PSD: improved option support

Added support for the following options:
- `ImageTransformation`: uses EXIF data (same behaviour of Photoshop and GIMP)
- `Description`: uses EXIF data
- `ImageFormat` 

Closes #17

autotests/read/psd/orientation1.psd.json

@@ -0,0 +1,11 @@
+[
+    {
+        "fileName" : "orientation_all.png",
+        "metadata" : [
+            {
+                "key" : "Software" ,
+                "value" : "LIFE Pro 2.18.5 (Windows)"
+            }
+        ]
+    }
+]

autotests/read/psd/orientation2.psd.json

@@ -0,0 +1,11 @@
+[
+    {
+        "fileName" : "orientation_all.png",
+        "metadata" : [
+            {
+                "key" : "Software" ,
+                "value" : "LIFE Pro 2.18.5 (Windows)"
+            }
+        ]
+    }
+]

autotests/read/psd/orientation3.psd.json

@@ -0,0 +1,11 @@
+[
+    {
+        "fileName" : "orientation_all.png",
+        "metadata" : [
+            {
+                "key" : "Software" ,
+                "value" : "LIFE Pro 2.18.5 (Windows)"
+            }
+        ]
+    }
+]

autotests/read/psd/orientation4.psd.json

@@ -0,0 +1,11 @@
+[
+    {
+        "fileName" : "orientation_all.png",
+        "metadata" : [
+            {
+                "key" : "Software" ,
+                "value" : "LIFE Pro 2.18.5 (Windows)"
+            }
+        ]
+    }
+]

autotests/read/psd/orientation5.psd.json

@@ -0,0 +1,11 @@
+[
+    {
+        "fileName" : "orientation_all.png",
+        "metadata" : [
+            {
+                "key" : "Software" ,
+                "value" : "LIFE Pro 2.18.5 (Windows)"
+            }
+        ]
+    }
+]

autotests/read/psd/orientation6.psd.json

@@ -0,0 +1,11 @@
+[
+    {
+        "fileName" : "orientation_all.png",
+        "metadata" : [
+            {
+                "key" : "Software" ,
+                "value" : "LIFE Pro 2.18.5 (Windows)"
+            }
+        ]
+    }
+]

autotests/read/psd/orientation7.psd.json

@@ -0,0 +1,11 @@
+[
+    {
+        "fileName" : "orientation_all.png",
+        "metadata" : [
+            {
+                "key" : "Software" ,
+                "value" : "LIFE Pro 2.18.5 (Windows)"
+            }
+        ]
+    }
+]

autotests/read/psd/orientation8.psd.json

@@ -0,0 +1,11 @@
+[
+    {
+        "fileName" : "orientation_all.png",
+        "metadata" : [
+            {
+                "key" : "Software" ,
+                "value" : "LIFE Pro 2.18.5 (Windows)"
+            }
+        ]
+    }
+]

src/imageformats/psd.cpp

@@ -529,15 +529,11 @@ static bool setXmpData(QImage& img, const PSDImageResourceSection& irs)
  * \brief setExifData
  * Adds EXIF metadata to QImage.
  * \param img The image.
- * \param irs The image resource section.
+ * \param exif The decoded EXIF data.
  * \return True on success, otherwise false.
  */
-static bool setExifData(QImage& img, const PSDImageResourceSection& irs)
+static bool setExifData(QImage &img, const MicroExif &exif)
 {
-    if (!irs.contains(IRI_EXIFDATA1))
-        return false;
-    auto irb = irs.value(IRI_EXIFDATA1);
-    auto exif = MicroExif::fromByteArray(irb.data);
     if (exif.isEmpty())
         return false;
     exif.toImageMetadata(img);
@@ -545,12 +541,12 @@ static bool setExifData(QImage& img, const PSDImageResourceSection& irs)
 }
 
 /*!
- * \brief hasMergedData
+ * \brief HasMergedData
  * Checks if merged image data are available.
  * \param irs The image resource section.
  * \return True on success or if the block does not exist, otherwise false.
  */
-static bool hasMergedData(const PSDImageResourceSection& irs)
+static bool HasMergedData(const PSDImageResourceSection &irs)
 {
     if (!irs.contains(IRI_VERSIONINFO))
         return true;
@@ -1107,39 +1103,161 @@ bool readChannel(QByteArray& target, QDataStream &stream, quint32 compressedSize
     return stream.status() == QDataStream::Ok;
 }
 
