Bugzilla #53596: When PDF accessibility is enabled, the structure tree must contain information about the number of columns or rows spanned by a table cell.

git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@1365162 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/fop/accessibility/fo/StructureTreeEventTrigger.java

@@ -221,14 +221,17 @@ class StructureTreeEventTrigger extends FOEventHandler {
     @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));
-        }
+        addSpanAttribute(attributes, "number-columns-spanned", tc.getNumberColumnsSpanned());
+        addSpanAttribute(attributes, "number-rows-spanned", tc.getNumberRowsSpanned());
         startElement(tc, attributes);
     }
 
+    private void addSpanAttribute(AttributesImpl attributes, String attributeName, int span) {
+        if (span > 1) {
+            addNoNamespaceAttribute(attributes, attributeName, Integer.toString(span));
+        }
+    }
+
     @Override
     public void endCell(TableCell tc) {
         endElement(tc);

src/java/org/apache/fop/pdf/PDFArray.java

@@ -99,6 +99,15 @@ public class PDFArray extends PDFObject {
         this(null, elements);
     }
 
+    /**
+     * Creates an array object made of the given elements.
+     *
+     * @param elements the array content
+     */
+    public PDFArray(List<?> elements) {
+        this(null, elements);
+    }
+
     /**
      * Create the array object
      * @param parent the array's parent if any

src/java/org/apache/fop/pdf/PDFStructElem.java

@@ -33,6 +33,8 @@ import org.apache.fop.util.LanguageTags;
  */
 public class PDFStructElem extends PDFDictionary implements StructureTreeElement, CompressedObject {
 
+    private static final PDFName TABLE = new PDFName("Table");
+
     private PDFStructElem parentElement;
 
     /**
@@ -40,6 +42,8 @@ public class PDFStructElem extends PDFDictionary implements StructureTreeElement
      */
     protected List<PDFObject> kids;
 
+    private List<PDFDictionary> attributes;
+
     /**
      * Creates a new structure element.
      *
@@ -143,9 +147,21 @@ public class PDFStructElem extends PDFDictionary implements StructureTreeElement
     @Override
     protected void writeDictionary(OutputStream out, StringBuilder textBuffer) throws IOException {
         attachKids();
+        attachAttributes();
         super.writeDictionary(out, textBuffer);
     }
 
+    private void attachAttributes() {
+        if (attributes != null) {
+            if (attributes.size() == 1) {
+                put("A", attributes.get(0));
+            } else {
+                PDFArray array = new PDFArray(attributes);
+                put("A", array);
+            }
+        }
+    }
+
     /**
      * Attaches all valid kids to the kids array.
      *
@@ -175,6 +191,24 @@ public class PDFStructElem extends PDFDictionary implements StructureTreeElement
         return kidsAttached;
     }
 
+    public void setTableAttributeColSpan(int colSpan) {
+        setTableAttributeRowColumnSpan("ColSpan", colSpan);
+    }
+
+    public void setTableAttributeRowSpan(int rowSpan) {
+        setTableAttributeRowColumnSpan("RowSpan", rowSpan);
+    }
+
+    private void setTableAttributeRowColumnSpan(String typeSpan, int span) {
+        PDFDictionary attribute = new PDFDictionary();
+        attribute.put("O", TABLE);
+        attribute.put(typeSpan, span);
+        if (attributes == null) {
+            attributes = new ArrayList<PDFDictionary>(2);
+        }
+        attributes.add(attribute);
+    }
+
     /**
      * Class representing a placeholder for a PDF Structure Element.
      */

src/java/org/apache/fop/render/pdf/PDFStructureTreeBuilder.java

@@ -90,11 +90,23 @@ class PDFStructureTreeBuilder implements StructureTreeEventHandler {
         PDFStructElem parent = ancestors.getFirst();
         String role = attributes.getValue("role");
         PDFStructElem structElem = createStructureElement(name, parent, role);
+        setSpanAttributes(structElem, attributes);
         parent.addKid(structElem);
         ancestors.addFirst(structElem);
         return structElem;
     }
 
