Example usage for javax.imageio.stream ImageInputStream skipBytes

List of usage examples for javax.imageio.stream ImageInputStream skipBytes

Introduction

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

Prototype

long skipBytes(long n) throws IOException;

Source Link

Document

Moves the stream position forward by a given number of bytes.

Usage

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

/** {@inheritDoc} */
public Image loadImage(ImageInfo info, Map hints, ImageSessionContext session)
        throws ImageException, IOException {
    if (!MimeConstants.MIME_JPEG.equals(info.getMimeType())) {
        throw new IllegalArgumentException(
                "ImageInfo must be from a image with MIME type: " + MimeConstants.MIME_JPEG);
    }/*from  w  ww . j av a2  s  .com*/

    ColorSpace colorSpace = null;
    boolean appeFound = false;
    int sofType = 0;
    ByteArrayOutputStream iccStream = null;

    Source src = session.needSource(info.getOriginalURI());
    ImageInputStream in = ImageUtil.needImageInputStream(src);
    JPEGFile jpeg = new JPEGFile(in);
    in.mark();
    try {
        outer: while (true) {
            int reclen;
            int segID = jpeg.readMarkerSegment();
            if (log.isTraceEnabled()) {
                log.trace("Seg Marker: " + Integer.toHexString(segID));
            }
            switch (segID) {
            case EOI:
                log.trace("EOI found. Stopping.");
                break outer;
            case SOS:
                log.trace("SOS found. Stopping early."); //TODO Not sure if this is safe
                break outer;
            case SOI:
            case NULL:
                break;
            case SOF0: //baseline
            case SOF1: //extended sequential DCT
            case SOF2: //progressive (since PDF 1.3)
            case SOFA: //progressive (since PDF 1.3)
                sofType = segID;
                if (log.isTraceEnabled()) {
                    log.trace("SOF: " + Integer.toHexString(sofType));
                }
                in.mark();
                try {
                    reclen = jpeg.readSegmentLength();
                    in.skipBytes(1); //data precision
                    in.skipBytes(2); //height
                    in.skipBytes(2); //width
                    int numComponents = in.readUnsignedByte();
                    if (numComponents == 1) {
                        colorSpace = ColorSpace.getInstance(ColorSpace.CS_GRAY);
                    } else if (numComponents == 3) {
                        colorSpace = ColorSpace.getInstance(ColorSpace.CS_LINEAR_RGB);
                    } else if (numComponents == 4) {
                        colorSpace = DeviceCMYKColorSpace.getInstance();
                    } else {
                        throw new ImageException("Unsupported ColorSpace for image " + info
                                + ". The number of components supported are 1, 3 and 4.");
                    }
                } finally {
                    in.reset();
                }
                in.skipBytes(reclen);
                break;
            case APP2: //ICC (see ICC1V42.pdf)
                in.mark();
                try {
                    reclen = jpeg.readSegmentLength();
                    // Check for ICC profile
                    byte[] iccString = new byte[11];
                    in.readFully(iccString);
                    in.skipBytes(1); //string terminator (null byte)

                    if ("ICC_PROFILE".equals(new String(iccString, "US-ASCII"))) {
                        in.skipBytes(2); //chunk sequence number and total number of chunks
                        int payloadSize = reclen - 2 - 12 - 2;
                        if (ignoreColorProfile(hints)) {
                            log.debug("Ignoring ICC profile data in JPEG");
                            in.skipBytes(payloadSize);
                        } else {
                            byte[] buf = new byte[payloadSize];
                            in.readFully(buf);
                            if (iccStream == null) {
                                if (log.isDebugEnabled()) {
                                    log.debug("JPEG has an ICC profile");
                                    DataInputStream din = new DataInputStream(new ByteArrayInputStream(buf));
                                    log.debug("Declared ICC profile size: " + din.readInt());
                                }
                                //ICC profiles can be split into several chunks
                                //so collect in a byte array output stream
                                iccStream = new ByteArrayOutputStream();
                            }
                            iccStream.write(buf);
                        }
                    }
                } finally {
                    in.reset();
                }
                in.skipBytes(reclen);
                break;
            case APPE: //Adobe-specific (see 5116.DCT_Filter.pdf)
                in.mark();
                try {
                    reclen = jpeg.readSegmentLength();
                    // Check for Adobe header
                    byte[] adobeHeader = new byte[5];
                    in.readFully(adobeHeader);

                    if ("Adobe".equals(new String(adobeHeader, "US-ASCII"))) {
                        // The reason for reading the APPE marker is that Adobe Photoshop
                        // generates CMYK JPEGs with inverted values. The correct thing
                        // to do would be to interpret the values in the marker, but for now
                        // only assume that if APPE marker is present and colorspace is CMYK,
                        // the image is inverted.
                        appeFound = true;
                    }
                } finally {
                    in.reset();
                }
                in.skipBytes(reclen);
                break;
            default:
                jpeg.skipCurrentMarkerSegment();
            }
        }
    } finally {
        in.reset();
    }

    ICC_Profile iccProfile = buildICCProfile(info, colorSpace, iccStream);
    if (iccProfile == null && colorSpace == null) {
        throw new ImageException("ColorSpace could not be identified for JPEG image " + info);
    }

    boolean invertImage = false;
    if (appeFound && colorSpace.getType() == ColorSpace.TYPE_CMYK) {
        if (log.isDebugEnabled()) {
            log.debug("JPEG has an Adobe APPE marker. Note: CMYK Image will be inverted. ("
                    + info.getOriginalURI() + ")");
        }
        invertImage = true;
    }

    ImageRawJPEG rawImage = new ImageRawJPEG(info, ImageUtil.needInputStream(src), sofType, colorSpace,
            iccProfile, invertImage);
    return rawImage;
}