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diff --git a/doc/context/sources/general/manuals/still/still-profiling.tex b/doc/context/sources/general/manuals/still/still-profiling.tex new file mode 100644 index 000000000..8950864d6 --- /dev/null +++ b/doc/context/sources/general/manuals/still/still-profiling.tex @@ -0,0 +1,802 @@ +% language=uk + +\environment still-environment + +\enabledirectives[visualizers.fraction=2.5] + +\startcomponent still-profiling + +\startchapter[title=Profiling lines] + +\startsection[title=Introduction] + +Although \TEX\ is pretty good at typesetting simple texts like novels, in +practice it's often used for getting more complex stuff on paper (or screen). +Math is of course the first thing that comes to mind. If for instance you look at +the books typeset by Don Knuth you will see a rendering that is rather consistent +in spacing. This is no surprise as the author pays a lot of attention to detail +and uses inline versus display math properly. No publisher will complain about +the result. + +In the documents that I have to write styles for, the content is rather mixed, +and in particular inline math can have display math properties. In a one-column +layout this is not a real problem especially because lots of short sentences and +white space is used: we're talking of secondary|-|school educational math where +arguments for formatting something this or that way is not always rational and +consistent but more based on \quotation {this is what the student expects}, +\quotation {the competitor also does it that way} or just \quotation {we like +this more}. For instance in a recent project, the books with answers to questions +had to be typeset in a multicolumn layout and because math was involved, we end +up with lines with more height and depth than normal. That can not only result in +more pages but also can make the result look a bit messy. + +\blank \dontleavehmode \start \showboxes This paragraph demonstrates how lines +are handled: when a paragraph is broken into lines each line becomes a horizontal +box with a height and depth determined by the size of the characters that make up +the line. There is a minimal distance between baselines (\type {baselineskip}) +and when lines touch there can optionally be a \type {\lineskip}. In the end we +get a vertical list of boxes and glue (either of not flexible) mixed with +penalties that determine optimal paragraph breaks. This paragraph shows that +there is normally enough space available to do the job. \par \stop \blank + +We already have some ways to control this. For instance the dimensions of math +can be limited a bit and lines can be made to snap on a grid (which is what +publishers often want anyway). However, another alternative is to look at the +line and decide if successive lines can be moved closer, of course within the +constraints of the height and and depth of the lines. There is no real way to see +if some ugly clash can happen simply because when we run into boxed material +there can be anything inside and the dimensions can be set on purpose. This means +that we have to honour all dimensions and only can mess around with dimensions +when we're reasonably confident. In \CONTEXT\ this messing is called profiling +and that is what we will discuss next. + +\stopsection + +\startsection[title=Line heights and depths] + +\startbuffer[example-1] +Regelmatig kom je procenten tegen. ‘Pro centum’ is Latijn en betekent per +honderd, dus één van elke honderd, dus \math {\frac {1} {100}} deel. Met +procenten rekenen is daarom rekenen met honderdsten: \math {45 \procent = \frac +{45} {100} = 0,45}. Dus \math {45 \procent} van een geheel is het \math {\frac +{45} {100}} deel ervan en dat kun je berekenen door te vermenigvuldigen met \math +{0,45}. +\stopbuffer + +\startbuffer[example-2] +Je gaat uit van de bekende eigenschappen van machten. Bijvoorbeeld: \math {g^r * +g^s = g^{(r+s)}}. Neem je hierin \math {r = ^{g}\log(a)} en \math {s = ^{g}\log +b}, dan vind je: \math {g^{^{g}\log(a) + ^{g}\log(b)} = g^{^{g}\log a} \times +g^{^{g}\log b} = a \times b}. Hierbij gebruik je de definitieformules. +\stopbuffer + +\startbuffer[example-3] +Omdat volgens de eigenschappen van machten en exponenten geldt \math {\frac {1} +{x^4} = x^{-4} } is ook hier sprake van een machtsfunctie, namelijk \math {f(x) = +\frac {6} {x^4} = 6 \times \frac {1} {x^4} = 6x^{-4}}. +\stopbuffer + +In this section we will use some (Dutch) examples from documents that we've +processed. We show unprofiled versions, with two different paragraph widths, in +\in {figure} [fig:profiling:unprofiled-examples-widths]. All three examples shown +demonstrate that as soon as we use something more complex than a number or +variable in a subscript we exceed the normal line height, and thus the line +spacing becomes somewhat irregular. + +\starttexdefinition ExampleRunUnprofiled #1 + \vbox \bgroup + \switchtobodyfont[dejavu,10pt] + \raggedright + \hsize12cm + \inleft[scope=local]{\ttx hsize 12cm\\unprofiled} + \nl \vbox{\getbuffer[example-#1]} + \blank + \hsize10cm + \inleft[scope=local]{\ttx hsize 10cm\\unprofiled} + \nl \vbox{\getbuffer[example-#1]} + \egroup +\stoptexdefinition + +\startplacefigure[reference=fig:profiling:unprofiled-examples-widths,title={Unprofiled examples.}] + \enabletrackers[profiling.show] + \startcombination[nx=1,ny=3] + \startcontent + \ExampleRunUnprofiled{1} + \stopcontent + \startcaption + example 1 + \stopcaption + \startcontent + \ExampleRunUnprofiled{2} + \stopcontent + \startcaption + example 2 + \stopcaption + \startcontent + \ExampleRunUnprofiled{3} + \stopcontent + \startcaption + example 3 + \stopcaption + \stopcombination + \disabletrackers[profiling.show] +\stopplacefigure + +The profiled rendering of the same examples are shown in \in {figure} +[fig:profiling:profiled-examples-widths]. Here we use the minimal heights and +depths plus a minimum distance of 1pt. This default method is called \type +{strict}. + +\starttexdefinition ExampleRunProfiled #1 + \vbox \bgroup + \switchtobodyfont[dejavu,10pt] + \raggedright + \hsize12cm + \inleft[scope=local]{\ttx hsize 12cm\\profiled} + \nl \profiledbox{\getbuffer[example-#1]} + \blank + \hsize10cm + \inleft[scope=local]{\ttx hsize 10cm\\profiled} + \nl \profiledbox{\getbuffer[example-#1]} + \egroup +\stoptexdefinition + +\startplacefigure[reference=fig:profiling:profiled-examples-widths,title={Profiled examples.}] + \enabletrackers[profiling.show] + \startcombination[nx=1,ny=3] + \startcontent + \ExampleRunProfiled{1} + \stopcontent + \startcaption + example 1 + \stopcaption + \startcontent + \ExampleRunProfiled{2} + \stopcontent + \startcaption + example 2 + \stopcaption + \startcontent + \ExampleRunProfiled{3} + \stopcontent + \startcaption + example 3 + \stopcaption + \stopcombination + \disabletrackers[profiling.show] +\stopplacefigure + +In the first and last example there are some lines where the depth of one line +combined with the height of the following exceeds the standard line height. This +forces \TEX\ to insert \type {\lineskip} (mentioned in the demonstration +paragraph above), a dimension that is normally set to a fraction of the line +spacing (for instance 1pt for a 10pt body font and 12pt line spacing). When we +are profiling, \type{\lineskip} is ignored and we use a settable distance +instead. The second example (with superscripts) normally comes out fine as the +math stays within limits and we make sure that smaller fractions and scripts stay +within the natural limits of the line, but nested scripts can be an issue. + +% \unexpanded\def\fakeinmargin#1% +% {\dontleavehmode{\resetvisualizers\smash{\llap{#1}}}} + +% \unexpanded\def\fakestrut#1% +% {\fakeinmargin{\showstruts\strut\kern\dimexpr.5em+#1em/2\relax}} + +In \in {figure} [fig:profiling:zapf] we see the profile of a regular text with no +math. The average text stays well within the limits of height and depth. If this +doesn't happen for prose then you need to adapt the height|/|depth ratio to the +ascender|/|descender ratio of the bodyfont. For regular text it makes no sense to +use the profiler, it only slows down