K2pdfopt optimizes PDF/DJVU files for mobile e-readers (e.g. the Kindle) and smartphones. It works well on multi-column PDF/DJVU files and can re-flow text even on scanned PDF files. It can also be used as a general PDF copying/ cropping/re-sizing/OCR-ing manipulation tool. It can generate native or bitmapped PDF output, with an optional OCR layer.