fscolor.java

利用opensource的开源jar实现生成flash文件

/*
 * FSColor.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;

/**
FSColor is used to represent colours. 
 
<p>The FSColor class supports the RGB colour space with an optional alpha channel which is used to specify the transparency of an object. An FSColor object supports 32-bit colours with 8 bits per colour channel.</p>

<table class="datasheet">

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

<tr>
<td><a name="FSColor_0">red</a></td>
<td>The red channel of the colour, with values in the range 0..255.</td>
</tr>

<tr>
<td><a name="FSColor_1">green</a></td>
<td>The green channel of the colour, with values in the range 0..255.</td>
</tr>

<tr>
<td><a name="FSColor_2">blue</a></td>
<td>The blue channel of the colour, with values in the range 0..255.</td>
</tr>

<tr>
<td><a name="FSColor_3">alpha</a></td>
<td>The alpha channel of the colour, with values in the range 0..255.</td>
</tr>

</table>

<p>Whether a colour contains transparency information is determined by the context created by the object that contains the colour. For example colours within the FSDefineShape and FSDefineShape2 objects do not contain alpha channel information while those in an FSDefineShape3 object do. To simplify the use of the colours only a single class is provided. The alpha channel can be ignored if not required within the object the colour is defined for. When a FSColor object is encoded or decoded the object notifies the colour objects it contains whether the alpha channel information should also be encoded or decoded. As of Version 5 of the Macromedia Flash (SWF) File Format Specification only the FSPlaceObject2, FSDefineText2 and FSDefineShape3 classes use colours containing an alpha channel.</p>

<p>The class provides a range of constructors to instantiate objects using colour information presented in a variety of formats. To create a colour, specifying values for colour channels in the following order: red, green, blue and optionally alpha:</p>

<pre>
FSColor red = new FSColor(255, 0, 0);
FSColor green = new FSColor(0, 255, 0);
FSColor blue = new FSColor(0, 0, 255);
</pre>

<p>When the alpha channel is not specified it defaults to a value of 255 which defines the colour to be completely opaque. For transparent colours the alpha channel determines how opaque the colour is. 0 represents a fully transparent colour and 255 is fully opaque.</p>

<pre>
FSColor transparentRed = new FSColor(255, 0, 0, 128);
FSColor transparentGreen = new FSColor(0, 255, 0, 128);
FSColor transparentBlue = new FSColor(0, 0, 255, 128);
</pre>

<p>When the alpha channel is not specified it defaults to a value of 255 which defines the colour to be completely opaque. The classes that contain colour objects control whether the value for the alpha channel is encoded. For example FSDefineShape and FSDefineShape2 support opaque colours while FSDefineShape3 supports transparent colours. If only opaque colours are supported then the alpha channel can be ignored when creating and manipulating FSColor objects.</p>

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

<p>FSColor class represents the colour data types, RGB and RGBA in the Macromedia Flash (SWF) File Format Specification. The colour data structure was available was introduced in Flash 1 and transparent colours were introduced in Flash 3.</p>
 */
public class FSColor extends FSTransformObject
{
    private int red = 0;
    private int green = 0;
    private int blue = 0;
    private int alpha = 255;

    /**
     * Construct an FSColor object and initialize it with values decoded from 
     * a binary encoded FSColor object.
     * 
     * @param coder an FSCoder object containing an FSColor encoded as binary
     * data.
     */
    public FSColor(FSCoder coder)
    {
        decode(coder);
    }    
    /** 
     * Constructs an FSColor object containing red, green and blue channels. The
     * alpha channel defaults to the value 255 - defining an opaque colour.
     * 
     * @param r value for the red channel, in the range 0..255.
       @param g value for the green channel, in the range 0..255.
       @param b value for the blue channel, in the range 0..255.
        */     
    public FSColor(int r, int g, int b)
    {
        setRed(r);
        setGreen(g);
        setBlue(b);
    }

    /** Constructs an FSColor object containing red, green, blue and alpha channels.
     
