// call the diagram constructor to load diagram from a VSDX file
Diagram vsdxtopdf = new Diagram("sourfile.vsdx");

// Options when saving a diagram into the PDF format
PdfSaveOptions pdfOpts = new PdfSaveOptions();

// discard saving background pages of the Visio diagram
pdfOpts.setSaveForegroundPagesOnly(true);

// specify the quality of JPEG compression for images (if JPEG compression is used). Default is 95.
pdfOpts.setJpegQuality(100);

// specify default font name
pdfOpts.setDefaultFont("Arial");

// conformance level for generated PDF document.
pdfOpts.setCompliance(PdfCompliance.PDF_15);

// sets a digital signature details. If not set, then no signing will be performed.
pdfOpts.setDigitalSignatureDetails(new PdfDigitalSignatureDetails(cert, "Test Signing", "Aspose Office", DateTime.getNow(), PdfDigitalSignatureHashAlgorithm.SHA_256));

// set encription details
PdfEncryptionDetails encriptionDetails = new PdfEncryptionDetails("user password", "Owner Password", PdfEncryptionAlgorithm.RC_4_128);
pdfOpts.setEncryptionDetails(encriptionDetails);
// sets the number of pages to render in PDF.
pdfOpts.setPageCount(2);
// sets the 0-based index of the first page to render. Default is 0.
pdfOpts.setPageIndex(0);

// set page size
PageSize pgSize = new PageSize(PaperSizeFormat.A_1);
pdfOpts.setPageSize(pgSize);

// save in visio file into PDF
vsdxtopdf.save("UsePDFSaveOptions_Out.pdf", pdfOpts);