Implement API for enabling / disabling OpenType features

Similar to the font-features-settings in CSS, this is a low-level
API that allows you to pass the information to the shaper in order
to enable or disable specific font features by name.

[ChangeLog][QtGui][Text] Added an API to QFont which makes it
possible to enable and disable specific typographic features
in OpenType fonts.

Change-Id: Ib48c678f3b97a5a562b08ae34dc895800c8885c0
Reviewed-by: Lars Knoll <lars@knoll.priv.no>

11 files changed, 673 insertions, 17 deletions

diff --git a/src/gui/text/qfont.cpp b/src/gui/text/qfont.cpp
index 1efe3c06d8..94529badec 100644
--- a/src/gui/text/qfont.cpp
+++ b/src/gui/text/qfont.cpp
@@ -213,7 +213,7 @@ QFontPrivate::QFontPrivate(const QFontPrivate &other)
       strikeOut(other.strikeOut), kerning(other.kerning),
       capital(other.capital), letterSpacingIsAbsolute(other.letterSpacingIsAbsolute),
       letterSpacing(other.letterSpacing), wordSpacing(other.wordSpacing),
-      scFont(other.scFont)
+      fontFeatures(other.fontFeatures), scFont(other.scFont)
 {
     if (scFont && scFont != this)
         scFont->ref.ref();
@@ -343,9 +343,20 @@ void QFontPrivate::resolve(uint mask, const QFontPrivate *other)
         wordSpacing = other->wordSpacing;
     if (! (mask & QFont::CapitalizationResolved))
         capital = other->capital;
+
+    if (!(mask & QFont::FontFeaturesResolved))
+        fontFeatures = other->fontFeatures;
 }
 
+void QFontPrivate::setFontFeature(quint32 tag, quint32 value)
+{
+    fontFeatures.insert(tag, value);
+}
 
+void QFontPrivate::unsetFontFeature(quint32 tag)
+{
+    fontFeatures.remove(tag);
+}
 
 
 QFontEngineData::QFontEngineData()
@@ -1748,6 +1759,7 @@ bool QFont::operator==(const QFont &f) const
                 && f.d->letterSpacingIsAbsolute == d->letterSpacingIsAbsolute
                 && f.d->letterSpacing == d->letterSpacing
                 && f.d->wordSpacing == d->wordSpacing
+                && f.d->fontFeatures == d->fontFeatures
             ));
 }
 
@@ -1785,7 +1797,21 @@ bool QFont::operator<(const QFont &f) const
 
     int f1attrs = (f.d->underline << 3) + (f.d->overline << 2) + (f.d->strikeOut<<1) + f.d->kerning;
     int f2attrs = (d->underline << 3) + (d->overline << 2) + (d->strikeOut<<1) + d->kerning;
-    return f1attrs < f2attrs;
+    if (f1attrs != f2attrs) return f1attrs < f2attrs;
+
+    if (d->fontFeatures.size() != f.d->fontFeatures.size())
+        return f.d->fontFeatures.size() < d->fontFeatures.size();
+
+    auto it = d->fontFeatures.constBegin();
+    auto jt = f.d->fontFeatures.constBegin();
+    for (; it != d->fontFeatures.constEnd(); ++it, ++jt) {
+        if (it.key() != jt.key())
+            return jt.key() < it.key();
+        if (it.value() != jt.value())
+            return jt.value() < it.value();
+    }
+
+    return false;
 }
 
