Changing zoom level of all links in a PDF document - pdf

Question

I'd like to change zoom level in links in PDF files using iText 7. There are already solutions for legacy iText 5 (1, 2) but there is none for iText 7.
There are many ways links can work (it can be even JavaScript code) but now I'm interested in GoTo actions (i.e. /XYZ, /Fit and others described in ISO 32000-1, Table 151).
My current code locates GoTo actions but I don't know what the destination of a link is (such as page number, coordinates for XYZ zoom type). How do I get the destination of a link? Or am I missing something and that problem can be solved in a different way?
for (int i = 1; i <= numberOfPages; i++) {
PdfPage page = document.getPage(i);
List<PdfAnnotation> annots = page.getAnnotations();
if (annots.isEmpty()) {
continue;
}
for (int j = 0; j < annots.size(); j++) {
PdfAnnotation annot = annots.get(j);
if (annot == null) {
continue;
}
PdfDictionary action = annot.getPdfObject()
.getAsDictionary(PdfName.A);
if (action == null ||
!PdfName.GoTo.equals(action.get(PdfName.S))) {
continue;
}
annot.remove(PdfName.A);
// here I need the destination of action
int pageNumber = ???
Rectangle cropBox = document.getPage(pageNumber).getCropBox();
PdfAction goToAction = PdfAction.createGoTo(PdfExplicitDestination.createXYZ(
document.getPage(pageNumber), cropBox.getLeft(), cropBox.getTop(), 2F));
annot.put(PdfName.A, goToAction.getPdfObject());
}
}
UPDATE Working Code
I managed to deal with GoTo actions - both explicit and of type Named Destination. It works on some pdf file I tested the code against but I'm not sure whether it covers all the possible cases
Note:
When dealing with named destination I create explicit destination and then use it instead of named destination. The thing is, however, that named destination still exists in pdf. How do I get rid of it? In iText 5 there was a method consolidateNamedDestinations() which seems to do what I need:
Replaces all the local named links with
the actual destinations.
Please see my code:
try (document) {
Map<String, PdfObject> namedDests = null;
for (int i = 1; i <= document.getNumberOfPages(); i++) {
List<PdfAnnotation> annots = document.getPage(i).getAnnotations();
if (annots.isEmpty()) {
continue;
}
for (PdfAnnotation annot : annots) {
if (annot == null) {
continue;
}
PdfDictionary action = annot.getPdfObject()
.getAsDictionary(PdfName.A);
if (action == null) {
continue;
}
PdfName actionType = action.getAsName(PdfName.S);
if (PdfName.Link.equals(actionType)) {
throw new UnsupportedOperationException(
"Action of type " + action);
} else if (!PdfName.GoTo.equals(actionType)) {
continue;
}
PdfArray dest = action.getAsArray(PdfName.D);
// explicit GoTO case
if (dest != null) {
changeZoomLevel(document, annot, dest.getAsDictionary(0));
continue;
}
// Named Destination case
if (namedDests == null) {
namedDests = document.getCatalog()
.getNameTree(PdfName.Dests)
.getNames();
}
String namedDest = action.getAsString(PdfName.D)
.getValue();
PdfObject d = namedDests.get(namedDest);
PdfDictionary dict = null;
if (d instanceof PdfDictionary) {
PdfArray arr = (PdfArray) ((PdfDictionary) d).get(PdfName.D);
dict = arr.getAsDictionary(0);
} else if (d instanceof PdfArray) {
dict = ((PdfArray) d).getAsDictionary(0);
}
changeZoomLevel(document, annot, dict);
}
}
}
private static void changeZoomLevel(PdfDocument document,
PdfAnnotation annot, PdfDictionary dest) {
annot.remove(PdfName.A);
annot.put(PdfName.A, createPdfAction(document, dest));
}
private static PdfObject createPdfAction(PdfDocument document, PdfDictionary dest) {
PdfPage actionPage = document.getPage(dest);
Rectangle cropBox = actionPage.getCropBox();
return PdfAction.createGoTo(PdfExplicitDestination.createXYZ(
actionPage, cropBox.getLeft(), cropBox.getTop(), 1.5F)).getPdfObject();
}