com.lowagie.text.pdf.CMapAwareDocumentFont Maven / Gradle / Ivy
/*
* Copyright 2008 by Kevin Day.
*
* The contents of this file are subject to the Mozilla Public License Version 1.1
* (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.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the License.
*
* The Original Code is 'iText, a free JAVA-PDF library'.
*
* The Initial Developer of the Original Code is Bruno Lowagie. Portions created by
* the Initial Developer are Copyright (C) 1999-2008 by Bruno Lowagie.
* All Rights Reserved.
* Co-Developer of the code is Paulo Soares. Portions created by the Co-Developer
* are Copyright (C) 2000-2008 by Paulo Soares. All Rights Reserved.
*
* Contributor(s): all the names of the contributors are added in the source code
* where applicable.
*
* Alternatively, the contents of this file may be used under the terms of the
* LGPL license (the "GNU LIBRARY GENERAL PUBLIC LICENSE"), in which case the
* provisions of LGPL are applicable instead of those above. If you wish to
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* the MPL, indicate your decision by deleting the provisions above and
* replace them with the notice and other provisions required by the LGPL.
* If you do not delete the provisions above, a recipient may use your version
* of this file under either the MPL or the GNU LIBRARY GENERAL PUBLIC LICENSE.
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the MPL as stated above or under the terms of the GNU
* Library General Public License as published by the Free Software Foundation;
* either version 2 of the License, or any later version.
*
* This library is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU Library general Public License for more
* details.
*
* If you didn't download this code from the following link, you should check if
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* http://www.lowagie.com/iText/
*/
package com.lowagie.text.pdf;
import com.lowagie.text.error_messages.MessageLocalization;
import com.lowagie.text.pdf.fonts.cmaps.CMap;
import com.lowagie.text.pdf.fonts.cmaps.CMapParser;
import java.io.ByteArrayInputStream;
import java.io.IOException;
/**
* Implementation of DocumentFont used while parsing PDF streams.
*
* @since 2.1.4
*/
public class CMapAwareDocumentFont extends DocumentFont {
/** The font dictionary. */
private PdfDictionary fontDic;
/** the width of a space for this font, in normalized 1000 point units */
private int spaceWidth;
/**
* The CMap constructed from the ToUnicode map from the font's dictionary,
* if present. This CMap transforms CID values into unicode equivalent
*/
private CMap toUnicodeCmap;
/**
* Mapping between CID code (single byte only for now) and unicode
* equivalent as derived by the font's encoding. Only needed if the
* ToUnicode CMap is not provided.
*/
private char[] cidbyte2uni;
/**
* Creates an instance of a CMapAwareFont based on an indirect reference to
* a font.
*
* @param refFont
* the indirect reference to a font
*/
public CMapAwareDocumentFont(PRIndirectReference refFont) {
super(refFont);
fontDic = (PdfDictionary) PdfReader.getPdfObjectRelease(refFont);
processToUnicode();
if (toUnicodeCmap == null) {
processUni2Byte();
}
spaceWidth = super.getWidth(' ');
if (spaceWidth == 0) {
spaceWidth = computeAverageWidth();
}
}
/**
* Parses the ToUnicode entry, if present, and constructs a CMap for it
*
* @since 2.1.7
*/
private void processToUnicode() {
PdfObject toUni = fontDic.get(PdfName.TOUNICODE);
if (toUni != null) {
try {
byte[] touni = PdfReader.getStreamBytes((PRStream) PdfReader
.getPdfObjectRelease(toUni));
CMapParser cmapParser = new CMapParser();
toUnicodeCmap = cmapParser
.parse(new ByteArrayInputStream(touni));
} catch (IOException e) {
throw new Error("Unable to process ToUnicode map - "
+ e.getMessage(), e);
}
}
}
/**
* Inverts DocumentFont's uni2byte mapping to obtain a cid-to-unicode
* mapping based on the font's encoding
*
* @since 2.1.7
*/
private void processUni2Byte() {
IntHashtable uni2byte = getUni2Byte();
int e[] = uni2byte.toOrderedKeys();
cidbyte2uni = new char[256];
for (int element : e) {
int n = uni2byte.get(element);
// this is messy, messy - an encoding can have multiple unicode
// values mapping to the same cid - we are going to arbitrarily
// choose the first one
// what we really need to do is to parse the encoding, and handle
// the differences info ourselves. This is a huge duplication of
// code of what is already
// being done in DocumentFont, so I really hate to go down that path
// without seriously thinking about a change in the organization of
// the Font class hierarchy
if (cidbyte2uni[n] == 0) {
cidbyte2uni[n] = (char) element;
}
}
}
/**
* For all widths of all glyphs, compute the average width in normalized
* 1000 point units. This is used to give some meaningful width in cases
* where we need an average font width (such as if the width of a space
* isn't specified by a given font)
*
* @return the average width of all non-zero width glyphs in the font
*/
private int computeAverageWidth() {
int count = 0;
int total = 0;
for (int i = 0; i < super.widths.length; i++) {
if (super.widths[i] != 0) {
total += super.widths[i];
count++;
}
}
return count != 0 ? total / count : 0;
}
/**
* @since 2.1.5 Override to allow special handling for fonts that don't
* specify width of space character
* @see com.lowagie.text.pdf.DocumentFont#getWidth(int)
*/
@Override
public int getWidth(int char1) {
if (char1 == ' ') {
return spaceWidth;
}
return super.getWidth(char1);
}
/**
* Decodes a single CID (represented by one or two bytes) to a unicode
* String.
