Add open-graph tags support

build.sbt

@@ -42,6 +42,13 @@ lazy val root = project("paradox-material-theme-parent", file("."))
     }
     // #social
     ,
+    // #open-graph
+    Compile / paradoxProperties ++= Map(
+      "project.description" -> "Paradox Material Theme is a theme for Paradox, a static site generator geared towards project documentation",
+      "project.image" -> "https://www.scala-sbt.org/sbt-paradox-material-theme/images/material.png"
+    )
+    // #open-graph
+    ,
     // #language
     Compile / paradoxMaterialTheme ~= {
       _.withLanguage(java.util.Locale.ENGLISH)

src/main/paradox/getting-started.md

@@ -225,6 +225,12 @@ on the URL:
 
   [17]: http://fontawesome.io/icons/
 
+## Open graph metadata
+To enable a nice preview of the site in social media, define the
+following properties in the build:
+
+@@ snip [build.sbt]($root$/build.sbt) { #open-graph }
+
 ## Copyright Notice
 
 To display a copyright notice in the footer configure the

theme/src/main/assets/page.st

@@ -27,6 +27,15 @@ $!
     <meta name="viewport" content="width=device-width,initial-scale=1">
     <meta http-equiv="x-ua-compatible" content="ie=edge">
     <meta name="description" content="$page.properties.("project.description")$">
+    $ if (page.properties.("title")) $
+        <meta property="og:title" content="$page.properties.("title")$">
+    $ endif $
+    $ if (page.properties.("project.description")) $
+        <meta property="og:description" content="$page.properties.("project.description")$">
+    $ endif $
+    $ if (page.properties.("project.image")) $
+        <meta property="og:image" content="$page.properties.("project.image")$">
+    $ endif $
     <meta name="generator" content="Paradox, paradox-material-theme=$page.properties.("material.theme.version")$, mkdocs-material=3.0.3">
 
     $partials/language()$