--- SvgParser-alpha1.1.4.lua	2012-04-17 08:27:20.000000000 +0100
+++ SvgParser.lua	2012-04-20 14:08:50.000000000 +0100
@@ -1,6 +1,37 @@
 SvgParser = Core.class()
 
+-- New declarations for SVG symbol processing
+-- Added by AWB 20/APR/2012
+local symbols={}
 
+function table.deepcopy(object)
+    local lookup_table = {}
+    local function _copy(object)
+        if type(object) ~= "table" then
+            return object
+        elseif lookup_table[object] then
+            return lookup_table[object]
+        end
+        local new_table = {}
+        lookup_table[object] = new_table
+        for index, value in pairs(object) do
+            new_table[_copy(index)] = _copy(value)
+        end
+        return setmetatable(new_table, getmetatable(object))
+    end
+    return _copy(object)
+end
+
+function Matrix:multiply(matrix)
+	local tx = self:getTx() + matrix:getTx()
+	local ty = self:getTy() + matrix:getTy()
+	local m11 = matrix:getM11() * self:getM11() + matrix:getM12() * self:getM21()
+	local m21 = matrix:getM21() * self:getM11() + matrix:getM22() * self:getM21()
+	local m12 = matrix:getM11() * self:getM12() + matrix:getM12() * self:getM22()
+	local m22 = matrix:getM21() * self:getM12() + matrix:getM22() * self:getM22()
+	return Matrix.new(m11, m12, m21, m22, tx, ty)
+end
+--- End AWB 20/APR/2012
 
 -----------------------------------------------------------------------------------------------------------
 --[[ PRIVATE ]]
@@ -224,6 +255,54 @@
 				obj:setMatrix( matrix )  -- Matrix
 			end
 			
+			--[[ <symbol /> ADDED BY AWB 20/APR/2012 ]]
+			if t.Name == "symbol" then
+				-- Register a Symbol with our symbol table.
+				-- print("symbol", t.Attributes.id, t.Attributes.viewBox, t.ChildNodes)
+				
+				for i,child in ipairs( t.ChildNodes ) do -- restart cycle
+					-- I'm not sure if symbols can contain more than one node in their definition
+					-- but here we only allow a single node
+					assert(i==1, "found more than one symbol node")
+					
+					-- print( string.format("recording symbol: %s as %s", t.Attributes.id, child.Name ))					
+					-- Record the child node in our symbol table
+					symbols["#"..t.Attributes.id]=child
+				end
+			end
+			
+			--[[ <use />  ADDED BY AWB 20/APR/2012]]
+			if t.Name == "use" then
+				-- Use a pre-registered symbol. Fetch a copy of the definition node from the symbol table. 
+				-- We have to make a deep copy because process_data() will modify it. Note, it would
+				-- be more efficient to change process_data() keep the node it is processing intact.
+				
+				local symbol=table.deepcopy(symbols[t.Attributes.href])
+				--	print( string.format("use symbol: %s(%s)", t.Attributes.href, symbolChild.Name))
+				
+				-- Process the node and retrieve the object instance that has been created
+				process_data( symbol, groups )
+				obj=groups:getChildAt(groups:getNumChildren())
+				
+				-- Symbol "use" nodes that have transforms appear to have a coordinate system based around the
+				-- centre of the symbol viewport. Here we must create a translation to account for this.
+				x=Matrix.new()				
+				if symbol.Attributes.transform then
+					local w=obj:getWidth()
+					local h=obj:getHeight()
+					local sx=matrix:getM11()
+					local sy=-matrix:getM22()
+					local tx=w/2-w*sx/2
+					local ty=-h/2-h*sy/2
+					local t=Matrix.new(1, 0, 0, 1, tx, ty)	
+					x=x:multiply(t)
+				end
+
+				-- Apply the instance transformation and our translation matrix (if any)
+				x=x:multiply(matrix):multiply(obj:getMatrix())
+				obj:setMatrix(x)
+			end
+			
 			
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