info: PNG IPTC display

android/app/src/main/kotlin/deckers/thibault/aves/channel/calls/MetadataFetchHandler.kt

@@ -34,16 +34,20 @@ import deckers.thibault.aves.metadata.ExifInterfaceHelper.getSafeRational
 import deckers.thibault.aves.metadata.MediaMetadataRetrieverHelper.getSafeDateMillis
 import deckers.thibault.aves.metadata.MediaMetadataRetrieverHelper.getSafeDescription
 import deckers.thibault.aves.metadata.MediaMetadataRetrieverHelper.getSafeInt
+import deckers.thibault.aves.metadata.Metadata.DIR_PNG_TEXTUAL_DATA
 import deckers.thibault.aves.metadata.Metadata.getRotationDegreesForExifCode
 import deckers.thibault.aves.metadata.Metadata.isFlippedForExifCode
+import deckers.thibault.aves.metadata.MetadataExtractorHelper.PNG_ITXT_DIR_NAME
 import deckers.thibault.aves.metadata.MetadataExtractorHelper.PNG_LAST_MODIFICATION_TIME_FORMAT
 import deckers.thibault.aves.metadata.MetadataExtractorHelper.PNG_TIME_DIR_NAME
+import deckers.thibault.aves.metadata.MetadataExtractorHelper.extractPngProfile
 import deckers.thibault.aves.metadata.MetadataExtractorHelper.getSafeBoolean
 import deckers.thibault.aves.metadata.MetadataExtractorHelper.getSafeDateMillis
 import deckers.thibault.aves.metadata.MetadataExtractorHelper.getSafeInt
 import deckers.thibault.aves.metadata.MetadataExtractorHelper.getSafeRational
 import deckers.thibault.aves.metadata.MetadataExtractorHelper.getSafeString
 import deckers.thibault.aves.metadata.MetadataExtractorHelper.isGeoTiff
+import deckers.thibault.aves.metadata.MetadataExtractorHelper.isPngTextDir
 import deckers.thibault.aves.metadata.XMP.getSafeDateMillis
 import deckers.thibault.aves.metadata.XMP.getSafeInt
 import deckers.thibault.aves.metadata.XMP.getSafeLocalizedText
@@ -53,12 +57,12 @@ import deckers.thibault.aves.metadata.XMP.isPanorama
 import deckers.thibault.aves.model.FieldMap
 import deckers.thibault.aves.utils.LogUtils
 import deckers.thibault.aves.utils.MimeTypes
+import deckers.thibault.aves.utils.MimeTypes.TIFF_EXTENSION_PATTERN
 import deckers.thibault.aves.utils.MimeTypes.canReadWithExifInterface
 import deckers.thibault.aves.utils.MimeTypes.canReadWithMetadataExtractor
 import deckers.thibault.aves.utils.MimeTypes.isHeic
 import deckers.thibault.aves.utils.MimeTypes.isImage
 import deckers.thibault.aves.utils.MimeTypes.isVideo
-import deckers.thibault.aves.utils.MimeTypes.tiffExtensionPattern
 import deckers.thibault.aves.utils.StorageUtils
 import deckers.thibault.aves.utils.UriUtils.tryParseId
 import io.flutter.plugin.common.MethodCall
@@ -143,7 +147,7 @@ class MetadataFetchHandler(private val context: Context) : MethodCallHandler {
                             // optional parent to distinguish child directories of the same type
                             dir.parent?.name?.let { thisDirName = "$it/$thisDirName" }
 
-                            val dirMap = metadataMap[thisDirName] ?: HashMap()
+                            var dirMap = metadataMap[thisDirName] ?: HashMap()
                             metadataMap[thisDirName] = dirMap
 
