KPV: a PDF reader for Kindle, based on muPDF, GPLv3

[geekmaster]

Originally Posted by aliabbasjp

Sorry for the terse reply . But you should understand that i dont bother about the technical details of how gamma works. I only wanted a solution to darken my text by default.

Ahh... I see... Then this link should provide the answer to all of your questions:

http://mattgemmell.com/2008/12/08/what-have-you-tried/

[hawhill]

I don't see that we would have set an upper limit. In fact, in the "+" direction, the configuration value for "gamma" is increased. Doesn't make much sense, because geekmaster is right about that it should be the other way around. However, I think it might be a case of e-ink speciality that the highest pixel value means the darkest shade of gray.

To put things short: on "vol+" key, gamma is multiplied by 1.25, on "vol-" key it is multiplied by 0.8. So just count "+" presses and then replace the value you have already found in unireader.lua by 1.25^n(presses). Or just try some values without bothering for math.

This operation is done before mapping 8bpp grayscale to 4bpp grayscale, so the effect makes at least some sense.

This could be a configurable global setting in some future version of this software.

[geekmaster]

Originally Posted by hawhill

I don't see that we would have set an upper limit. In fact, in the "+" direction, the configuration value for "gamma" is increased. Doesn't make much sense, because geekmaster is right about that it should be the other way around. However, I think it might be a case of e-ink speciality that the highest pixel value means the darkest shade of gray.

To put things short: on "vol+" key, gamma is multiplied by 1.25, on "vol-" key it is multiplied by 0.8. So just count "+" presses and then replace the value you have already found in unireader.lua by 1.25^n(presses). Or just try some values without bothering for math.

This operation is done before mapping 8bpp grayscale to 4bpp grayscale, so the effect makes at least some sense.

This could be a configurable global setting in some future version of this software.

Doing gamma adjustments on bright areas is a valid operation, and I use it to prevent blooming (wash-outs in bright areas), by inverting an image and doing gamma adjustments on the negative, then inverting it back.

Traditional gamma adjustments primarily affect dark areas though, to compress the large linear brightness range between daytime and night into the fewest bits by exploiting non-linearity in the human eye. When applying an exponential curve to the inverted image, it is technically not "gamma", and this appears to be what you are adjusting because of the inverted color palette (0=white) on the K3 and earlier (and the K4 when booted from the main partition).

In all my new code, I use a non-inverted (0=black) color palette, and for kindles that use an inverted color palette (such as the K3) I use the "inverted update" ioctl() function.

Originally Posted by hawhill

... So just count "+" presses and then replace the value you have already found in unireader.lua by 1.25^n(presses). Or just try some values without bothering for math.

Except our poster probably wants you to change it for him and send the replacement files to him, in a nice and simple update*.bin file, not wanting to be bothered by "technical details" and all...

[geekmaster]

Why are people who get irritated by technical details and general theory and only want an exact answer tailored to their specific case hanging out in a "Developer's Corner" forum anyway?

[hawhill]

yeah, we just pass through muPdf naming decision :-) And we do that before inverting for the e-ink display. But we won't bother to change naming policy on upstream, I think :-)

And well, this is a thread that has become more and more usage related. While I would prefer developer discussion, I can understand that this is a welcome forum to ask for practical usage related questions.

[geekmaster]

Originally Posted by hawhill

And well, this is a thread that has become more and more usage related. While I would prefer developer discussion, I can understand that this is a welcome forum to ask for practical usage related questions.

But if you post in the parent "Amazon Kindle" forum, there are "power hungry" members hanging out there who love to challenge your technical expertise because they interpret some English words differently than you do and will go to great lengths to "prove" that your entire technical argument is faulty based on small details of grammar and word usage. Perhaps it should be made a sibling of the "Kindle Developer's Corner" instead of a parent, and renamed into "Amazon Kindle Pedantic Nit-Pickers Corner". Then you can move the "usage" discussions over there where they can devolve into "English usage" discussions.

[aliabbasjp]

Simplicity is the root of all genius

“Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius — and a lot of courage — to move in the opposite direction.” Albert Einstein

[geekmaster]

Originally Posted by aliabbasjp

Simplicity is the root of all genius

“Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius — and a lot of courage — to move in the opposite direction.” Albert Einstein

If simpler is better, another Albert Einstein quote says the essence of this in fewer and simpler words: https://www.mobileread.com/forums/sho....php?p=2013851

[jacobmars]

There is no way I can press shift+P+D in 0.7 sec. Everytime I input P or D.
Maybe it's my DXG ROM, what should I do? (shift+P+K doesn't work, neither.)

[aliabbasjp]

press shift for a longer time till u align your fingers on P and D. All keys need to be pressed consecutively and not simultaneously

[aliabbasjp]

Originally Posted by geekmaster

If simpler is better, another Albert Einstein quote says the essence of this in fewer and simpler words: https://www.mobileread.com/forums/sho....php?p=2013851

The one which i quoted says much more:

• An Intelligent fool (geeks??) makes simple things complex.
• A genius makes complex things simple and does NOT TRY to complicate simple things.

[jacobmars]

Originally Posted by aliabbasjp

press shift for a longer time till u align your fingers on P and D. All keys need to be pressed consecutively and not simultaneously

still no response.
drive me crazy.

[aliabbasjp]

Is LP installed correctly?
if yes try increasing the values(ms) in launchpad.ini :
InterKeyDelay = 300

[aliabbasjp]

Originally Posted by aliabbasjp

Is LP installed correctly?
if yes try increasing the values(ms) in launchpad.ini :
InterKeyDelay = 300

try increasing the values(ms) in launchpad.ini :
HotInterval = 700

[jacobmars]

Originally Posted by aliabbasjp

try increasing the values(ms) in launchpad.ini :
HotInterval = 700

it works. you're my god.