Bump the minimum Qt version to 5.2

build-aux/m4/bitcoin_qt.m4

@@ -276,7 +276,7 @@ AC_DEFUN([_BITCOIN_QT_CHECK_QT5],[
       #endif
     ]],
     [[
-      #if QT_VERSION < 0x050000 || QT_VERSION_MAJOR < 5
+      #if QT_VERSION < 0x050200 || QT_VERSION_MAJOR < 5
       choke
       #endif
     ]])],

src/qt/bitcoin.cpp

@@ -570,10 +570,8 @@ int main(int argc, char *argv[])
     Q_INIT_RESOURCE(bitcoin_locale);
 
     BitcoinApplication app(*node, argc, argv);
-#if QT_VERSION > 0x050100
     // Generate high-dpi pixmaps
     QApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);
-#endif
 #if QT_VERSION >= 0x050600
     QGuiApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
 #endif

src/qt/guiutil.cpp

@@ -47,6 +47,7 @@
 #include <QDoubleValidator>
 #include <QFileDialog>
 #include <QFont>
+#include <QFontDatabase>
 #include <QKeyEvent>
 #include <QLineEdit>
 #include <QSettings>
@@ -55,11 +56,6 @@
 #include <QUrlQuery>
 #include <QMouseEvent>
 
-
-#if QT_VERSION >= 0x50200
-#include <QFontDatabase>
-#endif
-
 #if defined(Q_OS_MAC)
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
@@ -82,13 +78,7 @@ QString dateTimeStr(qint64 nTime)
 
 QFont fixedPitchFont()
 {
-#if QT_VERSION >= 0x50200
     return QFontDatabase::systemFont(QFontDatabase::FixedFont);
-#else
-    QFont font("Monospace");
-    font.setStyleHint(QFont::Monospace);
-    return font;
-#endif
 }
 
 // Just some dummy data to generate a convincing random-looking (but consistent) address

src/qt/splashscreen.cpp

@@ -37,9 +37,7 @@ SplashScreen::SplashScreen(interfaces::Node& node, Qt::WindowFlags f, const Netw
 
     float fontFactor            = 1.0;
     float devicePixelRatio      = 1.0;
-#if QT_VERSION > 0x050100
     devicePixelRatio = static_cast<QGuiApplication*>(QCoreApplication::instance())->devicePixelRatio();
-#endif
 
     // define text to place
     QString titleText       = tr(PACKAGE_NAME);
@@ -53,10 +51,8 @@ SplashScreen::SplashScreen(interfaces::Node& node, Qt::WindowFlags f, const Netw
     QSize splashSize(480*devicePixelRatio,320*devicePixelRatio);
     pixmap = QPixmap(splashSize);
 
-#if QT_VERSION > 0x050100
     // change to HiDPI if it makes sense
     pixmap.setDevicePixelRatio(devicePixelRatio);
-#endif
 
     QPainter pixPaint(&pixmap);
     pixPaint.setPen(QColor(100,100,100));