k2pdfopt: optimizes PDFs for viewing on e-readers

[droopy]

I just learned about this a few days ago and am so excited to get it working on my Linux computer with some GUI.
Willus, just wanted to tell you that the online K2PDFOPT On-line link (http://convert-kindle.com/) on https://www.willus.com/k2pdfopt/contrib/ is dead.

[willus]

Originally Posted by droopy

I just learned about this a few days ago and am so excited to get it working on my Linux computer with some GUI.
Willus, just wanted to tell you that the online K2PDFOPT On-line link (http://convert-kindle.com/) on https://www.willus.com/k2pdfopt/contrib/ is dead.

Thanks. Fixed. Wallauer's site went away, too.

[droopy]

So glad that the college's computer lab is still open at this time.
So glad that I was able to run both k2pdfopt and k2pdfopt GUI 2.0. (Like when I run k2Updater (in the k2pdfopt GUI 2.0 folder), whech says that the application is blocked)

[droopy]

Hi Willus,
I've tried k2pdfopt_GUI_2.0 but I stick with your program because of the preview. The GUI_2.0 program doesn't have a preview.

A program called "GUI" should not be removing "pictures" (the preview box) from a program that it's supposed to improve.

[Kule]

Hello again Willys,

I encountered issue with one book that has white margins every page (placed left on the odd pages, and right on the even pages).

I tried to crop these and to preserve page count, but no luck so far.
Here are the settings I used:
https://ibb.co/hK732gy

I sent you the source file on PM the following:
1) original PDF file (4 pages)
2) my converted result after additional tinkering with crop settings Adobe DC Pro (as it looks on the Sony DPT RP1).

To conclude, which settings should I use in order to stretch pages without any white margins on both sides (preferably to preserve original page count)?

Thanks for help

[willus]

Originally Posted by Kule

Hello again Willys,

I encountered issue with one book that has white margins every page (placed left on the odd pages, and right on the even pages).

I tried to crop these and to preserve page count, but no luck so far.
Here are the settings I used:
https://ibb.co/hK732gy

I sent you the source file on PM the following:
1) original PDF file (4 pages)
2) my converted result after additional tinkering with crop settings Adobe DC Pro (as it looks on the Sony DPT RP1).

To conclude, which settings should I use in order to stretch pages without any white margins on both sides (preferably to preserve original page count)?

Thanks for help

Sorry for taking so long to get back to you. Best bet is to crop out the footer and side margins of each page so that the cropped page fits your device better. I used one crop rectangle for odd pages and a different one for even pages. Then use the -mode fitpage (as you already figured out) so that you preserve the page count. See attached screenshot, marked source, and conversion file.

[Kule]

Thank you very much it helped and solved the issue!

[nlundberg]

This is such great piece of application, thanks! Its so nice to be able to read anything I want on my arcane e-reader (cybook odyssey HD frontlight).

Some questions (for command line/osx):

If I want to do another pass with some other options, for example ocr, but not wrap/reflow, what options should I set?

Can K2PDFOPT be used to create a TOC?

I am converting a DJVU book, btw.

[willus]

Originally Posted by nlundberg

If I want to do another pass with some other options, for example ocr, but not wrap/reflow, what options should I set?

Can K2PDFOPT be used to create a TOC?

I am converting a DJVU book, btw.

You can always do multiple passes. Just run k2pdfopt on the file that it just created. You don't have to do a second pass just for OCR. You can just turn on OCR on whatever conversion you do. If you don't want re-flow, use -wrap- as the command-line option to turn it off.

Yes, you can definitely add a TOC. See the the -toclist option in the command-line usage help page. You can supply it with a text file that you can create in a simple text editor (e.g. Notepad in Windows).

[Shohreh]

Hello,

For enhanced reading of PDFs on an e-reader, I'd like to 1) remove the margins, 2) turn the pages into pictures (PNG), and 3) merge all those pictures back into a PDF file.

For Step 1, I tried cpdf, but I can't figure it out (-mediabox, -cropbox, -hard-box).

Alternatively, it looks like k2pdfopt can do it (-cbox, -grid): Is it correct?

