To avoid OutOfMemory problems when rendering Powerpoint presentations we have implemented batch based rendering using Aspose.Slides and Aspose.Pdf.
Our rendering code looks as follows:
Presentation doc = new Presentation(filename);
PdfOptions options = new PdfOptions();
options.setSaveMetafilesAsPng(false);
options.setSufficientResolution(128f);
INotesCommentsLayoutingOptions notesOptions = options.getNotesCommentsLayouting();
notesOptions.setNotesPosition(NotesPositions.BottomFull);
Document combinedPdf = new Document(); // aspose.pdf.Document
int batchSize = 5;
int totalSlides = doc.getSlides().size();
int batches = (int) Math.ceil( ((double) totalSlides) / batchSize);
for(int batch = 1; batch <= batches; batch++) {
int slideStart = ((batch-1) * batchSize) + 1;
int slideEnd = (batch == batches) ? totalSlides : batch * batchSize ;
int[] slides = IntStream.rangeClosed(slideStart, slideEnd).toArray();
ByteArrayOutputStream batchOutputStream = new ByteArrayOutputStream();
doc.save(batchOutputStream, slides, SaveFormat.Pdf, options);
InputStream batchInputStream = new ByteArrayInputStream(batchOutputStream.toByteArray());
Document batchDocument = new Document(batchInputStream);
combinedPdf.getPages().add(batchDocument.getPages());
}
combinedPdf.save(outputFilename);
The batch functionality works very well and we are no longer seeing memory problems. We are however running into a problem with page numbers. The page numbers keep resetting for each batch. When using a batch size of 5 the page number will reset to 1 on slide 6, 11, 16 etc.
This behaviour can only be observed when using notesOptions.setNotesPosition(NotesPositions.BottomFull), if we set notesOptions.setNotesPosition(NotesPositions.None) it seems to work as expected.
Using NotesPositions.None is however not an option, we need to print with speaker notes. How can we keep the correct page numbers while showing speaker notes?
Here are examples of rendered presentations:
Test presentation: page-number-test.pptx.zip (50.4 KB)