Re: Loading svg from memory using custom filename for base_uri

[Evgeny Zajcev <lg.zevlg@gmail.com>]

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чт, 3 дек. 2020 г. в 22:57, Alan Third <alan@idiocy.org>:

> On Thu, Dec 03, 2020 at 08:50:15PM +0300, Evgeny Zajcev wrote:
> >
> > Here is updated patch, with support for `:base-uri` for :file image spec
> as
> > well
>
> It looks good to me. There are two things I think we need. One is to
> add an entry for :base-uri to the svg_format array in image.c,

done!

and
> some documentation, if you fancy writing it?
>
> Documentation better to write when `svg-embed` will support this feature.

Do we also need an entry in NEWS for this?
>

Added

-- 
lg

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From 230359a4bd7ca75a28441f7e5fae6ef1440a8c1b Mon Sep 17 00:00:00 2001
From: Zajcev Evgeny <zevlg@yandex.ru>
Date: Thu, 3 Dec 2020 18:37:18 +0300
Subject: [PATCH] Explicitly specify svg base_uri using `:base-uri' image
 property

* src/image.c (svg_load): Check `:base-uri' image property to
  explicitly set base_uri for images embedded into SVG
---
 etc/NEWS    |  6 ++++++
 src/image.c | 20 +++++++++++++-------
 2 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/etc/NEWS b/etc/NEWS
index 2fb33e342e..493e456c6c 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -24,6 +24,12 @@ applies, and please also update docstrings as needed.
 \f
 * Installation Changes in Emacs 28.1
 
+---
+** Can explicitly specify base_uri for svg images.
+':base-uri' image property can be used to explicitly specify base_uri
+for embedded images into svg. ':base-uri' is supported for both file
+and data svg images.
+
 ** Cairo graphics library is now used by default if found.
 '--with-cairo' is now the default, if the appropriate development files
 are found by 'configure'.  Note that building with Cairo means using
diff --git a/src/image.c b/src/image.c
index 5eb4132295..89ebc60c6c 100644
--- a/src/image.c
+++ b/src/image.c
@@ -9472,6 +9472,7 @@ DEFUN ("imagemagick-types", Fimagemagick_types, Simagemagick_types, 0, 0, 0,
   {":type",		IMAGE_SYMBOL_VALUE,			1},
   {":data",		IMAGE_STRING_VALUE,			0},
   {":file",		IMAGE_STRING_VALUE,			0},
+  {":base-uri",		IMAGE_STRING_VALUE,			0},
   {":ascent",		IMAGE_ASCENT_VALUE,			0},
   {":margin",		IMAGE_NON_NEGATIVE_INTEGER_VALUE_OR_PAIR, 0},
   {":relief",		IMAGE_INTEGER_VALUE,			0},
@@ -9698,10 +9699,11 @@ init_svg_functions (void)
 svg_load (struct frame *f, struct image *img)
 {
   bool success_p = 0;
-  Lisp_Object file_name;
+  Lisp_Object file_name, base_uri;
 
   /* If IMG->spec specifies a file name, create a non-file spec from it.  */
   file_name = image_spec_value (img->spec, QCfile, NULL);
+  base_uri = image_spec_value (img->spec, QCbase_uri, NULL);
   if (STRINGP (file_name))
     {
       int fd;
@@ -9721,15 +9723,16 @@ svg_load (struct frame *f, struct image *img)
 	  return 0;
 	}
       /* If the file was slurped into memory properly, parse it.  */
-      success_p = svg_load_image (f, img, contents, size,
-				  SSDATA (ENCODE_FILE (file)));
+      if (!STRINGP (base_uri))
+        base_uri = ENCODE_FILE (file);
+      success_p = svg_load_image (f, img, contents, size, SSDATA (base_uri));
       xfree (contents);
     }
   /* Else it's not a file, it's a Lisp object.  Load the image from a
      Lisp object rather than a file.  */
   else
     {
-      Lisp_Object data, original_filename;
+      Lisp_Object data;
 
       data = image_spec_value (img->spec, QCdata, NULL);
       if (!STRINGP (data))
@@ -9737,10 +9740,10 @@ svg_load (struct frame *f, struct image *img)
 	  image_error ("Invalid image data `%s'", data);
 	  return 0;
 	}
-      original_filename = BVAR (current_buffer, filename);
+      if (!STRINGP (base_uri))
+        base_uri = BVAR (current_buffer, filename);
       success_p = svg_load_image (f, img, SSDATA (data), SBYTES (data),
-                                  (NILP (original_filename) ? NULL
-				   : SSDATA (original_filename)));
+                                  (NILP (base_uri) ? NULL : SSDATA (base_uri)));
     }
 
   return success_p;
@@ -9838,6 +9841,7 @@ svg_load_image (struct frame *f, struct image *img, char *contents,
   eassume (rsvg_handle);
 
   /* Set base_uri for properly handling referenced images (via 'href').
+     Can be explicitly specified using `:base_uri' image property.
      See rsvg bug 596114 - "image refs are relative to curdir, not .svg file"
      <https://gitlab.gnome.org/GNOME/librsvg/issues/33>. */
   if (filename)
@@ -10002,6 +10006,7 @@ svg_load_image (struct frame *f, struct image *img, char *contents,
   eassume (rsvg_handle);
 
   /* Set base_uri for properly handling referenced images (via 'href').
+     Can be explicitly specified using `:base_uri' image property.
      See rsvg bug 596114 - "image refs are relative to curdir, not .svg file"
      <https://gitlab.gnome.org/GNOME/librsvg/issues/33>. */
   if (filename)
@@ -10684,6 +10689,7 @@ syms_of_image (void)
 
 #if defined (HAVE_RSVG)
   DEFSYM (Qsvg, "svg");
+  DEFSYM (QCbase_uri, ":base-uri");
   add_image_type (Qsvg);
 #ifdef HAVE_NTGUI
   /* Other libraries used directly by svg code.  */
-- 
2.25.1