Add support font-kerning CSS3 property

Change-Id: Ie3894481ded40d20091bd0103ac426c1086f943f
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>

src/gui/doc/src/richtext.qdoc

@@ -1197,6 +1197,9 @@
     \row    \li \c text-transform
             \li [ uppercase | lowercase ]
             \li Select the transformation that will be performed on the text prior to displaying it.
+    \row    \li \c font-kerning
+            \li [ normal | none ]
+            \li Enables or disables kerning between text characters.
     \row    \li \c font-variant
             \li small-caps
             \li Perform the smallcaps transformation on the text prior to displaying it.

src/gui/text/qcssparser.cpp

@@ -115,6 +115,7 @@ static const QCssKnownValue properties[NumProperties - 1] = {
     { "float", Float },
     { "font", Font },
     { "font-family", FontFamily },
+    { "font-kerning", FontKerning },
     { "font-size", FontSize },
     { "font-style", FontStyle },
     { "font-variant", FontVariant },
@@ -368,6 +369,7 @@ static inline bool isInheritable(Property propertyId)
 {
     switch (propertyId) {
     case Font:
+    case FontKerning:
     case FontFamily:
     case FontSize:
     case FontStyle:
@@ -1142,6 +1144,19 @@ static bool setFontStyleFromValue(const QCss::Value &value, QFont *font)
     return false;
 }
 
+static bool setFontKerningFromValue(const QCss::Value &value, QFont *font)
+{
+    if (value.type != Value::KnownIdentifier)
+        return false ;
+    switch (value.variant.toInt()) {
+        case Value_Normal: font->setKerning(true); return true;
+        case Value_None: font->setKerning(false); return true;
+        case Value_Auto: return true;
+        default: break;
+    }
+    return false;
+}
+
 static bool setFontWeightFromValue(const QCss::Value &value, QFont *font)
 {
     if (value.type == Value::KnownIdentifier) {
@@ -1274,6 +1289,7 @@ bool ValueExtractor::extractFont(QFont *font, int *fontSizeAdjustment)
             case FontStyle: setFontStyleFromValue(val, font); break;
             case FontWeight: setFontWeightFromValue(val, font); break;
             case FontFamily: setFontFamilyFromValues(decl.d->values, font); break;
+            case FontKerning: setFontKerningFromValue(val, font); break;
             case TextDecoration: setTextDecorationFromValues(decl.d->values, font); break;
             case Font: parseShorthandFontProperty(decl.d->values, font, fontSizeAdjustment); break;
             case FontVariant: setFontVariantFromValue(val, font); break;

src/gui/text/qcssparser_p.h

@@ -195,6 +195,7 @@ enum Property {
     QtListNumberSuffix,
     LineHeight,
     QtLineHeightType,
+    FontKerning,
     NumProperties
 };