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/*
* 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.
*/
/* $Id$ */
package org.apache.fop.afp.modca;
import java.io.IOException;
import java.io.OutputStream;
import org.apache.commons.io.output.ByteArrayOutputStream;
import org.apache.fop.afp.ptoca.PtocaConstants;
import org.apache.fop.afp.util.BinaryUtils;
/**
* Presentation text data contains the graphic characters and the control
* sequences necessary to position the characters within the object space. The
* data consists of: - graphic characters to be presented - control sequences
* that position them - modal control sequences that adjust the positions by
* small amounts - other functions causing text to be presented with differences
* in appearance.
* <p>
* The graphic characters are expected to conform to a coded font representation
* so that they can be translated from the code point in the object data to the
* character in the coded font. The units of measure for linear displacements
* are derived from the PresentationTextDescriptor or from the hierarchical
* defaults.
* <p>
* In addition to graphic character code points, Presentation Text data can
* contain embedded control sequences. These are strings of two or more bytes
* which signal an alternate mode of processing for the content of the current
* Presentation Text data.
* <p>
* The content for this object can be created using {@link PtocaBuilder}.
*/
public class PresentationTextData extends AbstractAFPObject implements PtocaConstants {
/** the maximum size of the presentation text data.*/
private static final int MAX_SIZE = 8192;
/** the AFP data relating to this presentation text data. */
private final ByteArrayOutputStream baos = new ByteArrayOutputStream();
/**
* Default constructor for the PresentationTextData.
*/
public PresentationTextData() {
this(false);
}
private static final int HEADER_LENGTH = 9;
/**
* Constructor for the PresentationTextData, the boolean flag indicate
* whether the control sequence prefix should be set to indicate the start
* of a new control sequence.
*
* @param controlInd
* The control sequence indicator.
*/
public PresentationTextData(boolean controlInd) {
final byte[] data = {
0x5A, // Structured field identifier
0x00, // Record length byte 1
0x00, // Record length byte 2
SF_CLASS, // PresentationTextData identifier byte 1
Type.DATA, // PresentationTextData identifier byte 2
Category.PRESENTATION_TEXT, // PresentationTextData identifier byte 3
0x00, // Flag
0x00, // Reserved
0x00, // Reserved
};
baos.write(data, 0, HEADER_LENGTH);
if (controlInd) {
baos.write(new byte[] {0x2B, (byte) 0xD3}, 0, 2);
}
}
/**
* Returns the number of data bytes still available in this object until it is full and a new
* one has to be started.
* @return the number of data bytes available
*/
public int getBytesAvailable() {
return MAX_SIZE - baos.size() + HEADER_LENGTH;
}
/**
* Returns the output stream the content data is written to.
* @return the output stream
*/
protected OutputStream getOutputStream() {
return this.baos;
}
/** {@inheritDoc} */
public void writeToStream(OutputStream os) throws IOException {
assert getBytesAvailable() >= 0;
byte[] data = baos.toByteArray();
byte[] size = BinaryUtils.convert(data.length - 1, 2);
data[1] = size[0];
data[2] = size[1];
os.write(data);
}
}
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