use strict;
use utf8;
+use POSIX qw(setsid);
use Pod::Usage;
use Getopt::Long;
use Cwd qw(getcwd abs_path);
=cut
my $mozembed;
+my $mozembed_first;
+my $mozembed_last;
GetOptions ("help|?" => \$help,
"last" => \$last,
"mozembed" => \$mozembed,
+ "mozembed-first" => \$mozembed_first,
+ "mozembed-last" => \$mozembed_last,
"n=s" => \$start,
"splash!" => \$splash,
"start=s" => \$start,
die "techtalk-pse: cannot use --start and --last options together\n"
if defined $last && defined $start;
-# --mozembed runs Gtk2::MozEmbed as a subprocess, because MozEmbed
-# is very crashy.
-if ($mozembed) {
- my $r = 0;
-
- my $w = Gtk2::Window->new ();
- my $vbox = Gtk2::VBox->new ();
- my $moz = Gtk2::MozEmbed->new ();
- my $bbox = Gtk2::HButtonBox->new ();
-
- $vbox->pack_start ($bbox, 0, 0, 0);
- $vbox->add ($moz);
- $w->fullscreen ();
- #$w->set_default_size (640, 480);
- $w->add ($vbox);
-
- $bbox->set_layout ('start');
- my $bnext = Gtk2::Button->new ("Next slide");
- $bnext->signal_connect (clicked => sub { $r = 0; Gtk2->main_quit });
- $bbox->add ($bnext);
-
- my $bback = Gtk2::Button->new ("Back");
- $bback->signal_connect (clicked => sub { $r = 1; Gtk2->main_quit });
- $bbox->add ($bback);
-
- my $bquit = Gtk2::Button->new ("Quit");
- $bquit->signal_connect (clicked => sub { $r = 2; Gtk2->main_quit });
- $bbox->add ($bquit);
- $bbox->set_child_secondary ($bquit, 1);
-
- $w->signal_connect (delete_event => sub {
- Gtk2->main_quit;
- return FALSE;
- });
- $w->show_all ();
-
- $moz->load_url ($ARGV[0]);
- Gtk2->main;
-
- exit $r;
-}
+# Run with --mozembed: see below.
+run_mozembed () if $mozembed;
+# Normal run of the program.
die "techtalk-pse: too many arguments\n" if @ARGV >= 2;
# Get the true name of the program.
}
}
+# Get the talk directory and set environment variable $talkdir
+# which is inherited by all the scripts.
+my $talkdir = getcwd;
+$ENV{talkdir} = $talkdir;
+
# Get the files.
my @files;
my %files;
-my %groups;
sub reread_directory
{
@files = ();
- %groups = ();
+ my $i = 0;
foreach (glob ("*")) {
- if (/^(\d+)([A-Z])?(?:-.*)\.(html|sh)$/) {
+ if (/^(\d+)(?:-.*)\.(html|sh)$/) {
print STDERR "reading $_\n" if $verbose;
my $seq = $1;
- my $pos = $2 || "A";
- my $ext = $3;
+ my $ext = $2;
warn "techtalk-pse: $_: command file is not executable (+x)\n"
if $ext eq "sh" && ! -x $_;
- my $h = { name => $_, seq => $1, pos => $2, ext => $3 };
+ my $h = { name => $_, seq => $1, ext => $2, i => $i };
push @files, $h;
$files{$_} = $h;
-
- $groups{$seq} = [] unless exists $groups{$seq};
- push @{$groups{$seq}}, $h;
+ $i++;
} else {
print STDERR "ignoring $_\n" if $verbose;
}
}
+
+ if (@files > 0) {
+ $files[0]->{first} = 1;
+ $files[$#files]->{last} = 1;
+ }
}
reread_directory ();
print STDERR "read ", 0+@files, " files\n" if $verbose;
my $w = Gtk2::AboutDialog->new;
$w->set_authors ("Richard W.M. Jones");
$w->set_comments (
- "Superior technical demonstration software\n".
- "\n".
- "Keys\n".
- "↑ — Go back one slide\n".
