Explicitly set built-in fonts on freetext annotations flattening

This logic is closer to how Acrobat displays freetext annotations,
and also fixes NPE while processing such annotations with
PdfContentStreamProcessor after flattening.

DEV-1896

Author: IdamkinI

itext/src/main/java/com/itextpdf/text/pdf/BaseFont.java

@@ -1496,6 +1496,21 @@ public static ArrayList<Object[]> getDocumentFonts(PdfReader reader, int page) {
         return fonts;
     }
 
+    static PdfDictionary createBuiltInFontDictionary(String name) {
+        return createBuiltInFontDictionary(BuiltinFonts14.get(name));
+    }
+
+    private static PdfDictionary createBuiltInFontDictionary(PdfName name) {
+        if (name == null) {
+            return null;
+        }
+        PdfDictionary dictionary = new PdfDictionary();
+        dictionary.put(PdfName.TYPE, PdfName.FONT);
+        dictionary.put(PdfName.BASEFONT, name);
+        dictionary.put(PdfName.SUBTYPE, PdfName.TYPE1);
+        return dictionary;
+    }
+
     /**
      * Gets the smallest box enclosing the character contours. It will return
      * <CODE>null</CODE> if the font has not the information or the character has no

itext/src/main/java/com/itextpdf/text/pdf/PdfStamperImp.java

@@ -52,6 +52,8 @@
 import com.itextpdf.text.Version;
 import com.itextpdf.text.error_messages.MessageLocalization;
 import com.itextpdf.text.exceptions.BadPasswordException;
+import com.itextpdf.text.io.RandomAccessSource;
+import com.itextpdf.text.io.RandomAccessSourceFactory;
 import com.itextpdf.text.log.Counter;
 import com.itextpdf.text.log.CounterFactory;
 import com.itextpdf.text.log.Logger;
@@ -80,6 +82,7 @@
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.RandomAccess;
 
 class PdfStamperImp extends PdfWriter {
     HashMap<PdfReader, IntHashtable> readers2intrefs = new HashMap<PdfReader, IntHashtable>();
@@ -125,6 +128,9 @@ protected Counter getCounter() {
      * then original layers are never read - they are simply copied to the new document with whole original catalog. */
     private boolean originalLayersAreRead = false;
 
+    //Hash map of standard fonts used in flattening of annotations to prevent fonts duplication
+    private HashMap<String, PdfIndirectReference> builtInAnnotationFonts = new HashMap<String, PdfIndirectReference>();
+
     private double[] DEFAULT_MATRIX = {1, 0, 0, 1, 0, 0};
 
     /**
@@ -1290,9 +1296,40 @@ private void flattenAnnotations(boolean flattenFreeTextAnnotations) {
                                     final PdfString freeTextContent = annDic.getAsString(PdfName.CONTENTS);
                                     final String defaultAppearanceString = defaultAppearancePdfString.toString();
 
-                                    app = new PdfAppearance(this);
+                                    //It is not stated in spec, but acrobat seems to support standard font names in DA
+                                    //So we need to check if the font is built-in and specify it explicitly.
+                                    PdfIndirectReference fontReference = null;
+                                    PdfName pdfFontName = null;
+                                    try {
+                                        RandomAccessSource source = new RandomAccessSourceFactory().createSource(defaultAppearancePdfString.getBytes());
+                                        PdfContentParser ps = new PdfContentParser(new PRTokeniser(new RandomAccessFileOrArray(source)));
+                                        ArrayList<PdfObject> operands = new ArrayList<PdfObject>();
+                                        while (ps.parse(operands).size() > 0) {
+                                            PdfLiteral operator = (PdfLiteral)operands.get(operands.size()-1);
+                                            if (operator.toString().equals("Tf")) {
+                                                pdfFontName = (PdfName) operands.get(0);
+                                                String fontName = pdfFontName.toString().substring(1);
+                                                fontReference = builtInAnnotationFonts.get(fontName);
+                                                if (fontReference == null) {
+                                                    PdfDictionary dic = BaseFont.createBuiltInFontDictionary(fontName);
+                                                    if (dic != null) {
+                                                        fontReference = addToBody(dic).getIndirectReference();
+                                                        builtInAnnotationFonts.put(fontName, fontReference);
+                                                    }
+                                                }
+                                            }
+                                        }
+                                    } catch (Exception any) {
+                                        logger.warn(MessageLocalization.getComposedMessage("error.resolving.freetext.font"));
+                                        break;
+                                    }
 