*
* @param bytes
* the bytes making up the character code to convert
* @param offset
* an offset
* @param len
* a length
* @return a String containing the encoded form of the input bytes using the
* font's encoding.
*/
private String decodeSingleCID(byte[] bytes, int offset, int len) {
if (hasUnicodeCMAP()) {
if (offset + len > bytes.length) {
throw new ArrayIndexOutOfBoundsException(
MessageLocalization.getComposedMessage(
"invalid.index.1", offset + len));
}
return toUnicodeCmap.lookup(bytes, offset, len);
}
if (len == 1) {
return new String(cidbyte2uni, 0xff & bytes[offset], 1);
}
throw new Error("Multi-byte glyphs not implemented yet");
}
/**
* @return true if this font has unicode information available.
*/
public boolean hasUnicodeCMAP() {
return toUnicodeCmap != null;
}
/**
* Decodes a string of bytes (encoded in the font's encoding) into a unicode string. This will
* use the ToUnicode map of the font, if available, otherwise it uses the font's encoding
*
* @param cidbytes
* the bytes that need to be decoded
* @return the unicode String that results from decoding
* @since 2.1.7
*/
public String decode(byte[] cidbytes,
final int offset,
final int len) {
StringBuffer sb = new StringBuffer(); // it's a shame we can't make this
// StringBuilder
for (int i = offset; i < offset + len; i++ ) {
String rslt = decodeSingleCID(cidbytes, i, 1);
if (rslt == null && i + 1 < offset + len) {
rslt = decodeSingleCID(cidbytes, i, 2);
i++ ;
}
if (rslt != null) {
sb.append(rslt);
}
}
return sb.toString();
}
/**
* Decodes a string. This is a normal Java string, but if the range of character values
* exceeds the range of the encoding for the font, this will fail. Required since we need to
* process the characters of strings, and we can't determine the character boundaries in
* advance, especially because of Identity-H encoded fonts which have two-byte character
* indexes.
*
* PdfString is used to hold character code points, even though the bytes may not map 1-1. It's
* not possible to change the encoding once a string is in place.
*
* @param chars
* the Characters that need to be decoded
* @return the unicode String that results from decoding
* @since 2.1.
*/
public String decode(String chars) {
StringBuffer sb = new StringBuffer(); // it's a shame we can't make this
// StringBuilder
for (char c : chars.toCharArray()) {
String result = decode(c);
if (result != null) {
sb.append(result);
}
}
return sb.toString();
}
/**
* Decode single character whose value represents a code point in this font. Will fail if
* the characters do not have values that correspond to valid code points for the font.
* @param c character to decode
* @return Unicode character corresponding to the remapped code according to the font's current encoding.
* @throws Error if the the character is out of range
*/
public String decode(char c) throws Error {
String result;
if (hasUnicodeCMAP()) {
result = toUnicodeCmap.lookup(c);
} else if (c <= 0xff) {
result = new String(cidbyte2uni, 0xff & c, 1);
} else {
throw new Error("Multi-byte glyphs not implemented yet");
}
return result;
}
/**
* Encodes bytes to a String.
*
* @param bytes
* the bytes from a stream
* @param offset
* an offset
* @param len
* a length
* @return a String encoded taking into account if the bytes are in unicode
* or not.
* @deprecated method name is not indicative of what it does. Use
* decode instead.
*/
@Deprecated
public String encode(byte[] bytes, int offset, int len) {
return decode(bytes, offset, len);
}
}
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