Added support for the role property on fo:page-sequence, fo:flow and fo:static-content.

This allows to change the mapping of those FOs to PDF structure types when enabling accessibility.

Suggested by Martin Koegler as part of Bugzilla #50852


git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@1342680 13f79535-47bb-0310-9956-ffa450edef68

3 files changed, 69 insertions, 68 deletions

diff --git a/src/java/org/apache/fop/render/pdf/FOToPDFRoleMap.java b/src/java/org/apache/fop/render/pdf/FOToPDFRoleMap.java
index 9b76d0620..0f752e886 100644
--- a/src/java/org/apache/fop/render/pdf/FOToPDFRoleMap.java
+++ b/src/java/org/apache/fop/render/pdf/FOToPDFRoleMap.java
@@ -103,9 +103,9 @@ final class FOToPDFRoleMap {
         addStructureType("Formula");
         addStructureType("Form");
 
-        NON_STRUCT = (PDFName) STANDARD_STRUCTURE_TYPES.get("NonStruct");
+        NON_STRUCT = STANDARD_STRUCTURE_TYPES.get("NonStruct");
         assert NON_STRUCT != null;
-        THEAD = (PDFName) STANDARD_STRUCTURE_TYPES.get("THead");
+        THEAD = STANDARD_STRUCTURE_TYPES.get("THead");
         assert THEAD != null;
 
         // Create the standard mappings
@@ -155,7 +155,7 @@ final class FOToPDFRoleMap {
     }
 
     private static void addMapping(String fo, String structureType) {
-        PDFName type = (PDFName) STANDARD_STRUCTURE_TYPES.get(structureType);
+        PDFName type = STANDARD_STRUCTURE_TYPES.get(structureType);
         assert type != null;
         addMapping(fo, new SimpleMapper(type));
     }
@@ -168,21 +168,6 @@ final class FOToPDFRoleMap {
     /**
      * Maps a Formatting Object to a PDFName representing the associated structure type.
      * @param fo the formatting object's local name
-     * @param parent the parent of the structure element to be mapped
-     * @return the structure type or null if no match could be found
-     */
-    public static PDFName mapFormattingObject(String fo, PDFObject parent) {
-        Mapper mapper = (Mapper) DEFAULT_MAPPINGS.get(fo);
-        if (mapper != null) {
-            return mapper.getStructureType(parent);
-        } else {
-            return NON_STRUCT;
-        }
-    }
-
-    /**
-     * Maps a Formatting Object to a PDFName representing the associated structure type.
-     * @param fo the formatting object's local name
      * @param role the value of the formatting object's role property
      * @param parent the parent of the structure element to be mapped
      * @param eventBroadcaster the event broadcaster
@@ -192,11 +177,11 @@ final class FOToPDFRoleMap {
             PDFObject parent, EventBroadcaster eventBroadcaster) {
         PDFName type = null;
         if (role == null) {
-            type = mapFormattingObject(fo, parent);
+            type = getDefaultMappingFor(fo, parent);
         } else {
-            type = (PDFName) STANDARD_STRUCTURE_TYPES.get(role);
+            type = STANDARD_STRUCTURE_TYPES.get(role);
             if (type == null) {
-                type = mapFormattingObject(fo, parent);
+                type = getDefaultMappingFor(fo, parent);
                 PDFEventProducer.Provider.get(eventBroadcaster).nonStandardStructureType(fo,
                         fo, role, type.toString().substring(1));
             }
@@ -205,6 +190,21 @@ final class FOToPDFRoleMap {
         return type;
     }
 
+    /**
+     * Maps a Formatting Object to a PDFName representing the associated structure type.
+     * @param fo the formatting object's local name
+     * @param parent the parent of the structure element to be mapped
+     * @return the structure type or NonStruct if no match could be found
+     */
+    private static PDFName getDefaultMappingFor(String fo, PDFObject parent) {
+        Mapper mapper = DEFAULT_MAPPINGS.get(fo);
+        if (mapper != null) {
+            return mapper.getStructureType(parent);
+        } else {
+            return NON_STRUCT;
+        }
+    }
+
     private interface Mapper {
         PDFName getStructureType(PDFObject parent);
     }
@@ -226,14 +226,13 @@ final class FOToPDFRoleMap {
     private static class TableCellMapper implements Mapper {
 
