summaryrefslogtreecommitdiff
path: root/macros/luatex/latex/novel/lualatex/novel-CalculateLayout.sty
blob: a9d993b6b7555922480f6aaacc00368218d6ec54 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
%%
%% This is file `novel-CalculateLayout.sty', part of `novel' document class.
%% Copyright 2017-2023 Robert Allgeyer.
%% 
%% It may be distributed and/or modified under the
%% conditions of the LaTeX Project Public License, either version 1.3c
%% of this license or (at your option) any later version.
%% The latest version of this license is in
%%    http://www.latex-project.org/lppl.txt
%% and version 1.3c or later is part of all distributions of LaTeX
%% version 2005/12/01 or later.
%% 
%%
\ProvidesFile{novel-CalculateLayout.sty}%
[2023/03/25 v1.81a LaTeX file (layout calculations)]
%%

%%
%% This file is loaded \AtEndPreamble, which precedes \AtBeginDocument.
%%



%% PROVIDE DEFAULT TRIM SIZE, MARGINS, AND NORMAL EM SIZE, IF NOT SET BY USER
%% ----------------------------------------------------------------------------
% Default Trim Size is 5.5in W x 8.5in H, unless \SetTrimSize used.
% This size is typical of American P.O.D. softcover fiction:
\if@SetTrimSize\else
  \gsetlength\@TrimWidth{5.5in}
  \gsetlength\@TrimHeight{8.5in}
\fi
% Default margins based on Trim Height, unless \SetMargins used:
\if@SetMargins\else
  \ifdimcomp{\@TrimHeight}{<}{8.99in}{ % small sizes:
    \gsetlength\@TopMargin{0.5in}
    \gsetlength\@OuterMargin{0.5in}
    \gsetlength\@BottomMargin{0.5in}
    \gsetlength\@InnerMargin{0.75in}
  }{ % medium sizes:
    \ifdimcomp{\@TrimHeight}{<}{9.99in}{ %
      \gsetlength\@TopMargin{0.75in}
      \gsetlength\@OuterMargin{0.75in}
      \gsetlength\@BottomMargin{0.75in}
      \gsetlength\@InnerMargin{1in}
    }{ % large sizes:
      \gsetlength\@TopMargin{1in}
      \gsetlength\@OuterMargin{1in}
      \gsetlength\@BottomMargin{1in}
      \gsetlength\@InnerMargin{1.25in}
    } %
  } %
\fi
% Default normal em size is based on Trim Width:
\if@FontSizeSet\else
  \ifdimcomp{\@TrimWidth}{<}{5.49in}{
    \gsetlength\@SetFontSize{11pt} % smaller books
  }{
    \ifdimcomp{\@TrimWidth}{<}{6.24in}{
      \gsetlength\@SetFontSize{11.4pt} % medium books
    }{
      \gsetlength\@SetFontSize{12pt} % larger books
    } %
  } %
\fi
%% end set default trim, margins, normal em size.


%% THEORY OF PAGE LAYOUT
%% ----------------------------------------------------------------------------
% The "available width" is the trim width minus the outer and inner margins:
\newlength\@AvailableWidth
\gsetlength\@AvailableWidth{\@TrimWidth-\@OuterMargin-\@InnerMargin}
% The "occupied width" of the text block is the TeX dimension \textwidth.
%   Your originally set layout can always fill the available width.
\gsetlength\textwidth{\@AvailableWidth}
% The "available height" is the trim height minus the top and bottom margins:
\newlength\@AvailableHeight
\gsetlength\@AvailableHeight{\@TrimHeight-\@TopMargin-\@BottomMargin}
% The "occupied height" includes header, textblock, footer, and allowances
%   for risers/diacriticals at top, descenders at bottom. It must fit within
%   the available height. This is the tricky part, so pay attention:
% In `novel' class, the topmost line of text (main block or header)
%   is positioned with its baseline at 1 normal em below available top.
%   That provides good clearance for uppercase letters with diacritical marks.
% The lowermost line of text (main block or footer) is positioned with its
%   baseline at 0.3 normal em above available bottom. This provides
%   good clearance for descenders.
% So, if your text does not have uppercase diacriticals, or if you use
%   a footer with lining numbers (no descenders), then the upper/lower margins
%   will appear to be a little larger than you set them.
% The headjump includes the line itself, plus any added gap to the main text.
%   An unused jump is re-set to 0:
\if@HasHeader\else\gdef\@HeadJump{0}\fi
%%
% TeX assumes that your layout has a footer, even if you do not want one.
%   Novel handles this by setting the baseline of the mandatory footer at
%   1 normal baselineskip below the last line of main text. Then, one line is
%   subtracted from the occupied line count. That places the empty, unused
%   virtual footer in the lower margin, where it does not matter. When you
%   do have a footer, the necessary line space is added, and the content
%   is positioned from the virtual footer using \smash and \raisebox.
%   Yes, it is complicated, but it handles more layout possibilities.
%   The \@FootJumpFix is one less than \@FootJump, or -1 when no footer:
\if@HasFooter
  \FPsub\@FootJumpFix{\@FootJump}{1}
\else
  \gdef\@FootJumpFix{-1}
\fi
% Putting it all together, the "occupied height" is:
%   1.3\@SetFontSize + (\@HeadJump+\@LinesPerPage+\@FootJumpFix)\baselineskip
%
%% end theory of page layout.


