def MyDraw(expr i, j, c) = + fill fullsquare shifted (i,j) withcolor c withtransparency (1,.5) ; + enddef ; + + for i = 1 upto 10 : + for j = 1 upto 10 : MyDraw( i, -j, "middlered" ) ; endfor ; endfor ; + + for j = 1 upto 10 : MyDraw( 1, -j, "middleblue" ) ; endfor ; + for i = 1 upto 10 : MyDraw( i, -10, "middlegreen" ) ; endfor ; + for i = 1 upto 10 : MyDraw( i, -1, "middleyellow") ; endfor ; + for j = 1 upto 10 : MyDraw(10, -j, "middlecyan" ) ; endfor ; + for j = 1 upto 10 : MyDraw( 5, -j, "middlegray" ) ; endfor ; + for j = 1 upto 10 : MyDraw( j, -j, "middlegray" ) ; endfor ; + + draw image ( for i = 1 upto 10 : for j = 1 upto 10 : + draw textext(decimal (i*j)) ysized .25 shifted (i,-j) ; + endfor ; endfor ; ) withcolor white ; + + currentpicture := currentpicture ysized 10cm ; +\stopMPcode \stop +\stopbuffer + +\typebuffer + +\startplacefigure[title=Overlapping glyphs,reference=fig:tentable] + \getbuffer +\stopplacefigure + +Here we use both transparency and colors to stress the reduction of cases. The +named colors resolve to ones defined at the \TEX\ end. We see the redndering +\in {figure} [fig:tentable]. + +\startsection[title=Glyph magic] + +The next example is the result of a tread on the mailing list. After Henri Menke +posted a some glyph overlap code, I made a variant that more suited the way we do +it in \METAFUN. In the meantime Floris van Maanen had found out that some glyphs +need a more inventive solution so after that the code evolved. By then the \type +{outlinetext}, \type {drawoutlinetext} and \type {filloutlinetext} helpers had +been added to the code base. + +Because this is complicated stuff, we just show the two solutions. The first one +is a relative simple one, the second one uses an approach suggested by Alan +Braslau and therefore uses some of the code that can be found in the \type +{crossingunder} macro. + +\startbuffer +\startMPdefinitions +def ShowOverlapInOutlinesA(expr first, second) = + path p_i, p_j, s_i, s_j ; + numeric n_i, n_j, index ; + pair found ; + index := 0 ; + for i within first : + for j within second : + p_i := pathpart i ; n_i := length(p_i) ; + p_j := pathpart j ; n_j := length(p_j) ; + for ii = 0 upto n_i - 1 : + s_i := subpath(ii,ii+1) of p_i ; + for jj = 0 upto n_j - 1 : + s_j := subpath(jj,jj+1) of p_j ; + found := s_i intersection_point s_j ; + if intersection_found : + index := index + 1 ; + drawdot found + withpen pencircle scaled 4 withcolor white ; + draw textext("\strut\ttbf " & decimal index) ysized 3 + shifted found ; + fi ; + endfor ; + endfor ; + endfor ; + endfor ; +enddef ; +\stopMPdefinitions +\stopbuffer + +\typebuffer \getbuffer + +This is the solution based on \type {crossingunder}, a macro that has been +introduced as part of Alan's neat node module. + +\startbuffer +\startMPdefinitions +def ShowOverlapInOutlinesB(expr first, second) = + begingroup ; + save p, q, n, t, a, b, c, bcuttings, hold, found ; + path p, q ; + numeric n, hold ; + path a, b, c, bcuttings ; + pair found ; + c := makepath(currentpen scaled crossingscale) ; + for f within first : + numeric t[]; + path hold[]; + t[0] := n := hold := 0 ; + for s within second : + p := pathpart f ; + q := pathpart s ; + a := p ; + for i=1 upto crossingnumbermax : % safeguard + clearxy ; z = a intersectiontimes q ; + if x < 0 : + exitif hold < 1 ; + a := hold[hold] ; hold := hold - 1 ; + clearxy ; z = a intersectiontimes q ; + fi + (t[incr n], whatever) = p intersectiontimes point x of a ; + if x = 0 : + a := a cutbefore c shifted point x of a ; + elseif x = length a : + a := a cutafter c shifted point x of a ; + else : % before or after? + b := subpath (0,x) of a cutafter c shifted point x