 
@@ -2206,6 +2232,179 @@ void QFont::cacheStatistics()
 {
 }
 
+/*!
+    \since 6.6
+
+    Applies integer values to specific OpenType features when shaping the text based on the contents
+    in \a fontFeatures. This provides advanced access to the font shaping process, and can be used
+    to support font features that are otherwise not covered in the API.
+
+    An OpenType feature is defined by a 32-bit tag (encoded from the four-character name of the
+    table by using the stringToTag() function), as well as an integer value.
+
+    This integer value passed along with the tag in most cases represents a boolean value: A zero
+    value means the feature is disabled, and a non-zero value means it is enabled. For certain
+    font features, however, it may have other intepretations. For example, when applied to the
+    \c salt feature, the value is an index that specifies the stylistic alternative to use.
+
+    For example, the \c frac font feature will convert diagonal fractions separated with a slash
+    (such as \c 1/2) with a different representation. Typically this will involve baking the full
+    fraction into a single character width (such as \c ½).
+
+    If a font supports the \c frac feature, then it can be enabled in the shaper by setting
+    \c{fontFeatures[stringToTag("frac")] = 1} in the font feature map.
+
+    This function will overwrite the current list of explicit font features. Use setFontFeature() or
+    unsetFontFeature() to set or unset individual features.
+
+    \note By default, Qt will enable and disable certain font features based on other font
+    properties. In particular, the \c kern feature will be enabled/disabled depending on the
+    \l kerning() property of the QFont. In addition, all ligature features
+    (\c liga, \c clig, \c dlig, \c hlig) will be disabled if a \l letterSpacing() is applied,
+    but only for writing systems where the use of ligature is cosmetic. For writing systems where
+    ligatures are required, the features will remain in their default state. The values set using
+    setFontFeatures() and related functions will override the default behavior. If, for instance,
+    the \c{fontFeatures[stringToTag("kern")]} is set to 1, then kerning will always be enabled,
+    regardless of whether the kerning property is set to false. Similarly, if it is set to 0, then
+    it will always be disabled. To reset a font feature to its default behavior, you can unset it
+    in the fontFeatures hash, for example by using unsetFontFeature().
+
+    \sa setFontFeature(), unsetFontFeature(), fontFeatures()
+*/
+void QFont::setFontFeatures(const QHash<quint32, quint32> &fontFeatures)
+{
+    d->detachButKeepEngineData(this);
+    d->fontFeatures = fontFeatures;
+    resolve_mask |= QFont::FontFeaturesResolved;
+}
+
+/*!
+    \since 6.6
+    \overload
+
+    Sets the \a value for a specific font feature \a tag. This is an advanced feature which can be
+    used to enable or disable specific OpenType features if they are available in the font. See
+    \l setFontFeatures() for more details.
+
+    \sa setFontFeatures(), unsetFontFeature(), fontFeatures()
+*/
+void QFont::setFontFeature(quint32 tag, quint32 value)
+{
+    d->detachButKeepEngineData(this);
+    d->setFontFeature(tag, value);
+    resolve_mask |= QFont::FontFeaturesResolved;
+}
+
+/*!
+    \since 6.6
+    \overload
+
+    Sets the \a value of a specific \a fontFeature. This is an advanced feature which can be used to
+    enable or disable specific OpenType features if they are available in the font. See
+    \l setFontFeatures() for more details.
+
+    \note This is equivalent to calling setFontFeature(stringToTag(fontFeature), value).
+
+    \sa setFontFeatures(), unsetFontFeature(), fontFeatures()
+*/
+void QFont::setFontFeature(const char *fontFeature, quint32 value)
+{
+    setFontFeature(stringToTag(fontFeature), value);
+}
+
+/*!
+    \since 6.6
+    \overload
+
+    Unsets the \a fontFeature from the map of explicitly enabled/disabled features.
+
+    \note Even if the feature has not previously been added, this will mark the font features map
+    as modified in this QFont, so that it will take precedence when resolving against other fonts.
+
+    Unsetting an existing feature on the QFont reverts behavior to the default. See
+    \l setFontFeatures() for more details.
+
+    \sa setFontFeatures(), setFontFeature(), fontFeatures()
+*/
+void QFont::unsetFontFeature(quint32 tag)
+{
+    d->detachButKeepEngineData(this);
+    d->unsetFontFeature(tag);
+    resolve_mask |= QFont::FontFeaturesResolved;
+}
+
+/*!
+    \since 6.6
+    \overload
+
+    Unsets the \a fontFeature from the map of explicitly enabled/disabled features.
+
+    \note Even if the feature has not previously been added, this will mark the font features map
+    as modified in this QFont, so that it will take precedence when resolving against other fonts.
+
+    Unsetting an existing feature on the QFont reverts behavior to the default. See
+    \l setFontFeatures() for more details.
+
+    \note This is equivalent to calling unsetFontFeature(stringToTag(fontFeature)).
+
+    \sa setFontFeatures(), setFontFeature(), fontFeatures()
+*/
+void QFont::unsetFontFeature(const char *fontFeature)
+{
+    unsetFontFeature(stringToTag(fontFeature));
+}
+
+/*!
+    \since 6.6
+
+    Returns the hash of explicitly set font features in the QFont. By default this map is empty and
+    the shaping process will use default features based on other font or text properties.
+
+    Unsetting an existing feature on the QFont reverts behavior to the default. See
+    \l setFontFeatures() for more details.
+
+    The key of the returned QHash refers to the font table tag as it's encoded in the font
+    file. It can be converted to a QByteArray using the tagToString() function.
+
+    \sa setFontFeatures(), setFontFeature(), unsetFontFeature()
+*/
+QHash<quint32, quint32> QFont::fontFeatures() const
+{
+    return d->fontFeatures;
+}
+
+/*!
+    \since 6.6
+
+    Returns the decoded name for \a tag.
+
+    \sa setFontFeatures(), setFontFeature(), unsetFontFeature(), stringToTag()
+*/
+QByteArray QFont::tagToString(quint32 tag)
+{
+    char str[4] =
+        { char((tag & 0xff000000) >> 24),
+          char((tag & 0x00ff0000) >> 16),
+          char((tag & 0x0000ff00) >> 8),
+          char((tag & 0x000000ff)) };
+    return QByteArray(str, 4);
+}
+
+/*!
+    \since 6.6
+
+    Returns the encoded tag for \a name. The \a name must be a null-terminated string of exactly
+    four characters. Returns 0 on error.
+
+    \sa setFontFeatures(), setFontFeature(), unsetFontFeature(), tagToString()
+*/
+quint32 QFont::stringToTag(const char *name)
+{
+    if (qstrlen(name) != 4)
+        return 0;
+
+    return MAKE_TAG(name[0], name[1], name[2], name[3]);
+}
 
