Strip GPS/EXIF metadata when sharing photos (opt-in setting)

app/src/main/kotlin/org/fossify/gallery/activities/SettingsActivity.kt

@@ -62,6 +62,7 @@ class SettingsActivity : SimpleActivity() {
         setupManageHiddenFolders()
         setupSearchAllFiles()
         setupShowHiddenItems()
+        setupStripMetadataOnShare()
         setupAutoplayVideos()
         setupRememberLastVideo()
         setupLoopVideos()
@@ -260,6 +261,14 @@ class SettingsActivity : SimpleActivity() {
         config.showHiddenMedia = binding.settingsShowHiddenItems.isChecked
     }
 
+    private fun setupStripMetadataOnShare() {
+        binding.settingsStripMetadataOnShare.isChecked = config.stripMetadataOnShare
+        binding.settingsStripMetadataOnShareHolder.setOnClickListener {
+            binding.settingsStripMetadataOnShare.toggle()
+            config.stripMetadataOnShare = binding.settingsStripMetadataOnShare.isChecked
+        }
+    }
+
     private fun setupSearchAllFiles() {
         binding.settingsSearchAllFiles.isChecked = config.searchAllFilesByDefault
         binding.settingsSearchAllFilesHolder.setOnClickListener {

app/src/main/kotlin/org/fossify/gallery/extensions/Activity.kt

@@ -62,11 +62,25 @@ fun Activity.sharePaths(paths: ArrayList<String>) {
 }
 
 fun Activity.shareMediumPath(path: String) {
-    sharePath(path)
+    val finalPath = if (config.stripMetadataOnShare && org.fossify.gallery.helpers.MetadataStripper.isSupported(path)) {
+        org.fossify.gallery.helpers.MetadataStripper.stripToCacheCopy(this, path) ?: path
+    } else {
+        path
+    }
+    sharePath(finalPath)
 }
 
 fun Activity.shareMediaPaths(paths: ArrayList<String>) {
-    sharePaths(paths)
+    val finalPaths = if (config.stripMetadataOnShare) {
+        ArrayList(paths.map { sourcePath ->
+            if (org.fossify.gallery.helpers.MetadataStripper.isSupported(sourcePath)) {
+                org.fossify.gallery.helpers.MetadataStripper.stripToCacheCopy(this, sourcePath) ?: sourcePath
+            } else sourcePath
+        })
+    } else {
+        paths
+    }
+    sharePaths(finalPaths)
 }
 
 fun Activity.setAs(path: String) {

app/src/main/kotlin/org/fossify/gallery/helpers/Config.kt

@@ -602,4 +602,8 @@ class Config(context: Context) : BaseConfig(context) {
     var showPermissionRationale: Boolean
         get() = prefs.getBoolean(SHOW_PERMISSION_RATIONALE, false)
         set(showPermissionRationale) = prefs.edit().putBoolean(SHOW_PERMISSION_RATIONALE, showPermissionRationale).apply()
+
+    var stripMetadataOnShare: Boolean
+        get() = prefs.getBoolean(STRIP_METADATA_ON_SHARE, false)
+        set(value) = prefs.edit().putBoolean(STRIP_METADATA_ON_SHARE, value).apply()
 }

app/src/main/kotlin/org/fossify/gallery/helpers/Constants.kt

@@ -7,6 +7,7 @@ const val DIRECTORY_SORT_ORDER = "directory_sort_order"
 const val GROUP_FOLDER_PREFIX = "group_folder_"
 const val VIEW_TYPE_PREFIX = "view_type_folder_"
 const val SHOW_HIDDEN_MEDIA = "show_hidden_media"
+const val STRIP_METADATA_ON_SHARE = "strip_metadata_on_share"
 const val TEMPORARILY_SHOW_HIDDEN = "temporarily_show_hidden"
 const val TEMPORARILY_SHOW_EXCLUDED = "temporarily_show_excluded"
 const val EXCLUDED_PASSWORD_PROTECTION = "excluded_password_protection"

