http://xmlgraphics.apache.org/fop/: Apache FOP (Formatting Objects Processor) is the world's first print formatter driven by XSL formatting objects (XSL-FO) and the world's first output independent formatter. It is a Java application that reads a formatting object (FO) tree and renders the resulting pages to a specified output. Output formats currently supported include PDF, PCL, PS, AFP, TIFF, PNG, SVG, XML (area tree representation), Print, AWT and TXT. The primary output target is PDF. (Apache Software Foundation) 
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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: PageDescriptor.java 1297404 2012-03-06 10:17:54Z vhennebert $ */

package org.apache.fop.afp.modca;

import java.io.IOException;
import java.io.OutputStream;

import org.apache.fop.afp.util.BinaryUtils;


The Page Descriptor structured field specifies the size and attributes of
a page or overlay presentation space.

/**
 * The Page Descriptor structured field specifies the size and attributes of
 * a page or overlay presentation space.
 *
 */
public class PageDescriptor extends AbstractDescriptor {

    
Construct a page descriptor for the specified page width
and page height.

Params:
  • width – The page width.
  • height – The page height.
  • widthRes – The page width resolution
  • heightRes – The page height resolution
/**
     * Construct a page descriptor for the specified page width
     * and page height.
     *
     * @param width The page width.
     * @param height The page height.
     * @param widthRes The page width resolution
     * @param heightRes The page height resolution
     */
    public PageDescriptor(int width, int height, int widthRes, int heightRes) {
        super(width, height, widthRes, heightRes);
    }

    
{@inheritDoc} 
/** {@inheritDoc} */
    public void writeToStream(OutputStream os) throws IOException {
        byte[] data = new byte[24];
        copySF(data, Type.DESCRIPTOR, Category.PAGE);
        data[2] = 0x17;

        // XpgBase
        data[9] = 0x00; // XpgBase = 10 inches

        // YpgBase
        data[10] = 0x00; // YpgBase = 10 inches

        // XpgUnits
        byte[] xdpi = BinaryUtils.convert(widthRes * 10, 2);
        data[11] = xdpi[0];
        data[12] = xdpi[1];

        // YpgUnits
        byte[] ydpi = BinaryUtils.convert(heightRes * 10, 2);
        data[13] = ydpi[0];
        data[14] = ydpi[1];

        // XpgSize
        byte[] x = BinaryUtils.convert(width, 3);
        data[15] = x[0];
        data[16] = x[1];
        data[17] = x[2];

        // YpgSize
        byte[] y = BinaryUtils.convert(height, 3);
        data[18] = y[0];
        data[19] = y[1];
        data[20] = y[2];

        data[21] = 0x00; // Reserved
        data[22] = 0x00; // Reserved
        data[23] = 0x00; // Reserved

        os.write(data);
    }

}