                             // tags
@@ -168,18 +172,35 @@ class MetadataFetchHandler(private val context: Context) : MethodCallHandler {
                                 } else {
                                     dirMap.putAll(tags.map { tagMapper(it) })
                                 }
-                            } else if (dir is PngDirectory) {
+                            } else if (dir.isPngTextDir()) {
+                                metadataMap.remove(thisDirName)
+                                dirMap = metadataMap[DIR_PNG_TEXTUAL_DATA] ?: HashMap()
+                                metadataMap[DIR_PNG_TEXTUAL_DATA] = dirMap
+
                                 for (tag in tags) {
                                     val tagType = tag.tagType
                                     if (tagType == PngDirectory.TAG_TEXTUAL_DATA) {
                                         val pairs = dir.getObject(tagType) as List<*>
-                                        dirMap.putAll(pairs.map {
+                                        val textPairs = pairs.map { pair ->
-                                            val kv = it as KeyValuePair
+                                            val kv = pair as KeyValuePair
-                                            // PNG spec says encoding charset is always Latin-1 / ISO-8859-1
+                                            val key = kv.key
-                                            // but in practice UTF-8 is sometimes used in PNG-iTXt chunks
+                                            // `PNG-iTXt` uses UTF-8, contrary to `PNG-tEXt` and `PNG-zTXt` using Latin-1 / ISO-8859-1
-                                            val charset = if (baseDirName == "PNG-iTXt") StandardCharsets.UTF_8 else kv.value.charset
+                                            val charset = if (baseDirName == PNG_ITXT_DIR_NAME) StandardCharsets.UTF_8 else kv.value.charset
-                                            Pair(kv.key, String(kv.value.bytes, charset))
+                                            val valueString = String(kv.value.bytes, charset)
-                                        })
+                                            val dirs = extractPngProfile(key, valueString)
+                                            if (dirs?.any() == true) {
+                                                dirs.forEach { profileDir ->
+                                                    val profileDirName = profileDir.name
+                                                    val profileDirMap = metadataMap[profileDirName] ?: HashMap()
+                                                    metadataMap[profileDirName] = profileDirMap
+                                                    profileDirMap.putAll(profileDir.tags.map { Pair(it.tagName, it.description) })
+                                                }
+                                                null
+                                            } else {
+                                                Pair(key, valueString)
+                                            }
+                                        }
+                                        dirMap.putAll(textPairs.filterNotNull())
                                     } else {
                                         dirMap[tag.tagName] = tag.description
                                     }
@@ -383,7 +404,7 @@ class MetadataFetchHandler(private val context: Context) : MethodCallHandler {
                         // In the end, `metadata-extractor` is the most reliable, except for `tiff` (false positives, false negatives),
                         // in which case we trust the file extension
                         // cf https://github.com/drewnoakes/metadata-extractor/issues/296
-                        if (path?.matches(tiffExtensionPattern) == true) {
+                        if (path?.matches(TIFF_EXTENSION_PATTERN) == true) {
                             metadataMap[KEY_MIME_TYPE] = MimeTypes.TIFF
                         } else {
                             dir.getSafeString(FileTypeDirectory.TAG_DETECTED_FILE_MIME_TYPE) {

android/app/src/main/kotlin/deckers/thibault/aves/channel/calls/fetchers/ThumbnailFetcher.kt

@@ -79,7 +79,7 @@ class ThumbnailFetcher internal constructor(
         } else {
             var errorDetails: String? = exception?.message
             if (errorDetails?.isNotEmpty() == true) {
-                errorDetails = errorDetails.split("\n".toRegex(), 2).first()
+                errorDetails = errorDetails.split(Regex("\n"), 2).first()
             }
             result.error("getThumbnail-null", "failed to get thumbnail for mimeType=$mimeType uri=$uri", errorDetails)
         }

android/app/src/main/kotlin/deckers/thibault/aves/channel/streams/ImageByteStreamHandler.kt

@@ -170,7 +170,7 @@ class ImageByteStreamHandler(private val activity: Activity, private val argumen
     private fun toErrorDetails(e: Exception): String? {
         val errorDetails = e.message
         return if (errorDetails?.isNotEmpty() == true) {
-            errorDetails.split("\n".toRegex(), 2).first()
+            errorDetails.split(Regex("\n"), 2).first()
         } else {
             errorDetails
         }

android/app/src/main/kotlin/deckers/thibault/aves/metadata/Metadata.kt

@@ -17,6 +17,8 @@ import java.util.regex.Pattern
 object Metadata {
     private val LOG_TAG = LogUtils.createTag<Metadata>()
 
+    const val IPTC_MARKER_BYTE: Byte = 0x1c
+
     // Pattern to extract latitude & longitude from a video location tag (cf ISO 6709)
     // Examples:
     // "+37.5090+127.0243/" (Samsung)
@@ -31,6 +33,7 @@ object Metadata {
     const val DIR_XMP = "XMP" // from metadata-extractor
     const val DIR_MEDIA = "Media" // custom
     const val DIR_COVER_ART = "Cover" // custom
+    const val DIR_PNG_TEXTUAL_DATA = "PNG Textual Data" // custom
 