         public PDFName getStructureType(PDFObject parent) {
-            PDFStructElem grandParent = (PDFStructElem)
-                ((PDFStructElem) parent).getParentStructElem();
+            PDFStructElem grandParent = ((PDFStructElem) parent).getParentStructElem();
             //TODO What to do with cells from table-footer? Currently they are mapped on TD.
             PDFName type;
             if (THEAD.equals(grandParent.getStructureType())) {
-               type = (PDFName) STANDARD_STRUCTURE_TYPES.get("TH");
+               type = STANDARD_STRUCTURE_TYPES.get("TH");
             } else {
-                type = (PDFName) STANDARD_STRUCTURE_TYPES.get("TD");
+                type = STANDARD_STRUCTURE_TYPES.get("TD");
             }
             assert type != null;
             return type;
diff --git a/src/java/org/apache/fop/render/pdf/PDFLogicalStructureHandler.java b/src/java/org/apache/fop/render/pdf/PDFLogicalStructureHandler.java
index 1c9f9b49d..6559e8d56 100644
--- a/src/java/org/apache/fop/render/pdf/PDFLogicalStructureHandler.java
+++ b/src/java/org/apache/fop/render/pdf/PDFLogicalStructureHandler.java
@@ -19,8 +19,6 @@
 
 package org.apache.fop.render.pdf;
 
-import java.util.Locale;
-
 import org.apache.fop.pdf.PDFArray;
 import org.apache.fop.pdf.PDFDictionary;
 import org.apache.fop.pdf.PDFDocument;
@@ -29,7 +27,6 @@ import org.apache.fop.pdf.PDFName;
 import org.apache.fop.pdf.PDFPage;
 import org.apache.fop.pdf.PDFParentTree;
 import org.apache.fop.pdf.PDFStructElem;
-import org.apache.fop.pdf.PDFStructTreeRoot;
 
 
 /**
@@ -59,8 +56,6 @@ class PDFLogicalStructureHandler {
      */
     private PDFArray pageParentTreeArray;
 
-    private PDFStructElem rootStructureElement;
-
     /**
      * Class providing the necessary information for bracketing content
      * associated to a structure element as a marked-content sequence.
@@ -95,22 +90,10 @@ class PDFLogicalStructureHandler {
      */
     PDFLogicalStructureHandler(PDFDocument pdfDoc) {
         this.pdfDoc = pdfDoc;
-        PDFStructTreeRoot structTreeRoot = pdfDoc.makeStructTreeRoot(parentTree);
-        rootStructureElement = pdfDoc.makeStructureElement(
-                FOToPDFRoleMap.mapFormattingObject("root", structTreeRoot), structTreeRoot);
-        structTreeRoot.addKid(rootStructureElement);
     }
 
-
-    PDFStructElem createPageSequence(Locale language) {
-        PDFStructElem structElemPart = pdfDoc.makeStructureElement(
-                FOToPDFRoleMap.mapFormattingObject("page-sequence", rootStructureElement),
-                rootStructureElement);
-        rootStructureElement.addKid(structElemPart);
-        if (language != null) {
-            structElemPart.setLanguage(language);
-        }
-        return structElemPart;
+    PDFParentTree getParentTree() {
+        return parentTree;
     }
 
     private int getNextParentTreeKey() {
diff --git a/src/java/org/apache/fop/render/pdf/PDFStructureTreeBuilder.java b/src/java/org/apache/fop/render/pdf/PDFStructureTreeBuilder.java
index 2a2a4a392..3839d47bc 100644
--- a/src/java/org/apache/fop/render/pdf/PDFStructureTreeBuilder.java
+++ b/src/java/org/apache/fop/render/pdf/PDFStructureTreeBuilder.java
@@ -29,7 +29,11 @@ import org.apache.fop.accessibility.StructureTreeEventHandler;
 import org.apache.fop.events.EventBroadcaster;
 import org.apache.fop.fo.extensions.ExtensionElementMapping;
 import org.apache.fop.pdf.PDFFactory;
+import org.apache.fop.pdf.PDFName;
+import org.apache.fop.pdf.PDFObject;
+import org.apache.fop.pdf.PDFParentTree;
 import org.apache.fop.pdf.PDFStructElem;
+import org.apache.fop.pdf.PDFStructTreeRoot;
 
 class PDFStructureTreeBuilder implements StructureTreeEventHandler {
 
@@ -41,21 +45,42 @@ class PDFStructureTreeBuilder implements StructureTreeEventHandler {
 
     private LinkedList<PDFStructElem> ancestors = new LinkedList<PDFStructElem>();
 
