controlcurve.java

java平台的图形音乐播放器

/*
 * ControlCurve.
 * 
 * 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.equalizer.ui;

import java.awt.Polygon;

public abstract class ControlCurve
{
    static final int EPSILON = 36; /* square of distance for picking */
    protected Polygon pts;
    protected int selection = -1;
    int maxHeight = -1;
    int minHeight = -1;

    public ControlCurve()
    {
        pts = new Polygon();
    }

    public int boundY(int y)
    {
        int ny = y;
        if ((minHeight >= 0) && (y < minHeight))
        {
            ny = 0;
        }
        if ((maxHeight >= 0) && (y >= maxHeight))
        {
            ny = maxHeight - 1;
        }
        return ny;
    }

    public void setMaxHeight(int h)
    {
        maxHeight = h;
    }

    public void setMinHeight(int h)
    {
        minHeight = h;
    }

    /**
     * Return index of control point near to (x,y) or -1 if nothing near.
     * @param x
     * @param y
     * @return
     */
    public int selectPoint(int x, int y)
    {
        int mind = Integer.MAX_VALUE;
        selection = -1;
        for (int i = 0; i < pts.npoints; i++)
        {
            int d = sqr(pts.xpoints[i] - x) + sqr(pts.ypoints[i] - y);
            if (d < mind && d < EPSILON)
            {
                mind = d;
                selection = i;
            }
        }
        return selection;
    }

    /**
     * Square of an int.
     * @param x
     * @return
     */
    static int sqr(int x)
    {
        return x * x;
    }

    /**
     * Add a control point, return index of new control point.
     * @param x
     * @param y
     * @return
     */
    public int addPoint(int x, int y)
    {
        pts.addPoint(x, y);
        return selection = pts.npoints - 1;
    }

    /**
     * Set selected control point.
     * @param x
     * @param y
     */
    public void setPoint(int x, int y)
    {
        if (selection >= 0)
        {
            pts.xpoints[selection] = x;
            pts.ypoints[selection] = y;
        }
    }

    /**
     * Remove selected control point.
     */
    public void removePoint()
    {
        if (selection >= 0)
        {
            pts.npoints--;
            for (int i = selection; i < pts.npoints; i++)
            {
                pts.xpoints[i] = pts.xpoints[i + 1];
                pts.ypoints[i] = pts.ypoints[i + 1];
            }
        }
    }

    public abstract Polygon getPolyline();
}