Prepagination

[ees]

Hi,

First, thanks for the excellent work on calibre!

I just discovered that news feeds in LRF format seem to reset the Reader (Sony PSR-505). As many have pointed out, two work-arounds are:

1) use EPUB, or
2) use LRF, but transfer the file to the Reader using Sony's software, which performs pre-pagination.

While both approaches have worked, I would really like to use LRF *and* avoid reliance on Sony's software. I prefer LRF because it justifies text, whereas EPUB currently does not. And because I've been blessed/cursed with GNU/Linux, using Sony's software really isn't much of an option for me.

Is there any way to add pre-pagination in calibre for LRF? Do we know how to it (but lack the manpower), or is there a fair amount of reverse-engineering that still needs to be done?

Thanks!

- e

[pilotbob]

Originally Posted by ees

Is there any way to add pre-pagination in calibre for LRF? Do we know how to it (but lack the manpower), or is there a fair amount of reverse-engineering that still needs to be done?

Boy this sholld be in the FAQ if it is not. Kovid has said many times that this is not going to be done by him. Of course, patches are welcome.

BOb

[ees]

Originally Posted by pilotbob

Boy this sholld be in the FAQ if it is not. Kovid has said many times that this is not going to be done by him. Of course, patches are welcome.

BOb

Fair enough! I'll take a peek. Pointers, tips, or en/dis-couragement always appreciated.

- e

[Andurian]

I'm happy the question was asked, because until I read it I didn't know that epub doesn't justify text. I had been using LRF exclusively and hate justification.

Happy me!

[pilotbob]

Originally Posted by ees

Fair enough! I'll take a peek. Pointers, tips, or en/dis-couragement always appreciated.

- e

Sorry. I can't be of much help there. I would say

1. You would need to write it in Python.
2. You would need to determine how this is done by reverse engineering the indexing that the Sony eBook Library or the device itself does. I have no idea where this index is stored.. but possible Kovid or Igor could help you here.

BOb

[kovidgoyal]

The problem is you have to exactly duplicate the rendering algorithm used by SONY's LRF renderer. The LRF viewer in calibre comes close, but not quite. Once you do that, the rest should be easy.

[ees]

Originally Posted by Andurian

I'm happy the question was asked, because until I read it I didn't know that epub doesn't justify text. I had been using LRF exclusively and hate justification.

Happy me!

As an aside, does anyone know whether the lack of justification in EPUB is a limitation in the generated EPUB file or in the device firmware?

- e

[ees]

Originally Posted by kovidgoyal

The problem is you have to exactly duplicate the rendering algorithm used by SONY's LRF renderer. The LRF viewer in calibre comes close, but not quite. Once you do that, the rest should be easy.

Do you mean to suggest that when I use Sony's software to transfer a calibre-generated LRF file, Sony's software 1) reads in calibre's LRF file, 2) re-renders it using Sony's rendering algorithm, and 3) pre-paginates the result?

Thanks,
- e

[kovidgoyal]

Originally Posted by ees

Do you mean to suggest that when I use Sony's software to transfer a calibre-generated LRF file, Sony's software 1) reads in calibre's LRF file, 2) re-renders it using Sony's rendering algorithm, and 3) pre-paginates the result?

Thanks,
- e

Yes, I do

[ees]

Originally Posted by kovidgoyal

The problem is you have to exactly duplicate the rendering algorithm used by SONY's LRF renderer. The LRF viewer in calibre comes close, but not quite. Once you do that, the rest should be easy.

Thanks so much for the insight.

You also seem to suggest that it is important to exactly duplicate Sony's LRF rendering algorithm *before* applying any pre-pagination. Assuming we know what the pre-pagination algorithm alone involves (do we?), what would happen if we simply apply pre-pagination to the calibre's LRF output?

In other words, what do you hypothesize will happen if we skip Sony's LRF re-rendering step?

Is the problem one of reverse-engineering, namely that we don't know what Sony's pagination algorithm involves, and that it's hard to diff calibre's LRF output with Sony's LRF output (with pagination) because there are too many things changing (i.e., Sony's rendering changes, plus pagination changes)?

(Or did I miss a concept?)

Thanks,
- e

[pilotbob]

Originally Posted by ees

In other words, what do you hypothesize will happen if we skip Sony's LRF re-rendering step?

Ok... I'm assuming here... and so is Kovid I expect... that the eBook library renders the LRF file to determine the start and stop position/location of each page in the eBook for each font size. This information is used for navigation on the device when reading the ebook.

My guess would be if you are a bit off... it won't really hurt to much in that the page number may be a bit off. I could be wrong of course.

BOb

[kovidgoyal]

Look at the media.xml file on your device. It contains the prepagination information (hex encoded IIRC). LRF is a (partially) reflowable format. What the pre pagination does is tell the reader how many screens of text are there at a particular font size and where in the file each screen starts and ends. So to duplicate that, you have to layout the text on an in-memory screen exactly as the reader would. If you are a little off, that will result in missing lines of text, as you see when you replace the fonts on the reader with others that have different metrics and then try to use a pre paginated book

[llasram]

Originally Posted by kovidgoyal

Yes, I do

Oh, that's harsh, Kovid .

[kovidgoyal]

Originally Posted by llasram

Oh, that's harsh, Kovid .

I just spent the last hour shoving my wife's car out of a snowed in parking lot. I've had it with snow! Iguess ees nick reminded me of a snowflake or something

[ees]

Originally Posted by kovidgoyal

I just spent the last hour shoving my wife's car out of a snowed in parking lot. I've had it with snow! Iguess ees nick reminded me of a snowflake or something

There's snow in Pasadena? Wow!