Archive for April, 2007

Xorg/Gnome color profiles

3Dade` • 27th Apr 2007 • Italian

I had Ubuntu and OSX in dualboot for a long time. One of the reasons I always loved OSX is the way everything looks so cool. Finally I’ve been able to understand what is (was) the difference. Osx has a superior management of color profiles.
Each video device (both for acquisition or reproduction) has it’s own ICC profile. This means that before any content is displayed, it is modified according to the device profile.. I used the same background image on both OSes and here you can see the difference :

Ubuntu/Gnome

Mac OSX

So I surfed the web to find about ICC support on xorg. The only tool I found is called “xicc” by Ross Burton: he made a spec and modified eog (eye of gnome) to use the profile loaded by xicc. I tried to load the “Color LCD.icc” I took from osx :) .. and guess what ?

Here you can see the image in the background “badly” displayed by default, and the corrected one (inside eog).. colors are just like in OSX.
Sadly at the moment the only app that supports the xicc spec is eog..

so I adopted a quick trick. Ross told me that the profile provided by apple should be only a gamma ramp correction and I could achieve the same result using “xgamma”, setting the same gamma values that the profile modifies. I was not able to find a tool to extrac RGB gamma values from ICC profile, but I did some guesswork.. and came up with this :

xgamma -rgamma 0.7 -ggamma 0.67 -bgamma 0.6

I suggest to try these settings for everyone that’s using an Apple LCD. The result is pretty cool, it gives more contrast, more color saturation.
And if you don’t like it you can revert to default typing :

xgamma -gamma 1.0

I hope that Xorg and Gnome will have xicc full support soon. In the meantime I’m quite happy with this trick.

Macbook sleeps with Ubuntu !!

2Dade` • 24th Apr 2007 • Italian

I don’t know if they had sex but..

I recently installed Ubuntu Feisty and I was disappointed ’cause sleep wasn’t working. So I reported the bug on launchpad, then a guy came up with a patch found on some mailing list. I just applied it and now sleep works.

The patch is against libata, and is a quick hack that disables device suspend at all.. There sould be an official fix soon.
If you want to try this one all you have to do is download the kernel source package, apply the patch, and compile the kernel modules (make modules). If you need specific instructions just ask me in a comment.

Keepon

0Dade` • 13th Apr 2007 • Italian

Ecco un robot che tutti vorremmo avere sulla nostra scrivania :

Guardate anche QUESTO dove lo si vede ballare a ritmo di musica.

Ne voglio uno.

Questo signore e’ il tizio che l’ha inventato, per fortuna il figlio e’ piu bello del padre. Invece qua c’e’ la descrizione del progetto. Tra l’altro mi ha incuriosito leggere che gli studi di questo team di ricerca partono dall’osservazione dei modelli comportamentali e di apprendimento visivo dei bambini che sono spiegati sul sito, e questi modelli vengono imitati dai loro robot..

Fatemi sapere quando ne posso comprare uno su ebay :)

Tree

0Dade` • 8th Apr 2007 • Italian