+                                    app = new PdfAppearance(this);
+                                    // it is unclear from spec were referenced from DA font should be (since annotations doesn't have DR), so in case it not built-in
                                     // quickly and naively flattening the freetext annotation
+                                    if (fontReference != null) {
+                                        app.getPageResources().addFont(pdfFontName, fontReference);
+                                    }
                                     app.saveState();
                                     app.beginText();
                                     app.setLiteral(defaultAppearanceString);

itext/src/main/resources/com/itextpdf/text/l10n/error/en.lng

@@ -168,6 +168,7 @@ error.in.base64.code.reading.stream=Error in Base64 code reading stream.
 error.parsing.cmap.beginbfchar.expected.cosstring.or.cosname.and.not.1=Error parsing CMap beginbfchar, expected {COSString or COSName} and not {1}
 error.reading.objstm=Error reading ObjStm
 error.reading.string=Error reading string
+error.resolving.freetext.font=Cannot resolve annotation's font. It won't be flattened
 error.with.jp.marker=Error with JP Marker
 every.annotation.shall.have.at.least.one.appearance.dictionary=Every annotation shall have at least one appearance dictionary
 exactly.one.colour.space.specification.shall.have.the.value.0x01.in.the.approx.field=Exactly one colour space specification shall have the value 0x01 in the APPROX field.

itext/src/main/resources/com/itextpdf/text/l10n/error/nl.lng

@@ -168,6 +168,7 @@ error.in.base64.code.reading.stream=Fout in de Base64 code reading stream.
 error.parsing.cmap.beginbfchar.expected.cosstring.or.cosname.and.not.1=Fout bij het parsen van CMap beginbfchar, {COSString or COSName} verwacht in plaats van {1}
 error.reading.objstm=Fout tijdens het lezen van ObjStm
 error.reading.string=Fout bij het lezen van een string
+error.resolving.freetext.font=Kan het lettertype van annotatie niet oplossen. Het wordt niet afgedrukt
 error.with.jp.marker=Foute JP Marker
 every.annotation.shall.have.at.least.one.appearance.dictionary=Elke annotation moet ten minste 1 appearance dictionary hebben
 exactly.one.colour.space.specification.shall.have.the.value.0x01.in.the.approx.field=Exact 1 colour space specificatie moet de waarde 0x01 in het APPROX veld hebben.

itext/src/test/java/com/itextpdf/text/pdf/FreeTextFlatteningTest.java

@@ -45,46 +45,80 @@ This file is part of the iText (R) project.
 import com.itextpdf.testutils.CompareTool;
 import com.itextpdf.text.DocumentException;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 
+import com.itextpdf.text.pdf.parser.ContentByteUtils;
+import com.itextpdf.text.pdf.parser.ImageRenderInfo;
+import com.itextpdf.text.pdf.parser.PdfContentStreamProcessor;
+import com.itextpdf.text.pdf.parser.RenderListener;
+import com.itextpdf.text.pdf.parser.TextRenderInfo;
 import org.junit.Assert;
+import org.junit.BeforeClass;
 import org.junit.Test;
 
 public class FreeTextFlatteningTest {
 
-    private final String FOLDER = "./src/test/resources/com/itextpdf/text/pdf/FreeTextFlatteningTest/";
+    private final static String FOLDER = "./src/test/resources/com/itextpdf/text/pdf/FreeTextFlatteningTest/";
+    private final static String TARGET = "./target/com/itextpdf/test/pdf/FreeTextFlattening/";
 
+    @BeforeClass
+    public static void setUp() {
+        new File(TARGET).mkdirs();
+    }
 
     @Test
     public void flattenCorrectlyTest() throws IOException, DocumentException, InterruptedException {
-        String target = "./target/com/itextpdf/test/pdf/FreeTextFlattening/";
-        new File(target).mkdirs();
-        String outputFile = target + "freetext-flattened.pdf";
+        String outputFile = TARGET + "freetext-flattened.pdf";
 
-        flattenFreeText(new FileInputStream(FOLDER + "freetext.pdf"), new FileOutputStream(outputFile));
-        checkFlattenedPdf(new FileInputStream(outputFile), 0);
+        flattenFreeText(FOLDER + "freetext.pdf", outputFile);
+        checkAnnotationSize(outputFile, 0);
 
