Fix for loading of TIFF with transparency.

openpdf/src/main/java/com/lowagie/text/pdf/codec/TiffImage.java

@@ -325,11 +325,12 @@ else if (rot == TIFFConstants.ORIENTATION_RIGHTTOP || rot == TIFFConstants.ORIEN
             if (dir.isTagPresent(TIFFConstants.TIFFTAG_PLANARCONFIG)
                 && dir.getFieldAsLong(TIFFConstants.TIFFTAG_PLANARCONFIG) == TIFFConstants.PLANARCONFIG_SEPARATE)
                 throw new IllegalArgumentException(MessageLocalization.getComposedMessage("planar.images.are.not.supported"));
-            if (dir.isTagPresent(TIFFConstants.TIFFTAG_EXTRASAMPLES))
-                throw new IllegalArgumentException(MessageLocalization.getComposedMessage("extra.samples.are.not.supported"));
             int samplePerPixel = 1;
             if (dir.isTagPresent(TIFFConstants.TIFFTAG_SAMPLESPERPIXEL)) // 1,3,4
                 samplePerPixel = (int)dir.getFieldAsLong(TIFFConstants.TIFFTAG_SAMPLESPERPIXEL);
+            if (dir.isTagPresent(TIFFConstants.TIFFTAG_EXTRASAMPLES))
+                if(samplePerPixel != 4) // TIFFTAG_EXTRASAMPLES is supposed to be set when RGB image data has an alpha channel (the 4th channel in this case).
+                    throw new IllegalArgumentException(MessageLocalization.getComposedMessage("extra.samples.are.not.supported"));
             int bitsPerSample = 1;
             if (dir.isTagPresent(TIFFConstants.TIFFTAG_BITSPERSAMPLE))
                 bitsPerSample = (int)dir.getFieldAsLong(TIFFConstants.TIFFTAG_BITSPERSAMPLE);

openpdf/src/test/java/com/lowagie/text/pdf/codec/TiffReadingTest.java

@@ -0,0 +1,42 @@
+package com.lowagie.text.pdf.codec;
+
+import com.lowagie.text.pdf.RandomAccessFileOrArray;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * Tiff2PdfTest
+ *
+ * @author tellef
+ * @date 02.10.2017
+ */
+public class TiffReadingTest {
+
+    @Test
+    public void transparentTiffTest() throws IOException {
+        InputStream inputStream = TiffReadingTest.class.getClassLoader().getResourceAsStream("gradient.tiff");
+        byte[] data;
+
+        try(ByteArrayOutputStream byteOutputStream = new ByteArrayOutputStream()) {
+            int bytesRead;
+            byte[] buffer = new byte[8192];
+
+            while ((bytesRead = inputStream.read(buffer, 0, 8192)) != -1) {
+                byteOutputStream.write(buffer, 0, bytesRead);
+            }
+
+            data = byteOutputStream.toByteArray();
+        }
+
+        RandomAccessFileOrArray ra = new RandomAccessFileOrArray(data);
+        int pages = TiffImage.getNumberOfPages(ra);
+
+        for (int i = 1; i <= pages; i++) {
+            Assert.assertNotNull(TiffImage.getTiffImage(ra, i));
+        }
+    }
+}