FOP-3224: Add alt text to link dictionary

apache · Dec 4, 2024 · fd08436 · fd08436
1 parent 2f18585
commit fd08436
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Showing 14 changed files with 112 additions and 26 deletions.
diff --git a/fop-core/src/main/java/org/apache/fop/area/Trait.java b/fop-core/src/main/java/org/apache/fop/area/Trait.java
@@ -420,16 +420,18 @@ public static class ExternalLink implements Serializable {
 
         private String destination;
         private boolean newWindow;
+        private String altText;
 
         /**
          * Constructs an ExternalLink object with the given destination
          *
          * @param destination   target of the link
          * @param newWindow     true if the target should be opened in a new window
          */
-        public ExternalLink(String destination, boolean newWindow) {
+        public ExternalLink(String destination, boolean newWindow, String altText) {
             this.destination = destination;
             this.newWindow = newWindow;
+            this.altText = altText;
         }
 
         /**
@@ -452,7 +454,7 @@ protected static ExternalLink makeFromTraitValue(String traitValue) {
                             "Malformed trait value for Trait.ExternalLink: " + traitValue);
                 }
             }
-            return new ExternalLink(dest, newWindow);
+            return new ExternalLink(dest, newWindow, null);
         }
 
         /**
@@ -483,6 +485,10 @@ public String toString() {
             sb.append(",dest=").append(this.destination);
             return sb.toString();
         }
+
+        public String getAltText() {
+            return altText;
+        }
     }
 
     /**

diff --git a/fop-core/src/main/java/org/apache/fop/layoutmgr/inline/BasicLinkLayoutManager.java b/fop-core/src/main/java/org/apache/fop/layoutmgr/inline/BasicLinkLayoutManager.java
@@ -81,7 +81,7 @@ private void setupBasicLinkArea(InlineArea area) {
             boolean newWindow = (fobj.getShowDestination() == Constants.EN_NEW);
             if (url.length() > 0) {
                 area.addTrait(Trait.EXTERNAL_LINK,
-                        new Trait.ExternalLink(url, newWindow));
+                        new Trait.ExternalLink(url, newWindow, fobj.getAltText()));
             }
         }
     }

diff --git a/fop-core/src/main/java/org/apache/fop/pdf/PDFFactory.java b/fop-core/src/main/java/org/apache/fop/pdf/PDFFactory.java
@@ -556,7 +556,7 @@ public PDFLink makeLink(Rectangle2D rect, String destination,
         PDFLink link = new PDFLink(rect);
 
         if (linkType == PDFLink.EXTERNAL) {
-            link.setAction(getExternalAction(destination, false));
+            link.setAction(getExternalAction(destination, false, null));
         } else {
             // linkType is internal
             String goToReference = getGoToReference(destination, yoffset);
@@ -583,7 +583,7 @@ public PDFLink makeLink(Rectangle2D rect, String destination,
      *                  displayed in a new window
      * @return the PDFAction thus created or found
      */
-    public PDFAction getExternalAction(String target, boolean newWindow) {
+    public PDFAction getExternalAction(String target, boolean newWindow, String altText) {
         URI uri = getTargetUri(target);
         if (uri != null) {
             String scheme = uri.getScheme();
@@ -595,7 +595,7 @@ public PDFAction getExternalAction(String target, boolean newWindow) {
                 scheme = "file";
             }
             if (scheme == null) {
-                return new PDFUri(uri.toASCIIString());
+                return new PDFUri(uri.toASCIIString(), altText);
             } else if (scheme.equalsIgnoreCase("embedded-file")) {
                 return getActionForEmbeddedFile(filename, newWindow);
             } else if (scheme.equalsIgnoreCase("file")) {
@@ -619,16 +619,16 @@ public PDFAction getExternalAction(String target, boolean newWindow) {
                     return getGoToPDFAction(filename, dest, page, newWindow);
                 } else {
                     if (uri.getQuery() != null || uri.getFragment() != null) {
-                        return new PDFUri(uri.toASCIIString());
+                        return new PDFUri(uri.toASCIIString(), altText);
                     } else {
                         return getLaunchAction(filename, newWindow);
                     }
                 }
             } else {
-                return new PDFUri(uri.toASCIIString());
+                return new PDFUri(uri.toASCIIString(), altText);
             }
         }
-        return new PDFUri(target);
+        return new PDFUri(target, altText);
     }
 
