JXR: added support to EXIF metadata

Improved metadata support via EXIF ​​metadata. Since JXR is based on a TIFF container, EXIF ​​data is read directly from the file so it always works (even with versions of libjxr that don't have the metadata reading API).

It also solves the following issues:
- Incorrect date format on saved JXR files (was saved in ISO format instead of `yyyy:MM:dd HH:mm:ss`).
- Incorrect date type setting in EXIF ​​data: the `DateTime` tag should be updated on every save (verified by GIMP and Photoshop). Our `CreationDate` metadata is the equivalent of the EXIF ​​`DateTimeOriginal` tag.

Closes #22

README.md

@@ -125,8 +125,9 @@ About the image:
   example a verbal description of the image.
 - `Copyright`: Copyright notice of the person or organization that claims 
   the copyright to the image.
-- `CreationDate`: Creation date and time in ISO 8601 format without 
+- `CreationDate`: When the image was created or captured. Date and time in 
-  milliseconds (e.g. 2024-03-23T15:30:43).
+  ISO 8601 format without milliseconds (e.g. 2024-03-23T15:30:43). This value
+  should be kept unchanged when present.
 - `Description`: A string that describes the subject of the image.
 - `DocumentName`: The name of the document from which this image was 
   scanned.
@@ -136,6 +137,9 @@ About the image:
   north of the equator (e.g. 27.717).
 - `Longitude`: Floating-point number indicating the longitude in degrees 
   east of Greenwich (e.g. 85.317).
+- `ModificationDate`: Last modification date and time in ISO 8601 format 
+  without milliseconds (e.g. 2024-03-23T15:30:43). This value should be 
+  updated every time the image is saved.
 - `Owner`: Name of the owner of the image.
 - `Software`: Name and version number of the software package(s) used to 
   create the image.
@@ -189,6 +193,7 @@ are created automatically:
 - `Software`: Created using `applicationName` and `applicationVersion` methods
   of [`QCoreApplication`](https://doc.qt.io/qt-6/qcoreapplication.html).
 - `CreationDate`: Set to current time and date.
+- `ModificationDate`: Set to current time and date.
 
 ### ICC profile support
 

autotests/read/avif/metadata.avif.json

@@ -3,7 +3,7 @@
         "fileName" : "metadata.png",
         "metadata" : [
             {
-                "key" : "CreationDate",
+                "key" : "ModificationDate",
                 "value" : "2025-02-19T08:27:22+01:00"
             },
             {

autotests/read/jxl/gimp_exif.jxl.json

@@ -3,7 +3,7 @@
         "fileName" : "gimp_exif.png",
         "metadata" : [
             {
-                "key" : "CreationDate",
+                "key" : "ModificationDate",
                 "value" : "2025-01-05T10:18:16"
             },
             {

autotests/read/jxr/metadata.jxr.json

@@ -0,0 +1,59 @@
+[
+    {
+        "fileName" : "metadata.png",
+        "metadata" : [
+            {
+                "key" : "CreationDate",
+                "value" : "2025-01-14T10:34:51Z"
+            },
+            {
+                "key" : "Software" ,
+                "value" : "LIFE Pro 2.18.10"
+            },
+            {
+                "key" : "Altitude",
+                "value" : "34"
+            },
+            {
+                "key" : "Author",
+                "value" : "KDE Project"
+            },
+            {
+                "key" : "Copyright",
+                "value" : "@2025 KDE Project"
+            },
+            {
+                "key" : "Description",
+                "value" : "TV broadcast test image."
+            },
+            {
+                "key" : "Latitude",
+                "value" : "44.6478"
+            },
+            {
+                "key" : "LensManufacturer",
+                "value" : "KDE Glasses"
+            },
+            {
+                "key" : "LensModel",
+                "value" : "A1234"
+            },
+            {
+                "key" : "Longitude",
+                "value" : "10.9254"
+            },
+            {
+                "key" : "Manufacturer",
+                "value" : "KFramework"
+            },
+            {
+                "key" : "Model",
+                "value" : "KImageFormats"
+            }
+        ],
+        "resolution" : {
+            "dotsPerMeterX" : 11811,
+            "dotsPerMeterY" : 5906
+        }
+    }
+]

