How to convert a double to a color in a scale

Question

1.00/5 (1 vote)

See more:

I have an double array whose values are between -0.001 to 0.002. I want to convert the each value to a pixel of color in a two-color scale. -0.001 assign to blue and 0.002 assigns to red. values in between are blends.

Is it possible to do it?

Posted 11-Jan-15 0:44am

Member 11360950

Add a Solution

2 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

OriginalGriff · Accepted Answer · 2015-01-11T00:55:00

Yes.
Just decide how many "shades" you are going to do and map the minimum to RGB Blue, and maximum to RGB red: the intermediate values decrease blue and increase red, either together or one then the other.

It sounds like a poor colour mapping scheme though: what happens when you introduce Green?

**Zoltán Zörgő** · Accepted Answer · 2015-01-11T01:28:00

See here for one way of gradient calculation: http://ionicsolutions.net/2011/12/28/multicolor-gradients-an-introduction-to-working-with-palette-effects/[^]

However you can use WPF's gradient brush logic (even in Windows Forms) to do the same a little bit neater: https://dotupdate.wordpress.com/2008/01/28/find-the-color-of-a-point-in-a-lineargradientbrush/[^]. In your case you have a rectangle of 1px hight.

But there are even more gradient interpolation methods, if you want heatmap for example.

However, you still need to map upper and lower bound to the edges of the gradient and the interim value to a position in the gradient. But that's elementary math.

How to convert a double to a color in a scale

2 solutions

Solution 1

Solution 2

Add your solution here

Preview 0