Associate structure tree elements directly to render content

* Defer the binding of PCData to struct elems using a placeholder mechanism.
* Translate text nodes to marked-content sequences in IF structure tree.
* Replace ptr with structure tree element.
* Re-order table footers so they appear at the end of the structure tree.


git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/branches/Temp_ImproveAccessibility@1236718 13f79535-47bb-0310-9956-ffa450edef68

45 files changed, 1528 insertions, 761 deletions

diff --git a/src/java/org/apache/fop/accessibility/DummyStructureTreeEventHandler.java b/src/java/org/apache/fop/accessibility/DummyStructureTreeEventHandler.java
index 80a011bab..07daf2f73 100644
--- a/src/java/org/apache/fop/accessibility/DummyStructureTreeEventHandler.java
+++ b/src/java/org/apache/fop/accessibility/DummyStructureTreeEventHandler.java
@@ -33,20 +33,31 @@ public final class DummyStructureTreeEventHandler implements StructureTreeEventH
 
     private DummyStructureTreeEventHandler() { }
 
-    /** {@inheritDoc} */
     public void startPageSequence(Locale locale) {
     }
 
-    /** {@inheritDoc} */
-    public void startNode(String name, Attributes attributes) {
+    public void endPageSequence() {
+    }
+
+    public StructureTreeElement startNode(String name, Attributes attributes) {
+        return null;
     }
 
-    /** {@inheritDoc} */
     public void endNode(String name) {
     }
 
-    /** {@inheritDoc} */
-    public void endPageSequence() {
+    public StructureTreeElement startImageNode(String name, Attributes attributes) {
+        return null;
+    }
+
+    public void endImageNode(String name) {
+    }
+
+    public StructureTreeElement startReferencedNode(String name, Attributes attributes) {
+        return null;
+    }
+
+    public void endReferencedNode(String name) {
     }
 
 }
diff --git a/src/java/org/apache/fop/accessibility/StructureTree2SAXEventAdapter.java b/src/java/org/apache/fop/accessibility/StructureTree2SAXEventAdapter.java
index 240c384d6..2cd92a5ce 100644
--- a/src/java/org/apache/fop/accessibility/StructureTree2SAXEventAdapter.java
+++ b/src/java/org/apache/fop/accessibility/StructureTree2SAXEventAdapter.java
@@ -50,7 +50,6 @@ public final class StructureTree2SAXEventAdapter implements StructureTreeEventHa
         return new StructureTree2SAXEventAdapter(contentHandler);
     }
 
-    /** {@inheritDoc} */
     public void startPageSequence(Locale locale) {
         try {
 
@@ -66,7 +65,6 @@ public final class StructureTree2SAXEventAdapter implements StructureTreeEventHa
         }
     }
 
-    /** {@inheritDoc} */
     public void endPageSequence() {
         try {
             contentHandler.endElement(IFConstants.NAMESPACE, IFConstants.EL_STRUCTURE_TREE,
@@ -81,18 +79,23 @@ public final class StructureTree2SAXEventAdapter implements StructureTreeEventHa
         }
     }
 
-    /** {@inheritDoc} */
-    public void startNode(String name, Attributes attributes) {
+    public StructureTreeElement startNode(String name, Attributes attributes) {
         try {
-            contentHandler.startElement(FOElementMapping.URI, name,
-                    FOElementMapping.STANDARD_PREFIX + ":" + name,
-                    attributes);
+            if (name.equals("#PCDATA")) {
+                name = "marked-content";
+                contentHandler.startElement(IFConstants.NAMESPACE, name,
+                        name, attributes);
+            } else {
+                contentHandler.startElement(FOElementMapping.URI, name,
+                        FOElementMapping.STANDARD_PREFIX + ":" + name,
+                        attributes);
+            }
+            return null;
         } catch (SAXException e) {
             throw new RuntimeException(e);
         }
     }
 
-    /** {@inheritDoc} */
     public void endNode(String name) {
         try {
             contentHandler.endElement(FOElementMapping.URI, name,
@@ -101,4 +104,20 @@ public final class StructureTree2SAXEventAdapter implements StructureTreeEventHa
             throw new RuntimeException(e);
         }
     }
+
+    public StructureTreeElement startImageNode(String name, Attributes attributes) {
+        return startNode(name, attributes);
+    }
+
+    public void endImageNode(String name) {
+        endNode(name);
+    }
+
+    public StructureTreeElement startReferencedNode(String name, Attributes attributes) {
+        return startNode(name, attributes);
+    }
+
+    public void endReferencedNode(String name) {
+        endNode(name);
+    }
 }
diff --git a/src/java/org/apache/fop/fo/properties/StructurePointerPropertySet.java b/src/java/org/apache/fop/accessibility/StructureTreeElement.java
index 5cce2822e..3a691c42c 100644
--- a/src/java/org/apache/fop/fo/properties/StructurePointerPropertySet.java
+++ b/src/java/org/apache/fop/accessibility/StructureTreeElement.java
@@ -17,18 +17,15 @@
 
 /* $Id$ */
 
-package org.apache.fop.fo.properties;
-
 /**
- * Defines property access methods for internal structure pointer extension properties.
+ *
  */
-public interface StructurePointerPropertySet {
-
-    /**
-     * Returns the value of the "foi:ptr" property, the internal structure pointer used
-     * for tagged PDF and other formats that support a structure tree in addition to paged content.
-     * @return the "foi:ptr" property
-     */
-    String getPtr();
+package org.apache.fop.accessibility;
 
+/**
+ * An object that represents the structure of the document in the output format.
+ * In PDF, an implementation of this interface will typically result into the
+ * creation of a structure element dictionary (a dictionary of type StructElem).
+ */
+public interface StructureTreeElement {
 }
diff --git a/src/java/org/apache/fop/accessibility/StructureTreeEventHandler.java b/src/java/org/apache/fop/accessibility/StructureTreeEventHandler.java
index d84d07870..4b94d61f1 100644
--- a/src/java/org/apache/fop/accessibility/StructureTreeEventHandler.java
+++ b/src/java/org/apache/fop/accessibility/StructureTreeEventHandler.java
@@ -32,24 +32,47 @@ public interface StructureTreeEventHandler {
 
     /**
      * Starts a page sequence structure tree node.
+     *
      * @param locale The locale of the page sequence
      */
     void startPageSequence(Locale locale);
 
     /**
      * Starts a structure tree node.
-     * @param name The name of the structure tree node
-     * @param attributes Map of node properties
+     *
+     * @param name the name of the structure tree node
+     * @param attributes the node properties
+     * @return the corresponding structure tree element
      */
-    void startNode(String name, Attributes attributes);
+    StructureTreeElement startNode(String name, Attributes attributes);
 
     /**
      * Ends a structure tree node.
-     * @param name The name of the structure tree node
+     *
+     * @param name the name of the structure tree node
      */
     void endNode(String name);
 
     /**
+     * Starts an image node.
+     *
+     * @param name the name of the structure tree node
+     * @param attributes the node properties
+     * @return the corresponding structure tree element
+     */
+    StructureTreeElement startImageNode(String name, Attributes attributes);
+
+    /**
+     * Starts a node that can be referenced by other nodes. This is usually a
+     * node that can have Marked Content References as children.
+     *
+     * @param name the name of the structure tree node
+     * @param attributes the node properties
+     * @return the corresponding structure tree element
+     */
+    StructureTreeElement startReferencedNode(String name, Attributes attributes);
+
+    /**
      * Ends a page sequence structure tree node.
      */
     void endPageSequence();
diff --git a/src/java/org/apache/fop/accessibility/FO2StructureTreeConverter.java b/src/java/org/apache/fop/accessibility/fo/FO2StructureTreeConverter.java
index e6d0193b9..47c227e9a 100644
--- a/src/java/org/apache/fop/accessibility/FO2StructureTreeConverter.java
+++ b/src/java/org/apache/fop/accessibility/fo/FO2StructureTreeConverter.java
@@ -17,21 +17,17 @@
 
 /* $Id$ */
 
-package org.apache.fop.accessibility;
+package org.apache.fop.accessibility.fo;
 
-import java.util.Locale;
+import java.util.Stack;
 
 import org.xml.sax.SAXException;
-import org.xml.sax.helpers.AttributesImpl;
 
-import org.apache.fop.apps.FOUserAgent;
+import org.apache.fop.accessibility.StructureTreeEventHandler;
 import org.apache.fop.fo.DelegatingFOEventHandler;
 import org.apache.fop.fo.FOEventHandler;
-import org.apache.fop.fo.FONode;
-import org.apache.fop.fo.extensions.ExtensionElementMapping;
+import org.apache.fop.fo.FOText;
 import org.apache.fop.fo.extensions.ExternalDocument;
-import org.apache.fop.fo.extensions.InternalElementMapping;
-import org.apache.fop.fo.flow.AbstractGraphics;
 import org.apache.fop.fo.flow.BasicLink;
 import org.apache.fop.fo.flow.Block;
 import org.apache.fop.fo.flow.BlockContainer;
@@ -61,8 +57,6 @@ import org.apache.fop.fo.pagination.Flow;
 import org.apache.fop.fo.pagination.PageSequence;
 import org.apache.fop.fo.pagination.Root;
 import org.apache.fop.fo.pagination.StaticContent;
-import org.apache.fop.fo.properties.CommonAccessibilityHolder;
-import org.apache.fop.util.XMLUtil;
 
 /**
  * Allows to create the structure tree of an FO document, by converting FO
@@ -70,354 +64,18 @@ import org.apache.fop.util.XMLUtil;
  */
 public class FO2StructureTreeConverter extends DelegatingFOEventHandler {
 
-    private int idCounter;
-
-    /** Delegates to either {@link #foToStructureTreeEventAdapter} or {@link #eventSwallower}. */
+    /** The top of the {@link converters} stack. */
     private FOEventHandler converter;
 
-    private final FOEventHandler foToStructureTreeEventAdapter;
-
-    /** The descendants of some elements like fo:leader must be ignored. */
-    private final FOEventHandler eventSwallower;
-
-    private final StructureTreeEventHandler structureTreeEventHandler;
-
-    private final class FOToStructureTreeEventAdapter extends FOEventHandler {
-
-        public FOToStructureTreeEventAdapter(FOUserAgent foUserAgent) {
-            super(foUserAgent);
-        }
-
-        @Override
-        public void startDocument() throws SAXException {
-        }
-
-        @Override
-        public void endDocument() throws SAXException {
-        }
-
-        @Override
-        public void startPageSequence(PageSequence pageSeq) {
-            Locale locale = null;
-            if (pageSeq.getLanguage() != null) {
-                if (pageSeq.getCountry() != null) {
-                    locale = new Locale(pageSeq.getLanguage(), pageSeq.getCountry());
-                } else {
-                    locale = new Locale(pageSeq.getLanguage());
-                }
-            }
-            structureTreeEventHandler.startPageSequence(locale);
-        }
-
-        @Override
-        public void endPageSequence(PageSequence pageSeq) {
-            structureTreeEventHandler.endPageSequence();
-        }
-
-        @Override
-        public void startPageNumber(PageNumber pagenum) {
-            startElementWithID(pagenum);
-        }
-
-        @Override
-        public void endPageNumber(PageNumber pagenum) {
-            endElement(pagenum);
-        }
-
-        @Override
-        public void startPageNumberCitation(PageNumberCitation pageCite) {
-            startElementWithID(pageCite);
-        }
-
-        @Override
-        public void endPageNumberCitation(PageNumberCitation pageCite) {
-            endElement(pageCite);
-        }
-
-        @Override
-        public void startPageNumberCitationLast(PageNumberCitationLast pageLast) {
-            startElementWithID(pageLast);
-        }
-
-        @Override
-        public void endPageNumberCitationLast(PageNumberCitationLast pageLast) {
-            endElement(pageLast);
-        }
-
-        @Override
-        public void startFlow(Flow fl) {
-            startElement(fl);
-        }
-
-        @Override
-        public void endFlow(Flow fl) {
-            endElement(fl);
-        }
-
-        @Override
-        public void startBlock(Block bl) {
-            startElementWithID(bl);
-        }
-
-        @Override
-        public void endBlock(Block bl) {
-            endElement(bl);
-        }
+    private final Stack<FOEventHandler> converters = new Stack<FOEventHandler>();
 
-        @Override
-        public void startBlockContainer(BlockContainer blc) {
-            startElement(blc);
-        }
+    private final Stack<FOEventRecorder> tableFooterRecorders = new Stack<FOEventRecorder>();
 
-        @Override
-        public void endBlockContainer(BlockContainer blc) {
-            endElement(blc);
-        }
+    private final FOEventHandler structureTreeEventTrigger;
 
-        @Override
-        public void startInline(Inline inl) {
-            startElementWithID(inl);
-        }
-
-        @Override
-        public void endInline(Inline inl) {
-            endElement(inl);
-        }
-
-        @Override
-        public void startTable(Table tbl) {
-            startElementWithID(tbl);
-        }
-
-        @Override
-        public void endTable(Table tbl) {
-            endElement(tbl);
-        }
-
-        @Override
-        public void startHeader(TableHeader header) {
-            startElementWithID(header);
-        }
-
-        @Override
-        public void endHeader(TableHeader header) {
-            endElement(header);
-        }
-
-        @Override
-        public void startFooter(TableFooter footer) {
-            startElementWithID(footer);
-        }
-
-        @Override
-        public void endFooter(TableFooter footer) {
-            endElement(footer);
-        }
-
-        @Override
-        public void startBody(TableBody body) {
-            startElementWithID(body);
-        }
-
-        @Override
-        public void endBody(TableBody body) {
-            endElement(body);
-        }
-
-        @Override
-        public void startRow(TableRow tr) {
-            startElementWithID(tr);
-        }
-
-        @Override
-        public void endRow(TableRow tr) {
-            endElement(tr);
-        }
-
-        @Override
-        public void startCell(TableCell tc) {
-            AttributesImpl attributes = new AttributesImpl();
-            int colSpan = tc.getNumberColumnsSpanned();
-            if (colSpan > 1) {
-                addNoNamespaceAttribute(attributes, "number-columns-spanned",
-                        Integer.toString(colSpan));
-            }
-            startElementWithID(tc, attributes);
-        }
-
-        @Override
-        public void endCell(TableCell tc) {
-            endElement(tc);
-        }
-
-        @Override
-        public void startList(ListBlock lb) {
-            startElement(lb);
-        }
-
-        @Override
-        public void endList(ListBlock lb) {
-            endElement(lb);
-        }
-
-        @Override
-        public void startListItem(ListItem li) {
-            startElement(li);
-        }
-
-        @Override
-        public void endListItem(ListItem li) {
-            endElement(li);
-        }
-
-        @Override
-        public void startListLabel(ListItemLabel listItemLabel) {
-            startElement(listItemLabel);
-        }
-
-        @Override
-        public void endListLabel(ListItemLabel listItemLabel) {
-            endElement(listItemLabel);
-        }
-
-        @Override
-        public void startListBody(ListItemBody listItemBody) {
-            startElement(listItemBody);
-        }
-
-        @Override
-        public void endListBody(ListItemBody listItemBody) {
-            endElement(listItemBody);
-        }
-
-        @Override
-        public void startStatic(StaticContent staticContent) {
-            startElement(staticContent);
-        }
-
-        @Override
-        public void endStatic(StaticContent statisContent) {
-            endElement(statisContent);
-        }
-
-        @Override
-        public void startLink(BasicLink basicLink) {
-            startElementWithID(basicLink);
-        }
-
-        @Override
-        public void endLink(BasicLink basicLink) {
-            endElement(basicLink);
-        }
-
-        @Override
-        public void image(ExternalGraphic eg) {
-            startElementWithIDAndAltText(eg);
-            endElement(eg);
-        }
-
-        @Override
-        public void startInstreamForeignObject(InstreamForeignObject ifo) {
-            startElementWithIDAndAltText(ifo);
-        }
-
-        @Override
-        public void endInstreamForeignObject(InstreamForeignObject ifo) {
-            endElement(ifo);
-        }
-
-        @Override
-        public void startFootnote(Footnote footnote) {
-            startElement(footnote);
-        }
-
-        @Override
-        public void endFootnote(Footnote footnote) {
-            endElement(footnote);
-        }
-
-        @Override
-        public void startFootnoteBody(FootnoteBody body) {
-            startElement(body);
-        }
-
-        @Override
-        public void endFootnoteBody(FootnoteBody body) {
-            endElement(body);
-        }
-
-        @Override
-        public void startWrapper(Wrapper wrapper) {
-            startElement(wrapper);
-        }
-
-        @Override
-        public void endWrapper(Wrapper wrapper) {
-            endElement(wrapper);
-        }
-
-        @Override
-        public void character(Character c) {
-            startElementWithID(c);
-            endElement(c);
-        }
-
-
-        private void startElement(FONode node) {
-            startElement(node, new AttributesImpl());
-        }
-
-        private void startElementWithID(FONode node) {
-            startElementWithID(node, new AttributesImpl());
-        }
-
-        private void startElementWithIDAndAltText(AbstractGraphics node) {
-            AttributesImpl attributes = new AttributesImpl();
-            addAttribute(attributes, ExtensionElementMapping.URI, "alt-text",
-                    ExtensionElementMapping.STANDARD_PREFIX, node.getAltText());
-            startElementWithID(node, attributes);
-        }
-
-        private void startElementWithID(FONode node, AttributesImpl attributes) {
-            String id = Integer.toHexString(idCounter++);
-            node.setPtr(id);
-            addAttribute(attributes,
-                    InternalElementMapping.URI, "ptr", InternalElementMapping.STANDARD_PREFIX, id);
-            startElement(node, attributes);
-        }
-
-        private void startElement(FONode node, AttributesImpl attributes) {
-            String localName = node.getLocalName();
-            if (node instanceof CommonAccessibilityHolder) {
-                addRole((CommonAccessibilityHolder) node, attributes);
-            }
-            structureTreeEventHandler.startNode(localName, attributes);
-        }
-
-        private void addNoNamespaceAttribute(AttributesImpl attributes, String name, String value) {
-            attributes.addAttribute("", name, name, XMLUtil.CDATA, value);
-        }
-
-        private void addAttribute(AttributesImpl attributes,
-                String namespace, String localName, String prefix, String value) {
-            assert namespace.length() > 0 && prefix.length() > 0;
-            String qualifiedName = prefix + ":" + localName;
-            attributes.addAttribute(namespace, localName, qualifiedName, XMLUtil.CDATA, value);
-        }
-
-        private void addRole(CommonAccessibilityHolder node, AttributesImpl attributes) {
-            String role = node.getCommonAccessibility().getRole();
-            if (role != null) {
-                addNoNamespaceAttribute(attributes, "role", role);
-            }
-        }
-
-        private void endElement(FONode node) {
-            String localName = node.getLocalName();
-            structureTreeEventHandler.endNode(localName);
-        }
-
-    }
+    /** The descendants of some elements like fo:leader must be ignored. */
+    private final FOEventHandler eventSwallower = new FOEventHandler() {
+    };
 
