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Am 18.07.2010 13:42, Vinay Pawar wrote:
> Hi,
>
> Using awesome-3.4.6, with libpng-1.2.42 and ImageMagick-6.5.6
>
> Following is a little patch that fixes the error(ignorable) i get at build
> time.
>
> '-gamma 0.6' was added for old ImageMagick compatibility but appears to be
> interfering with the new versions. Also newer ImageMagick-6.5.5 onwards
> there's a new -auto-gamma which could be used in the future.
>
> The 'incorrect gamma=(0/100000)' error is returned by libpng, use 'display
> -verbose <bad-generated-png>' to check sanity of image.
>
> 'convert -gamma 0.6 -channel A -evaluate Multiply 0.4 <image> <new-image>'
> 'convert -auto-gamma -channel A -evaluate Multiply 0.4 <image> <new-image>'
> 'convert -channel A -evaluate Multiply 0.4 <image> <new-image>'
>
> All 3 above commands produce the same image visually. Either '-auto-gamma'
> should be used or '-gamma' should be dropped.
Sorry, but the resulting images do look different.
I grabbed the titlebar icons from the default theme, moved them into their own
dir and ran this uglyness:
for img in *png
do
for x in '-gamma 0.6 -channel A -evaluate Multiply 0.4' '-channel A -evaluate
Multiply 0.4' '-auto-gamma -channel A -evaluate Multiply 0.4' '-evaluate Pow 2
-channel A -evaluate Multiply 0.4'
do
convert "$img" $x "$img: $x.png"
done
done
I then viewed the result with 'feh --index .'.
My findings are that especially no gamma option and '-auto-gamma' produce
different images than what got now. This leaves us with '-gamma 0.6' which is
what we are currently using and '-evaluate Pow 2' which was used before, but was
dropped for compatibility with newer ImageMagick.
Cheers,
Uli
- --
- - Buck, when, exactly, did you lose your mind?
- - Three months ago. I woke up one morning married to a pineapple.
An ugly pineapple... But I loved her!
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