-        String errorMessage = new CompareTool().compare(outputFile, FOLDER + "flattened.pdf", target, "diff");
+        String errorMessage = new CompareTool().compareByContent(outputFile, FOLDER + "flattened.pdf", TARGET, "diff");
         if ( errorMessage != null ) {
             Assert.fail(errorMessage);
         }
     }
 
+    @Test
+    public void checkPageContentTest() throws IOException, DocumentException, InterruptedException {
+        checkPageContent(FOLDER + "flattened.pdf");
+    }
+
     @Test
     public void flattenWithoutDA() throws IOException, DocumentException {
-        ByteArrayOutputStream baos = new ByteArrayOutputStream();
-        flattenFreeText(new FileInputStream(FOLDER + "freetext-no-da.pdf"), baos);
-        checkFlattenedPdf(new ByteArrayInputStream(baos.toByteArray()), 1);
+        String outputFile = TARGET + "freetext-flattened-no-da.pdf";
+
+        flattenFreeText(FOLDER + "freetext-no-da.pdf", outputFile);
+        checkAnnotationSize(outputFile, 1);
+    }
+
+    @Test
+    public void flattenAndCheckCourier() throws IOException, DocumentException, InterruptedException {
+        String inputFile = FOLDER + "freetext-courier.pdf";
+        String outputFile = TARGET + "freetext-courier-flattened.pdf";
+
+        flattenFreeText(inputFile, outputFile);
+        checkPageContent(outputFile);
+    }
+
+    private void checkAnnotationSize(String path, int expectedAnnotationsSize) throws IOException, DocumentException {
+        FileInputStream fin = null;
+        try {
+            fin = new FileInputStream(path);
+            checkAnnotationSize(fin, expectedAnnotationsSize);
+        } finally {
+            if (fin != null) {
+                fin.close();
+            }
+        }
     }
 
-    private void checkFlattenedPdf(InputStream inputStream, int expectedAnnotationsSize) throws IOException, DocumentException {
+    private void checkAnnotationSize(InputStream inputStream, int expectedAnnotationsSize) throws IOException, DocumentException {
         PdfReader reader = new PdfReader(inputStream);
         PdfDictionary pageDictionary = reader.getPageN(1);
         if ( pageDictionary.contains(PdfName.ANNOTS )) {
@@ -93,6 +127,23 @@ private void checkFlattenedPdf(InputStream inputStream, int expectedAnnotationsS
         }
     }
 
+    private void flattenFreeText(String inputPath, String outputPath) throws IOException, DocumentException {
+        FileInputStream fin = null;
+        FileOutputStream fout = null;
+        try {
+            fin = new FileInputStream(inputPath);
+            fout = new FileOutputStream(outputPath);
+            flattenFreeText(fin, fout);
+        } finally {
+            if (fin != null) {
+                fin.close();
+            }
+            if (fout != null) {
+                fout.close();
+            }
+        }
+    }
+
     private void flattenFreeText(final InputStream inputStream, OutputStream outputStream) throws IOException, DocumentException {
         PdfReader reader = new PdfReader(inputStream);
         PdfStamper stamper = new PdfStamper(reader, outputStream);
@@ -103,4 +154,31 @@ private void flattenFreeText(final InputStream inputStream, OutputStream outputS
 
         stamper.close();
     }
+
+    private void checkPageContent(String path) throws IOException, DocumentException {
+        PdfReader pdfReader = new PdfReader(path);
+        try {
+            PdfDictionary pageDic = pdfReader.getPageN(1);
+
+            RenderListener dummy = new RenderListener() {
+                public void beginTextBlock() {
+                }
+
+                public void renderText(TextRenderInfo renderInfo) {
+                }
+
+                public void endTextBlock() {
+                }
+
+                public void renderImage(ImageRenderInfo renderInfo) {
+                }
+            };
+            PdfContentStreamProcessor processor = new PdfContentStreamProcessor(dummy);
+
+            PdfDictionary resourcesDic = pageDic.getAsDict(PdfName.RESOURCES);
+            processor.processContent(ContentByteUtils.getContentBytesForPage(pdfReader, 1), resourcesDic);
+        } finally {
+            pdfReader.close();
+        }
+    }
 }