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Old 11-03-2012, 08:44 PM   #91
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@Leir: The only way I can reproduce this is if one of the files in the rotation is broken/in the wrong format. It seems to screw up for good (even if the next file is okay) until the next reboot/framework restart.

So, yeah, how many custom screensavers do you have? And check that they're all proper PNG files. (A jpg renamed as a .png is a good way to trigger this kind of thing, for example ).
Yep. It seems to crash until i reset my kindle, and I did download several jpegs and merely renamed them with .png haha! I guess I'll give up using custom screensavers, and great work implementing the cover page as the screensaver!
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Old 11-03-2012, 08:52 PM   #92
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Can we place both the python and the linkss installation files at once and update them together? Just asking on behalf of other lazy people, I'm installing python first by the way.

edit: How do you go about creating a "blank file"? Can't find any tutorials on youtube. What format must the file type be in?

double edit: I simply copied the autoreboot file and named it cover.

Last edited by Leir; 11-03-2012 at 09:14 PM.
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Old 11-03-2012, 09:41 PM   #93
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@Leir:

* I could technically implement another pass that checks & convert/resize the files on the go (instead of just dumping them in the discarded folder) since that's essentially what part of the cover mode is doing, but with a full directory of screensavers, it would take a tremendous amount of time (minutes, probably) for a job that's ultimately better suited to the user on their shiny and powerful computer .

* Nope, one .bin at a time. (And, yep, python first is the way to go ).

* Yep, copying one of the other files there is a good way to do that on Windows.


Speaking of the cover mode, I'd like some feedback on how people think the covers look in the screensaver. I went the same way as the reader (meaning full screen, high quality scaling algorithm, aspect ratio intact, on a white background), but I had to play around with the gamma (after converting the files to grayscale to keep the filesizes down). So if you feel like the covers are too dark/light, I'd like to hear about it .
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Old 11-03-2012, 11:26 PM   #94
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@Leir:

* I could technically implement another pass that checks & convert/resize the files on the go (instead of just dumping them in the discarded folder) since that's essentially what part of the cover mode is doing, but with a full directory of screensavers, it would take a tremendous amount of time (minutes, probably) for a job that's ultimately better suited to the user on their shiny and powerful computer .

* Nope, one .bin at a time. (And, yep, python first is the way to go ).

* Yep, copying one of the other files there is a good way to do that on Windows.


Speaking of the cover mode, I'd like some feedback on how people think the covers look in the screensaver. I went the same way as the reader (meaning full screen, high quality scaling algorithm, aspect ratio intact, on a white background), but I had to play around with the gamma (after converting the files to grayscale to keep the filesizes down). So if you feel like the covers are too dark/light, I'd like to hear about it .
@NiJuLe

I'm extremely pleased with the cover mode, thank you very much for this!
I'm reading Eragon now, and the cover shows up as promised. However, due to its original resolution at 332x500, it does not cover the whole screen of my kindle paperwhite, leaving 2 white bars at the side. It cannot be helped I supposed. I think, not really sure, that the cover has been resized so it looks a little blurry. I would have preferred it to look sharper and more vibrant, but am still overall happy with this hack!
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Old 11-04-2012, 01:45 AM   #95
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Quote:
Originally Posted by NiLuJe View Post
Speaking of the cover mode, I'd like some feedback on how people think the covers look in the screensaver. I went the same way as the reader (meaning full screen, high quality scaling algorithm, aspect ratio intact, on a white background), but I had to play around with the gamma (after converting the files to grayscale to keep the filesizes down). So if you feel like the covers are too dark/light, I'd like to hear about it .
Ah, you got it working! I'm probably way more excited than I should be. Thanks so much for sharing!

The gamma looks good to me, and appears to be quite close to the cover in-book.

If, in theory, I wanted the screensaver to not stick to the aspect ratio, but rather fit to screen... is there anything I could change somewhat easily, or is this strictly do not touch or end up with a big fiery ball visible from space territory?
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Old 11-04-2012, 06:56 AM   #96
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@Leir: Yep, perfectly normal, especially on the PW. 332x500 to 758x1024 is a somewhat severe upscaling, and while the upscaling algorithm is good, it's still an image upscaling algorithm, so a bit of blurriness is to be expected (we're not in CSI, where pixels magically appear from outer space when zooming ^^). And the two white bars on the side are an artifact of keeping the aspect ratio . That said, it should more or less look the same as the 'Go To > Cover' in the reader .

@7hir7een: To be perfectly honest, I kept the aspect ratio intact partly because that's what the reader does, but mostly because I abhor looking at stuff that doesn't respect AR .

That said, it's pretty trivial to change:

In linkss/bin/cover-extract, line 82:

Change
Code:
${LINKSS_BINDIR}/convert "${file}" -resize ${MY_SCREEN_SIZE} -background white -compose Copy -gravity center -extent ${MY_SCREEN_SIZE} -colorspace Gray -gamma 2.2 -quality 79 "${LINKSS_BASEDIR}/cover_cache/cover_${file_key}.png"
To
Code:
${LINKSS_BINDIR}/convert "${file}" -resize "${MY_SCREEN_SIZE}!" -colorspace Gray -gamma 2.2 -quality 79 "${LINKSS_BASEDIR}/cover_cache/cover_${file_key}.png"
(It's a shell script, so the usual warnings apply: don't touch anything else, use a real text/code editor that honors *nix line endings & doesn't decide to put an UTF-8 BOM, etc ).

