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- /*
- * 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.
- */
-
- /* $Id$ */
-
- package org.apache.fop.fonts.truetype;
-
- import java.io.IOException;
- import java.util.HashSet;
- import java.util.Map;
- import java.util.Set;
- import java.util.TreeSet;
-
- /**
- * This "glyf" table in a TrueType font file contains information that describes the glyphs. This
- * class is responsible for creating a subset of the "glyf" table given a set of glyph indices.
- */
- public class GlyfTable {
-
- private final TTFMtxEntry[] mtxTab;
-
- private final long tableOffset;
-
- private final Set<Long> remappedComposites;
-
- private final Map<Integer, Integer> subset;
-
- private final FontFileReader in;
-
- /** All the composite glyphs that appear in the subset. */
- private Set<Integer> compositeGlyphs = new TreeSet<Integer>();
-
- /** All the glyphs that are composed, but do not appear in the subset. */
- private Set<Integer> composedGlyphs = new TreeSet<Integer>();
-
- GlyfTable(FontFileReader in, TTFMtxEntry[] metrics, TTFDirTabEntry dirTableEntry,
- Map<Integer, Integer> glyphs) throws IOException {
- mtxTab = metrics;
- tableOffset = dirTableEntry.getOffset();
- remappedComposites = new HashSet<Long>();
- this.subset = glyphs;
- this.in = in;
- }
-
- private static enum GlyfFlags {
-
- ARG_1_AND_2_ARE_WORDS(4, 2),
- ARGS_ARE_XY_VALUES,
- ROUND_XY_TO_GRID,
- WE_HAVE_A_SCALE(2),
- RESERVED,
- MORE_COMPONENTS,
- WE_HAVE_AN_X_AND_Y_SCALE(4),
- WE_HAVE_A_TWO_BY_TWO(8),
- WE_HAVE_INSTRUCTIONS,
- USE_MY_METRICS,
- OVERLAP_COMPOUND,
- SCALED_COMPONENT_OFFSET,
- UNSCALED_COMPONENT_OFFSET;
-
- private final int bitMask;
- private final int argsCountIfSet;
- private final int argsCountIfNotSet;
-
- private GlyfFlags(int argsCountIfSet, int argsCountIfNotSet) {
- this.bitMask = 1 << this.ordinal();
- this.argsCountIfSet = argsCountIfSet;
- this.argsCountIfNotSet = argsCountIfNotSet;
- }
-
- private GlyfFlags(int argsCountIfSet) {
- this(argsCountIfSet, 0);
- }
-
- private GlyfFlags() {
- this(0, 0);
- }
-
- /**
- * Calculates, from the given flags, the offset to the next glyph index.
- *
- * @param flags the glyph data flags
- * @return offset to the next glyph if any, or 0
- */
- static int getOffsetToNextComposedGlyf(int flags) {
- int offset = 0;
- for (GlyfFlags flag : GlyfFlags.values()) {
- offset += (flags & flag.bitMask) > 0 ? flag.argsCountIfSet : flag.argsCountIfNotSet;
- }
- return offset;
- }
-
- /**
- * Checks the given flags to see if there is another composed glyph.
- *
- * @param flags the glyph data flags
- * @return true if there is another composed glyph, otherwise false.
- */
- static boolean hasMoreComposites(int flags) {
- return (flags & MORE_COMPONENTS.bitMask) > 0;
- }
- }
-
- /**
- * Populates the map of subset glyphs with all the glyphs that compose the glyphs in the subset.
- * This also re-maps the indices of composed glyphs to their new index in the subset font.
