Expose "kerning" property for fonts

For text where the content is known, it can be handy to be able
to disable the kerning feature in OpenType to improve performance.

[ChangeLog][Qt Quick][Text] Added "kerning" property to the font
type to support disabling kerning on text.

Task-number: QTBUG-56728
Change-Id: I2e447587a066a7e12c5d38967e0845eaad021014
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

8 files changed, 75 insertions, 0 deletions

diff --git a/src/quick/doc/src/qmltypereference.qdoc b/src/quick/doc/src/qmltypereference.qdoc
index 2406722dbc..cbcf945a11 100644
--- a/src/quick/doc/src/qmltypereference.qdoc
+++ b/src/quick/doc/src/qmltypereference.qdoc
@@ -170,6 +170,7 @@ available when you import \c QtQuick.
     \li \l enumeration \c font.capitalization
     \li \l real \c font.letterSpacing
     \li \l real \c font.wordSpacing
+    \li \l bool \c font.kerning
     \endlist
 
     Example:
diff --git a/src/quick/items/qquicktext.cpp b/src/quick/items/qquicktext.cpp
index 080cc9412e..1bcfbd41f7 100644
--- a/src/quick/items/qquicktext.cpp
+++ b/src/quick/items/qquicktext.cpp
@@ -1499,6 +1499,19 @@ QQuickText::~QQuickText()
     Text { text: "Hello"; renderType: Text.NativeRendering; font.hintingPreference: Font.PreferVerticalHinting }
     \endqml
 */
+
+/*!
+    \qmlproperty bool QtQuick::Text::font.kerning
+    \since 5.10
+
+    Enables or disables the kerning OpenType feature when shaping the text. This may improve performance
+    when creating or changing the text, at the expense of some cosmetic features. The default value
+    is true.
+
+    \qml
+    Text { text: "OATS FLAVOUR WAY"; font.kerning: false }
+    \endqml
+*/
 QFont QQuickText::font() const
 {
     Q_D(const QQuickText);
diff --git a/src/quick/items/qquicktextedit.cpp b/src/quick/items/qquicktextedit.cpp
index 61d610520f..aad380ca30 100644
--- a/src/quick/items/qquicktextedit.cpp
+++ b/src/quick/items/qquicktextedit.cpp
@@ -356,6 +356,19 @@ QString QQuickTextEdit::text() const
 */
 
 /*!
+    \qmlproperty bool QtQuick::TextEdit::font.kerning
+    \since 5.10
+
+    Enables or disables the kerning OpenType feature when shaping the text. This may improve performance
+    when creating or changing the text, at the expense of some cosmetic features. The default value
+    is true.
+
+    \qml
+    Text { text: "OATS FLAVOUR WAY"; kerning: font.false }
+    \endqml
+*/
+
+/*!
     \qmlproperty string QtQuick::TextEdit::text
 
     The text to display.  If the text format is AutoText the text edit will
diff --git a/src/quick/items/qquicktextinput.cpp b/src/quick/items/qquicktextinput.cpp
index a378359c95..d485083820 100644
--- a/src/quick/items/qquicktextinput.cpp
+++ b/src/quick/items/qquicktextinput.cpp
@@ -378,6 +378,19 @@ QString QQuickTextInputPrivate::realText() const
     TextInput { text: "Hello"; renderType: TextInput.NativeRendering; font.hintingPreference: Font.PreferVerticalHinting }
     \endqml
 */
+
+/*!
+    \qmlproperty bool QtQuick::TextInput::font.kerning
+    \since 5.10
+
+    Enables or disables the kerning OpenType feature when shaping the text. This may improve performance
+    when creating or changing the text, at the expense of some cosmetic features. The default value
+    is true.
+
+    \qml
+    Text { text: "OATS FLAVOUR WAY"; font.kerning: false }
+    \endqml
+*/
 QFont QQuickTextInput::font() const
 {
     Q_D(const QQuickTextInput);
diff --git a/src/quick/util/qquickglobal.cpp b/src/quick/util/qquickglobal.cpp
index 1d2f3de1df..6df23cdff5 100644
--- a/src/quick/util/qquickglobal.cpp
+++ b/src/quick/util/qquickglobal.cpp
@@ -302,6 +302,7 @@ public:
         QV4::ScopedValue vweight(scope, obj->get((s = v4->newString(QStringLiteral("weight")))));
         QV4::ScopedValue vwspac(scope, obj->get((s = v4->newString(QStringLiteral("wordSpacing")))));
         QV4::ScopedValue vhint(scope, obj->get((s = v4->newString(QStringLiteral("hintingPreference")))));
+        QV4::ScopedValue vkerning(scope, obj->get((s = v4->newString(QStringLiteral("kerning")))));
 
