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   8 <!====================================================================>
   9
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  13 <p>
  14
  15 <a name="TOP"></a>
  16 <a name="TYPESETTING">
  17         <h1 align="center"><u>USING TYPESETTING MACROS DURING DOCUMENT PROCESSING</u></h1>
  18 </a>
  19
  20 During document processing, most of the
  21 <a href="typesetting.html#MACROS_TYPESETTING">typesetting macros</a>
  22 affect type in the document globally.  For example, if you turn kerning
  23 off, pairwise kerning is disabled not only in paragraphs, but
  24 also in headers, footers, quotes, and so on.
  25 <p>
  26 Typesetting macros that alter margins and line lengths affect
  27 <a href="definitions.html#TERMS_RUNNING">running text</a>
  28 globally (or at least try to), but leave headers/footers and footnotes
  29 alone.  (To indent footnotes, see the full explanation of the
  30 <a href="docelement.html#FOOTNOTE">FOOTNOTE</a>
  31 macro.)
  32 <p>
  33 <strong>Mom</strong>'s tabs
  34 (both
  35 <a href="typesetting.html#TYPESETTING_TABS">typesetting tabs</a>
  36 and
  37 <a href="typesetting.html#STRING_TABS">string tabs</a>)
  38 behave as expected in running text during document processing.  Tab
  39 structures that do not exceed the line length of running text are
  40 preserved sensibly from page to page, and, if
  41 <a href="docprocessing.html#COLUMNS">COLUMNS</a>
  42 are enabled, from column to column.
  43 <p>
  44 Some typesetting macros, however, when used during document
  45 processing, behave in special ways.  These are the macros that deal
  46 with the basic parameters of type style: horizontal and vertical
  47 margins, line length,
  48 <a href="definitions.html#TERMS_FAMILY">family</a>,
  49 <a href="definitions.html#TERMS_FONT">font</a>,
  50 <a href="definitions.html#TERMS_PS">point size</a>,
  51 <a href="definitions.html#TERMS_LEADING">leading</a>,
  52 and
  53 <a href="definitions.html#TERMS_QUAD">quad</a>.
  54 <p>
  55 <strong>NOTE:</strong> See the section on
  56 <a href="#TB_MARGINS">Top and bottom margins in document processing</a>
  57 for information on how <strong>mom</strong> interprets
  58 <a href="typesetting.html#T_MARGIN">T_MARGIN</a>
  59 and
  60 <a href="typesetting.html#B_MARGIN">B_MARGIN</a>
  61 in document processing.
  62
  63 <p>
  64 <strong>Mom</strong> assumes that any changes to these parameters
  65 stem from a temporary need to set type in a style different from that
  66 provided by <strong>mom</strong>'s
  67 <a href="docelement.html#INDEX_DOCELEMENT">document element tags</a>.
  68 In other words, you need to do a bit of creative typesetting in the
  69 middle of a document.
  70 <p>
  71 The following lists those typesetting macros whose behaviour during
  72 document processing requires some explanation.
  73 <p>
  74 <pre>
  75 MACRO           EFFECT DURING DOCUMENT PROCESSING
  76 -----           ---------------------------------
  77
  78 L_MARGIN        *The left margin of all running text
  79                  assumes the new value.
  80
  81                 *The line length remains unaltered.
  82
  83                 *The header and footer left margin
  84                  remain at the current document default.
  85
  86                 (You won't use this often by itself.  Most
  87                  likely, you'll use it in combination with
  88                  R_MARGIN or LL.)
  89
  90 R_MARGIN        *The right margin of all running text
  91                  assumes the new value.  In other words,
  92                  the line length is altered.
  93
  94                 *The header and footer right margin
  95                  remain at the current document default.
  96
  97 LL              *The line length of all running text
  98                  is set to the new value.
  99
 100                 *The header and footer line length remain
 101                  at the current document default.
 102
 103 FAMILY          *Changes family for the duration of the
 104                  current tag only.  As soon as another document
 105                  element tag is invoked, the family reverts to
 106                  the current default for the new tag.
 107
 108 FT              *Changes font for the duration of the
 109                  current tag only.  As soon as another document
 110                  element tag is entered, the font reverts
 111                  to the current default for the new tag.
 112
 113                  N.B. -- \*[SLANT] and \*[BOLDER] affect
 114                  paragraph text, and remain in effect for all
 115                  paragraphs until turned off.  If you want to
 116                  use them in a macro that takes a string
 117                  argument, include the escape in the string.
 118                  \*[COND] and \*[EXT] behave similarly.
 119
 120 PT_SIZE         *Changes point size for the duration of the
 121                  current tag only.  As soon as another document
 122                  element tag is entered, the point size reverts
 123                  to the current document default for the new
 124                  tag.
 125
 126 LS              *Changes line space for the duration of the
 127                  current tag only.  As soon as another document
 128                  element tag is entered, the line space reverts to
 129                  the current document default for the new
 130                  tag.
 131
 132                  Using LS to temporarily change leading within a
 133                  document will almost certainly result in a bottom
 134                  margin that doesn't align with the bottom margin
 135                  of subsequent pages.  You'll need to use the SHIM
 136                  macro to get mom back on track when you're ready
 137                  to return to the document's default leading.
 138
 139 QUAD            *Changes quad for the duration of the
 140                  current tag only.  As soon as another document
 141                  element tag is entered, the quad reverts to
 142                  the current document default for the new
 143                  tag.
 144
 145                  N.B. -- Line-for-line quadding macros
 146                  (LEFT, CENTER, RIGHT) are also temporary,
 147                  overridden by the QUAD value of any subsequent
 148                  document element tag.
 149 </pre>
 150 <hr>
 151
 152 <!=====================================================================>
 153
 154 <a name="TB_MARGINS">
 155         <h2><u>Top and bottom margins in document processing</u></h2>
 156 </a>
 157
 158 Normally, <strong>mom</strong> establishes the top and bottom margins
 159 of
 160 <a href="definitions.html#TERMS_RUNNING">running text</a>
 161 in documents from the values of <strong>HEADER_MARGIN +
 162 HEADER_GAP</strong> and <strong>FOOTER_MARGIN + FOOTER_GAP</strong>
 163 respectively.  However, if you invoke
 164 <a href="typesetting.html#T_MARGIN">T_MARGIN</a>
 165 or
 166 <a href="typesetting.html#B_MARGIN">B_MARGIN</a>
 167 either before or after
 168 <a href="docelement.html#START">START</a>,
 169 they set the top and bottom margins of running text irrespective
 170 of <strong>HEADER_GAP</strong> and <strong>FOOTER_GAP</strong>.
 171 <p>
 172 Put another way, in document processing, <strong>T_MARGIN</strong>
 173 and <strong>B_MARGIN</strong> set the top and bottom margins of
 174 running text, but have no effect on the placement of
 175 <a href="definitions.html#TERMS_HEADER">headers</a>,
 176 <a href="definitions.html#TERMS_FOOTER">footers</a>,
 177 or page numbers.
 178
 179 <p>
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