- *
- * @throws IOException an I/O error
- */
- void populateGlyphsWithComposites() throws IOException {
- for (int indexInOriginal : subset.keySet()) {
- scanGlyphsRecursively(indexInOriginal);
- }
-
- addAllComposedGlyphsToSubset();
-
- for (int compositeGlyph : compositeGlyphs) {
- long offset = tableOffset + mtxTab[compositeGlyph].getOffset() + 10;
- if (!remappedComposites.contains(offset)) {
- remapComposite(offset);
- }
- }
- }
-
- /**
- * Scans each glyph for any composed glyphs. This populates <code>compositeGlyphs</code> with
- * all the composite glyphs being used in the subset. This also populates <code>newGlyphs</code>
- * with any new glyphs that are composed and do not appear in the subset of glyphs.
- *
- * For example the double quote mark (") is often composed of two apostrophes ('), if an
- * apostrophe doesn't appear in the glyphs in the subset, it will be included and will be added
- * to newGlyphs.
- *
- * @param indexInOriginal the index of the glyph to test from the original font
- * @throws IOException an I/O error
- */
- private void scanGlyphsRecursively(int indexInOriginal) throws IOException {
- if (!subset.containsKey(indexInOriginal)) {
- composedGlyphs.add(indexInOriginal);
- }
-
- if (isComposite(indexInOriginal)) {
- compositeGlyphs.add(indexInOriginal);
- Set<Integer> composedGlyphs = retrieveComposedGlyphs(indexInOriginal);
- for (Integer composedGlyph : composedGlyphs) {
- scanGlyphsRecursively(composedGlyph);
- }
- }
- }
-
- /**
- * Adds to the subset, all the glyphs that are composed by a glyph, but do not appear themselves
- * in the subset.
- */
- private void addAllComposedGlyphsToSubset() {
- int newIndex = subset.size();
- for (int composedGlyph : composedGlyphs) {
- subset.put(composedGlyph, newIndex++);
- }
- }
-
- /**
- * Re-maps the index of composed glyphs in the original font to the index of the same glyph in
- * the subset font.
- *
- * @param glyphOffset the offset of the composite glyph
- * @throws IOException an I/O error
- */
- private void remapComposite(long glyphOffset) throws IOException {
- long currentGlyphOffset = glyphOffset;
-
- remappedComposites.add(currentGlyphOffset);
-
- int flags = 0;
- do {
- flags = in.readTTFUShort(currentGlyphOffset);
- int glyphIndex = in.readTTFUShort(currentGlyphOffset + 2);
- Integer indexInSubset = subset.get(glyphIndex);
- assert indexInSubset != null;
- /*
- * TODO: this should not be done here!! We're writing to the stream we're reading from,
- * this is asking for trouble! What should happen is when the glyph data is copied from
- * subset, the remapping should be done there. So the original stream is left untouched.
- */
- in.writeTTFUShort(currentGlyphOffset + 2, indexInSubset);
-
- currentGlyphOffset += 4 + GlyfFlags.getOffsetToNextComposedGlyf(flags);
- } while (GlyfFlags.hasMoreComposites(flags));
- }
-
- private boolean isComposite(int indexInOriginal) throws IOException {
- int numberOfContours = in.readTTFShort(tableOffset + mtxTab[indexInOriginal].getOffset());
- return numberOfContours < 0;
- }
-
- /**
- * Reads a composite glyph at a given index and retrieves all the glyph indices of contingent
- * composed glyphs.
- *
- * @param indexInOriginal the glyph index of the composite glyph
- * @return the set of glyph indices this glyph composes
- * @throws IOException an I/O error
- */
- private Set<Integer> retrieveComposedGlyphs(int indexInOriginal)
- throws IOException {
- Set<Integer> composedGlyphs = new HashSet<Integer>();
- long offset = tableOffset + mtxTab[indexInOriginal].getOffset() + 10;
- int flags = 0;
- do {
- flags = in.readTTFUShort(offset);
- composedGlyphs.add(in.readTTFUShort(offset + 2));
- offset += 4 + GlyfFlags.getOffsetToNextComposedGlyf(flags);
- } while (GlyfFlags.hasMoreComposites(flags));
-
- return composedGlyphs;
- }
- }
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