         // pull out the values, set ok to true if at least one valid field is given.
         if (vbold->isBoolean()) {
@@ -356,6 +357,10 @@ public:
             retn.setHintingPreference(static_cast<QFont::HintingPreference>(vhint->integerValue()));
             if (ok) *ok = true;
         }
+        if (vkerning->isBoolean()) {
+            retn.setKerning(vkerning->booleanValue());
+            if (ok) *ok = true;
+        }
 
         return retn;
     }
diff --git a/src/quick/util/qquickvaluetypes.cpp b/src/quick/util/qquickvaluetypes.cpp
index 4d34c6d661..bc4a72b6ea 100644
--- a/src/quick/util/qquickvaluetypes.cpp
+++ b/src/quick/util/qquickvaluetypes.cpp
@@ -757,6 +757,16 @@ void QQuickFontValueType::setHintingPreference(QQuickFontValueType::HintingPrefe
     v.setHintingPreference(QFont::HintingPreference(hintingPreference));
 }
 
+bool QQuickFontValueType::kerning() const
+{
+    return v.kerning();
+}
+
+void QQuickFontValueType::setKerning(bool b)
+{
+    v.setKerning(b);
+}
+
 QT_END_NAMESPACE
 
 #include "moc_qquickvaluetypes_p.cpp"
diff --git a/src/quick/util/qquickvaluetypes_p.h b/src/quick/util/qquickvaluetypes_p.h
index 4a1598ec5c..a3f35a84ec 100644
--- a/src/quick/util/qquickvaluetypes_p.h
+++ b/src/quick/util/qquickvaluetypes_p.h
@@ -323,6 +323,7 @@ class QQuickFontValueType
     Q_PROPERTY(qreal letterSpacing READ letterSpacing WRITE setLetterSpacing FINAL)
     Q_PROPERTY(qreal wordSpacing READ wordSpacing WRITE setWordSpacing FINAL)
     Q_PROPERTY(HintingPreference hintingPreference READ hintingPreference WRITE setHintingPreference FINAL)
+    Q_PROPERTY(bool kerning READ kerning WRITE setKerning FINAL)
 
 public:
     enum FontWeight { Thin = QFont::Thin,
@@ -393,6 +394,9 @@ public:
 
     HintingPreference hintingPreference() const;
     void setHintingPreference(HintingPreference);
+
+    bool kerning() const;
+    void setKerning(bool b);
 };
 
 QT_END_NAMESPACE
diff --git a/tests/manual/scenegraph_lancelot/data/text/text_nokerning_latin.qml b/tests/manual/scenegraph_lancelot/data/text/text_nokerning_latin.qml
new file mode 100644
index 0000000000..fd1d082c99
--- /dev/null
+++ b/tests/manual/scenegraph_lancelot/data/text/text_nokerning_latin.qml
@@ -0,0 +1,16 @@
+import QtQuick 2.0
+
+Item {
+    width: 320
+    height: 480
+
+    Text {
+        text: "OATS FLAVOUR WAY"
+        anchors.centerIn: parent
+
+        font.family: "Times New Roman"
+        font.italic: true
+        font.pixelSize: 30
+        font.kerning: false
+    }
+}