Proper RGB values from gradient

So I am just playing around with the gradient node and noticed something strange.

If I double click one of the control points in the gradient you can set the ColorLeft and ColorRight.

If I do that and pick for example white for ColorLeft and black for ColorRight, then the output is not RGB values anymore for pure white, but the string "white", thus making any calculations using the values impossible.

Is there a way to:

a) have the gradient always output numerical values

b) convert rbg values mixed with strings of pure colors (white, black, etc.) to only numerical values

Thanks, Armin.

Replies to This Discussion

Permalink Reply by Armin Seltz on December 17, 2014 at 7:00am

Ok, so I just noticed if I enter 255,255,255 it uses the numerical values in the output. Strangely if you enter something invalid, for example just accidentally put "255.255.255" it says "255.255.255 is not a valid value for Int32". But how can a string be a valid Int32?

This must be some sort of system thingy. Very strange indeed.

PS: I should mention that the reason I need numerical values is that I just need the Lightness value of the color. To be able to convert RGB to HSL I need proper values though.

Permalink Reply by Danny Boyes on December 17, 2014 at 7:22am

What you are seeing is the Panel being clever and interpreting the value as White. If you plugged it into a Colour Param on any component that requires it it will be the correct RGB value.

Permalink Reply by Armin Seltz on December 17, 2014 at 8:06am

Ah ok there is a color split node. Doh!

It converts it to numbers. Ok, so now its easy to convert to HSL using 3 inputs instead of 1.

Thanks!

ps: for future reference if someone comes across this, the code inside the C# node is:

System.Drawing.Color color = Color.FromArgb(R, G, B);

H = color.GetHue();
S = color.GetSaturation();
L = color.GetBrightness();

Permalink Reply by Danny Boyes on December 17, 2014 at 8:28am

there is a component for this but V is used as the Output for L

Permalink Reply by Armin Seltz on December 17, 2014 at 8:39am

Ok, thats true. But HSV is not the same as HSL ;)

Actually it seems that the HSV component is actually outputting HSL and not HSV.

http://en.wikipedia.org/wiki/HSL_and_HSV

I think this is why there is a "split AHSV" and a "color AHSL" node. Why not have a split and join for both, but a split for one and a join for the other!?

Permalink Reply by Danny Boyes on December 17, 2014 at 8:44am

Is V not the value for Brightness? your code is color.GetBrightness()

Permalink Reply by Armin Seltz on December 17, 2014 at 9:01am

That is true. But the V is not the same as L. So you're right, that I can use the HSV component in this case. But it means that the HSV component should be called HSL (see below).

Permalink Reply by Armin Seltz on December 17, 2014 at 8:58am

Ok, I knew it. The HSV component should be named HSL!

As you can see the V value for the red color is 100, but the V value that HSV outputs is actually the L value of 0.5.

Wow, nobody noticed this before?

Permalink Reply by Danny Boyes on December 17, 2014 at 9:08am

Report it as a bug

Permalink Reply by Armin Seltz on December 17, 2014 at 9:11am

Just did ;)

Permalink Reply by Danny Boyes on December 17, 2014 at 9:54am

It would seem Daniel noticed this last week, but you would need to translate the post to see that: http://www.grasshopper3d.com/forum/topics/assign-a-number-to-a-colo...

Permalink Reply by Armin Seltz on December 17, 2014 at 8:09am

Ah, but its still strange that it is only "clever" for the first color and not the ones after that. Note that it says "black" in the first 2 lines, but then "255,255,255" in the lines after that.