org.apache.fontbox.ttf.GlyphTable 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;
/**
* A table in a true type font.
*
* @author Ben Litchfield
*/
public class GlyphTable extends TTFTable
{
/**
* Tag to identify this table.
*/
public static final String TAG = "glyf";
private GlyphData[] glyphs;
// lazy table reading
private TTFDataStream data;
private IndexToLocationTable loca;
private int numGlyphs;
private int cached = 0;
/**
* Don't even bother to cache huge fonts.
*/
private static final int MAX_CACHE_SIZE = 5000;
/**
* Don't cache more glyphs than this.
*/
private static final int MAX_CACHED_GLYPHS = 100;
GlyphTable(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
{
loca = ttf.getIndexToLocation();
numGlyphs = ttf.getNumberOfGlyphs();
if (numGlyphs < MAX_CACHE_SIZE)
{
// don't cache the huge fonts to save memory
glyphs = new GlyphData[numGlyphs];
}
// we don't actually read the complete table here because it can contain tens of thousands of glyphs
this.data = data;
initialized = true;
}
/**
* Returns all glyphs. This method can be very slow.
*
* @throws IOException If there is an error reading the data.
*/
public GlyphData[] getGlyphs() throws IOException
{
// PDFBOX-4219: synchronize on data because it is accessed by several threads
// when PDFBox is accessing a standard 14 font for the first time
synchronized (data)
{
// the glyph offsets
long[] offsets = loca.getOffsets();
// the end of the glyph table
// should not be 0, but sometimes is, see PDFBOX-2044
// structure of this table: see
// https://developer.apple.com/fonts/TTRefMan/RM06/Chap6loca.html
long endOfGlyphs = offsets[numGlyphs];
long offset = getOffset();
if (glyphs == null)
{
glyphs = new GlyphData[numGlyphs];
}
for (int gid = 0; gid < numGlyphs; gid++)
{
// end of glyphs reached?
if (endOfGlyphs != 0 && endOfGlyphs == offsets[gid])
{
break;
}
// the current glyph isn't defined
// if the next offset is equal or smaller to the current offset
if (offsets[gid + 1] <= offsets[gid])
{
continue;
}
if (glyphs[gid] != null)
{
// already cached
continue;
}
data.seek(offset + offsets[gid]);
if (glyphs[gid] == null)
{
++cached;
}
glyphs[gid] = getGlyphData(gid);
}
initialized = true;
return glyphs;
}
}
/**
* @param glyphsValue The glyphs to set.
*/
public void setGlyphs(GlyphData[] glyphsValue)
{
glyphs = glyphsValue;
}
/**
* Returns the data for the glyph with the given GID.
*
* @param gid GID
* @throws IOException if the font cannot be read
*/
public GlyphData getGlyph(int gid) throws IOException
{
if (gid < 0 || gid >= numGlyphs)
{
return null;
}
if (glyphs != null && glyphs[gid] != null)
{
return glyphs[gid];
}
// PDFBOX-4219: synchronize on data because it is accessed by several threads
// when PDFBox is accessing a standard 14 font for the first time
synchronized (data)
{
// read a single glyph
long[] offsets = loca.getOffsets();
if (offsets[gid] == offsets[gid + 1])
{
// no outline
return null;
}
// save
long currentPosition = data.getCurrentPosition();
data.seek(getOffset() + offsets[gid]);
GlyphData glyph = getGlyphData(gid);
// restore
data.seek(currentPosition);
if (glyphs != null && glyphs[gid] == null && cached < MAX_CACHED_GLYPHS)
{
glyphs[gid] = glyph;
++cached;
}
return glyph;
}
}
private GlyphData getGlyphData(int gid) throws IOException
{
GlyphData glyph = new GlyphData();
HorizontalMetricsTable hmt = font.getHorizontalMetrics();
int leftSideBearing = hmt == null ? 0 : hmt.getLeftSideBearing(gid);
glyph.initData(this, data, leftSideBearing);
// resolve composite glyph
if (glyph.getDescription().isComposite())
{
glyph.getDescription().resolve();
}
return glyph;
}
}