Solved

Calculating RGBA given different RGB colours.

Posted on 2010-08-26
4
231 Views
Last Modified: 2012-05-10
Hello,

I have three RGB colours, background, foreground and target. The target colour is always between the background and foreground colours. Now, given these three RGB colours, I want to find out what the alpha channel of the foreground colour should be to give the closest approximation of the target colour that only had the RGB channels.

Any ideas on where I can even start this thing???

Thanks,
Uni
0
Comment
Question by:Unimatrix_001
  • 3
4 Comments
 
LVL 84

Accepted Solution

by:
ozo earned 500 total points
ID: 33532897
depending n how you define closest, it may be
(rt+gt+bt)-(rb+gb+bb)/((rf+gf+bf)-(rb+gb+bb))
or
((rt-rb)/(rf-rb)+(gt-gb)/(gf-gb)+(bt-bb)/(bf-bb))/3
perhaps with gamma or other correction
0
 
LVL 3

Author Comment

by:Unimatrix_001
ID: 33533637
Hi ozo,

Very sorry for not getting back sooner, thanks very much - I'll give them a go this evening and let you know how things are.

Thanks again,
Uni
0
 
LVL 3

Author Comment

by:Unimatrix_001
ID: 33534928
Very well done ozo... I really am jealous how you seems to just know how to solve any maths issue... :(
0
 
LVL 3

Author Closing Comment

by:Unimatrix_001
ID: 33534929
Brilliant!
0

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Simple Random Sample 2 55
Logarithms 2 60
Simplify expression 3 87
Word Problem 4 76
How to Win a Jar of Candy Corn: A Scientific Approach! I love mathematics. If you love mathematics also, you may enjoy this tip on how to use math to win your own jar of candy corn and to impress your friends. As I said, I love math, but I gu…
Foreword (May 2015) This web page has appeared at Google.  It's definitely worth considering! https://www.google.com/about/careers/students/guide-to-technical-development.html How to Know You are Making a Difference at EE In August, 2013, one …
This Micro Tutorial hows how you can integrate  Mac OSX to a Windows Active Directory Domain. Apple has made it easy to allow users to bind their macs to a windows domain with relative ease. The following video show how to bind OSX Mavericks to …
This is a video describing the growing solar energy use in Utah. This is a topic that greatly interests me and so I decided to produce a video about it.

863 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

20 Experts available now in Live!

Get 1:1 Help Now