C Program To Convert (R, G, B) To (C, M, Y, K) Color Format

In digital world colors are specified in Red-Green-Blue (RGB) format, with values of R, G, B varying on an integer scale from 0 to 255. In print publishing the colors are mentioned in Cyan-Magenta-Yellow-Black (CMYK) format, with values of C, M, Y and K varying on a real scale from 0.0 to 1.0. Write a C program that converts RGB color to CMYK color as per the following formulae:

White = Max(Red/255, Green/255, Blue/255);
Cyan = (White – Red/255) / White;
Magenta = (White – Green/255) / White;
Yellow = ( White – Blue/255) / White;
Black = 1-White

Note that if the RGB values are all 0, then the CMY values are all 0 and the K value is 1.

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Expected Output for the Input

User Input:
Enter values for Red, Green and Blue(RGB) in Range 0 – 255
41
14
41

Output:
CMYK = (0.000000, 0.658537, 0.000000, 0.839216)

Video Tutorial: C Program To Convert (R, G, B) To (C, M, Y, K) Color Format

Source Code: C Program To Convert (R, G, B) To (C, M, Y, K) Color Format

#include < stdio.h >

int main()
{
    float red, green, blue;
    float white, cyan, magenta, yellow, black;
    float max;

    printf("Enter values for Red, Green and Blue(RGB) in Range 0 - 255\n");
    scanf("%f%f%f", &red, &green, &blue);

    if(red == 0 && green == 0 && blue == 0)
    {
        cyan   = magenta = yellow = 0;
        black  = 1;
        black  = 1;
    }
    else
    {
        red    = red   / 255;
        green  = green / 255;
        blue   = blue  / 255;

        max    = red;
        if(green > max)
        {
            max = green;
        }

        if(blue > max)
        {
            max = blue;
        }

        white   = max;

        cyan    = (white - red)  / white;
        magenta = (white - green)/ white;
        yellow  = (white - blue) / white;

        black   = 1 - white;

    }

    printf("CMYK = (%f, %f, %f, %f)\n",
            cyan, magenta, yellow, black);

    return 0;
}

Output 1:
Enter values for Red, Green and Blue(RGB) in Range 0 – 255
255
255
255
CMYK = (0.000000, 0.000000, 0.000000, 0.000000)

Output 2:
Enter values for Red, Green and Blue(RGB) in Range 0 – 255
0
0
0
CMYK = (0.000000, 0.000000, 0.000000, 1.000000)

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