summaryrefslogtreecommitdiff
path: root/macros/latex/contrib/beamer-contrib/spot/spot.dtx
blob: cd8d2af9638e4379f133702c876a3f080c150c7a (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
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
% \iffalse meta-comment
%
% spot.ins
% Copyright 2010 by Anders O.F. Hendrickson (ahendric@cord.edu)
%
% This work may be distributed and/or modified under the
% conditions of the LaTeX Project Public License, either version 1.3
% 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 1.3 or later is part of all distributions of LaTeX
% version 2005/12/01 or later.
%
% This work has the LPPL maintenance status `maintained'.
% 
% The Current Maintainer of this work is Anders O.F. Hendrickson.
%
% This work consists of the files spot.dtx and spot.ins
% and the derived file spot.sty.
%
% \fi
%
% \iffalse
%<*driver>
\ProvidesFile{spot.dtx}
%</driver>
%<package>\NeedsTeXFormat{LaTeX2e}[1999/12/01]
%<package>\ProvidesPackage{spot}
%<*package>
    [2011/05/09 v1.1 Spotlight highlighting]
%</package>
%
%<*driver>
\documentclass{ltxdoc}
\usepackage{spot}
\usepackage{fancyvrb}
\EnableCrossrefs         
\CodelineIndex
\RecordChanges
\begin{document}
  \DocInput{spot.dtx}
  \PrintChanges
  %\PrintIndex
\end{document}
%</driver>
% \fi
%
% \CheckSum{360}
%
% \CharacterTable
%  {Upper-case    \A\B\C\D\E\F\G\H\I\J\K\L\M\N\O\P\Q\R\S\T\U\V\W\X\Y\Z
%   Lower-case    \a\b\c\d\e\f\g\h\i\j\k\l\m\n\o\p\q\r\s\t\u\v\w\x\y\z
%   Digits        \0\1\2\3\4\5\6\7\8\9
%   Exclamation   \!     Double quote  \"     Hash (number) \#
%   Dollar        \$     Percent       \%     Ampersand     \&
%   Acute accent  \'     Left paren    \(     Right paren   \)
%   Asterisk      \*     Plus          \+     Comma         \,
%   Minus         \-     Point         \.     Solidus       \/
%   Colon         \:     Semicolon     \;     Less than     \<
%   Equals        \=     Greater than  \>     Question mark \?
%   Commercial at \@     Left bracket  \[     Backslash     \\
%   Right bracket \]     Circumflex    \^     Underscore    \_
%   Grave accent  \`     Left brace    \{     Vertical bar  \|
%   Right brace   \}     Tilde         \~}
%
%
% \changes{v1.0}{2010/09/21}{Initial version}
%
% \GetFileInfo{spot.sty}
%
% \DoNotIndex{\newcommand,\newenvironment,\def}
% 
%
% \title{The \textsf{spot} package: \\
%        spotlight highlighting for Beamer\thanks{This document
%   corresponds to \textsf{spotlight}~\fileversion, dated \filedate.}}
% \author{Anders Hendrickson\\ Concordia College, Moorhead, MN \\ \texttt{ahendric@cord.edu}}
%
% \maketitle
%
% \providecommand\barg[1]{%
% {\ttfamily\char`<}\meta{#1}{\ttfamily\char`>}}
% \providecommand\TikZ{Ti\emph{k}Z}
%
% \section{Introduction}
%
% 
% Beamer's |\alert| command is designed to call the viewer's attention
% to certain parts of the slide, but under some circumstances it can be less effective than desired.
% First, because the actual colors produced depend on the projector 
% hardware used and the ambient lighting in the room,
% you can find to your dismay that the color change 
% provided by |\alert| is barely discernible onscreen.
% Of course you can fiddle with |\setbeamercolor{alerted text}|\marg{color}
% to achieve better results on your own projector,
% but you may still face surprises when taking your presentation to another institution.
% Moreover, the |\alert| command is often ineffective at highlighting
% just one or two characters on a full slide;
% in such a situation, 
% a color change alone may not be striking enough to draw the viewer's eye.
