EQInterface Forums

EQInterface Forums (http://www.eqinterface.com/forums/index.php)
-   Graphics modification help. (http://www.eqinterface.com/forums/forumdisplay.php?f=31)
-   -   Answer: What an Alpha is... (Transparency) (http://www.eqinterface.com/forums/showthread.php?t=4166)

birdboydowns 11-20-2002 02:23 PM

Answer: What an Alpha is... (Transparency)
 
I am just about to start working on skinning, and came here for info. In order to "give back" I am gonna try to explain what Alphas & Masks are. (I work in TV graphics, so I have explained this one countless times):

<This is gonna be real Tech-geekish, but bare with me, it has a point> An image is saved using three different integers: Red, Green Blue. For simplicities sake, I am just gonna work with 16 bit color, so any color you use will actually have 3 values from 0-255(one for each of these three).

For example:
Red is R 255, G 0, B 0
Black is R 0, G 0, B 0

Now, if you have Photoshop, open an image and goto the "Channels" Tab (next to Layers). You will see that there are seperate channels for R, G, and B. Now, click on R (Red). Yyou will see a black&white image. This represents the Red value ONLY. Black equals a value of 0, and white equals a value of 255, and the various shades of gray are every thing inbetween. Nifty, eh?

Now, this is all fine and dandy, but what about if you want transperancy?

Well, that is what an alpha channel is.


An alpha channel is EXACTLY like the red, green and blue channel. black equals completely transparent, white equals completely visible, and the various shades of gray are every thing inbetween.

So, if you want a certain part to be 50% transparency, you should fill it with Pure Grey=127 (256 x 50% = 127)


Now, just play around with it... it is a weird concept, but once you get it, it is VERY simple.



---------------

Well, I hope this makes sense... if it doesnt, sorry but Alpha channels are weird to most people.

Rolleo 11-20-2002 04:00 PM

Quote:
So, if you want a certain part to be 50% transparency, you should fill it with Pure Grey=127 (256 x 50% = 127)


Unfortunetly, this type of transparency (actually should be called translucent cause it's partly visible, partly non visible) isn't supported, which sucks. The images that eq accepts need a single defined Alpha channel for transparency, and only supports ON or OFF levels. You can't have part of the image completely visible, another completely invisible, and another 50% visible.

birdboydowns 11-21-2002 10:33 AM

I was talking about alphas in general, not just for the GUI.

jobeken 11-22-2002 09:07 AM

*sigh* never mind, not getting into this.

Sinian 01-27-2003 03:00 PM

Thanks...
Honestly, I've been guessing about what the Alpha channel is, but now I know. And Knowing is half the battle.

Lilcure 01-27-2003 09:02 PM

Beg to differ :) but the cursor I made has 3 different transparency levels and they all work. Outer part opaque, inner part about 75% visible and a center line totally visible.

Seems to work fine for me.

Rolleo 01-28-2003 03:57 AM

that post is over 2 months old, i've since learned otherwise and have already stated I was wrong in other threads. Thanks, though.

Lilcure 01-28-2003 09:04 AM

Didn't even look at the dates hehe...sorry this wasn't meant as a slam at you in the slightest rolleo :) So many threads on here hard to keep up with them all sometimes.


All times are GMT -5. The time now is 05:45 AM.

vBulletin Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.