Embed SVGs when exporting Org-Roam

Signed-off-by: Magic_RB <magic_rb@redalder.org>

emacs-lisp/org_roam.org

@@ -126,25 +126,61 @@ Lastly a bookmarklet in Firefox.
 #+begin_src emacs-lisp :tangle no :results none
   (require 'org-roam-export)
 
+  (require 'nxml-mode)
+
   (defun magic_rb/org-html-publish-to-html-continue (plist filename pub-dir)
     (org-html-publish-to-html plist filename pub-dir))
 
-  (setq org-publish-project-alist
-          `(("org"
-             :base-directory "~/roam/"
-             :publishing-function org-html-publish-to-html ;; magic_rb/org-html-publish-to-html-continue
-             :publishing-directory "~/roam/published"
-             :exclude "^.*$"
-             :include ,(seq-map #'car
-                                (org-roam-db-query
-                                 [:select [nodes:file]
-                                          :from tags
-                                          :left-join nodes
-                                          :on (= tags:node-id nodes:id)
-                                          :where (like tag (quote "%\"public-publish\""))]))
-             )))
+  (defcustom org+-html-embed-svg nil
+    "Embed SVG images.
+    You can set this variable in Org files with
+    ,#+HTML_EMBED_SVG: t
+    or
+    ,#+OPTIONS: html-embed-svg:t"
+    :type 'boolean
+    :group 'org-export-html)
 
-        (org-publish "org" t)
+  (cl-pushnew
+   '(:html-embed-svg "HTML_EMBED_SVG" "html-embed-svg" org+-html-embed-svg)
+   (org-export-backend-options (org-export-get-backend 'html)))
+
+  (defun org+-html-svg-image-embed (fun source attributes info)
+    "Make embedding of SVG images possible in org HTML export.
+    SVG images are embedded if :html-embed-svg is non-nil in the plist INFO.
+    Otherwise FUN called with SOURCE, ATTRIBUTES, and INFO as arguments.
+    SOURCE is the file name of the SVG file.
+    This is an around advice for `org-html--svg-image' as FUN."
+    (if (and
+         (member (plist-get info :html-embed-svg) '("yes" "t" t))
+         (string-equal "svg" (file-name-extension source)))
+        (with-temp-buffer
+          (message "embedding svg: %s" source)
+          (insert-file-contents source)
+          (with-syntax-table nxml-mode-syntax-table
+            (while (and (search-forward "<svg") ;; barfs if a "<svg" is not found in code
+                        (nth 8 (syntax-ppss)))))
+          (delete-region (point-min) (match-beginning 0))
+          (buffer-string))
+      (funcall fun (concat "../" source) attributes info)))
+
+  (advice-add 'org-html--format-image :around #'org+-html-svg-image-embed)
+
+  (setq org-publish-project-alist
+        `(("org"
+           :base-directory "~/roam/"
+           :publishing-function org-html-publish-to-html ;; magic_rb/org-html-publish-to-html-continue
+           :publishing-directory "~/roam/published"
+           :exclude "^.*$"
+           :include ,(seq-map #'car
+                              (org-roam-db-query
+                               [:select [nodes:file]
+                                        :from tags
+                                        :left-join nodes
+                                        :on (= tags:node-id nodes:id)
+                                        :where (like tag (quote "%\"public-publish\""))]))
+           )))
+
+  (org-publish "org" t)
 #+end_src
 
 https://emacs.stackexchange.com/questions/59149/why-is-latex-preview-and-latex-to-html-export-via-dvisvgm-not-working-in-org-mod