From 1b37c53095bb46844910ce3f0b699ea9a0b152d8 Mon Sep 17 00:00:00 2001
From: Mischa POSLAWSKY <perl@shiar.org>
Date: Fri, 9 Apr 2021 06:29:03 +0200
Subject: [PATCH] widget/reply: lazy image loading in html5

Indicate BTF images are optional (assume the first two are visible),
to reduce bandwidth for quick peeks.

Supported in FF 75+ and Chrome 77+ (no Safari yet) but not important enough
to bother with javascript complexity.
---
 widget/reply.php | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/widget/reply.php b/widget/reply.php
index 0a0e4e5..4da0ffa 100644
--- a/widget/reply.php
+++ b/widget/reply.php
@@ -86,13 +86,19 @@ $query = $Db->query("SELECT $cols FROM comments WHERE page = ? ORDER BY created"
 
 print '<ul class="replies">';
 
+$imagecount = 0;
 while ($row = $query->fetch()) {
 	$rowuser = new User("profile/{$row->author}");
 	printf('<li id="%d">', $row->id);
 	printf('<strong>%s</strong> <small class=date>%s</small>',
 		$rowuser->html, showdate(preg_split('/\D/', $row->created))
 	);
-	printf("<blockquote>\n%s</blockquote>\n", $row->message);
+	if ($html = $row->message) {
+		$html = preg_replace('/(?<=<img )/',
+			$imagecount > 2 ? 'loading="lazy" ' : '', $html, -1, $found);
+		$imagecount += $found;
+		printf("<blockquote>\n%s</blockquote>\n", $html);
+	}
 	if ($changes = json_decode($row->journal)) {
 		print '<ul>';
 		foreach ($changes as $change) {
-- 
2.30.0