124 lines
4.3 KiB
Java
124 lines
4.3 KiB
Java
// This code was adapted from http://elliot.kroo.net/software/java/GifSequenceWriter/
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// It was available under CC By 3.0
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package lc.misc;
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import javax.imageio.*;
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import javax.imageio.metadata.*;
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import javax.imageio.stream.*;
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import java.awt.image.*;
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import java.io.*;
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import java.util.Iterator;
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public class GifSequenceWriter {
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protected ImageWriter gifWriter;
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protected ImageWriteParam imageWriteParam;
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protected IIOMetadata imageMetaData;
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/**
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* Creates a new GifSequenceWriter
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*
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* @param outputStream the ImageOutputStream to be written to
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* @param imageType one of the imageTypes specified in BufferedImage
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* @param timeBetweenFramesMS the time between frames in miliseconds
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* @param loopContinuously wether the gif should loop repeatedly
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* @throws IIOException if no gif ImageWriters are found
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* @author Elliot Kroo (elliot[at]kroo[dot]net)
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*/
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public GifSequenceWriter(
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ImageOutputStream outputStream,
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int imageType,
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int timeBetweenFramesMS,
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boolean loopContinuously)
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throws IIOException, IOException {
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// my method to create a writer
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gifWriter = getWriter();
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imageWriteParam = gifWriter.getDefaultWriteParam();
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ImageTypeSpecifier imageTypeSpecifier =
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ImageTypeSpecifier.createFromBufferedImageType(imageType);
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imageMetaData = gifWriter.getDefaultImageMetadata(imageTypeSpecifier, imageWriteParam);
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String metaFormatName = imageMetaData.getNativeMetadataFormatName();
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IIOMetadataNode root = (IIOMetadataNode) imageMetaData.getAsTree(metaFormatName);
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IIOMetadataNode graphicsControlExtensionNode = getNode(root, "GraphicControlExtension");
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graphicsControlExtensionNode.setAttribute("disposalMethod", "none");
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graphicsControlExtensionNode.setAttribute("userInputFlag", "FALSE");
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graphicsControlExtensionNode.setAttribute("transparentColorFlag", "FALSE");
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graphicsControlExtensionNode.setAttribute(
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"delayTime", Integer.toString(timeBetweenFramesMS / 10));
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graphicsControlExtensionNode.setAttribute("transparentColorIndex", "0");
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IIOMetadataNode commentsNode = getNode(root, "CommentExtensions");
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commentsNode.setAttribute("CommentExtension", "Created by MAH");
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IIOMetadataNode appEntensionsNode = getNode(root, "ApplicationExtensions");
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IIOMetadataNode child = new IIOMetadataNode("ApplicationExtension");
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child.setAttribute("applicationID", "NETSCAPE");
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child.setAttribute("authenticationCode", "2.0");
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int loop = loopContinuously ? 0 : 1;
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child.setUserObject(new byte[] {0x1, (byte) (loop & 0xFF), (byte) ((loop >> 8) & 0xFF)});
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appEntensionsNode.appendChild(child);
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imageMetaData.setFromTree(metaFormatName, root);
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gifWriter.setOutput(outputStream);
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gifWriter.prepareWriteSequence(null);
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}
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public void writeToSequence(RenderedImage img) throws IOException {
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gifWriter.writeToSequence(new IIOImage(img, null, imageMetaData), imageWriteParam);
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}
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/**
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* Close this GifSequenceWriter object. This does not close the underlying stream, just finishes
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* off the GIF.
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*/
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public void close() throws IOException {
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gifWriter.endWriteSequence();
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}
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/**
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* Returns the first available GIF ImageWriter using ImageIO.getImageWritersBySuffix("gif").
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*
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* @return a GIF ImageWriter object
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* @throws IIOException if no GIF image writers are returned
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*/
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private static ImageWriter getWriter() throws IIOException {
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Iterator<ImageWriter> iter = ImageIO.getImageWritersBySuffix("gif");
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if (!iter.hasNext()) {
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throw new IIOException("No GIF Image Writers Exist");
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} else {
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return iter.next();
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}
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}
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/**
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* Returns an existing child node, or creates and returns a new child node (if the requested node
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* does not exist).
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*
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* @param rootNode the <tt>IIOMetadataNode</tt> to search for the child node.
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* @param nodeName the name of the child node.
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* @return the child node, if found or a new node created with the given name.
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*/
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private static IIOMetadataNode getNode(IIOMetadataNode rootNode, String nodeName) {
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int nNodes = rootNode.getLength();
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for (int i = 0; i < nNodes; i++) {
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if (rootNode.item(i).getNodeName().compareToIgnoreCase(nodeName) == 0) {
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return ((IIOMetadataNode) rootNode.item(i));
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}
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}
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IIOMetadataNode node = new IIOMetadataNode(nodeName);
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rootNode.appendChild(node);
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return (node);
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}
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}
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