GifSequenceWriter.java

/*
  GifSequenceWriter.java

  (c) 2016 Edward Swartz

  All rights reserved. This program and the accompanying materials
  are made available under the terms of the Eclipse Public License v1.0
  which accompanies this distribution, and is available at
  http://www.eclipse.org/legal/epl-v10.html
 */
package v9t9.video.imageimport;
// 
//  GifSequenceWriter.java
//  
//  Created by Elliot Kroo on 2009-04-25.
//
// This work is licensed under the Creative Commons Attribution 3.0 Unported
// License. To view a copy of this license, visit
// http://creativecommons.org/licenses/by/3.0/ or send a letter to Creative
// Commons, 171 Second Street, Suite 300, San Francisco, California, 94105, USA.


import javax.imageio.*;
import javax.imageio.metadata.*;
import javax.imageio.stream.*;

import java.awt.image.*;
import java.io.*;
import java.util.Iterator;

public class GifSequenceWriter {
  protected ImageWriter gifWriter;
  protected ImageWriteParam imageWriteParam;
  protected IIOMetadata imageMetaData;
private ImageTypeSpecifier imageTypeSpecifier;
  
  /**
   * Creates a new GifSequenceWriter
   * 
   * @param outputStream the ImageOutputStream to be written to
   * @param imageType one of the imageTypes specified in BufferedImage
   * @param timeBetweenFramesMS the time between frames in miliseconds
   * @param loopContinuously wether the gif should loop repeatedly
   * @throws IIOException if no gif ImageWriters are found
   *
   * @author Elliot Kroo (elliot[at]kroo[dot]net)
   */
  public GifSequenceWriter(
      ImageOutputStream outputStream,
      int imageType,
      int timeBetweenFramesMS,
      boolean loopContinuously) throws IIOException, IOException {
		// my method to create a writer
		gifWriter = getWriter();
		imageWriteParam = gifWriter.getDefaultWriteParam();
		imageTypeSpecifier = ImageTypeSpecifier
				.createFromBufferedImageType(imageType);

		imageMetaData = gifWriter.getDefaultImageMetadata(imageTypeSpecifier,
				imageWriteParam);

		String metaFormatName = imageMetaData.getNativeMetadataFormatName();

		IIOMetadataNode root = (IIOMetadataNode) imageMetaData
				.getAsTree(metaFormatName);

		IIOMetadataNode graphicsControlExtensionNode = getNode(root,
				"GraphicControlExtension");

		graphicsControlExtensionNode.setAttribute("disposalMethod", "none");
		graphicsControlExtensionNode.setAttribute("userInputFlag", "FALSE");
		graphicsControlExtensionNode.setAttribute("transparentColorFlag",
				"FALSE");
		graphicsControlExtensionNode.setAttribute("delayTime",
				Integer.toString(timeBetweenFramesMS / 10));
		graphicsControlExtensionNode.setAttribute("transparentColorIndex", "0");

		IIOMetadataNode commentsNode = getNode(root, "CommentExtensions");
		commentsNode.setAttribute("CommentExtension", "Created by MAH");

		IIOMetadataNode appEntensionsNode = getNode(root,
				"ApplicationExtensions");

		IIOMetadataNode child = new IIOMetadataNode("ApplicationExtension");

		child.setAttribute("applicationID", "NETSCAPE");
		child.setAttribute("authenticationCode", "2.0");

		int loop = loopContinuously ? 0 : 1;

		child.setUserObject(new byte[] { 0x1, (byte) (loop & 0xFF),
				(byte) ((loop >> 8) & 0xFF) });
		appEntensionsNode.appendChild(child);

		imageMetaData.setFromTree(metaFormatName, root);

		gifWriter.setOutput(outputStream);

		gifWriter.prepareWriteSequence(null);
  }
  
  public void writeToSequence(RenderedImage img) throws IOException {
		gifWriter.writeToSequence(new IIOImage(img, null, imageMetaData),
				imageWriteParam);
	}

	/**
	 * Close this GifSequenceWriter object. This does not close the underlying
	 * stream, just finishes off the GIF.
	 */
	public void close() throws IOException {
		gifWriter.endWriteSequence();
	}

	/**
	 * Returns the first available GIF ImageWriter using
	 * ImageIO.getImageWritersBySuffix("gif").
	 * 
	 * @return a GIF ImageWriter object
	 * @throws IIOException
	 *             if no GIF image writers are returned
	 */
	private static ImageWriter getWriter() throws IIOException {
		Iterator<ImageWriter> iter = ImageIO.getImageWritersBySuffix("gif");
		if (!iter.hasNext()) {
			throw new IIOException("No GIF Image Writers Exist");
		} else {
			return iter.next();
		}
	}

	/**
	 * Returns an existing child node, or creates and returns a new child node
	 * (if the requested node does not exist).
	 * 
	 * @param rootNode
	 *            the <tt>IIOMetadataNode</tt> to search for the child node.
	 * @param nodeName
	 *            the name of the child node.
	 * 
	 * @return the child node, if found or a new node created with the given
	 *         name.
	 */
	private static IIOMetadataNode getNode(IIOMetadataNode rootNode,
			String nodeName) {
		int nNodes = rootNode.getLength();
		for (int i = 0; i < nNodes; i++) {
			if (rootNode.item(i).getNodeName().compareToIgnoreCase(nodeName) == 0) {
				return ((IIOMetadataNode) rootNode.item(i));
			}
		}
		IIOMetadataNode node = new IIOMetadataNode(nodeName);
		rootNode.appendChild(node);
		return (node);
	}

	/**
	 * public GifSequenceWriter( BufferedOutputStream outputStream, int
	 * imageType, int timeBetweenFramesMS, boolean loopContinuously) {
	 */

	public static void main(String[] args) throws Exception {
		if (args.length > 1) {
			// grab the output image type from the first image in the sequence
			BufferedImage firstImage = ImageIO.read(new File(args[0]));

			// create a new BufferedOutputStream with the last argument
			ImageOutputStream output = new FileImageOutputStream(new File(
					args[args.length - 1]));

			// create a gif sequence with the type of the first image, 1 second
			// between frames, which loops continuously
			GifSequenceWriter writer = new GifSequenceWriter(output,
					firstImage.getType(), 1, false);

			// write out the first image to our sequence...
			writer.writeToSequence(firstImage);
			for (int i = 1; i < args.length - 1; i++) {
				BufferedImage nextImage = ImageIO.read(new File(args[i]));
				writer.writeToSequence(nextImage);
			}

			writer.close();
			output.close();
		} else {
			System.out
					.println("Usage: java GifSequenceWriter [list of gif files] [output file]");
		}
  }
}