        @param r value for the red channel, in the range 0..255.
        @param g value for the green channel, in the range 0..255.
        @param b value for the blue channel, in the range 0..255.
        @param a value for the alpha channel, in the range 0..255.
     */
    public FSColor(int r, int g, int b, int a)
    {
        setRed(r);
        setGreen(g);
        setBlue(b);
        setAlpha(a);
    }
    /**
     * Construct an FSColor object and initialize it with value from another 
     * FSColor object.
     * 
     * @param obj an FSColor object.
     */
    public FSColor(FSColor obj)
    {
        red = obj.red;
        green = obj.green;
        blue = obj.blue;
        alpha = obj.alpha;
    }

    /** Gets the value for the red colour channel. 

        @return the value for the red channel in the range 0..255.
        */    
    public int getRed() { return red; }

    /** Gets the value for the green colour channel. 

        @return the value for the green channel in the range 0..255.
        */    
    public int getGreen() { return green; }

    /** Gets the value for the blue colour channel. 

        @return the value for the blue channel in the range 0..255.
        */
    public int getBlue() { return blue; }

    /** Gets the value for the alpha colour channel. 

        @return the value for the alpha channel in the range 0..255.
        */
    public int getAlpha() { return alpha; }

    /** Set the value for the red colour channel. 

        @param r value for the red channel.
        */    
    public void setRed(int r)
    {
        red = r;
    }

    /** Set the value for the green colour channel.

        @param g value for the green channel.
        */
    public void setGreen(int g)
    {
        green = g;
    }

    /** Set the value for the blue colour channel.

       @param b value for the blue channel, in the range 0..255.
     */
    public void setBlue(int b) 
    {
        blue = b;
    }

    /** Set the value for the alpha channel.

        @param a value for the alpha channel, in the range 0..255.
    */
    public void setAlpha(int a)
    {
        alpha = a;
    }

    /** Set the values for the red, green and blue colour channels. The alpha 
     * channel is not changed.

        @param r value for the red channel, in the range 0..255.
        @param g value for the green channel, in the range 0..255.
        @param b value for the blue channel, in the range 0..255.
        */
    public void setChannels(int r, int g, int b)
    {
        setRed(r);
        setGreen(g);
        setBlue(b);
    }
    
    /** Set the values for each of the four colour channels.
    
        @param r value for the red channel, in the range 0..255.
        @param g value for the green channel, in the range 0..255.
        @param b value for the blue channel, in the range 0..255.
        @param a value for the alpha channel, in the range 0..255.
        */
    public void setChannels(int r, int g, int b, int a)
    {
        setRed(r);
        setGreen(g);
        setBlue(b);
        setAlpha(a);
    }

    /** 
     * 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))
        {
            FSColor typedObject = (FSColor)anObject;
            
            result = red == typedObject.red;
            result = result && green == typedObject.green;
            result = result && blue == typedObject.blue;
            result = result && alpha == typedObject.alpha;
        }
        return result;
    }

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

        if (depth > 0)
        {
            buffer.append(": { ");
            Transform.append(buffer, "red", red);
            Transform.append(buffer, "green", green);
            Transform.append(buffer, "blue", blue);
            Transform.append(buffer, "alpha", alpha);
            buffer.append("}");
        }
    }

    public int length(FSCoder coder)
    {
        return (coder.context[FSCoder.TransparentColors] != 0) ? 4 : 3;
    }
    
    public void encode(FSCoder coder)
    {
        coder.writeWord(red, 1);
        coder.writeWord(green, 1);
        coder.writeWord(blue, 1);
    
        if (coder.context[FSCoder.TransparentColors] != 0)
            coder.writeWord(alpha, 1);
    }
    
    public void decode(FSCoder coder)
    {
        red = coder.readWord(1, false);
        green = coder.readWord(1, false);
        blue = coder.readWord(1, false);
        
        if (coder.context[FSCoder.TransparentColors] != 0)
            alpha = coder.readWord(1, false);
    }
}