1 file changed, 11 insertions, 7 deletions
diff --git a/custom/extensions/email-libravatar.lua b/custom/extensions/email-libravatar.lua
index e04c2c2..cc726de 100644
--- a/custom/extensions/email-libravatar.lua
+++ b/custom/extensions/email-libravatar.lua
@@ -34,10 +34,11 @@
 local has_digest, digest = pcall(require, "openssl.digest")
 
 
--- The size is in pixels and serves both as the image asked of the service
--- and as the width and height attributes. The default image is what
--- Libravatar draws for an address it has never seen. The endpoint is the
--- secure CDN so the icon is not blocked as mixed content on an https page.
+-- The size is in pixels and serves both as the image asked of the service and
+-- as the width and height attributes, while a screen of double density is
+-- offered an image twice the size. The default image is what Libravatar draws
+-- for an address it has never seen. The endpoint is the secure CDN so the icon
+-- is not blocked as mixed content on an https page.
 local avatar_size = 13
 local default_image = "retro"
 local base_url = "https://seccdn.libravatar.org/avatar/"
@@ -107,6 +108,10 @@ function filter_write(text)
 	buffer = buffer .. text
 end
 
+local function avatar_url(size)
+	return base_url .. avatar_hash .. "?s=" .. size .. "&amp;d=" .. default_image
+end
+
 -- A log page can carry one icon per commit, so the attributes let the
 -- browser defer the fetches for icons still off screen and keep decoding
 -- off the critical path. The icon only decorates the name beside it, so its
@@ -115,9 +120,8 @@ function filter_close()
 	if avatar_hash == nil then
 		html(buffer)
 	else
-		html("<img src='" .. base_url .. avatar_hash ..
-			"?s=" .. avatar_size ..
-			"&amp;d=" .. default_image ..
+		html("<img src='" .. avatar_url(avatar_size) ..
+			"' srcset='" .. avatar_url(avatar_size * 2) .. " 2x" ..
 			"' alt='' width='" .. avatar_size ..
 			"' height='" .. avatar_size ..
 			"' loading='lazy' decoding='async'> " .. buffer)