ColorBlocks.java Source code

Introduction

Here is the source code for ColorBlocks.java

Source

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.Rectangle2D;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class ColorBlocks extends JPanel {
    public void paint(Graphics g) {
        Graphics2D g2 = (Graphics2D) g;

        Dimension d = getSize();
        g2.translate(d.width / 2, d.height / 2);

        Color[] colors = { Color.white, Color.lightGray, Color.gray, Color.darkGray, Color.black, Color.red,
                Color.pink, Color.orange, Color.yellow, Color.green, Color.magenta, Color.cyan, Color.blue };

        float size = 25;
        float x = -size * colors.length / 2;
        float y = -size * 3 / 2;

        // Show all the predefined colors.
        for (int i = 0; i < colors.length; i++) {
            Rectangle2D r = new Rectangle2D.Float(x + size * (float) i, y, size, size);
            g2.setPaint(colors[i]);
            g2.fill(r);
        }

        //a linear gradient.
        y += size;
        Color c1 = Color.yellow;
        Color c2 = Color.blue;
        for (int i = 0; i < colors.length; i++) {
            float ratio = (float) i / (float) colors.length;
            int red = (int) (c2.getRed() * ratio + c1.getRed() * (1 - ratio));
            int green = (int) (c2.getGreen() * ratio + c1.getGreen() * (1 - ratio));
            int blue = (int) (c2.getBlue() * ratio + c1.getBlue() * (1 - ratio));
            Color c = new Color(red, green, blue);
            Rectangle2D r = new Rectangle2D.Float(x + size * (float) i, y, size, size);
            g2.setPaint(c);
            g2.fill(r);
        }

        // Show an alpha gradient.
        y += size;
        c1 = Color.red;
        for (int i = 0; i < colors.length; i++) {
            int alpha = (int) (255 * (float) i / (float) colors.length);
            Color c = new Color(c1.getRed(), c1.getGreen(), c1.getBlue(), alpha);
            Rectangle2D r = new Rectangle2D.Float(x + size * (float) i, y, size, size);
            g2.setPaint(c);
            g2.fill(r);
        }

        // Draw a frame around the whole thing.
        y -= size * 2;
        Rectangle2D frame = new Rectangle2D.Float(x, y, size * colors.length, size * 3);
        g2.setPaint(Color.black);
        g2.draw(frame);
    }

    public static void main(String[] args) {
        JFrame f = new JFrame();
        f.getContentPane().add(new ColorBlocks());
        f.setSize(350, 250);
        f.show();
    }
}