Refactorings & MakerNote support preparations (#64)

* Refactored APIs for more streamlined code
* Improved RAW support
* Prepared MakerNote support

README.md

@@ -21,10 +21,11 @@ It's part of [Ashampoo Photos](https://ashampoo.com/photos).
 * WebP: Read EXIF & XMP
 * HEIC / AVIF: Read EXIF & XMP
 * JPEG XL: Read EXIF & XMP of uncompressed files
-* TIFF / DNG / RAW: Read EXIF & XMP
-    + Good support for Canon CR2, Fujifilm RAF & Adobe DNG
-    + Experimental support for NEF, ARW, RW2 & ORF with known issues
-    + API for preview image extraction of DNG, CR2, RAF, NEF, ARW & RW2 (but not ORF)
+* TIFF / RAW: Read EXIF & XMP
+    + Full support for Adobe DNG, Canon CR2 & Fujifilm RAF
+    + Support for Nikon NEF, Sony ARW & Olympus ORF without lens info
+    + Support for Panasonic RW2 without lens info and image size
+    + API for preview image extraction of DNG, CR2, RAF, NEF, ARW & RW2
 * Handling of XMP content through
   [XMP Core for Kotlin Multiplatform](https://github.com/Ashampoo/xmpcore)
 * Convenient `Kim.update()` API to perform updates to the relevant places
@@ -36,7 +37,7 @@ of Ashampoo Photos, which, in turn, is driven by user community feedback.
 ## Installation
 
 ```
-implementation("com.ashampoo:kim:0.11")
+implementation("com.ashampoo:kim:0.12")
 ```
 
 ## Sample usages
@@ -141,8 +142,12 @@ val newBytes = Kim.updateThumbnail(
 ## Limitations
 
 * Inability to update EXIF, IPTC and XMP in JPG files simultaneously.
-* Does not read the image size and orientation for HEIC, AVIF & JPEG XL
-* Does not read brotli compressed metadata of JPEG XL due to missing brotli KMP libs
+* Does not read the image size and orientation for HEIC, AVIF & JPEG XL.
+* Does not read brotli compressed metadata of JPEG XL due to missing brotli KMP libs.
+* MakerNote support is experimental and limited.
+    + Can't extract preview image of ORF as offsets are burried into MakerNote.
+    + Can't identify lens info of NEF, ARW, RW2 & ORF because this is constructed from MakerNote fields.
+    + Missing image size for RW2 as this is also burried in MakerNotes.
 
 ### Regarding HEIC & AVIF metadata
 

src/commonMain/kotlin/com/ashampoo/kim/common/ByteConversions.kt

@@ -187,19 +187,19 @@ fun RationalNumber.toBytes(byteOrder: ByteOrder): ByteArray {
     return result
 }
 
-fun Array<out RationalNumber>.toBytes(byteOrder: ByteOrder): ByteArray =
-    this.toBytes(0, size, byteOrder)
+fun RationalNumbers.toBytes(byteOrder: ByteOrder): ByteArray =
+    this.toBytes(0, values.size, byteOrder)
 
-private fun Array<out RationalNumber>.toBytes(
+private fun RationalNumbers.toBytes(
     offset: Int,
     length: Int,
     byteOrder: ByteOrder
 ): ByteArray {
 
     val result = ByteArray(length * 8)
 
-    for (i in 0 until length)
-        this[offset + i].toBytes(byteOrder, result, i * 8)
+    for (index in 0 until length)
+        values[offset + index].toBytes(byteOrder, result, index * 8)
 
     return result
 }
@@ -402,7 +402,7 @@ private fun ByteArray.toRational(
 fun ByteArray.toRationals(
     byteOrder: ByteOrder,
     unsignedType: Boolean
-): Array<RationalNumber> =
+): RationalNumbers =
     toRationals(this, 0, size, byteOrder, unsignedType)
 
 private fun toRationals(
@@ -411,15 +411,15 @@ private fun toRationals(
     length: Int,
     byteOrder: ByteOrder,
     unsignedType: Boolean
-): Array<RationalNumber> {
+): RationalNumbers {
 
     val result = arrayOfNulls<RationalNumber>(length / 8)
 
     repeat(result.size) { i ->
         result[i] = bytes.toRational(offset + 8 * i, byteOrder, unsignedType)
     }
 
