gifimagemetadata.java

java1.6众多例子参考

/*
 * @(#)GIFImageMetadata.java	1.31 05/11/17
 *
 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package com.sun.imageio.plugins.gif;

import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import javax.imageio.ImageTypeSpecifier;
import javax.imageio.metadata.IIOInvalidTreeException;
import javax.imageio.metadata.IIOMetadata;
import javax.imageio.metadata.IIOMetadataNode;
import javax.imageio.metadata.IIOMetadataFormat;
import javax.imageio.metadata.IIOMetadataFormatImpl;
import org.w3c.dom.Node;

/**
 * @version 0.5
 */
public class GIFImageMetadata extends GIFMetadata {

    // package scope
    static final String
        nativeMetadataFormatName = "javax_imageio_gif_image_1.0";

    static final String[] disposalMethodNames = {
        "none",
        "doNotDispose",
        "restoreToBackgroundColor",
        "restoreToPrevious",
        "undefinedDisposalMethod4",
        "undefinedDisposalMethod5",
        "undefinedDisposalMethod6",
        "undefinedDisposalMethod7"
    };

    // Fields from Image Descriptor
    public int imageLeftPosition;
    public int imageTopPosition;
    public int imageWidth;
    public int imageHeight;
    public boolean interlaceFlag = false;
    public boolean sortFlag = false;
    public byte[] localColorTable = null;

    // Fields from Graphic Control Extension
    public int disposalMethod = 0;
    public boolean userInputFlag = false;
    public boolean transparentColorFlag = false;
    public int delayTime = 0;
    public int transparentColorIndex = 0;

    // Fields from Plain Text Extension
    public boolean hasPlainTextExtension = false;
    public int textGridLeft;
    public int textGridTop;
    public int textGridWidth;
    public int textGridHeight;
    public int characterCellWidth;
    public int characterCellHeight;
    public int textForegroundColor;
    public int textBackgroundColor;
    public byte[] text;

    // Fields from ApplicationExtension
    // List of byte[]
    public List applicationIDs = null; // new ArrayList();

    // List of byte[]
    public List authenticationCodes = null; // new ArrayList();

    // List of byte[]
    public List applicationData = null; // new ArrayList();

    // Fields from CommentExtension
    // List of byte[]
    public List comments = null; // new ArrayList();

    protected GIFImageMetadata(boolean standardMetadataFormatSupported,
                               String nativeMetadataFormatName,
                               String nativeMetadataFormatClassName,
                               String[] extraMetadataFormatNames,
                               String[] extraMetadataFormatClassNames)
    {
        super(standardMetadataFormatSupported,
              nativeMetadataFormatName,
              nativeMetadataFormatClassName,
              extraMetadataFormatNames,
              extraMetadataFormatClassNames);
    }
    
    public GIFImageMetadata() {
        this(true,
              nativeMetadataFormatName,
              "com.sun.imageio.plugins.gif.GIFImageMetadataFormat",
              null, null);
    }
    
    public boolean isReadOnly() {
        return true;
    }

    public Node getAsTree(String formatName) {
        if (formatName.equals(nativeMetadataFormatName)) {
            return getNativeTree();
        } else if (formatName.equals
                   (IIOMetadataFormatImpl.standardMetadataFormatName)) {
            return getStandardTree();
        } else {
            throw new IllegalArgumentException("Not a recognized format!");
        }
    }

    private String toISO8859(byte[] data) {
        try {
            return new String(data, "ISO-8859-1");
        } catch (UnsupportedEncodingException e) {
            return "";
        }
    }

    private Node getNativeTree() {
        IIOMetadataNode node; // scratch node
        IIOMetadataNode root =
            new IIOMetadataNode(nativeMetadataFormatName);

        // Image descriptor
        node = new IIOMetadataNode("ImageDescriptor");
        node.setAttribute("imageLeftPosition",
                          Integer.toString(imageLeftPosition));
        node.setAttribute("imageTopPosition",
                          Integer.toString(imageTopPosition));
        node.setAttribute("imageWidth", Integer.toString(imageWidth));
        node.setAttribute("imageHeight", Integer.toString(imageHeight));
        node.setAttribute("interlaceFlag",
                          interlaceFlag ? "true" : "false");
        root.appendChild(node);

        // Local color table
        if (localColorTable != null) {
            node = new IIOMetadataNode("LocalColorTable");
            int numEntries = localColorTable.length/3;
            node.setAttribute("sizeOfLocalColorTable",
                              Integer.toString(numEntries));
            node.setAttribute("sortFlag",
                              sortFlag ? "TRUE" : "FALSE");
            
            for (int i = 0; i < numEntries; i++) {
                IIOMetadataNode entry =
                    new IIOMetadataNode("ColorTableEntry");
                entry.setAttribute("index", Integer.toString(i));
                int r = localColorTable[3*i] & 0xff;
                int g = localColorTable[3*i + 1] & 0xff;
                int b = localColorTable[3*i + 2] & 0xff;
                entry.setAttribute("red", Integer.toString(r));
                entry.setAttribute("green", Integer.toString(g));
                entry.setAttribute("blue", Integer.toString(b));
                node.appendChild(entry);
            }
            root.appendChild(node);
        }

        // Graphic control extension
        node = new IIOMetadataNode("GraphicControlExtension");
        node.setAttribute("disposalMethod",
                          disposalMethodNames[disposalMethod]);
        node.setAttribute("userInputFlag",
                          userInputFlag ? "true" : "false");
        node.setAttribute("transparentColorFlag",
                          transparentColorFlag ? "true" : "false");
        node.setAttribute("delayTime", 
                          Integer.toString(delayTime));
        node.setAttribute("transparentColorIndex",
                          Integer.toString(transparentColorIndex));
        root.appendChild(node);

        if (hasPlainTextExtension) {
            node = new IIOMetadataNode("PlainTextExtension");
            node.setAttribute("textGridLeft",
                              Integer.toString(textGridLeft));
            node.setAttribute("textGridTop",
                              Integer.toString(textGridTop));
            node.setAttribute("textGridWidth",
                              Integer.toString(textGridWidth));
            node.setAttribute("textGridHeight",
                              Integer.toString(textGridHeight));
            node.setAttribute("characterCellWidth",
                              Integer.toString(characterCellWidth));
            node.setAttribute("characterCellHeight",
                              Integer.toString(characterCellHeight));
            node.setAttribute("textForegroundColor",
                              Integer.toString(textForegroundColor));
            node.setAttribute("textBackgroundColor",
                              Integer.toString(textBackgroundColor));
            node.setAttribute("text", toISO8859(text));

            root.appendChild(node);
        }

        // Application extensions
        int numAppExtensions = applicationIDs == null ?
            0 : applicationIDs.size();
        if (numAppExtensions > 0) {
            node = new IIOMetadataNode("ApplicationExtensions");
            for (int i = 0; i < numAppExtensions; i++) {
                IIOMetadataNode appExtNode =
                    new IIOMetadataNode("ApplicationExtension");
                byte[] applicationID = (byte[])applicationIDs.get(i);
                appExtNode.setAttribute("applicationID",
                                        toISO8859(applicationID));
                byte[] authenticationCode = (byte[])authenticationCodes.get(i);