     /**
      * Creates a new instance.
@@ -428,10 +86,8 @@ public class FO2StructureTreeConverter extends DelegatingFOEventHandler {
     public FO2StructureTreeConverter(StructureTreeEventHandler structureTreeEventHandler,
             FOEventHandler delegate) {
         super(delegate);
-        this.structureTreeEventHandler = structureTreeEventHandler;
-        this.foToStructureTreeEventAdapter = new FOToStructureTreeEventAdapter(foUserAgent);
-        this.converter = foToStructureTreeEventAdapter;
-        this.eventSwallower = new FOEventHandler(foUserAgent) { };
+        this.structureTreeEventTrigger = new StructureTreeEventTrigger(structureTreeEventHandler);
+        this.converter = structureTreeEventTrigger;
     }
 
     @Override
@@ -557,11 +213,16 @@ public class FO2StructureTreeConverter extends DelegatingFOEventHandler {
     @Override
     public void startTable(Table tbl) {
         converter.startTable(tbl);
+        tableFooterRecorders.push(null);
         super.startTable(tbl);
     }
 
     @Override
     public void endTable(Table tbl) {
+        FOEventRecorder tableFooterRecorder = tableFooterRecorders.pop();
+        if (tableFooterRecorder != null) {
+            tableFooterRecorder.replay(converter);
+        }
         converter.endTable(tbl);
         super.endTable(tbl);
     }
@@ -592,6 +253,8 @@ public class FO2StructureTreeConverter extends DelegatingFOEventHandler {
 
     @Override
     public void startFooter(TableFooter footer) {
+        converters.push(converter);
+        converter = new FOEventRecorder();
         converter.startFooter(footer);
         super.startFooter(footer);
     }
@@ -599,6 +262,10 @@ public class FO2StructureTreeConverter extends DelegatingFOEventHandler {
     @Override
     public void endFooter(TableFooter footer) {
         converter.endFooter(footer);
+        /* Replace the dummy table footer with the real one. */
+        tableFooterRecorders.pop();
+        tableFooterRecorders.push((FOEventRecorder) converter);
+        converter = converters.pop();
         super.endFooter(footer);
     }
 
@@ -772,6 +439,7 @@ public class FO2StructureTreeConverter extends DelegatingFOEventHandler {
 
     @Override
     public void startLeader(Leader l) {
+        converters.push(converter);
         converter = eventSwallower;
         converter.startLeader(l);
         super.startLeader(l);
@@ -780,7 +448,7 @@ public class FO2StructureTreeConverter extends DelegatingFOEventHandler {
     @Override
     public void endLeader(Leader l) {
         converter.endLeader(l);
-        converter = foToStructureTreeEventAdapter;
+        converter = converters.pop();
         super.endLeader(l);
     }
 
@@ -803,9 +471,9 @@ public class FO2StructureTreeConverter extends DelegatingFOEventHandler {
     }
 
     @Override
-    public void characters(char[] data, int start, int length) {
-        converter.characters(data, start, length);
-        super.characters(data, start, length);
+    public void characters(FOText foText) {
+        converter.characters(foText);
+        super.characters(foText);
     }
 
     @Override
diff --git a/src/java/org/apache/fop/accessibility/fo/FOEventRecorder.java b/src/java/org/apache/fop/accessibility/fo/FOEventRecorder.java
new file mode 100644
index 000000000..b2b18046d
--- /dev/null
+++ b/src/java/org/apache/fop/accessibility/fo/FOEventRecorder.java
@@ -0,0 +1,508 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* $Id$ */
+
+package org.apache.fop.accessibility.fo;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.apache.fop.fo.FOEventHandler;
+import org.apache.fop.fo.FOText;
+import org.apache.fop.fo.flow.BasicLink;
+import org.apache.fop.fo.flow.Block;
+import org.apache.fop.fo.flow.BlockContainer;
+import org.apache.fop.fo.flow.Character;
+import org.apache.fop.fo.flow.ExternalGraphic;
+import org.apache.fop.fo.flow.Footnote;
+import org.apache.fop.fo.flow.FootnoteBody;
+import org.apache.fop.fo.flow.Inline;
+import org.apache.fop.fo.flow.InstreamForeignObject;
+import org.apache.fop.fo.flow.Leader;
+import org.apache.fop.fo.flow.ListBlock;
+import org.apache.fop.fo.flow.ListItem;
+import org.apache.fop.fo.flow.ListItemBody;
+import org.apache.fop.fo.flow.ListItemLabel;
+import org.apache.fop.fo.flow.PageNumber;
+import org.apache.fop.fo.flow.PageNumberCitation;
+import org.apache.fop.fo.flow.PageNumberCitationLast;
+import org.apache.fop.fo.flow.Wrapper;
+import org.apache.fop.fo.flow.table.Table;
+import org.apache.fop.fo.flow.table.TableBody;
+import org.apache.fop.fo.flow.table.TableCell;
+import org.apache.fop.fo.flow.table.TableColumn;
+import org.apache.fop.fo.flow.table.TableFooter;
+import org.apache.fop.fo.flow.table.TableHeader;
+import org.apache.fop.fo.flow.table.TableRow;
+
+final class FOEventRecorder extends FOEventHandler {
+
+    private interface Event {
+        void replay(FOEventHandler target);
+    }
+
+    private final List<Event> events = new ArrayList<Event>();
+
+    public void replay(FOEventHandler target) {
+        for (Event event : events) {
+            event.replay(target);
+        }
+    }
+
+    @Override
+    public void startPageNumber(final PageNumber pagenum) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.startPageNumber(pagenum);
+            }
+        });
+    }
+
+    @Override
+    public void endPageNumber(final PageNumber pagenum) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.endPageNumber(pagenum);
+            }
+        });
+    }
+
+    @Override
+    public void startPageNumberCitation(final PageNumberCitation pageCite) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.startPageNumberCitation(pageCite);
+            }
+        });
+    }
+
+    @Override
+    public void endPageNumberCitation(final PageNumberCitation pageCite) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.endPageNumberCitation(pageCite);
+            }
+        });
+    }
+
+    @Override
+    public void startPageNumberCitationLast(final PageNumberCitationLast pageLast) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.startPageNumberCitationLast(pageLast);
+            }
+        });
+    }
+
+    @Override
+    public void endPageNumberCitationLast(final PageNumberCitationLast pageLast) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.endPageNumberCitationLast(pageLast);
+            }
+        });
+    }
+
+    @Override
+    public void startBlock(final Block bl) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.startBlock(bl);
+            }
+        });
+    }
+
+    @Override
+    public void endBlock(final Block bl) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.endBlock(bl);
+            }
+        });
+    }
+
+    @Override
+    public void startBlockContainer(final BlockContainer blc) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.startBlockContainer(blc);
+            }
+        });
+    }
+
+    @Override
+    public void endBlockContainer(final BlockContainer blc) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.endBlockContainer(blc);
+            }
+        });
+    }
+
+    @Override
+    public void startInline(final Inline inl) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.startInline(inl);
+            }
+        });
+    }
+
+    @Override
+    public void endInline(final Inline inl) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.endInline(inl);
+            }
+        });
+    }
+
+    @Override
+    public void startTable(final Table tbl) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.startTable(tbl);
+            }
+        });
+    }
+
+    @Override
+    public void endTable(final Table tbl) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.endTable(tbl);
+            }
+        });
+    }
+
+    @Override
+    public void startColumn(final TableColumn tc) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.startColumn(tc);
+            }
+        });
+    }
+
+    @Override
+    public void endColumn(final TableColumn tc) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.endColumn(tc);
+            }
+        });
+    }
+
+    @Override
+    public void startHeader(final TableHeader header) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.startHeader(header);
+            }
+        });
+    }
+
+    @Override
+    public void endHeader(final TableHeader header) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.endHeader(header);
+            }
+        });
+    }
+
+    @Override
+    public void startFooter(final TableFooter footer) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.startFooter(footer);
+            }
+        });
+    }
+
+    @Override
+    public void endFooter(final TableFooter footer) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.endFooter(footer);
+            }
+        });
+    }
+
+    @Override
+    public void startBody(final TableBody body) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.startBody(body);
+            }
+        });
+    }
+
+    @Override
+    public void endBody(final TableBody body) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.endBody(body);
+            }
+        });
+    }
+
+    @Override
+    public void startRow(final TableRow tr) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.startRow(tr);
+            }
+        });
+    }
+
+    @Override
+    public void endRow(final TableRow tr) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.endRow(tr);
+            }
+        });
+    }
+
+    @Override
+    public void startCell(final TableCell tc) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.startCell(tc);
+            }
+        });
+    }
+
+    @Override
+    public void endCell(final TableCell tc) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.endCell(tc);
+            }
+        });
+    }
+
+    @Override
+    public void startList(final ListBlock lb) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.startList(lb);
+            }
+        });
+    }
+
+    @Override
+    public void endList(final ListBlock lb) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.endList(lb);
+            }
+        });
+    }
+
+    @Override
+    public void startListItem(final ListItem li) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.startListItem(li);
+            }
+        });
+    }
+
+    @Override
+    public void endListItem(final ListItem li) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.endListItem(li);
+            }
+        });
+    }
+
+    @Override
+    public void startListLabel(final ListItemLabel listItemLabel) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.startListLabel(listItemLabel);
+            }
+        });
+    }
+
+    @Override
+    public void endListLabel(final ListItemLabel listItemLabel) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.endListLabel(listItemLabel);
+            }
+        });
+    }
+
+    @Override
+    public void startListBody(final ListItemBody listItemBody) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.startListBody(listItemBody);
+            }
+        });
+    }
+
+    @Override
+    public void endListBody(final ListItemBody listItemBody) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.endListBody(listItemBody);
+            }
+        });
+    }
+
+    @Override
+    public void startLink(final BasicLink basicLink) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.startLink(basicLink);
+            }
+        });
+    }
+
+    @Override
+    public void endLink(final BasicLink basicLink) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.endLink(basicLink);
+            }
+        });
+    }
+
+    @Override
+    public void image(final ExternalGraphic eg) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.image(eg);
+            }
+        });
+    }
+
+    @Override
+    public void startInstreamForeignObject(final InstreamForeignObject ifo) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.startInstreamForeignObject(ifo);
+            }
+        });
+    }
+
+    @Override
+    public void endInstreamForeignObject(final InstreamForeignObject ifo) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.endInstreamForeignObject(ifo);
+            }
+        });
+    }
+
+    @Override
+    public void startFootnote(final Footnote footnote) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.startFootnote(footnote);
+            }
+        });
+    }
+
+    @Override
+    public void endFootnote(final Footnote footnote) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.endFootnote(footnote);
+            }
+        });
+    }
+
+    @Override
+    public void startFootnoteBody(final FootnoteBody body) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.startFootnoteBody(body);
+            }
+        });
+    }
+
+    @Override
+    public void endFootnoteBody(final FootnoteBody body) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.endFootnoteBody(body);
+            }
+        });
+    }
+
+    @Override
+    public void startLeader(final Leader l) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.startLeader(l);
+            }
+        });
+    }
+
+    @Override
+    public void endLeader(final Leader l) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.endLeader(l);
+            }
+        });
+    }
+
+    @Override
+    public void startWrapper(final Wrapper wrapper) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.startWrapper(wrapper);
+            }
+        });
+    }
+
+    @Override
+    public void endWrapper(final Wrapper wrapper) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.endWrapper(wrapper);
+            }
+        });
+    }
+
+    @Override
+    public void character(final Character c) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.character(c);
+            }
+        });
+    }
+
+    @Override
+    public void characters(final FOText foText) {
+        events.add(new Event() {
+            public void replay(FOEventHandler target) {
+                target.characters(foText);
+            }
+        });
+    }
+
+}
diff --git a/src/java/org/apache/fop/accessibility/fo/StructureTreeEventTrigger.java b/src/java/org/apache/fop/accessibility/fo/StructureTreeEventTrigger.java
new file mode 100644
index 000000000..b5cd0a5a4
--- /dev/null
+++ b/src/java/org/apache/fop/accessibility/fo/StructureTreeEventTrigger.java
@@ -0,0 +1,408 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* $Id$ */
+
+package org.apache.fop.accessibility.fo;
+
+import java.util.Locale;
+
+import org.xml.sax.SAXException;
+import org.xml.sax.helpers.AttributesImpl;
+
+import org.apache.fop.accessibility.StructureTreeElement;
+import org.apache.fop.accessibility.StructureTreeEventHandler;
+import org.apache.fop.fo.FOEventHandler;
+import org.apache.fop.fo.FONode;
+import org.apache.fop.fo.FOText;
+import org.apache.fop.fo.extensions.ExtensionElementMapping;
+import org.apache.fop.fo.flow.AbstractGraphics;
+import org.apache.fop.fo.flow.BasicLink;
+import org.apache.fop.fo.flow.Block;
+import org.apache.fop.fo.flow.BlockContainer;
+import org.apache.fop.fo.flow.Character;
+import org.apache.fop.fo.flow.ExternalGraphic;
+import org.apache.fop.fo.flow.Footnote;
+import org.apache.fop.fo.flow.FootnoteBody;
+import org.apache.fop.fo.flow.Inline;
+import org.apache.fop.fo.flow.InstreamForeignObject;
+import org.apache.fop.fo.flow.ListBlock;
+import org.apache.fop.fo.flow.ListItem;
+import org.apache.fop.fo.flow.ListItemBody;
+import org.apache.fop.fo.flow.ListItemLabel;
+import org.apache.fop.fo.flow.PageNumber;
+import org.apache.fop.fo.flow.PageNumberCitation;
+import org.apache.fop.fo.flow.PageNumberCitationLast;
+import org.apache.fop.fo.flow.Wrapper;
+import org.apache.fop.fo.flow.table.Table;
+import org.apache.fop.fo.flow.table.TableBody;
+import org.apache.fop.fo.flow.table.TableCell;
+import org.apache.fop.fo.flow.table.TableFooter;
+import org.apache.fop.fo.flow.table.TableHeader;
+import org.apache.fop.fo.flow.table.TableRow;
+import org.apache.fop.fo.pagination.Flow;
+import org.apache.fop.fo.pagination.PageSequence;
+import org.apache.fop.fo.pagination.StaticContent;
+import org.apache.fop.fo.properties.CommonAccessibilityHolder;
+import org.apache.fop.util.XMLUtil;
+
+/**
+ * A bridge between {@link FOEventHandler} and {@link StructureTreeEventHandler}.
+ */
+class StructureTreeEventTrigger extends FOEventHandler {
+
+    private StructureTreeEventHandler structureTreeEventHandler;
+
+    public StructureTreeEventTrigger(StructureTreeEventHandler structureTreeEventHandler) {
+        this.structureTreeEventHandler = structureTreeEventHandler;
+    }
+
+    @Override
+    public void startDocument() throws SAXException {
+    }
+
+    @Override
+    public void endDocument() throws SAXException {
+    }
+
+    @Override
+    public void startPageSequence(PageSequence pageSeq) {
+        Locale locale = null;
+        if (pageSeq.getLanguage() != null) {
+            if (pageSeq.getCountry() != null) {
+                locale = new Locale(pageSeq.getLanguage(), pageSeq.getCountry());
+            } else {
+                locale = new Locale(pageSeq.getLanguage());
+            }
+        }
+        structureTreeEventHandler.startPageSequence(locale);
+    }
+
+    @Override
+    public void endPageSequence(PageSequence pageSeq) {
+        structureTreeEventHandler.endPageSequence();
+    }
+
+    @Override
+    public void startPageNumber(PageNumber pagenum) {
+        startElementWithID(pagenum);
+    }
+
+    @Override
+    public void endPageNumber(PageNumber pagenum) {
+        endElement(pagenum);
+    }
+
+    @Override
+    public void startPageNumberCitation(PageNumberCitation pageCite) {
+        startElementWithID(pageCite);
+    }
+
+    @Override
+    public void endPageNumberCitation(PageNumberCitation pageCite) {
+        endElement(pageCite);
+    }
+
+    @Override
+    public void startPageNumberCitationLast(PageNumberCitationLast pageLast) {
+        startElementWithID(pageLast);
+    }
+
+    @Override
+    public void endPageNumberCitationLast(PageNumberCitationLast pageLast) {
+        endElement(pageLast);
+    }
+
+    @Override
+    public void startFlow(Flow fl) {
+        startElement(fl);
+    }
+
+    @Override
+    public void endFlow(Flow fl) {
+        endElement(fl);
+    }
+
+    @Override
+    public void startBlock(Block bl) {
+        startElement(bl);
+    }
+
+    @Override
+    public void endBlock(Block bl) {
+        endElement(bl);
+    }
+
+    @Override
+    public void startBlockContainer(BlockContainer blc) {
+        startElement(blc);
+    }
+
+    @Override
+    public void endBlockContainer(BlockContainer blc) {
+        endElement(blc);
+    }
+
+    @Override
+    public void startInline(Inline inl) {
+        startElement(inl);
+    }
+
+    @Override
+    public void endInline(Inline inl) {
+        endElement(inl);
+    }
+
+    @Override
+    public void startTable(Table tbl) {
+        startElement(tbl);
+    }
+
+    @Override
+    public void endTable(Table tbl) {
+        endElement(tbl);
+    }
+
+    @Override
+    public void startHeader(TableHeader header) {
+        startElement(header);
+    }
+
+    @Override
+    public void endHeader(TableHeader header) {
+        endElement(header);
+    }
+
+    @Override
+    public void startFooter(TableFooter footer) {
+        startElement(footer);
+    }
+
+    @Override
+    public void endFooter(TableFooter footer) {
+        endElement(footer);
+    }
+
+    @Override
+    public void startBody(TableBody body) {
+        startElement(body);
+    }
+
+    @Override
+    public void endBody(TableBody body) {
+        endElement(body);
+    }
+
+    @Override
+    public void startRow(TableRow tr) {
+        startElement(tr);
+    }
+
+    @Override
+    public void endRow(TableRow tr) {
+        endElement(tr);
+    }
+
+    @Override
+    public void startCell(TableCell tc) {
+        AttributesImpl attributes = new AttributesImpl();
+        int colSpan = tc.getNumberColumnsSpanned();
+        if (colSpan > 1) {
+            addNoNamespaceAttribute(attributes, "number-columns-spanned",
+                    Integer.toString(colSpan));
+        }
+        startElement(tc, attributes);
+    }
+
+    @Override
+    public void endCell(TableCell tc) {
+        endElement(tc);
+    }
+
+    @Override
+    public void startList(ListBlock lb) {
+        startElement(lb);
+    }
+
+    @Override
+    public void endList(ListBlock lb) {
+        endElement(lb);
+    }
+
+    @Override
+    public void startListItem(ListItem li) {
+        startElement(li);
+    }
+
+    @Override
+    public void endListItem(ListItem li) {
+        endElement(li);
+    }
+
+    @Override
+    public void startListLabel(ListItemLabel listItemLabel) {
+        startElement(listItemLabel);
+    }
+
+    @Override
+    public void endListLabel(ListItemLabel listItemLabel) {
+        endElement(listItemLabel);
+    }
+
+    @Override
+    public void startListBody(ListItemBody listItemBody) {
+        startElement(listItemBody);
+    }
+
+    @Override
+    public void endListBody(ListItemBody listItemBody) {
+        endElement(listItemBody);
+    }
+
+    @Override
+    public void startStatic(StaticContent staticContent) {
+        startElement(staticContent);
+    }
+
+    @Override
+    public void endStatic(StaticContent statisContent) {
+        endElement(statisContent);
+    }
+
+    @Override
+    public void startLink(BasicLink basicLink) {
+        startElementWithID(basicLink);
+    }
+
+    @Override
+    public void endLink(BasicLink basicLink) {
+        endElement(basicLink);
+    }
+
+    @Override
+    public void image(ExternalGraphic eg) {
+        startElementWithIDAndAltText(eg);
+        endElement(eg);
+    }
+
+    @Override
+    public void startInstreamForeignObject(InstreamForeignObject ifo) {
+        startElementWithIDAndAltText(ifo);
+    }
+
+    @Override
+    public void endInstreamForeignObject(InstreamForeignObject ifo) {
+        endElement(ifo);
+    }
+
+    @Override
+    public void startFootnote(Footnote footnote) {
+        startElement(footnote);
+    }
+
+    @Override
+    public void endFootnote(Footnote footnote) {
+        endElement(footnote);
+    }
+
+    @Override
+    public void startFootnoteBody(FootnoteBody body) {
+        startElement(body);
+    }
+
+    @Override
+    public void endFootnoteBody(FootnoteBody body) {
+        endElement(body);
+    }
+
+    @Override
+    public void startWrapper(Wrapper wrapper) {
+        startElement(wrapper);
+    }
+
+    @Override
+    public void endWrapper(Wrapper wrapper) {
+        endElement(wrapper);
+    }
+
+    @Override
+    public void character(Character c) {
+        startElementWithID(c);
+        endElement(c);
+    }
+
+    @Override
+    public void characters(FOText foText) {
+        startElementWithID(foText);
+        endElement(foText);
+    }
+
+
+    private void startElement(FONode node) {
+        startElement(node, new AttributesImpl());
+    }
+
+    private void startElementWithID(FONode node) {
+        AttributesImpl attributes = new AttributesImpl();
+        String localName = node.getLocalName();
+        if (node instanceof CommonAccessibilityHolder) {
+            addRole((CommonAccessibilityHolder) node, attributes);
+        }
+        node.setStructureTreeElement(structureTreeEventHandler.startReferencedNode(localName, attributes));
+    }
+
+    private void startElementWithIDAndAltText(AbstractGraphics node) {
+        AttributesImpl attributes = new AttributesImpl();
+        String localName = node.getLocalName();
+        addRole(node, attributes);
+        addAttribute(attributes, ExtensionElementMapping.URI, "alt-text",
+                ExtensionElementMapping.STANDARD_PREFIX, node.getAltText());
+        node.setStructureTreeElement(structureTreeEventHandler.startImageNode(localName, attributes));
+    }
+
+    private StructureTreeElement startElement(FONode node, AttributesImpl attributes) {
+        String localName = node.getLocalName();
+        if (node instanceof CommonAccessibilityHolder) {
+            addRole((CommonAccessibilityHolder) node, attributes);
+        }
+        return structureTreeEventHandler.startNode(localName, attributes);
+    }
+
+    private void addNoNamespaceAttribute(AttributesImpl attributes, String name, String value) {
+        attributes.addAttribute("", name, name, XMLUtil.CDATA, value);
+    }
+
+    private void addAttribute(AttributesImpl attributes,
+            String namespace, String localName, String prefix, String value) {
+        assert namespace.length() > 0 && prefix.length() > 0;
+        String qualifiedName = prefix + ":" + localName;
+        attributes.addAttribute(namespace, localName, qualifiedName, XMLUtil.CDATA, value);
+    }
+
+    private void addRole(CommonAccessibilityHolder node, AttributesImpl attributes) {
+        String role = node.getCommonAccessibility().getRole();
+        if (role != null) {
+            addNoNamespaceAttribute(attributes, "role", role);
+        }
+    }
+
+    private void endElement(FONode node) {
+        String localName = node.getLocalName();
+        structureTreeEventHandler.endNode(localName);
+    }
+
+}
diff --git a/src/java/org/apache/fop/area/AreaTreeParser.java b/src/java/org/apache/fop/area/AreaTreeParser.java
index 545c9015d..29a363495 100644
--- a/src/java/org/apache/fop/area/AreaTreeParser.java
+++ b/src/java/org/apache/fop/area/AreaTreeParser.java
@@ -728,7 +728,6 @@ public class AreaTreeParser {
                 setTraits(attributes, ip, SUBSET_BOX);
                 setTraits(attributes, ip, SUBSET_COLOR);
                 setTraits(attributes, ip, SUBSET_LINK);
-                setPtr(ip, attributes);
                 Area parent = (Area)areaStack.peek();
                 parent.addChildArea(ip);
                 areaStack.push(ip);
@@ -777,7 +776,6 @@ public class AreaTreeParser {
                         "tlsadjust", 0));
                 text.setTextWordSpaceAdjust(XMLUtil.getAttributeAsInt(attributes,
                         "twsadjust", 0));
-                setPtr(text, attributes);
                 Area parent = (Area)areaStack.peek();
                 parent.addChildArea(text);
                 areaStack.push(text);
@@ -870,7 +868,6 @@ public class AreaTreeParser {
                 viewport.setContentPosition(XMLUtil.getAttributeAsRectangle2D(attributes, "pos"));
                 viewport.setClip(XMLUtil.getAttributeAsBoolean(attributes, "clip", false));
                 viewport.setOffset(XMLUtil.getAttributeAsInt(attributes, "offset", 0));
-                setPtr(viewport, attributes);
                 Area parent = (Area)areaStack.peek();
                 parent.addChildArea(viewport);
                 areaStack.push(viewport);
@@ -889,7 +886,6 @@ public class AreaTreeParser {
                 transferForeignObjects(attributes, image);
                 setAreaAttributes(attributes, image);
                 setTraits(attributes, image, SUBSET_COMMON);
-                setPtr(image, attributes);
                 getCurrentViewport().setContent(image);
             }
         }
@@ -1174,13 +1170,6 @@ public class AreaTreeParser {
             }
         }
 
