algorithmic modeling for Rhino

Grasshopper 2.0 (alpha) Colour Picker

Putting the various colour models I coded up together into a single UI. Still a long way to go, but it's getting close to usable.

Colour models implemented so far: sRGB, HSV, CMY, L*a*b*, H*SP (similar to HSL, but with a human-centric luminance metric and non-linear hue angles) and Yxy (aka CIE Chromaticity).

I'm still hoping to add two more models of my own devising, one that should help with picking nice shades of various browns (ever notice how hard that is in conventional pickers?) and a multi-dimensional object which provides quick access to a whole range of modification axes.

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Comment by David Rutten on March 24, 2017 at 3:00am

1) Just straight up inversion of RGB at the moment; C=1-R, M=1-G, Y=1-B. But all the coordinate->colour mapping is fully abstracted so adding more spaces or more functionality to an existing space is pretty easy.

2) Do note that the colour picker outputs RGB values (which is the only type of colour the rest of Rhino understands), so everything ultimately gets converted (and clipped) to the sRGB gamut. The colour models themselves are more flexible and could be repurposed for more advanced stuff, the the picker is purely a UI element.

3) Sure. I always liked the way Xara solved this. There's a default palette, easily editable/extendible by the user, and colours can be defined as modifications of other colours. So you could for example inherit the hue from a colour named "base" but lower the luminance slightly.

4) This would be palette picking, not colour picking. There's already a palette picker in GH1, I imagine a similar object will be available in GH2 at some point.

5) The sRGB gamut is outlined in the Yxy space, but I'm currently not drawing it in the L*a*b* cube. This is mostly because it's a complicated 3D shape which I still have to compute/describe in a way that lends itself for quick display.

Comment by Miguel Rus on March 23, 2017 at 10:15pm

Looking great so far.

1.- What kind of conversion are you using for CMY to RGB?

2.- It will be great to have in the CIE panel the the CMY colour Space marked. (it would be great to have the K value as this makes CAD prints sharper. I know this is a Rhino thing, but just mentioning it here.)

3.- I would personally love to have a predefined section (Put the work in once and get it done)

4.- Colopicking option with Analogue/Triad/Complimentary options. Similar to

5.- Would be great to know what colours do not translate properly between CMYK and RGB. The ones that fall within the CMYK and RGB colours spaces.

For colour picking I normally use the HSL as I find it the easiest one to create Shades of any colour.

My two cents.

Graphics look stunning btw:)

Comment by David Rutten on March 23, 2017 at 6:57pm

Ignore the icons for now. It's too bloody cumbersome to program nice ones by hand, which is the only method that works at the moment.





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