     private URI getTargetUri(String target) {

diff --git a/fop-core/src/main/java/org/apache/fop/pdf/PDFLink.java b/fop-core/src/main/java/org/apache/fop/pdf/PDFLink.java
@@ -93,15 +93,21 @@ public String toPDFString() {
             f |= 1 << (5 - 1); //NoRotate, bit 5
             fFlag = "/F " + f;
         }
-        String s = "<< /Type /Annot\n" + "/Subtype /Link\n" + "/Rect [ "
+        String dict = "<< /Type /Annot\n" + "/Subtype /Link\n" + "/Rect [ "
                    + (ulx) + " " + (uly) + " "
                    + (brx) + " " + (bry) + " ]\n" + "/C [ "
                    + this.color + " ]\n" + "/Border [ 0 0 0 ]\n" + "/A "
                    + this.action.getAction() + "\n" + "/H /I\n"
                    + (this.structParent != null
-                           ? "/StructParent " + this.structParent.toString() + "\n" : "")
-                   + fFlag + "\n>>";
-        return s;
+                           ? "/StructParent " + this.structParent.toString() + "\n" : "");
+        if (action instanceof PDFUri) {
+            String altText = ((PDFUri) action).getAltText();
+            if (altText != null && !altText.isEmpty()) {
+                dict += "/Contents " + PDFText.escapeText(altText) + "\n";
+            }
+        }
+        dict += fFlag + "\n>>";
+        return dict;
     }
 
     /*

diff --git a/fop-core/src/main/java/org/apache/fop/pdf/PDFUri.java b/fop-core/src/main/java/org/apache/fop/pdf/PDFUri.java
@@ -25,14 +25,16 @@
 public class PDFUri extends PDFAction {
 
     private String uri;
+    private String altText;
 
     /**
      * create a Uri instance.
      *
      * @param uri the uri to which the link should point
      */
-    public PDFUri(String uri) {
+    public PDFUri(String uri, String altText) {
         this.uri = uri;
+        this.altText = altText;
     }
 
     /**
@@ -57,4 +59,8 @@ public String toPDFString() {
         //TODO Convert this class into a dictionary
         return getDictString();
     }
+
+    public String getAltText() {
+        return altText;
+    }
 }
diff --git a/fop-core/src/main/java/org/apache/fop/render/intermediate/IFRenderer.java b/fop-core/src/main/java/org/apache/fop/render/intermediate/IFRenderer.java
@@ -965,7 +965,7 @@ public void renderInlineParent(InlineParent ip) {
                 String extDest = extLink.getDestination();
                 if (extDest != null && extDest.length() > 0) {
                     linkTraitFound = true;
-                    action = new URIAction(extDest, extLink.newWindow());
+                    action = new URIAction(extDest, extLink.newWindow(), extLink.getAltText());
                     action = actionSet.put(action);
                 }
             }

diff --git a/...rc/main/java/org/apache/fop/render/intermediate/extensions/DocumentNavigationHandler.java b/...rc/main/java/org/apache/fop/render/intermediate/extensions/DocumentNavigationHandler.java
@@ -165,8 +165,9 @@ public void startElement(String uri, String localName, String qName, Attributes
                 String id = attributes.getValue("id");
                 String gotoURI = attributes.getValue("uri");
                 String showDestination = attributes.getValue("show-destination");
+                String altText = attributes.getValue("alt-text");
                 boolean newWindow = "new".equals(showDestination);
-                URIAction action = new URIAction(gotoURI, newWindow);
+                URIAction action = new URIAction(gotoURI, newWindow, altText);
                 if (id != null) {
                     action.setID(id);
                 }

diff --git a/fop-core/src/main/java/org/apache/fop/render/intermediate/extensions/URIAction.java b/fop-core/src/main/java/org/apache/fop/render/intermediate/extensions/URIAction.java
@@ -33,18 +33,20 @@ public class URIAction extends AbstractAction implements DocumentNavigationExten
 
     private String uri;
     private boolean newWindow;
+    private String altText;
 
