Calling PDFNet.PDFDoc.pagePushFront() results in last page not being displayed on WebViewer

[Benjamin Roedell]

I'm trying to add cover page to a PDF before displaying it on the WebViewer.

All my code is available here: https://github.com/benrobot/PdfManipulation

This code:
var runCustomViewerCode = function(pdfDoc)
{
function* main()
{
...
console.log("doc pagecount BEFORE pagePushFront: ", currentPageCount);

doc.pagePushFront(coverPage);

currentPageCount = yield doc.getPageCount();
console.log("doc pagecount AFTER pagePushFront: ", currentPageCount);
return PDFNet.runGeneratorWithCleanup(main());
}

Results in this output:
doc pagecount BEFORE pagePushFront: 2
doc pagecount AFTER pagePushFront: 3


But this code:
runCustomViewerCode(pdfDoc).then(function(){
console.log("Page count BEFORE refreshAll: ", readerControl.docViewer.getPageCount());
// Refresh the cache with the newly updated document
readerControl.docViewer.refreshAll();

console.log("Page count BEFORE updateView: ", readerControl.docViewer.getPageCount());
// Update viewer with new document
readerControl.docViewer.updateView();
});

Results in this output:
Page count BEFORE refreshAll: 2
Page count BEFORE updateView: 2

How do I get my inserted to be recognized by the WebViewer?

[David Tippett]

Hi Benjamin,

In the current version of WebViewer refreshAll will only update the content of pages rather than the page structure. However, I agree this is confusing and we will change this in a future version.

In the meantime you can implement your use case in the following manner using CoreControls.Document.insertPages(). Note that in your index.html file you will want to pass useDownloader:false in the WebViewer constructor. This is generally necessary when using page operations within WebViewer.

Config.js:

(function() {

    $(document).on('documentLoaded', function() {

        PDFNet.initialize().then(function(){

            var doc = readerControl.docViewer.getDocument();

doc.getPDFDoc().then(function(pdfDoc){

console.log("Page count BEFORE ALL: ", readerControl.docViewer.getPageCount());

// note that requirePage is not necessary here without 

console.log("Page count BEFORE runCustomViewerCode: ", readerControl.docViewer.getPageCount());

// Run our script

runCustomViewerCode(pdfDoc).then(function(count){

// load the cover document

var partRetriever = new CoreControls.PartRetrievers.ExternalPdfPartRetriever("/resources/This_is_a_cover_page.pdf", {useDownloader: false});

var coverDoc = new CoreControls.Document(null, "pdf");

var coverDocReady = function() {

// copy page 1 from coverDoc to the beginning of doc

// insertPages will automatically update the structure in WebViewer

doc.insertPages(coverDoc, [1], 1).then(function() {

// Since pages changed before we still need to make sure all pages are redrawn

// Refresh the cache with the newly updated document

readerControl.docViewer.refreshAll();

// Update viewer with changes

readerControl.docViewer.updateView();

console.log("Page count after insertPages: ", readerControl.docViewer.getPageCount());

});

};

// Note: since initPDFWorkerTransports has already been called by WebViewer constructor and PDFNet.initialize

// it doesn't require any arguments.

coverDoc.loadAsync(partRetriever, coverDocReady, {workerTransportPromise: CoreControls.initPDFWorkerTransports()});

});

});

        });

    });

    var runCustomViewerCode = function(pdfDoc)

    {

        function* main()

        {

            console.log("Hello WebViewer!");

            var doc = pdfDoc;

            doc.lock();

            

            // Example 1) Add text stamp to all pages, then remove text stamp from odd pages. 

            try 

            {

                // start stack-based deallocation with startDeallocateStack. Later on when endDeallocateStack is called,

                // all objects in memory that were initialized since the most recent startDeallocateStack call will be

                // cleaned up. Doing this makes sure that memory growth does not get too high.

                yield PDFNet.startDeallocateStack();

                var stamper = yield PDFNet.Stamper.create(PDFNet.Stamper.SizeType.e_relative_scale, 0.5, 0.5); //Stamp size is relative to the size of the crop box of the destination page

                stamper.setAlignment(PDFNet.Stamper.HorizontalAlignment.e_horizontal_center, PDFNet.Stamper.VerticalAlignment.e_vertical_center);

                var redColorPt = yield PDFNet.ColorPt.init(1, 0, 0);

                stamper.setFontColor(redColorPt);

                var pgSet = yield PDFNet.PageSet.createRange(1, (yield doc.getPageCount()));

                stamper.stampText(doc, "If you are reading this\nthis is an even page", pgSet);

                var oddPgSet = yield PDFNet.PageSet.createFilteredRange(1, (yield doc.getPageCount()), PDFNet.PageSet.Filter.e_odd);

                // delete all text stamps in odd pages

                PDFNet.Stamper.deleteStamps(doc, oddPgSet);

                console.log("Sample 1 complete");

                yield PDFNet.endDeallocateStack();

            } catch (err) {

                console.log(err.stack)

                ret = 1;

            }

            

        }

        return PDFNet.runGeneratorWithCleanup(main());

    }

})();

//# sourceURL=config.js

Best Regards,

David

[Benjamin Roedell]

Thank you very much.  That worked like a charm.