[GeoffR]

From what I can see there are four different problems that affect KePubs in full-screen mode:


1. If the book's stylesheet has non-zero body margin/padding, then the text is shifted to the right and can be cut off at the right margin.

2. Characters with large side bearing values (such as italic f, J) can be cut off if they appear at either end of a line.

3. Images which are supposed to be displayed inline (flowing with the text) are instead displayed centred in a seperate block.

4. The margin slider stops working after passing an internal html file boundary, closing and re-opening the book will get it working again.


1. and 3. are easily fixed. There is a firmware patch or modification to the book's stylesheet that solves these problems perfectly.

4. I don't know how to fix, but it didn't affect earlier firmware versions so it seems to be something Kobo have introduced, and they should be able to fix it.

2. might be more of a problem, it could be a bug or limitation in the rendering libraries used by the KePub reader, and there might be nothing Kobo can do about it apart from report it to the library developers and wait for them to fix it. There is a firmware patch or modification to the book's stylesheet that works around the problem in most cases, but it is not perfect.

Just speculation, but it could be that Kobo developed the full-screen feature and then during testing found that there was a bug in the third-party rendering libraries that prevented it working properly in KePubs, and are now waiting for the library developers to fix that bug before doing any more work on it. (And it doesn't affect the Adobe ePub reader because it uses different libraries.)

They probably don't want to enable the feature officially for ePubs only, since that would give people one more reason to sideload books instead of syncing them from the Kobo servers.