Posted on by Kalkicode
Code Conversion

Hex to RGB color

In computer programming and web development, colors are often represented using hexadecimal (hex) codes. However, sometimes it's necessary to convert these hex color codes to their corresponding RGB (Red, Green, Blue) values for various purposes. In this article, we will discuss the problem of converting hex color codes to RGB values and provide a solution in the form of an algorithm and pseudocode.

Problem Statement

The problem is to write a program that takes a hex color code as input and converts it to its RGB representation. The hex color code is a six-digit alphanumeric value that represents the intensity of the three primary colors (red, green, and blue) used to create a specific color. Each digit in the hex code represents four bits, allowing for 16 possible values (0-9, A-F).

For example, the hex code "FA8072" represents a reddish color, "03FFA2" represents a bluish-green color, and "FFFFFF" represents white.

Example:

Input: "FA8072"

Output: R: 250, G: 128, B: 114

Algorithm and Pseudocode

To convert a hex color code to RGB, we can follow these steps:

  1. Define a function color_code that takes a character as input and returns the decimal value of the corresponding hex digit.
  2. Define a function hex_to_rgb that takes a hex color code as input.
  3. Inside the hex_to_rgb function, calculate the RGB values using the color_code function and the given hex color code.
  4. Display the calculated RGB values.
  5. Define the main function and test the hex_to_rgb function with sample hex color codes.

Here is the pseudocode for the algorithm:


function color_code(color):
    if color is a number:
        return (decimal value of the digit)
    else if color is a lowercase letter:
        return (decimal value of the letter)
    else if color is an uppercase letter:
        return (decimal value of the letter)
    else:
        return -1

function hex_to_rgb(hex):
    if length of hex is not equal to 6:
        print "Invalid Hex color code"
        return
    else:
        r = (color_code(hex[0]) * 16) + color_code(hex[1])
        g = (color_code(hex[2]) * 16) + color_code(hex[3])
        b = (color_code(hex[4]) * 16) + color_code(hex[5])
        print "Hex:", hex
        print "R:", r, "G:", g, "B:", b

function main():
    hex_to_rgb("FA8072")
    hex_to_rgb("03FFA2")
    hex_to_rgb("FFFFFF")

Code Solution

Here given code implementation process.

// C program 
// Hex to RGB color
#include <stdio.h>
#include <string.h>

// Returns the decimal code of given hex
int color_code(char color)
{
	if (color >= '0' && color <= '9')
	{
		//When hex digit, is a number
		return (color - 48);
	}
	else if (color >= 'a' && color <= 'f')
	{
		//when of hex digit is an lowercase letter
		return (color - 87);
	}
	else if (color >= 'A' && color <= 'F')
	{
		//when of hex digit is an uppercase letter
		return (color - 55);
	}
	// When not a valid code
	return -1;
}
// Converting hex color to RGB color
void hex_to_rgb(char *hex)
{
	// Get the length
	int digits = strlen(hex);
	if (digits != 6)
	{
		printf("\n Invalid Hex color code [%s]\n", hex);
		return;
	}
	// Calculate color code
	int r = (color_code(hex[0]) *16) + (color_code(hex[1]));
	int g = (color_code(hex[2]) *16) + (color_code(hex[3]));
	int b = (color_code(hex[4]) *16) + (color_code(hex[5]));
	// Display calculated result
	printf(" Hex : %s \n R : %d  G : %d  B : %d \n", hex, r, g, b);
}
int main()
{
	// Test Case
	hex_to_rgb("fa8072");
	hex_to_rgb("03ffa2");
	hex_to_rgb("ffffff");
	return 0;
}

Output

 Hex : fa8072
 R : 250  G : 128  B : 114
 Hex : 03ffa2
 R : 3  G : 255  B : 162
 Hex : ffffff
 R : 255  G : 255  B : 255
/*
  Java Program
  RGB to HSL color
*/
public class ColorConversion
{
	// Returns the decimal code of given hex
	public int color_code(char color)
	{
		if (color >= '0' && color <= '9')
		{
			//When hex digit, is a number
			return (color - 48);
		}
		else if (color >= 'a' && color <= 'f')
		{
			//when of hex digit is an lowercase letter
			return (color - 87);
		}
		else if (color >= 'A' && color <= 'F')
		{
			//when of hex digit is an uppercase letter
			return (color - 55);
		}
		// When not a valid code
		return -1;
	}
	// Converting hex color to RGB color
	public void hex_to_rgb(String hex)
	{
		// Get the length
		int digits = hex.length();
		if (digits != 6)
		{
			System.out.print("\n Invalid Hex color code [" + hex + "]\n");
			return;
		}
		// Calculate color code
		int r = (color_code(hex.charAt(0)) * 16) + (color_code(hex.charAt(1)));
		int g = (color_code(hex.charAt(2)) * 16) + (color_code(hex.charAt(3)));
		int b = (color_code(hex.charAt(4)) * 16) + (color_code(hex.charAt(5)));
		// Display calculated result
		System.out.print(" Hex : " + hex + " \n R : " + r + " G : " + g + " B : " + b + " \n");
	}
	public static void main(String[] args)
	{
		ColorConversion color = new ColorConversion();
		// Test Case
		color.hex_to_rgb("fa8072");
		color.hex_to_rgb("03ffa2");
		color.hex_to_rgb("ffffff");
	}
}

