Do not add subset prefix for external fonts.

DEVSIX-1621

Author: pavel-alay

kernel/src/main/java/com/itextpdf/kernel/font/PdfFont.java

@@ -531,6 +531,7 @@ protected boolean checkTrueTypeFontDictionary(PdfDictionary fontDic, boolean isE
      *
      * @return the subset prefix
      */
+    @Deprecated
     protected static String createSubsetPrefix() {
         StringBuilder s = new StringBuilder("");
         for (int k = 0; k < 6; ++k) {
@@ -539,6 +540,22 @@ protected static String createSubsetPrefix() {
         return s + "+";
     }
 
+    /**
+     * Adds a unique subset prefix to be added to the font name when the font is embedded and subset.
+     *
+     * @return the font name with subset prefix if isSubset and isEmbedded are true.s
+     */
+    protected static String updateSubsetPrefix(String fontName, boolean isSubset, boolean isEmbedded) {
+        if (isSubset && isEmbedded) {
+            StringBuilder s = new StringBuilder(fontName.length() + 7);
+            for (int k = 0; k < 6; ++k) {
+                s.append((char) (Math.random() * 26 + 'A'));
+            }
+            return s.append('+').append(fontName).toString();
+        }
+        return fontName;
+    }
+
     /**
      * Create {@code PdfStream} based on {@code fontStreamBytes}.
      *

kernel/src/main/java/com/itextpdf/kernel/font/PdfTrueTypeFont.java

@@ -139,9 +139,7 @@ public void flush() {
                 fontName = fontProgram.getFontNames().getFontName();
             } else {
                 subtype = PdfName.TrueType;
-                fontName = subset
-                        ? createSubsetPrefix() + fontProgram.getFontNames().getFontName()
-                        : fontProgram.getFontNames().getFontName();
+                fontName = updateSubsetPrefix(fontProgram.getFontNames().getFontName(), subset, embedded);
             }
             flushFontData(fontName, subtype);
         }

kernel/src/main/java/com/itextpdf/kernel/font/PdfType0Font.java

@@ -831,10 +831,7 @@ private void flushFontData() {
             int[][] metrics = longTag.values().toArray(new int[0][]);
             Arrays.sort(metrics, new MetricComparator());
             PdfStream fontStream;
-            String fontName = ttf.getFontNames().getFontName();
-            if (subset) {
-                fontName = createSubsetPrefix() + fontName;
-            }
+            String fontName = updateSubsetPrefix(ttf.getFontNames().getFontName(), subset, embedded);
             PdfDictionary fontDescriptor = getFontDescriptor(fontName);
             if (ttf.isCff()) {
                 byte[] cffBytes = ttf.getFontStreamBytes();

kernel/src/test/java/com/itextpdf/kernel/pdf/PdfFontTest.java

@@ -584,6 +584,55 @@ public void createDocumentWithTrueTypeFont1() throws IOException, InterruptedExc
         Assert.assertNull(new CompareTool().compareByContent(filename, cmpFilename, destinationFolder, "diff_"));
     }
 
