Qt: PostProc setter helper

Ref #11613

(cherry picked from commit cca1c1efc30abed41eba0f3b3091735d3cd2e46d)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/gui/qt4/components/extended_panels.cpp

@@ -698,6 +698,21 @@ void ExtVideo::updateFilterOptions()
     setFilterOption( p_intf, qtu( module ), qtu( option ), i_int, f_float, val);
 }
 
+void ExtVideo::setPostprocessing( struct intf_thread_t *p_intf, int q)
+{
+    const char *psz_name = "postproc";
+
+    if( q == -1 )
+    {
+        ChangeVFiltersString( p_intf, psz_name, false );
+    }
+    else
+    {
+        ChangeVFiltersString( p_intf, psz_name, false );
+        setFilterOption( p_intf, "postproc", "postproc-q", q, -1, QString() );
+    }
+}
+
 /**********************************************************************
  * v4l2 controls
  **********************************************************************/

modules/gui/qt4/components/extended_panels.hpp

@@ -46,6 +46,7 @@ class ExtVideo: public QObject
     friend class ExtendedDialog;
 public:
     ExtVideo( struct intf_thread_t *, QTabWidget * );
+    static void setPostprocessing( struct intf_thread_t *, int q);
 private:
     Ui::ExtVideoWidget ui;
     QSignalMapper* filterMapper;