 extern QStringList qt_fallbacksForFamily(const QString &family, QFont::Style style,
                                          QFont::StyleHint styleHint, QChar::Script script);
@@ -2343,6 +2542,8 @@ QDataStream &operator<<(QDataStream &s, const QFont &font)
         else
             s << font.d->request.families;
     }
+    if (s.version() >= QDataStream::Qt_6_6)
+        s << font.d->fontFeatures;
     return s;
 }
 
@@ -2457,6 +2658,11 @@ QDataStream &operator>>(QDataStream &s, QFont &font)
         else
             font.d->request.families = value;
     }
+    if (s.version() >= QDataStream::Qt_6_6) {
+        font.d->fontFeatures.clear();
+        s >> font.d->fontFeatures;
+    }
+
     return s;
 }
 
diff --git a/src/gui/text/qfont.h b/src/gui/text/qfont.h
index 6a5c890395..6fa5b7b044 100644
--- a/src/gui/text/qfont.h
+++ b/src/gui/text/qfont.h
@@ -126,7 +126,8 @@ public:
         HintingPreferenceResolved   = 0x8000,
         StyleNameResolved           = 0x10000,
         FamiliesResolved            = 0x20000,
-        AllPropertiesResolved       = 0x3ffff
+        FontFeaturesResolved        = 0x40000,
+        AllPropertiesResolved       = 0x7ffff
     };
     Q_ENUM(ResolveProperties)
 
@@ -206,6 +207,16 @@ public:
     void setHintingPreference(HintingPreference hintingPreference);
     HintingPreference hintingPreference() const;
 
