Fix for TIFFs with multiple image elements (#89)

examples/kim-kotlin-jvm-sample/src/main/kotlin/Main.kt

@@ -1,5 +1,4 @@
 import com.ashampoo.kim.Kim
-import com.ashampoo.kim.common.ByteOrder
 import com.ashampoo.kim.common.writeBytes
 import com.ashampoo.kim.format.jpeg.JpegRewriter
 import com.ashampoo.kim.format.tiff.TiffContents
@@ -156,9 +155,7 @@ fun setGeoTiffToTiff() {
 
     OutputStreamByteWriter(outputFile.outputStream()).use { outputStreamByteWriter ->
 
-        val tiffWriter = TiffWriterLossy(
-            ByteOrder.LITTLE_ENDIAN
-        )
+        val tiffWriter = TiffWriterLossy(outputSet.byteOrder)
 
         tiffWriter.write(
             byteWriter = outputStreamByteWriter,
@@ -202,9 +199,7 @@ fun setGeoTiffToTiffUsingKotlinx() {
 
     val byteArrayByteWriter = ByteArrayByteWriter()
 
-    val tiffWriter = TiffWriterLossy(
-        ByteOrder.LITTLE_ENDIAN
-    )
+    val tiffWriter = TiffWriterLossy(outputSet.byteOrder)
 
     tiffWriter.write(
         byteWriter = byteArrayByteWriter,
@@ -261,9 +256,7 @@ fun setGeoTiffToTiffUsingKotlinxAndTiffReader() {
 
     val byteArrayByteWriter = ByteArrayByteWriter()
 
-    val tiffWriter = TiffWriterLossy(
-        ByteOrder.LITTLE_ENDIAN
-    )
+    val tiffWriter = TiffWriterLossy(outputSet.byteOrder)
 
     tiffWriter.write(
         byteWriter = byteArrayByteWriter,

src/commonMain/kotlin/com/ashampoo/kim/format/tiff/TiffContents.kt

@@ -37,7 +37,7 @@ data class TiffContents(
 
     fun getExifThumbnailBytes(): ByteArray? =
         directories.asSequence()
-            .mapNotNull { it.thumbnailImageDataElement?.bytes }
+            .mapNotNull { it.thumbnailBytes }
             .firstOrNull()
 
     fun createOutputSet(): TiffOutputSet {

src/commonMain/kotlin/com/ashampoo/kim/format/tiff/TiffDirectory.kt

@@ -53,8 +53,8 @@ class TiffDirectory(
         TiffConstants.TIFF_ENTRY_LENGTH + TiffConstants.TIFF_DIRECTORY_FOOTER_LENGTH
 ) {
 
-    var thumbnailImageDataElement: JpegImageDataElement? = null
-    var tiffImageDataElement: TiffImageDataElement? = null
+    var thumbnailBytes: ByteArray? = null
+    var tiffImageBytes: ByteArray? = null
 
     fun getDirectoryEntries(): List<TiffField> = entries
 
@@ -124,7 +124,7 @@ class TiffDirectory(
         return field.valueBytes.toInts(field.byteOrder)
     }
 
-    fun getJpegImageDataElement(): ImageDataElement {
+    fun getJpegImageDataElement(): ImageDataElement? {
 
         val jpegInterchangeFormat = findField(TiffTag.TIFF_TAG_JPEG_INTERCHANGE_FORMAT)
         val jpegInterchangeFormatLength = findField(TiffTag.TIFF_TAG_JPEG_INTERCHANGE_FORMAT_LENGTH)
@@ -137,23 +137,35 @@ class TiffDirectory(
             return ImageDataElement(offset, byteCount)
         }
 
-        throw ImageReadException("Couldn't find image data.")
+        return null
     }
 
-    fun getStripImageDataElement(): ImageDataElement {
+    /**
+     * Returns a list as tiff image bytes can be splitted upon the whole file.
+     * ImageIO creates small splits while GIMP creates a single big chunk.
+     */
+    fun getStripImageDataElements(): List<ImageDataElement>? {
 
         val offsetField = findField(TiffTag.TIFF_TAG_STRIP_OFFSETS)
         val lengthField = findField(TiffTag.TIFF_TAG_STRIP_BYTE_COUNTS)
 
         if (offsetField != null && lengthField != null) {
 
-            val offset = offsetField.toInt()
-            val length = lengthField.toInt()
+            val offsets = offsetField.toIntArray()
+            val lengths = lengthField.toIntArray()
+
+            if (offsets.size != lengths.size)
+                throw ImageReadException("Offsets & Lengths mismatch: ${offsets.size} != ${lengths.size}")
+
+            val imageDataElements = mutableListOf<ImageDataElement>()
 
