OTF: Support GposLookupType7 format (subtable format 2)

DEVSIX-4631

Author: Snipx

io/src/main/java/com/itextpdf/io/LogMessageConstant.java

@@ -110,6 +110,8 @@ public final class LogMessageConstant {
     public static final String FONT_SUBSET_ISSUE = "Font subset issue. Full font will be embedded.";
     public static final String FORBID_RELEASE_IS_SET = "ForbidRelease flag is set and release is called. Releasing will not be performed.";
     public static final String FORM_FIELD_WAS_FLUSHED = "A form field was flushed. There's no way to create this field in the AcroForm dictionary.";
+    public static final String GPOS_LOOKUP_SUBTABLE_FORMAT_NOT_SUPPORTED =
+            "Subtable format {0} of GPOS Lookup Type {1} is not supported yet";
     public static final String GRAPHICS_STATE_WAS_DELETED = "Graphics state is always deleted after event dispatching. If you want to preserve it in renderer info, use preserveGraphicsState method after receiving renderer info.";
     public static final String IF_PATH_IS_SET_VERTICES_SHALL_NOT_BE_PRESENT = "If Path key is set, Vertices key shall not be present. Remove Vertices key before setting Path";
     public static final String IMAGE_HAS_AMBIGUOUS_SCALE = "The image cannot be auto scaled and scaled by a certain parameter simultaneously";

io/src/main/java/com/itextpdf/io/font/otf/ContextualPositionRule.java

@@ -0,0 +1,36 @@
+/*
+    This file is part of the iText (R) project.
+    Copyright (c) 1998-2020 iText Group NV
+    Authors: iText Software.
+
+    This program is offered under a commercial and under the AGPL license.
+    For commercial licensing, contact us at https://itextpdf.com/sales.  For AGPL licensing, see below.
+
+    AGPL licensing:
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program 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 Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.itextpdf.io.font.otf;
+
+public abstract class ContextualPositionRule extends ContextualRule {
+    private static final long serialVersionUID = 1629646447219066484L;
+
+    /**
+     * Retrieves the position lookup records. Each record specifies a position in the context glyph
+     * sequence and a LookupListIndex to the position lookup that is applied at that position.
+     *
+     * @return an array of {@link PosLookupRecord}.
+     */
+    public abstract PosLookupRecord[] getPosLookupRecords();
+
+}

io/src/main/java/com/itextpdf/io/font/otf/ContextualPositionTable.java

@@ -0,0 +1,32 @@
+/*
+    This file is part of the iText (R) project.
+    Copyright (c) 1998-2020 iText Group NV
+    Authors: iText Software.
+
+    This program is offered under a commercial and under the AGPL license.
+    For commercial licensing, contact us at https://itextpdf.com/sales.  For AGPL licensing, see below.
+
+    AGPL licensing:
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program 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 Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.itextpdf.io.font.otf;
+
+public abstract class ContextualPositionTable extends ContextualTable<ContextualPositionRule> {
+    private static final long serialVersionUID = -5767338869523894047L;
+
+    protected ContextualPositionTable(OpenTypeFontTableReader openReader, int lookupFlag) {
+        super(openReader, lookupFlag);
+    }
+
+}

