fsenvelope.java

利用opensource的开源jar实现生成flash文件

/*
 * FSEnvelope.java
 * Transform
 * 
 * Copyright (c) 2001-2006 Flagstone Software Ltd. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, 
 * are permitted provided that the following conditions are met:
 *
 *  * Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright notice, 
 *    this list of conditions and the following disclaimer in the documentation 
 *    and/or other materials provided with the distribution.
 *  * Neither the name of Flagstone Software Ltd. nor the names of its contributors 
 *    may be used to endorse or promote products derived from this software 
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
 * IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE 
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package com.flagstone.transform;

import java.util.ArrayList;
import java.util.Iterator;

/**
FSEnvelope is used to define an envelope which controls how a particular sound is 
played over time. 
 
<p>Each FSEnvelope object defines a point in the envelope. The FSSound object contains an array of FSEnvelope objects which define the complete envelope.</p>

<table class="datasheet">

<tr><th align="left" colspan="2">Attributes</th></tr>

<tr>
<td><a name="FSEnvelope_0">mark</a></td>
<td>The location in the playback sound data stream where the following level information applies.</td>
</tr>

<tr>
<td><a name="FSEnvelope_1">left</a></td>
<td>The sound level for the left channel, in the range 0..65535.</td>
</tr>

<tr>
<td><a name="FSEnvelope_2">right</a></td>
<td>The sound level for the right channel, in the range 0..65535..</td>
</tr>
</table>

<p>The Flash Player plays sounds at a fixed rate of 44.1KHz, therefore sounds sampled at a lower frequency are interpolated with each sample repeated to generated the 44.1Khz playback rate. For example each sample in a sound sampled at 22KHz is played twice to generated the 44.1Khz playback rate.</p>

<p>The envelope defines the sample number (and hence the time) in the playback data stream where the level information applies and <b>not</b> the sample number in the original sound data. For example to set the level 0.1 seconds into a sound that plays for 1 second the value for the mark attribute in the envelope object would be 44100 * 0.1/1.0 = 4410.</p>

<h1 class="datasheet">History</h1>

<p>The FSEnvelope class represents the SoundEnvelope structure from the Macromedia Flash (SWF) File Format Specification. It was introduced in Flash 1.</p>
 */
public class FSEnvelope extends FSTransformObject
{
    private int mark = 0;
    private int left = 0;
    private int right = 0;

    /**
     * Construct an FSEnvelope object, initalizing it with values decoded from
     * an encoded object.
     * 
     * @param coder an FSCoder containing the binary data.
     */
    public FSEnvelope(FSCoder coder)
    {
        decode(coder);
    }
    /** Constructs an envelope specifying the mark, left and right values.

        @param markValue the sample number in the 44.1KHz playback data stream where the levels for the channels is applied.
        @param leftValue the level for the left sound channel, in the range 0..65535.
        @param rightValue the level for the right sound channel, in the range 0..65535.
        */
    public FSEnvelope(int markValue, int leftValue, int rightValue)
    {
        setMark(markValue);
        setLeft(leftValue);
        setRight(rightValue);
    }
    /**
     * Constructs an FSEnvelope object by copying values from an existing 
     * object.
     *
     * @param obj an FSEnvelope object.
     */
    public FSEnvelope(FSEnvelope obj)
    {
        mark = obj.mark;
        left = obj.left;
        right = obj.right;
    }    

    /** Gets the sample number in the 44.1KHz playback data stream where the level information is applied.

        @return the mark value.
        */
    public int getMark()  { return mark; }

    /** Gets the level of the sound played in the left channel.

        @return the left value.
        */
    public int getLeft()  { return left; }

    /** Gets the level of the sound played in the right channel.

        @return the right value.
        */
    public int getRight()  { return right; }

    /** Sets the sample number in the 44.1KHz playback data stream where the levels for the channels is applied.

        @param aNumber the mark value.
        */
    public void setMark(int aNumber)
    {
        mark = aNumber;
    }

    /** Sets the level for the left sound channel.

        @param leftValue the level for the left sound channel.
        */
    public void setLeft(int leftValue)
    {
        left = leftValue;
    }

    /** Sets the level for the right sound channel.

        @param rightValue the level for the right sound channel.
        */
    public void setRight(int rightValue)
    {
        right = rightValue;
    }

    /** 
     * Returns true if anObject is equal to this one. Objects are considered 
     * equal if they would generate identical binary data when they are encoded 
     * to a Flash file.
     *
     * @return true if this object would be identical to anObject when encoded.
     */
    public boolean equals(Object anObject)
    {
        boolean result = false;
        
        if (super.equals(anObject))
        {
            FSEnvelope typedObject = (FSEnvelope)anObject;
            
            result = mark == typedObject.mark;
            result = result && left == typedObject.left;
            result = result && right == typedObject.right;
        }
        return result;
    }

    public void appendDescription(StringBuffer buffer, int depth)
    {
        buffer.append(name());

        if (depth > 0)
        {
            buffer.append(name() + ": {");
            Transform.append(buffer, "mark", mark);
            Transform.append(buffer, "left", left);
            Transform.append(buffer, "right", right);
            buffer.append("}");
        }
    }

    public int length(FSCoder coder)
    {
        int length = 8;
        return length;
    }
    
    public void encode(FSCoder coder)
    {
        coder.writeWord(mark, 4);
        coder.writeWord(left, 2);
        coder.writeWord(right, 2);
    }
    
    public void decode(FSCoder coder)
    {
        mark = coder.readWord(4, false);
        left = coder.readWord(2, false);
        right = coder.readWord(2, false);
    }
}