PSD: support native CMYK introduced by Qt 6.8

Qt 6.8 will introduce native support for the CMYK (8-bit) format.
With this patch you will finally be able to correctly see the colors of CMYK images with ICC profile.
The testing part has been updated with the addition of an (optional) json file for each image to test. Inside you enter which image to use depending on the Qt version.

In short:
- Added native CMYK suport to PSD reader
- CMYK with alpha is converted using QColorSpace in a RGBA image
- Read tests changed to use the correct comparison image based on the Qt version
- Fixed also XCF tests: now works with all Qt version (see also [QTBUG-120614](https://bugreports.qt.io/browse/QTBUG-120614))
- Work around for CCBUG: 468288

autotests/CMakeLists.txt

@@ -11,7 +11,7 @@ macro(kimageformats_read_tests)
     endif()
 
     if (NOT TARGET readtest)
-        add_executable(readtest readtest.cpp)
+        add_executable(readtest readtest.cpp templateimage.cpp)
         target_link_libraries(readtest Qt6::Gui)
         target_compile_definitions(readtest
             PRIVATE IMAGEDIR="${CMAKE_CURRENT_SOURCE_DIR}/read")

autotests/read/psd/cmyk16_testcard.psd.json

@@ -0,0 +1,11 @@
+[
+    {
+        "minQtVersion" : "6.8.0",
+        "fileName" : "cmyk16_testcard_qt6_8.tif"
+    },
+    {
+        "minQtVersion" : "6.0.0",
+        "maxQtVersion" : "6.7.99",
+        "fileName" : "cmyk16_testcard.png"
+    }
+]

autotests/read/psd/cmyk8_testcard.psd.json

@@ -0,0 +1,11 @@
+[
+    {
+        "minQtVersion" : "6.8.0",
+        "fileName" : "cmyk8_testcard_qt6_8.tif"
+    },
+    {
+        "minQtVersion" : "6.0.0",
+        "maxQtVersion" : "6.7.99",
+        "fileName" : "cmyk8_testcard.png"
+    }
+]

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

@@ -0,0 +1,11 @@
+[
+    {
+        "minQtVersion" : "6.8.0",
+        "fileName" : "cmyka-16bits_qt6_8.png"
+    },
+    {
+        "minQtVersion" : "6.0.0",
+        "maxQtVersion" : "6.7.99",
+        "fileName" : "cmyka-16bits.png"
+    }
+]

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

@@ -0,0 +1,11 @@
+[
+    {
+        "minQtVersion" : "6.8.0",
+        "fileName" : "cmyka-8bits_qt6_8.png"
+    },
+    {
+        "minQtVersion" : "6.0.0",
+        "maxQtVersion" : "6.7.99",
+        "fileName" : "cmyka-8bits.png"
+    }
+]

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

@@ -0,0 +1,11 @@
+[
+    {
+        "minQtVersion" : "6.8.0",
+        "fileName" : "mch-16bits_qt_6_8.tif"
+    },
+    {
+        "minQtVersion" : "6.0.0",
+        "maxQtVersion" : "6.7.99",
+        "fileName" : "mch-16bits.png"
+    }
+]

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

@@ -0,0 +1,11 @@
+[
+    {
+        "minQtVersion" : "6.8.0",
+        "fileName" : "mch-8bits_qt_6.8.tif"
+    },
+    {
+        "minQtVersion" : "6.0.0",
+        "maxQtVersion" : "6.7.99",
+        "fileName" : "mch-8bits.png"
+    }
+]

autotests/read/xcf/birthday16.xcf.json

@@ -0,0 +1,32 @@
+[
+    {
+        "minQtVersion" : "6.7.0",
+        "fileName" : "birthday16.png",
+        "seeAlso" : "https://bugreports.qt.io/browse/QTBUG-120614"
+    },
+    {
+        "minQtVersion" : "6.0.0",
+        "maxQtVersion" : "6.2.10",
+        "fileName" : "birthday16_alphabug.png"
+    },
+    {
+        "minQtVersion" : "6.3.0",
+        "maxQtVersion" : "6.3.2",
+        "fileName" : "birthday32_alphabug.png"
+    },
+    {
+        "minQtVersion" : "6.4.0",
+        "maxQtVersion" : "6.4.3",
+        "fileName" : "birthday32_alphabug.png"
+    },
+    {
+        "minQtVersion" : "6.5.0",
+        "maxQtVersion" : "6.5.4",
+        "fileName" : "birthday16_alphabug.png"
+    },
+    {
+        "minQtVersion" : "6.6.0",
+        "maxQtVersion" : "6.6.1",
+        "fileName" : "birthday16_alphabug.png"
+    }
+]