-        private void setPtr(Area area, Attributes attributes) {
-            String ptr = attributes.getValue("ptr");
-            if (ptr != null) {
-                area.addTrait(Trait.PTR, ptr);
-            }
-        }
-
         /** {@inheritDoc} */
         public void characters(char[] ch, int start, int length) throws SAXException {
             if (delegate != null) {
diff --git a/src/java/org/apache/fop/area/Trait.java b/src/java/org/apache/fop/area/Trait.java
index 042b65337..d9194559d 100644
--- a/src/java/org/apache/fop/area/Trait.java
+++ b/src/java/org/apache/fop/area/Trait.java
@@ -153,8 +153,8 @@ public final class Trait implements Serializable {
     /** Trait for color of linethrough decorations when rendering inline parent. */
     public static final Integer LINETHROUGH_COLOR = 36;
 
-    /** The ptr trait. Used for accessibility   */
-    public static final Integer PTR = 37;
+    /** For navigation in the document structure. */
+    public static final Integer STRUCTURE_TREE_ELEMENT = 37;
 
     /** Maximum value used by trait keys */
     public static final int MAX_TRAIT_KEY = 37;
@@ -186,7 +186,7 @@ public final class Trait implements Serializable {
     static {
         // Create a hashmap mapping trait code to name for external representation
         //put(ID_LINK, new TraitInfo("id-link", String.class));
-        put(PTR,            new TraitInfo("ptr", String.class));
+        put(STRUCTURE_TREE_ELEMENT, new TraitInfo("structure-tree-element", String.class));
         put(INTERNAL_LINK,  new TraitInfo("internal-link", InternalLink.class));
         put(EXTERNAL_LINK,  new TraitInfo("external-link", ExternalLink.class));
         put(FONT,           new TraitInfo("font", FontTriplet.class));
diff --git a/src/java/org/apache/fop/fo/DelegatingFOEventHandler.java b/src/java/org/apache/fop/fo/DelegatingFOEventHandler.java
index ed85bd1c9..e64106a80 100644
--- a/src/java/org/apache/fop/fo/DelegatingFOEventHandler.java
+++ b/src/java/org/apache/fop/fo/DelegatingFOEventHandler.java
@@ -387,8 +387,8 @@ public abstract class DelegatingFOEventHandler extends FOEventHandler {
     }
 
     @Override
-    public void characters(char[] data, int start, int length) {
-        delegate.characters(data, start, length);
+    public void characters(FOText foText) {
+        delegate.characters(foText);
     }
 
     @Override
diff --git a/src/java/org/apache/fop/fo/FOEventHandler.java b/src/java/org/apache/fop/fo/FOEventHandler.java
index 1f3514dea..bed1f3677 100644
--- a/src/java/org/apache/fop/fo/FOEventHandler.java
+++ b/src/java/org/apache/fop/fo/FOEventHandler.java
@@ -88,6 +88,10 @@ public abstract class FOEventHandler {
         this.fontInfo.setEventListener(new FontEventAdapter(foUserAgent.getEventBroadcaster()));
     }
 
+    /** Constructor for sub-classes that do not need an {@link FOUserAgent} instance. */
+    protected FOEventHandler() {
+    }
+
     /**
      * Returns the User Agent object associated with this FOEventHandler.
      * @return the User Agent object
@@ -532,11 +536,9 @@ public abstract class FOEventHandler {
 
     /**
      * Process character data.
-     * @param data Array of characters to process.
-     * @param start Offset for characters to process.
-     * @param length Portion of array to process.
+     * @param foText text to process
      */
-    public void characters(char[] data, int start, int length) {
+    public void characters(FOText foText) {
     }
 
     /**
diff --git a/src/java/org/apache/fop/fo/FONode.java b/src/java/org/apache/fop/fo/FONode.java
index 4946f6d5c..622ff86d4 100644
--- a/src/java/org/apache/fop/fo/FONode.java
+++ b/src/java/org/apache/fop/fo/FONode.java
@@ -32,6 +32,7 @@ import org.apache.commons.logging.LogFactory;
 
 import org.apache.xmlgraphics.util.QName;
 
+import org.apache.fop.accessibility.StructureTreeElement;
 import org.apache.fop.apps.FOPException;
 import org.apache.fop.apps.FOUserAgent;
 import org.apache.fop.fo.extensions.ExtensionAttachment;
@@ -912,7 +913,7 @@ public abstract class FONode implements Cloneable {
 
     }
 
-    public void setPtr(String ptr) {
+    public void setStructureTreeElement(StructureTreeElement structureTreeElement) {
         throw new UnsupportedOperationException();
     }
 
diff --git a/src/java/org/apache/fop/fo/FOText.java b/src/java/org/apache/fop/fo/FOText.java
index 5db11f731..3858cdea9 100644
--- a/src/java/org/apache/fop/fo/FOText.java
+++ b/src/java/org/apache/fop/fo/FOText.java
@@ -25,6 +25,7 @@ import java.util.NoSuchElementException;
 
 import org.xml.sax.Locator;
 
+import org.apache.fop.accessibility.StructureTreeElement;
 import org.apache.fop.apps.FOPException;
 import org.apache.fop.datatypes.Length;
 import org.apache.fop.fo.flow.Block;
@@ -79,6 +80,8 @@ public class FOText extends FONode implements CharSequence {
     /** Holds the text decoration values. May be null */
     private CommonTextDecoration textDecoration;
 
+    private StructureTreeElement structureTreeElement;
+
     private static final int IS_WORD_CHAR_FALSE = 0;
     private static final int IS_WORD_CHAR_TRUE = 1;
     private static final int IS_WORD_CHAR_MAYBE = 2;
@@ -115,25 +118,14 @@ public class FOText extends FONode implements CharSequence {
     /**
      * Return the array of characters for this instance.
      *
-     * @return  a char array containing the text
+     * @return  a char sequence containing the text
      */
-    public char[] getCharArray() {
-
+    public CharSequence getCharSequence() {
         if (this.charBuffer == null) {
             return null;
         }
-
-        if (this.charBuffer.hasArray()) {
-            return this.charBuffer.array();
-        }
-
-        // only if the buffer implementation has
-        // no accessible backing array, return a new one
-        char[] ca = new char[this.charBuffer.limit()];
         this.charBuffer.rewind();
-        this.charBuffer.get(ca);
-        return ca;
-
+        return this.charBuffer.asReadOnlyBuffer().subSequence(0, this.charBuffer.limit());
     }
 