+    void setFontFeature(const char *fontFeature, quint32 value);
+    void setFontFeature(quint32 tag, quint32 value);
+    void setFontFeatures(const QHash<quint32, quint32> &fontFeatures);
+    void unsetFontFeature(quint32 tag);
+    void unsetFontFeature(const char *tag);
+    QHash<quint32, quint32> fontFeatures() const;
+
+    static QByteArray tagToString(quint32 tag);
+    static quint32 stringToTag(const char *tagString);
+
     // dupicated from QFontInfo
     bool exactMatch() const;
 
diff --git a/src/gui/text/qfont_p.h b/src/gui/text/qfont_p.h
index 13738bb096..ef52410a0c 100644
--- a/src/gui/text/qfont_p.h
+++ b/src/gui/text/qfont_p.h
@@ -164,6 +164,7 @@ public:
 
     QFixed letterSpacing;
     QFixed wordSpacing;
+    QHash<quint32, quint32> fontFeatures;
 
     mutable QFontPrivate *scFont;
     QFont smallCapsFont() const { return QFont(smallCapsFontPrivate()); }
@@ -178,6 +179,9 @@ public:
 
     static void detachButKeepEngineData(QFont *font);
 
+    void setFontFeature(quint32 tag, quint32 value);
+    void unsetFontFeature(quint32 tag);
+
 private:
     QFontPrivate &operator=(const QFontPrivate &) { return *this; }
 };
diff --git a/src/gui/text/qtextengine.cpp b/src/gui/text/qtextengine.cpp
index eded3e3f33..a8e70c17bf 100644
--- a/src/gui/text/qtextengine.cpp
+++ b/src/gui/text/qtextengine.cpp
@@ -1404,6 +1404,7 @@ void QTextEngine::shapeText(int item) const
     bool kerningEnabled;
     bool letterSpacingIsAbsolute;
     bool shapingEnabled = false;
+    QHash<quint32, quint32> fontFeatures;
     QFixed letterSpacing, wordSpacing;
 #ifndef QT_NO_RAWFONT
     if (useRawFont) {
@@ -1417,6 +1418,7 @@ void QTextEngine::shapeText(int item) const
         wordSpacing = QFixed::fromReal(font.wordSpacing());
         letterSpacing = QFixed::fromReal(font.letterSpacing());
         letterSpacingIsAbsolute = true;
+        fontFeatures = font.d->fontFeatures;
     } else
 #endif
     {
@@ -1429,6 +1431,7 @@ void QTextEngine::shapeText(int item) const
         letterSpacingIsAbsolute = font.d->letterSpacingIsAbsolute;
         letterSpacing = font.d->letterSpacing;
         wordSpacing = font.d->wordSpacing;
+        fontFeatures = font.d->fontFeatures;
 
         if (letterSpacingIsAbsolute && letterSpacing.value())
             letterSpacing *= font.d->dpi / qt_defaultDpiY();
@@ -1482,7 +1485,14 @@ void QTextEngine::shapeText(int item) const
 
 #if QT_CONFIG(harfbuzz)
     if (Q_LIKELY(shapingEnabled)) {
-        si.num_glyphs = shapeTextWithHarfbuzzNG(si, string, itemLength, fontEngine, itemBoundaries, kerningEnabled, letterSpacing != 0);
+        si.num_glyphs = shapeTextWithHarfbuzzNG(si,
+                                                string,
+                                                itemLength,
+                                                fontEngine,
+                                                itemBoundaries,
+                                                kerningEnabled,
+                                                letterSpacing != 0,
+                                                fontFeatures);
     } else
 #endif
     {
@@ -1594,7 +1604,8 @@ int QTextEngine::shapeTextWithHarfbuzzNG(const QScriptItem &si,
                                          QFontEngine *fontEngine,
                                          const QList<uint> &itemBoundaries,
                                          bool kerningEnabled,
-                                         bool hasLetterSpacing) const
+                                         bool hasLetterSpacing,
+                                         const QHash<quint32, quint32> &fontFeatures) const
 {
     uint glyphs_shaped = 0;
 
