<ross> :)
<ross> loved the snot
<maria> grim
<ross> i think i'll gimp it tonight
<ross> re the gamma thing, i have a plan of action
<maria> and get rid of the cowsnot?
<ross> yeah
<maria> it's probably for the best
<maria> i mean
<maria> on the high res version you can see all the bits in it
<ross> yeah
<ross> its nastyl
<maria> you're the one that wanted it :P
<ross> i did, i wanted the full details
<ross> so its entirely my own fault
<maria> think yourself lucky
<maria> i took some pics of one of our sales staff a few months ago
<maria> i transferred the JPEGs over and starting browsing the directory with gqview
<maria> except i'd left it set to 1:1 zoom
<maria> so i ended up with a 4 inch tall visage of the nicotine stained teeth of one of the sales staff in the middle of my monitor
<ross> urgh
<ross> i need to put my gamma hat back on, i've forgotten the maths
<ross> if the grid at gamma 1.0 is 50% and 100%/0% 
<maria> you mean the dithered part?
<ross> i'd so some weird logs to 50% to get the values for (say) gamma 2.2
<ross> yes
<ross> i'm writing a widget to display the grid, to save having lots of images
<maria> hmm, ok
<maria> give me a second, i'll give you the maths
<ross> but i might take the images you have to get the colour values right :)
<maria> :)
<maria> there is maths, but i'm on the phone
<maria> ok
<maria> right, here we go
<maria> to get the luminosity value for anything that isn't gamma 1.0 you need to do this
<maria>  $INTENSITY^(1/$GAMMA)
<maria> now, if you're doing this with pixel values you need a scaling factor of 256
<maria> and then subtract 1 because computers start counting from 0
<maria> so
<maria> 50% grey at gamma 2.2 :
<maria> (256*(0.5^(1/2.2)))-1
<maria> which is 186
<maria> with me?
<ross> yeah
<maria> 50% grey at 1.8:
<maria> (256*(0.5^(1/1.8)))-1
<maria> 173
<ross> cool
<maria> remember to user floating point with at least 5 sig figs, and then round to the nearest integer
<ross> i'll just do the lot in doubles to be safe
<maria> it's quite nasty because you're losing colour detail when scaling to a none flat gamma
<maria> but on the other hand, monitors have the widest colour gamut between 2.2 and 2.5
<maria> which is why people want us to use 2.2
<maria> also, you'll need something to help people calibrate their blackpoint
<ross> yeah, that is the other plan
<ross> a photoshop calibrate clone would have gamma, blackpoint and colour balance
<ross> (temperature)
<maria> you can't alter colour balance
<maria> leave the user to do that on the monitor
<maria> to calibrate blackpoint though, all you need is a few squares
<ross> i think i can manipulate the X server to adjust the eventual temperature
<maria> if you want to go overboard you can have squares at 0.6% 0.8% 1% 1.2% 1.4% and 1.6%
<maria> people should calibrate the blackpoint so that they can distinguish between black and 1% but not black and 0.8%
<maria> since 1% is about the threshold of human sight
<ross> bbiab, admin stuff to do
<maria> though nowadays you might want to have that at 0.6%
<ross> but you will soon use gnome-gamma-control
* maria notes that her gamma is controlled already without the use of that :)
<maria> btw, i think you need all three decimals of accuracy
<ross> righto
<maria> and some form of fine-tuning sliders
<ross> i did allow the window to be resized :)
<maria> heh
<maria> but that's still not quite accurate enough
<ross> i'll add a text box
<maria> that will be useful, but i think you still need the fine tuning sliders
<ross> what do you mean?
<ross> a button to move by 0.01?
<maria> a small set of sliders, optionally displayed, that can add up to +/-0.015
<ross> right
<ross> i'll see what i can do
<maria> so you can have much finer control over the gamma
<maria> oh
<maria> and leave the main control active when you're in the advanced section
<maria> but arrange it so that moving the main control moves all the colour controls by the same amount, but doesn't lock them to the same value
<ross> aah
<ross> thats a plan
<ross> i was wondering over that for ages
<ross> tricky though
<ross> but i may just be able to do it
<maria> it's a million to one shot
<maria> but it might just work