- "↓ — Go forward one slide\n"
+ "Superior technical demonstration software\n"
);
$w->set_program_name ("Tech Talk Platinum Supreme Edition (PSE)");
$w->set_version ("@VERSION@");
$w->set_website ("http://people.redhat.com/~rjones");
$w->set_license ("GNU General Public License v2 or above");
- $w->signal_connect (destroy => sub { Gtk2->main_quit });
- $w->show_all;
- Gtk2->main;
+ $w->run;
+ print STDERR "calling \$w->destroy on about dialog\n" if $verbose;
+ $w->destroy;
}
MAIN: while (1) {
print STDERR "go = $go\n" if $verbose;
last MAIN if $go eq "QUIT";
- my $i = 0;
- FOUND: {
- foreach (@files) {
- last FOUND if $files[$i]->{name} eq $current->{name};
- $i++;
- }
- die "internal error: cannot find \$current in \@files"
- }
- print STDERR "found current entry at i = $i\n" if $verbose;
+ my $i = $current->{i};
+ print STDERR "i = $i\n" if $verbose;
$i-- if $go eq "PREV" && $i > 0;
$i++ if $go eq "NEXT" && $i+1 < @files;
$current = $files[$i];
$_ = <STDIN>;
}
+ # Reread directory between slides.
reread_directory ();
if (defined $current && !exists $files{$current->{name}}) {
}
}
-sub show_slide {
+sub show_slide
+{
my $slide = shift;
+ # Display an HTML page.
if ($slide->{ext} eq "html") {
# MozEmbed is incredibly crashy, so we run ourself as a
# subprocess, so when it segfaults we don't care.
- my $cwd = getcwd;
- my $url = "file://" . $cwd . "/" . $slide->{name};
- my @cmd = ($0, "--mozembed", $url);
+ my @cmd = ($0, "--mozembed");
+ push @cmd, "--mozembed-first" if exists $slide->{first};
+ push @cmd, "--mozembed-last" if exists $slide->{last};
+ my $url = "file://$talkdir/" . $slide->{name};
+ push @cmd, $url;
+ print STDERR "running subcommand: ", join (" ", @cmd), "\n"
+ if $verbose;
system (@cmd);
- die "failed to execute subcommand: $!\n" if $? == -1;
+ die "failed to execute subcommand: ", join(" ", @cmd), ": $!\n"
+ if $? == -1;
if ($? & 127) {
# Subcommand probably segfaulted, just continue to next slide.
return "NEXT";
}
}
}
+ # Run a shell command.
elsif ($slide->{ext} eq "sh") {
- system ("PATH=.:\$PATH " . $slide->{name});
- return "NEXT";
+ my $pid;
+ # http://docstore.mik.ua/orelly/perl/cookbook/ch10_17.htm
+ local *run_process = sub {
+ $pid = fork ();
+ die "fork: $!" unless defined $pid;
+ unless ($pid) {
+ # Child.
+ POSIX::setsid ();
+ exec ("./".$slide->{name});
+ die "failed to execute command: ", $slide->{name}, ": $!";
+ }
+ # Parent returns.
+ };
+ local *kill_process = sub {
+ print STDERR "sending TERM signal to process group $pid\n"
+ if $verbose;
+ kill "TERM", -$pid;
+ };
+ run_process ();
+
+ my $r = "NEXT";
+
+ my $w = Gtk2::Window->new ();
+
+ my $s = $w->get_screen;
+ $w->set_default_size ($s->get_width, -1);
+ $w->move (0, 0);
+ $w->set_decorated (0);
+
+ my $bbox = Gtk2::HButtonBox->new ();
+ $bbox->set_layout ('start');
+
+ my $bnext = Gtk2::Button->new ("Next slide");
+ $bnext->signal_connect (clicked => sub { $r = "NEXT"; $w->destroy });
+ $bnext->set_sensitive (!(exists $slide->{last}));
+ $bbox->add ($bnext);
+
+ my $bback = Gtk2::Button->new ("Back");
+ $bback->signal_connect (clicked => sub { $r = "PREV"; $w->destroy });
+ $bback->set_sensitive (!(exists $slide->{first}));
+ $bbox->add ($bback);
+
+ my $brestart = Gtk2::Button->new ("Kill & restart");
+ $brestart->signal_connect (clicked => sub {
+ kill_process ();
+ run_process ();
+ });
+ $bbox->add ($brestart);
+
+ my $bquit = Gtk2::Button->new ("Quit");
+ $bquit->signal_connect (clicked => sub { $r = "QUIT"; $w->destroy });
+ $bbox->add ($bquit);
+ $bbox->set_child_secondary ($bquit, 1);
+
+ $w->add ($bbox);
+
+ $w->signal_connect (destroy => sub {
+ Gtk2->main_quit;
+ return FALSE;
+ });
+ $w->show_all ();
+
+ Gtk2->main;
+
+ kill_process ();
+ print STDERR "returning r=$r\n" if $verbose;
+ return $r;
}
}
+# If invoked with the --mozembed parameter then we just display a
+# single page. This is just to prevent crashes in MozEmbed from
+# killing the whole program.
