Fix removing unused chained references. Added another test case.

scour.py

@@ -105,6 +105,8 @@ def findElementsWithId(node,elems={}):
 # returns the number of times an id is referenced
 # currently looks at fill, stroke and xlink:href attributes
 def findReferencedElements(node,ids={}):
+	# TODO: error here (ids is not cleared upon next invocation), the
+	# input argument ids is clunky here (see below how it is called)
 	href = node.getAttributeNS(XLINKNS,'href')
 	
 	# if xlink:href is set, then grab the id
@@ -169,14 +171,14 @@ def vacuumDefs(doc):
 		for elem in aDef.childNodes:
 			if( elem.nodeType == 1 and elem.getAttribute('id') == '' ):
 				aDef.removeChild(elem)
-				numElemsRemoved += 
+				numElemsRemoved += 1
 				num += 1
 	return num
 
 bContinueLooping = True
 while bContinueLooping:
-	identifiedElements = findElementsWithId(doc.documentElement)
-	referencedIDs = findReferencedElements(doc.documentElement)
+	identifiedElements = findElementsWithId(doc.documentElement, {})
+	referencedIDs = findReferencedElements(doc.documentElement, {})
 	bContinueLooping = ((removeUnreferencedIDs(referencedIDs, identifiedElements) + vacuumDefs(doc)) > 0)
 
 # output the document

tests/chained.svg

@@ -0,0 +1,8 @@
+<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
+<defs>
+  <linearGradient id="g1" />
+  <linearGradient id="g2" xlink:href="#g1" />
+  <linearGradient id="g3" xlink:href="#g2" />
+</defs>
+  <circle cx="50" cy="50" r="20" fill='blue' />
+</svg>