k2pdfopt: optimizes PDFs for viewing on e-readers

[willus]

Originally Posted by nook user

Great, thanks for the enormous job , Willus

But i have other question now
Let's assume, that we have page in this format:
========
Text
Picture (graphic) (table)
Text
=============

Is there any chance the picture or graphic or table to be stretched in landscape mode onto whole page and the text in the file to be in portrait mode...

In other words said - every one picture or graphic or table to be in landscape mode onto one whole page - for example

we have 2 pictures in the file on pages 4 and 8 -
Pages 4 and 8 will be converted automatically in landscape mode, showing only the pics...
Or we have to say, 3 pictures on page 5 - in this case, after conversion pages 5, 6 and 7 will be automatically re-shaped in landscape mode for the pictures on them....

Yes--it should be easy enough to add an option to put figures into landscape mode when their aspect ratio warrants it. I'll make a note of it.

[nook user]

Thanks mate!
You're my hero

[Cyga]

Hello, anyone know how to change reflow font size on Paperwhite 2?

[willus]

Originally Posted by Cyga

Hello, anyone know how to change reflow font size on Paperwhite 2?

See the k2pdfopt help page on increasing magnification.

[RTL]

Dear willus,

It is a great idea and tool. Thanks for your work. It helped me a lot.

I have an important, huge, scanned pdf book, and I could not obtain optimal result converting it. I downloaded the source code and skimmed through some parts of it. I have a desire to improve some parts of the code to obtain optimal results converting that book. Can you answer some of my questions? Thanks.

[tigerjack89]

Hi willus, here again.
I was trying to convert a pdf which is composed by two column per page. Which option should I use to have a right pdf?

Also, I was wondering about another option: Native PDF output. Should it be used in order to obtain better results while converting from PDF to EPUB (or some other ebook format)?

Thanks as always for your help and your work.

[willus]

Originally Posted by RTL

Dear willus,

It is a great idea and tool. Thanks for your work. It helped me a lot.

I have an important, huge, scanned pdf book, and I could not obtain optimal result converting it. I downloaded the source code and skimmed through some parts of it. I have a desire to improve some parts of the code to obtain optimal results converting that book. Can you answer some of my questions? Thanks.

Yes--you can PM questions to me if you like, but it may be that there are options that can help you. Can you post or PM me a link to your source PDF?

[willus]

Originally Posted by tigerjack89

Hi willus, here again.
I was trying to convert a pdf which is composed by two column per page. Which option should I use to have a right pdf?

Also, I was wondering about another option: Native PDF output. Should it be used in order to obtain better results while converting from PDF to EPUB (or some other ebook format)?

Thanks as always for your help and your work.

The default mode or the 2-column mode (-mode 2col) should work. Post or PM me a link to the source PDF if you want.

[rebaco]

hi Willus
I do have a PDF (a french novel really rare to find) that I'd like to read on my Kobo h2o
what are the instructions in this case?
thanks

[willus]

Originally Posted by rebaco

hi Willus
I do have a PDF (a french novel really rare to find) that I'd like to read on my Kobo h2o
what are the instructions in this case?
thanks

If the default conversion does not work well for you, then post or PM me a link to a sample of the novel.

[RTL]

Originally Posted by willus

Yes--you can PM questions to me if you like, but it may be that there are options that can help you. Can you post or PM me a link to your source PDF?

Dear Willus,

Thanks for your reply.

Let me describe the book I need to read with the help of k2pdfopt:

(1) It is a big book, around 600 pages, and it is a scanned pdf book.
(2) I need most of the pages, but not all.
(3) It is a secure PDF file, which I can not extract any pages.
(4) It is a bilingual book (source and target translation)
(5) The source text is framed in a solid lined box and it is placed on a quarter of a given page, either on upper left or upper right, depending on the odd and even page number. The target translation text flows around the framed source text.

Now my goal is:

(1) I do not need all of the pages, but most of them.
(2) I do not need the source text, I want to discard it and I only need the target text.

