Android PDF application with contrast adjustment feature

chromeuser · 04-23-2016, 11:37 AM

Hello Everyone

,

I use the Icarus Illumina 8 XL and wish to use an external Android application for PDF files (the pinch and zoom doesn't work with the stock application). Unfortunately, near all Android applications don't have a function to increase PDF contrast, which is a must for an e-ink display. Would anyone know of a good PDF application with this feature?

Thanks!

Germanc · 05-05-2016, 09:59 PM

Hi! The best idea is to use the android version of koreader, which is a pdf/mobi/epub reader designed for e-ink. If you want a more classic approach ebookdroid (available on the play store) has an option for contrast and works really well on eink deviced (also the open source version Document Viewer, which is based on ebookdroid and available on f-droid)

chromeuser · 05-09-2016, 10:36 AM

Thanks a lot for the feedback!

I knew about KOReader before but it doesn't work well with Boyue devices (the Icarus Illumina XL 8 is a re-branded Boyue device), as it crashes and barely works.

I found ebookdroid recently and you are right, it offers nice picture enhancement features. The only problem with ebookdroid is the interface, which is confusing - simple features, e.g. highlight and annotation, require some time to get used to.

On Google Play there are a few PDF readers based on ebookdroid, as you noted, but oddly many seem to strip down the features that make ebookdroid a good PDF application (Document Viewer is an example).

Hopefully Moon+ Reader or Bookari will offer a contrast adjustment feature and a more e-ink friendly interface option, as they are, in my opinion, the best e-reader applications.

Germanc · 05-13-2016, 02:44 PM

KOreader can be modified to make it work on boyue devices (I did it to make it work on my Onyx reader). Here is the bug report I did about that: https://github.com/koreader/koreader/issues/1534.
You have to create a file called patch.lua into the folder koreader on your main memory. Inside put:

require("jit.opt").start("sizemcode=64","maxmcode= 512", "recunroll=8", "callunroll=12", "loopunroll=60", "instunroll=16", "tryside=16", "hotexit=160", "hotloop=1792", "maxsnap=160000", "maxside=32000", "maxirconst=160000", "maxrecord=1280000", "maxtrace=320000")
local screen = require("android").screen
screen.height = screen.height + 80
for i=1,1000 do end -- Force allocation of one large segment

Not sure if you need the screen.height line for a boyue device, that's to resize the size of koreader in case it doesn't detect the right screen resolution. I found the patch on a chinese forum and for the bug reports on koreader github this also works for boyue devices. With this it might crash the first time you open it but then it should be pretty stable. How good is Moon+ Reader on eink devices right now for pdf ? I read a lot about that one but never tried it. Is there a crop margin option ?

chromeuser · 05-18-2016, 02:21 PM

Thanks again for the feedback

I prefer to stick to Ebookdroid, as the pinch to zoom works well. However, I might try that KOReader patch.

Regarding Moon+ Pro, I couldn't find cropping for PDF files. However, with pinch to zoom I don't think you need it. You can zoom to the exact size you want. The only issue is contrast enhancement - with E-Ink it is necessary, as the text appears pale and difficult to read. Another nice option, would be the interface and menus being optimized for E-Ink; however, the current interface is legible.

chromeuser · 06-12-2016, 06:35 PM

Thanks for the KOReader tip.

I tried the patch you noted but it didn't work - I still got crashes. Also, even when full screen is set, in user settings, there is always a black strip at the bottom. From the code you shared, there is also a patch to go full screen but it didn't work. I tried KOReader with my Fire HD8 and it is stable, with no problems. Do you think it'll make a difference if I installed Google Play on the Icarus Illumina XL? Or is this a unresolvable problem with Boyue devices?

Thanks again.

Germanc · 06-17-2016, 05:16 PM

For the black strip you can change the +80 for whatever extra size the screen has (just try a few values). But if it still crashes then you are out of luck, sorry !. Koreader doesn't know if Google Play is installed so that won't help.
I think the developers are working on better android support for the next release so it might be a good idea to report a bug to https://github.com/koreader/koreader/issues, at least let them know that it won't work on that device (and maybe adding a logcat too).
Good luck with that !

04-23-2016, 11:37 AM	#1
chromeuser Member Posts: 21 Karma: 10 Join Date: Apr 2016 Device: Samsung Tab A 10.1, Fire HD8, Kindle Paperwhite, Kobo Aura One	Android PDF application with contrast adjustment feature Hello Everyone , I use the Icarus Illumina 8 XL and wish to use an external Android application for PDF files (the pinch and zoom doesn't work with the stock application). Unfortunately, near all Android applications don't have a function to increase PDF contrast, which is a must for an e-ink display. Would anyone know of a good PDF application with this feature? Thanks!