autotests/read/psd/mch-16bits.psd.json

@@ -8,7 +8,7 @@
         },
         "metadata" : [
             {
-                "key" : "CreationDate",
+                "key" : "ModificationDate",
                 "value" : "2022-11-11T14:27:52"
             },
             {

autotests/read/psd/mch-8bits.psd.json

@@ -8,7 +8,7 @@
         },
         "metadata" : [
             {
-                "key" : "CreationDate",
+                "key" : "ModificationDate",
                 "value" : "2022-11-11T14:27:39"
             },
             {

autotests/read/psd/metadata.psd.json

@@ -3,7 +3,7 @@
         "fileName" : "metadata.png",
         "metadata" : [
             {
-                "key" : "CreationDate",
+                "key" : "ModificationDate",
                 "value" : "2025-01-14T13:53:32+01:00"
             },
             {

autotests/write/basic/avif.json

@@ -5,6 +5,10 @@
             "key" : "CreationDate",
             "value" : "2025-01-14T13:53:32+01:00"
         },
+        {
+            "key" : "ModificationDate",
+            "value" : "2025-02-14T15:58:44+01:00"
+        },
         {
             "key" : "Software" ,
             "value" : "Adobe Photoshop 26.2 (Windows)"

autotests/write/basic/jxl.json

@@ -5,6 +5,10 @@
             "key" : "CreationDate",
             "value" : "2025-01-14T13:53:32+01:00"
         },
+        {
+            "key" : "ModificationDate",
+            "value" : "2025-02-14T15:58:44+01:00"
+        },
         {
             "key" : "Software" ,
             "value" : "Adobe Photoshop 26.2 (Windows)"

autotests/write/basic/jxr.json

@@ -5,6 +5,14 @@
             "key" : "CreationDate",
             "value" : "2025-01-14T13:53:32+01:00"
         },
+        {
+            "key" : "ModificationDate",
+            "value" : "2025-02-14T15:58:44+01:00"
+        },
+        {
+            "key" : "Altitude",
+            "value" : "34"
+        },
         {
             "key" : "Author",
             "value" : "KDE Project"
@@ -17,6 +25,22 @@
             "key" : "Description",
             "value" : "TV broadcast test image."
         },
+        {
+            "key" : "Latitude",
+            "value" : "44.6478"
+        },
+        {
+            "key" : "LensManufacturer",
+            "value" : "KDE Glasses"
+        },
+        {
+            "key" : "LensModel",
+            "value" : "A1234"
+        },
+        {
+            "key" : "Longitude",
+            "value" : "10.9254"
+        },
         {
             "key" : "Manufacturer",
             "value" : "KFramework"

src/imageformats/CMakeLists.txt

@@ -140,7 +140,7 @@ endif()
 ##################################
 
 if (LibJXR_FOUND)
-    kimageformats_add_plugin(kimg_jxr SOURCES jxr.cpp)
+    kimageformats_add_plugin(kimg_jxr SOURCES jxr.cpp microexif.cpp)
     kde_enable_exceptions()
     target_include_directories(kimg_jxr PRIVATE ${LIBJXR_INCLUDE_DIRS})
     target_link_libraries(kimg_jxr PRIVATE ${LIBJXR_LIBRARIES})

src/imageformats/jxr.cpp

@@ -15,6 +15,7 @@
  */
 
 #include "jxr_p.h"
+#include "microexif_p.h"
 #include "util_p.h"
 