-// Load the PSD image.
+} // Private
-static bool LoadPSD(QDataStream &stream, const PSDHeader &header, QImage &img)
+
+class PSDHandlerPrivate
+{
+public:
+    PSDHandlerPrivate()
+    {
+    }
+    ~PSDHandlerPrivate()
+    {
+    }
+
+    bool isPsb() const
+    {
+        return m_header.version == 2;
+    }
+
+    bool isValid() const
+    {
+        return IsValid(m_header);
+    }
+
+    bool isSupported() const
+    {
+        return IsSupported(m_header);
+    }
+
+    bool hasAlpha() const
+    {
+        // Try to identify the nature of spots: note that this is just one of many ways to identify the presence
+        // of alpha channels: should work in most cases where colorspaces != RGB/Gray
+        auto alpha = m_header.color_mode == CM_RGB;
+        if (!m_lms.isNull())
+            alpha = m_lms.hasAlpha();
+        return alpha;
+    }
+
+    bool hasMergedData() const
+    {
+        return HasMergedData(m_irs);
+    }
+
+    QSize size() const
+    {
+        if (isValid())
+            return QSize(m_header.width, m_header.height);
+        return {};
+    }
+
+    QImage::Format format() const
+    {
+        return imageFormat(m_header, hasAlpha());
+    }
+
+    QImageIOHandler::Transformations transformation() const
+    {
+        return m_exif.transformation();
+    }
+
+    bool readInfo(QDataStream &stream)
     {
         // Checking for PSB
-    auto isPsb = header.version == 2;
+        auto ok = false;
-    bool ok = false;
+
+        // Header
+        stream >> m_header;
+
+        // Check image file format.
+        if (stream.atEnd() || !IsValid(m_header)) {
+            // qDebug() << "This PSD file is not valid.";
+            return false;
+        }
+
+        // Check if it's a supported format.
+        if (!IsSupported(m_header)) {
+            // qDebug() << "This PSD file is not supported.";
+            return false;
+        }
 
         // Color Mode Data section
-    auto cmds = readColorModeDataSection(stream, &ok);
+        m_cmds = readColorModeDataSection(stream, &ok);
         if (!ok) {
             qDebug() << "Error while skipping Color Mode Data section";
             return false;
         }
 
         // Image Resources Section
-    auto irs = readImageResourceSection(stream, &ok);
+        m_irs = readImageResourceSection(stream, &ok);
         if (!ok) {
             qDebug() << "Error while reading Image Resources Section";
             return false;
         }
         // Checking for merged image (Photoshop compatibility data)
-    if (!hasMergedData(irs)) {
+        if (!hasMergedData()) {
             qDebug() << "No merged data found";
             return false;
         }
 
         // Layer and Mask section
-    auto lms = readLayerAndMaskSection(stream, isPsb, &ok);
+        m_lms = readLayerAndMaskSection(stream, isPsb(), &ok);
         if (!ok) {
             qDebug() << "Error while skipping Layer and Mask section";
             return false;
         }
 
+        // storing decoded EXIF
+        if (m_irs.contains(IRI_EXIFDATA1)) {
+            m_exif = MicroExif::fromByteArray(m_irs.value(IRI_EXIFDATA1).data);
+        }
+
+        return ok;
+    }
+
+    PSDHeader m_header;
+    PSDColorModeDataSection m_cmds;
+    PSDImageResourceSection m_irs;
+    PSDLayerAndMaskSection m_lms;
+
+    // cache to avoid decoding exif multiple times
+    MicroExif m_exif;
+};
+
+PSDHandler::PSDHandler()
+    : QImageIOHandler()
+    , d(new PSDHandlerPrivate)
+{
+}
+
+bool PSDHandler::canRead() const
+{
+    if (canRead(device())) {
+        setFormat("psd");
+        return true;
+    }
+    return false;
+}
+
+bool PSDHandler::read(QImage *image)
+{
+    QDataStream stream(device());
+    stream.setByteOrder(QDataStream::BigEndian);
+
+    if (!d->isValid()) {
+        if (!d->readInfo(stream))
+            return false;
+    }
+
+    auto &&header = d->m_header;
+    auto &&cmds = d->m_cmds;
+    auto &&irs = d->m_irs;
+    // auto &&lms = d->m_lms;
+    auto isPsb = d->isPsb();
+    auto alpha = d->hasAlpha();
+
+    QImage img;
     // Find out if the data is compressed.
     // Known values:
     //   0: no compression
@@ -1151,19 +1269,13 @@ static bool LoadPSD(QDataStream &stream, const PSDHeader &header, QImage &img)
         return false;
     }
 
