comments: add avatar picture of comment author

Use Libravatar::URL to pull the avatar picture for the comment
author if we have an email address for him/her.

IkiWiki/Plugin/comments.pm

@@ -167,6 +167,7 @@ sub preprocess {
 	my $commentip;
 	my $commentauthor;
 	my $commentauthorurl;
+	my $commentauthoravatar;
 	my $commentopenid;
 	if (defined $params{username}) {
 		$commentuser = $params{username};
@@ -187,6 +188,16 @@ sub preprocess {
 
 			$commentauthor = $commentuser;
 		}
+
+                eval 'use Libravatar::URL';
+
+                if (! $@) {
+                    my $email = IkiWiki::userinfo_get($commentuser, 'email');
+
+                    if (defined $email) {
+                        $commentauthoravatar = libravatar_url(email => $email);
+                    }
+                }
 	}
 	else {
 		if (defined $params{ip}) {
@@ -200,6 +211,7 @@ sub preprocess {
 	$commentstate{$page}{commentip} = $commentip;
 	$commentstate{$page}{commentauthor} = $commentauthor;
 	$commentstate{$page}{commentauthorurl} = $commentauthorurl;
+	$commentstate{$page}{commentauthoravatar} = $commentauthoravatar;
 	if (! defined $pagestate{$page}{meta}{author}) {
 		$pagestate{$page}{meta}{author} = $commentauthor;
 	}
@@ -874,6 +886,11 @@ sub pagetemplate (@) {
 			$commentstate{$page}{commentauthorurl});
 	}
 
+	if ($template->query(name => 'commentauthoravatar')) {
+		$template->param(commentauthoravatar =>
+			$commentstate{$page}{commentauthoravatar});
+	}
+
 	if ($template->query(name => 'removeurl') &&
 	    IkiWiki::Plugin::remove->can("check_canremove") &&
 	    length $config{cgiurl}) {

doc/style.css

@@ -247,6 +247,9 @@ span.color {
 .comment-subject {
 	font-weight: bold;
 }
+.comment-avatar {
+	float: right;
+}
 .comment {
 	border: 1px solid #aaa;
 	padding: 3px;

templates/comment.tmpl

@@ -1,6 +1,10 @@
 <TMPL_IF HTML5><article class="comment" id="<TMPL_VAR COMMENTID>">
 <TMPL_ELSE><div class="comment" id="<TMPL_VAR COMMENTID>"></TMPL_IF>
 
+<TMPL_IF COMMENTAUTHORAVATAR><div class="comment-avatar">
+<img src="<TMPL_VAR COMMENTAUTHORAVATAR>" alt="" />
+</div></TMPL_IF>
+
 <TMPL_IF HTML5><header class="comment-subject"><TMPL_ELSE><div class="comment-subject"></TMPL_IF>
 <TMPL_IF PERMALINK>
 <a href="<TMPL_VAR PERMALINK>"><TMPL_VAR TITLE></a>
@@ -58,4 +62,5 @@ Comment by
 <TMPL_IF HTML5></nav><TMPL_ELSE></div></TMPL_IF>
 </TMPL_IF>
 
+<div style="clear: both"></div>
 <TMPL_IF HTML5></article><TMPL_ELSE></div></TMPL_IF>