SquareLayout.java Source code

Introduction

Here is the source code for SquareLayout.java

Source

/**
 * The utillib library.
 * More information is available at http://www.jinchess.com/.
 * Copyright (C) 2002 Alexander Maryanovsky.
 * All rights reserved.
 *
 * The utillib library is free software; you can redistribute
 * it and/or modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * The utillib library 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 Lesser
 * General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with utillib library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

import java.awt.*;

/**
 * A LayoutManager which lays out a single component making sure its height is
 * always the same as its width. If the parent container's width differs from
 * it height, the child will be laid out according to its x and y alignment.
 */

public class SquareLayout implements LayoutManager {

    /**
     * Creates a new SquareLayout.
     */

    public SquareLayout() {

    }

    /**
     * Creates a new Container with SquareLayout which will contain the specified
     * component.
     */

    public static Container createSquareContainer(Component child) {
        Container container = new Container();
        container.setLayout(new SquareLayout());
        container.add(child);

        return container;
    }

    /**
     * Adds the specified component with the specified name to the layout. 
     */

    public void addLayoutComponent(String name, Component component) {

    }

    /**
     * Removes the specified component from the layout. 
     */

    public void removeLayoutComponent(Component component) {

    }

    /**
     * Returns the sole child of the specified container, or <code>null</code> if
     * none. Throws an <code>IllegalStateException</code> if there is more than
     * one child.
     */

    private Component getChild(Container c) {
        int childCount = c.getComponentCount();
        if (childCount > 1)
            throw new IllegalStateException("May not layout more than one component");
        else if (childCount == 0)
            return null;
        else
            return c.getComponent(childCount - 1);
    }

    /**
     * Lays out the container in the specified panel. 
     */

    public void layoutContainer(Container container) {
        Component child = getChild(container);
        if (child == null)
            return;

        Dimension parentSize = container.getSize();
        Insets insets = container.getInsets();

        // A rectangle specifying the actual area available for layout. 
        Rectangle rect = new Rectangle(insets.left, insets.top, parentSize.width - insets.left - insets.right,
                parentSize.height - insets.top - insets.bottom);

        int minSize = rect.width < rect.height ? rect.width : rect.height;
        int widthSpace = rect.width - minSize;
        int heightSpace = rect.height - minSize;
        child.setBounds(rect.x + (int) (widthSpace * child.getAlignmentX()),
                rect.y + (int) (heightSpace * child.getAlignmentY()), minSize, minSize);
    }

    /**
     * Calculates the minimum size dimensions for the specified panel given the 
     * components in the specified parent container. 
     */

    public Dimension minimumLayoutSize(Container container) {
        Component child = getChild(container);
        if (child == null)
            return new Dimension(0, 0);

        Dimension childMinSize = child.getMinimumSize();
        Insets insets = container.getInsets();

        int width = childMinSize.width + insets.left + insets.right;
        int height = childMinSize.height + insets.top + insets.bottom;
        int maxSize = Math.max(width, height);
        return new Dimension(maxSize, maxSize);
    }

    /**
     * Calculates the preferred size dimensions for the specified panel given the
     * components in the specified parent container. 
     */

    public Dimension preferredLayoutSize(Container container) {
        Component child = getChild(container);
        if (child == null)
            return new Dimension(0, 0);

        Dimension childPrefSize = child.getPreferredSize();
        Insets insets = container.getInsets();

        int width = childPrefSize.width + insets.left + insets.right;
        int height = childPrefSize.height + insets.top + insets.bottom;
        int maxSize = Math.max(width, height);
        return new Dimension(maxSize, maxSize);
    }

}