fsdefinejpegimage2.java

利用opensource的开源jar实现生成flash文件

/*
 * FSDefineJPEGImage2.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;

/**
FSDefineJPEGImage2 is used to define a JPEG encoded image with an integrated 
encoding table. 
  
<p>It extends the FSDefineJPEGImage class by including a separate encoding table, 
rather than using an FSJPEGEncodingTable object to store the encoding table. 
This allows multiple JPEG images with different amounts of compression to be 
included within a Flash file.</p>

<table class="datasheet">

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

<tr><td><a name="FSDefineJPEGImage2_0">type</a></td>
<td>Identifies the data structure when it is encoded. Read-only.</td>
</tr>

<tr>
<td><a name="FSDefineJPEGImage2_1">identifier</a></td>
<td>A unique identifier, in the range 1..65535, that is used to reference the 
image from other objects.</td>
</tr>

<tr>
<td><a name="FSDefineJPEGImage2_2">image</a></td>
<td>An array of bytes containing the JPEG compressed image.</td>
</tr>

<tr>
<td><a name="FSDefineJPEGImage2_3">encodingTable</a></td>
<td>An array of bytes containing the encoding table. May be set to null.</td>
</tr>
</table>

<p>Although the encoding table defines how the image is compressed it is not 
essential. If an FSDefineJPEGImage3 object is created with an empty encoding 
table then the Flash Player will still display the JPEG image correctly. The 
empty encoding table is not a null object. It contains four bytes: 0xFF, 0xD8, 
0xFF, 0xD9. For convenience passing a null reference to any of the constructors 
or to the setEncodingTable method will create an empty table.</p>

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

<p>The simplest way to use the FSDefineJPEGImage2 class is to use the constructor 
that specifies the JPEG file to initialise the object:</p>

<pre>
File aFile = new File(filename);
byte[] bytes = new byte[(int)aFile.length()];

try {
    FileInputStream imageContents = new FileInputStream(aFile);            
    imageContents.read(bytes);
    imageContents.close();
}
catch (FileNotFoundException e) {
    throw new FileNotFoundException(filename);
}
catch (IOException e) {
    throw new IOException(filename);
}

movie.add(new FSDefineJPEGImage2(movie.newIdentifier(), bytes));
</pre>

<p>This generates an object with an empty encoding table, however the image will still be displayed correctly.</p>

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

<p>The FSDefineJPEGImage2 class represents the DefineBitsJPEG2 tag from the Macromedia Flash (SWF) File Format Specification. It was introduced in Flash 2.</p>
 */
public class FSDefineJPEGImage2 extends FSDefineObject
{
    private byte[] image = null;
    private byte[] encodingTable = null;

    /**
     * Construct an FSDefineJPEGImage2 object, initalizing it with values decoded 
     * from an encoded object.
     * 
     * @param coder an FSCoder containing the binary data.
     */
    public FSDefineJPEGImage2(FSCoder coder)
    {
        super(DefineJPEGImage2, 0);
        decode(coder);
    }
    /** Constructs an FSDefineJPEGImage2 object with the identifier, JPEG image data and JPEG encoding table data.

        @param anIdentifier    the unique identifier for this object
        @param imageBytes the JPEG encoded image data.
        @param encodingBytes the JPEG encoded encoding table.
        */
    public FSDefineJPEGImage2(int anIdentifier, byte[] imageBytes, byte[] encodingBytes)
    {
        super(DefineJPEGImage2, anIdentifier);
        setImage(imageBytes);
        setEncodingTable(encodingBytes);
    }
    /** Constructs an FSDefineJPEGImage2 object with the identifier, JPEG image data and JPEG encoding table data.

        @param anIdentifier    the unique identifier for this object
        @param imageBytes the JPEG encoded image data.
        */
    public FSDefineJPEGImage2(int anIdentifier, byte[] imageBytes)
    {
        super(DefineJPEGImage2, anIdentifier);
        setImage(imageBytes);
        setEncodingTable(null);
    }
    /**
     * Constructs an FSDefineJPEGImage2 object by copying values from an 
     * existing object.
     *
     * @param obj an FSDefineJPEGImage2 object.
     */
    public FSDefineJPEGImage2(FSDefineJPEGImage2 obj)
    {
        super(obj);
        image = Transform.clone(obj.image);
        encodingTable = Transform.clone(obj.encodingTable);
    }

    /** Gets the image data.

        @return the array of bytes containing the image data.
        */
    public byte[] getImage() { return image; }

    /** Gets the encoding table.

        @return the array of bytes containing the encoding table.
        */
    public byte[] getEncodingTable()  { return encodingTable; }

    /** Sets the image data.

        @param bytes an array of bytes containing the image data.
        */
    public void setImage(byte[] bytes)
    {
        image = bytes;
    }

    /** Sets the encoding table.

        @param bytes an array of bytes containing the encoding table.
        */
    public void setEncodingTable(byte[] bytes)
    {
        if (bytes == null) {
            bytes = new byte[] { (byte)0xFF, (byte)0xD8, (byte)0xFF, (byte)0xD9 };
        }
        encodingTable = bytes;
    }

    public Object clone()
    {
        FSDefineJPEGImage2 anObject = (FSDefineJPEGImage2)super.clone();
        
        anObject.image = Transform.clone(image);
        anObject.encodingTable = Transform.clone(encodingTable);
        
        return anObject;
    }

    public boolean equals(Object anObject)
    {
        boolean result = false;
        
        if (super.equals(anObject))
        {
            FSDefineJPEGImage2 typedObject = (FSDefineJPEGImage2)anObject;
            
            result = Transform.equals(image, typedObject.image);
            result = result && Transform.equals(encodingTable, typedObject.encodingTable);
        }
        return result;
    }

    public void appendDescription(StringBuffer buffer, int depth)
    {
        buffer.append(name());
        
        if (depth > 0)
        {
            buffer.append(": { ");
            Transform.append(buffer, "encodingTable", "<data>");
            Transform.append(buffer, "image", "<data>");
            buffer.append("}");
        }
    }

    public int length(FSCoder coder)
    {
        super.length(coder);
        
        length += encodingTable.length;
        length += image.length;

        return length;
    }
    
    public void encode(FSCoder coder)
    {
        super.encode(coder);
        coder.writeBytes(encodingTable);
        coder.writeBytes(image);
        coder.endObject(name());
    }
    
    public void decode(FSCoder coder)
    {        
        super.decode(coder);
        setEncodingTable(readJPEGStream(coder));
        byte[] data = new byte[length-encodingTable.length-2];
        coder.readBytes(data);
        setImage(data);
        coder.endObject(name());
    }
    
    private byte[] readJPEGStream(FSCoder coder)
    {
        byte bytes[] = null;

        int soi = 0xFFD8;
        int eoi = 0xFFD9;
        
        int start = coder.getPointer();
        int end = start + ((length-2) << 3);
        
        int word = 0;
 
        do {
            word = coder.scanBits(16, false);
            
            if (word == soi) 
            {
                start = coder.getPointer();
            }
            else if (word == eoi) 
            {
                end = coder.getPointer()+16;
                break;
            }
            coder.adjustPointer(8);
        } 
        while (coder.getPointer() < end);
            
        int len = (end-start) >>> 3; 
        
        coder.setPointer(start);
        bytes = new byte[len];
        coder.readBytes(bytes);

        return bytes;
    }
}