typesetting. + +\startplacefigure[reference=fig:profiling:zapf,title={Normal lines profiled (quote by Hermann Zapf)}] + \enabletrackers[profiling.show] + \switchtobodyfont[dejavu,10pt] + \profiledbox{\input{zapf}} + \disabletrackers[profiling.show] +\stopplacefigure + +\stopsection + +\startsection[title=When lines exceed boundaries] + +Let's now take a more detailed look at what happens when lines get too high or +low. First we'll zoom in on a simple example: in \in {figure} +[fig:profiling:simple-text], we compare a sample text rendered using the variants +of profiling currently implemented. (This is still experimental code so there +might be more in the future). Seeing profiles helps to get a picture of the +complications we have to deal with. In addition to the normal \type {vbox} +variant (used in the previous examples), we show \type {none} which only +analyzes, \type {strict} that uses the natural dimensions of lines and \type +{fixed} that is supposed to cooperate with grid snapping. + +% \startbuffer[fake-1] +% \hsize 2cm +% \fakestrut2 first x \par \fakestrut1 first y \blank +% \fakestrut2 second x \par \fakestrut1 second y \blank[2*big] +% \fakestrut2 third x \par \fakestrut1 third y \par +% \stopbuffer + +% \startbuffer[fake-2] +% \hsize 2cm +% \fakestrut2 line 1 \lower2ex\hbox{xxx}\par +% \fakestrut1 line 2 \raise2ex\hbox{xxx}\par +% \fakestrut2 line 3 \par +% \stopbuffer + +% \startplacefigure[reference=fig:profiling:simple-text,title={Just a simple two line text.}] +% \switchtobodyfont[10pt] +% \enabletrackers[profiling.show] +% \startcombination[nx=1,ny=3] +% \startcontent +% \startcombination[nx=4,ny=1,distance=10mm,style=\tt] +% {\kern1.5em\showboxes\vbox {\getbuffer[fake-1]}} {vbox} +% {\kern1.5em\showboxes\profiledbox[none] {\getbuffer[fake-1]}} {none} +% {\kern1.5em\showboxes\profiledbox[strict]{\getbuffer[fake-1]}} {strict} +% {\kern1.5em\showboxes\profiledbox[fixed] {\getbuffer[fake-1]}} {fixed} +% \stopcombination +% \stopcontent +% \startcaption +% no excessive height and depth +% \stopcaption +% \startcontent +% \startcombination[nx=4,ny=1,distance=10mm,style=\tt] +% {\kern1.5em\showboxes\vbox {\getbuffer[fake-2]}} {vbox} +% {\kern1.5em\showboxes\profiledbox[none] [distance=0pt]{\getbuffer[fake-2]}} {none} +% {\kern1.5em\showboxes\profiledbox[strict][distance=0pt]{\getbuffer[fake-2]}} {strict} +% {\kern1.5em\showboxes\profiledbox[fixed] [distance=0pt]{\getbuffer[fake-2]}} {fixed} +% \stopcombination +% \stopcontent +% \startcaption +% some excessive height and depth (distance=0pt) +% \stopcaption +% \startcontent +% \startcombination[nx=4,ny=1,distance=10mm,style=\tt] +% {\kern1.5em\showboxes\vbox {\getbuffer[fake-2]}} {vbox} +% {\kern1.5em\showboxes\profiledbox[none] [distance=2pt]{\getbuffer[fake-2]}} {none} +% {\kern1.5em\showboxes\profiledbox[strict][distance=2pt]{\getbuffer[fake-2]}} {strict} +% {\kern1.5em\showboxes\profiledbox[fixed] [distance=2pt]{\getbuffer[fake-2]}} {fixed} +% \stopcombination +% \stopcontent +% \startcaption +% some excessive height and depth (distance=2pt) +% \stopcaption +% \stopcombination +% \disabletrackers[profiling.show] +% \stopplacefigure + +\startbuffer[fake-1] +\hsize 2cm \dontleavehmode +line 1 \par +line 2 \par +line 3 \par +\stopbuffer + +\startbuffer[fake-2] +\hsize 2cm \dontleavehmode +line 1 x\lower2ex\hbox{xxx}\par +line 2 x\raise2ex\hbox{xxx}\par +line 3 \par +\stopbuffer + +\startbuffer[fake-3] +\hsize 2cm \dontleavehmode +x\lower2ex\hbox{xxx} line 1 \par +line 2 x\raise2ex\hbox{xxx}\par +line 3 \par +\stopbuffer + +\startplacefigure[reference=fig:profiling:simple-text,title={Variants of profiling, using a constructed two-line text.