+    private PDFStructElem rootStructureElement;
+
     void setPdfFactory(PDFFactory pdfFactory) {
         this.pdfFactory = pdfFactory;
     }
 
     void setLogicalStructureHandler(PDFLogicalStructureHandler logicalStructureHandler) {
         this.logicalStructureHandler = logicalStructureHandler;
+        createRootStructureElement();
+    }
+
+    private void createRootStructureElement() {
+        assert rootStructureElement == null;
+        PDFParentTree parentTree = logicalStructureHandler.getParentTree();
+        PDFStructTreeRoot structTreeRoot = pdfFactory.getDocument().makeStructTreeRoot(parentTree);
+        rootStructureElement = createStructureElement("root", structTreeRoot, null);
+        structTreeRoot.addKid(rootStructureElement);
     }
 
     void setEventBroadcaster(EventBroadcaster eventBroadcaster) {
         this.eventBroadcaster = eventBroadcaster;
     }
 
-    public void startPageSequence(Locale locale) {
+    public void startPageSequence(Locale language, String role) {
         ancestors = new LinkedList<PDFStructElem>();
-        ancestors.add(logicalStructureHandler.createPageSequence(locale));
+        PDFStructElem structElem = createStructureElement("page-sequence", rootStructureElement, role);
+        if (language != null) {
+            structElem.setLanguage(language);
+        }
+        rootStructureElement.addKid(structElem);
+        ancestors.add(structElem);
+    }
+
+    private PDFStructElem createStructureElement(String name, PDFObject parent, String role) {
+        PDFName structureType = FOToPDFRoleMap.mapFormattingObject(name, role, parent, eventBroadcaster);
+        return pdfFactory.getDocument().makeStructureElement(structureType, parent);
     }
 
     public void endPageSequence() {
@@ -64,12 +89,10 @@ class PDFStructureTreeBuilder implements StructureTreeEventHandler {
     public StructureTreeElement startNode(String name, Attributes attributes) {
         PDFStructElem parent = ancestors.getFirst();
         String role = attributes.getValue("role");
-        PDFStructElem created;
-        created = pdfFactory.getDocument().makeStructureElement(
-                FOToPDFRoleMap.mapFormattingObject(name, role, parent, eventBroadcaster), parent);
-        parent.addKid(created);
-        ancestors.addFirst(created);
-        return created;
+        PDFStructElem structElem = createStructureElement(name, parent, role);
+        parent.addKid(structElem);
+        ancestors.addFirst(structElem);
+        return structElem;
     }
 
     public void endNode(String name) {
@@ -83,34 +106,30 @@ class PDFStructureTreeBuilder implements StructureTreeEventHandler {
     public StructureTreeElement startImageNode(String name, Attributes attributes) {
         PDFStructElem parent = ancestors.getFirst();
         String role = attributes.getValue("role");
-        PDFStructElem created;
-        created = pdfFactory.getDocument().makeStructureElement(
-                FOToPDFRoleMap.mapFormattingObject(name, role, parent, eventBroadcaster), parent);
-        parent.addKid(created);
+        PDFStructElem structElem = createStructureElement(name, parent, role);
+        parent.addKid(structElem);
         String altTextNode = attributes.getValue(ExtensionElementMapping.URI, "alt-text");
         if (altTextNode != null) {
-            created.put("Alt", altTextNode);
+            structElem.put("Alt", altTextNode);
         } else {
-            created.put("Alt", "No alternate text specified");
+            structElem.put("Alt", "No alternate text specified");
         }
-        ancestors.addFirst(created);
-        return created;
+        ancestors.addFirst(structElem);
+        return structElem;
     }
 
     public StructureTreeElement startReferencedNode(String name, Attributes attributes) {
         PDFStructElem parent = ancestors.getFirst();
         String role = attributes.getValue("role");
-        PDFStructElem created;
+        PDFStructElem structElem;
         if ("#PCDATA".equals(name)) {
-            created = new PDFStructElem.Placeholder(parent, name);
+            structElem = new PDFStructElem.Placeholder(parent, name);
         } else {
-            created = pdfFactory.getDocument().makeStructureElement(
-                    FOToPDFRoleMap.mapFormattingObject(name, role, parent,
-                            eventBroadcaster), parent);
+            structElem = createStructureElement(name, parent, role);
         }
-        parent.addKid(created);
-        ancestors.addFirst(created);
-        return created;
+        parent.addKid(structElem);
+        ancestors.addFirst(structElem);
+        return structElem;
     }
 
 }