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iText, a free Java-PDF library
/*
* $Id: TrueTypeFontSubSet.java 3427 2008-05-24 18:32:31Z xlv $
*
* Copyright 2001, 2002 Paulo Soares
*
* 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, 2000, 2001, 2002 by Bruno Lowagie.
* All Rights Reserved.
* Co-Developer of the code is Paulo Soares. Portions created by the Co-Developer
* are Copyright (C) 2000, 2001, 2002 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
* allow use of your version of this file only under the terms of the LGPL
* License and not to allow others to use your version of this file under
* 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
* you aren't using an obsolete version:
* http://www.lowagie.com/iText/
*/
package com.lowagie.text.pdf;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import com.lowagie.text.DocumentException;
import com.lowagie.text.ExceptionConverter;
/** Subsets a True Type font by removing the unneeded glyphs from
* the font.
*
* @author Paulo Soares ([email protected])
*/
class TrueTypeFontSubSet {
static final String tableNamesSimple[] = {"cvt ", "fpgm", "glyf", "head",
"hhea", "hmtx", "loca", "maxp", "prep"};
static final String tableNamesCmap[] = {"cmap", "cvt ", "fpgm", "glyf", "head",
"hhea", "hmtx", "loca", "maxp", "prep"};
static final String tableNamesExtra[] = {"OS/2", "cmap", "cvt ", "fpgm", "glyf", "head",
"hhea", "hmtx", "loca", "maxp", "name, prep"};
static final int entrySelectors[] = {0,0,1,1,2,2,2,2,3,3,3,3,3,3,3,3,4,4,4,4,4};
static final int TABLE_CHECKSUM = 0;
static final int TABLE_OFFSET = 1;
static final int TABLE_LENGTH = 2;
static final int HEAD_LOCA_FORMAT_OFFSET = 51;
static final int ARG_1_AND_2_ARE_WORDS = 1;
static final int WE_HAVE_A_SCALE = 8;
static final int MORE_COMPONENTS = 32;
static final int WE_HAVE_AN_X_AND_Y_SCALE = 64;
static final int WE_HAVE_A_TWO_BY_TWO = 128;
/** Contains the location of the several tables. The key is the name of
* the table and the value is an int[3] where position 0
* is the checksum, position 1 is the offset from the start of the file
* and position 2 is the length of the table.
*/
protected HashMap tableDirectory;
/** The file in use.
*/
protected RandomAccessFileOrArray rf;
/** The file name.
*/
protected String fileName;
protected boolean includeCmap;
protected boolean includeExtras;
protected boolean locaShortTable;
protected int locaTable[];
protected HashMap glyphsUsed;
protected ArrayList glyphsInList;
protected int tableGlyphOffset;
protected int newLocaTable[];
protected byte newLocaTableOut[];
protected byte newGlyfTable[];
protected int glyfTableRealSize;
protected int locaTableRealSize;
protected byte outFont[];
protected int fontPtr;
protected int directoryOffset;
/** Creates a new TrueTypeFontSubSet
* @param directoryOffset The offset from the start of the file to the table directory
* @param fileName the file name of the font
* @param glyphsUsed the glyphs used
* @param includeCmap true if the table cmap is to be included in the generated font
*/
TrueTypeFontSubSet(String fileName, RandomAccessFileOrArray rf, HashMap glyphsUsed, int directoryOffset, boolean includeCmap, boolean includeExtras) {
this.fileName = fileName;
this.rf = rf;
this.glyphsUsed = glyphsUsed;
this.includeCmap = includeCmap;
this.includeExtras = includeExtras;
this.directoryOffset = directoryOffset;
glyphsInList = new ArrayList(glyphsUsed.keySet());
}
/** Does the actual work of subsetting the font.
