How do i convert RGB color to hexadecimal in Java

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I've searched everywhere, but i couldn't find a suiting solution.

I have a RGB color that i want to convert to this format: 0xffffffff

Many answers convert it to this format: #ffffff

Does anyone know how to convert it to this format (0xffffffff)?

EDIT: Solved! I actually needed a int but i accidentally said string, woopsie. Seems to work now, thanks!

Snippet:

double frequency = .3;
double r = 255;
double g = 255;
double b = 255;
for (int i = 0; i < 32; ++i)
{
    // I am trying to make a rainbow, hence this for loop and the Math.sin
    r = Math.sin(frequency*i + 0) * 127 + 128;
    g = Math.sin(frequency*i + 2) * 127 + 128;
    b = Math.sin(frequency*i + 4) * 127 + 128;
    int red = (int)r;
    int green = (int)g;
    int blue = (int)b;

    // converting, outputs a string

    System.out.println(result);
}
java
string
int
hex
rgb
asked on Stack Overflow Mar 14, 2020 by Lucaskyy • edited Mar 14, 2020 by Lucaskyy

3 Answers

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In case you want the number not as an string, but as an int:

0xRRGGBB

RR, GG, BB each represent a value between 0 - 255 (the RGB-values). Each digit of the hex-number can have values ranging from 0 - 16, means that you will need to store numbers up to 16 ^ 6 = 16.777.216‬ -> dataype int should be ok.
Then simply make your int:

int hexval = red * 65536 + green * 256 + blue;

Optionally you can output it:

System.out.printf("0x%06X\n", hexval);
answered on Stack Overflow Mar 14, 2020 by itzFlubby
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public class Main {
    public static void main(String[] args) {
        double frequency = .3;
        int red = (int) (Math.sin(frequency * 10 + 0) * 127 + 128);
        int green = (int) (Math.sin(frequency * 10 + 2) * 127 + 128);
        int blue = (int) (Math.sin(frequency * 10 + 4) * 127 + 128);
        int result = Integer.parseInt(String.format("%02x%02x%02x", red, green, blue), 16);

        System.out.println("Decimal representation: " + result);
        System.out.println("Hexdecimal representation: " + String.format("0x%06x", result));
    }
}

Output:

Decimal representation: 9504467
Hexdecimal representation: 0x9106d3
answered on Stack Overflow Mar 14, 2020 by Arvind Kumar Avinash • edited Mar 14, 2020 by Arvind Kumar Avinash
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public static int colorToInt(int r, int g, int b) {
    int result = 0;
    result += r;
    result = result << 8;
    result += g;
    result = result << 8;
    result += b;

    return result;
}

Here's an example:

System.out.println(0xffffff); // 16777215
System.out.println(colorToInt(255, 255, 255)); // 16777215

Repl: https://repl.it/repls/IrritatingTwinConsulting.

This function accepts int, instead of double, but I don't think it's a problem. Hope I understood your question correctly.

answered on Stack Overflow Mar 14, 2020 by Тимофей Сосновский

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