I need a Windows32 application, ideally, a single EXE instead of eg. Java. Hence my not looking at Briss.

Thank you.

[willus]

Originally Posted by Shohreh

Hello,

For enhanced reading of PDFs on an e-reader, I'd like to 1) remove the margins, 2) turn the pages into pictures (PNG), and 3) merge all those pictures back into a PDF file.

For Step 1, I tried cpdf, but I can't figure it out (-mediabox, -cropbox, -hard-box).

Alternatively, it looks like k2pdfopt can do it (-cbox, -grid): Is it correct?

I need a Windows32 application, ideally, a single EXE instead of eg. Java. Hence my not looking at Briss.

Thank you.

Yes, I think k2pdfopt checks off all of your boxes. Select your source file, then check off the crop areas check box and click "select" to choose your crop region to remove the margins. For conversion mode, select "fitpage", and then uncheck the "Native PDF output" if you want the output to be PNG bitmaps assembled into the PDF (rather than the original PDF content). See attached screen shot. You might want to watch the video(s) from the help pages.

[Shohreh]

Thanks. I forgot to say I need to call it through the CLI in a batch script to trim a bunch of pages.

Would you have an example?

C:\k2pdfopt>k2pdfopt.exe /?

k2pdfopt v2.51a (w/MuPDF,DjVuLibre,OCR) (c) 2019, GPLv3, http://willus.com
    Compiled Jan  4 2019 with Gnu C (Mingw32) v7.3.0 for Win32 on i386.

 a. Autostraighten (-as)                 n. Native PDF output (-n)
 b. Bitmap type (-jpg,-png,-bpc)         o. Output name (-o)
bp. Break pages (-bp,-f2p)              oc. OCR (-ocr,-ocrvis,...)
 c. Color/Negative output (-c, -neg)    om. Output margins (-om)
co. Column detection (-col,-ch,...)      p. Page range (-p)
cs. Contrast/Sharpen (-cmax,-g,-s,-wt)  pd. Padding/Marking (-p[lrbt],-mc)
 d. Device selection (-dev,-h,-w,-dpi)   r. Right-to-left page scans (-r)
ds. Document scale factor (-ds)         rt. Rotate source page (-sr)
 f. Fit to single column (-fc)           s. Special (-de,-evl,-gs)
gt. Gap thresholds (-gt...)             sm. Show marked source (-sm)
 j. Justification (-j)                   u. Usage (command line opts)
 l. Landscape mode (-ls)                 v. Vertical spacing (-vb,-vs)
 m. Margin to ignore (-m)                w. Wrap/Reflow text (-wrap,-ws)
mo. Mode (-mode)                         x. Exit on completion (-x)

Selected options:  /?

[Shohreh]

The following doesn't do what I want, which is keep the original layout but simply remove the margins and widen the text to fit :

k2pdfopt input.pdf -m 0.8 -o output.pdf -p 30-40,70-75

[willus]

Originally Posted by Shohreh

The following doesn't do what I want, which is keep the original layout but simply remove the margins and widen the text to fit :

k2pdfopt input.pdf -m 0.8 -o output.pdf -p 30-40,70-75

Try this:

k2pdfopt -m 0.8 -mode fw -ls-

You can see what these options do on my command options listing page

PS. If you want to post a few pages from your source PDF file, I can verify what works best.

[Shohreh]

Thanks for the offer: https://we.tl/t-KA9InMaCCd

It looks much better. I just need to leave a bit more on the right, before merging the pages back into a single PDF.

k2pdfopt input.pdf -m 0.8 -mode fw -ls- -o output.pdf -p 30-40,70-75

--
Edit: While we're at it: Can k2pdfopt crop such and such page, and then turn them into pictures in place, without having to do this myself?

ie.
1. Use k2 to crop margins and rescale text
2. Export those pages
3. Convert to PNG
4. Convert to PDF
5. Merge all pages into hybrid PDF (text + pics)

Or maybe k2 can massage the PDF in such as way that there's simply no need to turn problematic pages into pictures (eg. tables, insets, etc.)?