+sub run_mozembed
+{
+ my $r = 0;
+
+ my $w = Gtk2::Window->new ();
+ my $vbox = Gtk2::VBox->new ();
+ my $moz = Gtk2::MozEmbed->new ();
+
+ my $bbox = Gtk2::HButtonBox->new ();
+ $bbox->set_layout ('start');
+
+ $vbox->pack_start ($bbox, 0, 0, 0);
+ $vbox->add ($moz);
+ $w->fullscreen ();
+ #$w->set_default_size (640, 480);
+ $w->add ($vbox);
+
+ my $bnext = Gtk2::Button->new ("Next slide");
+ $bnext->signal_connect (clicked => sub { $r = 0; $w->destroy });
+ $bnext->set_sensitive (!$mozembed_last);
+ $bbox->add ($bnext);
+
+ my $bback = Gtk2::Button->new ("Back");
+ $bback->signal_connect (clicked => sub { $r = 1; $w->destroy });
+ $bback->set_sensitive (!$mozembed_first);
+ $bbox->add ($bback);
+
+ my $bquit = Gtk2::Button->new ("Quit");
+ $bquit->signal_connect (clicked => sub { $r = 2; $w->destroy });
+ $bbox->add ($bquit);
+ $bbox->set_child_secondary ($bquit, 1);
+
+ $w->signal_connect (destroy => sub {
+ Gtk2->main_quit;
+ return FALSE;
+ });
+ $w->show_all ();
+
+ $moz->load_url ($ARGV[0]);
+ Gtk2->main;
+
+ exit $r;
+}
+
1;
=head1 TUTORIAL
+=head2 START WRITING A TALK
+
+[Before you start writing your real talk, I urge you to read
+L</WHAT MAKES A GOOD TALK> below].
+
+To start your talk, all you have to do is to make a new directory
+somewhere:
+
+ mkdir talk
+ cd talk
+
+A tech talk consists of HTML files ("slides") and shell scripts. The
+filenames must start with a number, followed optionally by a
+description, followed by the extension (C<.html> or C<.sh>). So to
+start our talk with two slides:
+
+ echo "This is the introduction" > 0010-introduction.html
+ echo "This is the second slide" > 0020-second.html
+
+To run it, run the command from within the talk directory:
+
+ techtalk-pse
+
+Any other file in the directory is ignored, so if you want to add
+Makefiles, version control files etc, just go ahead.
+
+=head2 TIPS FOR WRITING HTML
+
+You may have your own techniques and tools for writing HTML, so
+this section is just to share my ideas. I start every
+HTML file with a standard stylesheet and Javascript header:
+
+ <link rel="stylesheet" href="style.css" type="text/css"/>
+ <script src="code.js" type="text/javascript"></script>
+
+That just ensures that I can put common styling instructions for all
+my slides in a single file (C<style.css>), and I have one place where
+I can add all Javascript, if I need to use any (C<code.js>).
