Fix QQuickTheme::font() and palette()

Respect fonts and palettes from :/qtquickcontrols2.conf, but don't
blatantly override the platform fonts and palettes with null values
if the fonts and palettes are not set in :/qtquickcontrols2.conf.

Even though fonts and palettes have technically same problem, testing
the system palette is hard with 5.11 since QQuickDefaultTheme is a
platform proxy theme and provides a custom system palette. It should
be possible to have tst_palette::systemPalette() in dev, though, where
we have removed the inheritance between QQuickTheme and QPlatformTheme.

Task-number: QTBUG-66430
Change-Id: I6dfe678ccdc7e3990320c120612cfcc68723264d
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

1 files changed, 6 insertions, 4 deletions

diff --git a/src/quickcontrols2/qquicktheme.cpp b/src/quickcontrols2/qquicktheme.cpp
index 06a66bfd..3643e975 100644
--- a/src/quickcontrols2/qquicktheme.cpp
+++ b/src/quickcontrols2/qquicktheme.cpp
@@ -134,14 +134,16 @@ QQuickTheme::QQuickTheme(const QString &style)
 
 const QFont *QQuickTheme::font(Font type) const
 {
-    Q_UNUSED(type);
-    return m_styleFont.data();
+    if (m_styleFont)
+        return m_styleFont.data();
+    return QQuickProxyTheme::font(type);
 }
 
 const QPalette *QQuickTheme::palette(Palette type) const
 {
-    Q_UNUSED(type);
-    return m_stylePalette.data();
+    if (m_stylePalette)
+        return m_stylePalette.data();
+    return QQuickProxyTheme::palette(type);
 }
 
 QFont QQuickTheme::resolveFont(const QFont &font) const