     /** {@inheritDoc} */
@@ -176,8 +168,7 @@ public class FOText extends FONode implements CharSequence {
     /** {@inheritDoc} */
     protected void endOfNode() throws FOPException {
         super.endOfNode();
-        getFOEventHandler().characters(
-                this.getCharArray(), 0, this.charBuffer.limit());
+        getFOEventHandler().characters(this);
     }
 
     /** {@inheritDoc} */
@@ -670,4 +661,14 @@ public class FOText extends FONode implements CharSequence {
             this.charBuffer.rewind();
         }
     }
+
+    @Override
+    public void setStructureTreeElement(StructureTreeElement structureTreeElement) {
+        this.structureTreeElement = structureTreeElement;
+    }
+
+    public StructureTreeElement getStructureTreeElement() {
+        return structureTreeElement;
+    }
+
 }
diff --git a/src/java/org/apache/fop/fo/FOTreeBuilder.java b/src/java/org/apache/fop/fo/FOTreeBuilder.java
index b053692d6..ece4e5448 100644
--- a/src/java/org/apache/fop/fo/FOTreeBuilder.java
+++ b/src/java/org/apache/fop/fo/FOTreeBuilder.java
@@ -33,7 +33,7 @@ import org.apache.commons.logging.LogFactory;
 
 import org.apache.xmlgraphics.util.QName;
 
-import org.apache.fop.accessibility.FO2StructureTreeConverter;
+import org.apache.fop.accessibility.fo.FO2StructureTreeConverter;
 import org.apache.fop.apps.FOPException;
 import org.apache.fop.apps.FOUserAgent;
 import org.apache.fop.apps.FormattingResults;
diff --git a/src/java/org/apache/fop/fo/extensions/InternalElementMapping.java b/src/java/org/apache/fop/fo/extensions/InternalElementMapping.java
index e939841e1..687952d25 100644
--- a/src/java/org/apache/fop/fo/extensions/InternalElementMapping.java
+++ b/src/java/org/apache/fop/fo/extensions/InternalElementMapping.java
@@ -37,11 +37,18 @@ public class InternalElementMapping extends ElementMapping {
     /** The standard XML prefix for elements and attributes in this namespace. */
     public static final String STANDARD_PREFIX = "foi";
 
+    /** The "struct-id" attribute, to identify a structure tree element. */
+    public static final String STRUCT_ID = "struct-id";
+
+    /** The "struct-ref" attribute, to refer to a structure tree element. */
+    public static final String STRUCT_REF = "struct-ref";
+
     private static final Set<String> PROPERTY_ATTRIBUTES = new java.util.HashSet<String>();
 
     static {
         //These are FOP's extension properties for accessibility
-        PROPERTY_ATTRIBUTES.add("ptr");
+        PROPERTY_ATTRIBUTES.add(STRUCT_ID);
+        PROPERTY_ATTRIBUTES.add(STRUCT_REF);
     }
 
     /**
diff --git a/src/java/org/apache/fop/fo/flow/AbstractGraphics.java b/src/java/org/apache/fop/fo/flow/AbstractGraphics.java
index 67a33d088..2b8fa8a0b 100644
--- a/src/java/org/apache/fop/fo/flow/AbstractGraphics.java
+++ b/src/java/org/apache/fop/fo/flow/AbstractGraphics.java
@@ -19,6 +19,7 @@
 
 package org.apache.fop.fo.flow;
 
+import org.apache.fop.accessibility.StructureTreeElement;
 import org.apache.fop.apps.FOPException;
 import org.apache.fop.datatypes.Length;
 import org.apache.fop.fo.FONode;
@@ -31,7 +32,7 @@ import org.apache.fop.fo.properties.CommonBorderPaddingBackground;
 import org.apache.fop.fo.properties.KeepProperty;
 import org.apache.fop.fo.properties.LengthRangeProperty;
 import org.apache.fop.fo.properties.SpaceProperty;
-import org.apache.fop.fo.properties.StructurePointerPropertySet;
+import org.apache.fop.fo.properties.StructureTreeElementHolder;
 
 /**
  * Common base class for the <a href="http://www.w3.org/TR/xsl/#fo_instream-foreign-object">
@@ -40,7 +41,7 @@ import org.apache.fop.fo.properties.StructurePointerPropertySet;
  * <code>fo:external-graphic</code></a> flow formatting objects.
  */
 public abstract class AbstractGraphics extends FObj
-        implements GraphicsProperties, StructurePointerPropertySet, CommonAccessibilityHolder {
+        implements GraphicsProperties, StructureTreeElementHolder, CommonAccessibilityHolder {
 
     // The value of properties relevant for fo:instream-foreign-object
     // and external-graphics.
@@ -66,7 +67,7 @@ public abstract class AbstractGraphics extends FObj
     private int textAlign;
     private Length width;
     private String altText;
-    private String ptr;   // used for accessibility
+    private StructureTreeElement structureTreeElement;
     // Unused but valid items, commented out for performance:
     //     private CommonAccessibility commonAccessibility;
     //     private CommonAural commonAural;
@@ -226,13 +227,13 @@ public abstract class AbstractGraphics extends FObj
     }
 
     @Override
-    public void setPtr(String ptr) {
-        this.ptr = ptr;
+    public void setStructureTreeElement(StructureTreeElement structureTreeElement) {
+        this.structureTreeElement = structureTreeElement;
     }
 
     /** {@inheritDoc} */
-    public String getPtr() {
-        return ptr;
+    public StructureTreeElement getStructureTreeElement() {
+        return structureTreeElement;
     }
 
     public String getAltText() {
diff --git a/src/java/org/apache/fop/fo/flow/AbstractPageNumberCitation.java b/src/java/org/apache/fop/fo/flow/AbstractPageNumberCitation.java
index bbb632b29..108896d91 100644
--- a/src/java/org/apache/fop/fo/flow/AbstractPageNumberCitation.java
+++ b/src/java/org/apache/fop/fo/flow/AbstractPageNumberCitation.java
@@ -24,6 +24,7 @@ import java.awt.Color;
 import org.xml.sax.Attributes;
 import org.xml.sax.Locator;
 
+import org.apache.fop.accessibility.StructureTreeElement;
 import org.apache.fop.apps.FOPException;
 import org.apache.fop.datatypes.Length;
 import org.apache.fop.fo.Constants;
@@ -37,7 +38,7 @@ import org.apache.fop.fo.properties.CommonBorderPaddingBackground;
 import org.apache.fop.fo.properties.CommonFont;
 import org.apache.fop.fo.properties.CommonTextDecoration;
 import org.apache.fop.fo.properties.SpaceProperty;
-import org.apache.fop.fo.properties.StructurePointerPropertySet;
+import org.apache.fop.fo.properties.StructureTreeElementHolder;
 
 /**
  * Common base class for the <a href="http://www.w3.org/TR/xsl/#fo_page-number-citation">
@@ -46,7 +47,7 @@ import org.apache.fop.fo.properties.StructurePointerPropertySet;
  * <code>fo:page-number-citation-last</code></a> objects.
  */
 public abstract class AbstractPageNumberCitation extends FObj
-        implements StructurePointerPropertySet, CommonAccessibilityHolder {
+        implements StructureTreeElementHolder, CommonAccessibilityHolder {
 
     // The value of properties relevant for fo:page-number-citation(-last).
     private CommonAccessibility commonAccessibility;
@@ -56,7 +57,7 @@ public abstract class AbstractPageNumberCitation extends FObj
     private int alignmentBaseline;
     private Length baselineShift;
     private int dominantBaseline;
-    private String ptr;  // used for accessibility
+    private StructureTreeElement structureTreeElement;
     // private ToBeImplementedProperty letterSpacing;
     private SpaceProperty lineHeight;
     private String refId;
@@ -151,13 +152,13 @@ public abstract class AbstractPageNumberCitation extends FObj
     }
 
     @Override
-    public void setPtr(String ptr) {
-        this.ptr = ptr;
+    public void setStructureTreeElement(StructureTreeElement structureTreeElement) {
+        this.structureTreeElement = structureTreeElement;
     }
 
     /** {@inheritDoc} */
-    public String getPtr() {
-        return ptr;
+    public StructureTreeElement getStructureTreeElement() {
+        return structureTreeElement;
     }
 
     /** @return the "alignment-adjust" property */
diff --git a/src/java/org/apache/fop/fo/flow/BasicLink.java b/src/java/org/apache/fop/fo/flow/BasicLink.java
index 7bff2d521..0d6d5d9b4 100644
--- a/src/java/org/apache/fop/fo/flow/BasicLink.java
+++ b/src/java/org/apache/fop/fo/flow/BasicLink.java
@@ -21,12 +21,13 @@ package org.apache.fop.fo.flow;
 
 import org.xml.sax.Locator;
 
+import org.apache.fop.accessibility.StructureTreeElement;
 import org.apache.fop.apps.FOPException;
 import org.apache.fop.datatypes.Length;
 import org.apache.fop.fo.FONode;
 import org.apache.fop.fo.PropertyList;
 import org.apache.fop.fo.ValidationException;
-import org.apache.fop.fo.properties.StructurePointerPropertySet;
+import org.apache.fop.fo.properties.StructureTreeElementHolder;
 
 /**
  * Class modelling the <a href="http://www.w3.org/TR/xsl/#fo_basic-link">
@@ -36,14 +37,14 @@ import org.apache.fop.fo.properties.StructurePointerPropertySet;
  * and whether that link is external (uses a URI) or internal (an id
  * reference).
  */
-public class BasicLink extends InlineLevel implements StructurePointerPropertySet {
+public class BasicLink extends InlineLevel implements StructureTreeElementHolder {
 
     // The value of properties relevant for fo:basic-link.
     private Length alignmentAdjust;
     private int alignmentBaseline;
     private Length baselineShift;
     private int dominantBaseline;
-    private String ptr;
+    private StructureTreeElement structureTreeElement;
     // private ToBeImplementedProperty destinationPlacementOffset;
     private String externalDestination;
     // private ToBeImplementedProperty indicateDestination;
@@ -143,13 +144,13 @@ public class BasicLink extends InlineLevel implements StructurePointerPropertySe
     }
 
     @Override
-    public void setPtr(String ptr) {
-        this.ptr = ptr;
+    public void setStructureTreeElement(StructureTreeElement structureTreeElement) {
+        this.structureTreeElement = structureTreeElement;
     }
 
     /** {@inheritDoc} */
-    public String getPtr() {
-        return ptr;
+    public StructureTreeElement getStructureTreeElement() {
+        return structureTreeElement;
     }
 
     /**
diff --git a/src/java/org/apache/fop/fo/flow/Block.java b/src/java/org/apache/fop/fo/flow/Block.java
index b1705288a..4e5b6f15f 100644
--- a/src/java/org/apache/fop/fo/flow/Block.java
+++ b/src/java/org/apache/fop/fo/flow/Block.java
@@ -42,13 +42,12 @@ import org.apache.fop.fo.properties.CommonMarginBlock;
 import org.apache.fop.fo.properties.CommonRelativePosition;
 import org.apache.fop.fo.properties.KeepProperty;
 import org.apache.fop.fo.properties.SpaceProperty;
-import org.apache.fop.fo.properties.StructurePointerPropertySet;
 
  /**
   * Class modelling the <a href="http://www.w3.org/TR/xsl/#fo_block">
   * <code>fo:block object</code></a>.
   */
-public class Block extends FObjMixed implements BreakPropertySet, StructurePointerPropertySet,
+public class Block extends FObjMixed implements BreakPropertySet,
         CommonAccessibilityHolder {
 
     // used for FO validation
@@ -77,7 +76,6 @@ public class Block extends FObjMixed implements BreakPropertySet, StructurePoint
     private int lineHeightShiftAdjustment;
     private int lineStackingStrategy;
     private Numeric orphans;
-    private String ptr;  //used for accessibility
     private int whiteSpaceTreatment;
     private int span;
     private int textAlign;
@@ -183,16 +181,6 @@ public class Block extends FObjMixed implements BreakPropertySet, StructurePoint
         return breakAfter;
     }
 
-    @Override
-    public void setPtr(String ptr) {
-        this.ptr = ptr;
-    }
-
-    /** {@inheritDoc} */
-    public String getPtr() {
-        return ptr;
-    }
-
     /** @return the "break-before" property. */
     public int getBreakBefore() {
         return breakBefore;
diff --git a/src/java/org/apache/fop/fo/flow/Character.java b/src/java/org/apache/fop/fo/flow/Character.java
index a33bea53d..c4de9fb72 100644
--- a/src/java/org/apache/fop/fo/flow/Character.java
+++ b/src/java/org/apache/fop/fo/flow/Character.java
@@ -24,6 +24,7 @@ import java.util.NoSuchElementException;
 
 import org.xml.sax.Locator;
 
+import org.apache.fop.accessibility.StructureTreeElement;
 import org.apache.fop.apps.FOPException;
 import org.apache.fop.datatypes.Length;
 import org.apache.fop.fo.CharIterator;
@@ -38,13 +39,13 @@ import org.apache.fop.fo.properties.CommonTextDecoration;
 import org.apache.fop.fo.properties.KeepProperty;
 import org.apache.fop.fo.properties.Property;
 import org.apache.fop.fo.properties.SpaceProperty;
-import org.apache.fop.fo.properties.StructurePointerPropertySet;
+import org.apache.fop.fo.properties.StructureTreeElementHolder;
 
 /**
  * Class modelling the <a href="http://www.w3.org/TR/xsl/#fo_character">
  * <code>fo:character</code></a> object.
  */
-public class Character extends FObj implements StructurePointerPropertySet {
+public class Character extends FObj implements StructureTreeElementHolder {
     // The value of properties relevant for fo:character.
     private CommonBorderPaddingBackground commonBorderPaddingBackground;
     private CommonFont commonFont;
@@ -63,7 +64,7 @@ public class Character extends FObj implements StructurePointerPropertySet {
     private CommonTextDecoration textDecoration;
     // private ToBeImplementedProperty textShadow;
     private Property wordSpacing;
-    private String ptr;  // used for accessibility
+    private StructureTreeElement structureTreeElement;
     // Unused but valid items, commented out for performance:
     //     private CommonAural commonAural;
     //     private CommonMarginInline commonMarginInline;
@@ -210,13 +211,13 @@ public class Character extends FObj implements StructurePointerPropertySet {
     }
 
     @Override
-    public void setPtr(String ptr) {
-        this.ptr = ptr;
+    public void setStructureTreeElement(StructureTreeElement structureTreeElement) {
+        this.structureTreeElement = structureTreeElement;
     }
 
     /** {@inheritDoc} */
-    public String getPtr() {
-        return ptr;
+    public StructureTreeElement getStructureTreeElement() {
+        return structureTreeElement;
     }
 
     /** {@inheritDoc} */
diff --git a/src/java/org/apache/fop/fo/flow/Inline.java b/src/java/org/apache/fop/fo/flow/Inline.java
index e458184f4..debf6bbf6 100644
--- a/src/java/org/apache/fop/fo/flow/Inline.java
+++ b/src/java/org/apache/fop/fo/flow/Inline.java
@@ -26,19 +26,17 @@ import org.apache.fop.datatypes.Length;
 import org.apache.fop.fo.FONode;
 import org.apache.fop.fo.PropertyList;
 import org.apache.fop.fo.ValidationException;
-import org.apache.fop.fo.properties.StructurePointerPropertySet;
 
 /**
  * Class modelling the <a href="http://www.w3.org/TR/xsl/#fo_inline">
  * <code>fo:inline</code></a> formatting object.
  */
-public class Inline extends InlineLevel implements StructurePointerPropertySet {
+public class Inline extends InlineLevel {
     // The value of properties relevant for fo:inline.
     // See also superclass InlineLevel
     private Length alignmentAdjust;
     private int alignmentBaseline;
     private Length baselineShift;
-    private String ptr;  // used for accessibility
     private int dominantBaseline;
     // Unused but valid items, commented out for performance:
     //     private CommonRelativePosition commonRelativePosition;
@@ -147,16 +145,6 @@ public class Inline extends InlineLevel implements StructurePointerPropertySet {
         return dominantBaseline;
     }
 