% For just such circumstances, this package provides a |\spot| command 
% to paint a ``spotlight'' of color painted behind the highlighted text, 
% as in \spot{this example.}
% 
%
%
% \section{Usage}\label{sect:usage}
% \subsection{General Usage}
%
%
% \DescribeMacro{\spot}
% The |\spot| command has the following syntax:
% \begin{center}
% |\spot|\barg{overlay spec}\parg{node name}\oarg{node options}\marg{highlighted text}
% \end{center}
% The first three parameters, \barg{overlay spec}, \parg{node name}, and \oarg{node options}, 
% are optional,
% and any combination of them may be omitted,
% but their order must not change.
% For example, |\spot<5->[fill=red]{George}| is legal,
% but entering |\spot[star](mynode){Joe}| will produce erroneous output.
%
% The \meta{overlay spec} should be a standard Beamer overlay specification;
% for example,
% |\spot<2-3>{Fred}| highlights the word ``Fred'' only on slides 2 and 3.
% The actual ``spotlight'' shape is a \TikZ\ node.
% If you wish to access the node 
% later---for example, to point an arrow at it---you
% can specify a \meta{node name}.
% Consider the following example:
% \begin{quote}
% \begin{tabular}{p{1.5in}p{3in}}
% \spot*(first){We} can draw an arrow from the first word of this sentence to the \spot*(last){last}.
% \tikz[remember picture, overlay]{\draw (first) to[->] (last);}
% & \tt
% |\spot(first){We}| can draw an arrow from the first word of this sentence to the |\spot(last){last}.|
% |\tikz[remember picture, overlay]{| | \draw (first) to[->] (last);}|
% \end{tabular}
% \end{quote}
% \dospots
%
%
% The default behavior of |\spot| is to surround its argument with a gold-colored ellipse,
% most intense at its center and fading towards the edges.
% That behavior can be altered---for example, to change the shape or color---for 
% a specific instance of |\spot| by specifying \meta{node options}.
% Consider the following example:
% \begin{quote}
% \begin{tabular}{p{1.5in}p{3in}}
% To \spot*[fill=blue!50]{be,}
% or not to
% \spot*[star, star points=8]{be:}
% that \spot*[ball color=red]{is} the 
% \spot*[path fading=east]{question.}
% & \tt
% To |\spot*[fill=blue!50]{be,}|
% or not to
% |\spot*[star, star points=8]{be:}|
% that |\spot*[ball color=red]{is}| the 
% |\spot*[path fading=east]{question.}|
% \end{tabular}
% \end{quote}
% \dospots
%
% For a complete understanding of possible \meta{node options},
% please see the PGF/\TikZ\ documentation.
% Of particular note is that |path fading=none| will eliminate the fading,
% causing the node to \spot*[path fading=none]{overlap} surrounding text.
% To change the default behavior for subsequent calls to |\spot|, 
% the following commands are provided.
%
% \DescribeMacro{\setspotlightcolor}
% \DescribeMacro{\resetspotlightcolor}
% \DescribeMacro{\spotlightcolor}
% The command |\setspotlightcolor|\marg{color} makes all subsequent invocations of |\spot|
% use the specified \meta{color}.
% The default shade of gold is named |spotlightgold|, 
% and may be restored with the command |\resetspotlightcolor|.
% The current color is saved in the macro |\spotlightcolor|,
% making commands such as |\setspotlightcolor{\spotlightcolor!50}| possible.
% Note that if |fill=|\meta{color} is given in the \meta{node options}
% or with |\setspotlightstyle|, 
% it takes precedence over the \meta{color} in |\spotlightcolor|.
%
% \DescribeMacro{\setspotlightstyle}
% \DescribeMacro{\resetspotlightstyle}
% \DescribeMacro{\spotlightnodeoptions}
% The command |\setspotlightstyle|\marg{node options} adds \meta{node options} 
% to the nodes produced by all subsequent invocations of |\spot|.
% The effect of multiple calls is cumulative.
% Default options may be restored by
% |\resetspotlightstyle|.
% The current options are saved in the macro |\spotlightnodeoptions|.