What I have got so far:

As the pages are divided neither left-right nor upper-buttom sections, the k2pdfopt program can not simply extract the target text. For the upper part of the page, there is no reflow, it outputs as it is. For the buttom part (which there is no distraction of framed source text), it can reflow quite well, but not very satisfactorily.

And the marked-up functionality is very good and useful. But I need some interactive functionality, such as human confirmation of using a page or not, and subdividing the page space to pick-up the useful area and discard the useless area, etc. Though it is laborous and time consuming, it is worth the time and effort for some really important and useful books.

[willus]

Originally Posted by RTL

Dear Willus,

Thanks for your reply.

Let me describe the book I need to read with the help of k2pdfopt...

An interesting case, but hopefully there is a reasonable answer. If you can process the book with k2pdfopt then you should be able to extract a few pages with a different tool (e.g. pdfsam or jpdftweak) and PM me a sample. That would be very helpful.

If it's 600 pages you may want to do a chunk at a time--maybe 100-page segments. Or break up by sets of chapters or something. Are you using the MS-Windows version of k2pdfopt? If you put an 'e' in the "pages to convert" box and then click "Margin Select," you'll see all the even pages overlaid. Or you can put in a specific range, e.g. "2-50e" to get pages 2, 4, 6, ..., 50 all overlaid. You can potentially use this in combination with crop boxes (-cbox option) to get what you want. It would help most to have a sample, though, so that I could give you an example that worked on your sample.

[willus]

Originally Posted by RTL

...
(1) It is a big book, around 600 pages, and it is a scanned pdf book.
(2) I need most of the pages, but not all.
(3) It is a secure PDF file, which I can not extract any pages
...

PS. You can even use k2pdfopt to extract sample pages. Set the "Conversion Mode" to "Copy" and then check the "Native PDF output" check box, then put the sample pages you want to extract in the "Pages to Convert" field. Then convert.

[RTL]

Willus,

With your help, now I can extract any pages from the secure pdf file. And the overlapping functionality is useful too. Unfortunately, the cbox option does not work for me, as instead of selecting a region, I need to cut out and discard a region. And another complication is that the book is not produced by computer originally, but with traditional metal typeface publishing method. Thus the page design is not very accurate and the rectangular regions I need to cut-out do not overlay, and each lines do not overlay either. So any batch processing does not work well.

So far, for trial method, I followed the following steps:

(1) With k2pdfopt, I generated a copy of the original secure pdf, getting rid of its security.
(2) With pdfsam, I splitted the book into single pages.
(3) For each single page, I used cbox option to divided a page into 2 pages, namely top page and buttom page.
(4) For the top page, I used again cbox to divided it into left and right portion, discarded the unnecessary part (the boxed original text part)
(5) Before I merge back the top and buttom part, I need to resize the top part's width to the buttom part's width. Otherwise, as portion of the top part was cut out, they have different width and thus reflowing does not work well.
(6) Merged the top and buttom part into a single pdf page.
(7) With pdfsam again, merged all pages into one pdf file.
(8) Used k2pdfopt to reflow.

This is just for around 10-20 pages for trial, as the manual workload is too much.

I attached the overlayed odd and even pages.

[RTL]

As pdf is not easy to be edited, especially the scan generated pdf book, in order to cut the rectangular quadrant out of the page, I used the above manual labor method. Of cource, if I could easily edit scan generated, multipage pdf file, I would never have had to do that way.

When analyzing the working internals of k2pdfopt, I learnt that, with the help of mupdf library, it generates first internally bitmapped images from pdf pages, after processing, reflowing the bitmapped images, it generates back a pdf file.

I need a utility program which can generate multiple bitmap files from a multipage pdf file, and also reverse the process, which generates a multipage pdf file from multiple bitmap files.

What I am thinking about is that, after generating the bitmap files, I can easily edit it and cut out the unnecessary quadrant, then repack it back into a single pdf file. This will save me from the hurdle of editing a scan generated pdf file.

Using the mupdf library, I think it is not very hard to make a utility program with that functionality. Or ot could be added to k2pdfopt as a additional functionality.

Willus, any comment for this?