Expose Qt.application.font

This is useful in order to specify font sizes that are some multiple of
the default size (which is almost always guaranteed to be a sensible,
legible size). For example:

Text {
    text: "Large text"
    font.pixelSize: Qt.application.font.pixelSize * 2
}

Other options are:

- "<h3>Large text</h3>" - adds extra space below the text since it's a
HTML element, so not really useful if you want a decent layout.

- Hard-coding a pixel size. Works OK when used in combination with
Qt::AA_EnableHighDpiScaling, and so long as you guess the correct size
that works for each device/display you're targeting. Doesn't work
without setting Qt::AA_EnableHighDpiScaling.

- Using FontMetrics/TextMetrics. Works fine, but is a bit verbose.

- Use an empty Text element. Creates an unnecessary item. Was
superseded by FontMetrics/TextMetrics.

- defaultPixelSize/implicitPixelSize and
defaultPointSize/implicitPointSize. There are already font-related
properties outside of the font grouped property, so this wouldn't be
out of place, but the API is already quite large.

[ChangeLog][QtQuick] Added Qt.application.font property.

Change-Id: I2d0899f2a6b717aab9afcea59f42fbf3715d8406
Task-number: QTBUG-50298
Reviewed-by: Liang Qi <liang.qi@theqtcompany.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/src/quick/util/qquickapplication.cpp b/src/quick/util/qquickapplication.cpp
index a4e2f0eb0e..5c26b23ff7 100644
--- a/src/quick/util/qquickapplication.cpp
+++ b/src/quick/util/qquickapplication.cpp
@@ -90,4 +90,9 @@ Qt::ApplicationState QQuickApplication::state() const
     return QGuiApplication::applicationState();
 }
 
+QFont QQuickApplication::font() const
+{
+    return QGuiApplication::font();
+}
+
 QT_END_NAMESPACE