k2pdfopt: optimizes PDFs for viewing on e-readers

[pumpapa]

Yes indeed, your version works.
Thanks!

Originally Posted by willus

I only support the Linux binary builds from my web site, which were built July 18, 2020. I'm not sure where you got the Aug 26 build. Sounds like it's a bad binary.

[Mhmad]

Originally Posted by willus

I'm not sure exactly what you mean by the "page flipping order." Do you mean that in Arabic you'd like to put the pages in reverse order or process them in reverse order? You can process the pages of a PDF in reverse order using k2pdfopt like so:

k2pdfopt -p 100-1 ...

(If your PDF has 100 pages, for example.)

Thanks for your reply, but unfortunately that's not what I mean, I want them in the same order, what I mean is for example in English books when you want to go to next page you touch the right side of the screen & for the previous page you touch the left side of the screen,,, for Arabic books it's the opposite, if u want next page you are supposed to touch the left side of the screen, which is not the case because many Arabic books are formatted in the standard form so if you want next page you press the right side (which is supposed to be for the previous page in Arabic :/)

I know it's not a big deal, but it's annoying while reading, so if there is any solution I would be very grateful.

[j.p.s]

Your complaint is with your PDF reading platform, not the PDF file.

To get what you want, your best bet is to reverse the page order in the PDF.

[willus]

Originally Posted by Mhmad

Thanks for your reply, but unfortunately that's not what I mean, I want them in the same order, what I mean is ...

You say that's not what you mean but I think j.p.s. is right. Reversing the page order would do exactly what you want on a left-to-right e-reader.

[willus]

I've put a Linux aarch64 (arm64) binary on my download page. If anybody has a chance to try it out and confirm that it runs, please let me know (it's cross-compiled and I do not have a platform to test it on).

[Mhmad]

Originally Posted by j.p.s

Your complaint is with your PDF reading platform, not the PDF file.

To get what you want, your best bet is to reverse the page order in the PDF.

Thank you for your reply,
Yes I see but the book will open on the last page then I must go manually to the end of the book (which is know the first page) to start reading,
For me I'm totally fine with that but the problem that I post the edited books sometimes in telegram group and that wouldn't be entirely acceptable with general audience,
Anyway thank you very much for your help

[Mhmad]

Originally Posted by willus

You say that's not what you mean but I think j.p.s. is right. Reversing the page order would do exactly what you want on a left-to-right e-reader.

Yes it seems the only valid solution, except like I told j.p.s.that I must start the book from the end.
Thank you for your help & effort

[schezuk]

As some people may not be accustomed to TTB-RTL text in mainland China, or LTR-TTB text in other regions, it may be convient to Text Reflow from one way to another. E.g.



By text reflowing it does not only mean to arrange text elements, which may be easily done by many other softwares, but to re-arrange text in scanned images.

It may be solved like this. Just rotate every square-shaped character detected 90 degree clockwise/counter-clockwise, and leave other characters be.

A workaround in similar principle for text element has been figured out by using a dedicated font with Chinese characters rotated. See LTR to TBRTL.

[modified]

Hi everyone

The device I'm using is a Kindle Paperwhite 5 (2021). The output I'm getting from k2pdfopt is bettter for reading on the PW except that when compared to the original, the text rendered is very "jagged"? For comparison, please see the screenshots attached.

I've tried different permutations of the command line options but could not improve the rendering on the PW.

./k2pdfopt Editorial.pdf -ui- -x -mt 0.8 -mb 0.5 -fc- -mc -odpi 300


Version used:
k2pdfopt v2.53 (w/MuPDF,DjVuLibre,OCR) (c) 2020, GPLv3, http://willus.com
Compiled Jul 18 2020 with Gnu C v8.2.0 for OS/X on x64.

The source pdf is here at http://drukjournal.bt/wp-content/upl.../Editorial.pdf

There is also a minor problem with the bullet items but I can live with it.

Suggestions on how to improve the text will be really appreciated.

[schezuk]

As some people may not be accustomed to TTB-RTL text in mainland China, or LTR-TTB text in other regions, it may be convient to Text Reflow from one way to another. E.g.
image
By text reflowing it does not only mean to arrange text elements, which may be easily done by many other softwares, but to re-arrange text in scanned images.
It may be solved like this. Just rotate every square character detected 90 degree clockwise/counter-clockwise, and leave other characters be.

[schezuk]

As some people may not be accustomed to TTB-RTL text in mainland China, or LTR-TTB text in other regions, it may be convient to Text Reflow from one way to another.

By text reflowing it does not only mean to arrange text elements, which may be easily done by many other softwares, but to re-arrange text in scanned images.

It may be solved like this. Just rotate every square character detected 90 degree clockwise/counter-clockwise, and leave other characters be.

[schezuk]

more details
github koreader issue 8969

[willus]

Originally Posted by schezuk

As some people may not be accustomed to TTB-RTL text in mainland China, or LTR-TTB text in other regions, it may be convient to Text Reflow from one way to another. ...

Seems like maybe this is a misplaced post? Should it be in a KO Reader thread?

[willus]

Originally Posted by modified

The device I'm using is a Kindle Paperwhite 5 (2021). The output I'm getting from k2pdfopt is bettter for reading on the PW except that when compared to the original, the text rendered is very "jagged"? For comparison, please see the screenshots attached...

I've tried different permutations of the command line options but could not improve the rendering on the PW.

./k2pdfopt Editorial.pdf -ui- -x -mt 0.8 -mb 0.5 -fc- -mc -odpi 300

Based on your posted screenshot of the Kindle Paperwhite 5, which shows the visible part of the PDF to be 1174 x 1554 pixels, it looks like the Paperwhite 5 is using the same display size/resolution as the Kindle Oasis 2, so you should use -dev ko2 (Kindle Oasis 2) for your screen, and also drop the "-odpi 300":

./k2pdfopt Editorial.pdf -ui- -x -mt 0.8 -mb 0.5 -fc- -mc -dev ko2

If you still aren't happy with that you can try adding -dr <xx> where <xx> is some number above 1.0 to increase the resolution of the bitmap in the output PDF even further, e.g. for a factor of 2 higher resolution:

./k2pdfopt Editorial.pdf -ui- -x -mt 0.8 -mb 0.5 -fc- -mc -dev ko2 -dr 2

[schezuk]

Originally Posted by willus

Seems like maybe this is a misplaced post? Should it be in a KO Reader thread?

They told me that this feature relies on Upstream library support, namely K2pdfopt.