+    private void setSpanAttributes(PDFStructElem structElem, Attributes attributes) {
+        String columnSpan = attributes.getValue("number-columns-spanned");
+        if (columnSpan != null) {
+            structElem.setTableAttributeColSpan(Integer.parseInt(columnSpan));
+        }
+        String rowSpan = attributes.getValue("number-rows-spanned");
+        if (rowSpan != null) {
+            structElem.setTableAttributeRowSpan(Integer.parseInt(rowSpan));
+        }
+    }
+
     public void endNode(String name) {
         removeFirstAncestor();
     }

status.xml

@@ -62,6 +62,10 @@
       documents. Example: the fix of marks layering will be such a case when it's done.
     -->
     <release version="FOP Trunk" date="TBD">
+      <action context="Renderers" dev="VH" type="add" fixes-bug="53596">
+        When PDF accessibility is enabled, the structure tree must contain information about the 
+        number of columns or rows spanned by a table cell.
+      </action>
       <action context="Renderers" dev="MH" type="add" fixes-bug="53563" importance="low">
         Removed a method call to the java.awt.GraphicsEnvironment.getLocalGraphicsEnvironment().getDefaultScreenDevice()
         that could (in a headless environment) throw a java.awt.HeadlessException

test/pdf/accessibility/table_row-col-span.fo

@@ -0,0 +1,147 @@
+<?xml version="1.0" encoding="utf-8"?>
+<fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format">
+  <fo:layout-master-set>
+    <fo:simple-page-master master-name="page" page-height="320pt" page-width="420pt" margin="10pt">
+      <fo:region-body display-align="center"/>
+    </fo:simple-page-master>
+  </fo:layout-master-set>
+  <fo:page-sequence master-reference="page">
+    <fo:flow flow-name="xsl-region-body">
+      <fo:table table-layout="fixed" width="100%" border-collapse="separate" 
+        border-separation="4pt">
+        <fo:table-body>
+          <fo:table-row>
+            <fo:table-cell number-columns-spanned="2" background-color="orange" padding-left="1pt">
+              <fo:block>Cells 1.1 and 1.2.</fo:block>
+            </fo:table-cell>
+            <fo:table-cell>
+              <fo:block>Cell 1.3.</fo:block>
+            </fo:table-cell>
+            <fo:table-cell>
+              <fo:block>Cell 1.4.</fo:block>
+            </fo:table-cell>
+          </fo:table-row>
+          <fo:table-row>
+            <fo:table-cell>
+              <fo:block>Cell 2.1.</fo:block>
+            </fo:table-cell>
+            <fo:table-cell number-columns-spanned="2" background-color="orange" padding-left="1pt">
+              <fo:block>Cells 2.2 and 2.3.</fo:block>
+            </fo:table-cell>
+            <fo:table-cell>
+              <fo:block>Cell 2.4.</fo:block>
+            </fo:table-cell>
+          </fo:table-row>
+          <fo:table-row>
+            <fo:table-cell>
+              <fo:block>Cell 3.1.</fo:block>
+            </fo:table-cell>
+            <fo:table-cell>
+              <fo:block>Cell 3.2.</fo:block>
+            </fo:table-cell>
+            <fo:table-cell number-columns-spanned="2" background-color="orange" padding-left="1pt">
+              <fo:block>Cells 3.3 and 3.4.</fo:block>
+            </fo:table-cell>
+          </fo:table-row>
+          <fo:table-row>
+            <fo:table-cell number-columns-spanned="3" background-color="orange" padding-left="1pt">
+              <fo:block>Cells 4.1, 4.2 and 4.3.</fo:block>
+            </fo:table-cell>
+            <fo:table-cell>
+              <fo:block>Cell 4.4.</fo:block>
+            </fo:table-cell>
