Question

how to Generate Color Spectrum using Python

as a png picture. But the width and height of the picture should be adjustable. The Colors should be used as hex values like the HTML Color-Code (for example #FF0000).

I know how the scale works but i think there are already any solutions how to count up the blue to red, then counting down red etc. in a resolution that acquires the needed width of the picture.

For generating the Picture i thought about PIL:

from PIL import Image

im = Image.new("RGB", (width, height))

im.putdata(DEC_tuples)

im.save("Picture", "PNG")

Are there any existing working solutions available?

Answer 1

Found a solution by myself and it works pretty well, the generated image will become a new width because I won't generate float-numbers.

from PIL import Image

width = 300 # Expected Width of generated Image

height = 100 # Height of generated Image

specratio = 255*6 / width

print ("SpecRatio: " + str(specratio))

red = 255

green = 0

blue = 0

colors = []

step = round(specratio)

for u in range (0, height):

    for i in range (0, 255*6+1, step):

        if i > 0 and i <= 255:

            blue += step

        elif i > 255 and i <= 255*2:

            red -= step

        elif i > 255*2 and i <= 255*3:

            green += step

        elif i > 255*3 and i <= 255*4:

            blue -= step

        elif i > 255*4 and i <= 255*5:

            red += step

        elif i > 255*5 and i <= 255*6:

            green -= step

        colors.append((red, green, blue))

newwidth = int(i/step+1) # Generated Width of Image without producing Float-Numbers

print (str(colors))

im = Image.new("RGB", (newwidth, height))

im.putdata(colors)

im.save("Picture", "PNG")