Add helper function: Get DPI scaled icon size (device-dependent)

src/core/utils/misc.cpp

@@ -43,6 +43,7 @@
 #else
 #include <QApplication>
 #include <QDesktopWidget>
+#include <QStyle>
 #endif
 
 #ifdef Q_OS_WIN
@@ -543,3 +544,12 @@ void Utils::Misc::msleep(unsigned long msecs)
 {
     SleeperThread::msleep(msecs);
 }
+
+#ifndef DISABLE_GUI
+QSize Utils::Misc::smallIconSize()
+{
+    // Get DPI scaled icon size (device-dependent), see QT source
+    int s = QApplication::style()->pixelMetric(QStyle::PM_SmallIconSize);
+    return QSize(s, s);
+}
+#endif

src/core/utils/misc.h

@@ -54,6 +54,7 @@ namespace Utils
         void shutdownComputer(ShutdownAction action);
         // Get screen center
         QPoint screenCenter(QWidget *win);
+        QSize smallIconSize();
 #endif
         int pythonVersion();
         QString pythonExecutable();

src/gui/transferlistfilterswidget.cpp

@@ -67,7 +67,7 @@ FiltersBase::FiltersBase(QWidget *parent, TransferListWidget *transferList)
     setUniformItemSizes(true);
     setSpacing(0);
 
-    setIconSize(QSize(16, 16));
+    setIconSize(Utils::Misc::smallIconSize());
 
 #if defined(Q_OS_MAC)
     setAttribute(Qt::WA_MacShowFocusRect, false);