GSoC CM collaboration

Tomas Carnecky tom at
Mon Mar 3 11:29:24 PST 2008

Olivier Galibert wrote:
> On Mon, Mar 03, 2008 at 06:59:50PM +0100, Tomas Carnecky wrote:
>> It adds additional costs, that's true, but so does if every toolkit does 
>> the transformation on its own!
> *Way* less in the toolkit, though.  Look at your screen, and think
> about the number of color lookups the toolkit would have to do
> compared to the number of pixels in the window.

Given the fact that the newer gtk engines use OpenGL (don't know about 
Qt), and if they were to implement the conversion they'd be using 
shaders (you don't want to render the UI, copy it to system memory, 
perform the conversion, and copy it back to the video card), then no, it 
would cost about the same on a gnome desktop.

Part of the GSoC project I could do some performance measurement to see 
how much faster the conversion on CPU vs. shaders is, how big the 
difference is on a normal desktop etc.

>> Also, you wouldn't have to run the shader 
>> on every window, maybe only on those that have a profile specified on 
>> their window and by that are showing that they care about the colors.
> Well, if you want to do it on for the windows which care, your job is
> already done.  The applications which do care about CM already manage
> it internally.  No need to add anything else in the server or the

So applications that _do_ care about colors already manage them, so 
really, where's the problem?
... it was my impression that Kai-Uwe wanted to have this color 
management integrated X, in a way so that all applications could profit 
from it. So I'm proposing a solution that is as far down on the stack as 
possible, in a place where all applications would automatically profit 
from it, no matter which toolkit they are using.

> composite manager (which I've yet to see someone keep running after
> the novelty has worn off).

I do. It's just a normal window manager, I'm amazed how many people 
ignore that fact, only look at the various screenshots/videos of people 
showing off and say that it's just a toy. It has some useful plugins, 
and some plugins for people who want to show off, but nobody is forcing 
you to use those. I disabled most of them and only keep those that are 
useful (out of the 72 plugins I have 10 enabled).


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