Actually having just looked again, I think the optimize() method does get called on saving the document. But the text stream still doesn't get compressed (including in release mode). So I guess this is more a lopdf thing.

Hi. I noticed that even after subsetting fonts with allsorts, the PDFs generated by genpdf are pretty big. lopdf::PdfDocumentReference has an optimize() method, which looks like it compresses streams (as well as deleting some redundant stuff from the doc). Whereas genpdf docs seem to just have uncompressed text streams. Would it be useful / possible to add something similar to genpdf? Thanks!