 #include <QColorSpace>
@@ -83,9 +84,10 @@ Q_LOGGING_CATEGORY(LOG_JXRPLUGIN, "kf.imageformats.plugins.jxr", QtWarningMsg)
 class JXRHandlerPrivate : public QSharedData
 {
 private:
-    QSharedPointer<QTemporaryDir> tempDir;
+    QSharedPointer<QTemporaryDir> m_tempDir;
-    mutable QSharedPointer<QFile> jxrFile;
+    QSharedPointer<QFile> m_jxrFile;
-    mutable QHash<QString, QString> txtMeta;
+    MicroExif m_exif;
+    mutable QHash<QString, QString> m_txtMeta;
 
 public:
     PKFactory *pFactory = nullptr;
@@ -95,7 +97,7 @@ public:
 
     JXRHandlerPrivate()
     {
-        tempDir = QSharedPointer<QTemporaryDir>(new QTemporaryDir);
+        m_tempDir = QSharedPointer<QTemporaryDir>(new QTemporaryDir);
         if (PKCreateFactory(&pFactory, PK_SDK_VERSION) == WMP_errSuccess) {
             PKCreateCodecFactory(&pCodecFactory, WMP_SDK_VERSION);
         }
@@ -123,7 +125,7 @@ public:
 
     QString fileName() const
     {
-        return jxrFile->fileName();
+        return m_jxrFile->fileName();
     }
 
     /* *** READ *** */
@@ -318,11 +320,20 @@ public:
     }
 
     /*!
-     * \brief setTextMetadata
+     * \brief exifData
-     * Set the text metadata into \a image
+     * \return The EXIF data.
+     */
+    MicroExif exifData() const
+    {
+        return m_exif;
+    }
+
+    /*!
+     * \brief setMetadata
+     * Set the metadata into \a image
      * \param image Image on which to write metadata
      */
-    void setTextMetadata(QImage& image)
+    void setMetadata(QImage& image)
     {
         auto xmp = xmpData();
         if (!xmp.isEmpty()) {
@@ -344,10 +355,6 @@ public:
         if (!model.isEmpty()) {
             image.setText(QStringLiteral(META_KEY_MODEL), model);
         }
-        auto cDate = dateTime();
-        if (!cDate.isEmpty()) {
-            image.setText(QStringLiteral(META_KEY_CREATIONDATE), cDate);
-        }
         auto author = artist();
         if (!author.isEmpty()) {
             image.setText(QStringLiteral(META_KEY_AUTHOR), author);
@@ -368,20 +375,23 @@ public:
         if (!docn.isEmpty()) {
             image.setText(QStringLiteral(META_KEY_DOCUMENTNAME), docn);
         }
+        auto exif = exifData();
+        if (!exif.isEmpty()) {
+            exif.toImageMetadata(image);
+        }
     }
 
 #define META_TEXT(name, key)                                                                                                                                   \
     QString name() const                                                                                                                                       \
     {                                                                                                                                                          \
         readTextMeta();                                                                                                                                        \
-        return txtMeta.value(QStringLiteral(key));                                                                                                             \
+        return m_txtMeta.value(QStringLiteral(key));                                                                                                           \
     }
 
     META_TEXT(description, META_KEY_DESCRIPTION)
     META_TEXT(cameraMake, META_KEY_MANUFACTURER)
     META_TEXT(cameraModel, META_KEY_MODEL)
     META_TEXT(software, META_KEY_SOFTWARE)
-    META_TEXT(dateTime, META_KEY_CREATIONDATE)
     META_TEXT(artist, META_KEY_AUTHOR)
     META_TEXT(copyright, META_KEY_COPYRIGHT)
     META_TEXT(caption, META_KEY_TITLE)
@@ -400,9 +410,9 @@ public:
     bool initForWriting()
     {
         // I have to use QFile because, on Windows, the QTemporary file is locked (even if I close it)
-        auto fileName = QStringLiteral("%1.jxr").arg(tempDir->filePath(QUuid::createUuid().toString(QUuid::WithoutBraces).left(8)));
+        auto fileName = QStringLiteral("%1.jxr").arg(m_tempDir->filePath(QUuid::createUuid().toString(QUuid::WithoutBraces).left(8)));
         QSharedPointer<QFile> file(new QFile(fileName));
-        jxrFile = file;
+        m_jxrFile = file;
         return initEncoder();
     }
 