}] + \switchtobodyfont[10pt] + \enabletrackers[profiling.show] + \startcombination[nx=1,ny=3] + \startcontent + \startcombination[nx=5,ny=1,distance=10mm,style=\tt] + {\showboxes\profiledbox[none] [distance=0pt]{\getbuffer[fake-1]}} {none} + {\showboxes\profiledbox[strict][distance=0pt]{\getbuffer[fake-1]}} {strict/0pt} + {\showboxes\profiledbox[strict][distance=1pt]{\getbuffer[fake-1]}} {strict/1pt} + {\showboxes\profiledbox[fixed] [distance=0pt]{\getbuffer[fake-1]}} {fixed/0pt} + {\showboxes\profiledbox[fixed] [distance=1pt]{\getbuffer[fake-1]}} {fixed/1pt} + \stopcombination + \stopcontent + \startcaption + no excessive height and depth + \stopcaption + \startcontent + \startcombination[nx=5,ny=1,distance=10mm,style=\tt] + {\showboxes\profiledbox[none] [distance=0pt]{\getbuffer[fake-2]}} {none} + {\showboxes\profiledbox[strict][distance=0pt]{\getbuffer[fake-2]}} {strict/0pt} + {\showboxes\profiledbox[strict][distance=1pt]{\getbuffer[fake-2]}} {strict/1pt} + {\showboxes\profiledbox[fixed] [distance=0pt]{\getbuffer[fake-2]}} {fixed/0pt} + {\showboxes\profiledbox[fixed] [distance=1pt]{\getbuffer[fake-2]}} {fixed/1pt} + \stopcombination + \stopcontent + \startcaption + some excessive height and depth (overlapping) + \stopcaption + \startcontent + \startcombination[nx=5,ny=1,distance=10mm,style=\tt] + {\showboxes\profiledbox[none] [distance=0pt]{\getbuffer[fake-3]}} {none} + {\showboxes\profiledbox[strict][distance=0pt]{\getbuffer[fake-3]}} {strict/0pt} + {\showboxes\profiledbox[strict][distance=1pt]{\getbuffer[fake-3]}} {strict/1pt} + {\showboxes\profiledbox[fixed] [distance=0pt]{\getbuffer[fake-3]}} {fixed/0pt} + {\showboxes\profiledbox[fixed] [distance=1pt]{\getbuffer[fake-3]}} {fixed/1pt} + \stopcombination + \stopcontent + \startcaption + some excessive height and depth (out of touch) + \stopcaption + \stopcombination + \disabletrackers[profiling.show] +\stopplacefigure + +\in {Figure} [fig:profiling:simple-text] we show what happens when we add some +more excessive height and depth to lines. The samples are: + +\starttyping +line 1 x\lower2ex\hbox{xxx}\par +line 2 x\raise2ex\hbox{xxx}\par +line 3 \par +\stoptyping + +and: + +\starttyping +x\lower2ex\hbox{xxx} line 1 \par +line 2 x\raise2ex\hbox{xxx}\par +line 3 \par +\stoptyping + +Here the \type {strict} variant has some effect while \type {fixed} only has some +influence on the height and depth of lines. Later we will see that \type {fixed} +operates in steps and the default step is large so here we never meet the +criteria for closing up. \footnote {In \CONTEXT\ we normally use \type {\high} +and \type {\low} and both ensure that we don't exceed the natural height and +depth.} + +A profiled box is typeset with \type {\profiledbox}. There is some control +possible but the options are not yet set in stone so we won't use them all here. +Profiling can be turned on for the whole document with \type {\setprofile} but +I'm sure that will seldom happen, and these examples show why: one cannot +beforehand say if the result looks good. Let's now apply profiling to a real +text. If you play with this yourself you can show profiles in gray with a +tracker: + +\starttyping +\enabletrackers[profiling.show] +\stoptyping + +\newbox\myprofiledbox + +\startbuffer[raw-1] +\profiledbox + [strict] + [distance=0pt] + {\nl\getbuffer[example-1]} +\stopbuffer + +\startbuffer[raw-2] +\profiledbox + [strict] + [distance=1pt] + {\nl\getbuffer[example-1]} +\stopbuffer + +\startbuffer[raw-3] +\profiledbox + [strict] + [height=2\strutht, + depth=2\strutdp, + distance=1pt] + {\nl\getbuffer[example-1]} +\stopbuffer + +\startplacefigure[reference=fig:profiling:distances,title={Examples width different dimensions.}] + \enabletrackers[profiling.show] + \startcombination[nx=1,ny=3] + \startcontent + \setbox\myprofiledbox\rawbuffer{raw-1} + \xdef\LastProfiledHeight{\the\htdp\myprofiledbox} + \box\myprofiledbox + \stopcontent + \startcaption + zero distance, resulting height \LastProfiledHeight + \stopcaption + \startcontent + \setbox\myprofiledbox\rawbuffer{raw-2} + \xdef\LastProfiledHeight{\the\htdp\myprofiledbox} + \box\myprofiledbox + \stopcontent + \startcaption + distance, resulting height \LastProfiledHeight + \stopcaption + \startcontent + \setbox\myprofiledbox\rawbuffer{raw-3} + \xdef\LastProfiledHeight{\the\htdp\myprofiledbox} + \box\myprofiledbox + \stopcontent + \startcaption + distance, double height and depth, resulting height \LastProfiledHeight + \stopcaption + \stopcombination + \disabletrackers[profiling.show] +\stopplacefigure + +We show the effects of setting distances in \in {figure} +[fig:profiling:distances]. We start with a zero distance: + +\typebuffer[raw-1] + +Because we don't want lines to touch we then set the minimum distance to a +reasonable value (1pt). + +\typebuffer[raw-2] + +Finally we also double the height and depth of lines, something that normally will +not be done. The defaults are the standard height and depth (the ones you get +when you inject a so-called \type{\strut}). + +\typebuffer[raw-3] + +The problem with this kind of analysis is that deciding when and how to use this +information to improve spacing is non|-|trivial. One of the characteristics of +user demand is that it nearly always concerns rather specific situations and that +suggested solutions could work only in those cases. But as soon as we have one +exceptional situation, intervention is needed which in turn means that a +mechanism has to be under complete user control. That itself assumes that the +user still has control, which is not the case in automated workflows. In fact, as +soon as one is in control over the source and rendering, there are often easier +ways to deal with the few cases that need treatment. Possible interference can +come from, for instance: + +\startitemize[packed] +\startitem whitespace between paragraphs \stopitem +\startitem section titles (using different fonts and spacing) \stopitem +\startitem descriptions and other intermezzos \stopitem +\startitem images that interrupt the flow, or end up next to text \stopitem +\startitem ornaments like margin words (we catch some) \stopitem +\startitem text backgrounds making spacing assumptions \stopitem +\stopitemize + +After a few decades of using \TEX\ and writing solutions, it has become pretty +clear that fully automated typesetting is a dream, if only because the input can +be pretty weird and inconsistent and demands (from those who are accustomed to +tweaking manually in a desktop publishing application) can be pretty weird and +inconsistent too. So, the only real solution is to use some kind of artificial +intelligence that one can feed with demands and constraints and that hopefully is +clever enough to deal with the inconsistencies. As this kind of computing is +unlikely to happen in my lifetime, poor man explicit solutions have to do the job +for now. One can add all kinds of heuristics to the profiler but this can +backfire when control is needed. Alternatively one can end up with many options +like we have in grid snapping. + +\stopsection + +\startsection[title=Where to use profiling] + +In \CONTEXT\ there are four places (maybe a few more eventually) where this kind +of control over spacing makes sense: + +\startitemize[packed] +\startitem the main text flow in single column mode \stopitem +\startitem multi|-|column mode, especially mixed columns \stopitem +\startitem framed texts, used for all kinds of content \stopitem +\startitem explicitly (balanced) split boxes \stopitem +\stopitemize + +Because framed texts are used all over, for instance in tables, it means that if +we provide control over spacing using profiles, many \CONTEXT\ mechanisms can use +it. However, enabling this for all packaging has a significant overhead so it has +to be used with care so that there is no performance hit when it is not used. +Here is an easy example using \type {\framed}: + +\starttyping +\framed + [align=normal, + profile=fixed, + frame=off] + {some text ...