-    @Override
-    public void setPtr(String ptr) {
-        this.ptr = ptr;
-    }
-
-    /** {@inheritDoc} */
-    public String getPtr() {
-        return ptr;
-    }
-
     /** {@inheritDoc} */
     public String getLocalName() {
         return "inline";
diff --git a/src/java/org/apache/fop/fo/flow/PageNumber.java b/src/java/org/apache/fop/fo/flow/PageNumber.java
index c0373aa7f..0e5ce5071 100644
--- a/src/java/org/apache/fop/fo/flow/PageNumber.java
+++ b/src/java/org/apache/fop/fo/flow/PageNumber.java
@@ -23,6 +23,7 @@ import java.awt.Color;
 
 import org.xml.sax.Locator;
 
+import org.apache.fop.accessibility.StructureTreeElement;
 import org.apache.fop.apps.FOPException;
 import org.apache.fop.datatypes.Length;
 import org.apache.fop.fo.Constants;
@@ -36,14 +37,14 @@ import org.apache.fop.fo.properties.CommonBorderPaddingBackground;
 import org.apache.fop.fo.properties.CommonFont;
 import org.apache.fop.fo.properties.CommonTextDecoration;
 import org.apache.fop.fo.properties.SpaceProperty;
-import org.apache.fop.fo.properties.StructurePointerPropertySet;
+import org.apache.fop.fo.properties.StructureTreeElementHolder;
 
 /**
  * Class modelling the <a href="http://www.w3.org/TR/xsl/#fo_page-number">
  * <code>fo:page-number</code></a> object.
  */
 public class PageNumber extends FObj
-        implements StructurePointerPropertySet, CommonAccessibilityHolder {
+        implements StructureTreeElementHolder, CommonAccessibilityHolder {
     // The value of properties relevant for fo:page-number.
     private CommonAccessibility commonAccessibility;
     private CommonBorderPaddingBackground commonBorderPaddingBackground;
@@ -52,7 +53,7 @@ public class PageNumber extends FObj
     private int alignmentBaseline;
     private Length baselineShift;
     private int dominantBaseline;
-    private String ptr; // used for accessibility
+    private StructureTreeElement structureTreeElement;
     // private ToBeImplementedProperty letterSpacing;
     private SpaceProperty lineHeight;
     /** Holds the text decoration values. May be null */
@@ -176,13 +177,13 @@ public class PageNumber extends FObj
     }
 
     @Override
-    public void setPtr(String ptr) {
-        this.ptr = ptr;
+    public void setStructureTreeElement(StructureTreeElement structureTreeElement) {
+        this.structureTreeElement = structureTreeElement;
     }
 
     /** {@inheritDoc} */
-    public String getPtr() {
-        return ptr;
+    public StructureTreeElement getStructureTreeElement() {
+        return structureTreeElement;
     }
 
     /** {@inheritDoc} */
diff --git a/src/java/org/apache/fop/fo/flow/table/TableFObj.java b/src/java/org/apache/fop/fo/flow/table/TableFObj.java
index 0da7b9458..2506c26b4 100644
--- a/src/java/org/apache/fop/fo/flow/table/TableFObj.java
+++ b/src/java/org/apache/fop/fo/flow/table/TableFObj.java
@@ -36,19 +36,17 @@ import org.apache.fop.fo.properties.EnumProperty;
 import org.apache.fop.fo.properties.NumberProperty;
 import org.apache.fop.fo.properties.Property;
 import org.apache.fop.fo.properties.PropertyMaker;
-import org.apache.fop.fo.properties.StructurePointerPropertySet;
 import org.apache.fop.layoutmgr.table.CollapsingBorderModel;
 
 /**
  * Common base class for table-related FOs
  */
-public abstract class TableFObj extends FObj implements StructurePointerPropertySet {
+public abstract class TableFObj extends FObj {
 
     private Numeric borderAfterPrecedence;
     private Numeric borderBeforePrecedence;
     private Numeric borderEndPrecedence;
     private Numeric borderStartPrecedence;
-    private String ptr;
 
     ConditionalBorder borderBefore;             // CSOK: VisibilityModifier
     ConditionalBorder borderAfter;              // CSOK: VisibilityModifier
@@ -240,16 +238,6 @@ public abstract class TableFObj extends FObj implements StructurePointerProperty
         }
     }
 
-    @Override
-    public void setPtr(String ptr) {
-        this.ptr = ptr;
-    }
-
-    /** {@inheritDoc} */
-    public String getPtr() {
-        return ptr;
-    }
-
     /**
      * Prepares the borders of this element if the collapsing-border model is in use.
      * Conflict resolution with parent elements is done where applicable.
diff --git a/src/java/org/apache/fop/fo/properties/StructureTreeElementHolder.java b/src/java/org/apache/fop/fo/properties/StructureTreeElementHolder.java
new file mode 100644
index 000000000..6fbb608de
--- /dev/null
+++ b/src/java/org/apache/fop/fo/properties/StructureTreeElementHolder.java
@@ -0,0 +1,38 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* $Id$ */
+
+package org.apache.fop.fo.properties;
+
+import org.apache.fop.accessibility.StructureTreeElement;
+
+/**
+ * Implementations of this interface can return the element in the document's
+ * structure tree that they resulted into. Used for tagged PDF and other formats
+ * that support a structure tree in addition to paged content.
+ */
+public interface StructureTreeElementHolder {
+
+    /**
+     * Returns the element in the document's structure tree that corresponds to this instance.
+     *
+     * @return a structure tree element
+     */
+    StructureTreeElement getStructureTreeElement();
+
+}
diff --git a/src/java/org/apache/fop/layoutmgr/BlockLayoutManager.java b/src/java/org/apache/fop/layoutmgr/BlockLayoutManager.java
index b748c2152..ed2ea4ee9 100644
--- a/src/java/org/apache/fop/layoutmgr/BlockLayoutManager.java
+++ b/src/java/org/apache/fop/layoutmgr/BlockLayoutManager.java
@@ -329,7 +329,6 @@ public class BlockLayoutManager extends BlockStackingLayoutManager
 
         addMarkersToPage(false, isFirst(firstPos), isLast(lastPos));
 
-        TraitSetter.addPtr(curBlockArea, getBlockFO().getPtr());  // used for accessibility
         TraitSetter.addSpaceBeforeAfter(curBlockArea, layoutContext.getSpaceAdjust(),
                 effSpaceBefore, effSpaceAfter);
         flush();
diff --git a/src/java/org/apache/fop/layoutmgr/TraitSetter.java b/src/java/org/apache/fop/layoutmgr/TraitSetter.java
index c0e451577..da548c23c 100644
--- a/src/java/org/apache/fop/layoutmgr/TraitSetter.java
+++ b/src/java/org/apache/fop/layoutmgr/TraitSetter.java
@@ -22,6 +22,7 @@ package org.apache.fop.layoutmgr;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
+import org.apache.fop.accessibility.StructureTreeElement;
 import org.apache.fop.area.Area;
 import org.apache.fop.area.Trait;
 import org.apache.fop.datatypes.LengthBase;
@@ -29,9 +30,9 @@ import org.apache.fop.datatypes.PercentBaseContext;
 import org.apache.fop.datatypes.SimplePercentBaseContext;
 import org.apache.fop.fo.Constants;
 import org.apache.fop.fo.properties.CommonBorderPaddingBackground;
+import org.apache.fop.fo.properties.CommonBorderPaddingBackground.BorderInfo;
 import org.apache.fop.fo.properties.CommonMarginBlock;
 import org.apache.fop.fo.properties.CommonTextDecoration;
-import org.apache.fop.fo.properties.CommonBorderPaddingBackground.BorderInfo;
 import org.apache.fop.fonts.Font;
 import org.apache.fop.traits.BorderProps;
 import org.apache.fop.traits.MinOptMax;
@@ -591,13 +592,14 @@ public final class TraitSetter {
     }
 
     /**
-     * Adds the ptr trait to the area.
+     * Sets the structure tree element associated to the given area.
+     *
      * @param area the area to set the traits on
-     * @param ptr string
+     * @param structureTreeElement the element the area is associated to in the document structure
      */
-    public static void addPtr(Area area, String ptr) {
-        if (ptr != null && ptr.length() > 0) {
-            area.addTrait(Trait.PTR, ptr);
+    public static void addStructureTreeElement(Area area, StructureTreeElement structureTreeElement) {
+        if (structureTreeElement != null) {
+            area.addTrait(Trait.STRUCTURE_TREE_ELEMENT, structureTreeElement);
         }
     }
 
diff --git a/src/java/org/apache/fop/layoutmgr/inline/AbstractGraphicsLayoutManager.java b/src/java/org/apache/fop/layoutmgr/inline/AbstractGraphicsLayoutManager.java
index 218497a53..8c797a48c 100644
--- a/src/java/org/apache/fop/layoutmgr/inline/AbstractGraphicsLayoutManager.java
+++ b/src/java/org/apache/fop/layoutmgr/inline/AbstractGraphicsLayoutManager.java
@@ -85,7 +85,7 @@ public abstract class AbstractGraphicsLayoutManager extends LeafNodeLayoutManage
         transferForeignAttributes(viewportArea);
 
         InlineViewport vp = new InlineViewport(viewportArea);
-        TraitSetter.addPtr(vp, fobj.getPtr());  // used for accessibility
+        TraitSetter.addStructureTreeElement(vp, fobj.getStructureTreeElement());
         TraitSetter.setProducerID(vp, fobj.getId());
         vp.setIPD(imageLayout.getViewportSize().width);
         vp.setBPD(imageLayout.getViewportSize().height);
diff --git a/src/java/org/apache/fop/layoutmgr/inline/AbstractPageNumberCitationLayoutManager.java b/src/java/org/apache/fop/layoutmgr/inline/AbstractPageNumberCitationLayoutManager.java
index e090fbae6..8c769924a 100644
--- a/src/java/org/apache/fop/layoutmgr/inline/AbstractPageNumberCitationLayoutManager.java
+++ b/src/java/org/apache/fop/layoutmgr/inline/AbstractPageNumberCitationLayoutManager.java
@@ -136,7 +136,7 @@ public abstract class AbstractPageNumberCitationLayoutManager extends LeafNodeLa
         text.setBaselineOffset(font.getAscender());
         TraitSetter.addFontTraits(text, font);
         text.addTrait(Trait.COLOR, fobj.getColor());
-        TraitSetter.addPtr(text, fobj.getPtr());   // used for accessibility
+        TraitSetter.addStructureTreeElement(text, fobj.getStructureTreeElement());
         TraitSetter.addTextDecoration(text, fobj.getTextDecoration());
     }
 
diff --git a/src/java/org/apache/fop/layoutmgr/inline/BasicLinkLayoutManager.java b/src/java/org/apache/fop/layoutmgr/inline/BasicLinkLayoutManager.java
index 40c9a324e..1390c04d8 100644
--- a/src/java/org/apache/fop/layoutmgr/inline/BasicLinkLayoutManager.java
+++ b/src/java/org/apache/fop/layoutmgr/inline/BasicLinkLayoutManager.java
@@ -59,7 +59,7 @@ public class BasicLinkLayoutManager extends InlineLayoutManager {
     private void setupBasicLinkArea(InlineArea area) {
         BasicLink fobj = (BasicLink) this.fobj;
         // internal destinations take precedence:
-        TraitSetter.addPtr(area, fobj.getPtr()); // used for accessibility
+        TraitSetter.addStructureTreeElement(area, fobj.getStructureTreeElement());
         if (fobj.hasInternalDestination()) {
             String idref = fobj.getInternalDestination();
             PageSequenceLayoutManager pslm = getPSLM();
diff --git a/src/java/org/apache/fop/layoutmgr/inline/CharacterLayoutManager.java b/src/java/org/apache/fop/layoutmgr/inline/CharacterLayoutManager.java
index 2178b2e77..4877ff9bd 100644
--- a/src/java/org/apache/fop/layoutmgr/inline/CharacterLayoutManager.java
+++ b/src/java/org/apache/fop/layoutmgr/inline/CharacterLayoutManager.java
@@ -87,7 +87,7 @@ public class CharacterLayoutManager extends LeafNodeLayoutManager {
         }
         TraitSetter.setProducerID(text, node.getId());
         TraitSetter.addTextDecoration(text, node.getTextDecoration());
-        TraitSetter.addPtr(text, node.getPtr()); // used for accessibility
+        TraitSetter.addStructureTreeElement(text, node.getStructureTreeElement());
         return text;
     }
 
diff --git a/src/java/org/apache/fop/layoutmgr/inline/PageNumberLayoutManager.java b/src/java/org/apache/fop/layoutmgr/inline/PageNumberLayoutManager.java
index d8cfe6cda..4b7289b37 100644
--- a/src/java/org/apache/fop/layoutmgr/inline/PageNumberLayoutManager.java
+++ b/src/java/org/apache/fop/layoutmgr/inline/PageNumberLayoutManager.java
@@ -19,13 +19,13 @@
 
 package org.apache.fop.layoutmgr.inline;
 
+import org.apache.fop.area.Trait;
+import org.apache.fop.area.inline.InlineArea;
+import org.apache.fop.area.inline.TextArea;
 import org.apache.fop.fo.flow.PageNumber;
 import org.apache.fop.fonts.Font;
 import org.apache.fop.fonts.FontInfo;
 import org.apache.fop.fonts.FontTriplet;
-import org.apache.fop.area.inline.InlineArea;
-import org.apache.fop.area.inline.TextArea;
-import org.apache.fop.area.Trait;
 import org.apache.fop.layoutmgr.LayoutContext;
 import org.apache.fop.layoutmgr.TraitSetter;
 import org.apache.fop.traits.MinOptMax;
@@ -85,7 +85,7 @@ public class PageNumberLayoutManager extends LeafNodeLayoutManager {
         text.setBaselineOffset(font.getAscender());
         TraitSetter.addFontTraits(text, font);
         text.addTrait(Trait.COLOR, fobj.getColor());
-        TraitSetter.addPtr(text, fobj.getPtr()); // used for accessibility
+        TraitSetter.addStructureTreeElement(text, fobj.getStructureTreeElement());
         TraitSetter.addTextDecoration(text, fobj.getTextDecoration());
 
         return text;
diff --git a/src/java/org/apache/fop/layoutmgr/inline/TextLayoutManager.java b/src/java/org/apache/fop/layoutmgr/inline/TextLayoutManager.java
index 81240dec0..8767fe296 100644
--- a/src/java/org/apache/fop/layoutmgr/inline/TextLayoutManager.java
+++ b/src/java/org/apache/fop/layoutmgr/inline/TextLayoutManager.java
@@ -31,8 +31,6 @@ import org.apache.fop.area.Trait;
 import org.apache.fop.area.inline.TextArea;
 import org.apache.fop.fo.Constants;
 import org.apache.fop.fo.FOText;
-import org.apache.fop.fo.FObj;
-import org.apache.fop.fo.properties.StructurePointerPropertySet;
 import org.apache.fop.fonts.Font;
 import org.apache.fop.fonts.FontSelector;
 import org.apache.fop.layoutmgr.InlineKnuthSequence;
@@ -438,7 +436,7 @@ public class TextLayoutManager extends LeafNodeLayoutManager {
             setText();
             TraitSetter.addFontTraits(textArea, font);
             textArea.addTrait(Trait.COLOR, foText.getColor());
-            TraitSetter.addPtr(textArea, getPtr()); // used for accessibility
+            TraitSetter.addStructureTreeElement(textArea, foText.getStructureTreeElement());
             TraitSetter.addTextDecoration(textArea, foText.getTextDecoration());
             TraitSetter.addFontTraits(textArea, font);
             return textArea;
@@ -577,20 +575,6 @@ public class TextLayoutManager extends LeafNodeLayoutManager {
         }
     }
 
-    /**
-     * used for accessibility
-     * @return ptr of fobj
-     */
-    private String getPtr() {
-        FObj fobj = parentLayoutManager.getFObj();
-        if (fobj instanceof StructurePointerPropertySet) {
-            return (((StructurePointerPropertySet) fobj).getPtr());
-        } else {
-            //No structure pointer applicable
-            return null;
-        }
-    }
-
     private AreaInfo getAreaInfo(int index) {
         return (AreaInfo) areaInfos.get(index);
     }
diff --git a/src/java/org/apache/fop/pdf/PDFStructElem.java b/src/java/org/apache/fop/pdf/PDFStructElem.java
index 6dfb0dc95..44622638d 100644
--- a/src/java/org/apache/fop/pdf/PDFStructElem.java
+++ b/src/java/org/apache/fop/pdf/PDFStructElem.java
@@ -19,18 +19,29 @@
 
 package org.apache.fop.pdf;
 
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.Writer;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Locale;
 
+import org.apache.fop.accessibility.StructureTreeElement;
 import org.apache.fop.util.LanguageTags;
 
 /**
  * Class representing a PDF Structure Element.
  */
-public class PDFStructElem extends PDFDictionary {
+public class PDFStructElem extends PDFDictionary implements StructureTreeElement {
 
     private PDFStructElem parentElement;
 