@@ -422,7 +432,7 @@ public:
             return false;
         }
 
-        if (!deviceCopy(device, jxrFile.data())) {
+        if (!deviceCopy(device, m_jxrFile.data())) {
             qCWarning(LOG_JXRPLUGIN) << "JXRHandlerPrivate::finalizeWriting() error while writing in the target device";
             return false;
         }
@@ -580,7 +590,6 @@ public:
         META_CTEXT(META_KEY_MODEL, pvarCameraModel)
         META_CTEXT(META_KEY_AUTHOR, pvarArtist)
         META_CTEXT(META_KEY_COPYRIGHT, pvarCopyright)
-        META_CTEXT(META_KEY_CREATIONDATE, pvarDateTime)
         META_CTEXT(META_KEY_DOCUMENTNAME, pvarDocumentName)
         META_CTEXT(META_KEY_HOSTCOMPUTER, pvarHostComputer)
         META_WTEXT(META_KEY_TITLE, pvarCaption)
@@ -595,12 +604,33 @@ public:
             meta.pvarSoftware.VT.pszVal = software.data();
         }
 
+        // Date and Time (TIFF format)
+        auto cDate = QDateTime::fromString(image.text(QStringLiteral(META_KEY_MODIFICATIONDATE)), Qt::ISODate);
+        auto sDate = cDate.isValid() ? cDate.toString(QStringLiteral("yyyy:MM:dd HH:mm:ss")).toLatin1() : QByteArray();
+        if (!sDate.isEmpty()) {
+            meta.pvarDateTime.vt = DPKVT_LPSTR;
+            meta.pvarDateTime.VT.pszVal = sDate.data();
+        }
+
         auto xmp = image.text(QStringLiteral(META_KEY_XMP_ADOBE)).toUtf8();
         if (!xmp.isNull()) {
-            if (auto err = PKImageEncode_SetXMPMetadata_WMP(pEncoder, reinterpret_cast<quint8 *>(xmp.data()), xmp.size())) {
+            if (auto err = PKImageEncode_SetXMPMetadata_WMP(pEncoder, reinterpret_cast<const quint8 *>(xmp.constData()), xmp.size())) {
                 qCWarning(LOG_JXRPLUGIN) << "JXRHandler::write() error while setting XMP data:" << err;
             }
         }
+
+        auto exif = MicroExif::fromImage(image);
+        if (!exif.isEmpty()) {
+            auto exifIfd = exif.exifIfdByteArray(QDataStream::LittleEndian);
+            if (auto err = PKImageEncode_SetEXIFMetadata_WMP(pEncoder, reinterpret_cast<const quint8 *>(exifIfd.constData()), exifIfd.size())) {
+                qCWarning(LOG_JXRPLUGIN) << "JXRHandler::write() error while setting EXIF data:" << err;
+            }
+            auto gpsIfd = exif.gpsIfdByteArray(QDataStream::LittleEndian);
+            if (auto err = PKImageEncode_SetGPSInfoMetadata_WMP(pEncoder, reinterpret_cast<const quint8 *>(gpsIfd.constData()), gpsIfd.size())) {
+                qCWarning(LOG_JXRPLUGIN) << "JXRHandler::write() error while setting GPS data:" << err;
+            }
+        }
+
         if (auto err = pEncoder->SetDescriptiveMetadata(pEncoder, &meta)) {
             qCWarning(LOG_JXRPLUGIN) << "JXRHandler::write() error while setting descriptive data:" << err;
         }
@@ -710,11 +740,11 @@ private:
         if (device == nullptr) {
             return false;
         }
-        if (!jxrFile.isNull()) {
+        if (!m_jxrFile.isNull()) {
             return true;
         }
         // I have to use QFile because, on Windows, the QTemporary file is locked (even if I close it)
-        auto fileName = QStringLiteral("%1.jxr").arg(tempDir->filePath(QUuid::createUuid().toString(QUuid::WithoutBraces).left(8)));
+        auto fileName = QStringLiteral("%1.jxr").arg(m_tempDir->filePath(QUuid::createUuid().toString(QUuid::WithoutBraces).left(8)));
         QSharedPointer<QFile> file(new QFile(fileName));
         if (!file->open(QFile::WriteOnly)) {
             return false;
@@ -724,7 +754,8 @@ private:
             return false;
         }
         file->close();
-        jxrFile = file;
+        m_exif = MicroExif::fromDevice(file.data());
+        m_jxrFile = file;
         return true;
     }
 
