Remove custom SVG processing in the HTML builder (#12425)

Co-authored-by: Adam Turner <9087854+aa-turner@users.noreply.github.com>

CHANGES.rst

@@ -94,6 +94,9 @@ Bugs fixed
 * #11961: Omit anchor references from document title entries in the search index,
   removing duplication of search results.
   Patch by James Addison.
+* #12425: Use Docutils' SVG processing in the HTML builder
+  and remove Sphinx's custom logic.
+  Patch by Tunç Başar Köse.
 
 Testing
 -------

sphinx/writers/html5.py

@@ -696,24 +696,6 @@ class HTML5Translator(SphinxTranslator, BaseTranslator):
                     if 'height' not in node:
                         node['height'] = str(size[1])
 
-        uri = node['uri']
-        if uri.lower().endswith(('svg', 'svgz')):
-            atts = {'src': uri}
-            if 'width' in node:
-                atts['width'] = node['width']
-            if 'height' in node:
-                atts['height'] = node['height']
-            if 'scale' in node:
-                if 'width' in atts:
-                    atts['width'] = multiply_length(atts['width'], node['scale'])
-                if 'height' in atts:
-                    atts['height'] = multiply_length(atts['height'], node['scale'])
-            atts['alt'] = node.get('alt', uri)
-            if 'align' in node:
-                atts['class'] = 'align-%s' % node['align']
-            self.body.append(self.emptytag(node, 'img', '', **atts))
-            return
-
         super().visit_image(node)
 
     # overwritten

tests/roots/test-root/images.txt

@@ -18,5 +18,13 @@ Sphinx image handling
 .. an SVG image (for HTML at least)
 .. image:: svgimg.*
 
+.. an SVG image using width with units
+.. image:: svgimg.*
+   :width: 2cm
+
+.. an SVG image using height with units
+.. image:: svgimg.*
+   :height: 2cm
+
 .. an image with more than 1 dot in its file name
 .. image:: img.foo.png

tests/test_builders/test_build_html_5_output.py

@@ -25,6 +25,9 @@ def tail_check(check):
     ('images.html', ".//img[@src='_images/simg.png']", ''),
     ('images.html', ".//img[@src='_images/svgimg.svg']", ''),
     ('images.html', ".//a[@href='_sources/images.txt']", ''),
+    # Check svg options
+    ('images.html', ".//img[@src='_images/svgimg.svg'][@style='width: 2cm;']", ''),
+    ('images.html', ".//img[@src='_images/svgimg.svg'][@style='height: 2cm;']", ''),
 
     ('subdir/images.html', ".//img[@src='../_images/img1.png']", ''),
     ('subdir/images.html', ".//img[@src='../_images/rimg.png']", ''),