} +\stoptyping + +For the following examples we define this helper: + +\startbuffer +\starttexdefinition demo-profile-1 #1 + \framed + [align=normal,profile=#1] + {xxx$\frac{1}{\frac{1}{\frac{1}{2}}}$ + \par + $\frac{\frac{1}{\frac{1}{2}}}{2}$xxx} +\stoptexdefinition +\stopbuffer + +\typebuffer \getbuffer + +We apply this to predefined profiles. The macro is called like this: + +\starttyping +\texdefinition{demo-profile-1}{fixed} +\stoptyping + +\starttexdefinition unexpanded ProfileSteps #1 + \startcombination[nx=5,ny=1] + {#1\hbox to 6em{\hss\texdefinition{demo-profile-1} {}\hss}} {\small vbox} + {#1\hbox to 6em{\hss\texdefinition{demo-profile-1} {fixed}\hss}} {\small\type{fixed}} + {#1\hbox to 6em{\hss\texdefinition{demo-profile-1} {halffixed}\hss}} {\small\type{halffixed}} + {#1\hbox to 6em{\hss\texdefinition{demo-profile-1}{quarterfixed}\hss}} {\small\type{quarterfixed}} + {#1\hbox to 6em{\hss\texdefinition{demo-profile-1} {eightsfixed}\hss}} {\small\type{eightsfixed}} + \stopcombination +\stoptexdefinition + +The outcome can depend on the font used: in \in {figure} +[fig:profiling:profiles-fonts] we show Latin Modern, \TEX\ Gyre Pagella and +Dejavu. Because in \CONTEXT\ the line height depends on the bodyfont; each case +is different. + +\startplacefigure[reference=fig:profiling:profiles-fonts,title=A few fonts compared.] + \enabletrackers[profiling.show] + \startcombination[nx=1,ny=3] + \startcontent + \ProfileSteps{\switchtobodyfont[modern]} + \stopcontent + \startcaption + Latin Modern + \stopcaption + \startcontent + \ProfileSteps{\switchtobodyfont[pagella]} + \stopcontent + \startcaption + Pagella + \stopcaption + \startcontent + \ProfileSteps{\switchtobodyfont[dejavu]} + \stopcontent + \startcaption + Dejavu + \stopcaption + \stopcombination + \disabletrackers[profiling.show] +\stopplacefigure + +\startplacefigure[reference=fig:profiling:profiles-boxedcolumns,title={Boxed columns without profile.}] + \enabletrackers[profiling.show] + \startcombination[nx=1,ny=3] + \startcontent + \startboxedcolumns[distance=2.2em,grid=yes,profile=none,frame=on] + \nl\getbuffer[example-1] + \stopboxedcolumns + \stopcontent + \startcaption + none on grid + \stopcaption + \startcontent + \startboxedcolumns[distance=2.2em,grid=yes,profile=strict,frame=on] + \nl\getbuffer[example-1] + \stopboxedcolumns + \stopcontent + \startcaption + strict on grid + \stopcaption + \startcontent + \startboxedcolumns[distance=2.2em,grid=yes,profile=fixed,frame=on] + \nl\getbuffer[example-1] + \stopboxedcolumns + \stopcontent + \startcaption + fixed on grid + \stopcaption + \stopcombination + \disabletrackers[profiling.show] +\stopplacefigure + +As mentioned, we need this kind of profiling in multi|-|column typesetting, so +let us have a look at that now. Columns are processed in grid mode but this is +taken into account. We can simulate this by using boxed columns; see \in {figure} +[fig:profiling:profiles-boxedcolumns]. One of the biggest problems is what to do +with the bottom and top of a page or column. This will probably take a bit more +to get right, and likely we will end up with different strategies. We can also +think of special handlers but that will come with a high speed penalty. In the +\type {strict} variant we don't mess with the dimension of a line too much, but +the \type {fixed} alternative will get some more control. + +Although using this feature looks promising it is also dangerous. For instance a +side effect can be that interline spacing becomes inconsistent and even ugly. It +really depends on the content. Also, as soon as some grid snapping is used, the +gain becomes less, simply because the solution space is smaller. Then of course +there is the matter of overall look and feel: most documents that need this kind +of magic look bad anyway, so why bother. In this respect it is comparable to +applying protrusion and expansion. There are hardly any combinations of design +and content where micro|-|typography makes sense to use: in prose perhaps, but +not in mixed content. On the other hand, profiling makes more sense in mixed +content than in prose. + +Not everything that is possible should be used. In \in {figure} +[fig:profiling:fake-examples-1] we show some fake paragraphs with profiles +applied, the first series (random range~2) has a few excessive snippets, the last +one (random range~5) has many. In \in {figure} [fig:profiling:fake-examples-2] we +show them in a different arrangement. Although there are differences it is hard +to say if the results look better. We scaled down the results and used gray fake +blurs instead of real text in order to get a better impression of the