Output

 Hex : fa8072
 R : 250 G : 128 B : 114
 Hex : 03ffa2
 R : 3 G : 255 B : 162
 Hex : ffffff
 R : 255 G : 255 B : 255
// Include header file
#include <iostream>
#include<string.h>

using namespace std;
/*
  C++ Program
  RGB to HSL color
*/

class ColorConversion
{
	public:
		// Returns the decimal code of given hex
		int color_code(char color)
		{
			if (color >= '0' && color <= '9')
			{
				//When hex digit, is a number
				return (color - 48);
			}
			else if (color >= 'a' && color <= 'f')
			{
				//when of hex digit is an lowercase letter
				return (color - 87);
			}
			else if (color >= 'A' && color <= 'F')
			{
				//when of hex digit is an uppercase letter
				return (color - 55);
			}
			// When not a valid code
			return -1;
		}
	// Converting hex color to RGB color
	void hex_to_rgb(string hex)
	{
		// Get the length
		int digits = hex.size();
		if (digits != 6)
		{
			cout << "\n Invalid Hex color code [" << hex << "]\n";
			return;
		}
		// Calculate color code
		int r = (this->color_code(hex[0]) *16) + (this->color_code(hex[1]));
		int g = (this->color_code(hex[2]) *16) + (this->color_code(hex[3]));
		int b = (this->color_code(hex[4]) *16) + (this->color_code(hex[5]));
		// Display calculated result
		cout << " Hex : " << hex << " \n R : " << r << " G : " << g << " B : " << b << " \n";
	}
};
int main()
{
	ColorConversion color = ColorConversion();
	// Test Case
	color.hex_to_rgb("fa8072");
	color.hex_to_rgb("03ffa2");
	color.hex_to_rgb("ffffff");
	return 0;
}

Output

 Hex : fa8072
 R : 250 G : 128 B : 114
 Hex : 03ffa2
 R : 3 G : 255 B : 162
 Hex : ffffff
 R : 255 G : 255 B : 255
// Include namespace system
using System;
/*
  C# Program
  RGB to HSL color
*/
public class ColorConversion
{
	// Returns the decimal code of given hex
	public int color_code(char color)
	{
		if (color >= '0' && color <= '9')
		{
			//When hex digit, is a number
			return (color - 48);
		}
		else if (color >= 'a' && color <= 'f')
		{
			//when of hex digit is an lowercase letter
			return (color - 87);
		}
		else if (color >= 'A' && color <= 'F')
		{
			//when of hex digit is an uppercase letter
			return (color - 55);
		}
		// When not a valid code
		return -1;
	}
	// Converting hex color to RGB color
	public void hex_to_rgb(String hex)
	{
		// Get the length
		int digits = hex.Length;
		if (digits != 6)
		{
			Console.Write("\n Invalid Hex color code [" + hex + "]\n");
			return;
		}
		// Calculate color code
		int r = (color_code(hex[0]) * 16) + (color_code(hex[1]));
		int g = (color_code(hex[2]) * 16) + (color_code(hex[3]));
		int b = (color_code(hex[4]) * 16) + (color_code(hex[5]));
		// Display calculated result
		Console.Write(" Hex : " + hex + " \n R : " + r + " G : " + g + " B : " + b + " \n");
	}
	public static void Main(String[] args)
	{
		ColorConversion color = new ColorConversion();
		// Test Case
		color.hex_to_rgb("fa8072");
		color.hex_to_rgb("03ffa2");
		color.hex_to_rgb("ffffff");
	}
}

