GIF速度の再生に関しては-私もこの問題に遭遇しました。私が正しく覚えている場合、これはGIFファイルのフレームレートの「デフォルト」(または提供されていない?)値が原因でした。一部のWebブラウザは、GIFが正しく再生されるように、そのフレームレートを「オーバーライド」しました。
その結果、GIFを変換し(GIFを読み取る-> GIFを書き込む)、ユーザーが提供するフレームレートを提供するクラスを作成しました。com.madgag.gif.fmsware.AnimatedGifEncoder
classは、Mavenを介してプロジェクトにリンクする外部ライブラリです。animated-gif-lib-1.0.jar
public final class GIFUtils {
private GIFUtils() {
}
public static List<BufferedImage> extractFrames(String filePath) throws IOException {
return extractFrames(new File(filePath));
}
public static List<BufferedImage> extractFrames(File file) throws IOException {
List<BufferedImage> imgs = new LinkedList<BufferedImage>();
ImageReader reader = ImageIO.getImageReadersBySuffix("GIF").next();
ImageInputStream in = null;
try {
in = ImageIO.createImageInputStream(new FileInputStream(file));
reader.setInput(in);
BufferedImage img = null;
int count = reader.getNumImages(true);
for(int i = 0; i < count; i++) {
Node tree = reader.getImageMetadata(i).getAsTree("javax_imageio_gif_image_1.0");
int x = Integer.valueOf(tree.getChildNodes().item(0).getAttributes()
.getNamedItem("imageLeftPosition").getNodeValue());
int y = Integer.valueOf(tree.getChildNodes().item(0).getAttributes()
.getNamedItem("imageTopPosition").getNodeValue());
BufferedImage image = reader.read(i);
if(img == null) {
img = new BufferedImage(image.getWidth() + x, image.getHeight() + y,
BufferedImage.TYPE_4BYTE_ABGR);
}
Graphics2D g = img.createGraphics();
ImageUtils.setBestRenderHints(g);
g.drawImage(image, x, y, null);
imgs.add(ImageUtils.copy(img));
}
}
finally {
if(in != null) {
in.close();
}
}
return imgs;
}
public static void writeGif(List<BufferedImage> images, File gifFile, int millisForFrame)
throws FileNotFoundException, IOException {
BufferedImage firstImage = images.get(0);
int type = firstImage.getType();
ImageOutputStream output = new FileImageOutputStream(gifFile);
// create a gif sequence with the type of the first image, 1 second
// between frames, which loops continuously
GifSequenceWriter writer = new GifSequenceWriter(output, type, 100, false);
// write out the first image to our sequence...
writer.writeToSequence(firstImage);
for(int i = 1; i < images.size(); i++) {
BufferedImage nextImage = images.get(i);
writer.writeToSequence(nextImage);
}
writer.close();
output.close();
}
public static Image createGif(List<BufferedImage> images, int millisForFrame) {
AnimatedGifEncoder g = new AnimatedGifEncoder();
ByteArrayOutputStream out = new ByteArrayOutputStream(5 * 1024 * 1024);
g.start(out);
g.setDelay(millisForFrame);
g.setRepeat(1);
for(BufferedImage i : images) {
g.addFrame(i);
}
g.finish();
byte[] bytes = out.toByteArray();
return Toolkit.getDefaultToolkit().createImage(bytes);
}
そしてGifSequenceWriter
このように見えます:
public class GifSequenceWriter {
protected ImageWriter gifWriter;
protected ImageWriteParam imageWriteParam;
protected IIOMetadata imageMetaData;
public GifSequenceWriter(ImageOutputStream outputStream, int imageType, int timeBetweenFramesMS,
boolean loopContinuously) throws IIOException, IOException {
gifWriter = getWriter();
imageWriteParam = gifWriter.getDefaultWriteParam();
ImageTypeSpecifier 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);
}
public void close() throws IOException {
gifWriter.endWriteSequence();
}
private static ImageWriter getWriter() throws IIOException {
Iterator<ImageWriter> iter = ImageIO.getImageWritersBySuffix("gif");
if(!iter.hasNext()) {
throw new IIOException("No GIF Image Writers Exist");
}
return iter.next();
}
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;
}
}