     /**
+     * Elements to be added to the kids array.
+     */
+    protected List<PDFObject> kids;
+
+    /**
      * Creates a new structure element.
      *
      * @param parent parent of this element
@@ -57,21 +68,12 @@ public class PDFStructElem extends PDFDictionary {
 
     /** {@inheritDoc} */
     public void setParent(PDFObject parent) {
-        if (parent != null) {
+        if (parent != null && parent.hasObjectNumber()) {
            put("P", new PDFReference(parent));
         }
     }
 
     /**
-     * Returns the kids of this structure element.
-     *
-     * @return the value of the K entry
-     */
-    private PDFArray getKids() {
-        return (PDFArray) get("K");
-    }
-
-    /**
      * Add a kid to this structure element. This element will then add itself to
      * its parent structure element if it has not already, and so will the
      * parent, and so on.
@@ -79,24 +81,10 @@ public class PDFStructElem extends PDFDictionary {
      * @param kid element to be added
      */
     public void addKid(PDFObject kid) {
-        PDFArray kids = getKids();
         if (kids == null) {
-            kids = new PDFArray();
-            put("K", kids);
+            kids = new ArrayList<PDFObject>();
         }
         kids.add(kid);
-        joinHierarchy();
-    }
-
-    private boolean containsKid(PDFObject kid) {
-        PDFArray kids = getKids();
-        return kids != null && kids.contains(kid);
-    }
-
-    private void joinHierarchy() {
-        if (parentElement != null && !parentElement.containsKid(this)) {
-            parentElement.addKid(this);
-        }
     }
 
     /**
@@ -109,7 +97,6 @@ public class PDFStructElem extends PDFDictionary {
      */
     public void setMCIDKid(int mcid) {
         put("K", mcid);
-        joinHierarchy();
     }
 
     /**
@@ -127,7 +114,7 @@ public class PDFStructElem extends PDFDictionary {
      * @return the value of the S entry
      */
     public PDFName getStructureType() {
-        return (PDFName)get("S");
+        return (PDFName) get("S");
     }
 
     /**
@@ -154,6 +141,63 @@ public class PDFStructElem extends PDFDictionary {
      * @return the value of the Lang entry (<code>null</code> if no language was specified)
      */
     public String getLanguage() {
-        return (String)get("Lang");
+        return (String) get("Lang");
+    }
+
+    @Override
+    protected void writeDictionary(OutputStream out, Writer writer) throws IOException {
+        attachKids();
+        super.writeDictionary(out, writer);
+    }
+
+    /**
+     * Attaches all valid kids to the kids array.
+     *
+     * @return true iff 1+ kids were added to the kids array
+     */
+    protected boolean attachKids() {
+        List<PDFObject> validKids = new ArrayList<PDFObject>();
+        if (kids != null) {
+            for (PDFObject kid : kids) {
+                if (kid instanceof Placeholder)  {
+                    if (((Placeholder) kid).attachKids()) {
+                        validKids.add(kid);
+                    }
+                } else {
+                    validKids.add(kid);
+                }
+            }
+        }
+        boolean kidsAttached = !validKids.isEmpty();
+        if (kidsAttached) {
+            PDFArray array = new PDFArray();
+            for (PDFObject ob : validKids) {
+                array.add(ob);
+            }
+            put("K", array);
+        }
+        return kidsAttached;
     }
+
+    public static class Placeholder extends PDFStructElem {
+
+        @Override
+        public void outputInline(OutputStream out, Writer writer) throws IOException {
+            if (kids != null) {
+                assert kids.size() > 0;
+                for (int i = 0; i < kids.size(); i++) {
+                    if (i > 0) {
+                        writer.write(' ');
+                    }
+                    Object obj = kids.get(i);
+                    formatObject(obj, out, writer);
+                }
+            }
+        }
+
+        public Placeholder(PDFObject parent, String name) {
+            super(parent, new PDFName(name));
+        }
+    }
+
 }
diff --git a/src/java/org/apache/fop/render/intermediate/IFContext.java b/src/java/org/apache/fop/render/intermediate/IFContext.java
index b8be97253..c59a02ba8 100644
--- a/src/java/org/apache/fop/render/intermediate/IFContext.java
+++ b/src/java/org/apache/fop/render/intermediate/IFContext.java
@@ -25,6 +25,7 @@ import java.util.Map;
 
 import org.apache.xmlgraphics.util.QName;
 
+import org.apache.fop.accessibility.StructureTreeElement;
 import org.apache.fop.apps.FOUserAgent;
 
 /**
@@ -46,7 +47,7 @@ public class IFContext {
 
     private Locale language;
 
-    private String structurePointer;
+    private StructureTreeElement structureTreeElement;
 
     private String id = "";
 
@@ -132,29 +133,31 @@ public class IFContext {
     }
 
     /**
-     * Sets the structure pointer for the following painted marks. This method is used when
-     * accessibility features are enabled.
-     * @param ptr the structure pointer
+     * Sets the structure tree element to which the subsequently painted marks
+     * will correspond. This method is used when accessibility features are
+     * enabled.
+     *
+     * @param structureTreeElement the structure tree element
      */
-    public void setStructurePointer(String ptr) {
-        this.structurePointer = ptr;
+    public void setStructureTreeElement(StructureTreeElement structureTreeElement) {
+        this.structureTreeElement = structureTreeElement;
     }
 
     /**
-     * Resets the current structure pointer.
-     * @see #setStructurePointer(String)
+     * Resets the current structure tree element.
+     * @see #setStructureTreeElement(String)
      */
-    public void resetStructurePointer() {
-        setStructurePointer(null);
+    public void resetStructureTreeElement() {
+        setStructureTreeElement(null);
     }
 
     /**
-     * Returns the current structure pointer.
-     * @return the structure pointer (or null if no pointer is active)
-     * @see #setStructurePointer(String)
+     * Returns the current structure tree element.
+     * @return the structure tree element (or null if no element is active)
+     * @see #setStructureTreeElement(String)
      */
-    public String getStructurePointer() {
-        return this.structurePointer;
+    public StructureTreeElement getStructureTreeElement() {
+        return this.structureTreeElement;
     }
 
     /**
diff --git a/src/java/org/apache/fop/render/intermediate/IFParser.java b/src/java/org/apache/fop/render/intermediate/IFParser.java
index 8f0bb88ec..1a384c6e9 100644
--- a/src/java/org/apache/fop/render/intermediate/IFParser.java
+++ b/src/java/org/apache/fop/render/intermediate/IFParser.java
@@ -49,11 +49,13 @@ import org.apache.commons.logging.LogFactory;
 import org.apache.xmlgraphics.util.QName;
 
 import org.apache.fop.accessibility.AccessibilityEventProducer;
+import org.apache.fop.accessibility.StructureTreeElement;
 import org.apache.fop.accessibility.StructureTreeEventHandler;
 import org.apache.fop.apps.FOUserAgent;
 import org.apache.fop.fo.ElementMapping;
 import org.apache.fop.fo.ElementMappingRegistry;
 import org.apache.fop.fo.expr.PropertyException;
+import org.apache.fop.fo.extensions.InternalElementMapping;
 import org.apache.fop.render.intermediate.extensions.DocumentNavigationExtensionConstants;
 import org.apache.fop.render.intermediate.extensions.DocumentNavigationHandler;
 import org.apache.fop.traits.BorderProps;
@@ -158,6 +160,9 @@ public class IFParser implements IFConstants {
 
         private Attributes pageSequenceAttributes;
 
+        private Map<String, StructureTreeElement> structureTreeElements =
+                new HashMap<String, StructureTreeElement>();
+
         private final class StructureTreeHandler extends DefaultHandler {
 
             private final StructureTreeEventHandler structureTreeEventHandler;
@@ -177,7 +182,23 @@ public class IFParser implements IFConstants {
             public void startElement(String uri, String localName, String qName,
                     Attributes attributes) throws SAXException {
                 if (!"structure-tree".equals(localName)) {
-                    structureTreeEventHandler.startNode(localName, attributes);
+                    if (localName.equals("marked-content")) {
+                        localName = "#PCDATA";
+                    }
+                    String structID = attributes.getValue(InternalElementMapping.URI,
+                            InternalElementMapping.STRUCT_ID);
+                    if (structID == null) {
+                        structureTreeEventHandler.startNode(localName, attributes);
+                    } else if (localName.equals("external-graphic")
+                            || localName.equals("instream-foreign-object")) {
+                        StructureTreeElement structureTreeElement =
+                            structureTreeEventHandler.startImageNode(localName, attributes);
+                        structureTreeElements.put(structID, structureTreeElement);
+                    } else {
+                        StructureTreeElement structureTreeElement =
+                            structureTreeEventHandler.startReferencedNode(localName, attributes);
+                        structureTreeElements.put(structID, structureTreeElement);
+                    }
                 }
             }
 
@@ -225,14 +246,6 @@ public class IFParser implements IFConstants {
             documentHandler.getContext().resetForeignAttributes();
         }
 
-        private void establishStructurePointer(String ptr) {
-            documentHandler.getContext().setStructurePointer(ptr);
-        }
-
-        private void resetStructurePointer() {
-            documentHandler.getContext().resetStructurePointer();
-        }
-
         /** {@inheritDoc} */
         public void startElement(String uri, String localName, String qName, Attributes attributes)
                     throws SAXException {
@@ -276,7 +289,7 @@ public class IFParser implements IFConstants {
                 } else if (DocumentNavigationExtensionConstants.NAMESPACE.equals(uri)) {
                     if (this.navParser == null) {
                         this.navParser = new DocumentNavigationHandler(
-                                this.documentHandler.getDocumentNavigationHandler());
+                                this.documentHandler.getDocumentNavigationHandler(), structureTreeElements);
                     }
                     delegate = this.navParser;
                     delegateDepth++;
@@ -604,9 +617,9 @@ public class IFParser implements IFConstants {
                 s = lastAttributes.getValue("word-spacing");
                 int wordSpacing = (s != null ? Integer.parseInt(s) : 0);
                 int[] dx = XMLUtil.getAttributeAsIntArray(lastAttributes, "dx");
-                setStructurePointer(lastAttributes);
+                establishStructureTreeElement(lastAttributes);
                 painter.drawText(x, y, letterSpacing, wordSpacing, dx, content.toString());
-                resetStructurePointer();
+                resetStructureTreeElement();
             }
 
             public boolean ignoreCharacters() {
@@ -701,7 +714,7 @@ public class IFParser implements IFConstants {
                 int height = Integer.parseInt(lastAttributes.getValue("height"));
                 Map<QName, String> foreignAttributes = getForeignAttributes(lastAttributes);
                 establishForeignAttributes(foreignAttributes);
-                setStructurePointer(lastAttributes);
+                establishStructureTreeElement(lastAttributes);
                 if (foreignObject != null) {
                     painter.drawImage(foreignObject,
                             new Rectangle(x, y, width, height));
@@ -715,7 +728,7 @@ public class IFParser implements IFConstants {
                     painter.drawImage(uri, new Rectangle(x, y, width, height));
                 }
                 resetForeignAttributes();
-                resetStructurePointer();
+                resetStructureTreeElement();
                 inForeignObject = false;
             }
 
@@ -769,13 +782,20 @@ public class IFParser implements IFConstants {
             return foreignAttributes;
         }
 
-        private void setStructurePointer(Attributes attributes) {
-            String ptr = attributes.getValue("ptr");
-            if (ptr != null && ptr.length() > 0) {
-                establishStructurePointer(ptr);
+        private void establishStructureTreeElement(Attributes attributes) {
+            String structRef = attributes.getValue(InternalElementMapping.URI,
+                    InternalElementMapping.STRUCT_REF);
+            if (structRef != null && structRef.length() > 0) {
+                assert structureTreeElements.containsKey(structRef);
+                StructureTreeElement structureTreeElement = structureTreeElements.get(structRef);
+                documentHandler.getContext().setStructureTreeElement(structureTreeElement);
             }
         }
 
+        private void resetStructureTreeElement() {
+            documentHandler.getContext().resetStructureTreeElement();
+        }
+
         /** {@inheritDoc} */
         public void characters(char[] ch, int start, int length) throws SAXException {
             if (delegate != null) {
diff --git a/src/java/org/apache/fop/render/intermediate/IFRenderer.java b/src/java/org/apache/fop/render/intermediate/IFRenderer.java
index d217646f6..a2d8a0bea 100644
--- a/src/java/org/apache/fop/render/intermediate/IFRenderer.java
+++ b/src/java/org/apache/fop/render/intermediate/IFRenderer.java
@@ -50,6 +50,7 @@ import org.apache.xmlgraphics.xmp.schemas.XMPBasicAdapter;
 import org.apache.xmlgraphics.xmp.schemas.XMPBasicSchema;
 
 import org.apache.fop.Version;
+import org.apache.fop.accessibility.StructureTreeElement;
 import org.apache.fop.apps.FOPException;
 import org.apache.fop.apps.FOUserAgent;
 import org.apache.fop.apps.MimeConstants;
@@ -629,12 +630,12 @@ public class IFRenderer extends AbstractPathOrientedRenderer {
         documentHandler.getContext().resetForeignAttributes();
     }
 
-    private void establishStructurePointer(String ptr) {
-        documentHandler.getContext().setStructurePointer(ptr);
+    private void establishStructureTreeElement(StructureTreeElement structureTreeElement) {
+        documentHandler.getContext().setStructureTreeElement(structureTreeElement);
     }
 
     private void resetStructurePointer() {
-        documentHandler.getContext().resetStructurePointer();
+        documentHandler.getContext().resetStructureTreeElement();
     }
 
     /** {@inheritDoc} */
@@ -851,8 +852,9 @@ public class IFRenderer extends AbstractPathOrientedRenderer {
 
     /** {@inheritDoc} */
     public void renderInlineViewport(InlineViewport viewport) {
-        String ptr = (String) viewport.getTrait(Trait.PTR);
-        establishStructurePointer(ptr);
+        StructureTreeElement structElem =
+                (StructureTreeElement) viewport.getTrait(Trait.STRUCTURE_TREE_ELEMENT);
+        establishStructureTreeElement(structElem);
         pushdID(viewport);
         Dimension dim = new Dimension(viewport.getIPD(), viewport.getBPD());
         viewportDimensionStack.push(dim);
@@ -912,7 +914,6 @@ public class IFRenderer extends AbstractPathOrientedRenderer {
         // stuff we only need if a link must be created:
         Rectangle ipRect = null;
         AbstractAction action = null;
-        String ptr = (String) ip.getTrait(Trait.PTR); // used for accessibility
         // make sure the rect is determined *before* calling super!
         int ipp = currentIPPosition;
         int bpp = currentBPPosition + ip.getOffset();
@@ -956,7 +957,9 @@ public class IFRenderer extends AbstractPathOrientedRenderer {
 
         // warn if link trait found but not allowed, else create link
         if (linkTraitFound) {
-            action.setStructurePointer(ptr);  // used for accessibility
+            StructureTreeElement structElem =
+                    (StructureTreeElement) ip.getTrait(Trait.STRUCTURE_TREE_ELEMENT);
+            action.setStructureTreeElement(structElem);
             Link link = new Link(action, ipRect);
             this.deferredLinks.add(link);
         }
@@ -1009,8 +1012,8 @@ public class IFRenderer extends AbstractPathOrientedRenderer {
 
         String fontName = getInternalFontNameForArea(text);
         int size = ((Integer) text.getTrait(Trait.FONT_SIZE)).intValue();
-        String ptr = (String)text.getTrait(Trait.PTR); // used for accessibility
-        establishStructurePointer(ptr);
+        StructureTreeElement structElem = (StructureTreeElement) text.getTrait(Trait.STRUCTURE_TREE_ELEMENT);
+        establishStructureTreeElement(structElem);
 
