-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 Am 18.07.2010 15:52, Vinay Pawar wrote: > --- On Sun, 7/18/10, Uli Schlachter <[email protected]> wrote: > >> From: Uli Schlachter <[email protected]> >> Subject: Re: awesome-3.4.6 patch: error convert: Ignoring incorrect gAMA >> value >> To: [email protected] >> Cc: [email protected] >> Date: Sunday, July 18, 2010, 6:21 PM >> -----BEGIN PGP SIGNED MESSAGE----- >> Hash: SHA256 >> >> 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 >> > > > You can use 'display -identify -verbose <image-file>' and use it's output for > comparison. I find they produce the same result.
Uhm. no they don't. None of my images from the default theme's close_focus.png produce the same output. They are all different. Pixel data is different, channel statistics are different. (Hm, except of the -gamma 0.6 one, they all have Gamma: 0.45) 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! -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) iQEcBAEBCAAGBQJMQwtjAAoJECLkKOvLj8sGr/EIAIgrWKHTuuO3wbCU33yr3mO1 rq2BwpKKztbuzxQO5h14B/IseMsZanJmN1i7v0H+1OK8u61KedrJEIndiChvQEOD 65jOxPgJSDVWsVE/pNdv6SIO5QSxiXZffqJQ+BkFEzh4WV7gOhi8JA//6IG/5f1f PGAnJ325SV4KCsyGKWeYLXrOdCBWg7l9GBSyUAW1rnARtqFdyUPTW6Oy9TmDphLz 5afQtr/jqVAt5FWgaVLABAts6gcasqtWqWnwIB5eQyUM1kmCk8h8irmyAg3oEQyU Wp9I7orGYK4ljPcG13Q5YmK46aMpp6yx2S02rtDrCBSbzsAzgbcRPw+/VfOh1B8= =ACrb -----END PGP SIGNATURE----- -- To unsubscribe, send mail to [email protected].