@@ -762,7 +793,7 @@ private:
         if (pDecoder == nullptr) {
             return false;
         }
-        if (!txtMeta.isEmpty()) {
+        if (!m_txtMeta.isEmpty()) {
             return true;
         }
 
@@ -773,15 +804,14 @@ private:
 
 #define META_TEXT(name, field)                                                                                                                                 \
     if (meta.field.vt == DPKVT_LPSTR)                                                                                                                          \
-        txtMeta.insert(QStringLiteral(name), QString::fromUtf8(meta.field.VT.pszVal));                                                                         \
+        m_txtMeta.insert(QStringLiteral(name), QString::fromUtf8(meta.field.VT.pszVal));                                                                       \
     else if (meta.field.vt == DPKVT_LPWSTR)                                                                                                                    \
-        txtMeta.insert(QStringLiteral(name), QString::fromUtf16(reinterpret_cast<char16_t *>(meta.field.VT.pwszVal)));
+        m_txtMeta.insert(QStringLiteral(name), QString::fromUtf16(reinterpret_cast<char16_t *>(meta.field.VT.pwszVal)));
 
         META_TEXT(META_KEY_DESCRIPTION, pvarImageDescription)
         META_TEXT(META_KEY_MANUFACTURER, pvarCameraMake)
         META_TEXT(META_KEY_MODEL, pvarCameraModel)
         META_TEXT(META_KEY_SOFTWARE, pvarSoftware)
-        META_TEXT(META_KEY_CREATIONDATE, pvarDateTime)
         META_TEXT(META_KEY_AUTHOR, pvarArtist)
         META_TEXT(META_KEY_COPYRIGHT, pvarCopyright)
         META_TEXT(META_KEY_TITLE, pvarCaption)
@@ -867,7 +897,7 @@ bool JXRHandler::read(QImage *outImage)
 
     // Metadata (e.g.: icc profile, description, etc...)
     img.setColorSpace(d->colorSpace());
-    d->setTextMetadata(img);
+    d->setMetadata(img);
 
 #ifndef JXR_DENY_FLOAT_IMAGE
     // JXR float are stored in scRGB.

src/imageformats/microexif.cpp

@@ -37,7 +37,12 @@
 // EXIF 3 specs
 #define EXIF_EXIFIFD 0x8769
 #define EXIF_GPSIFD 0x8825
+#define EXIF_EXIFVERSION 0x9000
+#define EXIF_DATETIMEORIGINAL 0x9003
+#define EXIF_DATETIMEDIGITIZED 0x9004
 #define EXIF_OFFSETTIME 0x9010
+#define EXIF_OFFSETTIMEORIGINAL 0x9011
+#define EXIF_OFFSETTIMEDIGITIZED 0x9012
 #define EXIF_COLORSPACE 0xA001
 #define EXIF_PIXELXDIM 0xA002
 #define EXIF_PIXELYDIM 0xA003
@@ -47,7 +52,6 @@
 #define EXIF_LENSMODEL 0xA434
 #define EXIF_LENSSERIALNUMBER 0xA435
 #define EXIF_IMAGETITLE 0xA436
-#define EXIF_EXIFVERSION 0x9000
 