autotests/read/xcf/birthday32.xcf.json

@@ -0,0 +1,32 @@
+[
+    {
+        "minQtVersion" : "6.7.0",
+        "fileName" : "birthday32.png",
+        "seeAlso" : "https://bugreports.qt.io/browse/QTBUG-120614"
+    },
+    {
+        "minQtVersion" : "6.0.0",
+        "maxQtVersion" : "6.2.10",
+        "fileName" : "birthday32_alphabug.png"
+    },
+    {
+        "minQtVersion" : "6.3.0",
+        "maxQtVersion" : "6.3.2",
+        "fileName" : "birthday32_alphabug.png"
+    },
+    {
+        "minQtVersion" : "6.4.0",
+        "maxQtVersion" : "6.4.3",
+        "fileName" : "birthday32_alphabug.png"
+    },
+    {
+        "minQtVersion" : "6.5.0",
+        "maxQtVersion" : "6.5.4",
+        "fileName" : "birthday32_alphabug.png"
+    },
+    {
+        "minQtVersion" : "6.6.0",
+        "maxQtVersion" : "6.6.1",
+        "fileName" : "birthday32_alphabug.png"
+    }
+]

autotests/readtest.cpp

@@ -16,6 +16,7 @@
 #include <QTextStream>
 
 #include "../tests/format-enum.h"
+#include "templateimage.h"
 
 #include "fuzzyeq.cpp"
 
@@ -95,7 +96,7 @@ int main(int argc, char **argv)
     QCoreApplication::removeLibraryPath(QStringLiteral(PLUGIN_DIR));
     QCoreApplication::addLibraryPath(QStringLiteral(PLUGIN_DIR));
     QCoreApplication::setApplicationName(QStringLiteral("readtest"));
-    QCoreApplication::setApplicationVersion(QStringLiteral("1.1.0"));
+    QCoreApplication::setApplicationVersion(QStringLiteral("1.2.0"));
 
     QCommandLineParser parser;
     parser.setApplicationDescription(QStringLiteral("Performs basic image conversion checking."));
@@ -159,22 +160,24 @@ int main(int argc, char **argv)
             QTextStream(stdout) << "* Run on RANDOM ACCESS device\n";
         }
         for (const QFileInfo &fi : lstImgDir) {
-            if (!fi.suffix().compare("png", Qt::CaseInsensitive) || !fi.suffix().compare("tif", Qt::CaseInsensitive)) {
+            TemplateImage timg(fi);
+            if (timg.isTemplate()) {
                 continue;
             }
-            int suffixPos = fi.filePath().size() - suffix.size();
-            QString inputfile = fi.filePath();
-            QString fmt = QStringLiteral("png");
-            QString expfile = fi.filePath().replace(suffixPos, suffix.size(), fmt);
-            if (!QFile::exists(expfile)) { // try with tiff
-                fmt = QStringLiteral("tif");
-                expfile = fi.filePath().replace(suffixPos, suffix.size(), fmt);
-            }
-            QString expfilename = QFileInfo(expfile).fileName();
 
-            std::unique_ptr<QIODevice> inputDevice(seq ? new SequentialFile(inputfile) : new QFile(inputfile));
+            QFileInfo expFileInfo = timg.compareImage();
+            if (!formatStrings.contains(expFileInfo.suffix(), Qt::CaseInsensitive)) {
+                // Work Around for CCBUG: 468288
+                QTextStream(stdout) << "SKIP : " << fi.fileName() << ": comparison image " << expFileInfo.fileName() << " cannot be loaded due to the lack of "
+                                    << expFileInfo.suffix().toUpper() << " plugin!\n";
+                ++skipped;
+                continue;
+            }
+            QString expfilename = expFileInfo.fileName();
+
+            std::unique_ptr<QIODevice> inputDevice(seq ? new SequentialFile(fi.filePath()) : new QFile(fi.filePath()));
             QImageReader inputReader(inputDevice.get(), format);
-            QImageReader expReader(expfile, fmt.toLatin1());
+            QImageReader expReader(expFileInfo.filePath());
 
