CircleLayoutTest.java Source code

Introduction

Here is the source code for CircleLayoutTest.java

Source

/*
   This program is a part of the companion code for Core Java 8th ed.
   (http://horstmann.com/corejava)
    
   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
    
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
    
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Insets;
import java.awt.LayoutManager;

import javax.swing.JButton;
import javax.swing.JFrame;

/**
 * @version 1.32 2007-06-12
 * @author Cay Horstmann
 */
public class CircleLayoutTest {
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                CircleLayoutFrame frame = new CircleLayoutFrame();
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setVisible(true);
            }
        });
    }
}

/**
 * A frame that shows buttons arranged along a circle.
 */
class CircleLayoutFrame extends JFrame {
    public CircleLayoutFrame() {
        setTitle("CircleLayoutTest");

        setLayout(new CircleLayout());
        add(new JButton("Yellow"));
        add(new JButton("Blue"));
        add(new JButton("Red"));
        add(new JButton("Green"));
        add(new JButton("Orange"));
        add(new JButton("Fuchsia"));
        add(new JButton("Indigo"));
        pack();
    }
}

/**
 * A layout manager that lays out components along a circle.
 */
class CircleLayout implements LayoutManager {
    public void addLayoutComponent(String name, Component comp) {
    }

    public void removeLayoutComponent(Component comp) {
    }

    public void setSizes(Container parent) {
        if (sizesSet)
            return;
        int n = parent.getComponentCount();

        preferredWidth = 0;
        preferredHeight = 0;
        minWidth = 0;
        minHeight = 0;
        maxComponentWidth = 0;
        maxComponentHeight = 0;

        // compute the maximum component widths and heights
        // and set the preferred size to the sum of the component sizes.
        for (int i = 0; i < n; i++) {
            Component c = parent.getComponent(i);
            if (c.isVisible()) {
                Dimension d = c.getPreferredSize();
                maxComponentWidth = Math.max(maxComponentWidth, d.width);
                maxComponentHeight = Math.max(maxComponentHeight, d.height);
                preferredWidth += d.width;
                preferredHeight += d.height;
            }
        }
        minWidth = preferredWidth / 2;
        minHeight = preferredHeight / 2;
        sizesSet = true;
    }

    public Dimension preferredLayoutSize(Container parent) {
        setSizes(parent);
        Insets insets = parent.getInsets();
        int width = preferredWidth + insets.left + insets.right;
        int height = preferredHeight + insets.top + insets.bottom;
        return new Dimension(width, height);
    }

    public Dimension minimumLayoutSize(Container parent) {
        setSizes(parent);
        Insets insets = parent.getInsets();
        int width = minWidth + insets.left + insets.right;
        int height = minHeight + insets.top + insets.bottom;
        return new Dimension(width, height);
    }

    public void layoutContainer(Container parent) {
        setSizes(parent);

        // compute center of the circle

        Insets insets = parent.getInsets();
        int containerWidth = parent.getSize().width - insets.left - insets.right;
        int containerHeight = parent.getSize().height - insets.top - insets.bottom;

        int xcenter = insets.left + containerWidth / 2;
        int ycenter = insets.top + containerHeight / 2;

        // compute radius of the circle

        int xradius = (containerWidth - maxComponentWidth) / 2;
        int yradius = (containerHeight - maxComponentHeight) / 2;
        int radius = Math.min(xradius, yradius);

        // lay out components along the circle

        int n = parent.getComponentCount();
        for (int i = 0; i < n; i++) {
            Component c = parent.getComponent(i);
            if (c.isVisible()) {
                double angle = 2 * Math.PI * i / n;

                // center point of component
                int x = xcenter + (int) (Math.cos(angle) * radius);
                int y = ycenter + (int) (Math.sin(angle) * radius);

                // move component so that its center is (x, y)
                // and its size is its preferred size
                Dimension d = c.getPreferredSize();
                c.setBounds(x - d.width / 2, y - d.height / 2, d.width, d.height);
            }
        }
    }

    private int minWidth = 0;
    private int minHeight = 0;
    private int preferredWidth = 0;
    private int preferredHeight = 0;
    private boolean sizesSet = false;
    private int maxComponentWidth = 0;
    private int maxComponentHeight = 0;
}