of a ; + bcuttings := cuttings ; + a := subpath (x,length a) of a cutbefore c shifted point x of a ; + clearxy ; z = a intersectiontimes q ; + if x < 0 : + a := b ; + cuttings := bcuttings ; + elseif length bcuttings > 0 : + clearxy ; z = b intersectiontimes q ; + if x >= 0 : + hold[incr hold] := b ; + fi + fi + fi + if length cuttings = 0 : + exitif hold < 1 ; + a := hold[hold] ; hold := hold - 1 ; + fi + endfor ; + endfor ; + t[incr n] = length p ; + for i=1 upto n : + found := point t[i] of p ; + drawdot found + withpen pencircle scaled 4 withcolor white ; + draw textext("\strut\ttbf " & decimal i) ysized 3 + shifted found ; + endfor ; + endfor ; + endgroup ; +enddef ; +\stopMPdefinitions +\stopbuffer + +\typebuffer \getbuffer + +We demonstrate the differences with an example. The result can be seen in +\in {figure} [fig:overlapping:a]. + +\startbuffer +\startcombination + {\startMPcode + picture first, second ; + first := outlinetext.p("N") ; first := first scaled 10 ; + second := outlinetext.p("T") ; second := second scaled 10 ; + second := second rotatedaround(center second, 5) shifted (1,-1) ; + filloutlinetext(first ) withcolor .5[darkblue,white] ; + filloutlinetext(second) withcolor .5[darkred,white] ; + drawoutlinetext(first ) ; + drawoutlinetext(second) ; + ShowOverlapInOutlinesA(first, second) ; + addbackground withcolor darkgray ; + currentpicture := currentpicture scaled 2.5 ; + \stopMPcode} {Method A} + {\startMPcode + picture first, second ; + first := outlinetext.p("N") ; first := first scaled 10 ; + second := outlinetext.p("T") ; second := second scaled 10 ; + second := second rotatedaround(center second, 5) shifted (1,-1) ; + filloutlinetext(first ) withcolor .5[darkgreen,white] ; + filloutlinetext(second) withcolor .5[darkyellow,white] ; + drawoutlinetext(first ) ; + drawoutlinetext(second) ; + ShowOverlapInOutlinesB(first, second) ; + addbackground withcolor darkgray ; + currentpicture := currentpicture scaled 2.5 ; + \stopMPcode} {Method B} +\stopcombination +\stopbuffer + +\typebuffer + +\startplacefigure[title=Overlapping glyphs,reference=fig:overlapping:a] + \getbuffer +\stopplacefigure + +We duplicate some code because the pictures will change in the process of +analyzing. Let's make a helper for that: + +\startbuffer +\startMPdefinitions +def ShowOverlap(expr f, s, m) = + picture first, second ; + first := outlinetext.p(f) ; first := first scaled 10 ; + second := outlinetext.p(s) ; second := second scaled 10 ; + + filloutlinetext(first ) withcolor darkblue ; + drawoutlinetext(first ) ; + + filloutlinetext(second) withcolor darkred ; + drawoutlinetext(second) ; + + if m == 2 : + ShowOverlapInOutlinesB + else : + ShowOverlapInOutlinesA + fi (first, second) ; + + addbackground withcolor darkgray ; + currentpicture := currentpicture ysized 4cm ; +enddef ; +\stopMPdefinitions +\stopbuffer + +\typebuffer \getbuffer + +Again we demonstrate the differences with some examples. The result can be seen in +\in {figure} [fig:overlapping:b]. + +\startbuffer + \startcombination[nx=3,ny=2] + {\startMPcode ShowOverlap("N","T",1) ; \stopMPcode} {Method 1} + {\startMPcode ShowOverlap("\$","Q",1) ; \stopMPcode} {Method 1} + {\startMPcode ShowOverlap("\tttf ABC","\tttf PQR",1) ; \stopMPcode} {Method 1} + {\startMPcode ShowOverlap("N","T",2) ; \stopMPcode} {Method 2} + {\startMPcode ShowOverlap("\$","Q",2) ; \stopMPcode} {Method 2} + {\startMPcode ShowOverlap("\tttf ABC","\tttf PQR",2) ; \stopMPcode} {Method 2} + \stopcombination +\stopbuffer + +\typebuffer + +\startplacefigure[title=Overlapping glyphs,reference=fig:overlapping:b] + \getbuffer +\stopplacefigure + +\stopsection + \stopchapter \stopcomponent |