 #define EXIF_VAL_COLORSPACE_SRGB 1
 #define EXIF_VAL_COLORSPACE_UNCAL 0xFFFF
@@ -119,7 +123,11 @@ static const KnownTags staticTagTypes = {
     TagInfo(TIFF_COPYRIGHT, ExifTagType::Ascii),
     TagInfo(EXIF_EXIFIFD, ExifTagType::Long),
     TagInfo(EXIF_GPSIFD, ExifTagType::Long),
+    TagInfo(EXIF_DATETIMEORIGINAL, ExifTagType::Ascii),
+    TagInfo(EXIF_OFFSETTIMEDIGITIZED, ExifTagType::Ascii),
     TagInfo(EXIF_OFFSETTIME, ExifTagType::Ascii),
+    TagInfo(EXIF_OFFSETTIMEORIGINAL, ExifTagType::Ascii),
+    TagInfo(EXIF_OFFSETTIMEDIGITIZED, ExifTagType::Ascii),
     TagInfo(EXIF_COLORSPACE, ExifTagType::Short),
     TagInfo(EXIF_PIXELXDIM, ExifTagType::Long),
     TagInfo(EXIF_PIXELYDIM, ExifTagType::Long),
@@ -230,8 +238,8 @@ static bool checkHeader(QDataStream &ds)
 
     quint16 version;
     ds >> version;
-    if (version != 0x2A)
+    if (version != 0x002A && version != 0x01BC)
-        return false;
+        return false; // not TIFF or JXR
 
     quint32 offset;
     ds >> offset;
@@ -852,6 +860,46 @@ void MicroExif::setDateTime(const QDateTime &dt)
     setExifString(EXIF_OFFSETTIME, timeOffset(dt.offsetFromUtc() / 60));
 }
 
+QDateTime MicroExif::dateTimeOriginal() const
+{
+    auto dt = QDateTime::fromString(exifString(EXIF_DATETIMEORIGINAL), QStringLiteral("yyyy:MM:dd HH:mm:ss"));
+    auto ofTag = exifString(EXIF_OFFSETTIMEORIGINAL);
+    if (dt.isValid() && !ofTag.isEmpty())
+        dt.setTimeZone(QTimeZone::fromSecondsAheadOfUtc(timeOffset(ofTag) * 60));
+    return(dt);
+}
+
+void MicroExif::setDateTimeOriginal(const QDateTime &dt)
+{
+    if (!dt.isValid()) {
+        m_exifTags.remove(EXIF_DATETIMEORIGINAL);
+        m_exifTags.remove(EXIF_OFFSETTIMEORIGINAL);
+        return;
+    }
+    setExifString(EXIF_DATETIMEORIGINAL, dt.toString(QStringLiteral("yyyy:MM:dd HH:mm:ss")));
+    setExifString(EXIF_OFFSETTIMEORIGINAL, timeOffset(dt.offsetFromUtc() / 60));
+}
+
+QDateTime MicroExif::dateTimeDigitized() const
+{
+    auto dt = QDateTime::fromString(exifString(EXIF_DATETIMEDIGITIZED), QStringLiteral("yyyy:MM:dd HH:mm:ss"));
+    auto ofTag = exifString(EXIF_OFFSETTIMEDIGITIZED);
+    if (dt.isValid() && !ofTag.isEmpty())
+        dt.setTimeZone(QTimeZone::fromSecondsAheadOfUtc(timeOffset(ofTag) * 60));
+    return(dt);
+}
+
+void MicroExif::setDateTimeDigitized(const QDateTime &dt)
+{
+    if (!dt.isValid()) {
+        m_exifTags.remove(EXIF_DATETIMEDIGITIZED);
+        m_exifTags.remove(EXIF_OFFSETTIMEDIGITIZED);
+        return;
+    }
+    setExifString(EXIF_DATETIMEDIGITIZED, dt.toString(QStringLiteral("yyyy:MM:dd HH:mm:ss")));
+    setExifString(EXIF_OFFSETTIMEDIGITIZED, timeOffset(dt.offsetFromUtc() / 60));
+}
+
 QString MicroExif::title() const
 {
     return exifString(EXIF_IMAGETITLE);
@@ -956,6 +1004,50 @@ QByteArray MicroExif::toByteArray(const QDataStream::ByteOrder &byteOrder) const
     return ba;
 }
 
