org.apache.fontbox.ttf.KerningTable Maven / Gradle / Ivy
/*
* 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.
*/
package org.apache.fontbox.ttf;
import java.io.IOException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* A 'kern' table in a true type font.
*
* @author Glenn Adams
*/
public class KerningTable extends TTFTable
{
private static final Log LOG = LogFactory.getLog(KerningTable.class);
/**
* Tag to identify this table.
*/
public static final String TAG = "kern";
private KerningSubtable[] subtables;
KerningTable(TrueTypeFont font)
{
super(font);
}
/**
* This will read the required data from the stream.
*
* @param ttf The font that is being read.
* @param data The stream to read the data from.
* @throws IOException If there is an error reading the data.
*/
@Override
void read(TrueTypeFont ttf, TTFDataStream data) throws IOException
{
int version = data.readUnsignedShort();
if (version != 0)
{
version = (version << 16) | data.readUnsignedShort();
}
int numSubtables = 0;
if (version == 0)
{
numSubtables = data.readUnsignedShort();
}
else if (version == 1)
{
numSubtables = (int) data.readUnsignedInt();
}
else
{
LOG.debug("Skipped kerning table due to an unsupported kerning table version: " + version);
}
if (numSubtables > 0)
{
subtables = new KerningSubtable[numSubtables];
for (int i = 0; i < numSubtables; ++i)
{
KerningSubtable subtable = new KerningSubtable();
subtable.read(data, version);
subtables[i] = subtable;
}
}
initialized = true;
}
/**
* Obtain first subtable that supports non-cross-stream horizontal kerning.
*
* @return first matching subtable or null if none found
*/
public KerningSubtable getHorizontalKerningSubtable()
{
return getHorizontalKerningSubtable(false);
}
/**
* Obtain first subtable that supports horizontal kerning with specified cross stream.
*
* @param cross true if requesting cross stream horizontal kerning
* @return first matching subtable or null if none found
*/
public KerningSubtable getHorizontalKerningSubtable(boolean cross)
{
if (subtables != null)
{
for (KerningSubtable s : subtables)
{
if (s.isHorizontalKerning(cross))
{
return s;
}
}
}
return null;
}
}