+          </fo:table-row>
+          <fo:table-row>
+            <fo:table-cell number-columns-spanned="4" background-color="orange" padding-left="1pt">
+              <fo:block>Cells 5.1, 5.2, 5.3 and 5.4.</fo:block>
+            </fo:table-cell>
+          </fo:table-row>
+        </fo:table-body>
+      </fo:table>
+
+      <fo:table table-layout="fixed" width="100%" space-before="40pt" border-collapse="separate" 
+        border-separation="4pt">
+        <fo:table-body>
+          <fo:table-row>
+            <fo:table-cell number-rows-spanned="2" background-color="orange" padding-left="1pt">
+              <fo:block>Cells 1.1</fo:block>
+              <fo:block>and 2.1.</fo:block>
+            </fo:table-cell>
+            <fo:table-cell>
+              <fo:block>Cell 1.2.</fo:block>
+            </fo:table-cell>
+            <fo:table-cell>
+              <fo:block>Cell 1.3.</fo:block>
+            </fo:table-cell>
+            <fo:table-cell number-rows-spanned="4" background-color="orange" padding-left="1pt">
+              <fo:block>Cells 1.4,</fo:block>
+              <fo:block>2.4,</fo:block>
+              <fo:block>3.4</fo:block>
+              <fo:block>and 4.4.</fo:block>
+            </fo:table-cell>
+          </fo:table-row>
+          <fo:table-row>
+            <fo:table-cell number-rows-spanned="2" background-color="orange" padding-left="1pt">
+              <fo:block>Cells 2.2</fo:block>
+              <fo:block>and 3.2.</fo:block>
+            </fo:table-cell>
+            <fo:table-cell number-rows-spanned="3" background-color="orange" padding-left="1pt">
+              <fo:block>Cells 2.3,</fo:block>
+              <fo:block>3.3</fo:block>
+              <fo:block>and 4.3.</fo:block>
+            </fo:table-cell>
+          </fo:table-row>
+          <fo:table-row>
+            <fo:table-cell>
+              <fo:block>Cell 3.1.</fo:block>
+            </fo:table-cell>
+          </fo:table-row>
+          <fo:table-row>
+            <fo:table-cell>
+              <fo:block>Cell 4.1.</fo:block>
+            </fo:table-cell>
+            <fo:table-cell>
+              <fo:block>Cell 4.2.</fo:block>
+            </fo:table-cell>
+          </fo:table-row>
+        </fo:table-body>
+      </fo:table>
+
+      <fo:table table-layout="fixed" width="100%" space-before="40pt" border-collapse="separate" 
+        border-separation="4pt">
+        <fo:table-body>
+          <fo:table-row>
+            <fo:table-cell number-rows-spanned="2" number-columns-spanned="3" 
+              background-color="orange" padding-left="1pt">
+              <fo:block>Cells 1.1, 1.2, 1.3</fo:block>
+              <fo:block>and 2.1, 2.2, 2.3.</fo:block>
+            </fo:table-cell>
+            <fo:table-cell>
+              <fo:block>Cell 1.4.</fo:block>
+            </fo:table-cell>
+          </fo:table-row>
+          <fo:table-row>
+            <fo:table-cell>
+              <fo:block>Cell 2.4.</fo:block>
+            </fo:table-cell>
+          </fo:table-row>
+          <fo:table-row>
+            <fo:table-cell>
+              <fo:block>Cell 3.1.</fo:block>
+            </fo:table-cell>
+            <fo:table-cell>
+              <fo:block>Cell 3.2.</fo:block>
+            </fo:table-cell>
+            <fo:table-cell>
+              <fo:block>Cell 3.3.</fo:block>
+            </fo:table-cell>
+            <fo:table-cell>
+              <fo:block>Cell 3.4.</fo:block>
+            </fo:table-cell>
+          </fo:table-row>
+        </fo:table-body>
+      </fo:table>
+
+    </fo:flow>
+  </fo:page-sequence>
+</fo:root>