     /**
      * Creates a new instance.
      * @param uri the target URI
      * @param newWindow true if the link should be opened in a new window
      */
-    public URIAction(String uri, boolean newWindow) {
+    public URIAction(String uri, boolean newWindow, String altText) {
         if (uri == null) {
             throw new NullPointerException("uri must not be null");
         }
         this.uri = uri;
         this.newWindow = newWindow;
+        this.altText = altText;
         setID(getIDPrefix() + (uri + newWindow).hashCode());
     }
 
@@ -97,6 +99,9 @@ public void toSAX(ContentHandler handler) throws SAXException {
             atts.addAttribute("", "id", "id", XMLUtil.CDATA, getID());
         }
         atts.addAttribute("", "uri", "uri", XMLUtil.CDATA, getURI());
+        if (altText != null && !altText.isEmpty()) {
+            atts.addAttribute("", "alt-text", "alt-text", XMLUtil.CDATA, altText);
+        }
         if (isNewWindow()) {
             atts.addAttribute("", "show-destination", "show-destination", XMLUtil.CDATA, "new");
         }
@@ -106,4 +111,7 @@ public void toSAX(ContentHandler handler) throws SAXException {
                 GOTO_URI.getLocalName(), GOTO_URI.getQName());
     }
 
+    public String getAltText() {
+        return altText;
+    }
 }
diff --git a/fop-core/src/main/java/org/apache/fop/render/pdf/PDFDocumentNavigationHandler.java b/fop-core/src/main/java/org/apache/fop/render/pdf/PDFDocumentNavigationHandler.java
@@ -171,7 +171,7 @@ private PDFAction getAction(AbstractAction action) throws IFException {
             assert u.isComplete();
             String uri = u.getURI();
             PDFFactory factory = getPDFDoc().getFactory();
-            pdfAction = factory.getExternalAction(uri, u.isNewWindow());
+            pdfAction = factory.getExternalAction(uri, u.isNewWindow(), u.getAltText());
             if (!pdfAction.hasObjectNumber()) {
                 //Some PDF actions are pooled
                 getPDFDoc().registerObject(pdfAction);

diff --git a/fop-core/src/test/java/org/apache/fop/pdf/PDFAttachmentTestCase.java b/fop-core/src/test/java/org/apache/fop/pdf/PDFAttachmentTestCase.java
@@ -53,7 +53,7 @@ public void testAddEmbeddedFile() throws IFException {
         docHandler.startPage(0, "", "", new Dimension());
         docHandler.handleExtensionObject(new PDFEmbeddedFileAttachment("filename", "src", "desc"));
         docHandler.getDocumentNavigationHandler().renderLink(new Link(
-                new URIAction("embedded-file:filename", false), new Rectangle()));
+                new URIAction("embedded-file:filename", false, null), new Rectangle()));
         docHandler.endDocument();
         Assert.assertTrue(out.toString().contains(
                 "<<\n  /Type /Filespec\n  /F (filename)\n  /UF (filename)\n  /AFRelationship /Data"));
@@ -76,7 +76,7 @@ public void testAddEmbeddedFileGermanUmlaut() throws IFException {
                 "src", "desc");
         docHandler.handleExtensionObject(fileAtt);
         docHandler.getDocumentNavigationHandler().renderLink(new Link(
-                new URIAction("embedded-file:" + unicodeFilename, false), new Rectangle()));
+                new URIAction("embedded-file:" + unicodeFilename, false, null), new Rectangle()));
         docHandler.endDocument();
         Assert.assertTrue(out.toString().contains(
                 "<<\n  /Type /Filespec\n  /F (" + fileAtt.getFilename() + ")\n  /UF "
@@ -99,7 +99,7 @@ public void testAddEmbeddedFileParenthesis() throws IFException {
                 "src", "desc");
         docHandler.handleExtensionObject(fileAtt);
         docHandler.getDocumentNavigationHandler().renderLink(new Link(
-                new URIAction("embedded-file:" + unicodeFilename, false), new Rectangle()));
+                new URIAction("embedded-file:" + unicodeFilename, false, null), new Rectangle()));
         docHandler.endDocument();
         Assert.assertTrue(out.toString().contains(
                 "<<\n  /Type /Filespec\n  /F (t\\(st)\n  /UF (t\\(st)\n  /AFRelationship /Data"));

diff --git a/fop-core/src/test/java/org/apache/fop/pdf/PDFFactoryTestCase.java b/fop-core/src/test/java/org/apache/fop/pdf/PDFFactoryTestCase.java
@@ -259,7 +259,7 @@ public void testGetExternalAction() {
         PDFFactory pdfFactory = new PDFFactory(doc);
         String target = "embedded-file:" + unicodeFilename;
         PDFJavaScriptLaunchAction pdfAction = (PDFJavaScriptLaunchAction)
-                pdfFactory.getExternalAction(target, false);
+                pdfFactory.getExternalAction(target, false, null);
 
