#79 - Accessible bookmarks implementation and testcase.

danfickle · Jan 28, 2019 · abd36ee · abd36ee
1 parent 6cc4f40
commit abd36ee
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Showing 6 changed files with 58 additions and 6 deletions.
diff --git a/...mltopdf-examples/src/main/java/com/openhtmltopdf/testcases/pdfua/PdfUaTestcaseRunner.java b/...mltopdf-examples/src/main/java/com/openhtmltopdf/testcases/pdfua/PdfUaTestcaseRunner.java
@@ -48,5 +48,6 @@ public static void main(String... args) throws Exception {
         run("running");
         run("lists");
         run("tables");
+        run("bookmarks");
     }
 }
diff --git a/openhtmltopdf-examples/src/main/resources/testcases/pdfua/bookmarks.html b/openhtmltopdf-examples/src/main/resources/testcases/pdfua/bookmarks.html
@@ -0,0 +1,23 @@
+<html>
+<head>
+<title>Simple PDF/UA Bookmarks sample</title>
+<style>
+@page {
+  size: A4;
+  margin: 0;
+}
+</style>
+<bookmarks>
+  <bookmark name="Outer" href="#secondpage">
+    <bookmark name="Inner" href="#thirdpage"/>
+  </bookmark>
+</bookmarks>
+</head>
+<body>
+   <div style="width: 100%; height: 20px; background-color: transparent; page-break-after: always;"></div>
+
+   <div id="secondpage" style="background-color: red; height: 10px;"></div>
+   <div style="width: 100%; height: 20px; background-color: transparent; page-break-after: always;"></div>
+   <div id="thirdpage" style="background-color: green; height: 10px;"></div>
+</body>
+</html>
diff --git a/...htmltopdf-pdfbox/src/main/java/com/openhtmltopdf/pdfboxout/PdfBoxAccessibilityHelper.java b/...htmltopdf-pdfbox/src/main/java/com/openhtmltopdf/pdfboxout/PdfBoxAccessibilityHelper.java
@@ -267,6 +267,20 @@ public String toString() {
     private static class FigureContentItem extends GenericContentItem {
     }
 
+    /**
+     * Given a box, gets its structual element.
+     */
+    public static PDStructureElement getStructualElementForBox(Box targetBox) {
+        if (targetBox != null &&
+            targetBox.getAccessibilityObject() != null &&
+            targetBox.getAccessibilityObject() instanceof AbstractStructualElement) {
+
+            return ((AbstractStructualElement) targetBox.getAccessibilityObject()).elem;
+        }
+
+        return null;
+    }
+
     public void finishPdfUa() {
         PDStructureTreeRoot root = _od.getWriter().getDocumentCatalog().getStructureTreeRoot();
         if (root == null) {
@@ -524,8 +538,11 @@ private void finishTreeItem(AbstractTreeItem item, AbstractStructualElement pare
             // which contains other structual elements or content items (text).
             GenericStructualElement child = (GenericStructualElement) item;
 
-            if (child.children.isEmpty()) {
+            if (child.children.isEmpty() &&
+                (child.box.getElement() == null || !child.box.getElement().hasAttribute("id"))) {
                 // There is no point in outputting empty structual elements.
+                // Exception is elements with an id which may be there to
+                // use as a link or bookmark destination.
                 return;
             }
 

diff --git a/openhtmltopdf-pdfbox/src/main/java/com/openhtmltopdf/pdfboxout/PdfBoxBookmarkManager.java b/openhtmltopdf-pdfbox/src/main/java/com/openhtmltopdf/pdfboxout/PdfBoxBookmarkManager.java
@@ -7,6 +7,7 @@
 import java.util.logging.Level;
 
 import org.apache.pdfbox.pdmodel.PDDocument;
+import org.apache.pdfbox.pdmodel.documentinterchange.logicalstructure.PDStructureElement;
 import org.apache.pdfbox.pdmodel.interactive.documentnavigation.destination.PDDestination;
 import org.apache.pdfbox.pdmodel.interactive.documentnavigation.destination.PDPageFitHeightDestination;
 import org.apache.pdfbox.pdmodel.interactive.documentnavigation.destination.PDPageXYZDestination;
@@ -68,9 +69,10 @@ private void writeBookmarks(RenderingContext c, Box root, PDOutlineNode parent,
     private void writeBookmark(RenderingContext c, Box root, PDOutlineNode parent, Bookmark bookmark) {
         String href = bookmark.getHRef();
         PDPageXYZDestination target = null;
-
+        Box box = null;
+
         if (href.length() > 0 && href.charAt(0) == '#') {
-            Box box = _sharedContext.getBoxById(href.substring(1));
+            box = _sharedContext.getBoxById(href.substring(1));
 
             if (box != null) {
                 target = createBoxDestination(c, _writer, _od, _dotsPerPoint, root, box);
@@ -84,6 +86,12 @@ private void writeBookmark(RenderingContext c, Box root, PDOutlineNode parent, B
         PDOutlineItem outline = new PDOutlineItem();
         outline.setDestination(target == null ? _defaultDestination : target);
         outline.setTitle(bookmark.getName());
+
+        PDStructureElement se = PdfBoxAccessibilityHelper.getStructualElementForBox(box);
+        if (se != null) {
+            outline.setStructureElement(se);
+        }
+
         parent.addLast(outline);
         writeBookmarks(c, root, outline, bookmark.getChildren());
     }

diff --git a/openhtmltopdf-pdfbox/src/main/java/com/openhtmltopdf/pdfboxout/PdfBoxFastOutputDevice.java b/openhtmltopdf-pdfbox/src/main/java/com/openhtmltopdf/pdfboxout/PdfBoxFastOutputDevice.java
@@ -846,14 +846,17 @@ public void start(Document doc) {
     }
 
     public void finish(RenderingContext c, Box root) {
-        _bmManager.loadBookmarks();
-        _bmManager.writeOutline(c, root);
         processControls();
         _linkManager.processLinks();
 
         if (_pdfUa != null) {
             _pdfUa.finishPdfUa();
         }
+
+        // Bookmarks must come after PDF/UA structual tree creation
+        // because bookamrks link to structual elements in the tree.
+        _bmManager.loadBookmarks();
+        _bmManager.writeOutline(c, root);
     }
 
     @Override

diff --git a/openhtmltopdf-pdfbox/src/main/java/com/openhtmltopdf/pdfboxout/PdfBoxRenderer.java b/openhtmltopdf-pdfbox/src/main/java/com/openhtmltopdf/pdfboxout/PdfBoxRenderer.java
@@ -697,7 +697,7 @@ private void addPdfUaXMPSchema(PDDocument doc) {
         {
             PDDocumentCatalog catalog = doc.getDocumentCatalog();
             String lang = _doc.getDocumentElement().getAttribute("lang");
-            catalog.setLanguage(lang != null ? lang : "EN-US");
+            catalog.setLanguage(!lang.isEmpty() ? lang : "EN-US");
             catalog.setViewerPreferences(new PDViewerPreferences(new COSDictionary()));
             catalog.getViewerPreferences().setDisplayDocTitle(true);