%% SET DEFAULT LINES PER PAGE, IF NOT SET BY USER
%% ----------------------------------------------------------------------------
% Lines per page refers only to the main text block, not header/footer:
\if@LinesPerPage\else
  % Estimate \baselineskip as 1.3\@SetFontSize, which is a comfortable value.
  % Calculate resulting \@LinesPerPage, then proceed as if set.
  % Actual \baselineskip will be re-calculated later.
  \edef\@tempLPP{%
    \fpeval{% package xfp
      (\@AvailableHeight - 0.3\@SetFontSize) % adjusts for final descenders
      / (1.3*\@SetFontSize) % denominator, with desired skip/em ratio
      -\@HeadJump -\@FootJumpFix % adjustments
    }%
  } %
  \FPtrunc{\@LinesPerPage}{\@tempLPP}{0} % final, integer floor
\fi
% Error if too few lines per page, whether set or default:
\FPiflt{\@LinesPerPage}{2}
  \ClassError{novel}{Calculated LinesPerPage less than 2}%
   {Too few lines. Either font size too big, or text height too small.}%
\fi
%% end set default lines per page.


%% CALCULATE BASELINESKIP
%% ----------------------------------------------------------------------------
% In `novel' class, the user does not directly set line-to-line spacing,
%   known as \baselineskip. Instead, \baselineskip is calculated from other
%   settings, so that "occupied height" fills "available height."
% See the above theory of layout, for the equations. Solve for \baselineskip =
%   (\@AvailableHeight-1.3\@SetFontSize)  divided by
%   (\@HeadJump+\@LinesPerPage+\@FootJumpFix)
%
\xdef\@AdjLPP{\fpeval{\@HeadJump+\@LinesPerPage+\@FootJumpFix}} % used often
\edef\@tempBLS{%
  \fpeval{(\@AvailableHeight-1.3\@SetFontSize) / \@AdjLPP}%
} %
\FPtrunc\@tempBLS{\@tempBLS}{2} % round down to 2 decimalplaces
\gsetlength\baselineskip{\@tempBLS pt}
%
% Error if \baselineSkip is too tight, in relation to normal em size:
\ifdimcomp{\baselineskip}{<}{1.2\@SetFontSize}{%
  \ClassError{novel}{Calculated baselineskip is too small}%
   {Default baselineskip is calculated from normal em size, ^^J%
     available text height, and lines per page. Result is too small. ^^J%
    Change something, then try again.}%
}{}%
%% end calculate baselineskip.


%% FINISH LAYOUT (but post-layout deals with special class options)
%% ----------------------------------------------------------------------------
% Caution if font size is small:
\ifdimcomp{\@SetFontSize}{<}{10pt}{ %
  \typeout{^^JClass `novel' Alert: Normal font at less than 10pt. ^^J%
    Whether or not this is too small, depends on circumstances. ^^J%
    Beware if you use footnotes, which are smaller. ^^J%
  }
}{} %
\ifdimcomp{\@SetFontSize}{<}{8.03pt}{ % 8 PostScript points (TeX bp)
  \ClassWarning{novel}{^^JNormal font at less than 8 points. ^^J%
    This is usually undesirable. May be rejected by some print services. ^^J%
  }
}{} %
% Default Media Size is same as Trim Size, unless \SetMediaSize used:
\if@MediaSize\else
    \gsetlength\paperwidth{\@TrimWidth}
    \gsetlength\paperheight{\@TrimHeight}
\fi
% Sanity check for cover art, which needs bleed:
\if@coverart
  \setlength\@tempLength{\paperwidth-\@TrimWidth}
  \ifthenelse{\dimtest{\@tempLength}{<}{6mm}}{%
    \ClassWarning{novel}{^^JBIG BAD WARNING! Insufficient bleed width ?^^J%
    Commercial printers generally require 0.125in (3mm) bleed,^^J%
    on all four sides of the Trim. But your dimensions do not provide this.^^J%
    Perhaps you need to increase the Media Width ?^^J}
  }{}
  \ifthenelse{\dimtest{\@tempLength}{>}{0.5in}}{%
    \ClassWarning{novel}{^^JBIG BAD WARNING! Too much bleed width ?^^J%
    Commercial printers generally require 0.125in (3mm) bleed,^^J%
    on all four sides of the Trim. Sometimes as much as 0.25in (6mm) each.^^J%
    But your dimensions provide more than this.
    Perhaps you need to decrease the Media Width ?^^J}
  }{}
  \setlength\@tempLength{\paperheight-\@TrimHeight}
  \ifthenelse{\dimtest{\@tempLength}{<}{5.83mm}}{% allows for pixel rounding
    \ClassWarning{novel}{^^JBIG BAD WARNING! Insufficient bleed height ?^^J%
    Commercial printers generally require 0.125in (3mm) bleed,^^J%
    on all four sides of the Trim. But your dimensions do not provide this.^^J%
    Perhaps you need to increase the MediaSize ?^^J}
  }{}
  \ifthenelse{\dimtest{\@tempLength}{>}{0.507in}}{% allows for pixel rounding
    \ClassWarning{novel}{^^JBIG BAD WARNING! Too much bleed height ?^^J%
    Commercial printers generally require 0.125in (3mm) bleed,^^J%
    on all four sides of the Trim. Sometimes as much as 0.25in (6mm) each.^^J%
    But your dimensions provide more than this.
    Perhaps you need to decrease the MediaSize ?^^J}
  }{}
\fi
% \textheight, normal font size, etc:
\gsetlength\textheight{\@LinesPerPage\baselineskip}
\renewcommand\normalsize{%
  \@setfontsize\normalsize{\strip@pt\@SetFontSize}{\strip@pt\baselineskip}%
}
\normalsize % from this point, the "real" normal font size is effective
%

