// TGradientPaint.java

import javax.swing.*;
import javax.swing.event.*;
import javax.swing.border.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;

class TGradientPaint extends JFrame {
    DisplayCanvas canvas;
    String[] colorLabels = {"White", "Red", "Blue", "Green", "Yellow", 
                            "Magenta", "Light Gray", "Black"};
    JRadioButton acyclicButton, cyclicButton;

    public TGradientPaint() {
        // 1. Assign a title to the frame and get a handle on
        // the frame's content pane
        super("TGradientPaint");
        Container container = getContentPane();

        // 2. Add the canvas with rectangles
        canvas = new DisplayCanvas();
        container.add(canvas);

        // 3. Create a control panel with titled border
        JPanel panel = new JPanel();
        TitledBorder border = new TitledBorder(
          "Select a Fill Mode, and Double Click Mouse"
          + " at Two Points with Different Colors...");
        panel.setBorder(border);

        // 4. Create a combo box and the necessary radio buttons
        JComboBox comboBox = new JComboBox(colorLabels);
        comboBox.addActionListener(new ComboBoxListener());

        acyclicButton = new JRadioButton("Acyclic", true);
        acyclicButton.addActionListener(new RadioButtonListener());
        cyclicButton = new JRadioButton("Cyclic");
        cyclicButton.addActionListener(new RadioButtonListener());
        ButtonGroup group = new ButtonGroup();
        group.add(acyclicButton);
        group.add(cyclicButton);

        // 5. Add the combo box, and radio buttons to the panel
        panel.add(comboBox);
        panel.add(acyclicButton);
        panel.add(cyclicButton);

        // 6. Add the panel to the frame
        container.add(BorderLayout.SOUTH, panel);

        // 7. Add a frame closing listener and display the frame
        addWindowListener(new WindowEventHandler());
        pack(); // Packs around the contents with suitable size
        show(); // Display the frame
    }

    // 8. Code to handle closing of the frame
    class WindowEventHandler extends WindowAdapter {
        public void windowClosing(WindowEvent e) {
            System.exit(0);
        }
    }

    // 9. The main method...
    public static void main(String arg[]) {
        new TGradientPaint();
    }

    // 10. Canvas to draw round-cornered rectangles
    class DisplayCanvas extends Canvas {
        // 11. Points and Colors for the gradient patterns
        Point2D point1, point2;

        Color fillColor = Color.black;
        Color[] colors = {Color.white, Color.red, Color.blue, Color.green,
                          Color.yellow, Color.magenta, Color.lightGray,
                          Color.black};
        Color fillColor1, fillColor2;

        boolean cyclicMode = false;
        
        // Constructor
        DisplayCanvas() {
            // 12. Add the mouse listener to receive a rectangle selection
            addMouseListener(new MyMouseListener());
            setBackground(Color.white);  // For canvas background color
            setSize(400, 225);  // Canvas width=400 height=225
        }

        
        public void paint(Graphics g) {
            // 13. Create the graphics context object
            Graphics2D g2D = (Graphics2D) g;

            if (point1 != null && point2 == null)
               drawHighlightSquare(g2D, fillColor, point1);

            if (point1 != null && point2 != null) {
               Paint gp = new GradientPaint(point1, fillColor1,
                                            point2, fillColor2,
                                            cyclicMode);
               g2D.setPaint(gp);
               g2D.fill(new Rectangle2D.Double(0, 0, getWidth(), getHeight()));
            }
        }

        public void drawHighlightSquare(Graphics2D g2D, Color c, Point2D p) {
            g2D.setColor(c);
            double x = p.getX();
            double y = p.getY();
            g2D.fill(new Rectangle.Double(x-3.0, y-3.0, 6.0, 6.0));
        }
    }

    // 14. The mouse listener to handle double clicks over the canvas. 
    class MyMouseListener extends MouseAdapter {
        int clickTime = 0;

        public void mouseClicked(MouseEvent e) {
            if (e.getClickCount() == 2) {
                if (clickTime == 0) {
                    clickTime++;
                    canvas.fillColor1 = canvas.fillColor;
                    canvas.point2 = null;
                    canvas.point1 = e.getPoint();
                    canvas.repaint();
                }
                else if (clickTime == 1) {
                    clickTime--;
                    canvas.fillColor2 = canvas.fillColor;
                    canvas.point2 = e.getPoint();
                    canvas.repaint();
                }
            }
        }
    }

    // 15. Combo box listener to handle color selections
    class ComboBoxListener implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            JComboBox cBox = (JComboBox) e.getSource();
            String color = (String) cBox.getSelectedItem();
            for (int i=0; i<colorLabels.length; i++) {
                if(color.equals(colorLabels[i])) {
                    canvas.fillColor = canvas.colors[i];
                    return;
                }
            }
        }
    }

    // 16. Radio Button listener to select different fill modes
    // such as cyclic (true) or acyclic (false).
    class RadioButtonListener implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            JRadioButton button = (JRadioButton) e.getSource();

            if (button.equals(acyclicButton)) {
                canvas.cyclicMode = false;
            }
            else if (button.equals(cyclicButton)) {
                canvas.cyclicMode = true;
            }
        }
    }
}