         // This assumes that *all* CIDFonts use a /ToUnicode mapping
         Typeface tf = getTypeface(fontName);
diff --git a/src/java/org/apache/fop/render/intermediate/IFSerializer.java b/src/java/org/apache/fop/render/intermediate/IFSerializer.java
index a4431b972..c6bf9af9e 100644
--- a/src/java/org/apache/fop/render/intermediate/IFSerializer.java
+++ b/src/java/org/apache/fop/render/intermediate/IFSerializer.java
@@ -38,9 +38,11 @@ import org.apache.xmlgraphics.util.QName;
 import org.apache.xmlgraphics.util.XMLizable;
 
 import org.apache.fop.accessibility.StructureTreeEventHandler;
+import org.apache.fop.fo.extensions.InternalElementMapping;
 import org.apache.fop.fonts.FontInfo;
 import org.apache.fop.render.PrintRendererConfigurator;
 import org.apache.fop.render.RenderingContext;
+import org.apache.fop.render.intermediate.IFStructureTreeBuilder.IFStructureTreeElement;
 import org.apache.fop.render.intermediate.extensions.AbstractAction;
 import org.apache.fop.render.intermediate.extensions.Bookmark;
 import org.apache.fop.render.intermediate.extensions.BookmarkTree;
@@ -163,6 +165,7 @@ public class IFSerializer extends AbstractXMLWritingIFDocumentHandler
             handler.startPrefixMapping(XLINK_PREFIX, XLINK_NAMESPACE);
             handler.startPrefixMapping(DocumentNavigationExtensionConstants.PREFIX,
                     DocumentNavigationExtensionConstants.NAMESPACE);
+            handler.startPrefixMapping(InternalElementMapping.STANDARD_PREFIX, InternalElementMapping.URI);
             handler.startElement(EL_DOCUMENT);
         } catch (SAXException e) {
             throw new IFException("SAX error in startDocument()", e);
@@ -439,7 +442,7 @@ public class IFSerializer extends AbstractXMLWritingIFDocumentHandler
             addAttribute(atts, "width", Integer.toString(rect.width));
             addAttribute(atts, "height", Integer.toString(rect.height));
             addForeignAttributes(atts);
-            addStructurePointerAttribute(atts);
+            addStructureReference(atts);
             handler.element(EL_IMAGE, atts);
         } catch (SAXException e) {
             throw new IFException("SAX error in startGroup()", e);
@@ -467,7 +470,7 @@ public class IFSerializer extends AbstractXMLWritingIFDocumentHandler
             addAttribute(atts, "width", Integer.toString(rect.width));
             addAttribute(atts, "height", Integer.toString(rect.height));
             addForeignAttributes(atts);
-            addStructurePointerAttribute(atts);
+            addStructureReference(atts);
             handler.startElement(EL_IMAGE, atts);
             new DOM2SAX(handler).writeDocument(doc, true);
             handler.endElement(EL_IMAGE);
@@ -582,7 +585,7 @@ public class IFSerializer extends AbstractXMLWritingIFDocumentHandler
             if (dx != null) {
                 addAttribute(atts, "dx", IFUtil.toString(dx));
             }
-            addStructurePointerAttribute(atts);
+            addStructureReference(atts);
             handler.startElement(EL_TEXT, atts);
             char[] chars = text.toCharArray();
             handler.characters(chars, 0, chars.length);
@@ -682,13 +685,22 @@ public class IFSerializer extends AbstractXMLWritingIFDocumentHandler
         XMLUtil.addAttribute(atts, localName, value);
     }
 
-    private void addStructurePointerAttribute(AttributesImpl atts) {
-        String ptr = getContext().getStructurePointer();
-        if (ptr != null) {
-            addAttribute(atts, "ptr", ptr);
+    private void addStructureReference(AttributesImpl atts) {
+        IFStructureTreeElement structureTreeElement =
+                (IFStructureTreeElement) getContext().getStructureTreeElement();
+        if (structureTreeElement != null) {
+            addStructRefAttribute(atts, structureTreeElement.id);
         }
     }
 
+    private void addStructRefAttribute(AttributesImpl atts, String id) {
+        atts.addAttribute(InternalElementMapping.URI,
+                InternalElementMapping.STRUCT_REF,
+                InternalElementMapping.STANDARD_PREFIX + ":" + InternalElementMapping.STRUCT_REF,
+                XMLConstants.CDATA,
+                id);
+    }
+
     private void addID() throws SAXException {
         String id = getContext().getID();
         if (!currentID.equals(id)) {
@@ -773,7 +785,8 @@ public class IFSerializer extends AbstractXMLWritingIFDocumentHandler
         atts.addAttribute(null, "rect", "rect",
                 XMLConstants.CDATA, IFUtil.toString(link.getTargetRect()));
         if (getUserAgent().isAccessibilityEnabled()) {
-            addAttribute(atts, "ptr", link.getAction().getStructurePointer());
+            addStructRefAttribute(atts,
+                    ((IFStructureTreeElement) link.getAction().getStructureTreeElement()).id);
         }
         try {
             handler.startElement(DocumentNavigationExtensionConstants.LINK, atts);
diff --git a/src/java/org/apache/fop/render/intermediate/IFStructureTreeBuilder.java b/src/java/org/apache/fop/render/intermediate/IFStructureTreeBuilder.java
index 66457681f..b78ae35bc 100644
--- a/src/java/org/apache/fop/render/intermediate/IFStructureTreeBuilder.java
+++ b/src/java/org/apache/fop/render/intermediate/IFStructureTreeBuilder.java
@@ -26,10 +26,14 @@ import java.util.Locale;
 import org.xml.sax.Attributes;
 import org.xml.sax.ContentHandler;
 import org.xml.sax.SAXException;
+import org.xml.sax.helpers.AttributesImpl;
 import org.xml.sax.helpers.DefaultHandler;
 
 import org.apache.fop.accessibility.StructureTree2SAXEventAdapter;
+import org.apache.fop.accessibility.StructureTreeElement;
 import org.apache.fop.accessibility.StructureTreeEventHandler;
+import org.apache.fop.fo.extensions.InternalElementMapping;
+import org.apache.fop.util.XMLUtil;
 
 /**
  * Saves structure tree events as SAX events in order to replay them when it's
@@ -37,42 +41,17 @@ import org.apache.fop.accessibility.StructureTreeEventHandler;
  */
 final class IFStructureTreeBuilder implements StructureTreeEventHandler {
 
-    private StructureTreeEventHandler delegate;
-
-    private final List<SAXEventRecorder> pageSequenceEventRecorders = new ArrayList<SAXEventRecorder>();
-
-    /**
-     * Replay SAX events for a page sequence.
-     * @param handler The handler that receives SAX events
-     * @param pageSequenceIndex The index of the page sequence
-     * @throws SAXException
-     */
-    public void replayEventsForPageSequence(ContentHandler handler,
-            int pageSequenceIndex) throws SAXException {
-        pageSequenceEventRecorders.get(pageSequenceIndex).replay(handler);
-    }
-
-    /** {@inheritDoc} */
-    public void startPageSequence(Locale locale) {
-        SAXEventRecorder eventRecorder = new SAXEventRecorder();
-        pageSequenceEventRecorders.add(eventRecorder);
-        delegate = StructureTree2SAXEventAdapter.newInstance(eventRecorder);
-        delegate.startPageSequence(locale);
-    }
+    static final class IFStructureTreeElement implements StructureTreeElement {
 
-    /** {@inheritDoc} */
-    public void endPageSequence() {
-         delegate.endPageSequence();
-    }
+        final String id;
 
-    /** {@inheritDoc} */
-    public void startNode(String name, Attributes attributes) {
-        delegate.startNode(name, attributes);
-    }
+        IFStructureTreeElement() {
+            this.id = null;
+        }
 
-    /** {@inheritDoc} */
-    public void endNode(String name) {
-        delegate.endNode(name);
+        IFStructureTreeElement(String id) {
+            this.id = id;
+        }
     }
 
     /** A SAX handler that records events to replay them later. */
@@ -159,22 +138,22 @@ final class IFStructureTreeBuilder implements StructureTreeEventHandler {
         public void startElement(String uri, String localName, String qName,
                 Attributes attributes) throws SAXException {
             events.add(new StartElement(uri, localName, qName, attributes));
-        };
+        }
 
         @Override
         public void endElement(String uri, String localName, String qName) throws SAXException {
             events.add(new EndElement(uri, localName, qName));
-        };
+        }
 
         @Override
         public void startPrefixMapping(String prefix, String uri) throws SAXException {
             events.add(new StartPrefixMapping(prefix, uri));
-        };
+        }
 
         @Override
         public void endPrefixMapping(String prefix) throws SAXException {
             events.add(new EndPrefixMapping(prefix));
-        };
+        }
 
         /**
          * Replays the recorded events.
@@ -187,4 +166,69 @@ final class IFStructureTreeBuilder implements StructureTreeEventHandler {
             }
         }
     }
+
+    private StructureTreeEventHandler delegate;
+
+    private final List<SAXEventRecorder> pageSequenceEventRecorders = new ArrayList<SAXEventRecorder>();
+
+    private int idCounter;
+
+    /**
+     * Replay SAX events for a page sequence.
+     * @param handler The handler that receives SAX events
+     * @param pageSequenceIndex The index of the page sequence
+     * @throws SAXException
+     */
+    public void replayEventsForPageSequence(ContentHandler handler,
+            int pageSequenceIndex) throws SAXException {
+        pageSequenceEventRecorders.get(pageSequenceIndex).replay(handler);
+    }
+
+    public void startPageSequence(Locale locale) {
+        SAXEventRecorder eventRecorder = new SAXEventRecorder();
+        pageSequenceEventRecorders.add(eventRecorder);
+        delegate = StructureTree2SAXEventAdapter.newInstance(eventRecorder);
+        delegate.startPageSequence(locale);
+    }
+
+    public void endPageSequence() {
+         delegate.endPageSequence();
+    }
+
+    public StructureTreeElement startNode(String name, Attributes attributes) {
+        delegate.startNode(name, attributes);
+        return new IFStructureTreeElement();
+    }
+
+    public void endNode(String name) {
+        delegate.endNode(name);
+    }
+
+    public StructureTreeElement startImageNode(String name, Attributes attributes) {
+        String id = getNextID();
+        AttributesImpl atts = addIDAttribute(attributes, id);
+        delegate.startImageNode(name, atts);
+        return new IFStructureTreeElement(id);
+    }
+
+    public StructureTreeElement startReferencedNode(String name, Attributes attributes) {
+        String id = getNextID();
+        AttributesImpl atts = addIDAttribute(attributes, id);
+        delegate.startReferencedNode(name, atts);
+        return new IFStructureTreeElement(id);
+    }
+
+    private String getNextID() {
+        return Integer.toHexString(idCounter++);
+    }
+
+    private AttributesImpl addIDAttribute(Attributes attributes, String id) {
+        AttributesImpl atts = new AttributesImpl(attributes);
+        atts.addAttribute(InternalElementMapping.URI,
+                InternalElementMapping.STRUCT_ID,
+                InternalElementMapping.STANDARD_PREFIX + ":" + InternalElementMapping.STRUCT_ID,
+                XMLUtil.CDATA,
+                id);
+        return atts;
+    }
 }
diff --git a/src/java/org/apache/fop/render/intermediate/extensions/AbstractAction.java b/src/java/org/apache/fop/render/intermediate/extensions/AbstractAction.java
index 340b2e068..a2595d320 100644
--- a/src/java/org/apache/fop/render/intermediate/extensions/AbstractAction.java
+++ b/src/java/org/apache/fop/render/intermediate/extensions/AbstractAction.java
@@ -21,13 +21,15 @@ package org.apache.fop.render.intermediate.extensions;
 
 import org.apache.xmlgraphics.util.XMLizable;
 
+import org.apache.fop.accessibility.StructureTreeElement;
+
 /**
  * Abstract base class for document actions, like "go-to" actions with absolute page coordinates.
  */
 public abstract class AbstractAction implements XMLizable {
 
     private String id;
-    private String structurePointer;
+    private StructureTreeElement structureTreeElement;
 
     /**
      * Sets an ID to make the action referencable.
@@ -47,18 +49,18 @@ public abstract class AbstractAction implements XMLizable {
 
     /**
      * Sets the structure element corresponding to this action.
-     * @param structurePointer a reference to the structure element
+     * @param structureTreeElement a reference to the structure element
      */
-    public void setStructurePointer(String structurePointer) {
-        this.structurePointer = structurePointer;
+    public void setStructureTreeElement(StructureTreeElement structureTreeElement) {
+        this.structureTreeElement = structureTreeElement;
     }
 
     /**
      * Returns the structure element corresponding to this action.
      * @return the reference to the structure element
      */
-    public String getStructurePointer() {
-        return structurePointer;
+    public StructureTreeElement getStructureTreeElement() {
+        return structureTreeElement;
     }
 
     /**
diff --git a/src/java/org/apache/fop/render/intermediate/extensions/DocumentNavigationHandler.java b/src/java/org/apache/fop/render/intermediate/extensions/DocumentNavigationHandler.java
index 1e613d7eb..693497b73 100644
--- a/src/java/org/apache/fop/render/intermediate/extensions/DocumentNavigationHandler.java
+++ b/src/java/org/apache/fop/render/intermediate/extensions/DocumentNavigationHandler.java
@@ -21,6 +21,7 @@ package org.apache.fop.render.intermediate.extensions;
 
 import java.awt.Point;
 import java.awt.Rectangle;
+import java.util.Map;
 import java.util.Stack;
 
 import org.xml.sax.Attributes;
@@ -30,6 +31,8 @@ import org.xml.sax.helpers.DefaultHandler;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
+import org.apache.fop.accessibility.StructureTreeElement;
+import org.apache.fop.fo.extensions.InternalElementMapping;
 import org.apache.fop.render.intermediate.IFDocumentNavigationHandler;
 import org.apache.fop.render.intermediate.IFException;
 import org.apache.fop.util.XMLUtil;
@@ -48,14 +51,20 @@ public class DocumentNavigationHandler extends DefaultHandler
 
     private IFDocumentNavigationHandler navHandler;
 
-    private String structurePointer;
+    private StructureTreeElement structureTreeElement;
+
+    private Map<String, StructureTreeElement> structureTreeElements;
 
     /**
      * Main constructor.
      * @param navHandler the navigation handler that will receive the events
+     * @param structureTreeElements the elements representing the structure of the document
      */
-    public DocumentNavigationHandler(IFDocumentNavigationHandler navHandler) {
+    public DocumentNavigationHandler(IFDocumentNavigationHandler navHandler,
+            Map<String, StructureTreeElement> structureTreeElements) {
         this.navHandler = navHandler;
+        assert structureTreeElements != null;
+        this.structureTreeElements = structureTreeElements;
     }
 
     /** {@inheritDoc} */
@@ -98,7 +107,8 @@ public class DocumentNavigationHandler extends DefaultHandler
                     throw new SAXException(localName + " must be the root element!");
                 }
                 Rectangle targetRect = XMLUtil.getAttributeAsRectangle(attributes, "rect");
-                structurePointer = attributes.getValue("ptr");
+                structureTreeElement = structureTreeElements.get(
+                        attributes.getValue(InternalElementMapping.URI, InternalElementMapping.STRUCT_REF));
                 Link link = new Link(null, targetRect);
                 objectStack.push(link);
             } else if (GOTO_XY.getLocalName().equals(localName)) {
@@ -121,8 +131,8 @@ public class DocumentNavigationHandler extends DefaultHandler
                     }
                     action = new GoToXYAction(id, pageIndex, location);
                 }
-                if (structurePointer != null) {
-                    action.setStructurePointer(structurePointer);
+                if (structureTreeElement != null) {
+                    action.setStructureTreeElement(structureTreeElement);
                 }
                 objectStack.push(action);
             } else if (GOTO_URI.getLocalName().equals(localName)) {
@@ -134,8 +144,8 @@ public class DocumentNavigationHandler extends DefaultHandler
                 if (id != null) {
                     action.setID(id);
                 }
-                if (structurePointer != null) {
-                    action.setStructurePointer(structurePointer);
+                if (structureTreeElement != null) {
+                    action.setStructureTreeElement(structureTreeElement);
                 }
                 objectStack.push(action);
             } else {
diff --git a/src/java/org/apache/fop/render/pdf/PDFDocumentNavigationHandler.java b/src/java/org/apache/fop/render/pdf/PDFDocumentNavigationHandler.java
index c8fa481d4..2236778b5 100644
--- a/src/java/org/apache/fop/render/pdf/PDFDocumentNavigationHandler.java
+++ b/src/java/org/apache/fop/render/pdf/PDFDocumentNavigationHandler.java
@@ -31,6 +31,7 @@ import org.apache.fop.pdf.PDFFactory;
 import org.apache.fop.pdf.PDFGoTo;
 import org.apache.fop.pdf.PDFLink;
 import org.apache.fop.pdf.PDFOutline;
+import org.apache.fop.pdf.PDFStructElem;
 import org.apache.fop.render.intermediate.IFDocumentNavigationHandler;
 import org.apache.fop.render.intermediate.IFException;
 import org.apache.fop.render.intermediate.extensions.AbstractAction;
@@ -111,10 +112,9 @@ public class PDFDocumentNavigationHandler implements IFDocumentNavigationHandler
         PDFLink pdfLink = getPDFDoc().getFactory().makeLink(
                 targetRect2D, pdfAction);
         if (pdfLink != null) {
-            String ptr = link.getAction().getStructurePointer();
-            if (documentHandler.getUserAgent().isAccessibilityEnabled()
-                    && ptr != null && ptr.length() > 0) {
-                documentHandler.getLogicalStructureHandler().addLinkContentItem(pdfLink, ptr);
+            PDFStructElem structure = (PDFStructElem) link.getAction().getStructureTreeElement();
+            if (documentHandler.getUserAgent().isAccessibilityEnabled() && structure != null) {
+                documentHandler.getLogicalStructureHandler().addLinkContentItem(pdfLink, structure);
             }
             documentHandler.currentPage.addAnnotation(pdfLink);
         }
diff --git a/src/java/org/apache/fop/render/pdf/PDFLogicalStructureHandler.java b/src/java/org/apache/fop/render/pdf/PDFLogicalStructureHandler.java
index d49ef4a3e..88a6e9c22 100644
--- a/src/java/org/apache/fop/render/pdf/PDFLogicalStructureHandler.java
+++ b/src/java/org/apache/fop/render/pdf/PDFLogicalStructureHandler.java
@@ -19,9 +19,7 @@
 
 package org.apache.fop.render.pdf;
 