             QImage inputImage;
             QImage expImage;

autotests/templateimage.cpp

@@ -0,0 +1,98 @@
+/*
+    SPDX-FileCopyrightText: 2024 Mirco Miranda <mircomir@outlook.com>
+
+    SPDX-License-Identifier: LGPL-2.1-only OR LGPL-3.0-only OR LicenseRef-KDE-Accepted-LGPL
+*/
+
+#include "templateimage.h"
+
+#include <QFile>
+#include <QJsonArray>
+#include <QJsonDocument>
+#include <QJsonObject>
+#include <QVersionNumber>
+
+TemplateImage::TemplateImage(const QFileInfo &fi) :
+    m_fi(fi)
+{
+
+}
+
+bool TemplateImage::isTemplate() const
+{
+    auto list = suffixes();
+    for (auto&& suffix : list) {
+        if (!m_fi.suffix().compare(suffix, Qt::CaseInsensitive))
+            return true;
+    }
+    return false;
+}
+
+QFileInfo TemplateImage::compareImage() const
+{
+    auto fi = jsonImage();
+    if (fi.exists()) {
+        return fi;
+    }
+    return legacyImage();
+}
+
+
+QStringList TemplateImage::suffixes()
+{
+    return QStringList({"png", "tif", "tiff", "json"});
+}
+
+QFileInfo TemplateImage::legacyImage() const
+{
+    auto list = suffixes();
+    for (auto&& suffix : list) {
+        auto fi = QFileInfo(QStringLiteral("%1/%2.%3").arg(m_fi.path(), m_fi.completeBaseName(), suffix));
+        if (fi.exists()) {
+            return fi;
+        }
+    }
+    return {};
+}
+
+QFileInfo TemplateImage::jsonImage() const
+{
+    auto fi = QFileInfo(QStringLiteral("%1.json").arg(m_fi.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();
+
+        // filter
+        if (name.isEmpty())
+            continue;
+        if (!minQt.isNull() && currentQt < minQt)
+            continue;
+        if (!maxQt.isNull() && currentQt > maxQt)
+            continue;
+        return QFileInfo(QStringLiteral("%1/%2").arg(fi.path(), name));
+    }
+
+    return {};
+}
+

autotests/templateimage.h

@@ -0,0 +1,72 @@
+/*
+    SPDX-FileCopyrightText: 2024 Mirco Miranda <mircomir@outlook.com>
+
+    SPDX-License-Identifier: LGPL-2.1-only OR LGPL-3.0-only OR LicenseRef-KDE-Accepted-LGPL
+*/
+
+#ifndef TEMPLATEIMAGE_H
+#define TEMPLATEIMAGE_H
+
+#include <QFileInfo>
+
+/*!
+ * \brief The TemplateImage class
+ * Given an image name, it decides the template image to compare it with.
+ */
+class TemplateImage
+{
+public:
+    /*!
+     * \brief TemplateImage
+     * \param fi The image to test.
+     */
+    TemplateImage(const QFileInfo& fi);
+
+    /*!
+     * \brief TemplateImage
+     * Default copy constructor.
+     */
+    TemplateImage(const TemplateImage& other) = default;
+    /*!
+     * \brief operator =
+     * Default copy operator
+     */
+    TemplateImage& operator=(const TemplateImage& other) = default;
+
+    /*!
+     * \brief isTemplate
+     * \return True if the image is a template, false otherwise.
+     * \sa suffixes
+     */
+    bool isTemplate() const;
+
+    /*!
+     * \brief compareImage
+     * \return The template image to use for the comparison.
+     */
+    QFileInfo compareImage() const;
+
+    /*!
+     * \brief suffixes
+     * \return The list of suffixes considered templates.
+     */
+    static QStringList suffixes();
+
+private:
+    /*!
+     * \brief legacyImage
+     * \return The template image calculated from the source image name.
+     */
+    QFileInfo legacyImage() const;
+
+    /*!
+     * \brief jsonImage
+     * \return The template image read from the corresponding JSON.
+     */
+    QFileInfo jsonImage() const;
+
+private:
+    QFileInfo m_fi;
+};
+
+#endif // TEMPLATEIMAGE_H