[wip] m.dot: support node and edge links.

TODO: there's a separate <g id="a_edge1&#45;label"> for the edge
label which should be removed and replaced with just <g>
TODO: update test files for graphviz 2:36 and 2.38 (ugh)

Author: mosra

plugins/dot2svg.py

@@ -43,11 +43,21 @@
 _class_src = re.compile(r"""<g id="(edge|node|clust)\d+" class="(?P<type>edge|node|cluster)(?P<classes>[^"]*)">
 <title>(?P<title>[^<]*)</title>
 <(?P<element>ellipse|polygon|path|text)( fill="(?P<fill>[^"]+)" stroke="[^"]+")? """)
-
 _class_dst = r"""<g class="{classes}">
 <title>{title}</title>
 <{element} """
 
+# Nodes that are links have an additional group containing a link inside. Again
+# Graphviz < 2.40 (Ubuntu 16.04 and older) doesn't have a linebreak between <g>
+# and <title>.
+_class_with_link_inside_src = re.compile(r"""<g id="(edge|node)\d+" class="(?P<type>edge|node)(?P<classes>[^"]*)">[\n]?<title>(?P<title>[^<]*)</title>
+<g id="a_(edge|node)\d+"><a (?P<link>[^>]+)>
+<(?P<element>ellipse|polygon|path) fill="(?P<fill>[^"]+)" stroke="[^"]+" """)
+_class_with_link_inside_dst = r"""<g class="{classes}">
+<title>{title}</title>
+<g><a {link}>
+<{element} """
+
 _attributes_src = re.compile(r"""<(?P<element>ellipse|polygon|polyline) fill="[^"]+" stroke="[^"]+" """)
 
 _attributes_dst = r"""<\g<element> """
@@ -111,6 +121,20 @@ def element_repl(match):
             element=match.group('element'))
     svg = _class_src.sub(element_repl, svg)
 
+    # Links have additional group around, second pass with a different regex
+    def element_link_repl(match):
+        classes = ['m-' + match.group('type')] + match.group('classes').replace('&#45;', '-').split()
+        # distinguish between solid and filled nodes
+        if match.group('type') == 'node' and match.group('fill') == 'none':
+            classes += ['m-flat']
+
+        return _class_with_link_inside_dst.format(
+            link=match.group('link'),
+            classes=' '.join(classes),
+            title=match.group('title'),
+            element=match.group('element'))
+    svg = _class_with_link_inside_src.sub(element_link_repl, svg)
+
     # Remove unnecessary fill and stroke attributes
     svg = _attributes_src.sub(_attributes_dst, svg)
 

plugins/m/test/dot/page-240.html

@@ -59,6 +59,17 @@ Structs:
 
     another [label="a | { b | c } | d | e" shape=record]
 
+Links:
+
+.. digraph::
+
+    A [label="link to #" URL="#" style=filled class="m-primary"]
+    B [label="link to /" URL="#" class="m-success"]
+
+    A -> B [label="link to m.css" URL="http://mcss.mosra.cz/" class="m-warning"]
+
+Figures:
+
 .. graph-figure:: This is a title.
 
     .. digraph:: A to B