[java]classe GradientPaint

package panelDegrade;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.HeadlessException;

import javax.swing.JFrame;

public class MainView extends JFrame {
	private Container c;

	private GradientPanel gradientPanel;

	public MainView() throws HeadlessException {
		super("Démo de dégradé");
		initialize();
	}

	private void initialize() {
		c = getContentPane();
		setDefaultCloseOperation(EXIT_ON_CLOSE);
		c.setLayout(new BorderLayout());
	}

	public void setColorChoicePanel(ColorChoicePanel colorchoicePanel) {
		c.add(colorchoicePanel, BorderLayout.NORTH);
	}

	public void setGradientPanel(GradientPanel gradientPanel) {
		this.gradientPanel = gradientPanel;
		c.add(gradientPanel, BorderLayout.CENTER);
	}

	public void setColor1(Color c1) {
		gradientPanel.setColor1(c1);
	}

	public void setColor2(Color c2) {
		gradientPanel.setColor2(c2);
	}

	public static void main(String[] args) {
		MainView demo = new MainView();
		ColorChoicePanel colorChoicePanel = new ColorChoicePanel(demo);
		GradientPanel gradientPanel = new GradientPanel();
		gradientPanel.setPreferredSize(new Dimension(640, 480));
		demo.setColorChoicePanel(colorChoicePanel);
		demo.setGradientPanel(gradientPanel);
		demo.pack();
		demo.setVisible(true);
	}
}

package panelDegrade;

import java.awt.Color;
import java.awt.GradientPaint;
import java.awt.Graphics;
import java.awt.Graphics2D;

import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;

public class GradientPanel extends JPanel {
	private Color color1;
	private Color color2;
	

	public GradientPanel( ) {
		this.color1 = Color.black;
		this.color2 = Color.black;
		this.add(new JLabel("Hello Gradient Panel!"));
		this.add(new JTextField("Un champ de texte"));
	}

	public void setColor1(Color c1) {
		this.color1 = c1;
		repaint();
	}

	public void setColor2(Color c2) {
		this.color2 = c2;
		repaint();
	}
	
	public void paint(Graphics g){
		super.paint(g);
		//
	}

	protected void paintComponent(Graphics g) {
		Graphics2D g2 = (Graphics2D) g;
		super.paintComponent(g);
		int w = getWidth();
		int h = getHeight();

		GradientPaint gradient = new GradientPaint(0, 0, color1, w, h, color2, true);
		g2.setPaint(gradient);
		g2.fillRect(0, 0, w, h);
		repaint();
	}
}

package panelDegrade;

import java.awt.Color;
import java.awt.Component;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.DefaultComboBoxModel;
import javax.swing.JComboBox;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.ListCellRenderer;

public class ColorChoicePanel extends JPanel implements ListCellRenderer {
	private MainView view;

	private JComboBox jcb_color_1;

	private JComboBox jcb_color_2;

	public ColorChoicePanel(MainView view) {
		super();
		this.view = view;
		initialize();
	}

	private void initialize() {
		GradientColor[] colors = { new GradientColor("Noir", 0, 0, 0), new GradientColor("Blanc", 255, 255, 255),
				new GradientColor("Rouge", 255, 0, 0), new GradientColor("Vert", 0, 255, 0), new GradientColor("Bleu", 0, 0, 255) };
		DefaultComboBoxModel dcbm_colors_1 = new DefaultComboBoxModel(colors);
		DefaultComboBoxModel dcbm_colors_2 = new DefaultComboBoxModel(colors);
		jcb_color_1 = new JComboBox(dcbm_colors_1);
		jcb_color_1.setRenderer(this);
		jcb_color_1.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				JComboBox combo = (JComboBox) e.getSource();
				Color c = (Color) combo.getSelectedItem();
				view.setColor1(c);
			}
		});

		jcb_color_2 = new JComboBox(dcbm_colors_2);
		jcb_color_2.setRenderer(this);
		jcb_color_2.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				JComboBox combo = (JComboBox) e.getSource();
				Color c = (Color) combo.getSelectedItem();
				view.setColor2(c);
			}
		});
		

		add(jcb_color_1);
		add(jcb_color_2);
	}

	class GradientColor extends Color {
		private String colorName;

		public GradientColor(String colorName, int r, int g, int b) {
			super(r, g, b);
			this.colorName = colorName;
		}

		public String toString() {
			return colorName;
		}
	}

	public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected, boolean cellHasFocus) {
		JLabel label = null;
		if (value instanceof GradientColor) {
			GradientColor gradientColor = (GradientColor) value;
			label = new JLabel();
			label.setText(gradientColor.toString());
			label.setForeground(gradientColor);
			list.add(label);
		}
		return label;
	}
}

package panelDegrade;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.GradientPaint;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;

public class GradientPanel extends JPanel {

	private Color color1;

	private Color color2;

	public GradientPanel() {
		this(Color.blue, Color.green);
	}

	public GradientPanel(Color c1, Color c2) {
		super();
		this.color1 = c1;
		this.color2 = c2;
	}

	public void setColor1(Color c1) {
		this.color1 = c1;
		repaint();
	}

	public void setColor2(Color c2) {
		this.color2 = c2;
		repaint();
	}

	// Overloaded in order to paint the background
	protected void paintComponent(Graphics g) {
		Graphics2D g2 = (Graphics2D) g;

		int w = getWidth();
		int h = getHeight();

		GradientPaint gradient = new GradientPaint(0, 0, color1, w, h, color2, true);
		g2.setPaint(gradient);
		g2.fillRect(0, 0, w, h);
	}

	public static void main(String[] args) {

		final GradientPanel pGradient = new GradientPanel();

		Color[] colors = { createColor("Black", Color.black), createColor("Blue", Color.blue), createColor("Green", Color.green),
				createColor("yellow", Color.yellow), createColor("orange", Color.orange), createColor("red", Color.red),
				createColor("white", Color.white) };

		JComboBox c1 = new JComboBox(colors);
		c1.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				JComboBox combo = (JComboBox) e.getSource();
				Color c = (Color) combo.getSelectedItem();
				pGradient.setColor1(c);
			}
		});

		JComboBox c2 = new JComboBox(colors);
		c2.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				JComboBox combo = (JComboBox) e.getSource();
				Color c = (Color) combo.getSelectedItem();
				pGradient.setColor2(c);
			}
		});

		JPanel pColors = new JPanel(new GridLayout(0, 2));
		pColors.add(c1);
		pColors.add(c2);

		pGradient.add(new JButton("A button"));
		pGradient.add(new JTextField("A text field"));

		c1.setSelectedItem(colors[1]);
		c2.setSelectedItem(colors[2]);

		JFrame f = new JFrame("Gradient test");
		f.setSize(300, 200);
		f.getContentPane().add(pColors, BorderLayout.NORTH);
		f.getContentPane().add(pGradient, BorderLayout.CENTER);
		f.setVisible(true);
	}

	private static Color createColor(String name, Color c) {

		final String colorname = name;
		Color color = new Color(c.getRed(), c.getGreen(), c.getBlue()) {
			private String name = colorname;

			public String toString() {
				return name;
			}
		};
		return color;
	}
}