Merge bitcoin-core/gui#448: Add helper to load font

d54ec27 qt: Add helper to load font (João Barbosa)

Pull request description:

  Originally submitted as bitcoin-core/gui-qml#49.

ACKs for top commit:
  hebasto:
    re-ACK d54ec27
  stratospher:
    Tested ACK d54ec27. Refactoring the code and defining `loadFont()` in `src/qt/guiutil.cpp` reduces redundant imports of the `QFontDatabase` and is a better design.
  shaavan:
    ACK d54ec27

Tree-SHA512: b156bb6ffb08dd57476f383a29bbb0a1108b62794d430debb77252f7d09df1409a7532b09d17d8836d1c2ab7c126a6618231164b9d0def1b8f361a81ef22d107

Author: hebasto

src/qt/bitcoin.cpp

@@ -47,7 +47,6 @@
 
 #include <QApplication>
 #include <QDebug>
-#include <QFontDatabase>
 #include <QLatin1String>
 #include <QLibraryInfo>
 #include <QLocale>
@@ -577,7 +576,7 @@ int GuiMain(int argc, char* argv[])
     QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
 
     BitcoinApplication app;
-    QFontDatabase::addApplicationFont(":/fonts/monospace");
+    GUIUtil::LoadFont(QStringLiteral(":/fonts/monospace"));
 
     /// 2. Parse command-line options. We do this after qt in order to show an error if there are problems parsing these
     // Command-line options take precedence:

src/qt/guiutil.cpp

@@ -493,6 +493,12 @@ bool hasEntryData(const QAbstractItemView *view, int column, int role)
     return !selection.at(0).data(role).toString().isEmpty();
 }
 
+void LoadFont(const QString& file_name)
+{
+    const int id = QFontDatabase::addApplicationFont(file_name);
+    assert(id != -1);
+}
+
 QString getDefaultDataDirectory()
 {
     return PathToQString(GetDefaultDataDir());

src/qt/guiutil.h

@@ -172,6 +172,11 @@ namespace GUIUtil
 
     void setClipboard(const QString& str);
 
+    /**
+     * Loads the font from the file specified by file_name, aborts if it fails.
+     */
+    void LoadFont(const QString& file_name);
+
     /**
      * Determine default data directory for operating system.
      */