@@ -1648,14 +1659,24 @@ int QTextEngine::shapeTextWithHarfbuzzNG(const QScriptItem &si,
                                          || script == QChar::Script_Khmer || script == QChar::Script_Nko);
 
             bool dontLigate = hasLetterSpacing && !scriptRequiresOpenType;
-            const hb_feature_t features[5] = {
-                { HB_TAG('k','e','r','n'), !!kerningEnabled, HB_FEATURE_GLOBAL_START, HB_FEATURE_GLOBAL_END },
-                { HB_TAG('l','i','g','a'), false, HB_FEATURE_GLOBAL_START, HB_FEATURE_GLOBAL_END },
-                { HB_TAG('c','l','i','g'), false, HB_FEATURE_GLOBAL_START, HB_FEATURE_GLOBAL_END },
-                { HB_TAG('d','l','i','g'), false, HB_FEATURE_GLOBAL_START, HB_FEATURE_GLOBAL_END },
-                { HB_TAG('h','l','i','g'), false, HB_FEATURE_GLOBAL_START, HB_FEATURE_GLOBAL_END }
-            };
-            const int num_features = dontLigate ? 5 : 1;
+
+            QHash<quint32, quint32> features;
+            features.insert(HB_TAG('k','e','r','n'), !!kerningEnabled);
+            if (dontLigate) {
+                features.insert(HB_TAG('l','i','g','a'), false);
+                features.insert(HB_TAG('c','l','i','g'), false);
+                features.insert(HB_TAG('d','l','i','g'), false);
+                features.insert(HB_TAG('h','l','i','g'), false);
+            }
+            features.insert(fontFeatures);
+
+            QVarLengthArray<hb_feature_t, 16> featureArray;
+            for (auto it = features.constBegin(); it != features.constEnd(); ++it) {
+                featureArray.append({ it.key(),
+                                      it.value(),
+                                      HB_FEATURE_GLOBAL_START,
+                                      HB_FEATURE_GLOBAL_END });
+            }
 
             // whitelist cross-platforms shapers only
             static const char *shaper_list[] = {
@@ -1665,7 +1686,11 @@ int QTextEngine::shapeTextWithHarfbuzzNG(const QScriptItem &si,
                 nullptr
             };
 
-            bool shapedOk = hb_shape_full(hb_font, buffer, features, num_features, shaper_list);
+            bool shapedOk = hb_shape_full(hb_font,
+                                          buffer,
+                                          featureArray.constData(),
+                                          features.size(),
+                                          shaper_list);
             if (Q_UNLIKELY(!shapedOk)) {
                 hb_buffer_destroy(buffer);
                 return 0;
diff --git a/src/gui/text/qtextengine_p.h b/src/gui/text/qtextengine_p.h
index 59e332c64a..a6015cc311 100644
--- a/src/gui/text/qtextengine_p.h
+++ b/src/gui/text/qtextengine_p.h
@@ -621,9 +621,14 @@ private:
     void addRequiredBoundaries() const;
     void shapeText(int item) const;
 #if QT_CONFIG(harfbuzz)
-    int shapeTextWithHarfbuzzNG(const QScriptItem &si, const ushort *string, int itemLength,
-                                QFontEngine *fontEngine, const QList<uint> &itemBoundaries,
-                                bool kerningEnabled, bool hasLetterSpacing) const;
+    int shapeTextWithHarfbuzzNG(const QScriptItem &si,
+                                const ushort *string,
+                                int itemLength,
+                                QFontEngine *fontEngine,
+                                const QList<uint> &itemBoundaries,
+                                bool kerningEnabled,
+                                bool hasLetterSpacing,
+                                const QHash<quint32, quint32> &fontFeatures) const;
 #endif
 