-import java.util.HashMap;
 import java.util.Locale;
-import java.util.Map;
 
 import org.apache.fop.pdf.PDFArray;
 import org.apache.fop.pdf.PDFDictionary;
@@ -47,11 +45,6 @@ class PDFLogicalStructureHandler {
 
     private final PDFDocument pdfDoc;
 
-    /**
-     * Map of references to the corresponding structure elements.
-     */
-    private final Map<String, PDFStructElem> structTreeMap = new HashMap<String, PDFStructElem>();
-
     private final PDFParentTree parentTree = new PDFParentTree();
 
     private int parentTreeKey;
@@ -151,100 +144,79 @@ class PDFLogicalStructureHandler {
         parentTree.getNums().put(currentPage.getStructParents(), pageParentTreeArray);
     }
 
-    private MarkedContentInfo addToParentTree(String structurePointer) {
-        PDFStructElem parent = (PDFStructElem) structTreeMap.get(structurePointer);
-        if (parent == null) {
-            return ARTIFACT;
-        } else {
-            pageParentTreeArray.add(parent);
-            String type = parent.getStructureType().toString();
-            int mcid = pageParentTreeArray.length() - 1;
-            return new MarkedContentInfo(type, mcid, parent);
-        }
+    private MarkedContentInfo addToParentTree(PDFStructElem structureTreeElement) {
+        PDFStructElem parent = (structureTreeElement instanceof PDFStructElem.Placeholder)
+                ? structureTreeElement.getParentStructElem()
+                : structureTreeElement;
+        pageParentTreeArray.add(parent);
+        String type = parent.getStructureType().toString();
+        int mcid = pageParentTreeArray.length() - 1;
+        return new MarkedContentInfo(type, mcid, structureTreeElement);
     }
 
     /**
      * Adds a content item corresponding to text into the structure tree, if
      * there is a structure element associated to it.
      *
-     * @param structurePointer reference to the parent structure element of the
-     * piece of text
+     * @param structElem the parent structure element of the piece of text
      * @return the necessary information for bracketing the content as a
      * marked-content sequence. If there is no element in the structure tree
      * associated to that content, returns an instance whose
      * {@link MarkedContentInfo#tag} value is <code>null</code>. The content
      * must then be treated as an artifact.
      */
-    MarkedContentInfo addTextContentItem(String structurePointer) {
-        MarkedContentInfo mci = addToParentTree(structurePointer);
-        if (mci != ARTIFACT) {
+    MarkedContentInfo addTextContentItem(PDFStructElem structElem) {
+        if (structElem == null) {
+            return ARTIFACT;
+        } else {
+            MarkedContentInfo mci = addToParentTree(structElem);
             PDFDictionary contentItem = new PDFDictionary();
             contentItem.put("Type", MCR);
             contentItem.put("Pg", this.currentPage);
             contentItem.put("MCID", mci.mcid);
             mci.parent.addKid(contentItem);
+            return mci;
         }
-        return mci;
     }
 
     /**
      * Adds a content item corresponding to an image into the structure tree, if
      * there is a structure element associated to it.
      *
-     * @param structurePointer reference to the parent structure element of the
-     * image
+     * @param structElem the parent structure element of the image
      * @return the necessary information for bracketing the content as a
      * marked-content sequence. If there is no element in the structure tree
      * associated to that image, returns an instance whose
-     * {@link MarkedContentInfo#tag} value is <code>null</code>. The image
-     * must then be treated as an artifact.
+     * {@link MarkedContentInfo#tag} value is <code>null</code>. The image must
+     * then be treated as an artifact.
      */
-    MarkedContentInfo addImageContentItem(String structurePointer) {
-        MarkedContentInfo mci = addToParentTree(structurePointer);
-        if (mci != ARTIFACT) {
+    MarkedContentInfo addImageContentItem(PDFStructElem structElem) {
+        if (structElem == null) {
+            return ARTIFACT;
+        } else {
+            MarkedContentInfo mci = addToParentTree(structElem);
             mci.parent.setMCIDKid(mci.mcid);
             mci.parent.setPage(this.currentPage);
+            return mci;
         }
-        return mci;
     }
 
-    // While the PDF spec allows images to be referred as PDF objects, this
-    // makes the Acrobat Pro checker complain that the image is not accessible.
-    // Its alt-text is still read aloud though. Using marked-content sequences
-    // like for text works.
-//    MarkedContentInfo addImageObject(String parentReference) {
-//        MarkedContentInfo mci = addToParentTree(parentReference);
-//        if (mci != ARTIFACT) {
-//            PDFDictionary contentItem = new PDFDictionary();
-//            contentItem.put("Type", OBJR);
-//            contentItem.put("Pg", this.currentPage);
-//            contentItem.put("Obj", null);
-//            mci.parent.addKid(contentItem);
-//        }
-//        return mci;
-//    }
-
     /**
      * Adds a content item corresponding to the given link into the structure
      * tree.
      *
      * @param link a link
-     * @param structurePointer reference to the corresponding parent structure element
+     * @param structureTreeElement its parent structure element
      */
-    void addLinkContentItem(PDFLink link, String structurePointer) {
+    void addLinkContentItem(PDFLink link, PDFStructElem structureTreeElement) {
         int structParent = getNextParentTreeKey();
         link.setStructParent(structParent);
         PDFDictionary contentItem = new PDFDictionary();
         contentItem.put("Type", OBJR);
         contentItem.put("Pg", this.currentPage);
         contentItem.put("Obj", link);
-        PDFStructElem parent = (PDFStructElem) structTreeMap.get(structurePointer);
-        parentTree.getNums().put(structParent, parent);
-        parent.addKid(contentItem);
-    }
-
-    void addStructurePointer(String ptr, PDFStructElem structElem) {
-        structTreeMap.put(ptr, structElem);
+        parentTree.getNums().put(structParent, structureTreeElement);
+        structureTreeElement.addKid(contentItem);
     }
 
 }
diff --git a/src/java/org/apache/fop/render/pdf/PDFPainter.java b/src/java/org/apache/fop/render/pdf/PDFPainter.java
index 11af216a2..f2fbfd014 100644
--- a/src/java/org/apache/fop/render/pdf/PDFPainter.java
+++ b/src/java/org/apache/fop/render/pdf/PDFPainter.java
@@ -37,6 +37,7 @@ import org.apache.fop.fonts.SingleByteFont;
 import org.apache.fop.fonts.Typeface;
 import org.apache.fop.pdf.PDFDocument;
 import org.apache.fop.pdf.PDFNumber;
+import org.apache.fop.pdf.PDFStructElem;
 import org.apache.fop.pdf.PDFTextUtil;
 import org.apache.fop.pdf.PDFXObject;
 import org.apache.fop.render.RenderingContext;
@@ -133,24 +134,24 @@ public class PDFPainter extends AbstractIFPainter {
         PDFXObject xobject = getPDFDoc().getXObject(uri);
         if (xobject != null) {
             if (accessEnabled) {
-                String ptr = getContext().getStructurePointer();
-                prepareImageMCID(ptr);
+                PDFStructElem structElem = (PDFStructElem) getContext().getStructureTreeElement();
+                prepareImageMCID(structElem);
                 placeImageAccess(rect, xobject);
             } else {
                 placeImage(rect, xobject);
             }
         } else {
             if (accessEnabled) {
-                String ptr = getContext().getStructurePointer();
-                prepareImageMCID(ptr);
+                PDFStructElem structElem = (PDFStructElem) getContext().getStructureTreeElement();
+                prepareImageMCID(structElem);
             }
             drawImageUsingURI(uri, rect);
             flushPDFDoc();
         }
     }
 
-    private void prepareImageMCID(String ptr) {
-        imageMCI = logicalStructureHandler.addImageContentItem(ptr);
+    private void prepareImageMCID(PDFStructElem structElem) {
+        imageMCI = logicalStructureHandler.addImageContentItem(structElem);
     }
 
     /** {@inheritDoc} */
@@ -194,8 +195,8 @@ public class PDFPainter extends AbstractIFPainter {
     /** {@inheritDoc} */
     public void drawImage(Document doc, Rectangle rect) throws IFException {
         if (accessEnabled) {
-            String ptr = getContext().getStructurePointer();
-            prepareImageMCID(ptr);
+            PDFStructElem structElem = (PDFStructElem) getContext().getStructureTreeElement();
+            prepareImageMCID(structElem);
         }
         drawImageUsingDocument(doc, rect);
         flushPDFDoc();
@@ -294,8 +295,8 @@ public class PDFPainter extends AbstractIFPainter {
             String text)
             throws IFException {
         if (accessEnabled) {
-            String ptr = getContext().getStructurePointer();
-            MarkedContentInfo mci = logicalStructureHandler.addTextContentItem(ptr);
+            PDFStructElem structElem = (PDFStructElem) getContext().getStructureTreeElement();
+            MarkedContentInfo mci = logicalStructureHandler.addTextContentItem(structElem);
             if (generator.getTextUtil().isInTextObject()) {
                 generator.separateTextElements(mci.tag, mci.mcid);
             }
diff --git a/src/java/org/apache/fop/render/pdf/PDFStructureTreeBuilder.java b/src/java/org/apache/fop/render/pdf/PDFStructureTreeBuilder.java
index 8ec10b209..3b5b00c33 100644
--- a/src/java/org/apache/fop/render/pdf/PDFStructureTreeBuilder.java
+++ b/src/java/org/apache/fop/render/pdf/PDFStructureTreeBuilder.java
@@ -24,10 +24,10 @@ import java.util.Locale;
 
 import org.xml.sax.Attributes;
 
+import org.apache.fop.accessibility.StructureTreeElement;
 import org.apache.fop.accessibility.StructureTreeEventHandler;
 import org.apache.fop.events.EventBroadcaster;
 import org.apache.fop.fo.extensions.ExtensionElementMapping;
-import org.apache.fop.fo.extensions.InternalElementMapping;
 import org.apache.fop.pdf.PDFFactory;
 import org.apache.fop.pdf.PDFStructElem;
 
@@ -61,33 +61,64 @@ class PDFStructureTreeBuilder implements StructureTreeEventHandler {
     public void endPageSequence() {
     }
 
-    public void startNode(String name, Attributes attributes) {
+    public StructureTreeElement startNode(String name, Attributes attributes) {
         PDFStructElem parent = ancestors.getFirst();
         String role = attributes.getValue("role");
-        PDFStructElem created = pdfFactory.makeStructureElement(
-                FOToPDFRoleMap.mapFormattingObject(name, role, parent,
-                        eventBroadcaster), parent);
-        if (ancestors.size() <= 2) { // TODO remove
-            parent.addKid(created);
-        }
-        String ptr = attributes.getValue(InternalElementMapping.URI, "ptr");
-        if (ptr != null) {
-            logicalStructureHandler.addStructurePointer(ptr, created);
+        PDFStructElem created;
+        created = pdfFactory.makeStructureElement(
+                FOToPDFRoleMap.mapFormattingObject(name, role, parent, eventBroadcaster), parent);
+        parent.addKid(created);
+        ancestors.addFirst(created);
+        return created;
+    }
+
+    public void endNode(String name) {
+        removeFirstAncestor();
+    }
+
+    private void removeFirstAncestor() {
+        ancestors.removeFirst();
+    }
+
+    public StructureTreeElement startImageNode(String name, Attributes attributes) {
+        PDFStructElem parent = ancestors.getFirst();
+        String role = attributes.getValue("role");
+        PDFStructElem created;
+        created = pdfFactory.makeStructureElement(
+                FOToPDFRoleMap.mapFormattingObject(name, role, parent, eventBroadcaster), parent);
+        parent.addKid(created);
+        String altTextNode = attributes.getValue(ExtensionElementMapping.URI, "alt-text");
+        if (altTextNode != null) {
+            created.put("Alt", altTextNode);
+        } else {
+            created.put("Alt", "No alternate text specified");
         }
+        ancestors.addFirst(created);
+        return created;
+    }
+
+    public void endImageNode(String name) {
+        removeFirstAncestor();
+    }
 
-        if (name.equals("external-graphic") || name.equals("instream-foreign-object")) {
-            String altTextNode = attributes.getValue(ExtensionElementMapping.URI, "alt-text");
-            if (altTextNode != null) {
-                created.put("Alt", altTextNode);
-            } else {
-                created.put("Alt", "No alternate text specified");
-            }
+    public StructureTreeElement startReferencedNode(String name, Attributes attributes) {
+        PDFStructElem parent = ancestors.getFirst();
+        String role = attributes.getValue("role");
+        PDFStructElem created;
+        if ("#PCDATA".equals(name)) {
+            created = new PDFStructElem.Placeholder(parent, name);
+        } else {
+            created = pdfFactory.makeStructureElement(
+                    FOToPDFRoleMap.mapFormattingObject(name, role, parent,
+                            eventBroadcaster), parent);
         }
+        parent.addKid(created);
         ancestors.addFirst(created);
+        return created;
     }
 
-    public void endNode(String name) {
-        ancestors.removeFirst();
+    public void endReferencedNode(String name) {
+        removeFirstAncestor();
     }
 
 }
diff --git a/src/java/org/apache/fop/render/rtf/RTFHandler.java b/src/java/org/apache/fop/render/rtf/RTFHandler.java
index 8878b5d24..a3e3db461 100644
--- a/src/java/org/apache/fop/render/rtf/RTFHandler.java
+++ b/src/java/org/apache/fop/render/rtf/RTFHandler.java
@@ -117,13 +117,13 @@ import org.apache.fop.render.rtf.rtflib.rtfdoc.RtfFootnote;
 import org.apache.fop.render.rtf.rtflib.rtfdoc.RtfHyperLink;
 import org.apache.fop.render.rtf.rtflib.rtfdoc.RtfList;
 import org.apache.fop.render.rtf.rtflib.rtfdoc.RtfListItem;
+import org.apache.fop.render.rtf.rtflib.rtfdoc.RtfListItem.RtfListItemLabel;
 import org.apache.fop.render.rtf.rtflib.rtfdoc.RtfPage;
 import org.apache.fop.render.rtf.rtflib.rtfdoc.RtfSection;
 import org.apache.fop.render.rtf.rtflib.rtfdoc.RtfTable;
 import org.apache.fop.render.rtf.rtflib.rtfdoc.RtfTableCell;
 import org.apache.fop.render.rtf.rtflib.rtfdoc.RtfTableRow;
 import org.apache.fop.render.rtf.rtflib.rtfdoc.RtfTextrun;
-import org.apache.fop.render.rtf.rtflib.rtfdoc.RtfListItem.RtfListItemLabel;
 import org.apache.fop.render.rtf.rtflib.tools.BuilderContext;
 import org.apache.fop.render.rtf.rtflib.tools.PercentContext;
 import org.apache.fop.render.rtf.rtflib.tools.TableContext;
@@ -1362,11 +1362,9 @@ public class RTFHandler extends FOEventHandler {
 
     /**
      * @param text FOText object
-     * @param data Array of characters to process.
-     * @param start Offset for characters to process.
-     * @param length Portion of array to process.
+     * @param characters CharSequence of the characters to process.
      */
-    public void text(FOText text, char[] data, int start, int length) {
+    public void text(FOText text, CharSequence characters) {
         if (bDefer) {
             return;
         }
@@ -1381,7 +1379,7 @@ public class RTFHandler extends FOEventHandler {
                 = TextAttributesConverter.convertCharacterAttributes(text);
 
             textrun.pushInlineAttributes(rtfAttr);
-            textrun.addString(new String(data, start, length - start));
+            textrun.addString(characters.toString());
             textrun.popInlineAttributes();
         } catch (IOException ioe) {
             handleIOTrouble(ioe);
@@ -1558,7 +1556,7 @@ public class RTFHandler extends FOEventHandler {
         } else if (foNode instanceof FOText) {
             if (bStart) {
                 FOText text = (FOText) foNode;
-                text(text, text.getCharArray(), 0, text.length());
+                text(text, text.getCharSequence());
             }
         } else if (foNode instanceof Character) {
             if (bStart) {