PPTX to PDF: Some images lose their transparency, show a black background instead (Java)

Dear aspose support,
one of our customers informed me that upon generating a PDF out of a PPTX, some images lose their transparency and instead show a black background. i did some research but it’s still not quite clear why this happens. so i hope you can help me.

the code that converts the pptx to pdf:

private ByteArrayContent generatePdfContent(Presentation presentation) {
PdfOptions options = new PdfOptions();
options.setSaveMetafilesAsPng(true);
options.setTextCompression(PdfTextCompression.Flate);
options.setCompliance(PdfCompliance.Pdf15);

ByteArrayOutputStream pdfOutputStream = new ByteArrayOutputStream();
presentation.save(pdfOutputStream, SaveFormat.Pdf, options);
return new ByteArrayContent(pdfOutputStream.toByteArray(), "application/pdf");

}

example pptx:testpres_17062020.zip (324.2 KB)

hope you can help me, thanks in advance!

@chamcham123,

I have worked with sample presentation and have been able to reproduce the problem. An issue with ID SLIDESJAVA-38133 has been created to resolve the issue in our issue tracking.

testpres_17062020.pptx.pdf (262.9 KB)

The issues you have found earlier (filed as SLIDESJAVA-38133) have been fixed in this update.