     int endOfLine(int lineNum);
diff --git a/tests/manual/fontfeatures/fontfeatures.pro b/tests/manual/fontfeatures/fontfeatures.pro
new file mode 100644
index 0000000000..62769072b4
--- /dev/null
+++ b/tests/manual/fontfeatures/fontfeatures.pro
@@ -0,0 +1,17 @@
+TEMPLATE = app
+TARGET = fontfeatures
+INCLUDEPATH += .
+QT += widgets
+
+# You can make your code fail to compile if you use deprecated APIs.
+# In order to do so, uncomment the following line.
+# Please consult the documentation of the deprecated API in order to know
+# how to port your code away from it.
+# You can also select to disable deprecated APIs only up to a certain version of Qt.
+#DEFINES += QT_DISABLE_DEPRECATED_UP_TO=0x060000 # disables all APIs deprecated in Qt 6.0.0 and earlier
+
+# Input
+HEADERS += mainwindow.h
+FORMS += mainwindow.ui
+SOURCES += main.cpp \
+           mainwindow.cpp \
diff --git a/tests/manual/fontfeatures/main.cpp b/tests/manual/fontfeatures/main.cpp
new file mode 100644
index 0000000000..9c5bc17874
--- /dev/null
+++ b/tests/manual/fontfeatures/main.cpp
@@ -0,0 +1,14 @@
+// Copyright (C) 2023 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
+
+#include "mainwindow.h"
+
+#include <QApplication>
+
+int main(int argc, char *argv[])
+{
+    QApplication a(argc, argv);
+    MainWindow w;
+    w.show();
+    return a.exec();
+}
diff --git a/tests/manual/fontfeatures/mainwindow.cpp b/tests/manual/fontfeatures/mainwindow.cpp
new file mode 100644
index 0000000000..5342f7c89b
--- /dev/null
+++ b/tests/manual/fontfeatures/mainwindow.cpp
@@ -0,0 +1,225 @@
+// Copyright (C) 2023 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
+
+#include "mainwindow.h"
+#include "ui_mainwindow.h"
+
+MainWindow::MainWindow(QWidget *parent)
+    : QMainWindow(parent)
+    , ui(new Ui::MainWindow)
+{
+    ui->setupUi(this);
+
+    setup();
+    updateSampleText();
+}
+
+MainWindow::~MainWindow()
+{
+    delete ui;
+}
+
+void MainWindow::updateSampleText()
+{
+    QFont font = ui->fontComboBox->currentFont();
+    font.setPixelSize(54);
+
+    for (int i = 0; i < ui->lwFeatures->count(); ++i) {
+        QListWidgetItem *it = ui->lwFeatures->item(i);
+        if (it->checkState() != Qt::PartiallyChecked) {
+            QByteArray ba = it->text().toLatin1();
+            font.setFontFeature(ba, !!it->checkState());
+        }
+    }
+
+    ui->lSampleDisplay->setFont(font);
+    ui->lSampleDisplay->setText(ui->leSampleText->text());
+}
+
+void MainWindow::enableAll()
+{
+    for (int i = 0; i < ui->lwFeatures->count(); ++i) {
+        QListWidgetItem *it = ui->lwFeatures->item(i);
+        it->setCheckState(Qt::Checked);
+    }
+}
+
+void MainWindow::disableAll()
+{
+    for (int i = 0; i < ui->lwFeatures->count(); ++i) {
+        QListWidgetItem *it = ui->lwFeatures->item(i);
+        it->setCheckState(Qt::Unchecked);
+    }
+}
+
+void MainWindow::reset()
+{
+    for (int i = 0; i < ui->lwFeatures->count(); ++i) {
+        QListWidgetItem *it = ui->lwFeatures->item(i);
+        it->setCheckState(Qt::PartiallyChecked);
+    }
+}
+
+void MainWindow::setup()
+{
+    connect(ui->fontComboBox, &QFontComboBox::currentFontChanged, this, &MainWindow::updateSampleText);
+    connect(ui->leSampleText, &QLineEdit::textChanged, this, &MainWindow::updateSampleText);
+    connect(ui->lwFeatures, &QListWidget::itemChanged, this, &MainWindow::updateSampleText);
+    connect(ui->pbEnableAll, &QPushButton::clicked, this, &MainWindow::enableAll);
+    connect(ui->pbDisableAll, &QPushButton::clicked, this, &MainWindow::disableAll);
+    connect(ui->pbReset, &QPushButton::clicked, this, &MainWindow::reset);