-    // Try to identify the nature of spots: note that this is just one of many ways to identify the presence
+    const QImage::Format format = d->format();
-    // of alpha channels: should work in most cases where colorspaces != RGB/Gray
-    auto alpha = header.color_mode == CM_RGB;
-    if (!lms.isNull())
-        alpha = lms.hasAlpha();
-
-    const QImage::Format format = imageFormat(header, alpha);
     if (format == QImage::Format_Invalid) {
         qWarning() << "Unsupported image format. color_mode:" << header.color_mode << "depth:" << header.depth << "channel_count:" << header.channel_count;
         return false;
     }
 
-    img = imageAlloc(header.width, header.height, format);
+    img = imageAlloc(d->size(), format);
     if (img.isNull()) {
         qWarning() << "Failed to allocate image, invalid dimensions?" << QSize(header.width, header.height);
         return false;
@@ -1379,7 +1491,7 @@ static bool LoadPSD(QDataStream &stream, const PSDHeader &header, QImage &img)
     }
 
     // EXIF data
-    if (!setExifData(img, irs)) {
+    if (!setExifData(img, d->m_exif)) {
         // qDebug() << "No EXIF data found!";
     }
 
@@ -1390,60 +1502,6 @@ static bool LoadPSD(QDataStream &stream, const PSDHeader &header, QImage &img)
         img.setText(QStringLiteral("PSDDuotoneOptions"), QString::fromUtf8(cmds.duotone.data.toHex()));
     }
 
-    return true;
-}
-
-} // Private
-
-class PSDHandlerPrivate
-{
-public:
-    PSDHandlerPrivate() {}
-    ~PSDHandlerPrivate() {}
-    PSDHeader m_header;
-};
-
-PSDHandler::PSDHandler()
-    : QImageIOHandler()
-    , d(new PSDHandlerPrivate)
-{
-}
-
-bool PSDHandler::canRead() const
-{
-    if (canRead(device())) {
-        setFormat("psd");
-        return true;
-    }
-    return false;
-}
-
-bool PSDHandler::read(QImage *image)
-{
-    QDataStream s(device());
-    s.setByteOrder(QDataStream::BigEndian);
-
-    auto&& header = d->m_header;
-    s >> header;
-
-    // Check image file format.
-    if (s.atEnd() || !IsValid(header)) {
-        // qDebug() << "This PSD file is not valid.";
-        return false;
-    }
-
-    // Check if it's a supported format.
-    if (!IsSupported(header)) {
-        // qDebug() << "This PSD file is not supported.";
-        return false;
-    }
-
-    QImage img;
-    if (!LoadPSD(s, header, img)) {
-        // qDebug() << "Error loading PSD file.";
-        return false;
-    }
-
     *image = img;
     return true;
 }
@@ -1452,6 +1510,12 @@ bool PSDHandler::supportsOption(ImageOption option) const
 {
     if (option == QImageIOHandler::Size)
         return true;
+    if (option == QImageIOHandler::ImageFormat)
+        return true;
+    if (option == QImageIOHandler::ImageTransformation)
+        return true;
+    if (option == QImageIOHandler::Description)
+        return true;
     return false;
 }
 
@@ -1459,18 +1523,37 @@ QVariant PSDHandler::option(ImageOption option) const
 {
     QVariant v;
 
-    if (option == QImageIOHandler::Size) {
+    if (auto dev = device()) {
-        auto&& header = d->m_header;
+        if (!d->isValid()) {
-        if (IsValid(header)) {
+            QDataStream s(dev);
-            v = QVariant::fromValue(QSize(header.width, header.height));
-        } else if (auto dev = device()) {
-            auto ba = dev->peek(sizeof(PSDHeader));
-            QDataStream s(ba);
             s.setByteOrder(QDataStream::BigEndian);
+            d->readInfo(s);
+        }
+    }
 
-            s >> header;
+    if (option == QImageIOHandler::Size) {
-            if (s.status() == QDataStream::Ok && IsValid(header))
+        if (d->isValid()) {
-                v = QVariant::fromValue(QSize(header.width, header.height));
+            v = QVariant::fromValue(d->size());
+        }
+    }
+
+    if (option == QImageIOHandler::ImageFormat) {
+        if (d->isValid()) {
+            v = QVariant::fromValue(d->format());
+        }
+    }
+
+    if (option == QImageIOHandler::ImageTransformation) {
+        if (d->isValid()) {
+            v = QVariant::fromValue(int(d->transformation()));
+        }
+    }
+
+    if (option == QImageIOHandler::Description) {
+        if (d->isValid()) {
+            auto descr = d->m_exif.description();
+            if (!descr.isEmpty())
+                v = QVariant::fromValue(descr);
         }
     }