Last edited by NiLuJe; 11-04-2012 at 10:57 AM.
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Old 11-04-2012, 10:29 AM   #97
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@NiLuJe

Works like a charm! Thank you, kind sir
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Old 11-04-2012, 01:24 PM   #98
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... while the upscaling algorithm is good, it's still an image upscaling algorithm, so a bit of blurriness is to be expected (we're not in CSI, where pixels magically appear from outer space when zooming ^^). ...
Actually, there are some "super-resolution" algorithms that do an excellent job of upscaling WITHOUT "blurriness". Although they cannot create missing detail when upscaling, they do an excellent job of creating "natural looking" (false) details. The simplest method is interpolating only in the direction of least-gradient. This is similar to converting from raster to vector and rendering the upscaled vector image. The more complex (but more natural looking at high magnification) is "fractal scaling". The "least-gradient" upscaling is more suitable to a kindle -- it is commonly used in digital cameras as part of the "demosaicing" process.

Of course, for criminal forensics investigations, that natural looking (but false) detail would not hold up in court. But it COULD make a book cover look "prettier" when upscaling.

EDIT: When it comes to Hollywood "technology", a nice companion to "infinite zoom" is "uncrop", as shown here:

Last edited by geekmaster; 11-04-2012 at 01:45 PM.
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Old 11-04-2012, 11:29 PM   #99
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Umm... I noticed that when using the cover-as-screensaver hack, the screensaver will only display the first book in the collection. For example, I placed all 4 books of the Eragon series in a collection, and when I'm reading eldest (2nd book in the series), the screensaver still shows up as Eragon.
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Old 11-05-2012, 06:57 AM   #100
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@Leir: How did you switch to the next book (Home, then collection, then book, or back, collection, book?).

Also, could you post the file the ;dm command (in the searchbar, on the home page) produce (in the documents folder, IIRC)?

@geekmaster: While it's a nice info, keep in mind that I'm using ImageMagick, and that it's done on device, and it already takes ~10s to process everything (colorspace switch, gamma correct, Lanczos/Mitchell rescale & PNG encoding) .

Last edited by NiLuJe; 11-05-2012 at 11:34 AM.
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Old 11-05-2012, 11:56 AM   #101
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Quote:
Originally Posted by NiLuJe View Post
@Leir: How did you switch to the next book (Home, then collection, then book, or back, collection, book?).

Also, could you post the file the ;dm command (in the searchbar, on the home page) produce (in the documents folder, IIRC)?

@geekmaster: While it's a nice info, keep in mind that I'm using ImageMagick, and that it's done on device, and it already takes ~10s to process everything (colorspace switch, gamma correct, Lanczos/Mitchell rescale & PNG encoding) .
It could be made a LOT faster by pipelining all the operations to be performed at once, but that requires a lot of work recoding it. Also, if a pleasant (but lossy) image is good enough, there are shortcuts that can be taken in the algorithms too. Doing "minimal-gradient super-res" could actually be a lot FASTER than Lanczos/Mitchell, for example. But you have to write your own code if you want it fast with low overhead...

Of course, I would cache the upscaled images so you only need to burn that "10 seconds" once for each book, and I would try to preprocess the images in the background ahead of time if possible, so you would not even notice it...

EDIT: It all boils down to where you want to invest your time, and just how good is "good enough" (both in execution speed and upscaled image quality).

Last edited by geekmaster; 11-05-2012 at 12:01 PM.
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Old 11-05-2012, 12:30 PM   #102
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@geekmaster: Yep, I'm already doing it ASAP (~2s after opening a book), low priority (nice 15), and the processed covers are of course cached .

On the superres front, I'm only vaguely familiar with those from the few similar things used in some SNES/PSX emulators. I was under the impression that they could only do 'fixed' rescaling (ie. 2x, 3x, 4x, etc.) which would be completely unsuitable here . On a more general note, I'm not a big fan of those on 'real' stuff. It works wonders on pixel-art, but I'm really not a fan of the 'feel' it gives to photographs or landscapes .
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Old 11-05-2012, 07:21 PM   #103
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@NiLuJe

Thank you so much for this! I've been less than impressed with my Kindle PW in the first place (pink/green blotches across the screen, both in my original and in my first replacement; I'm waiting for replacement #2), but not having my custom screensavers made it doubly tough.

Your little Python script really does the job with Covers. I used to create my own screensaver of the book jacket for each title I was reading and rotate them in -- but this is so much simpler. Thank you again!

Any chance the font hack is on your radar screen? I do miss my Georgia font (don't know why it's included in the Kindle iPhone app, but not in the Kindle itself...)
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Old 11-06-2012, 04:02 AM   #104
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@Leir: How did you switch to the next book (Home, then collection, then book, or back, collection, book?).

Also, could you post the file the ;dm command (in the searchbar, on the home page) produce (in the documents folder, IIRC)?
sorry for the late reply. I switched to the next book by Home>Collection>Book.
Im afraid I dont understand the dm command thingy, how do I go about obtaining it?
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Old 11-06-2012, 06:20 AM   #105
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@Leir: One the home screen, pull up the search bar (magnifier icon), and enter ;dm there. You should end up with an all_logs_<dates>.txt file in the documents folder. Compress & attach it here .
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