+
+    QList<QByteArray> featureList =
+    {
+        "aalt",
+        "abvf",
+        "abvm",
+        "abvs",
+        "afrc",
+        "akhn",
+        "blwf",
+        "blwm",
+        "blws",
+        "calt",
+        "case",
+        "ccmp",
+        "cfar",
+        "chws",
+        "cjct",
+        "clig",
+        "cpct",
+        "cpsp",
+        "cswh",
+        "curs",
+        "cv01",
+        "c2pc",
+        "c2sc",
+        "dist",
+        "dlig",
+        "dnom",
+        "dtls",
+        "expt",
+        "falt",
+        "fin2",
+        "fin3",
+        "fina",
+        "flac",
+        "frac",
+        "fwid",
+        "half",
+        "haln",
+        "halt",
+        "hist",
+        "hkna",
+        "hlig",
+        "hngl",
+        "hojo",
+        "hwid",
+        "init",
+        "isol",
+        "ital",
+        "jalt",
+        "jp78",
+        "jp83",
+        "jp90",
+        "jp04",
+        "kern",
+        "lfbd",
+        "liga",
+        "ljmo",
+        "lnum",
+        "locl",
+        "ltra",
+        "ltrm",
+        "mark",
+        "med2",
+        "medi",
+        "mgrk",
+        "mkmk",
+        "mset",
+        "nalt",
+        "nlck",
+        "nukt",
+        "numr",
+        "onum",
+        "opbd",
+        "ordn",
+        "ornm",
+        "palt",
+        "pcap",
+        "pkna",
+        "pnum",
+        "pref",
+        "pres",
+        "pstf",
+        "psts",
+        "pwid",
+        "qwid",
+        "rand",
+        "rclt",
+        "rkrf",
+        "rlig",
+        "rphf",
+        "rtbd",
+        "rtla",
+        "rtlm",
+        "ruby",
+        "rvrn",
+        "salt",
+        "sinf",
+        "size",
+        "smcp",
+        "smpl",
+        "ss01",
+        "ss02",
+        "ss03",
+        "ss04",
+        "ss05",
+        "ss06",
+        "ss07",
+        "ss08",
+        "ss09",
+        "ss10",
+        "ss11",
+        "ss12",
+        "ss13",
+        "ss14",
+        "ss15",
+        "ss16",
+        "ss17",
+        "ss18",
+        "ss19",
+        "ss20",
+        "ssty",
+        "stch",
+        "subs",
+        "sups",
+        "swsh",
+        "titl",
+        "tjmo",
+        "tnam",
+        "tnum",
+        "trad",
+        "twid",
+        "unic",
+        "valt",
+        "vatu",
+        "vchw",
+        "vert",
+        "vhal",
+        "vjmo",
+        "vkna",
+        "vkrn",
+        "vpal",
+        "vrt2",
+        "vrtr",
+        "zero"
+    };
+
+    for (auto it = featureList.constBegin(); it != featureList.constEnd(); ++it) {
+        QListWidgetItem *item = new QListWidgetItem(*it);
+        item->setFlags(Qt::ItemIsUserTristate | Qt::ItemIsUserCheckable | Qt::ItemIsEnabled);
+        item->setCheckState(Qt::PartiallyChecked);
+        ui->lwFeatures->addItem(item);
+    }
+}
diff --git a/tests/manual/fontfeatures/mainwindow.h b/tests/manual/fontfeatures/mainwindow.h
new file mode 100644
index 0000000000..c8248e7558
--- /dev/null
+++ b/tests/manual/fontfeatures/mainwindow.h
@@ -0,0 +1,32 @@
+// Copyright (C) 2023 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
+
+#ifndef MAINWINDOW_H
+#define MAINWINDOW_H
+
+#include <QMainWindow>
+
+QT_BEGIN_NAMESPACE
+namespace Ui { class MainWindow; }
+QT_END_NAMESPACE
+
+class MainWindow : public QMainWindow
+{
+    Q_OBJECT
+
+public:
+    MainWindow(QWidget *parent = nullptr);
+    ~MainWindow();
+
+private slots:
+    void updateSampleText();
+    void enableAll();
+    void disableAll();
+    void reset();
+
+private:
+    Ui::MainWindow *ui;
+
+    void setup();
