* Add a graphviz plugin.

* Suggests: graphviz

1 files changed, 86 insertions, 0 deletions

diff --git a/IkiWiki/Plugin/graphviz.pm b/IkiWiki/Plugin/graphviz.pm
new file mode 100644
index 000000000..48f520c4f
--- /dev/null
+++ b/IkiWiki/Plugin/graphviz.pm
@@ -0,0 +1,86 @@
+#!/usr/bin/perl
+# graphviz plugin for ikiwiki: render graphviz source as an image.
+# Josh Triplett
+package IkiWiki::Plugin::graphviz;
+
+use warnings;
+use strict;
+use IkiWiki;
+use IPC::Open2;
+
+sub import { #{{{
+	hook(type => "preprocess", id => "graph", call => \&graph);
+} # }}}
+
+my %graphviz_programs = (
+	"dot" => 1, "neato" => 1, "fdp" => 1, "twopi" => 1, "circo" => 1
+);
+
+sub render_graph (\%) { #{{{
+	my %params = %{(shift)};
+
+	my $src = "$params{type} g {\n";
+	$src .= "charset=\"utf-8\";\n";
+	$src .= "ratio=compress;\nsize=\"".($params{width}+0).", ".($params{height}+0)."\";\n"
+		if defined $params{width} and defined $params{height};
+	$src .= $params{src};
+	$src .= "}\n";
+
+	# Use the sha1 of the graphviz code as part of its filename.
+	eval q{use Digest::SHA1};
+	error($@) if $@;
+	my $dest=$params{page}."/graph-".
+		IkiWiki::possibly_foolish_untaint(Digest::SHA1::sha1_hex($src)).
+		".png";
+	will_render($params{page}, $dest);
+
+	if (! -e "$config{destdir}/$dest") {
+		my $pid;
+		my $sigpipe=0;;
+		$SIG{PIPE}=sub { $sigpipe=1 };
+		$pid=open2(*IN, *OUT, "$params{prog} -Tpng");
+
+		# open2 doesn't respect "use open ':utf8'"
+		binmode (IN, ':utf8');
+		binmode (OUT, ':utf8');
+
+		print OUT $src;
+		close OUT;
+
+		my $png;
+		{
+			local $/ = undef;
+			$png = <IN>;
+		}
+		close IN;
+
+		waitpid $pid, 0;
+		$SIG{PIPE}="DEFAULT";
+		return  "[[graph ".gettext("failed to run graphviz")."]]" if ($sigpipe);
+
+		if (! $params{preview}) {
+			writefile($dest, $config{destdir}, $png, 1);
+		}
+		else {
+			# can't write the file, so embed it in a data uri
+			eval q{use MIME::Base64};
+			error($@) if $@;
+			return "<img src=\"data:image/png;base64,".
+				encode_base64($png)."\" />";
+		}
+	}
+
+	return "<img src=\"".urlto($dest, $params{page})."\" />\n";
+} #}}}
+
+sub graph (@) { #{{{
+	my %params=@_;
+	$params{src} = "" unless defined $params{src};
+	$params{type} = "digraph" unless defined $params{type};
+	$params{prog} = "dot" unless defined $params{prog};
+	return "[[graph ".gettext("prog not a valid graphviz program")."]]" unless $graphviz_programs{$params{prog}};
+
+	return render_graph(%params);
+} # }}}
+
+1