-            return ImageDataElement(offset, length)
+            for (index in offsets.indices)
+                imageDataElements.add(ImageDataElement(offsets[index], lengths[index]))
+
+            return imageDataElements
         }
 
-        throw ImageReadException("Couldn't find image data.")
+        return null
     }
 
     fun createOutputDirectory(byteOrder: ByteOrder): TiffOutputDirectory {
@@ -229,9 +241,8 @@ class TiffDirectory(
                     )
             }
 
-            outputDirectory.setThumbnailImageDataElement(thumbnailImageDataElement)
-
-            outputDirectory.setTiffImageDataElement(tiffImageDataElement)
+            outputDirectory.setThumbnailBytes(thumbnailBytes)
+            outputDirectory.setTiffImageBytes(tiffImageBytes)
 
             return outputDirectory
 

src/commonMain/kotlin/com/ashampoo/kim/format/tiff/TiffReader.kt

@@ -37,6 +37,7 @@ import com.ashampoo.kim.format.tiff.taginfo.TagInfoLongs
 import com.ashampoo.kim.input.ByteArrayByteReader
 import com.ashampoo.kim.input.ByteReader
 import com.ashampoo.kim.input.RandomAccessByteReader
+import com.ashampoo.kim.output.ByteArrayByteWriter
 
 object TiffReader {
 
@@ -183,10 +184,10 @@ object TiffReader {
         )
 
         if (directory.hasJpegImageData())
-            directory.thumbnailImageDataElement = getJpegImageDataElement(byteReader, directory)
+            directory.thumbnailBytes = readThumbnailBytes(byteReader, directory)
 
         if (directory.hasStripImageData())
-            directory.tiffImageDataElement = getStripImageDataElement(byteReader, directory)
+            directory.tiffImageBytes = readTiffImageBytes(byteReader, directory)
 
         addDirectory(directory)
 
@@ -359,12 +360,12 @@ object TiffReader {
      *
      * Discarding corrupt thumbnails is not a big issue, so no exceptions will be thrown here.
      */
-    private fun getJpegImageDataElement(
+    private fun readThumbnailBytes(
         byteReader: RandomAccessByteReader,
         directory: TiffDirectory
-    ): JpegImageDataElement? {
+    ): ByteArray? {
 
-        val element = directory.getJpegImageDataElement()
+        val element = directory.getJpegImageDataElement() ?: return null
 
         val offset = element.offset
         var length = element.length
@@ -401,37 +402,47 @@ object TiffReader {
          * there are some random bytes present.
          */
 
-        return JpegImageDataElement(offset, length, bytes)
+        return bytes
     }
 
-    private fun getStripImageDataElement(
+    private fun readTiffImageBytes(
         byteReader: RandomAccessByteReader,
         directory: TiffDirectory
-    ): TiffImageDataElement? {
+    ): ByteArray? {
 
-        val element = directory.getStripImageDataElement()
+        val elements = directory.getStripImageDataElements() ?: return null
 
-        val offset = element.offset
-        var length = element.length
+        val byteArrayByteWriter = ByteArrayByteWriter()
 
-        /*
-         * If the length is not correct (going beyond the file size) we need to adjust it.
-         */
-        if (offset + length > byteReader.contentLength)
-            length = (byteReader.contentLength - offset).toInt()
+        for (element in elements) {
 
-        /*
-         * If the new length is 0 or negative, ignore this element.
-         */
-        if (length <= 0)
-            return null
+            val offset = element.offset
+            var length = element.length
 
-        val bytes = byteReader.readBytes(offset.toInt(), length)
+            /*
+             * If the length is not correct (going beyond the file size) we need to adjust it.
+             */
+            if (offset + length > byteReader.contentLength)
+                length = (byteReader.contentLength - offset).toInt()
 
-        if (bytes.size != length)
-            return null
+            /*
+             * If the new length is 0 or negative, ignore this element.
+             */
+            if (length <= 0)
+                continue
+
+            val bytes = byteReader.readBytes(offset.toInt(), length)
+
+            /*
+             * Break if something is wrong.
+             */
+            if (bytes.size != length)
+                return null
+
+            byteArrayByteWriter.write(bytes)
+        }
 
-        return TiffImageDataElement(offset, length, bytes)
+        return byteArrayByteWriter.toByteArray()
     }
 
     /**