k2pdfopt: optimizes PDFs for viewing on e-readers

[nook user]

Originally Posted by willus

Or is it because not all the source pages are in the same rotation orientation and you want to rotate them all to the same orientation?

Tangibly in my case all the source pages are in the same orientation.

Originally Posted by willus

is it because you want to read only certain pages in landscape mode on your reader

Yes

[Psyny]

Hello, can i define the "region order priority"?

I mean, when K2pdfopt is generation, by default, a marked layout that looks like:

---------
| 1 | 2 |
----------
| 3 |
----------

In this case, the second "page" generated will allways be below the first. Something like:


---------
| 1 | 3 |
----------
| 2 |
----------

Sorry if i cant express well my question...

By the way, great work.

[willus]

Originally Posted by Psyny

Hello, can i define the "region order priority"?

I mean, when K2pdfopt is generation, by default, a marked layout that looks like:

---------
| 1 | 2 |
----------
| 3 |
----------

In this case, the second "page" generated will allways be below the first. Something like:


---------
| 1 | 3 |
----------
| 2 |
----------

Sorry if i cant express well my question...

By the way, great work.

It is not clear to me what you are asking. Maybe you can provide an example of a source PDF file along with the converted PDF file and explain how you'd prefer it to look? There are potentially a number of ways to do what you want. See maybe the help page on column order or the -grid or -cbox options on the command-line help page.

[Psyny]

Originally Posted by willus

It is not clear to me what you are asking. Maybe you can provide an example of a source PDF file along with the converted PDF file and explain how you'd prefer it to look? There are potentially a number of ways to do what you want. See maybe the help page on column order or the -grid or -cbox options on the command-line help page.

Thanks for the reply!

Without the GRID option:
Page 1:
In this page, the redbox order should be changed to 1, 3, 2.
Indigo - Ophelia Keys.epub

Page 2:
In this page everything is allright.
Indigo - Ophelia Keys.epub

With the GRID option:
Page 1:
Works great, as expected.
[Image violates guidelines for size - MODERATOR]

Page 2:
The table is divided... as expected too, but out of order and harder to read.
Indigo - Ophelia Keys.epub


The used PDF file is at:
https://www.dropbox.com/s/a5rp5o2cdl...2C107.pdf?dl=0


Any advice?

[willus]

You've done a great job experimenting with the options. I'm impressed. The cropbox option (-cbox) is the most powerful option because you can specify custom individual regions, and they can be page specific. E.g., try this in the "Additional options" box (keeping your other settings--e.g. margins--how they are):

-cbox1 0s,0s,0.5s,1s -cbox1 .5s,0s -cbox2- 0,0

The above options select two crop boxes on page 1 (-cbox1)--the left and right halves of the page. The -cbox2- 0,0 selects the full page for all of the rest of the pages (2 and up).

I realize this is painful because you have to manually do the regions yourself. There's no automatic parsing that works for all of the pages of your particular PDF because the graphic at the bottom of page 1 screws up the column detection, as you've shown.

I may eventually give the -grid option the ability to be page specific.

[Psyny]

Originally Posted by willus

You've done a great job experimenting with the options. I'm impressed. The cropbox option (-cbox) is the most powerful option because you can specify custom individual regions, and they can be page specific. E.g., try this in the "Additional options" box (keeping your other settings--e.g. margins--how they are):

-cbox1 0s,0s,0.5s,1s -cbox1 .5s,0s -cbox2- 0,0

The above options select two crop boxes on page 1 (-cbox1)--the left and right halves of the page. The -cbox2- 0,0 selects the full page for all of the rest of the pages (2 and up).

I realize this is painful because you have to manually do the regions yourself. There's no automatic parsing that works for all of the pages of your particular PDF because the graphic at the bottom of page 1 screws up the column detection, as you've shown.

I may eventually give the -grid option the ability to be page specific.

Thanks. I will try out cbox.

In above case, found out that working with -wt helped a little:
[Image violates guidelines for size - MODERATOR]


One day, a command to let k2pdfopt ignore areas without OCR/Textmarkings when defining coluns would be great.

Something like:
-corc[+] [i|t] <inches>

Where:
<inches> : max ocr/markings distance k2pdfopt will look for another text to define a colum.
+ : allow process of areas without oct/markings
i : to include in the colum the area around markings defined by <inches>
t : to not include in the colum the areas around markings defined by <nches>

I know its too much, just a ideia.

[willus]

Originally Posted by Psyny

One day, a command to let k2pdfopt ignore areas without OCR/Textmarkings when defining coluns would be great.

Something like:
-corc[+] [i|t] <inches>

Where:
<inches> : max ocr/markings distance k2pdfopt will look for another text to define a colum.
+ : allow process of areas without oct/markings
i : to include in the colum the area around markings defined by <inches>
t : to not include in the colum the areas around markings defined by <nches>

I know its too much, just a ideia.

It's not too much--I'm just not sure I understand entirely what you want this option to do, but I get the idea that it involves using the OCR layer to detect the columns. I suppose it would also be nice if I could figure out a way to ignore background graphics. There is probably a way to do that using the MuPDF API that isn't too difficult.

