OVERVIEW



e.g.
open source






Note to MS Word users:
PDF Conversion Tips





IT TURNS THIS . . .



(8.5 x 11 PDF or DJVU file)		    . . . INTO THIS.



(6-inch reader screen)		      . . . OR THIS.



(4-inch smartphone screen)



  
MS Windows integrated GUI front-end
Unsolicited comments from k2pdfopt users (refresh the page to change the comments):



         “… thank you very much for creating and making this wonderful tool available … Keep up the awesome work!” — September 7, 2016         


         “Recently I found k2pdf to optimize pdfs for viewing on tablets or ereaders. I am mightily impressed and would like to thank you very much for making it available. I am using it regularly.” — December 7, 2014         



LATEST NEWS


3 Aug 2019    My site (willus.com) now offers SSL/https connectivity. Apparently this happened without my being notified, at no charge to me, which is nice. As a result, today I configured my site (and my backup site willus.org) to automatically re-direct http requests to https requests. Enjoy the added security!
5 Jan 2019    K2pdfopt V2.51 A for MS Windows RELEASED. Fixes a bug displaying PDF file information in the MS Windows GUI. The Download Page now shows v2.51a. The MS Windows binaries will show V2.51 a, But the Linux and OSX binaries will show V2.51 since they are not affected by the bug. See details in thek2pdfopt version history.
4 Jan 2019    K2pdfopt v2.51Released. This fixes an issue in V2.50 where the Tesseract OCR would not run on modern PCs and enhances the accuracy of the party The Tesseract V4.0.0 OCR. See details in thek2pdfopt version history.
31 Dec 2018    I’ve posted some k2pdfopt beta Windows builds (link since removed) due to reports of v2.50 Tesseract OCR failing on machines with AVX-capable CPUs (which includes most modern CPUs since Sandybridge). If some people could give me feedback on whether the beta version Tesseract OCR works on their AVX-capable CPU, that would be helpful. If you have time, please try all three versions.
27 Dec 2018    The major enhancement in this release is compiling in The Tesseract V4.0.0 library. Most other third-party libraries have also been updated to recent releases. See details in thek2pdfopt version history.
15 Oct 2017    Added a new video to the Mac OSX help page demonstrating how to download and run k2pdfopt in OSX Sierra.
20 May 2017    This Revision adds bitmap file output (see-o option), dewarping (like ScanTailor, see -dw option), better auto-cropping (-ac option), and Kobo Aura One device dimensions. See details in thek2pdfopt version history.
25 Feb 2017    K2pdfopt v2.41 released. This is mostly a library update, with one minor new feature (erosion filter to thicken text). See details in the k2pdfopt version history.
1 Jan 2017    K2pdfopt V2.40 released. Tesseract OCR processing is now multi-threaded and so runs significantly on modern, multi-threaded CPUs like Intel’s Core-i7. See details in thek2pdfopt version history.
26 Nov 2016    K2pdfopt V2.36 released. This is a mostly bug-fix release with some minor new featuresk2pdfopt version history.
29 Oct 2016    Added SHA-256 hash code links to the download page. You can hover over the buttons or click the “sha-256” links below them.
22 Oct 2016    K2pdfopt V2.35 released. This is a mostly bug-fix release with some minor new features and updated libraries compiling platforms. See details in thek2pdfopt version history.
10 Oct 2016    For now, if you want to run k2pdfopt in Mac OSX Sierra, you’ll need versions that are not compressed with UPX, which is broken in Sierra(22 Oct 2016 — You can now get V2.35 which works in Sierra.)
21 Mar 2016    K2pdfopt v2.34b released. This release fixes two more MS Windows bugs. The Linux and Mac versions are not affected (still v2.34a).
[… more news]






ABOUT K2PDFOPT (MORE DETAIL)



Kindle’s
re-flow text lines, even on scanned documents
this help page






embed OCR text
native PDF






HOW TO USE K2PDFOPT


   No install is required and no extra files or packages are necessary to run k2pdfopt (Mac/Linux users please see the mac install notes or linux install notes). Just drag and drop your PDF/DJVU file icon onto the k2pdfopt icon to convert it. You will be prompted for conversion Options (as of V1.16).clickConvert All Files (MS Windows GUI) or Press <Enter> to convert the file using the default settings. A new PDF file with _k2opt at the end of the name will be created. The output file is optimized for viewing on Kindles and other mobile readers with 6-inch screens (if the settings are not customized). You can also drop a folder full of PDF/DJVU files onto the k2pdfopt icon to batch process them. You can even drop a folder full of bitmap images to have them converted into a single PDF as if they were pages of a PDF file (page ordering will be alphabetical by file name).



k2pdfopt help page






view native PDF files






MORE EXAMPLES


Example Type Original

File 		Default Conversion

optimized for 6-inch

screen at 167 dpi 		Smartphone Conversion

(-odpi 250)

optimized for 4-inch

screen at 250 dpi
Text re-flow
Text re-flow on

scanned pages
Four-column

(must use -col 4)



K2PDFOPT REVIEWS / BLOGS / FORUMS / TWEETS


    The 5-10-16    e-okuyucu.com (In Turkish)
    The 3-18-16    epubor.com (nice tutorial)
    The 7-10-15    blog.the-ebook-reader.com
    The 6-14-15    MacWorld.co.uk
    The 7-22-14    VidaSemPapel.com.br (In Portuguese)
    The 6-20-14    ghacks.net
    The 4-11-14    betanews.com
    The 4-11-14    TrishTech.com
    The 3-14-14    Dr. Simon Bance
    The 1-28-13    Intelligent Rumblings
    The 1-7-13    Net Buffalo (In Japanese)
    The 12-1-12    blog.trufanov.com (In Russian)
    The 11-4-12    abstractmodem.com (archived)
    The 9-20-12    ozgurlukicin.org (in Turkish)
    The 6-27-12    equiscentrico.com (in Spanish)
    The 6-26-12    ketabkhan.info (in Persian)
    The 1-4-12    TechLogon.com
    The 11-9-11    Ś wiat Czytnikow (in Polish)
    The 11-5-11    tivasyk.info (in Ukrainian)
   
    The 11-1-11    WMLCloud.com
    The 10-31-11    linospapa.blogspot.com (in Greek)
    The 10-27-11    Steve Gibson’s Security Now #324
    The 10-21-11    addictivetips.com
    The 10-12-11    Paper4Kindle (in Chinese)
    (varies)    mobileread.com forums
    The 9-7-11    habrahabr.ru (in Russian)
    The 8-4-11    steepbend.ru (in Russian)
    The 8-3-11    ssnjara.wordpress.com (in Croatian)
    The 8-2-11    howtogeek.com (note comments from “willus”)
    The 7-30-11    artiss.co.uk
    The 7-30-11    ideasfor.info (in Russian)
    The 7-27-11    guidingtech.com (note comments from “willus”)
    The 7-22-11    blog.rgub.ru (in Russian)
    The 7-22-11    aldus2006.typepad.fr (in French)
    The 7-22-11    korben.info (in French)
    The 7-21-11    lifehacker.ru (in Russian)
    The 7-20-11    redferret.net
    The 7-19-11    freewaregenius.com (full review)



OTHER PDF/CONVERTING SOFTWARE



PDF Conversion Tips






RECOMMENDED WINDOWS PDF/E-BOOK READER: SUMATRA



Krzysztof Kowalczyk’s
Sumatra PDF reader