so-called +(overall) grayness of a text. + +% \starttexdefinition profile-sample-set #1#2#3 +% \startuseMPgraphic{random-thing} +% if round(uniformdeviate(10)) = 5 : +% fill unitsquare enlarged ((1mm,#2mm) randomized(1mm,#1mm)) withcolor \MPcolor{#3} ; +% else : +% fill unitsquare enlarged ((1mm,1mm) randomized(1mm,1mm)) withcolor \MPcolor{darkgray} ; +% fi ; +% draw origin withpen pencircle scaled 1mm ; +% \stopuseMPgraphic +% \setbox#1\hbox\bgroup +% \dorecurse {500} {% +% \dontleavehmode +% \bgroup +% \obeyMPboxdepth +% \useMPgraphic{random-thing}% +% \egroup +% \hskip 3mm plus 3mm minus 1mm\relax +% }% +% \egroup +% \stoptexdefinition + +% \starttexdefinition profile-sample-get #1#2 +% \scale +% [width=\dimexpr(\textwidth-2em)/4\relax] +% {\framed +% [offset=overlay,align=normal,profile=#2] +% {\unhcopy#1}} +% \stoptexdefinition + +% \texdefinition{profile-sample-set}{0}{2}{darkred} +% \texdefinition{profile-sample-set}{2}{3}{darkgreen} +% \texdefinition{profile-sample-set}{4}{4}{darkblue} +% \texdefinition{profile-sample-set}{6}{5}{darkyellow} + +\startMPdefinitions + color FakeRed ; FakeRed := \MPcolor{darkred} ; + color FakeGreen ; FakeGreen := \MPcolor{darkgreen} ; + color FakeBlue ; FakeBlue := \MPcolor{darkblue} ; + color FakeYellow ; FakeYellow := \MPcolor{darkyellow} ; + color FakeGray ; FakeGray := \MPcolor{darkgray} ; + def FakeInColor(expr h,c) = + if round(uniformdeviate(10)) = 5 : + fill unitsquare enlarged ((1mm,h*mm) randomized(1mm,h*mm)) withcolor c ; + else : + fill unitsquare enlarged ((1mm,1 mm) randomized(1mm,1 mm)) withcolor FakeGray ; + fi ; + draw origin withpen pencircle scaled 1mm ; + enddef ; +\stopMPdefinitions + +\starttexdefinition profile-sample-set #1#2#3 + \setbox#1\hbox\bgroup + \dorecurse {500} {% + \dontleavehmode + \bgroup + \obeyMPboxdepth + \startMPcode FakeInColor(#2,#3)\stopMPcode + \egroup + \hskip 3mm plus 3mm minus 1mm\relax + }% + \egroup +\stoptexdefinition + +\starttexdefinition profile-sample-get #1#2 + \scale + [width=\dimexpr(\textwidth-2em)/4\relax] + {\framed + [offset=overlay,align=normal,profile=#2] + {\unhcopy#1}} +\stoptexdefinition + +\texdefinition{profile-sample-set}{0}{2}{FakeRed} +\texdefinition{profile-sample-set}{2}{3}{FakeGreen} +\texdefinition{profile-sample-set}{4}{4}{FakeBlue} +\texdefinition{profile-sample-set}{6}{5}{FakeYellow} + +\startplacefigure + [reference=fig:profiling:fake-examples-1, + title={Some examples, each row has progressively more excessive snippets.}] + \startcombination[location=top,nx=4,ny=4] + {\texdefinition{profile-sample-get}{0}{none}} {\tttf none / 2} + {\texdefinition{profile-sample-get}{0}{strict}} {\tttf strict / 2} + {\texdefinition{profile-sample-get}{0}{fixed}} {\tttf fixed / 2} + {\texdefinition{profile-sample-get}{0}{halffixed}} {\tttf halffixed / 2} + {\texdefinition{profile-sample-get}{2}{none}} {\tttf none / 3} + {\texdefinition{profile-sample-get}{2}{strict}} {\tttf strict / 3} + {\texdefinition{profile-sample-get}{2}{fixed}} {\tttf fixed / 3} + {\texdefinition{profile-sample-get}{2}{halffixed}} {\tttf halffixed / 3} + {\texdefinition{profile-sample-get}{4}{none}} {\tttf none / 4} + {\texdefinition{profile-sample-get}{4}{strict}} {\tttf strict / 4} + {\texdefinition{profile-sample-get}{4}{fixed}} {\tttf fixed / 4} + {\texdefinition{profile-sample-get}{4}{halffixed}} {\tttf halffixed / 4} + {\texdefinition{profile-sample-get}{6}{none}} {\tttf none / 5} + {\texdefinition{profile-sample-get}{6}{strict}} {\tttf strict / 5} + {\texdefinition{profile-sample-get}{6}{fixed}} {\tttf fixed / 5} + {\texdefinition{profile-sample-get}{6}{halffixed}} {\tttf halffixed / 5} + \stopcombination +\stopplacefigure + +\startplacefigure + [reference=fig:profiling:fake-examples-2, + title={The same examples, rearranged such that each row has a different profiling variant.