+QByteArray MicroExif::exifIfdByteArray(const QDataStream::ByteOrder &byteOrder) const
+{
+    QByteArray ba;
+    {
+        QDataStream ds(&ba, QIODevice::WriteOnly);
+        ds.setByteOrder(byteOrder);
+        auto exifTags = m_exifTags;
+        exifTags.insert(EXIF_EXIFVERSION, QByteArray("0300"));
+        TagPos positions;
+        if (!writeIfd(ds, exifTags, positions))
+            return {};
+    }
+    return ba;
+}
+
+bool MicroExif::setExifIfdByteArray(const QByteArray &ba, const QDataStream::ByteOrder &byteOrder)
+{
+    QDataStream ds(ba);
+    ds.setByteOrder(byteOrder);
+    return readIfd(ds, m_exifTags, 0, staticTagTypes);
+}
+
+QByteArray MicroExif::gpsIfdByteArray(const QDataStream::ByteOrder &byteOrder) const
+{
+    QByteArray ba;
+    {
+        QDataStream ds(&ba, QIODevice::WriteOnly);
+        ds.setByteOrder(byteOrder);
+        auto gpsTags = m_gpsTags;
+        gpsTags.insert(GPS_GPSVERSION, QByteArray("2400"));
+        TagPos positions;
+        if (!writeIfd(ds, gpsTags, positions, 0, staticGpsTagTypes))
+            return {};
+        return ba;
+    }
+}
+
+bool MicroExif::setGpsIfdByteArray(const QByteArray &ba, const QDataStream::ByteOrder &byteOrder)
+{
+    QDataStream ds(ba);
+    ds.setByteOrder(byteOrder);
+    return readIfd(ds, m_gpsTags, 0, staticGpsTagTypes);
+}
+
 bool MicroExif::write(QIODevice *device, const QDataStream::ByteOrder &byteOrder) const
 {
     if (device == nullptr || device->isSequential() || isEmpty())
@@ -993,8 +1085,13 @@ void MicroExif::toImageMetadata(QImage &targetImage, bool replaceExisting) const
     }
 
     // set date and time
-    if (replaceExisting || targetImage.text(QStringLiteral(META_KEY_CREATIONDATE)).isEmpty()) {
+    if (replaceExisting || targetImage.text(QStringLiteral(META_KEY_MODIFICATIONDATE)).isEmpty()) {
         auto dt = dateTime();
+        if (dt.isValid())
+            targetImage.setText(QStringLiteral(META_KEY_MODIFICATIONDATE), dt.toString(Qt::ISODate));
+    }
+    if (replaceExisting || targetImage.text(QStringLiteral(META_KEY_CREATIONDATE)).isEmpty()) {
+        auto dt = dateTimeOriginal();
         if (dt.isValid())
             targetImage.setText(QStringLiteral(META_KEY_CREATIONDATE), dt.toString(Qt::ISODate));
     }
@@ -1095,12 +1192,18 @@ MicroExif MicroExif::fromImage(const QImage &image)
         exif.setSoftware(sw.trimmed());
     }
 
-    // TIFF Creation date and time
+    // TIFF date and time
-    auto dt = QDateTime::fromString(image.text(QStringLiteral(META_KEY_CREATIONDATE)), Qt::ISODate);
+    auto dt = QDateTime::fromString(image.text(QStringLiteral(META_KEY_MODIFICATIONDATE)), Qt::ISODate);
     if (!dt.isValid())
         dt = QDateTime::currentDateTime();
     exif.setDateTime(dt);
 
+    // EXIF original date and time
+    dt = QDateTime::fromString(image.text(QStringLiteral(META_KEY_CREATIONDATE)), Qt::ISODate);
+    if (!dt.isValid())
+        dt = QDateTime::currentDateTime();
+    exif.setDateTimeOriginal(dt);
+
     // GPS Info
     auto ok = false;
     auto alt = image.text(QStringLiteral(META_KEY_ALTITUDE)).toDouble(&ok);

src/imageformats/microexif_p.h

@@ -201,6 +201,20 @@ public:
     QDateTime dateTime() const;
     void setDateTime(const QDateTime& dt);
 