% 
% \begin{quote}
% \begin{tabular}{p{1.5in}p{3in}}
% & |\setspotlightcolor{red!50}| \\
% & |\spot{A} \quad| \\
% & |\setspotlightstyle{star, fill=green!50}| \\
% & |\spot{B} \quad| \\
% \setspotlightcolor{red!50}
% \spot*{A} \quad
% \setspotlightstyle{star, fill=green!50}
% \spot*{B} \quad
% \setspotlightstyle{star points=7}
% \spot*{C} \quad
% \resetspotlightstyle
% \spot*{D} \quad
% \resetspotlightcolor
% \spot*{E}
% & |\setspotlightstyle{star points=7}| \\
% & |\spot{C} \quad| \\
% & |\resetspotlightstyle \spot{D} \quad| \\
% & |\resetspotlightcolor \spot{E}| \\
% \end{tabular}
% \end{quote}
% \resetspotlightcolor
% \dospots
%
% \subsection{Non-Beamer Usage}\label{sect:nonbeamerusage}
%
% Although the |spot| package is chiefly designed for use with Beamer,
% it may also be used in documents
% of other classes.
% There are two peculiarities,\label{page:2pec} 
% however, the reasons for which will be explained in section \ref{sect:strategy}.
% \DescribeMacro{\spot*}
% First, if |\spot| is used within a |\parbox|,
% a |minipage| environment,
% a header or footer,
% or a |p| column in a |tabular| environment,
% the error message
% ``|LaTeX Error: Float(s) lost|'' will result.
% The remedy is to use the the starred version |\spot*| instead,
% and to follow the instructions in the following paragraph.
%
% \DescribeMacro{\dospots}
% Second, if the last call to |\spot| on a page is
% in math mode, in a \TeX\ inner mode (such as a |tabular| environment),
% or the starred version |\spot*|,
% then the command |\dospots| must be issued somewhere later on that same page,
% after the math mode or |tabular| or |\parbox| has ended.
% (The actual criterion is that |\dospots| must be able to call |\marginpar|,
% which cannot be done in those environments.)
% If the page ends before a |\dospots| is encountered, 
% an error message will be generated.
% 
% \DescribeMacro{\dospotsheader}
% \DescribeMacro{\dospotsfooter}
% Remembering to place a |\dospots| after each problematic |\spot|
% can be a hassle.
% The best solution is to use the |fancyhdr| package
% to place the command |\dospotsheader|
% or its synonym |\dospotsfooter|
% into a header or footer appearing on every page,
% obviating the need for any manual |\dospots|.
% Moreover, if a spotlight is desired \emph{within} a header, footer, or marginpar, 
% |\spot*| should be used and |\dospotsheader| or |\dospotsfooter| should follow.
%
% 
%
% 
% \section{Strategy}\label{sect:strategy}
% \VerbatimFootnotes
% This section describes the mechanism |spot| uses to draw its spotlights.
% It would be simple enough to wrap the 
%  \makeatletter
%  \tikz[baseline]{
%     \path[use as bounding box] 
%                    node[anchor=base, inner sep=0, outer sep=0, opacity=0] 
%                    (temp) {highlighted text};
%              \path (temp) 
%                    node[anchor=center, outer sep=0,
%                         shape=ellipse, inner sep=0.5ex, 
%                         fill=\spotlightcolor, path fading=spot@fade] {highlighted text};
%    }
%  \makeatother
% within a \TikZ\ node, keeping it in line with its surroundings,
% but the result is not perfect.  The preceding highlighting\footnote{Produced with
%  \begin{verbatim}
%    \tikz[baseline]{
%      \path[use as bounding box] 
%        node[anchor=base, inner sep=0, outer sep=0, opacity=0] 
%         (temp) {highlighted text};
%      \path (temp) 
%        node[anchor=center, outer sep=0,
%             shape=ellipse, inner sep=0.5ex, 
%             fill=\spotlightcolor, path fading=spot@fade] {highlighted text};}
%  \end{verbatim}
% }
% was painted over previous text
% but under subsequent text, creating both an uneven effect
% and an unintentional emphasis on the beginning of the following word.
% The solution is to leave a blank space in the text,
% coming back once the entire frame has been typeset
% to draw the text and its highlighting over their surroundings.
% 
% Suppose then that |\spot<2>{foo}| is called in a Beamer frame.
% On slide 1 of the frame,
% the text |foo| is typeset as the sole node in a \TikZ\ picture,
% with node options chosen so that it occupies
% its place in the paragraph just like ordinary typeset text.
% The node is given a name such as |spot@vii|,
% and the |remember picture| option is used.
%
% When slide 2 is typeset,
% the node |spot@vii| is drawn as before, except with |opacity=0| so that it is transparent.
% After the contents of the entire slide are typeset,
% another \TikZ\ picture uses the |overlay| option 
% to return to the location of |spot@vii|
% and typeset |foo| in a node with 
% a suitably eye-catching shape, |fill| color, and fading.