     // types of metadata
     const val TYPE_EXIF = "exif"

android/app/src/main/kotlin/deckers/thibault/aves/metadata/MetadataExtractorHelper.kt

@@ -1,15 +1,27 @@
 package deckers.thibault.aves.metadata
 
 import com.drew.lang.Rational
+import com.drew.lang.SequentialByteArrayReader
 import com.drew.metadata.Directory
 import com.drew.metadata.exif.ExifIFD0Directory
+import com.drew.metadata.iptc.IptcReader
+import com.drew.metadata.png.PngDirectory
 import java.text.SimpleDateFormat
 import java.util.*
 
 object MetadataExtractorHelper {
+    const val PNG_ITXT_DIR_NAME = "PNG-iTXt"
+    private const val PNG_TEXT_DIR_NAME = "PNG-tEXt"
     const val PNG_TIME_DIR_NAME = "PNG-tIME"
+    private const val PNG_ZTXT_DIR_NAME = "PNG-zTXt"
+
     val PNG_LAST_MODIFICATION_TIME_FORMAT = SimpleDateFormat("yyyy:MM:dd HH:mm:ss", Locale.ROOT)
 
+    // Pattern to extract profile name, length, and text data
+    // of raw profiles (EXIF, IPTC, etc.) in PNG `zTXt` chunks
+    // e.g. "iptc [...] 114 [...] 3842494d040400[...]"
+    private val PNG_RAW_PROFILE_PATTERN = Regex("^\\n(.*?)\\n\\s*(\\d+)\\n(.*)", RegexOption.DOT_MATCHES_ALL)
+
     // extensions
 
     fun Directory.getSafeString(tag: Int, save: (value: String) -> Unit) {
@@ -59,4 +71,45 @@ object MetadataExtractorHelper {
 
         return true
     }
+
+    // PNG
+
+    fun Directory.isPngTextDir(): Boolean = this is PngDirectory && setOf(PNG_ITXT_DIR_NAME, PNG_TEXT_DIR_NAME, PNG_ZTXT_DIR_NAME).contains(this.name)
+
+    fun extractPngProfile(key: String, valueString: String): Iterable<Directory>? {
+        when (key) {
+            "Raw profile type iptc" -> {
+                val match = PNG_RAW_PROFILE_PATTERN.matchEntire(valueString)
+                if (match != null) {
+                    val dataString = match.groupValues[3]
+                    val hexString = dataString.replace(Regex("[\\r\\n]"), "")
+                    val dataBytes = hexStringToByteArray(hexString)
+                    if (dataBytes != null) {
+                        val start = dataBytes.indexOf(Metadata.IPTC_MARKER_BYTE)
+                        if (start != -1) {
+                            val segmentBytes = dataBytes.copyOfRange(fromIndex = start, toIndex = dataBytes.size - start)
+                            val metadata = com.drew.metadata.Metadata()
+                            IptcReader().extract(SequentialByteArrayReader(segmentBytes), metadata, segmentBytes.size.toLong())
+                            return metadata.directories
+                        }
+                    }
+                }
+            }
+        }
+        return null
+    }
+
+    // convenience methods
+
+    private fun hexStringToByteArray(hexString: String): ByteArray? {
+        if (hexString.length % 2 != 0) return null
+
+        val dataBytes = ByteArray(hexString.length / 2)
+        var i = 0
+        while (i < hexString.length) {
+            dataBytes[i / 2] = hexString.substring(i, i + 2).toByte(16)
+            i += 2
+        }
+        return dataBytes
+    }
 }

android/app/src/main/kotlin/deckers/thibault/aves/model/provider/ImageProvider.kt

@@ -122,7 +122,7 @@ abstract class ImageProvider {
 
         var desiredNameWithoutExtension = if (sourceEntry.path != null) {
             val sourceFileName = File(sourceEntry.path).name
-            sourceFileName.replaceFirst("[.][^.]+$".toRegex(), "")
+            sourceFileName.replaceFirst(FILE_EXTENSION_PATTERN, "")
         } else {
             sourceUri.lastPathSegment!!
         }
@@ -765,6 +765,8 @@ abstract class ImageProvider {
     companion object {
         private val LOG_TAG = LogUtils.createTag<ImageProvider>()
 
