Source code of the well-known PDFCreator from pdfforge, a free virtual-printer application: install it once and any application's own Print dialog can output directly to PDF. Supports merging and reordering pages, password and digital-signature protection, PDF/A archival compliance, custom cover pages, and automated post-processing actions (FTP upload, email delivery, custom scripting) triggered on every conversion. Widely used as a default 'print to PDF' tool on Windows.