%
% In Beamer, the code to paint the highlighted node is attached to |\end{frame}|.
% The challenge for implementing |spot| in classes other than Beamer
% is the lack of a hook for the end of a page;
% even the |afterpage| package cannot return to the previous page to typeset new material.
% The solution used is to insert the |\spot@paintspot| macro
% into a |\marginpar|.
% This is the source of the two peculiarities mentioned on page \pageref{page:2pec},
% for under certain circumstances, \LaTeX\ cannot process a |\marginpar|
% correctly.
% These circumstances include \TeX's inner vertical mode, display math, and |\parbox|es.
% In these situations 
% |spot| must save its painting commands for later.
% The command |\dospots|, called from a ``safe'' location,
% inserts those saved commands into a |\marginpar|.
% The alternative commands |\dospotsheader| and |\dospotsfooter|
% execute the saved paint commands immediately,
% making them suitable for inclusion in a header or footer.
% Because this second mechanism, though more reliable, 
% places an extra burden on the user, 
% it was not chosen as the default behavior for |\spot|.
%
% The starred version |\spot*| uses the second mechanism in place of the first.
% Moreover, the |\spot| macro will also switch to the second mechanism
% when it can detect the necessity.
% If |\ifinner| is true, then |\marginpar| would fail;
% likewise if |\ifmmode| is true, then \LaTeX\ might well be in display math mode
% where |\marginpar| fails;
% in these situations, |\spot| acts like |\spot*|.
% Unfortunately, if |\spot| is called within a |\parbox|, 
% there is no test that can make |\spot| aware of that fact,
% and the user will see
% |LaTeX Error:  Float(s) lost.|
% This warning is an indication that even \LaTeX\ itself could not tell in advance
% whether |\marginpar| would work properly or not.
% 
% 
%
% \section{Limitations and Tips}
% \begin{itemize}
%
% \item Because |\spot{foo}| places the text |foo| in a \TikZ\ node,
% it will not allow line breaks within |foo|.
% For highlighting that permits automatic line breaking, consider the |\hl| command of the |soul| package.
%
% \item The |\spot| command does not work well in a Beamer frame
% broken into multiple slides by |allowframebreaks|.
%
% \item In non-Beamer class, spotlights meant for the bottom of one page
% may sometimes show up at the bottom of the next page.
% 
% 
%
% \item It is possible to call |\spot| in math mode, 
% but as the argument will be set in a box within a \TikZ\ node,
% the results may need tinkering.
% For example, |$a^{\spot{b}}$| produces $a^{\spot{b}}$,
% not $a^{\spot{\scriptstyle b}}$;
% to make the superscript the correct size,
% you must write |$a^{\spot{\scriptstyle b}}$|.
% Likewise to produce $a\mathbin{\spot{=}}b$ requires writing
% |$a\mathbin{\spot{=}}b$|, since merely writing
% |$a\spot{=}b$| produces the poorly spaced $a\spot{=}b$.
% \dospots
%
% \item As mentioned in section \ref{sect:nonbeamerusage},
% when using |spot| in a document class other than Beamer,
% it is best to include |\dospotsheader| in a header appearing on every page.
% A minimal solution is to put the following in the preamble:
% \begin{verbatim}
%   \usepackage{fancyhdr}
%   \pagestyle{fancy}
%   \fancyhf{}
%   \rhead{\dospotsheader}
% \end{verbatim}
% \end{itemize}
% 
% 
% \StopEventually{}
%
% \section{Implementation}
% 
% \subsection{Packages and Hooks}
%
% The \TikZ\ package must be loaded with the necessary libraries.
%    \begin{macrocode}
\RequirePackage{tikz}
\usetikzlibrary{shapes}
\usetikzlibrary{fadings}
%    \end{macrocode}
%
% We next check whether we are in the Beamer class
% or not, and we abbreviate |\expandafter| in the usual way.
%    \begin{macrocode}
\newif\ifspot@beamer
\@ifundefined{beamer@frameslide}{\spot@beamerfalse}{\spot@beamertrue}
\let\xa=\expandafter
%    \end{macrocode}
%
% In Beamer, we will need hooks for running code at the beginning and end of each frame.
% The commands |\AtEveryBeginFrame| and |\AtEveryEndFrame| store commands to be run in every frame,
% \changes{v1.1}{2011/05/09}{Fixed bug with Beamer's title command}
% while the command |\AtEndFrame| applies only to the current frame.
