JXL: Resolution and metadata support via EXIF

- Added a class to read and write minimal exif metadata.
- JXL plugin uses EXIF metadata to load/save the resolution of the image (like GIMP).
- JXL plugin uses EXIF metadata to set/store text metadata and date/time.
- Enable info display in Dolphin (JXL File -> Properties -> Details on a JXL file, see image below).
- Enabled read test to check also image metadata and resolution.

![_52C044E4-1BA9-4D84-AC0A-B834CDAF72D8_](/uploads/f1649c2b506bf61a5f5488da0d4a4534/_52C044E4-1BA9-4D84-AC0A-B834CDAF72D8_.png){width=401 height=357}

autotests/CMakeLists.txt

@@ -19,9 +19,15 @@ macro(kimageformats_read_tests)
     endif()
 
     foreach(_testname ${KIF_RT_UNPARSED_ARGUMENTS})
+        string(REGEX MATCH "-skipoptional" _is_skip_optional "${_testname}")
+        unset(skip_optional_arg)
+        if (_is_skip_optional)
+            set(skip_optional_arg "--skip-optional-tests")
+            string(REGEX REPLACE "-skipoptional$" "" _testname "${_testname}")
+        endif()
         add_test(
             NAME kimageformats-read-${_testname}
-            COMMAND readtest ${_fuzzarg} ${_testname}
+            COMMAND readtest ${skip_optional_arg} ${_fuzzarg} ${_testname}
         )
     endforeach(_testname)
 endmacro()
@@ -132,9 +138,15 @@ if (OpenJPEG_FOUND)
 endif()
 
 if (LibJXL_FOUND AND LibJXLThreads_FOUND)
-    kimageformats_read_tests(
-        jxl
-    )
+    if(LibJXL_VERSION VERSION_GREATER_EQUAL "0.11.0")
+        kimageformats_read_tests(
+            jxl
+        )
+    else()
+        kimageformats_read_tests(
+            jxl-skipoptional
+        )
+    endif()
     kimageformats_write_tests(
         jxl-nodatacheck-lossless
     )

autotests/read/jxl/gimp_exif.jxl.json

@@ -0,0 +1,19 @@
+[
+    {
+        "fileName" : "gimp_exif.png",
+        "metadata" : [
+            {
+                "Key" : "CreationDate",
+                "Value" : "2025-01-05T10:18:16"
+            },
+            {
+                "Key" : "Software" ,
+                "Value" : "GIMP 3.0.0-RC2"
+            }
+        ],
+        "resolution" : {
+            "dotsPerMeterX" : 5905,
+            "dotsPerMeterY" : 6692
+        }
+    }
+]

autotests/readtest.cpp

@@ -198,7 +198,7 @@ int main(int argc, char **argv)
     QCoreApplication::removeLibraryPath(QStringLiteral(PLUGIN_DIR));
     QCoreApplication::addLibraryPath(QStringLiteral(PLUGIN_DIR));
     QCoreApplication::setApplicationName(QStringLiteral("readtest"));
-    QCoreApplication::setApplicationVersion(QStringLiteral("1.2.0"));
+    QCoreApplication::setApplicationVersion(QStringLiteral("1.3.0"));
 
     QCommandLineParser parser;
     parser.setApplicationDescription(QStringLiteral("Performs basic image conversion checking."));
@@ -208,8 +208,11 @@ int main(int argc, char **argv)
     QCommandLineOption fuzz(QStringList() << QStringLiteral("f") << QStringLiteral("fuzz"),
                             QStringLiteral("Allow for some deviation in ARGB data."),
                             QStringLiteral("max"));
-    parser.addOption(fuzz);
+    QCommandLineOption skipOptTest({QStringLiteral("skip-optional-tests")},
+                                   QStringLiteral("Skip optional data tests (metadata, resolution, etc.)."));
 
+    parser.addOption(fuzz);
+    parser.addOption(skipOptTest);
     parser.process(app);
 
     const QStringList args = parser.positionalArguments();
@@ -314,6 +317,7 @@ int main(int argc, char **argv)
                 continue;
             }
 
+            // option test
             OptionTest optionTest;
             if (!optionTest.store(&inputReader)) {
                 QTextStream(stdout) << "FAIL : " << fi.fileName() << ": error while reading options\n";
@@ -339,6 +343,17 @@ int main(int argc, char **argv)
                 continue;
             }
 
+            // metadata checks
+            if (!parser.isSet(skipOptTest)) {
+                QString optError;
+                if (!timg.checkOptionaInfo(inputImage, optError)) {
+                    QTextStream(stdout) << "FAIL : " << fi.fileName() << " : " << optError << "\n";
+                    ++failed;
+                    continue;
+                }
+            }
+
+            // image compare
             if (expImage.width() != inputImage.width()) {
                 QTextStream(stdout) << "FAIL : " << fi.fileName() << ": width was " << inputImage.width() << " but " << expfilename << " width was "
                                     << expImage.width() << "\n";

