color wheel picker

[Andrew Poulos]

I need to build a colour wheel. It has these specs:
- The user needs to be able to select a colour from it
- It should show as many colours as reasonable. The client wanted the
entire 16 million+ colour spectrum but I pointed out that at one colour
per pixel that's a 2,000 pixel square. It would be good to get thousands
of colours.
- The colours in the wheel should have a smooth transition across the wheel.

I was thinking of building the wheel in some other app and screen
capturing it and then using some arithmetic to work out the colour under
the cursor but the numbers are killing me.

Can anyone either tell me where I can find one or how I can go about
building one?

Andrew Poulos

 

[RobB]

I need to build a colour wheel. It has these specs:
- The user needs to be able to select a colour from it
- It should show as many colours as reasonable. The client wanted the
entire 16 million+ colour spectrum but I pointed out that at one colour
per pixel that's a 2,000 pixel square. It would be good to get thousands
of colours.
- The colours in the wheel should have a smooth transition across the wheel.

I was thinking of building the wheel in some other app and screen
capturing it and then using some arithmetic to work out the colour under
the cursor but the numbers are killing me.

Can anyone either tell me where I can find one or how I can go about
building one?

Andrew Poulos

Always kind of liked this one:

http://simplythebest.net/scripts/DHTML_scripts/javascripts/javascript_115.html

Uses a jpg - but it's a reasonable weight for the task.

 

[RobB]

Not a wheel, but...

http://www.daltonlp.com/daltonlp.cgi?item_type=1&item_id=174

 

[Richard Cornford]

Andrew Poulos wrote:

... . The client wanted the entire 16 million+
colour spectrum but I pointed out that
at one colour per pixel that's a 2,000 pixel
square. ...

I was thinking of building the wheel in some other app and screen
capturing it and then using some arithmetic to work out the colour
under the cursor but the numbers are killing me.

<snip>

Apparently the number are killing you. A square showing all of the 24
bit pallet would be 4096 pixels square.

Picking from a pre-created image, and deducing the colors form the
offsets is still going to be the most practical approach (if you insist
on having a 'color wheel' to start with) as otherwise you would need
thousands of individually colored HTML elements (table cells or DIVs or
something) and that would be a monstrous download (or an really slow
script) just for a minor GUI widget.

Richard.