From 2bb64077e7e41ce65c9d5847ce6f397cc79c57e0 Mon Sep 17 00:00:00 2001
From: Lucas Murray <lmurray@undefinedfire.com>
Date: Tue, 25 Nov 2008 02:58:28 +0000
Subject: [PATCH] Don't allow windows to cast shadows on screens they are not
 on. BUG: 176018

svn path=/trunk/KDE/kdebase/workspace/; revision=888665
---
 effects/shadow.cpp | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/effects/shadow.cpp b/effects/shadow.cpp
index 8eb56d28b7..eb6f526d7c 100644
--- a/effects/shadow.cpp
+++ b/effects/shadow.cpp
@@ -653,6 +653,16 @@ void ShadowEffect::drawShadowQuadXRender( XRenderPicture *picture, QRect rect, f
 
 void ShadowEffect::drawShadow( EffectWindow* window, int mask, QRegion region, const WindowPaintData& data )
     {
+    // Don't allow windows to cast shadows on other displays
+    QRegion clipperGeom;
+    for( int screen = 0; screen < effects->numScreens(); screen++ )
+        {
+        QRect screenGeom = effects->clientArea( ScreenArea, screen, 0 );
+        if( !( window->geometry() & screenGeom ).isNull() )
+            clipperGeom |= screenGeom;
+        }
+    PaintClipper pc( clipperGeom );
+
 #ifdef KWIN_HAVE_OPENGL_COMPOSITING
     if( effects->compositingType() == OpenGLCompositing )
         {