feat: add support for SVG logo format + fix logo URL in JSONLD

Can now upload an SVG logo to `assets/images/logo.svg`.

If your site is for an organization, Google currently requires that the logo is PNG rather than SVG otherwise the site may not receive rich search results based on the JSONLD (see https://developers.google.com/search/docs/data-types/logo).

Also, this commit fixes the logo URL in the site's JSONLD metadata - irrespective of the above feature, the logo URL metadata broke when adding the new automated logo detection system in #1439.

Close #1512
Fix #1516
Fix #1439

layouts/partials/functions/get_logo.html

@@ -2,15 +2,20 @@
 {{/* Inputs: constraint: max_height/fit (str); size (int) */}}
 {{/* Output: resource (obj) */}}
 
-{{ $logo := resources.Get "images/logo.png" }}
+{{/* Workaround fact Hugo does not support GetMatch in assets dir */}}
+{{/* Hugo doesn't support image ops on SVG: https://discourse.gohugo.io/t/ho-do-i-convert-a-generic-resource-to-image-resource/22570/4 */}}
+{{ $logo := resources.Get "images/logo.png" | default (resources.Get "images/logo.svg") }}
 {{ $logo_proc := $logo }}
 
-{{ if eq .constraint "max_height" }}
-  {{/* Resize logo to fit specified max height. */}}
-  {{ $logo_proc = ($logo.Resize (printf "x%s" (string .size))) }}
-{{ else }}
-  {{/* Constrain logo to fit within specified dimensions. */}}
-  {{ $logo_proc = ($logo.Fit (printf "%sx%s" (string .size) (string .size))) }}
+{{/* If the type of image can be resized by Hugo, resize it given a `.size` argument to the function. */}}
+{{ if resources.Get "images/logo.png" }}
+  {{ if eq .constraint "max_height" }}
+    {{/* Resize logo to fit specified max height. */}}
+    {{ $logo_proc = ($logo.Resize (printf "x%s" (string .size))) }}
+  {{ else }}
+    {{/* Constrain logo to fit within specified dimensions. */}}
+    {{ $logo_proc = ($logo.Fit (printf "%sx%s" (string .size) (string .size))) }}
+  {{ end }}
 {{ end }}
 
 {{ return $logo_proc }}

layouts/partials/functions/get_logo_url.html

@@ -0,0 +1,12 @@
+{{/* Function to get logo URL for JSONLD. */}}
+{{/* Inputs: page context */}}
+{{/* Output: logo URL (URL) */}}
+
+{{ $logo_url := "" }}
+{{ if resources.Get "images/logo.png" | or (resources.Get "images/logo.svg") }}
+  {{ $logo_url = (partial "functions/get_logo" (dict "constraint" "fit" "size" 192)).Permalink }}
+{{ else }}
+  {{ $logo_url = (partial "functions/get_icon" 192).Permalink }}
+{{ end }}
+
+{{ return $logo_url }}

layouts/partials/jsonld/article.html

@@ -1,4 +1,4 @@
-{{ $page := .page }}
+{{- $page := .page }}
 {{ $summary := .summary }}
 {{ $featured_image := ($page.Resources.ByType "image").GetMatch "*featured*" }}
 
@@ -10,7 +10,7 @@
 
 {{ $author := partial "functions/get_author_name" $page }}
 {{ $publisher := site.Params.org_name | default site.Title }}
-{{ $logo_url := (printf "img/%s" (site.Params.logo | absURL)) | default (partial "functions/get_icon" 512).Permalink }}
+{{ $logo_url := partial "functions/get_logo_url" $page -}}
 
 <script type="application/ld+json">
 {

layouts/partials/jsonld/business.html

@@ -4,7 +4,7 @@
   "@type": {{site.Params.local_business_type | default site.Params.site_type}},
   "@id": {{site.BaseURL}},
   "name": {{site.Params.org_name | default site.Title}},
-  {{with site.Params.logo}}"logo": {{printf "img/%s" . | absURL}},{{end}}
+  "logo": {{ partial "functions/get_logo_url" . }},
   {{with site.Params.sharing_image}}"image": {{printf "img/%s" . | absURL}},{{end}}
   {{ if (eq site.Params.site_type "LocalBusiness") | and site.Params.coordinates }}
   "geo": {

layouts/partials/navbar.html

@@ -2,7 +2,7 @@
 
 {{/* Get site logo. */}}
 {{ $show_logo := site.Params.main_menu.show_logo | default true }}
-{{ $has_logo := fileExists "assets/images/logo.png" }}
+{{ $has_logo := fileExists "assets/images/logo.png" | or (fileExists "assets/images/logo.svg") }}
 {{ $logo := "" }}
 {{ if $has_logo }}
   {{ $logo = (partial "functions/get_logo" (dict "constraint" "max_height" "size" 70)) }}

layouts/partials/site_head.html

@@ -148,7 +148,7 @@
   <link rel="canonical" href="{{ .Permalink }}">
 
   {{ $featured_image := (.Resources.ByType "image").GetMatch "*featured*" }}
-  {{ $has_logo := fileExists "assets/images/logo.png" }}
+  {{ $has_logo := fileExists "assets/images/logo.png" | or (fileExists "assets/images/logo.svg") }}
   {{ $og_image := "" }}
   {{ $twitter_card := "summary_large_image" }}
   {{ if $featured_image }}