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java.lang.Objectcom.flagstone.transform.FSTransformObject
com.flagstone.transform.FSMovieObject
com.flagstone.transform.FSDefineObject
com.flagstone.transform.FSDefineJPEGImage3
public class FSDefineJPEGImage3
FSDefineJPEGImage3 is used to define a transparent JPEG encoded image.
It extends the FSDefineJPEGImage3 class by including a separate zlib compressed table of alpha channel values. This allows the transparency of existing JPEG encoded images to be changed without re-encoding the original image.
Attributes | |
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type | Identifies the data structure when it is encoded. The type attribute is read-only and may be used when iterating through the objects in an FSMovie object to identify the object class without using run-time type checking. |
identifier | A unique identifier, in the range 1..65535, that is used to reference the image from other objects. |
image | An array of bytes containing the JPEG compressed image. |
encodingTable | An array of bytes containing the encoding table. |
alpha | An array of bytes containing the zlib encoded alpha channel data for each pixel in the image. |
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.
The simplest way to use the FSDefineJPEGImage3 class is to use the constructor that specifies the JPEG file to initialise the object:
File aFile = new File(filename); byte[] bytes = new byte[(int) aFile.length()]; byte[] alpha = new byte[width * height]; byte[] compressedAlpha = null; try { FileInputStream imageContents = new FileInputStream(aFile); imageContents.read(bytes); imageContents.close(); // Set the level of transparency; for (int i = 0; i < bytes.length; i++) alpha[i] = (byte) 128; Deflater deflater = new Deflater(); byte[] tmp = new byte[alpha.length]; deflater.setInput(alpha); deflater.finish(); int bytesCompressed = deflater.deflate(tmp); compressedAlpha = new byte[bytesCompressed]; for (int i = 0; i < bytesCompressed; i++) compressedAlpha[i] = tmp[i]; } catch (FileNotFoundException e) { throw new FileNotFoundException(filename); } catch (IOException e) { throw new IOException(filename); } movie.add(new FSDefineJPEGImage3(movie.newIdentifier(), bytes, null, compressedAlpha));
This generates an object with an empty encoding table, however the image will still be displayed correctly. The empty encoding table is not a null object. The alpha channel data is set so the image is completely opaque.
The FSDefineJPEGImage3 class represents the DefineBitsJPEG3 tag from the Macromedia Flash (SWF) File Format Specification. It was introduced in Flash 3.
Field Summary |
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Fields inherited from class com.flagstone.transform.FSDefineObject |
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identifier |
Constructor Summary | |
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FSDefineJPEGImage3(FSCoder coder)
Construct an FSDefineJPEGImage3 object, initialising it with values decoded from an encoded object. |
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FSDefineJPEGImage3(FSDefineJPEGImage3 obj)
Constructs an FSDefineJPEGImage object by copying values from an existing object. |
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FSDefineJPEGImage3(int anIdentifier,
byte[] imageBytes,
byte[] encodingBytes,
byte[] alphaBytes)
Constructs an FSDefineJPEGImage3 object with the specified image data, encoding table and alpha channel data. |
Method Summary | |
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void |
appendDescription(java.lang.StringBuffer buffer,
int depth)
AppendDescription is used to present a string description of the object including all nested objects up to a specified depth. |
java.lang.Object |
clone()
Creates a deep copy of the entire object. |
void |
decode(FSCoder coder)
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void |
encode(FSCoder coder)
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boolean |
equals(java.lang.Object anObject)
Returns true if anObject is equal to this one. |
byte[] |
getCompressedAlpha()
Gets the alpha channel data. |
byte[] |
getEncodingTable()
Gets the encoding table. |
int |
getHeight()
Gets the height of the image in pixels. |
byte[] |
getImage()
Gets the image data. |
int |
getWidth()
Gets the width of the image in pixels. |
int |
length(FSCoder coder)
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void |
setCompressedAlpha(byte[] bytes)
Sets the alpha channel data with the zlib compressed data. |
void |
setEncodingTable(byte[] bytes)
Sets the encoding table. |
void |
setImage(byte[] bytes)
Sets the image data. |
Methods inherited from class com.flagstone.transform.FSDefineObject |
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getIdentifier, setIdentifier |
Methods inherited from class com.flagstone.transform.FSMovieObject |
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getType |
Methods inherited from class com.flagstone.transform.FSTransformObject |
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name, toString |
Methods inherited from class java.lang.Object |
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finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Constructor Detail |
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public FSDefineJPEGImage3(FSCoder coder)
coder
- an FSCoder containing the binary data.public FSDefineJPEGImage3(int anIdentifier, byte[] imageBytes, byte[] encodingBytes, byte[] alphaBytes)
anIdentifier
- the unique identifier for this objectimageBytes
- byte array containing the image dataencodingBytes
- byte array containing the encoding tablealphaBytes
- byte array containing the zlib compressed alpha channel datapublic FSDefineJPEGImage3(FSDefineJPEGImage3 obj)
obj
- an FSDefineJPEGImage object.Method Detail |
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public byte[] getEncodingTable()
public int getWidth()
public int getHeight()
public byte[] getImage()
public byte[] getCompressedAlpha()
public void setEncodingTable(byte[] bytes)
bytes
- byte array containing the encoding table.public void setImage(byte[] bytes)
bytes
- an array of bytes containing the image table.public void setCompressedAlpha(byte[] bytes)
bytes
- array of bytes containing zlib encoded alpha channel.public java.lang.Object clone()
FSTransformObject
clone
in class FSTransformObject
public boolean equals(java.lang.Object anObject)
FSMovieObject
equals
in class FSMovieObject
public void appendDescription(java.lang.StringBuffer buffer, int depth)
FSTransformObject
appendDescription
in class FSDefineObject
buffer
- a StringBuffer to which the description of each object is
appended.depth
- the maximum level of nesting up to which objects will be
displayed.public int length(FSCoder coder)
length
in class FSDefineObject
public void encode(FSCoder coder)
encode
in class FSDefineObject
public void decode(FSCoder coder)
decode
in class FSDefineObject
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