I wanted to create a circle with RGB color effect (Just like RBG color pallet) in SFML. but could not find any method to make it except using an image.

First, I Tried making a RGB rectangle (Just like RBG color pallet), I used several small Rectangles to make the effect work (let know if there’s an efficient method to do it), but now I want to make Circle, am pasting the code of Rectangle here:

#include <SFML/Graphics.hpp>

//Global Variable and define's
#define windowSize 450
#define rectSize 1.0f
int colorRange = 255;

int main()
{
    //Creating new Window
    sf::RenderWindow window(sf::VideoMode(windowSize, windowSize), "Colors", sf::Style::Close | sf::Style::Resize);
    
    sf::View mainView = window.getDefaultView();
        
    while (window.isOpen())
    {
        sf::Event event;
        while (window.pollEvent(event))
        {
            if (event.type == sf::Event::Closed)
            //Close Window Code
                window.close();
            else if(event.type == sf::Event::Resized)
            {
                //View Resize Code
                mainView.setSize
                (
                    static_cast<float> (event.size.width), 
                    static_cast<float> (event.size.height)
                );
                mainView.setCenter
                (
                    static_cast<float> (event.size.width) / 2,
                    static_cast<float> (event.size.height)/ 2
                );
                
            }
            window.setView(mainView);
                
        }
        

        for(int i = 0; i < colorRange; i++)
        {
            for(int j = 0; j < colorRange; j++)
            {
            
                    sf::RectangleShape shape(sf::Vector2f(rectSize, rectSize));
                    shape.setPosition(sf::Vector2f(i * rectSize, j * rectSize));
                    shape.setFillColor(sf::Color(i, j, 127, 255));
                    window.draw(shape);                
            
                
            }
        }       
        window.display();
        window.clear(sf::Color::White);
    }

    return 0;
}