+    /*!
+     * \brief dateTimeOriginal
+     * \return The date and time when the original image data was generated.
+     */
+    QDateTime dateTimeOriginal() const;
+    void setDateTimeOriginal(const QDateTime& dt);
+
+    /*!
+     * \brief dateTimeDigitized
+     * \return The date and time when the image was stored as digital data.
+     */
+    QDateTime dateTimeDigitized() const;
+    void setDateTimeDigitized(const QDateTime& dt);
+
     /*!
      * \brief title
      * \return The title of the image.
@@ -239,17 +253,58 @@ public:
 
     /*!
      * \brief toByteArray
+     * Converts the class to RAW data. The raw data contains:
+     * - TIFF header
+     * - MAIN IFD
+     * - EXIF IFD
+     * - GPS IFD
      * \param byteOrder Sets the serialization byte order for EXIF data.
      * \return A byte array containing the serialized data.
+     * \sa write
      */
     QByteArray toByteArray(const QDataStream::ByteOrder &byteOrder = EXIF_DEFAULT_BYTEORDER) const;
 
+    /*!
+     * \brief exifIfdByteArray
+     * Convert the EXIF IFD only to RAW data. Useful when you want to add EXIF data to an existing TIFF container.
+     * \param byteOrder Sets the serialization byte order for the data.
+     * \return A byte array containing the serialized data.
+     */
+    QByteArray exifIfdByteArray(const QDataStream::ByteOrder &byteOrder = EXIF_DEFAULT_BYTEORDER) const;
+    /*!
+     * \brief setExifIfdByteArray
+     * \param ba The RAW data of EXIF IFD.
+     * \param byteOrder Sets the serialization byte order of the data.
+     * \return True on success, otherwise false.
+     */
+    bool setExifIfdByteArray(const QByteArray& ba, const QDataStream::ByteOrder &byteOrder = EXIF_DEFAULT_BYTEORDER);
+
+    /*!
+     * \brief gpsIfdByteArray
+     * Convert the GPS IFD only to RAW data. Useful when you want to add GPS data to an existing TIFF container.
+     * \param byteOrder Sets the serialization byte order for the data.
+     * \return A byte array containing the serialized data.
+     */
+    QByteArray gpsIfdByteArray(const QDataStream::ByteOrder &byteOrder = EXIF_DEFAULT_BYTEORDER) const;
+    /*!
+     * \brief setGpsIfdByteArray
+     * \param ba The RAW data of GPS IFD.
+     * \param byteOrder Sets the serialization byte order of the data.
+     * \return True on success, otherwise false.
+     */
+    bool setGpsIfdByteArray(const QByteArray& ba, const QDataStream::ByteOrder &byteOrder = EXIF_DEFAULT_BYTEORDER);
+
     /*!
      * \brief write
-     * Serialize the class on a device.
+     * Serialize the class on a device. The serialized data contains:
+     * - TIFF header
+     * - MAIN IFD
+     * - EXIF IFD
+     * - GPS IFD
      * \param device A random access device.
      * \param byteOrder Sets the serialization byte order for EXIF data.
      * \return True on success, otherwise false.
+     * \sa toByteArray
      */
     bool write(QIODevice *device, const QDataStream::ByteOrder &byteOrder = EXIF_DEFAULT_BYTEORDER) const;
 

src/imageformats/util_p.h

@@ -24,6 +24,7 @@
 #define META_KEY_HOSTCOMPUTER "HostComputer"
 #define META_KEY_LATITUDE "Latitude"
 #define META_KEY_LONGITUDE "Longitude"
+#define META_KEY_MODIFICATIONDATE "ModificationDate"
 #define META_KEY_OWNER "Owner"
 #define META_KEY_SOFTWARE "Software"
 #define META_KEY_TITLE "Title"