Example usage for javax.imageio.stream ImageInputStream seek

Introduction

In this page you can find the example usage for javax.imageio.stream ImageInputStream seek.

Prototype

void seek(long pos) throws IOException;

Source Link

Document

Sets the current stream position to the desired location.

Usage

From source file:org.apache.xmlgraphics.image.loader.impl.ImageLoaderRawCCITTFax.java

/** {@inheritDoc} */
public Image loadImage(ImageInfo info, Map hints, ImageSessionContext session)
        throws ImageException, IOException {
    if (!MimeConstants.MIME_TIFF.equals(info.getMimeType())) {
        throw new IllegalArgumentException(
                "ImageInfo must be from a image with MIME type: " + MimeConstants.MIME_TIFF);
    }//  www  . jav  a  2 s.  com
    int fillOrder = 1;
    int compression = TIFFImage.COMP_NONE;
    long stripOffset;
    long stripLength;
    TIFFDirectory dir;

    Source src = session.needSource(info.getOriginalURI());
    ImageInputStream in = ImageUtil.needImageInputStream(src);
    in.mark();
    try {
        SeekableStream seekable = new SeekableStreamAdapter(in);
        dir = new TIFFDirectory(seekable, 0);
        TIFFField fld;

        fld = dir.getField(TIFFImageDecoder.TIFF_COMPRESSION);
        if (fld != null) {
            compression = fld.getAsInt(0);
            switch (compression) {
            case TIFFImage.COMP_FAX_G3_1D:
            case TIFFImage.COMP_FAX_G3_2D:
            case TIFFImage.COMP_FAX_G4_2D:
                break;
            default:
                log.debug("Unsupported compression " + compression);
                throw new ImageException("ImageLoader doesn't support TIFF compression: " + compression);
            }
        }
        //Read information used for raw embedding
        fld = dir.getField(TIFFImageDecoder.TIFF_FILL_ORDER);
        if (fld != null) {
            fillOrder = fld.getAsInt(0);
        }

        int stripCount;
        fld = dir.getField(TIFFImageDecoder.TIFF_ROWS_PER_STRIP);
        if (fld == null) {
            stripCount = 1;
        } else {
            stripCount = (int) (info.getSize().getHeightPx() / fld.getAsLong(0));
        }
        if (stripCount > 1) {
            log.debug("More than one strip found in TIFF image.");
            throw new ImageException("ImageLoader doesn't support multiple strips");
        }
        stripOffset = dir.getField(TIFFImageDecoder.TIFF_STRIP_OFFSETS).getAsLong(0);
        stripLength = dir.getField(TIFFImageDecoder.TIFF_STRIP_BYTE_COUNTS).getAsLong(0);
    } finally {
        in.reset();
    }

    in.seek(stripOffset);
    InputStream subin = new SubInputStream(ImageUtil.needInputStream(src), stripLength, true);
    if (fillOrder == 2) {
        //Decorate to flip bit order
        subin = new FillOrderChangeInputStream(subin);
    }
    ImageRawCCITTFax rawImage = new ImageRawCCITTFax(info, subin, compression);
    //Strip stream from source as we pass it on internally
    ImageUtil.removeStreams(src);
    return rawImage;
}

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