Java ImageIO.getImageReader方法代码示例

import javax.imageio.ImageIO; //导入方法依赖的package包/类
protected void doTest() throws IOException {
    BufferedImage biSrc = getSrc();

    ImageWriter writer = ImageIO.getImageWritersByFormatName("GIF").next();
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    ImageOutputStream ios = ImageIO.createImageOutputStream(baos);
    writer.setOutput(ios);

    ImageWriteParam writeParam = writer.getDefaultWriteParam();
    IIOMetadata imageMetadata =
        writer.getDefaultImageMetadata(new ImageTypeSpecifier(biSrc), writeParam);

    IIOMetadata streamMetadata = writer.getDefaultStreamMetadata(writeParam);

    IIOImage iioImg = new IIOImage(biSrc, null, imageMetadata);
    writer.write(streamMetadata, iioImg, writeParam);
    ios.close();

    ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
    ImageInputStream iis = ImageIO.createImageInputStream(bais);
    ImageReader reader = ImageIO.getImageReader(writer);
    reader.setInput(iis);
    BufferedImage dst = reader.read(0);

    // do test
    int x = dx / 2;
    int y = height / 2;

    for (int i = 0; i < usedColors.length; i++) {
        int dstRgb = dst.getRGB(x, y);
        System.out.println("dstColor: " + Integer.toHexString(dstRgb));
        int srcRgb = usedColors[i].getRGB();
        System.out.println("srcColor: " + Integer.toHexString(srcRgb));
        if (dstRgb != srcRgb) {
            throw new RuntimeException("wrong color " + i + ": " + Integer.toHexString(dstRgb));
        }
        x += dx;
    }

}
 

import javax.imageio.ImageIO; //导入方法依赖的package包/类
public static void test(String mimeType, boolean useStreamMeta,
                        String metaXml, String... boolXpaths)
    throws Exception
{
    BufferedImage img =
        new BufferedImage(16, 16, BufferedImage.TYPE_INT_RGB);
    ImageWriter iw = ImageIO.getImageWritersByMIMEType(mimeType).next();
    ByteArrayOutputStream os = new ByteArrayOutputStream();
    ImageOutputStream ios = new MemoryCacheImageOutputStream(os);
    iw.setOutput(ios);
    ImageWriteParam param = null;
    IIOMetadata streamMeta = iw.getDefaultStreamMetadata(param);
    IIOMetadata imageMeta =
        iw.getDefaultImageMetadata(new ImageTypeSpecifier(img), param);
    IIOMetadata meta = useStreamMeta ? streamMeta : imageMeta;
    Source src = new StreamSource(new StringReader(metaXml));
    DOMResult dst = new DOMResult();
    transform(src, dst);
    Document doc = (Document)dst.getNode();
    Element node = doc.getDocumentElement();
    String metaFormat = node.getNodeName();

    // Verify that the default metadata gets formatted correctly.
    verify(meta.getAsTree(metaFormat), boolXpaths, false);

    meta.mergeTree(metaFormat, node);

    // Verify that the merged metadata gets formatte correctly.
    verify(meta.getAsTree(metaFormat), boolXpaths, true);

    iw.write(streamMeta, new IIOImage(img, null, imageMeta), param);
    iw.dispose();
    ios.close();
    ImageReader ir = ImageIO.getImageReader(iw);
    byte[] bytes = os.toByteArray();
    if (bytes.length == 0)
        throw new AssertionError("Zero length image file");
    ByteArrayInputStream is = new ByteArrayInputStream(bytes);
    ImageInputStream iis = new MemoryCacheImageInputStream(is);
    ir.setInput(iis);
    if (useStreamMeta) meta = ir.getStreamMetadata();
    else meta = ir.getImageMetadata(0);