* @throws IOException on error
* @throws DocumentException on error
* @return the subset font
*/
byte[] process() throws IOException, DocumentException {
try {
rf.reOpen();
createTableDirectory();
readLoca();
flatGlyphs();
createNewGlyphTables();
locaTobytes();
assembleFont();
return outFont;
}
finally {
try {
rf.close();
}
catch (Exception e) {
// empty on purpose
}
}
}
protected void assembleFont() throws IOException {
int tableLocation[];
int fullFontSize = 0;
String tableNames[];
if (includeExtras)
tableNames = tableNamesExtra;
else {
if (includeCmap)
tableNames = tableNamesCmap;
else
tableNames = tableNamesSimple;
}
int tablesUsed = 2;
int len = 0;
for (int k = 0; k < tableNames.length; ++k) {
String name = tableNames[k];
if (name.equals("glyf") || name.equals("loca"))
continue;
tableLocation = (int[])tableDirectory.get(name);
if (tableLocation == null)
continue;
++tablesUsed;
fullFontSize += (tableLocation[TABLE_LENGTH] + 3) & (~3);
}
fullFontSize += newLocaTableOut.length;
fullFontSize += newGlyfTable.length;
int ref = 16 * tablesUsed + 12;
fullFontSize += ref;
outFont = new byte[fullFontSize];
fontPtr = 0;
writeFontInt(0x00010000);
writeFontShort(tablesUsed);
int selector = entrySelectors[tablesUsed];
writeFontShort((1 << selector) * 16);
writeFontShort(selector);
writeFontShort((tablesUsed - (1 << selector)) * 16);
for (int k = 0; k < tableNames.length; ++k) {
String name = tableNames[k];
tableLocation = (int[])tableDirectory.get(name);
if (tableLocation == null)
continue;
writeFontString(name);
if (name.equals("glyf")) {
writeFontInt(calculateChecksum(newGlyfTable));
len = glyfTableRealSize;
}
else if (name.equals("loca")) {
writeFontInt(calculateChecksum(newLocaTableOut));
len = locaTableRealSize;
}
else {
writeFontInt(tableLocation[TABLE_CHECKSUM]);
len = tableLocation[TABLE_LENGTH];
}
writeFontInt(ref);
writeFontInt(len);
ref += (len + 3) & (~3);
}
for (int k = 0; k < tableNames.length; ++k) {
String name = tableNames[k];
tableLocation = (int[])tableDirectory.get(name);
if (tableLocation == null)
continue;
if (name.equals("glyf")) {
System.arraycopy(newGlyfTable, 0, outFont, fontPtr, newGlyfTable.length);
fontPtr += newGlyfTable.length;
newGlyfTable = null;
}
else if (name.equals("loca")) {
System.arraycopy(newLocaTableOut, 0, outFont, fontPtr, newLocaTableOut.length);
fontPtr += newLocaTableOut.length;
newLocaTableOut = null;
}
else {
rf.seek(tableLocation[TABLE_OFFSET]);
rf.readFully(outFont, fontPtr, tableLocation[TABLE_LENGTH]);
fontPtr += (tableLocation[TABLE_LENGTH] + 3) & (~3);
}
}
}
protected void createTableDirectory() throws IOException, DocumentException {
tableDirectory = new HashMap();
rf.seek(directoryOffset);
int id = rf.readInt();
if (id != 0x00010000)
throw new DocumentException(fileName + " is not a true type file.");
int num_tables = rf.readUnsignedShort();
rf.skipBytes(6);
for (int k = 0; k < num_tables; ++k) {
String tag = readStandardString(4);
int tableLocation[] = new int[3];
tableLocation[TABLE_CHECKSUM] = rf.readInt();
tableLocation[TABLE_OFFSET] = rf.readInt();
tableLocation[TABLE_LENGTH] = rf.readInt();
tableDirectory.put(tag, tableLocation);
}
}
protected void readLoca() throws IOException, DocumentException {
int tableLocation[];
tableLocation = (int[])tableDirectory.get("head");
if (tableLocation == null)
throw new DocumentException("Table 'head' does not exist in " + fileName);
rf.seek(tableLocation[TABLE_OFFSET] + HEAD_LOCA_FORMAT_OFFSET);
locaShortTable = (rf.readUnsignedShort() == 0);
tableLocation = (int[])tableDirectory.get("loca");
if (tableLocation == null)
throw new DocumentException("Table 'loca' does not exist in " + fileName);
rf.seek(tableLocation[TABLE_OFFSET]);
if (locaShortTable) {
int entries = tableLocation[TABLE_LENGTH] / 2;
locaTable = new int[entries];
for (int k = 0; k < entries; ++k)
locaTable[k] = rf.readUnsignedShort() * 2;
}
else {
int entries = tableLocation[TABLE_LENGTH] / 4;
locaTable = new int[entries];