-    return result as Array<RationalNumber>
+    return RationalNumbers(result as Array<RationalNumber>)
 }
 
 fun Int.quadsToByteArray(): ByteArray {

src/commonMain/kotlin/com/ashampoo/kim/common/PhotoMetadataConverter.kt

@@ -51,7 +51,10 @@ fun ImageMetadata.convertToPhotoMetadata(
     val lensMake = findStringValue(ExifTag.EXIF_TAG_LENS_MAKE)
     val lensModel = findStringValue(ExifTag.EXIF_TAG_LENS_MODEL)
 
+    /* Look for ISO at the standard place and fall back to test RW2 logic. */
     val iso = findShortValue(ExifTag.EXIF_TAG_ISO)
+        ?: findShortValue(ExifTag.EXIF_TAG_ISO_PANASONIC)
+
     val exposureTime = findDoubleValue(ExifTag.EXIF_TAG_EXPOSURE_TIME)
     val fNumber = findDoubleValue(ExifTag.EXIF_TAG_FNUMBER)
     val focalLength = findDoubleValue(ExifTag.EXIF_TAG_FOCAL_LENGTH)

src/commonMain/kotlin/com/ashampoo/kim/common/RationalNumbers.kt

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2024 Ashampoo GmbH & Co. KG
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.ashampoo.kim.common
+
+/**
+ * To avoid rather unsafe "Array<*>" in instance checking we have this
+ * extra class to represent a collection of rational numbers.
+ */
+class RationalNumbers(
+    val values: Array<RationalNumber>
+) {
+
+    override fun toString(): String =
+        values.contentToString()
+
+    override fun hashCode(): Int =
+        values.contentHashCode()
+
+    override fun equals(other: Any?): Boolean {
+
+        if (this === other)
+            return true
+
+        if (other == null || this::class != other::class)
+            return false
+
+        other as RationalNumbers
+
+        return values.contentEquals(other.values)
+    }
+}

src/commonMain/kotlin/com/ashampoo/kim/format/ImageMetadata.kt

@@ -32,11 +32,6 @@ data class ImageMetadata(
     val xmp: String?
 ) {
 
-    fun getExifThumbnailBytes(): ByteArray? =
-        exif?.directories?.asSequence()
-            ?.mapNotNull { it.jpegImageDataElement?.bytes }
-            ?.firstOrNull()
-
     fun findStringValue(tagInfo: TagInfo): String? {
 
         val strings = findTiffField(tagInfo)?.value as? List<String>
@@ -49,25 +44,19 @@ data class ImageMetadata(
     }
 
     fun findShortValue(tagInfo: TagInfo): Short? =
-        findTiffField(tagInfo)?.value as? Short
+        findTiffField(tagInfo)?.toShort()
 
     fun findDoubleValue(tagInfo: TagInfo): Double? =
         findTiffField(tagInfo)?.toDouble()
 
-    /*
-     * Note: Keep in sync with TiffTags.getTag()
-     */
-    @Suppress("UnnecessaryParentheses")
-    fun findTiffField(tagInfo: TagInfo): TiffField? {
-        return exif?.directories?.firstOrNull { directory ->
-            directory.type == tagInfo.directoryType?.directoryType ||
-                (tagInfo.directoryType?.isImageDirectory == true && directory.type >= 0) ||
-                (tagInfo.directoryType?.isImageDirectory == false && directory.type < 0)
-        }?.findField(tagInfo)
-    }
+    fun findTiffField(tagInfo: TagInfo): TiffField? =
+        exif?.findTiffField(tagInfo)
 
     fun findTiffDirectory(directoryType: Int): TiffDirectory? =
-        exif?.directories?.find { it.type == directoryType }
+        exif?.findTiffDirectory(directoryType)
+
+    fun getExifThumbnailBytes(): ByteArray? =
+        exif?.getExifThumbnailBytes()
 
     override fun toString(): String {
 
@@ -76,15 +65,15 @@ data class ImageMetadata(
         sb.appendLine("Resolution  : $imageSize")
 
         if (exif != null)
-            sb.appendLine(exif)
+            sb.append(exif)
 
         if (iptc != null)
             sb.appendLine(iptc)
 
         if (xmp != null) {
 
             sb.appendLine("---- XMP ----")
-            sb.appendLine(xmp)
+            sb.append(xmp)
         }
 
         return sb.toString()

src/commonMain/kotlin/com/ashampoo/kim/format/cr2/Cr2PreviewExtractor.kt

@@ -19,7 +19,7 @@ import com.ashampoo.kim.common.ImageReadException
 import com.ashampoo.kim.common.tryWithImageReadException
 import com.ashampoo.kim.format.TiffPreviewExtractor
 import com.ashampoo.kim.format.tiff.TiffContents
-import com.ashampoo.kim.format.tiff.constant.TiffTag
+import com.ashampoo.kim.format.tiff.constant.ExifTag
 import com.ashampoo.kim.input.RandomAccessByteReader
 