Output

 Hex : fa8072
 R : 250 G : 128 B : 114
 Hex : 03ffa2
 R : 3 G : 255 B : 162
 Hex : ffffff
 R : 255 G : 255 B : 255
<?php
/*
  Php Program
  RGB to HSL color
*/
class ColorConversion
{
	// Returns the decimal code of given hex
	public	function color_code($color)
	{
		if (ord($color) >= ord('0') && ord($color) <= ord('9'))
		{
			//When hex digit, is a number
			return (ord($color) - 48);
		}
		else if (ord($color) >= ord('a') && ord($color) <= ord('f'))
		{
			//when of hex digit is an lowercase letter
			return (ord($color) - 87);
		}
		else if (ord($color) >= ord('A') && ord($color) <= ord('F'))
		{
			//when of hex digit is an uppercase letter
			return (ord($color) - 55);
		}
		// When not a valid code
		return -1;
	}
	// Converting hex color to RGB color
	public	function hex_to_rgb($hex)
	{
		// Get the length
		$digits = strlen($hex);
		if ($digits != 6)
		{
			echo "\n Invalid Hex color code [". $hex ."]\n";
			return;
		}
		// Calculate color code
		$r = ($this->color_code($hex[0]) * 16) + ($this->color_code($hex[1]));
		$g = ($this->color_code($hex[2]) * 16) + ($this->color_code($hex[3]));
		$b = ($this->color_code($hex[4]) * 16) + ($this->color_code($hex[5]));
		// Display calculated result
		echo " Hex : ". $hex ." \n R : ". $r ." G : ". $g ." B : ". $b ." \n";
	}
}

function main()
{
	$color = new ColorConversion();
	// Test Case
	$color->hex_to_rgb("fa8072");
	$color->hex_to_rgb("03ffa2");
	$color->hex_to_rgb("ffffff");
}
main();

Output

 Hex : fa8072
 R : 250 G : 128 B : 114
 Hex : 03ffa2
 R : 3 G : 255 B : 162
 Hex : ffffff
 R : 255 G : 255 B : 255
/*
  Node Js Program
  RGB to HSL color
*/
class ColorConversion
{
	// Returns the decimal code of given hex
	color_code(color)
	{
		if ((color).charCodeAt(0) >= ('0').charCodeAt(0) && (color).charCodeAt(0) <= ('9').charCodeAt(0))
		{
			//When hex digit, is a number
			return ((color).charCodeAt(0) - 48);
		}
		else if ((color).charCodeAt(0) >= ('a').charCodeAt(0) && (color).charCodeAt(0) <= ('f').charCodeAt(0))
		{
			//when of hex digit is an lowercase letter
			return ((color).charCodeAt(0) - 87);
		}
		else if ((color).charCodeAt(0) >= ('A').charCodeAt(0) && (color).charCodeAt(0) <= ('F').charCodeAt(0))
		{
			//when of hex digit is an uppercase letter
			return ((color).charCodeAt(0) - 55);
		}
		// When not a valid code
		return -1;
	}
	// Converting hex color to RGB color
	hex_to_rgb(hex)
	{
		// Get the length
		var digits = hex.length;
		if (digits != 6)
		{
			process.stdout.write("\n Invalid Hex color code [" + hex + "]\n");
			return;
		}
		// Calculate color code
		var r = (this.color_code(hex[0]) * 16) + (this.color_code(hex[1]));
		var g = (this.color_code(hex[2]) * 16) + (this.color_code(hex[3]));
		var b = (this.color_code(hex[4]) * 16) + (this.color_code(hex[5]));
		// Display calculated result
		process.stdout.write(" Hex : " + hex + " \n R : " + r + " G : " + g + " B : " + b + " \n");
	}
}

function main()
{
	var color = new ColorConversion();
	// Test Case
	color.hex_to_rgb("fa8072");
	color.hex_to_rgb("03ffa2");
	color.hex_to_rgb("ffffff");
}
main();

Output

 Hex : fa8072
 R : 250 G : 128 B : 114
 Hex : 03ffa2
 R : 3 G : 255 B : 162
 Hex : ffffff
 R : 255 G : 255 B : 255
#   Python 3 Program
#   RGB to HSL color

class ColorConversion :
	#  Returns the decimal code of given hex
	def color_code(self, color) :
		if (ord(color) >= ord('0') and ord(color) <= ord('9')) :
			# When hex digit, is a number
			return (ord(color) - 48)
		
		elif(ord(color) >= ord('a') and ord(color) <= ord('f')) :
			# when of hex digit is an lowercase letter
			return (ord(color) - 87)
		
		elif(ord(color) >= ord('A') and ord(color) <= ord('F')) :
			# when of hex digit is an uppercase letter
			return (ord(color) - 55)
		
		#  When not a valid code
		return -1
	
	#  Converting hex color to RGB color
	def hex_to_rgb(self, hex) :
		#  Get the length
		digits = len(hex)
		if (digits != 6) :
			print("\n Invalid Hex color code [", hex ,"]")
			return
		