+
+=head3 BACKGROUNDS, FONTS AND LOGOS
+
+To add a common background and font size to all slides, put this in
+C<style.css>:
+
+ body {
+ font-size: 24pt;
+ background: url(background-image.jpg) no-repeat;
+ }
+
+To add a logo in one corner:
+
+ body {
+ background: url(logo.jpg) top right no-repeat;
+ }
+
+=head3 SCALING AND CENTERING
+
+Scaling slide text and images so that they appear at the same
+proportionate size for any screen resolution can be done using
+Javascript. (See
+L<https://developer.mozilla.org/En/DOM/window.innerHeight>).
+
+If you want to center text horizontally, use CSS, eg:
+
+ p.center {
+ text-align: center;
+ }
+
+To center text vertically, CSS3 is supposed to offer a solution some
+time, but while you're waiting for that try
+L<http://www.w3.org/Style/Examples/007/center#vertical>.
+
+=head3 PREVIEWING HTML
+
+I find it helpful to have Firefox open to display the HTML files and
+styles as I edit them. Just start firefox in the talk directory:
+
+ firefox file://$(pwd) &
+
+When you edit an HTML file, click the Firefox reload button to
+immediately see your changes.
+
+Tech Talk PSE uses Mozilla embedding to display HTML, which uses the
+same Mozilla engine as Firefox, so what you should see in Firefox
+should be identical to what Tech Talk PSE displays.
+
+=head2 CREATING FIGURES
+
+Use your favorite tool to draw the figure, convert it to an image (in
+any format that the Mozilla engine can display) and include it using
+an C<E<lt>imgE<gt>> tag, eg:
+
+ <img src="fig1.gif">
+
+Suitable tools include: XFig, GnuPlot, GraphViz, and many TeX tools
+such as PicTex and in particular TikZ.
+
+=head2 EMBEDDING VIDEOS, ANIMATIONS, ETC.
+
+Using HTML 5, embedding videos in the browser is easy. See:
+L<https://developer.mozilla.org/En/Using_audio_and_video_in_Firefox>
+
+For animations, you could try L<Haxe|http://haxe.org/> which has a
+Javascript back-end. There are many other possibilities.
+
+If you are B<sure> that the venue will have an internet connection,
+why not embed a YouTube video.
+
+=head2 DISPLAYING EXISTING WEB PAGES
+
+Obviously you could just have an HTML file that contains a redirect to
+the public web page:
+
+ <meta http-equiv="Refresh" content="0; url=http://www.example.com/">
+
+However if you want your talk to work offline, then it's better to
+download the web page in advance, eg. using Firefox's "Save Page As
+-E<gt> Web Page, complete" feature, into the talk directory, then
+either rename or make a symbolic link to the slide name:
+
+ ln -s "haXe - Welcome to haXe.html" 0010-haxe-homepage.html
+
+=head2 TIPS FOR WRITING SHELL SCRIPTS
+
+Make sure each C<*.sh> file you write is executable, otherwise Tech
+Talk PSE won't be able to run it. (The program gives a warning if you
+forget this).
+
+A good idea is to start each script by sourcing some common functions.
+All my scripts start with:
+
+ #!/bin/bash -
+ source functions
+
+where C<functions> is another file (ignored by Tech Talk PSE) which
+contains common functions for setting shell history and starting a
+terminal.
+
+In C<functions>, I have:
+
+ # -*- shell-script -*-
+ export PS1="$ "
+ export HISTFILE=/tmp/history
+ rm -f $HISTFILE
+
+ add_history ()
+ {
+ echo "$@" >> $HISTFILE
+ }
+
+ terminal ()
+ {
+ exec \
+ gnome-terminal \
+ --window \
+ --geometry=+100+100 \
+ --hide-menubar \
+ --disable-factory \
+ -e '/bin/bash --norc' \
+ "$@"
+ }
+
+By initializing the shell history, during your talk you can rapidly
+recall commands to start parts of the demonstration just by hitting
+the Up arrow. A complete shell script from one of my talks would look
+like this:
+
+ #!/bin/bash -
+ source functions
+ add_history guestfish -i debian.img
+ terminal --title="Examining a Debian guest image in guestfish"
+
+This is just a starting point for your own scripts. You may want to
+use a different terminal, such as xterm, and you may want to adjust
+terminal fonts.