+        val FILE_EXTENSION_PATTERN = Regex("[.][^.]+$")
+
         val supportedExportMimeTypes = listOf(MimeTypes.BMP, MimeTypes.JPEG, MimeTypes.PNG, MimeTypes.WEBP)
 
         // used when skipping a move/creation op because the target file already exists

android/app/src/main/kotlin/deckers/thibault/aves/model/provider/MediaStoreImageProvider.kt

@@ -345,7 +345,7 @@ class MediaStoreImageProvider : ImageProvider() {
         }
 
         val sourceFileName = sourceFile.name
-        val desiredNameWithoutExtension = sourceFileName.replaceFirst("[.][^.]+$".toRegex(), "")
+        val desiredNameWithoutExtension = sourceFileName.replaceFirst(FILE_EXTENSION_PATTERN, "")
         val targetNameWithoutExtension = resolveTargetFileNameWithoutExtension(
             activity = activity,
             dir = destinationDir,

android/app/src/main/kotlin/deckers/thibault/aves/utils/LogUtils.kt

@@ -1,20 +1,20 @@
 package deckers.thibault.aves.utils
 
-import java.util.regex.Pattern
-
 object LogUtils {
     const val LOG_TAG_MAX_LENGTH = 23
-    val LOG_TAG_PACKAGE_PATTERN: Pattern = Pattern.compile("(\\w)(\\w*)\\.")
+
+    val LOG_TAG_PACKAGE_PATTERN = Regex("(\\w)(\\w*)\\.")
+    val LOWER_CASE_PATTERN = Regex("[a-z]")
 
     // create an Android logger friendly log tag for the specified class
     inline fun <reified T> createTag(): String {
         val kClass = T::class
         // shorten class name to "a.b.CccDdd"
-        var logTag = LOG_TAG_PACKAGE_PATTERN.matcher(kClass.qualifiedName!!).replaceAll("$1.")
+        var logTag = LOG_TAG_PACKAGE_PATTERN.replace(kClass.qualifiedName!!, "$1.")
         if (logTag.length > LOG_TAG_MAX_LENGTH) {
             // shorten class name to "a.b.CD"
             val simpleName = kClass.simpleName!!
-            val shortSimpleName = simpleName.replace("[a-z]".toRegex(), "")
+            val shortSimpleName = simpleName.replace(LOWER_CASE_PATTERN, "")
             logTag = logTag.replace(simpleName, shortSimpleName)
             if (logTag.length > LOG_TAG_MAX_LENGTH) {
                 // shorten class name to "CD"

android/app/src/main/kotlin/deckers/thibault/aves/utils/MimeTypes.kt

@@ -180,5 +180,5 @@ object MimeTypes {
         else -> null
     }
 
-    val tiffExtensionPattern = Regex(".*\\.tiff?", RegexOption.IGNORE_CASE)
+    val TIFF_EXTENSION_PATTERN = Regex(".*\\.tiff?", RegexOption.IGNORE_CASE)
 }

android/app/src/main/kotlin/deckers/thibault/aves/utils/StorageUtils.kt

@@ -29,6 +29,9 @@ import java.util.regex.Pattern
 object StorageUtils {
     private val LOG_TAG = LogUtils.createTag<StorageUtils>()
 
+    private const val TREE_URI_ROOT = "content://com.android.externalstorage.documents/tree/"
+    private val TREE_URI_PATH_PATTERN = Pattern.compile("(.*?):(.*)")
+
     /**
      * Volume paths
      */
@@ -269,8 +272,8 @@ object StorageUtils {
     // content://com.android.externalstorage.documents/tree/primary%3A              -> /storage/emulated/0/
     // content://com.android.externalstorage.documents/tree/10F9-3F13%3APictures    -> /storage/10F9-3F13/Pictures/
     fun convertTreeUriToDirPath(context: Context, treeUri: Uri): String? {
-        val encoded = treeUri.toString().substring("content://com.android.externalstorage.documents/tree/".length)
+        val encoded = treeUri.toString().substring(TREE_URI_ROOT.length)
-        val matcher = Pattern.compile("(.*?):(.*)").matcher(Uri.decode(encoded))
+        val matcher = TREE_URI_PATH_PATTERN.matcher(Uri.decode(encoded))
         with(matcher) {
             if (find()) {
                 val uuid = group(1)