% We repeat the last token of |\beamer@frameslide|, namely |\beamer@checkframetitle|,
% so that |\beamer@frameslide| can still detect the presence of a frame title.
%    \begin{macrocode}
\ifspot@beamer
  \g@addto@macro\beamer@frameslide{\spot@everybeginframe@hook\beamer@checkframetitle}
%    \end{macrocode}
% Whereas |\g@addto@macro| makes it easy to add
% |\spot@everybeginframe@hook| to the end of the |\begin{beamer@frameslide}| code,
% adding hooks to be executed right \emph{before}
% the existing |\end{beamer@frameslide}| code is a little more involved.
%    \begin{macrocode}
  \let\spot@oldmaterial=\endbeamer@frameslide
  \def\spot@newmaterial{%
        \spot@endframe@hook%
        \gdef\spot@endframe@hook{}%
        \spot@everyendframe@hook}
  \xa\xa\xa\def
  \xa\xa\xa\endbeamer@frameslide
  \xa\xa\xa{%
        \xa\spot@newmaterial\spot@oldmaterial}%
%    \end{macrocode}
% Having placed hooks into the |beamer@frameslide| environment,
% we now initialize those hooks as empty
% and create the commands |\AtEndFrame|, |\AtEveryEndFrame|, and |\AtEveryBeginFrame|.
%    \begin{macrocode}
  \def\spot@endframe@hook{}
  \def\spot@everyendframe@hook{}
  \def\spot@everybeginframe@hook{}
  \long\def\AtEndFrame#1{\g@addto@macro\spot@endframe@hook{#1}}
  \long\def\AtEveryEndFrame#1{\g@addto@macro\spot@everyendframe@hook{#1}}
  \long\def\AtEveryBeginFrame#1{\g@addto@macro\spot@everybeginframe@hook{#1}}
%    \end{macrocode}
% In classes other than Beamer, we will need the |afterpage| package to run code between pages.
%    \begin{macrocode}
\else
  \RequirePackage{afterpage}
\fi
%    \end{macrocode}
%
%
%
% \subsection{Spotlight options}
% We next define the options.  
% The |\spotlightcolor| macro stores the working color;
% it can be edited with the commands |\setspotlightcolor| and |\resetspotlightcolor|.
%    \begin{macrocode}
\def\spotlightcolor{spotlightgold}
\def\setspotlightcolor#1{\xdef\spotlightcolor{#1}}
\def\resetspotlightcolor{\gdef\spotlightcolor{spotlightgold}}
%    \end{macrocode}
% Likewise the command |\spotlightnodeoptions| stores additional node options chosen by the user.
% The command |\setspotlightstyle| adds to it, and |\resetspotlightstyle| empties it.
%    \begin{macrocode}
\def\spotlightnodeoptions{}
\def\setspotlightstyle#1{\g@addto@macro\spotlightnodeoptions{#1, }}
\def\resetspotlightstyle{\gdef\spotlightnodeoptions{}}
%    \end{macrocode}
% Finally, here are the default color and fading.
%    \begin{macrocode}
\definecolor{spotlightgold}{RGB}{255,204,51}
\tikzfading[name=spot@fade,
            inner color=transparent!0,
            outer color=transparent!60]
%    \end{macrocode}
% The count register |\c@spot@spots| numbers each spotlight on the frame or page.
%    \begin{macrocode}
\newcount\c@spot@spots
\c@spot@spots=1
\ifspot@beamer
  \AtEveryBeginFrame{\global\c@spot@spots=1\relax}
\else
  \afterpage{\global\c@spot@spots=1\relax}
\fi
%    \end{macrocode}
%
%
%
%
% \subsection{Input parsing}
% \begin{macro}{\spot}
% The macro |\spot| comes in starred and unstarred versions.
% We first check for the presence of the star,
% and set a flag if it is present.
%    \begin{macrocode}
\newif\ifspot@star
\spot@starfalse
\def\spot{\@ifnextchar*{\spot@star}{\spot@nostar}}
\def\spot@star#1{\global\spot@startrue\spot@nostar}
%    \end{macrocode}
% \end{macro}
% \begin{macro}{\spot@nostar}
% As described in section \ref{sect:usage}, 
% the full syntax of |\spot| is 
%   \begin{center}
%     |\spot|\barg{overlay spec}\parg{node name}\oarg{node options}\marg{highlighted text}
%   \end{center}
% with each of \meta{overlay spec}, \meta{node name}, and \meta{node options} being optional.
