absolutelayout.java

java平台的图形音乐播放器

/*
 * AbsoluteLayout.
 * 
 * JavaZOOM : [e-mail]
 *            http://www.javazoom.net
 *
 *-----------------------------------------------------------------------
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Library General Public License as published
 *   by the Free Software Foundation; either version 2 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 Library General Public License for more details.
 *
 *   You should have received a copy of the GNU Library General Public
 *   License along with this program; if not, write to the Free Software
 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *----------------------------------------------------------------------
 */
package javazoom.jlgui.player.amp.skin;

import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.LayoutManager;
import java.awt.LayoutManager2;

/**
 * AbsoluteLayout is a LayoutManager that works as a replacement for "null" layout to
 * allow placement of components in absolute positions.
 */
public class AbsoluteLayout implements LayoutManager2, java.io.Serializable
{
    /**
     * generated Serialized Version UID
     */
    static final long serialVersionUID = -1919857869177070440L;

    /**
     * Adds the specified component with the specified name to
     * the layout.
     *
     * @param name the component name
     * @param comp the component to be added
     */
    public void addLayoutComponent(String name, Component comp)
    {
        throw new IllegalArgumentException();
    }

    /**
     * Removes the specified component from the layout.
     *
     * @param comp the component to be removed
     */
    public void removeLayoutComponent(Component comp)
    {
        constraints.remove(comp);
    }

    /**
     * Calculates the preferred dimension for the specified
     * panel given the components in the specified parent container.
     *
     * @param parent the component to be laid out
     * @see #minimumLayoutSize
     */
    public Dimension preferredLayoutSize(Container parent)
    {
        int maxWidth = 0;
        int maxHeight = 0;
        for (java.util.Enumeration e = constraints.keys(); e.hasMoreElements();)
        {
            Component comp = (Component) e.nextElement();
            AbsoluteConstraints ac = (AbsoluteConstraints) constraints.get(comp);
            Dimension size = comp.getPreferredSize();
            int width = ac.getWidth();
            if (width == -1) width = size.width;
            int height = ac.getHeight();
            if (height == -1) height = size.height;
            if (ac.x + width > maxWidth) maxWidth = ac.x + width;
            if (ac.y + height > maxHeight) maxHeight = ac.y + height;
        }
        return new Dimension(maxWidth, maxHeight);
    }

    /**
     * Calculates the minimum dimension for the specified
     * panel given the components in the specified parent container.
     *
     * @param parent the component to be laid out
     * @see #preferredLayoutSize
     */
    public Dimension minimumLayoutSize(Container parent)
    {
        int maxWidth = 0;
        int maxHeight = 0;
        for (java.util.Enumeration e = constraints.keys(); e.hasMoreElements();)
        {
            Component comp = (Component) e.nextElement();
            AbsoluteConstraints ac = (AbsoluteConstraints) constraints.get(comp);
            Dimension size = comp.getMinimumSize();
            int width = ac.getWidth();
            if (width == -1) width = size.width;
            int height = ac.getHeight();
            if (height == -1) height = size.height;
            if (ac.x + width > maxWidth) maxWidth = ac.x + width;
            if (ac.y + height > maxHeight) maxHeight = ac.y + height;
        }
        return new Dimension(maxWidth, maxHeight);
    }

    /**
     * Lays out the container in the specified panel.
     *
     * @param parent the component which needs to be laid out
     */
    public void layoutContainer(Container parent)
    {
        for (java.util.Enumeration e = constraints.keys(); e.hasMoreElements();)
        {
            Component comp = (Component) e.nextElement();
            AbsoluteConstraints ac = (AbsoluteConstraints) constraints.get(comp);
            Dimension size = comp.getPreferredSize();
            int width = ac.getWidth();
            if (width == -1) width = size.width;
            int height = ac.getHeight();
            if (height == -1) height = size.height;
            comp.setBounds(ac.x, ac.y, width, height);
        }
    }

    /**
     * Adds the specified component to the layout, using the specified
     * constraint object.
     *
     * @param comp   the component to be added
     * @param constr where/how the component is added to the layout.
     */
    public void addLayoutComponent(Component comp, Object constr)
    {
        if (!(constr instanceof AbsoluteConstraints)) throw new IllegalArgumentException();
        constraints.put(comp, constr);
    }

    /**
     * Returns the maximum size of this component.
     *
     * @see java.awt.Component#getMinimumSize()
     * @see java.awt.Component#getPreferredSize()
     * @see LayoutManager
     */
    public Dimension maximumLayoutSize(Container target)
    {
        return new Dimension(Integer.MAX_VALUE, Integer.MAX_VALUE);
    }

    /**
     * Returns the alignment along the x axis.  This specifies how
     * the component would like to be aligned relative to other
     * components.  The value should be a number between 0 and 1
     * where 0 represents alignment along the origin, 1 is aligned
     * the furthest away from the origin, 0.5 is centered, etc.
     */
    public float getLayoutAlignmentX(Container target)
    {
        return 0;
    }

    /**
     * Returns the alignment along the y axis.  This specifies how
     * the component would like to be aligned relative to other
     * components.  The value should be a number between 0 and 1
     * where 0 represents alignment along the origin, 1 is aligned
     * the furthest away from the origin, 0.5 is centered, etc.
     */
    public float getLayoutAlignmentY(Container target)
    {
        return 0;
    }

    /**
     * Invalidates the layout, indicating that if the layout manager
     * has cached information it should be discarded.
     */
    public void invalidateLayout(Container target)
    {
    }
    /**
     * A mapping <Component, AbsoluteConstraints>
     */
    protected java.util.Hashtable constraints = new java.util.Hashtable();
}