153 lines
5.6 KiB
HTML
153 lines
5.6 KiB
HTML
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<!--NewPage-->
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<html>
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<head>
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<!-- Generated by javadoc on Sat May 10 12:23:02 1997 -->
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<a name="_top_"></a>
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<title>
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Class GIFEncoder
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</title>
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</head>
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<body>
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<h1>
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Class GIFEncoder
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</h1>
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<pre>
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<a href="java.lang.Object.html#_top_">java.lang.Object</a>
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+----GIFEncoder
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</pre>
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<hr>
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<dl>
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<dt> public class <b>GIFEncoder</b>
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<dt> extends <a href="java.lang.Object.html#_top_">Object</a>
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</dl>
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GIFEncoder is a class which takes an image and saves it to a stream
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using the GIF file format (<A
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HREF="http://www.dcs.ed.ac.uk/%7Emxr/gfx/">Graphics Interchange
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Format</A>). A GIFEncoder
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is constructed with either an AWT Image (which must be fully
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loaded) or a set of RGB arrays. The image can be written out with a
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call to <CODE>Write</CODE>.<P>
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Three caveats:
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<UL>
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<LI>GIFEncoder will convert the image to indexed color upon
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construction. This will take some time, depending on the size of
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the image. Also, actually writing the image out (Write) will take
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time.<P>
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<LI>The image cannot have more than 256 colors, since GIF is an 8
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bit format. For a 24 bit to 8 bit quantization algorithm, see
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Graphics Gems II III.2 by Xialoin Wu. Or check out his <A
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HREF="http://www.csd.uwo.ca/faculty/wu/cq.c">C source</A>.<P>
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<LI>Since the image must be completely loaded into memory,
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GIFEncoder may have problems with large images. Attempting to
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encode an image which will not fit into memory will probably
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result in the following exception:<P>
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<CODE>java.awt.AWTException: Grabber returned false: 192</CODE><P>
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</UL><P>
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GIFEncoder is based upon gifsave.c, which was written and released
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by:<P>
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<CENTER>
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Sverre H. Huseby<BR>
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Bjoelsengt. 17<BR>
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N-0468 Oslo<BR>
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Norway<P>
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Phone: +47 2 230539<BR>
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sverrehu@ifi.uio.no<P>
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</CENTER>
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<dl>
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<dt> <b>Version:</b>
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<dd> 0.90 21 Apr 1996
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<dt> <b>Author:</b>
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<dd> <A HREF="http://www.cs.brown.edu/people/amd/">Adam Doppelt</A>
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</dl>
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<hr>
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<a name="index"></a>
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<h2>
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<img src="images/constructor-index.gif" width=275 height=38 alt="Constructor Index">
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</h2>
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<dl>
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<dt> <img src="images/yellow-ball-small.gif" width=6 height=6 alt=" o ">
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<a href="#GIFEncoder(byte[][], byte[][], byte[][])"><b>GIFEncoder</b></a>(byte[][], byte[][], byte[][])
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<dd> Construct a GIFEncoder.
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<dt> <img src="images/yellow-ball-small.gif" width=6 height=6 alt=" o ">
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<a href="#GIFEncoder(java.awt.Image)"><b>GIFEncoder</b></a>(Image)
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<dd> Construct a GIFEncoder.
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</dl>
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<h2>
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<img src="images/method-index.gif" width=207 height=38 alt="Method Index">
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</h2>
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<dl>
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<dt> <img src="images/red-ball-small.gif" width=6 height=6 alt=" o ">
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<a href="#Write(java.io.OutputStream)"><b>Write</b></a>(OutputStream)
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<dd> Writes the image out to a stream in the GIF file format.
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</dl>
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<a name="constructors"></a>
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<h2>
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<img src="images/constructors.gif" width=231 height=38 alt="Constructors">
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</h2>
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<a name="GIFEncoder"></a>
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<a name="GIFEncoder(java.awt.Image)"><img src="images/yellow-ball.gif" width=12 height=12 alt=" o "></a>
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<b>GIFEncoder</b>
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<pre>
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public GIFEncoder(<a href="java.awt.Image.html#_top_">Image</a> image) throws <a href="java.awt.AWTException.html#_top_">AWTException</a>
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</pre>
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<dl>
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<dd> Construct a GIFEncoder. The constructor will convert the image to
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an indexed color array. <B>This may take some time.</B><P>
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<dl>
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<dt> <b>Parameters:</b>
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<dd> image - The image to encode. The image <B>must</B> be
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completely loaded.
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<dt> <b>Throws:</b> <a href="java.awt.AWTException.html#_top_">AWTException</a>
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<dd> Will be thrown if the pixel grab fails. This
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can happen if Java runs out of memory. It may also indicate that the image
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contains more than 256 colors.
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</dl>
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</dl>
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<a name="GIFEncoder(byte[][], byte[][], byte[][])"><img src="images/yellow-ball.gif" width=12 height=12 alt=" o "></a>
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<b>GIFEncoder</b>
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<pre>
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public GIFEncoder(byte r[][],
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byte g[][],
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byte b[][]) throws <a href="java.awt.AWTException.html#_top_">AWTException</a>
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</pre>
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<dl>
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<dd> Construct a GIFEncoder. The constructor will convert the image to
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an indexed color array. <B>This may take some time.</B><P>
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Each array stores intensity values for the image. In other words,
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r[x][y] refers to the red intensity of the pixel at column x, row
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y.<P>
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<dl>
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<dt> <b>Parameters:</b>
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<dd> r - An array containing the red intensity values.
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<dd> g - An array containing the green intensity values.
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<dd> b - An array containing the blue intensity values.
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<dt> <b>Throws:</b> <a href="java.awt.AWTException.html#_top_">AWTException</a>
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<dd> Will be thrown if the image contains more than
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256 colors.
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</dl>
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</dl>
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<a name="methods"></a>
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<h2>
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<img src="images/methods.gif" width=151 height=38 alt="Methods">
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</h2>
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<a name="Write(java.io.OutputStream)"><img src="images/red-ball.gif" width=12 height=12 alt=" o "></a>
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<a name="Write"><b>Write</b></a>
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<pre>
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public void Write(<a href="java.io.OutputStream.html#_top_">OutputStream</a> output) throws <a href="java.io.IOException.html#_top_">IOException</a>
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</pre>
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<dl>
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<dd> Writes the image out to a stream in the GIF file format. This will
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be a single GIF87a image, non-interlaced, with no background color.
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<B>This may take some time.</B><P>
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<dl>
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<dt> <b>Parameters:</b>
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<dd> output - The stream to output to. This should probably be a
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buffered stream.
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<dt> <b>Throws:</b> <a href="java.io.IOException.html#_top_">IOException</a>
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<dd> Will be thrown if a write operation fails.
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</dl>
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</dl>
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</body>
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</html>
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