+    @Test
+    public void createDocumentWithTrueTypeFont1NotEmbedded() throws IOException, InterruptedException {
+        String filename = destinationFolder + "createDocumentWithTrueTypeFont1NotEmbedded.pdf";
+        String cmpFilename = sourceFolder + "cmp_createDocumentWithTrueTypeFont1NotEmbedded.pdf";
+        String title = "Empty iText 7 Document";
+        PdfWriter writer = new PdfWriter(filename);
+        writer.setCompressionLevel(CompressionConstants.NO_COMPRESSION);
+        PdfDocument pdfDoc = new PdfDocument(writer);
+        pdfDoc.getDocumentInfo().setAuthor(author).
+                setCreator(creator).
+                setTitle(title);
+        String font = fontsFolder + "abserif4_5.ttf";
+        PdfFont pdfTrueTypeFont = PdfFontFactory.createFont(font, false);
+        Assert.assertTrue("PdfTrueTypeFont expected", pdfTrueTypeFont instanceof PdfTrueTypeFont);
+        pdfTrueTypeFont.setSubset(true);
+        PdfPage page = pdfDoc.addNewPage();
+        new PdfCanvas(page)
+                .saveState()
+                .beginText()
+                .moveText(36, 700)
+                .setFontAndSize(pdfTrueTypeFont, 72)
+                .showText("Hello world")
+                .endText()
+                .restoreState()
+                .rectangle(100, 500, 100, 100).fill()
+                .release();
+        page.flush();
+
+        byte[] ttf = StreamUtil.inputStreamToArray(new FileInputStream(font));
+        pdfTrueTypeFont = PdfFontFactory.createFont(ttf, false);
+        Assert.assertTrue("PdfTrueTypeFont expected", pdfTrueTypeFont instanceof PdfTrueTypeFont);
+        pdfTrueTypeFont.setSubset(true);
+        page = pdfDoc.addNewPage();
+        new PdfCanvas(page)
+                .saveState()
+                .beginText()
+                .moveText(36, 700)
+                .setFontAndSize(pdfTrueTypeFont, 72)
+                .showText("Hello world")
+                .endText()
+                .restoreState()
+                .rectangle(100, 500, 100, 100).fill()
+                .release();
+
+        pdfDoc.close();
+
+        Assert.assertNull(new CompareTool().compareByContent(filename, cmpFilename, destinationFolder, "diff_"));
+    }
+
     @Test
     public void createDocumentWithTrueTypeOtfFont() throws IOException, InterruptedException {
         String filename = destinationFolder + "DocumentWithTrueTypeOtfFont.pdf";
@@ -1310,7 +1359,59 @@ public void testWriteTTC() throws IOException, InterruptedException {
         pdfDoc.close();
 
         Assert.assertNull(new CompareTool().compareByContent(filename, cmpFilename, destinationFolder, "diff_"));
+    }
 
+    @Test
+    public void testWriteTTCNotEmbedded() throws IOException, InterruptedException {
+        String filename = destinationFolder + "testWriteTTCNotEmbedded.pdf";
+        String cmpFilename = sourceFolder + "cmp_testWriteTTCNotEmbedded.pdf";
+        String title = "Empty iText 7 Document";
+
+        PdfWriter writer = new PdfWriter(filename);
+        writer.setCompressionLevel(CompressionConstants.NO_COMPRESSION);
+        PdfDocument pdfDoc = new PdfDocument(writer);
+        pdfDoc.getDocumentInfo().setAuthor(author).
+                setCreator(creator).
+                setTitle(title);
+
+        String font = fontsFolder + "uming.ttc";
+
+        PdfFont pdfTrueTypeFont = PdfFontFactory.createTtcFont(font, 0, PdfEncodings.WINANSI, false, false);
+
+        pdfTrueTypeFont.setSubset(true);
+        PdfPage page = pdfDoc.addNewPage();
+        PdfCanvas canvas = new PdfCanvas(page);
+        canvas
+                .saveState()
+                .beginText()
+                .moveText(36, 700)
+                .setFontAndSize(pdfTrueTypeFont, 72)
+                .showText("Hello world")
+                .endText()
+                .restoreState();
+        canvas.rectangle(100, 500, 100, 100).fill();
+        canvas.release();
+        page.flush();
+
+        byte[] ttc = StreamUtil.inputStreamToArray(new FileInputStream(font));
+        pdfTrueTypeFont = PdfFontFactory.createTtcFont(ttc, 1, PdfEncodings.WINANSI, false, false);
+        pdfTrueTypeFont.setSubset(true);
+        page = pdfDoc.addNewPage();
+        canvas = new PdfCanvas(page);
+        canvas
+                .saveState()
+                .beginText()
+                .moveText(36, 700)
+                .setFontAndSize(pdfTrueTypeFont, 72)
+                .showText("Hello world")
+                .endText()
+                .restoreState();
+        canvas.rectangle(100, 500, 100, 100).fill();
+        canvas.release();
+
+        pdfDoc.close();
+
+        Assert.assertNull(new CompareTool().compareByContent(filename, cmpFilename, destinationFolder, "diff_"));
     }
 
     @Test