for (int k = 0; k < entries; ++k)
locaTable[k] = rf.readInt();
}
}
protected void createNewGlyphTables() throws IOException {
newLocaTable = new int[locaTable.length];
int activeGlyphs[] = new int[glyphsInList.size()];
for (int k = 0; k < activeGlyphs.length; ++k)
activeGlyphs[k] = ((Integer)glyphsInList.get(k)).intValue();
Arrays.sort(activeGlyphs);
int glyfSize = 0;
for (int k = 0; k < activeGlyphs.length; ++k) {
int glyph = activeGlyphs[k];
glyfSize += locaTable[glyph + 1] - locaTable[glyph];
}
glyfTableRealSize = glyfSize;
glyfSize = (glyfSize + 3) & (~3);
newGlyfTable = new byte[glyfSize];
int glyfPtr = 0;
int listGlyf = 0;
for (int k = 0; k < newLocaTable.length; ++k) {
newLocaTable[k] = glyfPtr;
if (listGlyf < activeGlyphs.length && activeGlyphs[listGlyf] == k) {
++listGlyf;
newLocaTable[k] = glyfPtr;
int start = locaTable[k];
int len = locaTable[k + 1] - start;
if (len > 0) {
rf.seek(tableGlyphOffset + start);
rf.readFully(newGlyfTable, glyfPtr, len);
glyfPtr += len;
}
}
}
}
protected void locaTobytes() {
if (locaShortTable)
locaTableRealSize = newLocaTable.length * 2;
else
locaTableRealSize = newLocaTable.length * 4;
newLocaTableOut = new byte[(locaTableRealSize + 3) & (~3)];
outFont = newLocaTableOut;
fontPtr = 0;
for (int k = 0; k < newLocaTable.length; ++k) {
if (locaShortTable)
writeFontShort(newLocaTable[k] / 2);
else
writeFontInt(newLocaTable[k]);
}
}
protected void flatGlyphs() throws IOException, DocumentException {
int tableLocation[];
tableLocation = (int[])tableDirectory.get("glyf");
if (tableLocation == null)
throw new DocumentException("Table 'glyf' does not exist in " + fileName);
Integer glyph0 = new Integer(0);
if (!glyphsUsed.containsKey(glyph0)) {
glyphsUsed.put(glyph0, null);
glyphsInList.add(glyph0);
}
tableGlyphOffset = tableLocation[TABLE_OFFSET];
for (int k = 0; k < glyphsInList.size(); ++k) {
int glyph = ((Integer)glyphsInList.get(k)).intValue();
checkGlyphComposite(glyph);
}
}
protected void checkGlyphComposite(int glyph) throws IOException {
int start = locaTable[glyph];
if (start == locaTable[glyph + 1]) // no contour
return;
rf.seek(tableGlyphOffset + start);
int numContours = rf.readShort();
if (numContours >= 0)
return;
rf.skipBytes(8);
for(;;) {
int flags = rf.readUnsignedShort();
Integer cGlyph = new Integer(rf.readUnsignedShort());
if (!glyphsUsed.containsKey(cGlyph)) {
glyphsUsed.put(cGlyph, null);
glyphsInList.add(cGlyph);
}
if ((flags & MORE_COMPONENTS) == 0)
return;
int skip;
if ((flags & ARG_1_AND_2_ARE_WORDS) != 0)
skip = 4;
else
skip = 2;
if ((flags & WE_HAVE_A_SCALE) != 0)
skip += 2;
else if ((flags & WE_HAVE_AN_X_AND_Y_SCALE) != 0)
skip += 4;
if ((flags & WE_HAVE_A_TWO_BY_TWO) != 0)
skip += 8;
rf.skipBytes(skip);
}
}
/** Reads a String from the font file as bytes using the Cp1252
* encoding.
* @param length the length of bytes to read
* @return the String read
* @throws IOException the font file could not be read
*/
protected String readStandardString(int length) throws IOException {
byte buf[] = new byte[length];
rf.readFully(buf);
try {
return new String(buf, BaseFont.WINANSI);
}
catch (Exception e) {
throw new ExceptionConverter(e);
}
}
protected void writeFontShort(int n) {
outFont[fontPtr++] = (byte)(n >> 8);
outFont[fontPtr++] = (byte)(n);
}
protected void writeFontInt(int n) {
outFont[fontPtr++] = (byte)(n >> 24);
outFont[fontPtr++] = (byte)(n >> 16);
outFont[fontPtr++] = (byte)(n >> 8);
outFont[fontPtr++] = (byte)(n);
}
protected void writeFontString(String s) {
byte b[] = PdfEncodings.convertToBytes(s, BaseFont.WINANSI);
System.arraycopy(b, 0, outFont, fontPtr, b.length);
fontPtr += b.length;
}
protected int calculateChecksum(byte b[]) {
int len = b.length / 4;
int v0 = 0;
int v1 = 0;
int v2 = 0;
int v3 = 0;
int ptr = 0;
for (int k = 0; k < len; ++k) {
v3 += b[ptr++] & 0xff;
v2 += b[ptr++] & 0xff;
v1 += b[ptr++] & 0xff;
v0 += b[ptr++] & 0xff;
}
return v0 + (v1 << 8) + (v2 << 16) + (v3 << 24);
}
}