% If any is not specified, we fill in the appropriate default value.
%
% The default overlay specification is |<1->|. 
%    \begin{macrocode}
\def\spot@nostar{%
  \@ifnextchar<{\spot@in}{\spot@in<1->}%
}
%    \end{macrocode}
% \end{macro}
% \begin{macro}{\spot@in}
% The default \meta{node name} is |spot@dummynode|.
%    \begin{macrocode}
\def\spot@in<#1>{%
  \@ifnextchar({\spot@inte<#1>}%
               {\spot@inte<#1>(spot@dummynode)}%
}
%    \end{macrocode}
% \end{macro}
% \begin{macro}{\spot@inte}
% The default is to have no extra \meta{node options}.
%    \begin{macrocode}
\def\spot@inte<#1>(#2){%
  \@ifnextchar[{\spot@intern<#1>(#2)}{\spot@intern<#1>(#2)[]}%
}
%    \end{macrocode}
% \end{macro}
% \begin{macro}{\spot@intern}
% Because the spotlight is painted after the rest of the page is drawn,
% it is important to expand the node options now
% (including |\spotlightcolor| and the user-defined |\spotlightnodeoptions|),
% so that they will not be affected by redefinitions later on the page.
% Note that the order of parameters is changed to make the |\expandafter|s work.
%    \begin{macrocode}
\def\spot@intern<#1>(#2)[#3]#4{%
  \edef\spot@totaloptions{fill=\spotlightcolor, \spotlightnodeoptions, #3}%
  \xa\spot@internal\xa[\spot@totaloptions]<#1>(#2){#4}%
}
%    \end{macrocode}
% \end{macro}
% \begin{macro}{\spot@internal}
% Finally, we are ready to call the macros which actually do the work,
% depending on whether we are running Beamer or some other class.
% We return the parameters to their normal order.
%    \begin{macrocode}
\def\spot@internal[#1]<#2>(#3)#4{%
  \ifspot@beamer%
    \spot@internal@beamer<#2>(#3)[#1]{#4}%
  \else%
    \spot@internal@static<#2>(#3)[#1]{#4}%
  \fi%
}
%    \end{macrocode}
% \end{macro}
%
%
%
%
%
%
%
%
%
% \subsection{Beamer version}
%
% \begin{macro}{\spot@internal@beamer}
% The macro |\spot@internal@beamer|
% implements the |\spot| command when used in a Beamer presentation.
%    \begin{macrocode}
\def\spot@internal@beamer<#1>(#2)[#3]#4{%
%    \end{macrocode}
% The text to be highlighted is first saved in a box named something like |\spot@box@vii|,
% where the roman numeral represents the spot counter |\c@spot@spots|.
% In this way it will automatically have the correct font size and shape (italics, boldface, etc.).
% It is set in math mode if necessary.
% For the sake of readability of the code, |\spot@currentbox| is let equal to |\spot@box@vii|.
%    \begin{macrocode}
  \@ifundefined{spot@box@\romannumeral\c@spot@spots}%
          {\xa\newbox\csname spot@box@\romannumeral\c@spot@spots\endcsname}{}%
  \ifmmode
    \global\xa\setbox\csname spot@box@\romannumeral\c@spot@spots\endcsname=\hbox{$#4$}%
  \else
    \global\xa\setbox\csname spot@box@\romannumeral\c@spot@spots\endcsname=\hbox{#4}%
  \fi
  \xa\let\xa\spot@currentbox\csname spot@box@\romannumeral\c@spot@spots\endcsname%
%    \end{macrocode}
% Now we are ready to set the text.
% On the highlighted slides, we actually produce two \TikZ\ nodes at this time.
% The first is merely a transparent copy of the text itself;
% the second is a transparent copy of the entire highlighted node shape,
% and receives the \meta{node name} called by the user.
% We require the first node (with the |use as bounding box| option) 
% so as to fit the text seamlessly in line with its surroundings.
% The second node, bearing \meta{node name}, must be drawn now, so that the user can 
% refer to \meta{node name}
% within the frame;
% the \meta{node name} could not simply be attached to the visible spotlight,
% since that is drawn with |\AfterEndFrame|, \emph{after} all the user's code has been processed.
