Fix minimum height of font buttons on non-Windows platforms

python/gui/qgsfontbutton.sip

@@ -45,6 +45,8 @@ class QgsFontButton : QToolButton
  Use ``dialogTitle`` string to define the title to show in the text settings dialog.
 %End
 
+    virtual QSize minimumSizeHint() const;
+
     QgsFontButton::Mode mode() const;
 %Docstring
  Returns the current button mode.

src/gui/qgsfontbutton.cpp

@@ -48,6 +48,16 @@ QgsFontButton::QgsFontButton( QWidget *parent, const QString &dialogTitle )
   setPopupMode( QToolButton::MenuButtonPopup );
 }
 
+QSize QgsFontButton::minimumSizeHint() const
+{
+  //make sure height of button looks good under different platforms
+#ifdef Q_OS_WIN
+  return QToolButton::minimumSizeHint();
+#else
+  return QSize( 120, 28 );
+#endif
+}
+
 void QgsFontButton::showSettingsDialog()
 {
   switch ( mMode )

src/gui/qgsfontbutton.h

@@ -66,6 +66,8 @@ class GUI_EXPORT QgsFontButton : public QToolButton
      */
     QgsFontButton( QWidget *parent SIP_TRANSFERTHIS = nullptr, const QString &dialogTitle = QString() );
 
+    virtual QSize minimumSizeHint() const override;
+
     /**
      * Returns the current button mode.
      * \see setMode()