# Re: [pygame] Red-to-violet color palette

Oh okay. You don't want to go from red straight to violet, you want to go through the colors of the rainbow, ie, go around the color wheel the long way. Here's one quick, approximate way to pull it off. You can tweak it as you like:

norm = lambda x: min(max(int((x+1)*128),0),255)
s = lambda t: math.sin(2*math.pi*t)
spec = lambda t: (norm(s(t*0.9+0.2)), norm(s(t*0.9+0.9)), norm(s(t*0.9+0.5)))
palette = tuple(spec(x/256.) for x in range(256))

to test:

screen = pygame.display.set_mode((256,100))
for x in range(256):
pygame.draw.line(screen, palette[x], (x,0), (x,100))
pygame.display.flip()

-Christopher

On Fri, Jul 13, 2012 at 12:55 PM, Ricardo Franco wrote:
I dont know if I'm understanding well .. What I want is this:

"Building a colormap containing 256 colors is quite a chore, but the ColorUtils library
(http://code.google.com/p/colorutils/) can generate several predefined maps. Figure 20
employs the colormap returned by ColorUtils.getSpectrum(), which colorizes the
white to black range using the red-to-violet spectrum. This means that objects in the
depth map close to the Kinect will be rendered red or orange, while those further
away will be green, blue, or violet. Those without depth measures (perhaps because
they are too close to the Kinect) will be rendered as red."

(the example I took from pdf is in JAVA)

It says values near (the first values) are red or orange and the values far (the last values) will be green, blue or violet.
By near and far, I mean the iterations of i (0 to 255)

2012/7/13 Christopher Night
According to Wikipedia, violet is (127, 0, 255), so this should work:

tuple((255-(i+1)//2, 0, i) for i in range(256))

-Christopher

On Fri, Jul 13, 2012 at 12:20 PM, Ricardo Franco wrote:
I would like to know how to build a specifc color palette, its the red-to-violet color palette.
To build the grayscale color palette I use:

grayscale_palette = tuple([(i, i, i) for i in range(256)])

How do to get the red-to-violet color palette?

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