		#  Calculate color code
		r = (self.color_code(hex[0]) * 16) + (self.color_code(hex[1]))
		g = (self.color_code(hex[2]) * 16) + (self.color_code(hex[3]))
		b = (self.color_code(hex[4]) * 16) + (self.color_code(hex[5]))
		#  Display calculated result
		print(" Hex : ", hex ," \n R : ", r ," G : ", g ," B : ", b ," ")
	

def main() :
	color = ColorConversion()
	#  Test Case
	color.hex_to_rgb("fa8072")
	color.hex_to_rgb("03ffa2")
	color.hex_to_rgb("ffffff")

if __name__ == "__main__": main()

Output

 Hex :  fa8072
 R :  250  G :  128  B :  114
 Hex :  03ffa2
 R :  3  G :  255  B :  162
 Hex :  ffffff
 R :  255  G :  255  B :  255
#   Ruby Program
#   RGB to HSL color

class ColorConversion 
	#  Returns the decimal code of given hex
	def color_code(color) 
		if ((color).ord >= ('0').ord && (color).ord <= ('9').ord) 
			# When hex digit, is a number
			return ((color).ord - 48)
		elsif((color).ord >= ('a').ord && (color).ord <= ('f').ord) 
			# when of hex digit is an lowercase letter
			return ((color).ord - 87)
		elsif((color).ord >= ('A').ord && (color).ord <= ('F').ord) 
			# when of hex digit is an uppercase letter
			return ((color).ord - 55)
		end

		#  When not a valid code
		return -1
	end

	#  Converting hex color to RGB color
	def hex_to_rgb(hex) 
		#  Get the length
		digits = hex.length()
		if (digits != 6) 
			print("\n Invalid Hex color code [", hex ,"]\n")
			return
		end

		#  Calculate color code
		r = (self.color_code(hex[0]) * 16) + (self.color_code(hex[1]))
		g = (self.color_code(hex[2]) * 16) + (self.color_code(hex[3]))
		b = (self.color_code(hex[4]) * 16) + (self.color_code(hex[5]))
		#  Display calculated result
		print(" Hex : ", hex ," \n R : ", r ," G : ", g ," B : ", b ," \n")
	end

end

def main() 
	color = ColorConversion.new()
	#  Test Case
	color.hex_to_rgb("fa8072")
	color.hex_to_rgb("03ffa2")
	color.hex_to_rgb("ffffff")
end

main()

Output

 Hex : fa8072 
 R : 250 G : 128 B : 114 
 Hex : 03ffa2 
 R : 3 G : 255 B : 162 
 Hex : ffffff 
 R : 255 G : 255 B : 255 
/*
  Scala Program
  RGB to HSL color
*/
class ColorConversion
{
	// Returns the decimal code of given hex
	def color_code(color: Char): Int = {
		if (color >= '0' && color <= '9')
		{
			//When hex digit, is a number
			return (color - 48);
		}
		else if (color >= 'a' && color <= 'f')
		{
			//when of hex digit is an lowercase letter
			return (color - 87);
		}
		else if (color >= 'A' && color <= 'F')
		{
			//when of hex digit is an uppercase letter
			return (color - 55);
		}
		// When not a valid code
		return -1;
	}
	// Converting hex color to RGB color
	def hex_to_rgb(hex: String): Unit = {
		// Get the length
		var digits: Int = hex.length();
		if (digits != 6)
		{
			print("\n Invalid Hex color code [" + hex + "]\n");
			return;
		}
		// Calculate color code
		var r: Int = (this.color_code(hex(0)) * 16) + (this.color_code(hex(1)));
		var g: Int = (this.color_code(hex(2)) * 16) + (this.color_code(hex(3)));
		var b: Int = (this.color_code(hex(4)) * 16) + (this.color_code(hex(5)));
		// Display calculated result
		print(" Hex : " + hex + " \n R : " + r + " G : " + g + " B : " + b + " \n");
	}
}
object Main
{
	def main(args: Array[String]): Unit = {
		var color: ColorConversion = new ColorConversion();
		// Test Case
		color.hex_to_rgb("fa8072");
		color.hex_to_rgb("03ffa2");
		color.hex_to_rgb("ffffff");
	}
}

