so tell me

"premultiplied alpha".

what is it, what does it do, what does it look like without, what is it for, how do you do it???

1,745 views 6 replies
Reply #1 Top

There are a few images in SKS that need premultiplied alpha checked to look correct, Typically i use it on navigation arrow backgrounds and loggoff buttons.

 

To find out what it looks like with and without it.. turn it on... and off. :w00t:

 

Not sure specifically how it works but heres some nice techy info :P

 

http://en.wikipedia.org/wiki/User:Lkesteloot/premultiplied_alpha

Reply #2 Top

The math for this operation is easy when the numbers are premultiplied:

R' = RF + (1 − AF)RB
G' = GF + (1 − AF)GB
B' = BF + (1 − AF)BB
A' = AF + (1 − AF)AB

The result is (0.75,0.5,0.5,0.75), which is the result of having each color's contribution to the pixel weighted by its area.

Clears thangs right up...dont it? :(O

Reply #4 Top

The math for this operation is easy when the numbers are premultiplied:

R' = RF + (1 − AF)RB

G' = GF + (1 − AF)GB

B' = BF + (1 − AF)BB

A' = AF + (1 − AF)AB

The result is (0.75,0.5,0.5,0.75), which is the result of having each color's contribution to the pixel weighted by its area.

Clears thangs right up...dont it?

 

well thats why they call you the Brainiac...lol...what the hell is that?:grin:

Reply #5 Top

Quoting Night, reply 3
I was told there would be no math.

 

 

math:sick:   turns around and runs from this thread :rofl:

Reply #6 Top

what the hell is that?
I was told there would be no math.

 

Thats not math Craig...its an alien language...layouts for crop circles start with that. :borg: