OpenType: Fix skipping glyphs for mark attachment type-specific lookup flags

In case mark attachment class is not defined for a glyph whereas the
mark attachment type is defined in the lookup flag, such glyph still
needs to be skipped because only the marks matching the desired mark
attachment type should be considered

DEVSIX-4587

Author: Snipx

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

@@ -49,10 +49,11 @@ This file is part of the iText (R) project.
 
 public class OpenTypeGdefTableReader implements Serializable{
 
+    static final int FLAG_IGNORE_BASE = 2;
+    static final int FLAG_IGNORE_LIGATURE = 4;
+    static final int FLAG_IGNORE_MARK = 8;
+
     private static final long serialVersionUID = 1564505797329158035L;
-    private final int FLAG_IGNORE_BASE = 2;
-    private final int FLAG_IGNORE_LIGATURE = 4;
-    private final int FLAG_IGNORE_MARK = 8;
 
     private final int tableLocation;
     private final RandomAccessFileOrArray rf;
@@ -97,8 +98,16 @@ public boolean isSkip(int glyph, int flag) {
                 return true;
             }
         }
-        if (markAttachmentClass != null && markAttachmentClass.getOtfClass(glyph) > 0 && (flag >> 8) > 0) {
-            return markAttachmentClass.getOtfClass(glyph) != (flag >> 8);
+        int markAttachmentType = (flag >> 8);
+        // If MarkAttachmentType is non-zero, then mark attachment classes must be defined in the
+        // Mark Attachment Class Definition Table in the GDEF table. When processing glyph sequences,
+        // a lookup must ignore any mark glyphs that are not in the specified mark attachment class;
+        // only marks of the specified type are processed.
+        if (markAttachmentType != 0 && glyphClass != null) {
+            int currentGlyphClass = glyphClass.getOtfClass(glyph);
+            // Will be 0 in case the class is not defined for this particular glyph
+            int glyphMarkAttachmentClass = markAttachmentClass != null ? markAttachmentClass.getOtfClass(glyph) : 0;
+            return currentGlyphClass == OtfClass.GLYPH_MARK && glyphMarkAttachmentClass != markAttachmentType;
         }
         return false;
     }

io/src/test/java/com/itextpdf/io/font/otf/OpenTypeGdefTableReaderTest.java

@@ -0,0 +1,47 @@
+package com.itextpdf.io.font.otf;
+
+import com.itextpdf.io.font.FontProgramFactory;
+import com.itextpdf.io.font.TrueTypeFont;
+import com.itextpdf.test.ExtendedITextTest;
+import com.itextpdf.test.annotations.type.IntegrationTest;
+
+import java.io.IOException;
+import org.junit.Assert;
+import org.junit.Test;
+import org.junit.experimental.categories.Category;
+
+@Category(IntegrationTest.class)
+public class OpenTypeGdefTableReaderTest extends ExtendedITextTest {
+    private static final String RESOURCE_FOLDER = "./src/test/resources/com/itextpdf/io/font/otf/OpenTypeGdefTableReaderTest/";
+
+    @Test
+    public void testLookupFlagWithMarkAttachmentTypeAndMarkGlyphWithoutMarkAttachmentClass() throws IOException {
+        String fontName = "Padauk-Regular.ttf";
+        TrueTypeFont fontProgram = (TrueTypeFont)FontProgramFactory.createFont(RESOURCE_FOLDER + fontName);
+        OpenTypeGdefTableReader gdef = fontProgram.getGdefTable();
+        int glyphCode = 207;
+        Assert.assertEquals(OtfClass.GLYPH_MARK, gdef.getGlyphClassTable().getOtfClass(glyphCode));
+        Assert.assertTrue(gdef.isSkip(glyphCode, (1 << 8) | OpenTypeGdefTableReader.FLAG_IGNORE_BASE));
+    }
+
+    @Test
+    public void testLookupFlagWithMarkAttachmentTypeAndMarkGlyphWithSameMarkAttachmentClass() throws IOException {
+        String fontName = "Padauk-Regular.ttf";
+        TrueTypeFont fontProgram = (TrueTypeFont)FontProgramFactory.createFont(RESOURCE_FOLDER + fontName);
+        OpenTypeGdefTableReader gdef = fontProgram.getGdefTable();
+        int glyphCode = 151;
+        Assert.assertEquals(OtfClass.GLYPH_MARK, gdef.getGlyphClassTable().getOtfClass(glyphCode));
+        Assert.assertFalse(gdef.isSkip(glyphCode, (1 << 8) | OpenTypeGdefTableReader.FLAG_IGNORE_BASE));
+    }
+
+    @Test
+    public void testLookupFlagWithMarkAttachmentTypeAndBaseGlyph() throws IOException {
+        String fontName = "Padauk-Regular.ttf";
+        TrueTypeFont fontProgram = (TrueTypeFont)FontProgramFactory.createFont(RESOURCE_FOLDER + fontName);
+        OpenTypeGdefTableReader gdef = fontProgram.getGdefTable();
+        int glyphCode = 165;
+        Assert.assertEquals(OtfClass.GLYPH_BASE, gdef.getGlyphClassTable().getOtfClass(glyphCode));
+        Assert.assertFalse(gdef.isSkip(glyphCode, (1 << 8)));
+    }
+
+}

io/src/test/resources/com/itextpdf/io/font/otf/OpenTypeGdefTableReaderTest/LICENSE_OFL.txt

@@ -0,0 +1,92 @@
+This Font Software is licensed under the SIL Open Font License,
+Version 1.1.
+
+This license is copied below, and is also available with a FAQ at:
+http://scripts.sil.org/OFL
+
+-----------------------------------------------------------
+SIL OPEN FONT LICENSE Version 1.1 - 26 February 2007
+-----------------------------------------------------------
+
+PREAMBLE
+The goals of the Open Font License (OFL) are to stimulate worldwide
+development of collaborative font projects, to support the font
+creation efforts of academic and linguistic communities, and to
+provide a free and open framework in which fonts may be shared and
+improved in partnership with others.
+
+The OFL allows the licensed fonts to be used, studied, modified and
+redistributed freely as long as they are not sold by themselves. The
+fonts, including any derivative works, can be bundled, embedded,
+redistributed and/or sold with any software provided that any reserved
+names are not used by derivative works. The fonts and derivatives,
+however, cannot be released under any other type of license. The
+requirement for fonts to remain under this license does not apply to
+any document created using the fonts or their derivatives.
+
+DEFINITIONS
+"Font Software" refers to the set of files released by the Copyright
+Holder(s) under this license and clearly marked as such. This may
+include source files, build scripts and documentation.
+
+"Reserved Font Name" refers to any names specified as such after the
+copyright statement(s).
+
+"Original Version" refers to the collection of Font Software
+components as distributed by the Copyright Holder(s).
+
+"Modified Version" refers to any derivative made by adding to,
+deleting, or substituting -- in part or in whole -- any of the
+components of the Original Version, by changing formats or by porting
+the Font Software to a new environment.
+
+"Author" refers to any designer, engineer, programmer, technical
+writer or other person who contributed to the Font Software.
+
+PERMISSION & CONDITIONS
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of the Font Software, to use, study, copy, merge, embed,
+modify, redistribute, and sell modified and unmodified copies of the
+Font Software, subject to the following conditions:
+
+1) Neither the Font Software nor any of its individual components, in
+Original or Modified Versions, may be sold by itself.
+
+2) Original or Modified Versions of the Font Software may be bundled,
+redistributed and/or sold with any software, provided that each copy
+contains the above copyright notice and this license. These can be
+included either as stand-alone text files, human-readable headers or
+in the appropriate machine-readable metadata fields within text or
+binary files as long as those fields can be easily viewed by the user.
+
+3) No Modified Version of the Font Software may use the Reserved Font
+Name(s) unless explicit written permission is granted by the
+corresponding Copyright Holder. This restriction only applies to the
+primary font name as presented to the users.
+
+4) The name(s) of the Copyright Holder(s) or the Author(s) of the Font
+Software shall not be used to promote, endorse or advertise any
+Modified Version, except to acknowledge the contribution(s) of the
+Copyright Holder(s) and the Author(s) or with their explicit written
+permission.
+
+5) The Font Software, modified or unmodified, in part or in whole,
+must be distributed entirely under this license, and must not be
+distributed under any other license. The requirement for fonts to
+remain under this license does not apply to any document created using
+the Font Software.
+
+TERMINATION
+This license becomes null and void if any of the above conditions are
+not met.
+
+DISCLAIMER
+THE FONT SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT
+OF COPYRIGHT, PATENT, TRADEMARK, OR OTHER RIGHT. IN NO EVENT SHALL THE
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+OTHER DEALINGS IN THE FONT SOFTWARE.

io/src/test/resources/com/itextpdf/io/font/otf/OpenTypeGdefTableReaderTest/NOTICE.txt

@@ -0,0 +1,2 @@
+This software uses the following test resources under the following licenses:
+| Padauk-Regular.ttf | OFL-1.1 | LICENSE-OFL.txt |