com.enterprisemath.utils.image.GifAnimatorWriter Maven / Gradle / Ivy

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Collection of utility classes for large scale projects focusing on robust and testable code.
There is a newer version: 4.1.1
package com.enterprisemath.utils.image;

import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;

import javax.imageio.IIOImage;
import javax.imageio.ImageIO;
import javax.imageio.ImageTypeSpecifier;
import javax.imageio.ImageWriteParam;
import javax.imageio.ImageWriter;
import javax.imageio.metadata.IIOInvalidTreeException;
import javax.imageio.metadata.IIOMetadata;
import javax.imageio.metadata.IIOMetadataNode;
import javax.imageio.stream.ImageOutputStream;
import javax.imageio.stream.MemoryCacheImageOutputStream;

import org.apache.commons.io.IOUtils;
import org.apache.commons.lang3.builder.ToStringBuilder;

/**
 * Class which writes animation into a gif image file format.
 * This library is derived from Animated GIF Writer original is at
 * http://elliot.kroo.net/software/java/GifSequenceWriter/. 
 * License is Creative Commons Attribution 3.0 Unported License
 * which allows you to do whatever you like as far as you remain the credit.
 * 
 * @author radek.hecl
 *
 */
public class GifAnimatorWriter {

    /**
     * Builder object.
     */
    public static class Builder {

        /**
         * Builds the result object.
         * 
         * @return created object
         */
        public GifAnimatorWriter build() {
            return new GifAnimatorWriter(this);
        }

    }

    /**
     * Creates new instance.
     * 
     * @param builder builder object
     */
    public GifAnimatorWriter(Builder builder) {
        guardInvariants();
    }

    /**
     * Guards this object to be consistent. Throws exception if this is not the case.
     */
    private void guardInvariants() {
    }

    /**
     * Writes animation as a gif file format and returns the data blob.
     * 
     * @param animation animation which is captured
     * @return data blob containing the gif encoded animation  
     */
    public byte[] writeAnimation(ImageAnimation animation) {

        ImageWriter writer = ImageIO.getImageWritersBySuffix("gif").next();
        ImageWriteParam param = writer.getDefaultWriteParam();
        ImageTypeSpecifier imageTypeSpecifier = ImageTypeSpecifier.createFromBufferedImageType(BufferedImage.TYPE_4BYTE_ABGR);
        IIOMetadata metaData = writer.getDefaultImageMetadata(imageTypeSpecifier, param);
        String metaFormatName = metaData.getNativeMetadataFormatName();

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

        IIOMetadataNode graphicsControlExtensionNode = getNode(root, "GraphicControlExtension");
        graphicsControlExtensionNode.setAttribute("disposalMethod", "none");
        graphicsControlExtensionNode.setAttribute("userInputFlag", "FALSE");
        graphicsControlExtensionNode.setAttribute("transparentColorFlag", "FALSE");
        graphicsControlExtensionNode.setAttribute("delayTime", Integer.toString(animation.getFrameDuration() / 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 = 0;

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

        ByteArrayOutputStream os = null;
        ImageOutputStream ios = null;
        try {
            os = new ByteArrayOutputStream();
            ios = new MemoryCacheImageOutputStream(os);
            metaData.setFromTree(metaFormatName, root);

            writer.setOutput(ios);
            
            writer.prepareWriteSequence(null);

            for (int i = 0; i < animation.getNumFrames(); ++i) {
                writer.writeToSequence(new IIOImage(animation.getFrame(i), null, metaData), param);
            }
            writer.endWriteSequence();
            
            ios.close();
            os.close();
            ios = null;
        } catch (IIOInvalidTreeException e) {
            throw new RuntimeException(e);
        } catch (IOException e) {
            throw new RuntimeException(e);
        } finally {
            if (ios != null) {
                try {
                    ios.close();
                } catch (Exception e) {
                    // just suppress as this is suppose to be quiet
                }
            }
            IOUtils.closeQuietly(os);
        }

        return os.toByteArray();
    }

    /**
     * Returns an existing child node, or creates and returns a new child node (if 
     * the requested node does not exist).
     * 
     * @param rootNode root node where the search begins
     * @param nodeName the name of the child node
     * 
     * @return founded child node or new node if specified node doesn't exists
     */
    private 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);
    }

    @Override
    public String toString() {
        return ToStringBuilder.reflectionToString(this);
    }

    /**
     * Creates new instance.
     * 
     * @return created instance
     */
    public static GifAnimatorWriter create() {
        return new GifAnimatorWriter.Builder().
                build();
    }

}