CODEWITHSUNDEEP
pythonpygamergb
Liam Jess
Liam Jess

Reputation: 27

RGB cycle python

Does anyone know how to cycle through RGB values in python? Ex. R = 255, G = 255, B = 255

R -= 1 until 0 and then go back up and then make G go down and so on?

(This is for text colour in pygame)

Upvotes: 2

Views: 2311

Answers (3)

JeanExtreme002
JeanExtreme002

Reputation: 231

You can use max() to get the largest number within the tuple and subtract each number until all are equal to or less than zero, like this:

RGB = (255,200,201)

red = RGB[0]
green = RGB[1]
blue = RGB[2]

step = -1

for i in range( max(RGB) * 2 + 2):

    print(
        "R:",red if red > 0 else 0,
        "G:",green if green > 0 else 0,
        "B:",blue if blue > 0 else 0
        )

    if all( map( lambda x: True if x < 0 else False, [red,green,blue] ) ):
        step = 1

    red += step
    green += step
    blue += step

As you can see, after all numbers are equal to or less than zero, the variable "step" is set to 1. This way we can make the numbers go back to their original values ​​by summing them.

Upvotes: 2

Kingsley
Kingsley

Reputation: 14906

It's a fairly easy shift to do - add some amount to each component of the colour, then ensure it is still within the legal bounds of the colour-value. Here I've assumed 8-bit colour, so the valid range is 0-255. Obviously if the code needed say 16 bit colour, the range would be bigger.

def shiftColour( colour, level_shift=-1 ):
    """ Return the colour with each component shifted (with boundary looping)"""
    red, green, blue = colour

    red += level_shift     # handle cycling in +/- for any level_shift
    if ( red < 0 ):
        red = 255
    elif ( red > 255 ):
        red = 0

    green += level_shift
    if ( green < 0 ):
        green = 255
    elif ( green > 255 ):
        green = 0

    blue += level_shift
    if ( blue < 0 ):
        blue = 255
    elif ( blue > 255 ):
        blue = 0

    return ( red, green, blue )   # re-combine, back into a colour

Shifting back down from the high-point is just a matter of remembering where the cycle is at. You probably don't want to use the last say 50 values, since the colour would be mostly black.

### Main
colour = ( 255, 245, 235 )
delta  = 1
for i in range( 300 ):
    colour = shiftColour( colour, delta )
    print("R=%d, G=%d, B=%d" % ( colour[0], colour[1], colour[2] ) )
    if ( i % 50 == 0 ):
        delta *= -1
        print( "direction-change" )

Upvotes: 2

GTA.sprx
GTA.sprx

Reputation: 827

Something like this?

r = 255
g = 255
b = 255
while(r>0):
    r-=1
    print("Red: %s" %r)
    if(r==0):
        while(g>0):
            g-=1
            print("Green: %s" %g)
            if(g==0):
                while(b>0):
                    b-=1
                    print("Blue: %s" %b)

I'm sure you can modify this abit to make it have a looping fade effect if that's what you're looking for.

Upvotes: 1

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