autotests/templateimage.cpp

@@ -12,6 +12,49 @@
 #include <QJsonObject>
 #include <QVersionNumber>
 
+static QJsonObject searchObject(const QFileInfo& file)
+{
+    auto fi = QFileInfo(QStringLiteral("%1.json").arg(file.filePath()));
+    if (!fi.exists()) {
+        return {};
+    }
+
+    QFile f(fi.filePath());
+    if (!f.open(QFile::ReadOnly)) {
+        return {};
+    }
+
+    QJsonParseError err;
+    auto doc = QJsonDocument::fromJson(f.readAll(), &err);
+    if (err.error != QJsonParseError::NoError || !doc.isArray()) {
+        return {};
+    }
+
+    auto currentQt = QVersionNumber::fromString(qVersion());
+    auto arr = doc.array();
+    for (auto val : arr) {
+        if (!val.isObject())
+            continue;
+        auto obj = val.toObject();
+        auto minQt = QVersionNumber::fromString(obj.value("minQtVersion").toString());
+        auto maxQt = QVersionNumber::fromString(obj.value("maxQtVersion").toString());
+        auto name = obj.value("fileName").toString();
+        auto unsupportedFormat = obj.value("unsupportedFormat").toBool();
+
+        // filter
+        if (name.isEmpty() && !unsupportedFormat)
+            continue;
+        if (!minQt.isNull() && currentQt < minQt)
+            continue;
+        if (!maxQt.isNull() && currentQt > maxQt)
+            continue;
+        return obj;
+    }
+
+    return {};
+}
+
+
 TemplateImage::TemplateImage(const QFileInfo &fi) :
     m_fi(fi)
 {
@@ -45,6 +88,43 @@ QFileInfo TemplateImage::compareImage(TestFlags &flags, QString& comment) const
     return legacyImage();
 }
 
+bool TemplateImage::checkOptionaInfo(const QImage& image, QString& error) const
+{
+    auto obj = searchObject(m_fi);
+    if (obj.isEmpty()) {
+        return true;
+    }
+
+    // Test resolution
+    auto res = obj.value("resolution").toObject();
+    if (!res.isEmpty()) {
+        auto resx = res.value("dotsPerMeterX").toInt();
+        auto resy = res.value("dotsPerMeterY").toInt();
+        if (resx != image.dotsPerMeterX()) {
+            error = QStringLiteral("X resolution mismatch (current: %1, expected: %2)!").arg(image.dotsPerMeterX()).arg(resx);
+            return false;
+        }
+        if (resy != image.dotsPerMeterY()) {
+            error = QStringLiteral("Y resolution mismatch (current: %1, expected: %2)!").arg(image.dotsPerMeterY()).arg(resy);
+            return false;
+        }
+    }
+
+    // Test metadata
+    auto meta = obj.value("metadata").toArray();
+    for (auto jv : meta) {
+        auto obj = jv.toObject();
+        auto key = obj.value("Key").toString();
+        auto val = obj.value("Value").toString();
+        auto cur = image.text(key);
+        if (cur != val) {
+            error = QStringLiteral("Metadata '%1' mismatch (current: '%2', expected:'%3')!").arg(key, cur, val);
+            return false;
+        }
+    }
+
+    return true;
+}
 
 QStringList TemplateImage::suffixes()
 {
@@ -66,51 +146,25 @@ QFileInfo TemplateImage::legacyImage() const
 QFileInfo TemplateImage::jsonImage(TestFlags &flags, QString& comment) const
 {
     flags = TestFlag::None;
-    auto fi = QFileInfo(QStringLiteral("%1.json").arg(m_fi.filePath()));
-    if (!fi.exists()) {
+
+    auto obj = searchObject(m_fi);
+    if (obj.isEmpty()) {
         return {};
     }
 
-    QFile f(fi.filePath());
-    if (!f.open(QFile::ReadOnly)) {
+    auto name = obj.value("fileName").toString();
+    auto unsupportedFormat = obj.value("unsupportedFormat").toBool();
+    comment = obj.value("comment").toString();
+
+    if(obj.value("disableAutoTransform").toBool()) {
+        flags |= TestFlag::DisableAutotransform;
+    }
+
+    if (unsupportedFormat) {
+        flags |= TestFlag::SkipTest;
         return {};
     }
 
-    QJsonParseError err;
-    auto doc = QJsonDocument::fromJson(f.readAll(), &err);
-    if (err.error != QJsonParseError::NoError || !doc.isArray()) {
-        return {};
-    }
-
-    auto currentQt = QVersionNumber::fromString(qVersion());
-    auto arr = doc.array();
-    for (auto val : arr) {
-        if (!val.isObject())
-            continue;
-        auto obj = val.toObject();
-        auto minQt = QVersionNumber::fromString(obj.value("minQtVersion").toString());
-        auto maxQt = QVersionNumber::fromString(obj.value("maxQtVersion").toString());
-        auto name = obj.value("fileName").toString();
-        auto unsupportedFormat = obj.value("unsupportedFormat").toBool();
-        comment = obj.value("comment").toString();
-
-        if(obj.value("disableAutoTransform").toBool())
-            flags |= TestFlag::DisableAutotransform;
-
-        // filter
-        if (name.isEmpty() && !unsupportedFormat)
-            continue;
-        if (!minQt.isNull() && currentQt < minQt)
-            continue;
-        if (!maxQt.isNull() && currentQt > maxQt)
-            continue;
-        if (unsupportedFormat) {
-            flags |= TestFlag::SkipTest;
-            break;
-        }
-        return QFileInfo(QStringLiteral("%1/%2").arg(fi.path(), name));
-    }
-
-    return {};
+    return QFileInfo(QStringLiteral("%1/%2").arg(m_fi.path(), name));
 }
 

autotests/templateimage.h

@@ -8,6 +8,7 @@
 #define TEMPLATEIMAGE_H
 
 #include <QFileInfo>
+#include <QImage>
 
 /*!
  * \brief The TemplateImage class
@@ -60,6 +61,15 @@ public:
      */
     QFileInfo compareImage(TestFlags &flags, QString& comment) const;
 
+    /*!
+     * \brief checkOptionaInfo
+     * Verify the optional information (resolution, metadata, etc.) of the image with that in the template if present.
+     * \param image The image to check optional information on.
+     * \param error The error message when returns false.
+     * \return True on success, otherwise false.
+     */
+    bool checkOptionaInfo(const QImage& image, QString& error) const;
+
     /*!
      * \brief suffixes
      * \return The list of suffixes considered templates.