% On unhighlighted slides, we simply draw an opaque copy of the text in a \TikZ\ node.
%    \begin{macrocode}
  \tikz[remember picture, baseline]{
    \alt<#1>{\path[use as bounding box] 
                   node[anchor=base, inner sep=0, outer sep=0, opacity=0] 
                   (spot@\romannumeral\c@spot@spots) {\usebox\spot@currentbox};
             \path (spot@\romannumeral\c@spot@spots) 
                   node[anchor=center, outer sep=0,
                        shape=ellipse, inner sep=0.5ex, 
                        #3, opacity=0] (#2) {\usebox\spot@currentbox};}
            {\path node[anchor=base, inner sep=0, outer sep=0, opacity=1]
                       (#2) {\usebox\spot@currentbox};}
    }%
%    \end{macrocode}
% Finally, we save the information needed to paint the spotlight at the end of the slide.
% Sometimes calling |\AtEndFrame|
% adds a little extra height to the frame's contents,
% which could cause a slight movement of the frame between highlighted and unhighlighted slides.
% We therefore make a call to |\AtEndFrame| on unhighlighted slides
% as well, to ensure that the same extra height be added
% even when we're not painting spotlights.
%    \begin{macrocode}
  \alt<#1>{\xa\spot@savepaint\xa{\romannumeral\c@spot@spots}[#3]}%
          {\AtEndFrame{\rule{0pt}{0pt}}}%
%    \end{macrocode}
% Finally, we increment the counter |\c@spot@spots| and end the macro.
%    \begin{macrocode}
  \global\advance\c@spot@spots by 1\relax%
}
%    \end{macrocode}
% \end{macro}
% \begin{macro}{\spot@savepaint}
% The following macro saves the actual spotlight-drawing command to be executed at the end of the slide.
% The first parameter is a roman numeral labeling the spotlight,
% while the second contains the node options.
%    \begin{macrocode}
\def\spot@savepaint#1[#2]{%
  \AtEndFrame{\spot@paintspot(spot@#1)[#2]{\usebox{\csname spot@box@#1\endcsname}}}%
}
%    \end{macrocode}
% \end{macro}
% \begin{macro}{\spot@paintspot}
% The command |\spot@paintspot| actually draws the spotlight at the saved location.
% Note that the first parameter is not the user-specified \meta{node name},
% but an automatically generated name such as |spot@vii|.
%    \begin{macrocode}
\def\spot@paintspot(#1)[#2]#3{%
  \begin{tikzpicture}[remember picture, overlay, baseline]
      \path (#1) node[anchor=center, outer sep=0,
                      shape=ellipse, inner sep=0.5ex, text opacity=1, 
                      path fading=spot@fade, text=black, #2] {#3};
  \end{tikzpicture}%
}
%    \end{macrocode}
% \end{macro}
%
%
%
% \subsection{non-Beamer version}
% To make the spotlight turn out correctly,
% it is vital to run |\spot@paintspot| \emph{after} all surrounding text has been typeset.
% Whereas in Beamer the code can be attached to 
% a hook in the |\end{frame}|,
% in other document classes
% we place the code in a |\marginpar|,
% which (being a \TeX\ insertion) is typeset after the rest of the page.
% If |\spot| is called in certain \TeX\ modes, however,
% |\marginpar| would produce an error.
% In this case, |\spot| saves up the commands to be placed into a |\marginpar| later.
% \begin{macro}{\spot@savedpaintcommands}
% \begin{macro}{\dospots}
% Whenever |\spot| is called, the |\spot@paintspot| commands 
% will be saved up in the macro |\spot@savedpaintcommands|.
% A subsequent call to |\dospots|, by the user if necessary, 
% executes those commands and resets the macro to empty.
%    \begin{macrocode}
\gdef\spot@savedpaintcommands{}
\def\dospots{%
  \marginpar{\spot@savedpaintcommands}%
  \gdef\spot@savedpaintcommands{}%
}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \begin{macro}{\dospotsheader}
% \begin{macro}{\dospotsfooter}
% Since headers and footers are also \TeX\ insertions,
% the |\spot@savedpaintcommands| could also be run there.
% The following commands are synonyms.
