Add invert effect which inverts aka negates desktop's colors.

Shortcut is Ctrl+F6 for now.
  Requires shaders.

svn path=/trunk/KDE/kdebase/workspace/; revision=683162

effects/CMakeLists.txt

@@ -60,6 +60,7 @@ if(OPENGL_FOUND)
     SET(kwin4_effect_builtins_sources ${kwin4_effect_builtins_sources}
         blur.cpp
         explosioneffect.cpp
+        invert.cpp
         magnifier.cpp
         mousemark.cpp
         shadow.cpp
@@ -68,6 +69,7 @@ if(OPENGL_FOUND)
     install( FILES
         blur.desktop
         explosion.desktop
+        invert.desktop
         magnifier.desktop
         mousemark.desktop
         shadow.desktop
@@ -83,6 +85,8 @@ if(OPENGL_FOUND)
         data/blur.vert
         data/blur-render.frag
         data/blur-render.vert
+        data/invert.frag
+        data/invert.vert
         DESTINATION  ${DATA_INSTALL_DIR}/kwin )
 
     # config modules

effects/data/invert.frag

@@ -0,0 +1,18 @@
+uniform sampler2D sceneTex;
+uniform float textureWidth;
+uniform float textureHeight;
+
+
+// Converts pixel coordinates to texture coordinates
+vec2 pix2tex(vec2 pix)
+{
+    return vec2(pix.x / textureWidth, 1.0 - pix.y / textureHeight);
+}
+
+void main()
+{
+    vec3 tex = texture2D(sceneTex, pix2tex(gl_TexCoord[0].xy)).rgb;
+
+    gl_FragColor = vec4(vec3(1.0) - tex, 1.0);
+}
+

effects/data/invert.vert

@@ -0,0 +1,6 @@
+void main()
+{
+    gl_TexCoord[0].xy = gl_Vertex.xy;
+    gl_Position = ftransform();
+}
+

effects/invert.cpp

@@ -0,0 +1,42 @@
+/*****************************************************************
+ KWin - the KDE window manager
+ This file is part of the KDE project.
+
+Copyright (C) 2007 Rivo Laks <rivolaks@hot.ee>
+
+You can Freely distribute this program under the GNU General Public
+License. See the file "COPYING" for the exact licensing terms.
+******************************************************************/
+
+
+#include "invert.h"
+
+#include <kactioncollection.h>
+#include <kaction.h>
+#include <klocale.h>
+
+
+namespace KWin
+{
+
+KWIN_EFFECT( invert, InvertEffect )
+KWIN_EFFECT_SUPPORTED( invert, ShaderEffect::supported() )
+
+
+InvertEffect::InvertEffect() : QObject(), ShaderEffect("invert")
+    {
+    KActionCollection* actionCollection = new KActionCollection( this );
+    KAction* a = (KAction*)actionCollection->addAction( "Invert" );
+    a->setText( i18n("Toggle Invert effect" ));
+    a->setGlobalShortcut(KShortcut(Qt::CTRL + Qt::Key_F6));
+    connect(a, SIGNAL(triggered(bool)), this, SLOT(toggle()));
+    }
+
+void InvertEffect::toggle()
+    {
+    setEnabled( !isEnabled());
+    }
+
+} // namespace
+
+#include "invert.moc"

effects/invert.desktop

@@ -0,0 +1,15 @@
+[Desktop Entry]
+Encoding=UTF-8
+Name=Invert
+
+Type=Service
+ServiceTypes=KWin/Effect
+X-KDE-PluginInfo-Author=Rivo Laks
+X-KDE-PluginInfo-Email=rivolaks@hot.ee
+X-KDE-PluginInfo-Name=kwin4_effect_invert
+X-KDE-PluginInfo-Version=0.1.0
+X-KDE-PluginInfo-Category=Appearance
+X-KDE-PluginInfo-Depends=
+X-KDE-PluginInfo-License=GPL
+X-KDE-PluginInfo-EnabledByDefault=true
+X-KDE-Library=kwin4_effect_builtins

effects/invert.h

@@ -0,0 +1,34 @@
+/*****************************************************************
+ KWin - the KDE window manager
+ This file is part of the KDE project.
+
+Copyright (C) 2007 Rivo Laks <rivolaks@hot.ee>
+
+You can Freely distribute this program under the GNU General Public
+License. See the file "COPYING" for the exact licensing terms.
+******************************************************************/
+
+#ifndef KWIN_INVERT_H
+#define KWIN_INVERT_H
+
+#include <kwinshadereffect.h>
+
+namespace KWin
+{
+
+/**
+ * Inverts desktop's colors
+ **/
+class InvertEffect : public QObject, public ShaderEffect
+    {
+    Q_OBJECT
+    public:
+        InvertEffect();
+
+    public slots:
+        void toggle();
+    };
+
+} // namespace
+
+#endif