io/src/main/java/com/itextpdf/io/font/otf/ContextualRule.java

@@ -0,0 +1,85 @@
+/*
+    This file is part of the iText (R) project.
+    Copyright (c) 1998-2020 iText Group NV
+    Authors: iText Software.
+
+    This program is offered under a commercial and under the AGPL license.
+    For commercial licensing, contact us at https://itextpdf.com/sales.  For AGPL licensing, see below.
+
+    AGPL licensing:
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program 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 Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.itextpdf.io.font.otf;
+
+import java.io.Serializable;
+
+public abstract class ContextualRule implements Serializable {
+    private static final long serialVersionUID = -9013175115747848532L;
+
+    /**
+     * Gets the length of the context glyph sequence defined by this rule
+     * @return length of the context
+     */
+    public abstract int getContextLength();
+
+    /**
+     * Checks if glyph line element matches element from input sequence of the rule.
+     * <br><br>
+     * NOTE: rules do not contain the first element of the input sequence, the first element is defined by rule
+     * position in substitution table. Therefore atIdx shall not be 0.
+     *
+     * @param glyphId glyph code id
+     * @param atIdx   index in the rule sequence. Shall be: 0 &lt; atIdx &lt; {@link ContextualSubstRule#getContextLength}
+     * @return {@code true} if glyph matches element
+     */
+    public abstract boolean isGlyphMatchesInput(int glyphId, int atIdx);
+
+    /**
+     * Gets the length of the lookahead context glyph sequence defined by this rule
+     * @return length of the lookahead context
+     */
+    public int getLookaheadContextLength() {
+        return 0;
+    }
+
+    /**
+     * Gets the length of the backtrack context glyph sequence defined by this rule
+     * @return length of the backtrack context
+     */
+    public int getBacktrackContextLength() {
+        return 0;
+    }
+
+    /**
+     * Checks if glyph line element matches element from lookahead sequence of the rule.
+     *
+     * @param glyphId glyph code id
+     * @param atIdx   index in rule sequence. Shall be: 0 &lt;= atIdx &lt; {@link ContextualSubstRule#getLookaheadContextLength()}
+     * @return {@code true} if glyph matches element from lookahead sequence
+     */
+    public boolean isGlyphMatchesLookahead(int glyphId, int atIdx) {
+        return false;
+    }
+
+    /**
+     * Checks if glyph line element matches element from backtrack sequence of the rule.
+     *
+     * @param glyphId glyph code id
+     * @param atIdx   index in rule sequence. Shall be: 0 &lt;= atIdx &lt; {@link ContextualSubstRule#getBacktrackContextLength()}
+     * @return {@code true} if glyph matches element from backtrack sequence
+     */
+    public boolean isGlyphMatchesBacktrack(int glyphId, int atIdx) {
+        return false;
+    }
+}

io/src/main/java/com/itextpdf/io/font/otf/ContextualSubTable.java

@@ -43,83 +43,23 @@ This file is part of the iText (R) project.
  */
 package com.itextpdf.io.font.otf;
 
-import java.io.Serializable;
-import java.util.List;
-
-public abstract class ContextualSubTable implements Serializable {
+public abstract class ContextualSubTable extends ContextualTable<ContextualSubstRule> {
 
     private static final long serialVersionUID = 1802216575331243298L;
-    protected OpenTypeFontTableReader openReader;
-    protected int lookupFlag;
 
     protected ContextualSubTable(OpenTypeFontTableReader openReader, int lookupFlag) {
-        this.openReader = openReader;
-        this.lookupFlag = lookupFlag;
+        super(openReader, lookupFlag);
     }
 
-    /**
-     * Gets a most preferable context rule that matches the line at current position. If no matching context rule is found,
-     * it returns null.
-     * <br><br>
-     * NOTE: if matching context rule is found, the <code>GlyphLine.start</code> and <code>GlyphLine.end</code> will be
-     * changed in such way, that they will point at start and end of the matching context glyph sequence inside the glyph line.
-     * @param line a line, which is to be checked if it matches some context.
-     * @return matching context rule or null, if none was found.
-     */
+    @Override
+    // TODO DEVSIX-3814 Remove this dummy override. It's left only for binary backwards compatibility
     public ContextualSubstRule getMatchingContextRule(GlyphLine line) {
-        if (line.idx >= line.end)
-            return null;
-
-        Glyph g = line.get(line.idx);
-        List<ContextualSubstRule> rules = getSetOfRulesForStartGlyph(g.getCode());
-        for (ContextualSubstRule rule : rules) {
-            int lastGlyphIndex = checkIfContextMatch(line, rule);
-            if (lastGlyphIndex != -1) {
-                line.start = line.idx;
-                line.end = lastGlyphIndex + 1;
-                return rule;
-            }
-        }
-
-        return null;
+        return super.getMatchingContextRule(line);
     }
 