app/src/main/kotlin/org/fossify/gallery/helpers/MetadataStripper.kt

@@ -0,0 +1,83 @@
+package org.fossify.gallery.helpers
+
+import android.content.Context
+import androidx.exifinterface.media.ExifInterface
+import java.io.File
+import java.io.FileInputStream
+import java.io.FileOutputStream
+import java.util.Locale
+
+object MetadataStripper {
+    private val SENSITIVE_TAGS = arrayOf(
+        ExifInterface.TAG_GPS_LATITUDE,
+        ExifInterface.TAG_GPS_LATITUDE_REF,
+        ExifInterface.TAG_GPS_LONGITUDE,
+        ExifInterface.TAG_GPS_LONGITUDE_REF,
+        ExifInterface.TAG_GPS_ALTITUDE,
+        ExifInterface.TAG_GPS_ALTITUDE_REF,
+        ExifInterface.TAG_GPS_TIMESTAMP,
+        ExifInterface.TAG_GPS_DATESTAMP,
+        ExifInterface.TAG_GPS_PROCESSING_METHOD,
+        ExifInterface.TAG_GPS_AREA_INFORMATION,
+        ExifInterface.TAG_GPS_DEST_BEARING,
+        ExifInterface.TAG_GPS_DEST_BEARING_REF,
+        ExifInterface.TAG_GPS_DEST_DISTANCE,
+        ExifInterface.TAG_GPS_DEST_DISTANCE_REF,
+        ExifInterface.TAG_GPS_DEST_LATITUDE,
+        ExifInterface.TAG_GPS_DEST_LATITUDE_REF,
+        ExifInterface.TAG_GPS_DEST_LONGITUDE,
+        ExifInterface.TAG_GPS_DEST_LONGITUDE_REF,
+        ExifInterface.TAG_GPS_IMG_DIRECTION,
+        ExifInterface.TAG_GPS_IMG_DIRECTION_REF,
+        ExifInterface.TAG_GPS_SPEED,
+        ExifInterface.TAG_GPS_SPEED_REF,
+        ExifInterface.TAG_GPS_TRACK,
+        ExifInterface.TAG_GPS_TRACK_REF,
+        ExifInterface.TAG_DATETIME,
+        ExifInterface.TAG_DATETIME_ORIGINAL,
+        ExifInterface.TAG_DATETIME_DIGITIZED,
+        ExifInterface.TAG_OFFSET_TIME,
+        ExifInterface.TAG_OFFSET_TIME_ORIGINAL,
+        ExifInterface.TAG_OFFSET_TIME_DIGITIZED,
+        ExifInterface.TAG_MAKE,
+        ExifInterface.TAG_MODEL,
+        ExifInterface.TAG_SOFTWARE,
+        ExifInterface.TAG_ARTIST,
+        ExifInterface.TAG_COPYRIGHT,
+        ExifInterface.TAG_USER_COMMENT,
+        ExifInterface.TAG_IMAGE_DESCRIPTION,
+        ExifInterface.TAG_SUBJECT_LOCATION,
+        ExifInterface.TAG_SUBJECT_AREA,
+        ExifInterface.TAG_BODY_SERIAL_NUMBER,
+        ExifInterface.TAG_LENS_SERIAL_NUMBER,
+        ExifInterface.TAG_CAMERA_OWNER_NAME,
+    )
+
+    private val SUPPORTED_EXTENSIONS = setOf("jpg", "jpeg", "heic", "heif", "webp", "tiff", "tif", "png", "dng")
+
+    fun isSupported(path: String?): Boolean {
+        if (path.isNullOrBlank()) return false
+        val dotIndex = path.lastIndexOf('.')
+        if (dotIndex < 0) return false
+        val extension = path.substring(dotIndex + 1).lowercase(Locale.ROOT)
+        return extension in SUPPORTED_EXTENSIONS
+    }
+
+    fun stripToCacheCopy(context: Context, sourcePath: String): String? {
+        val source = File(sourcePath)
+        if (!source.exists() || !source.canRead()) return null
+        val cacheDir = File(context.cacheDir, "metadata-stripped").apply { mkdirs() }
+        val copy = File(cacheDir, "${System.currentTimeMillis()}-${source.name}")
+        FileInputStream(source).use { input ->
+            FileOutputStream(copy).use { output -> input.copyTo(output) }
+        }
+        runCatching {
+            val exif = ExifInterface(copy)
+            for (tag in SENSITIVE_TAGS) {
+                if (exif.getAttribute(tag) != null) exif.setAttribute(tag, null)
+            }
+            exif.saveAttributes()
+        }
+        return copy.absolutePath
+    }
+}

app/src/main/res/layout/activity_settings.xml

@@ -211,6 +211,21 @@
 
             </RelativeLayout>
 
+            <RelativeLayout
+                android:id="@+id/settings_strip_metadata_on_share_holder"
+                style="@style/SettingsHolderSwitchStyle"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content">
+
+                <org.fossify.commons.views.MyMaterialSwitch
+                    android:id="@+id/settings_strip_metadata_on_share"
+                    style="@style/SettingsSwitchStyle"
+                    android:layout_width="match_parent"
+                    android:layout_height="wrap_content"
+                    android:text="@string/strip_metadata_on_share" />
+
+            </RelativeLayout>
+
             <RelativeLayout
                 android:id="@+id/settings_search_all_files_holder"
                 style="@style/SettingsHolderSwitchStyle"

app/src/main/res/values/strings.xml

@@ -299,6 +299,7 @@
     <string name="faq_17_text">That stopped working due to the system changes that came with Android 11 too, the app cannot browse real folders anymore, it relies on the so called MediaStore at fetching data.</string>
     <string name="faq_18_title">Why do I see ads during video playback?</string>
     <string name="faq_18_text">Our apps have no ads whatsoever. If you see them during video playback, you must be using some other apps video player. Try finding your default video player in the device settings, then do a \"Clear defaults\" on it. The next time you invoke some video intent you will see an app picker prompt, where you can select what app you want to use.</string>
+    <string name="strip_metadata_on_share">Strip GPS/EXIF metadata when sharing photos</string>
     <!--
         Haven't found some strings? There's more at
         https://github.com/FossifyOrg/Commons/tree/master/commons/src/main/res