+
=head1 REFERENCE
+=head2 ORDER OF FILES
+
+Tech Talk PSE displays the slides in the directory in lexicographic
+order (the same order as C<LANG=C ls -1>). Only files matching the
+following regexp are considered:
+
+ ^(\d+)(?:-.*)\.(html|sh)$
+
+For future compatibility, you should ensure that every slide has a
+unique numeric part (ie. I<don't> have C<0010-aaa.html> and
+C<0010-bbb.html>). This is because in future we want to have the
+ability to display multiple files side by side.
+
+Also for future compatibility, I<don't> use file names that have an
+uppercase letter immediately after the numeric part. This is because
+in future we want to allow placement hints using filenames like
+C<0010L-on-the-left.html> and C<0010R-on-the-right.html>.
+
+=head2 BASE URL AND CURRENT DIRECTORY
+
+The base URL is set to the be the directory containing the talk files.
+Thus you should use relative paths, eg:
+
+ <img src="fig1.gif">
+
+You can also place assets into subdirectories, because subdirectories
+are ignored by Tech Talk PSE, eg:
+
+ <img src="images/fig1.gif">
+
+When running shell scripts, the current directory is also set to be
+the directory containing the talk files, so the same rules about using
+relative paths apply there too.
+
+The environment variable C<$talkdir> is exported to scripts and it
+contains the absolute path of the directory containing the talk files.
+When a script is run, the current directory is the same as
+C<$talkdir>, but if your script changes directory (eg. into a
+subdirectory containing supporting files) then it can be useful to use
+C<$talkdir> to refer back to the original directory.
+
=head1 WHAT MAKES A GOOD TALK
+I like what Edward Tufte writes, for example his evisceration of
+PowerPoint use at NASA here:
+L<http://www.edwardtufte.com/bboard/q-and-a-fetch-msg?msg_id=0001yB>
+
+However it is sometimes hard to translate his ideas into clear
+presentations, and not all of that is the fault of the tools. Here
+are my thoughts and rules on how to deliver a good talk.
+
+B<First, most important rule:> Before you start drawing any slides at
+all, write your talk as a short essay.
+
+This is the number one mistake that presenters make, and it is partly
+a tool fault, because PowerPoint, OpenOffice, even Tech Talk PSE, all
+open up on an initial blank slide, inviting you to write a title and
+some bullet points. If you start that way, you will end up using the
+program as a kind of clumsy outlining tool, and then reading that
+outline to your audience. That's boring and a waste of time for you
+and your audience. (It would be quicker for them just to download the
+talk and read it at home).
+
+B<Secondly:> How long do you want to spend preparing the talk? A good
+talk, with a sound essay behind it, well thought out diagrams and
+figures, and interesting demonstrations, takes many hours to prepare.
+How many hours? I would suggest thinking about how many hours of
+effort your audience are putting in. Even just 20 people sitting
+there for half an hour is 10 man-hours of attention, and that is a
+very small talk, and doesn't include all the extra time and hassle
+that it took to get them all in one place.
+
+I don't think you can get away with spending less than two full days
+preparing a talk, if you want to master the topic and draw up accurate
+slides. Steve Jobs is reputed to spend weeks preparing his annual
+sales talk to the Apple faithful.
+
+B<Thirdly:> Now that you're going to write your talk as an essay, what
+should go in the slides? I would say that you should consider
+delivering the essay, I<not> the slides, to people who don't make the
+talk. An essay can be turned into an article or blog posting, whereas
+even "read-out-the-bullet-point" slides have a low information
+density, large size, and end-user compatibility problems (*.pptx
+anyone?).
+
+What, then, goes on the slides? Anything you cannot just say:
+diagrams, graphs, videos, animations, and of course (only with Tech
+Talk PSE!) demonstrations.
+
+B<Lastly:> Once you've got your talk as an essay and slides, practice,
+practice and practice again. Deliver the talk to yourself in the
+mirror, to your colleagues. Practice going backwards and forwards
+through the slides, using your actual laptop and the software so you
+know what to click and what keys to press. Partly memorize what you
+are going to say (but use short notes written on paper if you need
+to).
+
=head1 SEE ALSO
The Cognitive Style of PowerPoint, Tufte, Edward R.