%    \begin{macrocode}
\def\dospotsheader{%
  \spot@savedpaintcommands%
  \gdef\spot@savedpaintcommands{}%
}
\let\dospotsfooter=\dospotsheader
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \begin{macro}{\spot@internal@static}
% Much of the code in |\spot@internal@static| is identical with that of |\spot@internal|.
% The chief difference is that the overlay specification is completely ignored.
%    \begin{macrocode}
\def\spot@internal@static<#1>(#2)[#3]#4{%
  \@ifundefined{spot@box@\romannumeral\c@spot@spots}%
          {\xa\newbox\csname spot@box@\romannumeral\c@spot@spots\endcsname}{}%
  \ifmmode
    \global\xa\setbox\csname spot@box@\romannumeral\c@spot@spots\endcsname=\hbox{$#4$}%
  \else
    \global\xa\setbox\csname spot@box@\romannumeral\c@spot@spots\endcsname=\hbox{#4}%
  \fi
  \xa\let\xa\spot@currentbox\csname spot@box@\romannumeral\c@spot@spots\endcsname%
  \tikz[remember picture, baseline]{
     \path[use as bounding box] 
            node[anchor=base, inner sep=0, outer sep=0, opacity=0] 
            (spot@\romannumeral\c@spot@spots) {\usebox\spot@currentbox};
     \path (spot@\romannumeral\c@spot@spots)
             node[anchor=center, inner sep=0, outer sep=0,
                  shape=ellipse, inner sep=0.5ex, 
                  #3, opacity=0] (#2) {\usebox\spot@currentbox};
    }%
  \xa\spot@static@savepaint\xa{\romannumeral\c@spot@spots}[#3]%
  \global\advance\c@spot@spots by 1\relax%
  \global\spot@starfalse%
}
%    \end{macrocode}
% \end{macro}
% \begin{macro}{\spot@static@savepaint}
% When |\spot@static@savepaint| is called, it first checks whether \TeX\ is in
% an inner mode and/or math mode, and whether the starred version |spot*| was used.  
% If any of these three conditions holds, a call to |\marginpar| would likely fail,
% so the |\marginpar| command is saved to be executed by a |\dospots| command sometime later,
% and |\spot@checkforlostspots| will be run after the current page is processed.
% Otherwise, 
% the appropriate |\spot@paintspot| command is immediately placed in a |\marginpar|,
% and any saved |\marginpar| commands are run at this time with |\dospots|.
% As with |\spot@savepaint|, the first parameter is
% the roman numeral identifying which spotlight is being painted,
% and the second contains the node options.
%    \begin{macrocode}
\def\spot@static@savepaint#1[#2]{%
  \def\spot@saveit{%
    \g@addto@macro\spot@savedpaintcommands{%
      \spot@paintspot(spot@#1)[#2]{\usebox{\csname spot@box@#1\endcsname}}}%
    \afterpage{\spot@checkforlostspots}%
  }%
  \ifspot@star
    \spot@saveit
  \else
    \ifinner
      \spot@saveit
    \else
      \ifmmode
        \spot@saveit
      \else
        \marginpar{\spot@paintspot(spot@#1)[#2]{\usebox{\csname spot@box@#1\endcsname}}}%
        \dospots
      \fi
    \fi
  \fi
}
%    \end{macrocode}
% \end{macro}
% \begin{macro}{\spot@checkforlostspots}
% Between pages, the command |\spot@checkforlostspots| checks whether any 
% |\spot@paintspot| commands were saved into |\spot@savedpaintcommands| but never 
% executed by a |\dospots|.  If so, it issues an error message to the user.
%    \begin{macrocode}
\def\spot@checkforlostspots{%
  \def\spot@empty{}%
  \ifx\spot@savedpaintcommands\spot@empty%
    \relax%
  \else%
    \bgroup
    \advance\count0 by -1
    \PackageError{spot}%
       {A \protect\dospots\space command is missing 
        from page \the\count0.\MessageBreak
        Some highlighted text will not appear in the output}%
       {If the last \protect\spot\space command on a 
        page is issued in math mode or a \MessageBreak
        TeX inner mode (such as a tabular environment), 
        it must be followed by a \MessageBreak
        \protect\dospots\space command somewhere later 
        on the page, outside such a mode.\MessageBreak
        You could also put \protect\dospotsheader\space 
        in a header or footer on each page.}
    \egroup
  \fi%
}
%    \end{macrocode}
% \end{macro}
%
%
% \Finale
\endinput