Output

 Hex : fa8072
 R : 250 G : 128 B : 114
 Hex : 03ffa2
 R : 3 G : 255 B : 162
 Hex : ffffff
 R : 255 G : 255 B : 255
/*
  Swift 4 Program
  RGB to HSL color
*/
class ColorConversion
{
	// Returns the decimal code of given hex
	func color_code(_ color: Character)->Int
	{
		if (color >= "0" && color <= "9")
		{
			//When hex digit, is a number
			return Int(UnicodeScalar(String(color))!.value) - 48;
		}
		else if (color >= "a" && color <= "f")
		{
			//when of hex digit is an lowercase letter
			return Int(UnicodeScalar(String(color))!.value) - 87;
		}
		else if (color >= "A" && color <= "F")
		{
			//when of hex digit is an uppercase letter
			return Int(UnicodeScalar(String(color))!.value) - 55;
		}
		// When not a valid code
		return -1;
	}
	// Converting hex color to RGB color
	func hex_to_rgb(_ hex_code: String)
	{
		// Get the length
		let digits: Int = hex_code.count;
		if (digits != 6)
		{
			print("\n Invalid Hex color code [", hex_code ,"]");
			return;
		}
      	let hex = Array(hex_code);
		// Calculate color code
		let r: Int = (self.color_code(hex[0]) * 16) + (self.color_code(hex[1]));
		let g: Int = (self.color_code(hex[2]) * 16) + (self.color_code(hex[3]));
		let b: Int = (self.color_code(hex[4]) * 16) + (self.color_code(hex[5]));
		// Display calculated result
		print(" Hex : ", hex_code ," \n R : ", r ," G : ", g ," B : ", b ," ");
	}
}
func main()
{
	let color: ColorConversion = ColorConversion();
	// Test Case
	color.hex_to_rgb("fa8072");
	color.hex_to_rgb("03ffa2");
	color.hex_to_rgb("ffffff");
}
main();

Output

 Hex :  fa8072
 R :  250  G :  128  B :  114
 Hex :  03ffa2
 R :  3  G :  255  B :  162
 Hex :  ffffff
 R :  255  G :  255  B :  255
/*
  Kotlin Program
  RGB to HSL color
*/
class ColorConversion
{
	// Returns the decimal code of given hex
	fun color_code(color: Char): Int
	{
		if (color >= '0' && color <= '9')
		{
			//When hex digit, is a number
			return (color.toInt() - 48);
		}
		else
		if (color >= 'a' && color <= 'f')
		{
			//when of hex digit is an lowercase letter
			return (color.toInt() - 87);
		}
		else
		if (color >= 'A' && color <= 'F')
		{
			//when of hex digit is an uppercase letter
			return (color.toInt() - 55);
		}
		// When not a valid code
		return -1;
	}
	// Converting hex color to RGB color
	fun hex_to_rgb(hex: String): Unit
	{
		// Get the length
		var digits: Int = hex.count();
		if (digits != 6)
		{
			print("\n Invalid Hex color code [" + hex + "]\n");
			return;
		}
		// Calculate color code
		var r: Int = (this.color_code(hex[0]) * 16) + (this.color_code(hex[1]));
		var g: Int = (this.color_code(hex[2]) * 16) + (this.color_code(hex[3]));
		var b: Int = (this.color_code(hex[4]) * 16) + (this.color_code(hex[5]));
		// Display calculated result
		print(" Hex : " + hex + " \n R : " + r + " G : " + g + " B : " + b + " \n");
	}
}
fun main(args: Array<String>): Unit
{
	var color: ColorConversion = ColorConversion();
	// Test Case
	color.hex_to_rgb("fa8072");
	color.hex_to_rgb("03ffa2");
	color.hex_to_rgb("ffffff");
}

Output

 Hex : fa8072
 R : 250 G : 128 B : 114
 Hex : 03ffa2
 R : 3 G : 255 B : 162
 Hex : ffffff
 R : 255 G : 255 B : 255

Output Explanation

The given program converts the hex color codes to their respective RGB values. The provided test cases demonstrate this conversion:

  • Hex code "FA8072" corresponds to the RGB values R: 250, G: 128, B: 114.
  • Hex code "03FFA2" corresponds to the RGB values R: 3, G: 255, B: 162.
  • Hex code "FFFFFF" corresponds to the RGB values R: 255, G: 255, B: 255, representing the color white.

Time Complexity Analysis

The time complexity of the provided code is primarily determined by the length of the hex color code, which is constant (6 characters). Therefore, the time complexity of the hex_to_rgb function is O(1).

Finally

In this article, we discussed the problem of converting hex color codes to RGB values. We provided an algorithm and pseudocode to solve the problem, along with an explanation of the program's output. The provided code demonstrates a simple and efficient way to convert hex color codes to their corresponding RGB values, allowing developers to work with colors more flexibly in their programs or web applications.

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