How does the kobo calculate book page counts?

[howyoudoin]

I have the H2O, but I assume this applies to any kobo....

How does the kobo calculate the total number of pages in a book (the count that gets displayed at the bottom of every page on the e-reader) for side-loaded kepubs?

Is there a way to control that algorithm in any way?

[pdurrant]

IIRC, it's the way ADE does it, which is based on the size of the XHTML text of the book. Sloppy coding can, therefore, increase the page count without increasing the visible text!

[PeterT]

No... side loaded kepubs don't use the ADE style page count. I'm actually not sure how they do it.

[GERGE]

My sideloaded kepubs use real page numbers. As in how many refleshes it would take to finish the chapter.

[pdurrant]

How interesting. Sorry for giving the wrong info.

[howyoudoin]

Originally Posted by GERGE

My sideloaded kepubs use real page numbers. As in how many refleshes it would take to finish the chapter.

That's if you use the per-chapter setting, isn't it?

The "entire book" setting gives a fixed number of total pages that is unaffected by font/line spacing/margin settings.

[DNSB]

Originally Posted by howyoudoin

That's if you use the per-chapter setting, isn't it?

The "entire book" setting gives a fixed number of total pages that is unaffected by font/line spacing/margin settings.

Which would suggest it is defaulting back to the ADE synthetic page algorithm. If you are interested, the procedure from Adobe's epub best practices guide is:

Synthetic page names

1. When page map is not available in the document, Adobe Digital Editions will synthesize a page-map based on the document content. The approach used is the following:
   
2. Determine a compressed byte length of each resource which is referenced in the spine, subtracting any known encryption overhead (IV size).
   
3. Assume that there is a page for each 1024 bytes in each resource, rounding up to the nearest whole number of pages for each resource.
   
4. To map page breaks into a resource, use the number of pages for the resource as determined in step 2, count the number of Unicode characters in the resource; distribute synthetic page breaks in the resource evenly between the characters by dividing the number of characters by the number of pages; if the number of characters don’t divide evenly among the pages, round the number of characters per page up and let the last “page” contain less characters than the rest.