iOS: Make default system font Helvetica

Without a platform theme implementatin we were relying on
QCoreTextFontDatabase::defaultFont() to return the system font.

This didn't work because it reported the system font that iOS reports,
'.Helvetica Neue UI', which is a private font that does not get added
to our font database. The result was that we picked the first font in
the list of known fonts -- in this case 'Academy Engraved LET'.

We now implement QIOSTheme::font(), which takes precedence over the
font database's default font, and hard-code the system font to
'Helvetica', since Qt does not yet have the concept of private
system fonts.

Change-Id: I901cf9c2b662ea2795212376b84b8391be2efbbe
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@digia.com>

1 files changed, 27 insertions, 0 deletions

diff --git a/src/plugins/platforms/ios/qiostheme.mm b/src/plugins/platforms/ios/qiostheme.mm
index 6e54b9cb3b..f98781f8a7 100644
--- a/src/plugins/platforms/ios/qiostheme.mm
+++ b/src/plugins/platforms/ios/qiostheme.mm
@@ -44,6 +44,11 @@
 #include <QtCore/QStringList>
 #include <QtCore/QVariant>
 
+#include <QtGui/QFont>
+
+#include <UIKit/UIFont.h>
+#include <UIKit/UIInterface.h>
+
 QT_BEGIN_NAMESPACE
 
 const char *QIOSTheme::name = "ios";
@@ -66,4 +71,26 @@ QVariant QIOSTheme::themeHint(ThemeHint hint) const
     }
 }
 
+const QFont *QIOSTheme::font(Font type) const
+{
+    static QHash<QPlatformTheme::Font, QFont *> fonts;
+    if (fonts.isEmpty()) {
+        // The real system font on iOS is '.Helvetica Neue UI', as returned by both [UIFont systemFontOfSize]
+        // and CTFontCreateUIFontForLanguage(kCTFontSystemFontType, ...), but this font is not included when
+        // populating the available fonts in QCoreTextFontDatabase::populateFontDatabase(), since the font
+        // is internal to iOS and not supposed to be used by applications. We could potentially add this
+        // font to the font-database, but it would then show up when enumerating user fonts from Qt
+        // applications since we don't have a flag in Qt to mark a font as a private system font.
+        // For now we hard-code the font to Helvetica, which should be very close to the actual
+        // system font.
+        QLatin1String systemFontFamilyName("Helvetica");
+        fonts.insert(QPlatformTheme::SystemFont, new QFont(systemFontFamilyName, [UIFont systemFontSize]));
+        fonts.insert(QPlatformTheme::SmallFont, new QFont(systemFontFamilyName, [UIFont smallSystemFontSize]));
+        fonts.insert(QPlatformTheme::LabelFont, new QFont(systemFontFamilyName, [UIFont labelFontSize]));
+        fonts.insert(QPlatformTheme::PushButtonFont, new QFont(systemFontFamilyName, [UIFont buttonFontSize]));
+    }
+
+    return fonts.value(type, 0);
+}
+
 QT_END_NAMESPACE