         String expectedString = "<<\n/S /JavaScript\n/JS (this.exportDataObject\\({cName:\""
                 + fileSpec.getFilename() + "\", nLaunch:2}\\);)\n>>";
@@ -281,4 +281,16 @@ public void testMakeLink() {
 
         assertEquals(expectedString, link.toPDFString());
     }
+
+    @Test
+    public void testLinkAltText() throws IOException {
+        PDFDocument doc = new PDFDocument("");
+        PDFFactory pdfFactory = new PDFFactory(doc);
+        PDFAction action = pdfFactory.getExternalAction("a", false, "b");
+        PDFLink link = pdfFactory.makeLink(new Rectangle(), "a", 0, 0);
+        link.setAction(action);
+        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        link.output(bos);
+        assertTrue(bos.toString().contains("/Contents (b)"));
+    }
 }
diff --git a/fop-core/src/test/java/org/apache/fop/pdf/PDFLinkTestCase.java b/fop-core/src/test/java/org/apache/fop/pdf/PDFLinkTestCase.java
@@ -413,7 +413,7 @@ public void testLinks() throws IFException {
         docHandler.startDocument();
         docHandler.startPage(0, "", "", new Dimension());
         docHandler.getDocumentNavigationHandler().renderLink(new Link(
-                new URIAction(target, false), new Rectangle()));
+                new URIAction(target, false, null), new Rectangle()));
         docHandler.endDocument();
 
         // Normalize spaces between word for easier testing

diff --git a/fop-core/src/test/java/org/apache/fop/render/intermediate/URIActionTestCase.java b/fop-core/src/test/java/org/apache/fop/render/intermediate/URIActionTestCase.java
@@ -26,9 +26,9 @@
 public class URIActionTestCase {
     @Test
     public void testID() {
-        URIAction action = new URIAction("uri", true);
-        URIAction action2 = new URIAction("uri", true);
-        URIAction action3 = new URIAction("uri2", true);
+        URIAction action = new URIAction("uri", true, null);
+        URIAction action2 = new URIAction("uri", true, null);
+        URIAction action3 = new URIAction("uri2", true, null);
         Assert.assertEquals(action.getID(), action2.getID());
         Assert.assertFalse(action.getID().equals(action3.getID()));
     }

diff --git a/fop/test/intermediate/basic-link_alttext.xml b/fop/test/intermediate/basic-link_alttext.xml
@@ -0,0 +1,47 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  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.
+-->
+<!-- $Id$ -->
+<testcase>
+  <info>
+    <p>
+      This test checks a fo:basic-link in a span
+    </p>
+  </info>
+  <cfg>
+    <accessibility>true</accessibility>
+  </cfg>
+  <fo>
+    <fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format" xmlns:fox="http://xmlgraphics.apache.org/fop/extensions">
+      <fo:layout-master-set>
+        <fo:simple-page-master page-width="8.5in" page-height="11in" master-name="Page">
+          <fo:region-body region-name="Body"/>
+        </fo:simple-page-master>
+      </fo:layout-master-set>
+      <fo:page-sequence master-reference="Page">
+        <fo:flow flow-name="Body">
+          <fo:block>
+            <fo:basic-link external-destination="www.a.com" fox:alt-text="xxx">www.a.com</fo:basic-link>
+          </fo:block>
+        </fo:flow>
+      </fo:page-sequence>
+    </fo:root>
+  </fo>
+  <if-checks xmlns:nav="http://xmlgraphics.apache.org/fop/intermediate/document-navigation">
+    <eval expected="xxx" xpath="//nav:link/nav:goto-uri/@alt-text"/>
+  </if-checks>
+</testcase>