 object Cr2PreviewExtractor : TiffPreviewExtractor {
@@ -33,10 +33,10 @@ object Cr2PreviewExtractor : TiffPreviewExtractor {
         val ifd0 = tiffContents.directories.first()
 
         val previewImageStart =
-            ifd0.getFieldValue(TiffTag.TIFF_TAG_STRIP_OFFSETS) ?: return null
+            ifd0.getFieldValue(ExifTag.EXIF_TAG_PREVIEW_IMAGE_START_IFD0) ?: return null
 
         val previewLength =
-            ifd0.getFieldValue(TiffTag.TIFF_TAG_STRIP_BYTE_COUNTS) ?: return null
+            ifd0.getFieldValue(ExifTag.EXIF_TAG_PREVIEW_IMAGE_LENGTH_IFD0) ?: return null
 
         if (previewLength == 0)
             return null

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

@@ -19,7 +19,7 @@ package com.ashampoo.kim.format.tiff
 import com.ashampoo.kim.common.GpsUtil.MINUTES_PER_HOUR
 import com.ashampoo.kim.common.GpsUtil.SECONDS_PER_HOUR
 import com.ashampoo.kim.common.ImageReadException
-import com.ashampoo.kim.common.RationalNumber
+import com.ashampoo.kim.common.RationalNumbers
 import com.ashampoo.kim.format.tiff.constant.GpsTag
 
 data class GPSInfo private constructor(
@@ -84,21 +84,21 @@ data class GPSInfo private constructor(
                 ?: return null
 
             // all of these values are strings.
-            val latitude = latitudeField.value as Array<RationalNumber>
-            val longitude = longitudeField.value as Array<RationalNumber>
+            val latitude = latitudeField.value as RationalNumbers
+            val longitude = longitudeField.value as RationalNumbers
 
-            if (latitude.size != 3 || longitude.size != 3)
+            if (latitude.values.size != 3 || longitude.values.size != 3)
                 throw ImageReadException("Expected three values for latitude and longitude.")
 
             return GPSInfo(
                 latitudeRef = latitudeRef,
                 longitudeRef = longitudeRef,
-                latitudeDegrees = latitude[0].doubleValue(),
-                latitudeMinutes = latitude[1].doubleValue(),
-                latitudeSeconds = latitude[2].doubleValue(),
-                longitudeDegrees = longitude[0].doubleValue(),
-                longitudeMinutes = longitude[1].doubleValue(),
-                longitudeSeconds = longitude[2].doubleValue()
+                latitudeDegrees = latitude.values[0].doubleValue(),
+                latitudeMinutes = latitude.values[1].doubleValue(),
+                latitudeSeconds = latitude.values[2].doubleValue(),
+                longitudeDegrees = longitude.values[0].doubleValue(),
+                longitudeMinutes = longitude.values[1].doubleValue(),
+                longitudeSeconds = longitude.values[2].doubleValue()
             )
         }
     }

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

@@ -16,13 +16,27 @@
  */
 package com.ashampoo.kim.format.tiff
 
+import com.ashampoo.kim.format.tiff.taginfo.TagInfo
 import com.ashampoo.kim.format.tiff.write.TiffOutputSet
 
 data class TiffContents(
     val header: TiffHeader,
-    val directories: List<TiffDirectory>
+    val directories: List<TiffDirectory>,
+    /** Artifical MakerNote directory */
+    val makerNoteDirectory: TiffDirectory?
 ) {
 
+    fun findTiffField(tagInfo: TagInfo): TiffField? =
+        TiffDirectory.findTiffField(directories, tagInfo)
+
+    fun findTiffDirectory(directoryType: Int): TiffDirectory? =
+        directories.find { it.type == directoryType }
+
+    fun getExifThumbnailBytes(): ByteArray? =
+        directories.asSequence()
+            .mapNotNull { it.jpegImageDataElement?.bytes }
+            .firstOrNull()
+
     fun createOutputSet(): TiffOutputSet {
 
         val result = TiffOutputSet(header.byteOrder)
@@ -54,6 +68,10 @@ data class TiffContents(
         for (directory in directories)
             sb.appendLine(directory)
 
+        makerNoteDirectory?.let {
+            sb.appendLine(makerNoteDirectory)
+        }
+
         return sb.toString()
     }
 }