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diff --git a/doc/user/typ_plai b/doc/user/typ_plai new file mode 100644 index 0000000..a880ccb --- /dev/null +++ b/doc/user/typ_plai @@ -0,0 +1,76 @@ +@Section + @Title { Plain text documents } + @Tag { plain } +@Begin +@PP +Occasionally you may need to produce an output file containing plain text +plain.text. @Index { plain text documents } +rather than PostScript, for example for an online manual entry or to send +as electronic mail. Any document that can be produced by Lout in +PostScript can be produced in plain text as well, by adding a @Code "-p" +flag to the Unix command line: +@ID @Code "lout -p simple" +No other changes are required. Here we are sending the output directly to +the screen, but it can be redirected to a file, or piped through the +@Code more command for viewing one page at a time, etc. +@PP +Of course, plain text is an extremely limited medium of communication +compared with PostScript, and this forces Lout to make some rather +drastic compromises: +@BulletList gap { @ParaGap } +@LI { Symbols like {@Code "@Bullet"}, which stand for unusual characters, +produce printable characters which approximate the PostScript ones. For +example, {@Code "@Bullet"} produces {@Code "o"}. However, the @Code "@Char" +and @Code "@Sym" symbols often produce unprintable characters, and are best +avoided; } +@LI { All font and size changes are ignored, since plain text has only +one font and size. Every character is taken to be @Eq { 1 frac 10 } inch +wide and @Eq { 1 frac 6 } inch high; } +@LI { No underlines are printed; } +@LI { No margin notes are printed; } +@LI { Scaled objects are not printed unless the scale factor happens to be 1; } +@LI { Rotated objects are not printed unless the angle happens to be zero +degrees. This means that page orientations (Section {@NumberOf pagesize}) +other than @Code Portrait do not work; } +@LI { Ruled lines are not printed, and paint and colour options are +ignored. This spoils the graphics and graphs of Chapters +{@NumberOf graphics}, {@NumberOf diagrams}, and {@NumberOf graphs}. } +@EndList +Despite the problems, many things work surprisingly well. Tables, for example, +look very good. It does no harm to try things and see if they work out. +@PP +The worst problem with plain text is that characters cannot be placed at +arbitrary points on the page. A superscript, for example, is impossible to +place correctly, so Lout uses a different layout for footnote labels (and +makes a mess of equations, which are best avoided). Because of this problem +it's best to make all horizontal lengths multiples of @Eq {1 frac 10} inch +(conveniently expressed as {@Code 1s}), and all vertical lengths multiples +of @Eq { 1 frac 6 } inch (conveniently expressed as {@Code 1f}). To help +you do this, the setup files contain many entries that look like this +example: +@ID @Code "# @InitialBreak { {adjust 1.2fx hyphen} @OrIfPlain {ragged 1fx nohyphen} }" +The meaning is that the value of @Code "@InitialBreak" will be +@Code "adjust 1.2fx hyphen" usually, but will switch to +{@Code "ragged 1fx nohyphen"}, which is better suited to plain text, +if the @Code "-p" command line flag is used. These setup file values +allow you to switch from PostScript to plain text and back again without +changing anything at all except the @Code "-p" command line flag. +@PP +If you use @Code "lout -P" instead of {@Code "lout -p"}, the plain text +output will contain a form-feed character (control-L) after each page +form.feed @Index { form-feed in plain text } +except the last. This character causes most printing devices to start +a new page, which is very useful when your page height is not exactly +right. +@PP +The @Code "@Document" symbol (Section {@NumberOf ordinary}) has an +unpaginated. @Index @Code "@Unpaginated" +@Code "@Unpaginated" option which, when set to {@Code "Yes"}, causes +the plain text output to appear unpaginated, that is, in one long +continous stream with no page breaks. Its value is ignored if plain text +output is not in effect, so it can be safely set to @Code "Yes" in +documents intended for formatting both ways. The usual margins apply; +footnotes appear at the end; figures and tables do not work. Lout +stupidly reads the entire document before producing any output when +this option is used, so if the document is long you might run out of memory. +@End @Section |