A layout manager that lays out components along a circle
/*
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;
}
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