+};
+#endif // MAINWINDOW_H
diff --git a/tests/manual/fontfeatures/mainwindow.ui b/tests/manual/fontfeatures/mainwindow.ui
new file mode 100644
index 0000000000..17f56c5a01
--- /dev/null
+++ b/tests/manual/fontfeatures/mainwindow.ui
@@ -0,0 +1,116 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>MainWindow</class>
+ <widget class="QMainWindow" name="MainWindow">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>800</width>
+    <height>600</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string>MainWindow</string>
+  </property>
+  <widget class="QWidget" name="centralwidget">
+   <layout class="QHBoxLayout" name="horizontalLayout_3">
+    <item>
+     <layout class="QVBoxLayout" name="verticalLayout">
+      <item>
+       <widget class="QFontComboBox" name="fontComboBox"/>
+      </item>
+      <item>
+       <layout class="QHBoxLayout" name="horizontalLayout">
+        <item>
+         <widget class="QLabel" name="label">
+          <property name="text">
+           <string>Sample text:</string>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <widget class="QLineEdit" name="leSampleText">
+          <property name="text">
+           <string>Foobar</string>
+          </property>
+         </widget>
+        </item>
+       </layout>
+      </item>
+      <item>
+       <layout class="QHBoxLayout" name="horizontalLayout_2">
+        <item>
+         <widget class="QPushButton" name="pbEnableAll">
+          <property name="text">
+           <string>Enable all</string>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <widget class="QPushButton" name="pbDisableAll">
+          <property name="text">
+           <string>Disable all</string>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <widget class="QPushButton" name="pbReset">
+          <property name="text">
+           <string>Reset</string>
+          </property>
+         </widget>
+        </item>
+       </layout>
+      </item>
+      <item>
+       <widget class="QListWidget" name="lwFeatures">
+        <property name="alternatingRowColors">
+         <bool>true</bool>
+        </property>
+        <property name="flow">
+         <enum>QListView::TopToBottom</enum>
+        </property>
+        <property name="isWrapping" stdset="0">
+         <bool>false</bool>
+        </property>
+        <property name="viewMode">
+         <enum>QListView::ListMode</enum>
+        </property>
+        <property name="uniformItemSizes">
+         <bool>true</bool>
+        </property>
+       </widget>
+      </item>
+     </layout>
+    </item>
+    <item>
+     <widget class="QLabel" name="lSampleDisplay">
+      <property name="sizePolicy">
+       <sizepolicy hsizetype="MinimumExpanding" vsizetype="Preferred">
+        <horstretch>0</horstretch>
+        <verstretch>0</verstretch>
+       </sizepolicy>
+      </property>
+      <property name="text">
+       <string>LABEL</string>
+      </property>
+     </widget>
+    </item>
+   </layout>
+  </widget>
+  <widget class="QMenuBar" name="menubar">
+   <property name="geometry">
+    <rect>
+     <x>0</x>
+     <y>0</y>
+     <width>800</width>
+     <height>21</height>
+    </rect>
+   </property>
+  </widget>
+  <widget class="QStatusBar" name="statusbar"/>
+ </widget>
+ <resources/>
+ <connections/>
+</ui>
diff --git a/tests/manual/manual.pro b/tests/manual/manual.pro
index 7bb92bb453..3519fc1148 100644
--- a/tests/manual/manual.pro
+++ b/tests/manual/manual.pro
@@ -5,6 +5,7 @@ SUBDIRS = \
 filetest \
 embeddedintoforeignwindow \
 foreignwindows \
+fontfeatures \
 gestures \
 highdpi \
 inputmethodhints \