From 44caa96dc5c16cbc4ee1bb26ec880af2e2ecf9f8 Mon Sep 17 00:00:00 2001
From: Lars Magne Ingebrigtsen <larsi@gnus.org>
Date: Mon, 27 Jun 2016 18:20:48 +0200
Subject: [PATCH] Add a new function `svg-embed'

* doc/lispref/display.texi (SVG Images): Document `svg-embed'.

* lisp/svg.el (svg-embed): New function.
(svg--image-data): Ditto.
---
 doc/lispref/display.texi | 13 +++++++++++++
 lisp/svg.el              | 23 +++++++++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/doc/lispref/display.texi b/doc/lispref/display.texi
index a7c1d0992de..575cad89f83 100644
--- a/doc/lispref/display.texi
+++ b/doc/lispref/display.texi
@@ -5350,6 +5350,19 @@ that describe the outer circumference of the polygon.
 @end lisp
 @end defun
 
+@defun svg-embed svg image image-type datap &rest args
+Add an embedded (raster) image to @var{svg}.  If @var{datap} is
+@code{nil}, @var{IMAGE} should be a file name; if not, it should be a
+binary string containing the image data.  @var{image-type} should be a
+@acronym{MIME} image type, for instance @samp{"image/jpeg"}.
+
+@lisp
+(svg-embed svg "~/rms.jpg" "image/jpeg" nil
+           :width "100px" :height "100px"
+           :x "50px" :y "75px")
+@end lisp
+@end defun
+
 Finally, the @code{svg-image} takes an SVG object as its parameter and
 returns an image object suitable for use in functions like
 @code{insert-image}.  Here's a complete example that creates and
diff --git a/lisp/svg.el b/lisp/svg.el
index c4f3270ea8a..c33b0923c26 100644
--- a/lisp/svg.el
+++ b/lisp/svg.el
@@ -137,6 +137,18 @@ POINTS is a list of x/y pairs."
 			    ", "))
       ,@(svg--arguments svg args)))))
 
+(defun svg-embed (svg image image-type datap &rest args)
+  "Insert IMAGE into the SVG structure.
+IMAGE should be a file name if DATAP is nil, and a binary string
+otherwise.  IMAGE-TYPE should be a MIME image type, like
+\"image/jpeg\" or the like."
+  (svg--append
+   svg
+   (dom-node
+    'image
+    `((xlink:href . ,(svg--image-data image image-type datap))
+      ,@(svg--arguments svg args)))))
+
 (defun svg--append (svg node)
   (let ((old (and (dom-attr node 'id)
 		  (dom-by-id svg
@@ -147,6 +159,17 @@ POINTS is a list of x/y pairs."
       (dom-append-child svg node)))
   (svg-possibly-update-image svg))
 
+(defun svg--image-data (image image-type datap)
+  (with-temp-buffer
+    (set-buffer-multibyte nil)
+    (if datap
+        (insert image)
+      (insert-file-contents image))
+    (base64-encode-region (point-min) (point-max) t)
+    (goto-char (point-min))
+    (insert "data:" image-type ";base64,")
+    (buffer-string)))
+
 (defun svg--arguments (svg args)
   (let ((stroke-width (or (plist-get args :stroke-width)
 			  (dom-attr svg 'stroke-width)))
-- 
2.11.4.GIT