set gamma&contrast with fw 4.2 (pb622)

[paolog]

hi there

from release notes:

"SETTINGS:
1. Implemented contrast and gamma correction mechanism in Adobe and DjVu (this setting is brought in global.cfg)."

On pdf books with images or complex layout is better, imho, the normal view of adobeviewer, without reflow.

That has an adverse effect giving small fonts and greyish character.

Adjusting gamma & correction could help improving readibility.

While we wait for an integration in pb menu, anyone tried to do/did a script to modify global.cfg?

I use pieditor by fjodr, but is a little bit annoying.

Paolo

[paolog]

at the end I did a script to modify the gamma settings for Adobe and DjVu viewer, with the use of iv_shtool made by rkomar to have a graphic interface

https://www.mobileread.com/forums/sho...d.php?t=163556

below there is my code; I'm not a programmer so it's quite raw and naive

#!/bin/ash

SH_IVTOOL=/mnt/ext1/system/bin/sh_ivtool.app

STATUS="`cat /mnt/ext1/system/config/global.cfg | grep Gamma`"

ANSWER=`$SH_IVTOOL -q "$STATUS

Change gamma settings for 
Adobe or DjVu reader?"`

if [ $? -eq 0 -a "$ANSWER" == "y" ]; then

	BACKUP=`$SH_IVTOOL -q "Make a backup of global.cfg in the same place?"`
	
	if [ $? -eq 0 -a "$BACKUP" == "y" ]; then
	
	cp /mnt/ext1/system/config/global.cfg /mnt/ext1/system/config/global.cfg.old
	
	fi

		PRG=`$SH_IVTOOL -o Adobe DjVu`

		CHANGE="`echo "$STATUS" | grep "$PRG"`"

		NEW=`$SH_IVTOOL -t "$CHANGE (new x.x)"`


# here would be nice to test that NEW is grather than 0
#if [[ $NEW > 0 ]]; then
#$SH_IVTOOL -s "MAGGIORE DI ZERO"
#fi
	
		if [ $? -eq 0 -a "$PRG" == "Adobe" ]; then
	
		sed -i "s/GammaLevelAdobe=.*/GammaLevelAdobe="$NEW"/" /mnt/ext1/system/config/global.cfg

		fi

		if [ $? -eq 0 -a "$PRG" == "DjVu" ]; then

		sed -i "s/GammaLevelDjVu=.*/GammaLevelDjVu="$NEW"/" /mnt/ext1/system/config/global.cfg	
	
		fi

		$SH_IVTOOL -s "New gamma settings:
`cat /mnt/ext1/system/config/global.cfg | grep Gamma`"

fi

exit

___
edit: note: added bulletproof suggestions ( $? -eq 0 -a ) in the if tests
___

could anyone help me in testing whether $NEW is greather than 0 ?

thanks

paolo

Did you tried

if [ $NEW -gt 0 ]; then

?

Regards
Ronny

[paolog]

hi Ronny

yes, -gt is for integer

PB gamma has 1 decimal allowed (I use 2.6 for istance)

I tried:

[ $NEW -gt 0 ]
[ $NEW > 0 ]
[[ $NEW -gt 0 ]]
[[ $NEW > 0 ]]
then any kind of combination of quotation of the terms of comparison

Is it always with one decimal?

What is the whole range of this parameter? Maybe it is enough to test $new == "0.0"

Regards

[paolog]

boh?

I tried to catch the difference between 2.999 and 2.9, for istance, but is very hard

anyway Adobe reader doesn't refuse to work with 2.999

Maybe you can test "$NEW" == "0.0" and "$NEW" == "-"* (if NEW runs below 0)?

[paolog]

even $NEW == "0.0" doesn't work
nor "" == ""

[paolog]

sorry [ $NEW == "0.0" ]

works (but they're treated as string here, right?)

negative digits are accepted by the reader, doesn't look very well but works, so I'll allow negative numbers for special situations where it could be handy

that said I think is useless this check

thank you very much Ronny!

Originally Posted by paolog

works (but they're treated as string here, right?)

Yes, but shell variables are always saved as string.

Regards

[rkomar]

Originally Posted by SIRSteiner

Yes, but shell variables are always saved as string.

Regards

In this case they are. The sh_ivtool.app program is outputting string data to stdout.

Besides, numbers are only allowed to be integers in shell scripts, so trying to assign a floating point number like 2.9 to an integer wouldn't have worked right anyway. You should either handle the mantissa and the fractional parts separately, or use something like awk to deal with floating point numbers.

paolog, to make your code more bulletproof, you should be testing the return code of sh_ivtool.app before using the output. It's possible that someone can just hit the escape button in the middle of the dialog and it won't be outputting any proper string. So, as in the README.txt file:

NUM=`sh_ivtool -n "Enter a number:"`
if [ $? -eq 0 ]; then
  if [ "$NUM" > "0" ]; then
    echo It's bigger than 0!
  fi
fi

or, more concisely:

NUM=`sh_ivtool -n "Enter a number:"`
if [ $? -eq 0 -a "$NUM" > "0" ]; then
  echo It's bigger than 0!
fi

[paolog]

hi rkomar!

I'm absolutely un-aware as programmer
I'll amend the script


edit done!
btw, what happens if $? isn't zero?

[rkomar]

Originally Posted by paolog

btw, what happens if $? isn't zero?

It usually means that someone canceled the action (with escape button or otherwise). It can also mean that the wrong arguments were passed to sh_ivtool.app in the first place. I think I just return -1 whenever a proper response isn't available for any reason. I didn't try to return different codes for different errors.

P.S. shell scripting is not easy when you try to do more complicated things. The limitations can make the code quite complex. So, don't feel bad; your code is quite alright.

[paolog]

thanks rkomar
I'm very happy with my script now!
I've a lot of pdf that now I can enjoy!

anyway, for anyone that could be interested attached there is the last script, with the use of function() too! wow!



paolo