-    /**
-     * Gets a set of rules, which start with given glyph id.
-     *
-     * @param startId id of the first glyph in the sequence
-     * @return a list of {@link ContextualSubstRule} instances. The list will be empty if there are no rules
-     *     that start with a given glyph id
-     */
-    protected abstract List<ContextualSubstRule> getSetOfRulesForStartGlyph(int startId);
-
-    /**
-     * Checks if given glyph line matches given rule.
-     *
-     * @param line glyph line to be checked
-     * @param rule rule to be compared with a given glyph line
-     * @return either index which corresponds to the last glyph of the matching context inside the glyph line
-     *     if context matches, or -1 if context doesn't match
-     */
+    @Override
+    // TODO DEVSIX-3814 Remove this dummy override. It's left only for binary backwards compatibility
     protected int checkIfContextMatch(GlyphLine line, ContextualSubstRule rule) {
-        int j;
-        OpenTableLookup.GlyphIndexer gidx = new OpenTableLookup.GlyphIndexer();
-        gidx.line = line;
-        gidx.idx = line.idx;
-
-        //Note, that starting index shall be 1
-        for (j = 1; j < rule.getContextLength(); ++j) {
-            gidx.nextGlyph(openReader, lookupFlag);
-            if (gidx.glyph == null || !rule.isGlyphMatchesInput(gidx.glyph.getCode(), j)) {
-                break;
-            }
-        }
-
-        boolean isMatch = j == rule.getContextLength();
-        if (isMatch) {
-            return gidx.idx;
-        } else {
-            return -1;
-        }
+        return super.checkIfContextMatch(line, rule);
     }
 }

io/src/main/java/com/itextpdf/io/font/otf/ContextualSubstRule.java

@@ -43,67 +43,15 @@ This file is part of the iText (R) project.
  */
 package com.itextpdf.io.font.otf;
 
-import java.io.Serializable;
-
-public abstract class ContextualSubstRule implements Serializable {
+public abstract class ContextualSubstRule extends ContextualRule {
     private static final long serialVersionUID = -8640866820690910047L;
 
     /**
-     * @return length of the context glyph sequence defined by this rule
-     */
-    public abstract int getContextLength();
-
-    /**
-     * @return an array of <code>SubstLookupRecord</code>. Each record specifies a position in the context glyph
-     * sequence and a LookupListIndex to the substitution lookup that is applied at that position
-     */
-    public abstract SubstLookupRecord[] getSubstLookupRecords();
-
-    /**
-     * Checks if glyph line element matches element from input sequence of the rule.
-     * <br><br>
-     * NOTE: rules do not contain the first element of the input sequence, the first element is defined by rule
-     * position in substitution table. Therefore atIdx shall not be 0.
-     *
-     * @param glyphId glyph code id
-     * @param atIdx   index in the rule sequence. Shall be: 0 &lt; atIdx &lt; {@link ContextualSubstRule#getContextLength}
-     * @return {@code true} if glyph matches element
-     */
-    public abstract boolean isGlyphMatchesInput(int glyphId, int atIdx);
-
-    /**
-     * @return length of the lookahead context glyph sequence defined by this rule
-     */
-    public int getLookaheadContextLength() {
-        return 0;
-    }
-
-    /**
-     * @return length of the backtrack context glyph sequence defined by this rule
-     */
-    public int getBacktrackContextLength() {
-        return 0;
-    }
-
-    /**
-     * Checks if glyph line element matches element from lookahead sequence of the rule.
+     * Retrieves the substitution lookup records. Each record specifies a position in the context glyph
+     * sequence and a LookupListIndex to the substitution lookup that is applied at that position.
      *
-     * @param glyphId glyph code id
-     * @param atIdx   index in rule sequence. Shall be: 0 &lt;= atIdx &lt; {@link ContextualSubstRule#getLookaheadContextLength()}
-     * @return {@code true} if glyph matches element from lookahead sequence
+     * @return an array of {@link SubstLookupRecord}.
      */
-    public boolean isGlyphMatchesLookahead(int glyphId, int atIdx) {
-        return false;
-    }
+    public abstract SubstLookupRecord[] getSubstLookupRecords();
 
-    /**
-     * Checks if glyph line element matches element from backtrack sequence of the rule.
-     *
-     * @param glyphId glyph code id
-     * @param atIdx   index in rule sequence. Shall be: 0 &lt;= atIdx &lt; {@link ContextualSubstRule#getBacktrackContextLength()}
-     * @return {@code true} if glyph matches element from backtrack sequence
-     */
-    public boolean isGlyphMatchesBacktrack(int glyphId, int atIdx) {
-        return false;
-    }
 }