[Psyny]

Originally Posted by willus

It's not too much--I'm just not sure I understand entirely what you want this option to do, but I get the idea that it involves using the OCR layer to detect the columns. I suppose it would also be nice if I could figure out a way to ignore background graphics. There is probably a way to do that using the MuPDF API that isn't too difficult.

Hi Willus, sorry for the delay.

Indeed the idea to use OCR layer to detect columns/regions.
That could help in cases where graphics could mess up region detection.

For sample, this text:



Using the command suggested earlier:
-corc[+] [i|t] <inches>

Where:
<inches> : max ocr/markings distance k2pdfopt will look for another text to define a colum.
+ : allow process of areas without oct/markings
i : to include in the colum the area around markings defined by <inches>
t : to not include in the colum the areas around markings defined by <inches>

k2pdfopt could use OCR layer ( in green ), add an offset of it ( in purple ) to detect columns/regions ( in red ):



The command to this result, based on the sugestion, would be like:
-corc i 1.0

The offset is used to detect near OCR layers, if another OCR layer touch the offset of another OCR layer, its is considered the same column/region.

The "i" parameter would be used to add the offset area to the final region slice.
If we use "t" instead, the offset area is still used to detect nearest areas, but not included in final region. Like: -corc t 1.0



If the offset is increased to the point of crossing another OCR area, the region should be the same, like: -corc i 2.0



This should help better use of regions in files with heavy background usage, but good OCR layers.

Dont know if possible... =P

[GOODMAN]

DEAR WILLUS

I want to learn 2 solutions

1. I want to get more number of rows of text per crop box and less magnification in lanscape mode. So is there any way to control crop box size and what are the commands i have to use?
2 In the grid mode, I want to get cuts with margins intact without having crop boxes applied so that I can get same text size page per page rather than variable text sizes.
Please help me.

GOODMAN.

[Elaxon]

What should the settings be for h20?

[willus]

Originally Posted by Psyny

Hi Willus, sorry for the delay.

Indeed the idea to use OCR layer to detect columns/regions.
That could help in cases where graphics could mess up region detection.
[...]
Dont know if possible... =P

FYI for now you can already get k2pdfopt to crop around the OCR regions:

k2pdfopt -cbox 0x,0x,1x,1x myfile.pdf

Will trim each page exactly around the OCR text. See the -h usage in the command-line options. If you want a little pad around the OCR text:

k2pdfopt -cbox -.05x,-.05x,1.1x,1.1x myfile.pdf

[willus]

Originally Posted by GOODMAN

DEAR WILLUS

I want to learn 2 solutions

1. I want to get more number of rows of text per crop box and less magnification in lanscape mode. So is there any way to control crop box size and what are the commands i have to use?
2 In the grid mode, I want to get cuts with margins intact without having crop boxes applied so that I can get same text size page per page rather than variable text sizes.
Please help me.

GOODMAN.

1. The -odpi option should help with this. Try making it smaller. Or make your device width and height larger. You might also want to put in -fc-. That prevents k2pdfopt from trying to fit regions to the width of your device.

2. If you want each section of the grid to go on its own page, unaltered, use the crop mode:

k2pdfopt -mode crop -grid 2x2 ...

[willus]

Originally Posted by Elaxon

What should the settings be for h20?

k2pdfopt -w 1080p -h 1310p -odpi 265 ...
It will be a selectable device in the next release. Thanks to the users who posted screenshots of Kobo devices in my screenshot thread.

[Psyny]

Originally Posted by willus

FYI for now you can already get k2pdfopt to crop around the OCR regions:

k2pdfopt -cbox 0x,0x,1x,1x myfile.pdf

Will trim each page exactly around the OCR text. See the -h usage in the command-line options. If you want a little pad around the OCR text:

k2pdfopt -cbox -.05x,-.05x,1.1x,1.1x myfile.pdf

Hello Willus,

Tryed this command line (-cbox 0x,0x,1x,1x) in the previous case:
https://www.mobileread.com/forums/sho...&postcount=964

But not used command line... Theres happening something odd.
When i use the preview option to view the page 1, the red areas layout and form is one ( the correct one btw ).
So i change to page 2, preview it, and go back to page 1.
When i go back to preview page 1, red areas are different from the first time.

If i generate the final file before previewing anything the file is one.
If i generate after previewing page 2, the result os another. Same behavior as stated above.

Any idea?

File used:
https://www.dropbox.com/s/a5rp5o2cdl...2C107.pdf?dl=0

[willus]

Originally Posted by Psyny

Hello Willus,

Tryed this command line (-cbox 0x,0x,1x,1x) in the previous case:
https://www.mobileread.com/forums/sho...&postcount=964

But not used command line... Theres happening something odd.
When i use the preview option to view the page 1, the red areas layout and form is one ( the correct one btw ).
So i change to page 2, preview it, and go back to page 1.
When i go back to preview page 1, red areas are different from the first time.

If i generate the final file before previewing anything the file is one.
If i generate after previewing page 2, the result os another. Same behavior as stated above.

Any idea?

File used:
https://www.dropbox.com/s/a5rp5o2cdl...2C107.pdf?dl=0

Very interesting. I was able to reproduce this, so I'll investigate it before the next release and hopefully resolve it. Thank you. I'm not entirely surprised since this is a relatively new feature (the "x" unit was implemented in v2.20) and I didn't do a lot of testing on it.

BTW, your dropbox link no longer works (I had the file already).