%
\if@HasHeader
  % \headheight is mis-named. Text "height" is supposed to be measured upward
  %   from the baseline. But \headheight is measured from 0.3em below
  %   the baseline, to allow for descenders. Thus, to provide actual "height"
  %   of 1em, \headheight must be set to 1.3em:
  \gsetlength\headheight{1.3\@SetFontSize}
  % \headsep is a confusing term. It is the separation between the nominal
  %   0.3em descenders of header text, and one baseline above the baseline
  %   of the top line of main text. Got that? Let me do the thinking for you:
  \gsetlength\headsep{\@HeadJump\baselineskip-\baselineskip-0.3\@SetFontSize}
\else % no header, no problem:
  \gsetlength\headheight{0pt}
  \gsetlength\headsep{0pt}
\fi
% \oddsidemargin is at the left (inner, spine edge) of recto pages.
% Measured 1in (72.27pt) inside MediaBox, to the textblock. May be negative.

  \gsetlength\oddsidemargin{%
    \@InnerMargin+0.5\paperwidth-0.5\@TrimWidth-72.27pt%
  }

%
% \evensidemargin is at the left (outer edge) of verso pages.

  \gsetlength\evensidemargin{%
    \@OuterMargin+0.5\paperwidth-0.5\@TrimWidth-72.27pt%
  }

%
\if@closecrop
  \gsetlength\oddsidemargin{-0.9in}
  \gsetlength\evensidemargin{-0.9in}
\fi
%
% \topmargin is measured from 1in (72.27pt) below the top of the MediaBox,
%   to the top of whatever comes first (header or textblock). May be negative.
% For consistency, the topmost baseline (header or main text) will be
%   positioned at 1em below the margin.

  \gsetlength\topmargin{\@TopMargin+0.5\paperheight-0.5\@TrimHeight-72.27pt}
  \if@HasHeader\else
    \gsetlength\topmargin{\topmargin-\baselineskip+\@SetFontSize}
  \fi

% novel.cls sets a tentative em size (probably 10pt) so that packages requiring
%   an integer point size of 10, 11, or 12 will load without complaint.
% Then, the real point size is established here, when it is too late for
%   such packages to complain. Sneaky, eh?
% However, TeX places a strut in the header, rising 0.7x tentative size above
%   the header baseline. If the real size is too small, then the strut is
%   too large, which displaces the header text downward, simultaneously
%   shrinking the headsep and possibly affecting the textblock position.
% This unlikely problem cannot be fixed by adjusting the headheight, but it
%   can be fixed by adjusting the topmargin and headsep to compensate:
\ifdimcomp{\@SetFontSize}{<}{\@TentativeEmN pt}{ %
  \setlength\@tempLength{\@TentativeEmN pt}
  \gsetlength\topmargin{\topmargin-0.7\@tempLength+0.7\@SetFontSize}
  \gsetlength\headsep{\headsep+0.7\@tempLength-0.7\@SetFontSize}
}{} %
%%
% It seems that, unless specified by user, TeX may place the top text baseline
%   in a vertical position that depends on the height of text in that line.
% That height may vary, depending on ascenders or diacriticals there.
% In order to fix the position, \topskip gets a non-flexible setting.
% The best value is normal baselineskip, partly because it looks right,
%   and also to avoid underfull vboxes on nearly every page.
\gsetlength\topskip{\baselineskip} % absorber
% In `novel' class, footers are done in an unusual manner, as explained above.
% To fix the position of the virtual footer baseline:
\gsetlength\footskip{\baselineskip}
%% Sanity check: Trim Size must be contained within Media Size.
\ifthenelse{%
  \dimtest{\@TrimWidth}{>}{\paperwidth} %
  \OR \dimtest{\@TrimHeight}{>}{\paperheight}%
}{%
  \ClassError{novel}{Media Size too small for TrimSize}%
  {You wrote \string\SetMediaSize\space with length(s) too small ^^J%
   for the default Trim Size or your values in \string\SetTrimSize.}%
}{} %
% end sanity check
%% end finish layout.


%%
\endinput
%%
%% End of file `novel-CalculateLayout.sty'.