Signature field flattening is not working

[matpag]

I'm using this code in my app to flatten a PDF with signatures added.

PdfiumCore pdfiumCore = new PdfiumCore(context);
ParcelFileDescriptor pfd = ParcelFileDescriptor.open(myFile, ParcelFileDescriptor.MODE_READ_ONLY);
PdfDocument pdfDocument = pdfiumCore.newDocument(pfd);

pdfiumCore.openPage(pdfDocument, page);

int width = pdfiumCore.getPageWidthPoint(pdfDocument, page);
int height = pdfiumCore.getPageHeightPoint(pdfDocument, page);

Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
pdfiumCore.renderPageBitmap(pdfDocument, bitmap, page, 0, 0, width, height);

But the resulting image created from the bitmap object won't have the signature fields drawn. Can i do something to add those signature fields to the flattening process?

Thanks
Mat

[barteksc]

Creating bitmap doesn't flatten pdf document. There is method for flattening in Pdfium, but it's not exposed in Java.

[matpag]

I thought renderPageBitmap performed flattening + conversion to Bitmap all togheter.

What is the corresponding C++ method in the library to do this? (i don't know too much about C++ but if it's not too hard i can try to create a PR with a wrapper function for this feature)

PS: i've found it, should be this if i'm not wrong

[matpag]

I've performed some researches and work, i've created a new method and in the last part of it (following the renderPageBitmap code) I've added the central lines.

....
FPDFBitmap_FillRect( pdfBitmap, baseX, baseY, baseHorSize, baseVerSize,
                     0xFFFFFFFF); //White

//flat the page before proceeding with Bitmap creation
const int result = FPDFPage_Flatten(page, flatType);
if (result == FLATTEN_FAIL){
    jniThrowException(env, "com/shockwave/pdfium/PdfiumCore", "PDF flattening has failed.");
}

FPDF_RenderPageBitmap( pdfBitmap, page,
                       startX, startY,
                       (int)drawSizeHor, (int)drawSizeVer,
                       0, flags );
.....

i've tried with 2 different sample PDF with form fields filled, but a the end i only get a PDF without them.
Maybe i need to save and reopen the document?
Any suggestions?

[barteksc]

Sorry, I forgot to mention that you should try using last parameter of .renderPage() method, which is boolean renderAnnot. It should render annotations and forms.

[matpag]

Lol, now it's working fine passing true to the renderAnnot param.
I've wasted an evening working on something which was already working XD (at least i've learned something new 😋)
Btw thank you man, i've created a PR to update the example code to avoid future issues on the same thing

[barteksc]

Sorry not mentioning it immediately. Thanks for update, I will pull it.