fop/src/sandbox/org/apache/fop/render/afp/modca/ImageSegment.java

/*
 * Copyright 2006 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/* $Id$ */

package org.apache.fop.render.afp.modca;
import java.io.IOException;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;

/**
 * An Image Segment is represented by a set of self-defining fields, fields
 * that describe their own contents.  It starts with a Begin Segment, and
 * ends with an End Segment.
 *
 * Between the Begin Segment and End Segment is the image information to
 * be processed, called the Image Content.
 *
 * Only one Image Content can exist within a single IOCA Image Segment.
 */
public class ImageSegment extends AbstractAFPObject {

    /**
     * Default name for the object environment group
     */
    private static final String DEFAULT_NAME = "IS01";

    /**
     * The name of the image segment
     */
    private String _name;

    /**
     * The name of the image segment as EBCIDIC bytes
     */
    private byte[] _nameBytes;

    /**
     * The ImageContent for the image segment
     */
    private ImageContent _imageContent = null;

    /**
     * Default constructor for the ImageSegment.
     */
    public ImageSegment() {

        this(DEFAULT_NAME);

    }

    /**
     * Constructor for the image segment with the specified name,
     * the name must be a fixed length of eight characters.
     * @param name	The name of the image.
     */
    public ImageSegment(String name) {

        if (name.length() != 4) {
            String msg = "Image segment name must be 4 characters long " + name;
            log.error("Constructor:: " + msg);
            throw new IllegalArgumentException(msg);
        }

        _name = name;

        try {

            _nameBytes = name.getBytes(AFPConstants.EBCIDIC_ENCODING);

        } catch (UnsupportedEncodingException usee) {

            _nameBytes = name.getBytes();
            log.warn(
                "Constructor:: UnsupportedEncodingException translating the name "
                + name);

        }

    }

    /**
     * Sets the image size parameters
     * resolution, hsize and vsize.
     * @param hresol The horizontal resolution of the image.
     * @param vresol The vertical resolution of the image.
     * @param hsize The horizontal size of the image.
     * @param vsize The vertival size of the image.
     */
    public void setImageSize(int hresol, int vresol, int hsize, int vsize) {
        if (_imageContent == null) {
            _imageContent = new ImageContent();
        }
        _imageContent.setImageSize(hresol, vresol, hsize, vsize);
    }

    /**
     * Sets the image encoding.
     * @param encoding The image encoding.
     */
    public void setImageEncoding(byte encoding) {
        if (_imageContent == null) {
            _imageContent = new ImageContent();
        }
        _imageContent.setImageEncoding(encoding);
    }

    /**
     * Sets the image compression.
     * @param compression The image compression.
     */
    public void setImageCompression(byte compression) {
        if (_imageContent == null) {
            _imageContent = new ImageContent();
        }
        _imageContent.setImageCompression(compression);
    }

    /**
     * Sets the image IDE size.
     * @param size The IDE size.
     */
    public void setImageIDESize(byte size) {
        if (_imageContent == null) {
            _imageContent = new ImageContent();
        }
        _imageContent.setImageIDESize(size);
    }

    /**
     * Sets the image IDE color model.
     * @param size The IDE color model.
     */
    public void setImageIDEColorModel(byte colorModel) {
        if (_imageContent == null) {
            _imageContent = new ImageContent();
        }
        _imageContent.setImageIDEColorModel(colorModel);
    }

    /**
     * Set the data of the image.
     * @param data the image data
     */
    public void setImageData(byte data[]) {
        if (_imageContent == null) {
            _imageContent = new ImageContent();
        }
        _imageContent.setImageData(data);
    }

    /**
     * Accessor method to write the AFP datastream for the Image Segment
     * @param os The stream to write to
     * @throws java.io.IOException
     */
    public void writeDataStream(OutputStream os)
        throws IOException {

        writeStart(os);

        if (_imageContent != null) {
            _imageContent.writeDataStream(os);
        }

        writeEnd(os);

    }

    /**
     * Helper method to write the start of the Image Segment.
     * @param os The stream to write to
     */
    private void writeStart(OutputStream os)
        throws IOException {

        byte[] data = new byte[] {
            0x70, // ID
            0x04, // Length
            0x00, // Name byte 1
            0x00, // Name byte 2
            0x00, // Name byte 3
            0x00, // Name byte 4
        };

        for (int i = 0; i < _nameBytes.length; i++) {

            data[2 + i] = _nameBytes[i];

        }

        os.write(data);

    }

    /**
     * Helper method to write the end of the Image Segment.
     * @param os The stream to write to
     */
    private void writeEnd(OutputStream os)
        throws IOException {

        byte[] data = new byte[] {
            0x71, // ID
            0x00, // Length
        };

        os.write(data);

    }

}