    // Verify again after writing and re-reading the image
    verify(meta.getAsTree(metaFormat), boolXpaths, true);
}
 

import javax.imageio.ImageIO; //导入方法依赖的package包/类
public static void main(String[] args) throws IOException {
    String format = "GIF";
    ImageWriter writer =
            ImageIO.getImageWritersByFormatName(format).next();
    if (writer == null) {
        throw new RuntimeException("No available writers for " + format);
    }

    BufferedImage img = createTestImage(100, 100, BufferedImage.TYPE_BYTE_GRAY);

    ImageWriteParam p = writer.getDefaultWriteParam();
    ImageTypeSpecifier type =
        ImageTypeSpecifier.createFromRenderedImage(img);
    IIOMetadata inImageMetadata =
        writer.getDefaultImageMetadata(type, p);

    IIOMetadata inStreamMetadata = writer.getDefaultStreamMetadata(p);

    // write and read image
    ByteArrayOutputStream baos = new ByteArrayOutputStream();

    ImageOutputStream ios = ImageIO.createImageOutputStream(baos);
    writer.setOutput(ios);

    writer.write(inStreamMetadata, new IIOImage(img, null, inImageMetadata), p);

    ios.flush();
    ios.close();

    // read result
    ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
    ImageInputStream iis = ImageIO.createImageInputStream(bais);
    ImageReader reader = ImageIO.getImageReader(writer);
    reader.setInput(iis);

    IIOMetadata outStreamMetadata = reader.getStreamMetadata();

    GIFStreamMetadata gifStreamMetadata = (GIFStreamMetadata)outStreamMetadata;

    if (gifStreamMetadata.logicalScreenWidth != img.getWidth() ||
            gifStreamMetadata.logicalScreenHeight != img.getHeight()) {
        throw new RuntimeException("Test failed due to wrong logical screen dimension.");
    }
}
 

import javax.imageio.ImageIO; //导入方法依赖的package包/类
public void doTest() {
    try {
        System.out.println(this.getDescription());
        if (param.getCompressionMode() != ImageWriteParam.MODE_EXPLICIT) {
            System.out.println("Warning: compression mode is not MODE_EXPLICIT");
        }
        // change metadata according to ImageWriteParam
        IIOMetadata new_meta = iw.convertImageMetadata(meta, new ImageTypeSpecifier(img), param);

        IIOImage iio_img = new IIOImage(img, null, new_meta);

        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        ImageOutputStream ios = ImageIO.createImageOutputStream(baos);
        iw.setOutput(ios);
        System.out.print("write image...");
        System.out.println("Current compression Type is \""+param.getCompressionType()+"\"");
        iw.write(new_meta, iio_img, param);
        //iw.write(iio_img);
        System.out.println("OK");
        System.out.print("read image ... ");
        ios.flush();

        byte[] ba_image = baos.toByteArray();

        System.out.println("Array length=" + ba_image.length);
        FileOutputStream fos = new FileOutputStream(new File(param.getCompressionType()+".bmp"));
        fos.write(ba_image);
        fos.flush();
        fos = null;
        ByteArrayInputStream bais = new ByteArrayInputStream(ba_image);

        ImageReader ir = ImageIO.getImageReader(iw);
        ir.setInput(ImageIO.createImageInputStream(bais));

        BufferedImage res = ir.read(0);
        System.out.println("OK");

        if (!param.getCompressionType().equals("BI_JPEG")) {
            System.out.print("compare images ... ");
            boolean r = compare(img,res);
            System.out.println(r?"OK":"FAILED");
            if (!r) {
                throw new RuntimeException("Compared images are not equals. Test failed.");
            }
        }


        BMPMetadata mdata = (BMPMetadata)ir.getImageMetadata(0);

        if (!param.getCompressionType().equals(param.getCompressionTypes()[mdata.compression])) {
            throw new RuntimeException("Different compression value");
        }

    } catch (Exception ex) {
        ex.printStackTrace();
        throw new RuntimeException("Unexpected exception: " + ex);
    }

}