}] + \startcombination[location=top,nx=4,ny=4] + {\texdefinition{profile-sample-get}{0}{none}} {\tttf none / 2} + {\texdefinition{profile-sample-get}{2}{none}} {\tttf none / 3} + {\texdefinition{profile-sample-get}{4}{none}} {\tttf none / 4} + {\texdefinition{profile-sample-get}{6}{none}} {\tttf none / 5} + {\texdefinition{profile-sample-get}{0}{strict}} {\tttf strict / 2} + {\texdefinition{profile-sample-get}{2}{strict}} {\tttf strict / 3} + {\texdefinition{profile-sample-get}{4}{strict}} {\tttf strict / 4} + {\texdefinition{profile-sample-get}{6}{strict}} {\tttf strict / 5} + {\texdefinition{profile-sample-get}{0}{fixed}} {\tttf fixed / 2} + {\texdefinition{profile-sample-get}{2}{fixed}} {\tttf fixed / 3} + {\texdefinition{profile-sample-get}{4}{fixed}} {\tttf fixed / 4} + {\texdefinition{profile-sample-get}{6}{fixed}} {\tttf fixed / 5} + {\texdefinition{profile-sample-get}{0}{halffixed}} {\tttf halffixed / 2} + {\texdefinition{profile-sample-get}{2}{halffixed}} {\tttf halffixed / 3} + {\texdefinition{profile-sample-get}{4}{halffixed}} {\tttf halffixed / 4} + {\texdefinition{profile-sample-get}{6}{halffixed}} {\tttf halffixed / 5} + \stopcombination +\stopplacefigure + +\stopsection + +\startsection[title=Conclusion] + +Although profiling seems interesting, in practice it does not have much value in +an automated flow. Ultimately, in the project for which I investigated this +trickery, only in the final stage was some last minute optimization of the +rendering done. We did that by injecting directives. Think of page breaks that +make the result look more balanced. Optimizing image placement happens in an +earlier stage because the text can refer to images like \quotation {in the +picture on the left, we see \unknown}. Controlling profiles is much harder. In +fact, the more clever we are, the harder it gets to beat it when we want an +exception. All these mechanisms: spacing, snapping, profiling, breaking pages, +image placement, to mention a few, have to work together. For projects that +depend on such placement, it might be better to write dedicated mechanisms than +to try to fight with clever built|-|in features. + +In practice, probably only the \type {fixed} alternative makes sense and as that +one has a boundary condition similar to (or equal, depending on other settings) +snapping on gridsteps, the end result might not be that different from doing +nothing. In \in {figure} [fig:profiling:fake-examples-3] you see that the vbox +variant is not that bad. And extremely difficult content is unlikely to ever look +perfect unless some manual intervention happens. Therefore, from the perspective +of \quotation {fine points of text typesetting} some local (manual) control might +be more interesting and relevant. + +\texdefinition{profile-sample-set}{0}{3}{FakeGreen} +\texdefinition{profile-sample-set}{2}{3}{FakeGreen} +\texdefinition{profile-sample-set}{4}{3}{FakeGreen} + +In the end, I didn't need this profiling feature at all: because there are +expectations with respect to how many pages a book should have, typesetting in +columns was not needed. It didn't save that many pages, and the result would +never look that much better, simply because of the type of content. Large images +were also spoiling the game. Nevertheless we will keep profiles in the core and +it might even get extended. One question remains: at what point do we stop adding +such features? The answer would be easier if \TEX\ wasn't so flexible. + +\startplacefigure[location=top,reference=fig:profiling:fake-examples-3,title=Three similar random cases.] + \startcombination[location=top,nx=3,ny=3] + {\texdefinition{profile-sample-get}{0}{}} {\tttf vbox 1} + {\texdefinition{profile-sample-get}{0}{strict}} {\tttf strict 1} + {\texdefinition{profile-sample-get}{0}{fixed}} {\tttf fixed 1} + {\texdefinition{profile-sample-get}{2}{}} {\tttf vbox 2} + {\texdefinition{profile-sample-get}{2}{strict}} {\tttf strict 2} + {\texdefinition{profile-sample-get}{2}{fixed}} {\tttf fixed 2} + {\texdefinition{profile-sample-get}{4}{}} {\tttf vbox 3} + {\texdefinition{profile-sample-get}{4}{strict}} {\tttf strict 3} + {\texdefinition{profile-sample-get}{4}{fixed}} {\tttf fixed 3} + \stopcombination +\stopplacefigure + +\stopsection + +\stopchapter + +\page \enabledirectives[visualizers.fraction=default] + +\stopcomponent + |