From 3af443867f577bc02ae56e81e17f6610af989f6d Mon Sep 17 00:00:00 2001
From: Hugo Pereira Da Costa <hugo.pereira@free.fr>
Date: Mon, 4 Aug 2014 09:56:45 +0200
Subject: [PATCH] added compositing methods

---
 kstyle/breezehelper.cpp | 66 +++++++++++++++++++++++++++++++++++++++--
 kstyle/breezehelper.h   | 39 +++++++++++++++++++++++-
 2 files changed, 102 insertions(+), 3 deletions(-)

diff --git a/kstyle/breezehelper.cpp b/kstyle/breezehelper.cpp
index c288a38b..d21700cf 100644
--- a/kstyle/breezehelper.cpp
+++ b/kstyle/breezehelper.cpp
@@ -25,14 +25,35 @@
 #include "breezemetrics.h"
 
 #include <KColorUtils>
+#include <KWindowSystem>
+
+#include <QGuiApplication>
 #include <QPainter>
 
 namespace Breeze
 {
     //____________________________________________________________________
     Helper::Helper( KSharedConfig::Ptr config ):
-        _config( config )
-    {}
+        _config( config ),
+        _isX11( false )
+    {
+
+        #if HAVE_X11
+
+        // initialize X11 flag
+        _isX11 = QGuiApplication::platformName() == QStringLiteral("xcb");
+
+
+        if( _isX11 )
+        {
+            // create compositing screen
+            const QString atomName( QStringLiteral( "_NET_WM_CM_S%1" ).arg( QX11Info::appScreen() ) );
+            _compositingManagerAtom = createAtom( atomName );
+        }
+
+        #endif
+
+    }
 
     //____________________________________________________________________
     KSharedConfigPtr Helper::config() const
@@ -878,4 +899,45 @@ namespace Breeze
 
     }
 
+    //________________________________________________________________________________________________________
+    bool Helper::compositingActive( void ) const
+    {
+
+        #if HAVE_X11
+        if( isX11() )
+        {
+            // direct call to X
+            xcb_get_selection_owner_cookie_t cookie( xcb_get_selection_owner( QX11Info::connection(), _compositingManagerAtom ) );
+            ScopedPointer<xcb_get_selection_owner_reply_t> reply( xcb_get_selection_owner_reply( QX11Info::connection(), cookie, nullptr ) );
+            return reply && reply->owner;
+
+        }
+        #endif
+
+        // use KWindowSystem
+        return KWindowSystem::compositingActive();
+
+    }
+
+
+    #if HAVE_X11
+
+    //____________________________________________________________________
+    xcb_atom_t Helper::createAtom( const QString& name ) const
+    {
+
+        if( isX11() )
+        {
+
+            xcb_connection_t* connection( QX11Info::connection() );
+            xcb_intern_atom_cookie_t cookie( xcb_intern_atom( connection, false, name.size(), qPrintable( name ) ) );
+            ScopedPointer<xcb_intern_atom_reply_t> reply( xcb_intern_atom_reply( connection, cookie, nullptr) );
+            return reply ? reply->atom:0;
+
+        } else return 0;
+
+    }
+
+    #endif
+
 }
diff --git a/kstyle/breezehelper.h b/kstyle/breezehelper.h
index 04536934..ab773983 100644
--- a/kstyle/breezehelper.h
+++ b/kstyle/breezehelper.h
@@ -29,6 +29,12 @@
 #include <KColorScheme>
 
 #include <QPainterPath>
+#include <QWidget>
+
+#if HAVE_X11
+#include <QX11Info>
+#include <xcb/xcb.h>
+#endif
 
 namespace Breeze
 {
@@ -189,6 +195,28 @@ namespace Breeze
 
         //@}
 
+        //!@name compositing utilities
+        //@{
+
+        //! true if style was compiled for and is running on X11
+        bool isX11() const
+        { return _isX11; }
+
+        //! returns true if compositing is active
+        bool compositingActive( void ) const;
+
+        //! returns true if a given widget supports alpha channel
+        bool hasAlphaChannel( const QWidget* ) const;
+
+        #if HAVE_X11
+
+        //! create xcb atom
+        xcb_atom_t createAtom( const QString& ) const;
+
+        #endif
+
+        //@}
+
         protected:
 
         //! return color key for a given color, properly accounting for invalid colors
@@ -210,7 +238,16 @@ namespace Breeze
         KStatefulBrush _viewNegativeTextBrush;
         //@}
 
-      };
+        bool _isX11;
+
+        #if HAVE_X11
+
+        //! atom used for compositing manager
+        xcb_atom_t _compositingManagerAtom;
+
+        #endif
+
+    };
 
 }