05-09-2016, 10:36 AM	#3
chromeuser Member Posts: 21 Karma: 10 Join Date: Apr 2016 Device: Samsung Tab A 10.1, Fire HD8, Kindle Paperwhite, Kobo Aura One	Thanks a lot for the feedback! I knew about KOReader before but it doesn't work well with Boyue devices (the Icarus Illumina XL 8 is a re-branded Boyue device), as it crashes and barely works. I found ebookdroid recently and you are right, it offers nice picture enhancement features. The only problem with ebookdroid is the interface, which is confusing - simple features, e.g. highlight and annotation, require some time to get used to. On Google Play there are a few PDF readers based on ebookdroid, as you noted, but oddly many seem to strip down the features that make ebookdroid a good PDF application (Document Viewer is an example). Hopefully Moon+ Reader or Bookari will offer a contrast adjustment feature and a more e-ink friendly interface option, as they are, in my opinion, the best e-reader applications. Last edited by chromeuser; 05-09-2016 at 10:38 AM.

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05-05-2016, 09:59 PM	#2
Germanc Member Posts: 23 Karma: 68 Join Date: Oct 2011 Device: Kindle Keyboard	Hi! The best idea is to use the android version of koreader, which is a pdf/mobi/epub reader designed for e-ink. If you want a more classic approach ebookdroid (available on the play store) has an option for contrast and works really well on eink deviced (also the open source version Document Viewer, which is based on ebookdroid and available on f-droid)

05-13-2016, 02:44 PM	#4
Germanc Member Posts: 23 Karma: 68 Join Date: Oct 2011 Device: Kindle Keyboard	KOreader can be modified to make it work on boyue devices (I did it to make it work on my Onyx reader). Here is the bug report I did about that: https://github.com/koreader/koreader/issues/1534. You have to create a file called patch.lua into the folder koreader on your main memory. Inside put: require("jit.opt").start("sizemcode=64","maxmcode= 512", "recunroll=8", "callunroll=12", "loopunroll=60", "instunroll=16", "tryside=16", "hotexit=160", "hotloop=1792", "maxsnap=160000", "maxside=32000", "maxirconst=160000", "maxrecord=1280000", "maxtrace=320000") local screen = require("android").screen screen.height = screen.height + 80 for i=1,1000 do end -- Force allocation of one large segment Not sure if you need the screen.height line for a boyue device, that's to resize the size of koreader in case it doesn't detect the right screen resolution. I found the patch on a chinese forum and for the bug reports on koreader github this also works for boyue devices. With this it might crash the first time you open it but then it should be pretty stable. How good is Moon+ Reader on eink devices right now for pdf ? I read a lot about that one but never tried it. Is there a crop margin option ?

05-18-2016, 02:21 PM	#5
chromeuser Member Posts: 21 Karma: 10 Join Date: Apr 2016 Device: Samsung Tab A 10.1, Fire HD8, Kindle Paperwhite, Kobo Aura One	Thanks again for the feedback I prefer to stick to Ebookdroid, as the pinch to zoom works well. However, I might try that KOReader patch. Regarding Moon+ Pro, I couldn't find cropping for PDF files. However, with pinch to zoom I don't think you need it. You can zoom to the exact size you want. The only issue is contrast enhancement - with E-Ink it is necessary, as the text appears pale and difficult to read. Another nice option, would be the interface and menus being optimized for E-Ink; however, the current interface is legible.

06-12-2016, 06:35 PM	#6
chromeuser Member Posts: 21 Karma: 10 Join Date: Apr 2016 Device: Samsung Tab A 10.1, Fire HD8, Kindle Paperwhite, Kobo Aura One	Thanks for the KOReader tip. I tried the patch you noted but it didn't work - I still got crashes. Also, even when full screen is set, in user settings, there is always a black strip at the bottom. From the code you shared, there is also a patch to go full screen but it didn't work. I tried KOReader with my Fire HD8 and it is stable, with no problems. Do you think it'll make a difference if I installed Google Play on the Icarus Illumina XL? Or is this a unresolvable problem with Boyue devices? Thanks again.

06-17-2016, 05:16 PM	#7
Germanc Member Posts: 23 Karma: 68 Join Date: Oct 2011 Device: Kindle Keyboard	For the black strip you can change the +80 for whatever extra size the screen has (just try a few values). But if it still crashes then you are out of luck, sorry !. Koreader doesn't know if Google Play is installed so that won't help. I think the developers are working on better android support for the next release so it might be a good idea to report a bug to https://github.com/koreader/koreader/issues, at least let them know that it won't work on that device (and maybe adding a logcat too). Good luck with that !

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