coretext: Support variable application fonts

Named instances of variable application fonts are exposed
automatically through CTFontManagerCreateFontDescriptorsFromData()
(and also for the URL equivalent).

The main change here is just to call this instead of the overload
which only returns the first font.

Note that this also updates the test: This is because the conversion
from CoreText normalized weight values to TTF values is not 100%.
In the CoreText code, we map Heavy (0.56) to ExtraBold, but ExtraBold
gets converted to 0.6, which is closer to the CoreText value for Black
(0.62).

To avoid hitting this inconsistency, the QtExtraBold has been changed
to Black weight instead, which resolves to the same on all platforms.

Task-number: QTBUG-108624
Change-Id: Ied6d42e9e3e1ba8b7102936c5be3d285b3d9e07f
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

src/gui/text/coretext/qcoretextfontdatabase.mm

@@ -714,13 +714,20 @@ QStringList QCoreTextFontDatabase::addApplicationFont(const QByteArray &fontData
 
     if (!fontData.isEmpty()) {
         QCFType<CFDataRef> fontDataReference = fontData.toRawCFData();
-        if (QCFType<CTFontDescriptorRef> descriptor = CTFontManagerCreateFontDescriptorFromData(fontDataReference)) {
-            // There's no way to get the data back out of a font descriptor created with
-            // CTFontManagerCreateFontDescriptorFromData, so we attach the data manually.
-            NSDictionary *attributes = @{ kQtFontDataAttribute : [NSValue valueWithPointer:new QByteArray(fontData)] };
-            descriptor = CTFontDescriptorCreateCopyWithAttributes(descriptor, (CFDictionaryRef)attributes);
+        if (QCFType<CFArrayRef> descriptors = CTFontManagerCreateFontDescriptorsFromData(fontDataReference)) {
             CFMutableArrayRef array = CFArrayCreateMutable(kCFAllocatorDefault, 0, &kCFTypeArrayCallBacks);
-            CFArrayAppendValue(array, descriptor);
+            const int count = CFArrayGetCount(descriptors);
+
+            for (int i = 0; i < count; ++i) {
+                CTFontDescriptorRef descriptor = CTFontDescriptorRef(CFArrayGetValueAtIndex(descriptors, i));
+
+                // There's no way to get the data back out of a font descriptor created with
+                // CTFontManagerCreateFontDescriptorFromData, so we attach the data manually.
+                NSDictionary *attributes = @{ kQtFontDataAttribute : [NSValue valueWithPointer:new QByteArray(fontData)] };
+                descriptor = CTFontDescriptorCreateCopyWithAttributes(descriptor, (CFDictionaryRef)attributes);
+                CFArrayAppendValue(array, descriptor);
+            }
+
             fonts = array;
         }
     } else {
@@ -980,5 +987,10 @@ QList<int> QCoreTextFontDatabase::standardSizes() const
     return ret;
 }
 
+bool QCoreTextFontDatabase::supportsVariableApplicationFonts() const
+{
+    return true;
+}
+
 QT_END_NAMESPACE
 

src/gui/text/coretext/qcoretextfontdatabase_p.h

@@ -46,6 +46,7 @@ public:
     QFont defaultFont() const override;
     bool fontsAlwaysScalable() const override;
     QList<int> standardSizes() const override;
+    bool supportsVariableApplicationFonts() const override;
 
     // For iOS and macOS platform themes
     QFont *themeFont(QPlatformTheme::Font) const;

tests/auto/gui/text/qfontdatabase/tst_qfontdatabase.cpp

@@ -534,9 +534,9 @@ void tst_QFontDatabase::variableFont()
 
     {
         QFont font(family);
-        font.setWeight(QFont::ExtraBold);
+        font.setWeight(QFont::Black);
         QCOMPARE(QFontInfo(font).styleName(), u"QtExtraBold"_s);
-        QCOMPARE(QFontInfo(font).weight(), QFont::ExtraBold);
+        QCOMPARE(QFontInfo(font).weight(), int(QFont::Black));
     }
 
     {