Is there any tool to draw dimensions for the distance between colours?

[EllyYi]

I'd like to know if there's any tool to draw dimension for the distance between colours.

Like I put a picture of rainbow and the tool can measure the dimension between the colours.

The rainbow size can be differ from pictures.

T.I.A.

[erinferinferinf]

I moved your thread to the Exchange area thinking that it was a request for a third party tool, like a plugin or extension...

But now that I read this more closely, what application are you using? Photoshop? Illustrator? Dimension?

Are you trying to measure the stripes of a rainbow, or measure color temperature, or distance in pixels...?

[EllyYi]

I'm sorry I missed to mention the application. It's photoshop.

I want to measure the distance between colours so it should be the distance in pixels.