/*
* 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;
/**
* A vertical metrics 'vmtx' table in a TrueType or OpenType font.
*
* This table is required by the OpenType CJK Font Guidelines for "all
* OpenType fonts that are used for vertical writing".
*
* This table is specified in both the TrueType and OpenType specifications.
*
* @author Glenn Adams
*
*/
public class VerticalMetricsTable extends TTFTable
{
/**
* A tag that identifies this table type.
*/
public static final String TAG = "vmtx";
private int[] advanceHeight;
private short[] topSideBearing;
private short[] nonVerticalTopSideBearing;
private int numVMetrics;
VerticalMetricsTable(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
public void read(TrueTypeFont ttf, TTFDataStream data) throws IOException
{
VerticalHeaderTable vHeader = ttf.getVerticalHeader();
numVMetrics = vHeader.getNumberOfVMetrics();
int numGlyphs = ttf.getNumberOfGlyphs();
int bytesRead = 0;
advanceHeight = new int[ numVMetrics ];
topSideBearing = new short[ numVMetrics ];
for( int i=0; i<numVMetrics; i++ )
{
advanceHeight[i] = data.readUnsignedShort();
topSideBearing[i] = data.readSignedShort();
bytesRead += 4;
}
if (bytesRead < getLength())
{
int numberNonVertical = numGlyphs - numVMetrics;
// handle bad fonts with too many vmetrics
if (numberNonVertical < 0)
{
numberNonVertical = numGlyphs;
}
nonVerticalTopSideBearing = new short[ numberNonVertical ];
for( int i=0; i<numberNonVertical; i++ )
{
if (bytesRead < getLength())
{
nonVerticalTopSideBearing[i] = data.readSignedShort();
bytesRead += 2;
}
}
}
initialized = true;
}
/**
* Returns the advance height for the given GID.
*
* @param gid GID
*/
public int getAdvanceHeight(int gid)
{
if (gid < numVMetrics)
{
return advanceHeight[gid];
}
else
{
// monospaced fonts may not have a height for every glyph
// the last one is for subsequent glyphs
return advanceHeight[advanceHeight.length -1];
}
}
}