Idea for book cover screensaver

[JohnsonZA]

I was thinking about how to implement a hack that would set your screensaver to the cover of the current book you are reading. It goes something like this:

1. In a cron script, check the LAST_BOOK_READ variable in the /mnt/us/system/com.amazon.ebook.booklet.reader/reader.pref
2. Extract the book cover from the mobi file from 1
3. Save the cover to /mnt/linkss/screensavers/00001_cover.png
4. ???
5. Profit!

This would obviously rely on the screensaver hack and assumes that the cover image would be the only screensaver image. Saving the file with the same name should remove the need to reboot that the screensaver hack has. The frequency of the cron script could be say 5 minutes. Is there any reason this wouldn't work?

If any experts have an opinion, I'd love to know before wasting my time on any code.

[Rinzwind]

"Saving the file with the same name should remove the need to reboot that the screensaver hack has."

Unless the image is cached

[isotherm]

I think the screensaver image is cached. Also, it would be hard to extract the image from the mobi file if it has DRM. And it would need a different mechanism for Topaz books.

I had an idea earlier that went something like this:
1. Disable display of the normal screensaver images, but leave other power saving functionality in place.
2. The framework has events for screensaver time lapse. Wait for one of these events.
3. At the event, send keys to go to the cover of the book (Menu, Go To..., cover)
4. On resume, send the Back key to return to the user's reading location.

The trouble is that it looks bad (you briefly see the effect of the keys being simulated), and you would have to be very careful that the user is actually reading a book, or otherwise you will send random keys with undefined consequences.

[JohnsonZA]

Originally Posted by isotherm

I think the screensaver image is cached. Also, it would be hard to extract the image from the mobi file if it has DRM. And it would need a different mechanism for Topaz books.

Okay, the screensaver image is cached unfortunately, but the cache is refreshed every time the Kindle wakes up. So after the screensaver image is replaced the cached image is shown the first time the Kindle sleeps. But, after waking and sleeping again, the new image is shown.

Regarding DRM, the headers and metadata aren't encrypted as far as I know. Only the text and images. I haven't actually checked to see if the cover image is encrypted.

I guess this would only work for mobi files initially, but as light is shed on topaz, maybe it can be expanded to work for those files too.