Helper effect for KScreen integration

This effect is controlled by KScreen. It fades out all windows when
KScreen requests this and gives feedback to KScreen once all windows are
faded out. This allows KScreen to adjust the screens in a flicker free
way.

REVIEW: 110661
BUG: 319994
FIXED-IN: 4.11

effects/CMakeLists.txt

@@ -112,6 +112,7 @@ endif()
 
 # Common effects
 include( dialogparent/CMakeLists.txt )
+include( kscreen/CMakeLists.txt )
 include( presentwindows/CMakeLists.txt )
 include( screenedge/CMakeLists.txt )
 include( slidingpopups/CMakeLists.txt )

effects/kscreen/CMakeLists.txt

@@ -0,0 +1,14 @@
+#######################################
+# Effect
+
+# Source files
+set( kwin4_effect_builtins_sources ${kwin4_effect_builtins_sources}
+     kscreen/kscreen.cpp
+)
+
+kde4_add_kcfg_files(kwin4_effect_builtins_sources kscreen/kscreenconfig.kcfgc)
+
+# .desktop files
+install( FILES
+         kscreen/kscreen.desktop
+         DESTINATION ${SERVICES_INSTALL_DIR}/kwin )

effects/kscreen/kscreen.cpp

@@ -0,0 +1,191 @@
+/********************************************************************
+ KWin - the KDE window manager
+ This file is part of the KDE project.
+
+ Copyright (C) 2013 Martin Gräßlin <mgraesslin@kde.org>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*********************************************************************/
+// own
+#include "kscreen.h"
+// KConfigSkeleton
+#include "kscreenconfig.h"
+
+/**
+ * How this effect works:
+ *
+ * Effect announces that it is around through property _KDE_KWIN_KSCREEN_SUPPORT on the root window.
+ *
+ * KScreen watches for this property and when it wants to adjust screens, KScreen goes
+ * through the following protocol:
+ * 1. KScreen sets the property value to 1
+ * 2. Effect starts to fade out all windows
+ * 3. When faded out the effect sets property value to 2
+ * 4. KScreen adjusts the screens
+ * 5. KScreen sets property value to 3
+ * 6. Effect starts to fade in all windows again
+ * 7. Effect sets back property value to 0
+ *
+ * The property has type 32 bits cardinal. To test it use:
+ * xprop -root -f _KDE_KWIN_KSCREEN_SUPPORT 32c -set _KDE_KWIN_KSCREEN_SUPPORT 1
+ *
+ * The states are:
+ * 0: normal
+ * 1: fading out
+ * 2: faded out
+ * 3: fading in
+ **/
+
+namespace KWin
+{
+
+KWIN_EFFECT(kscreen, KscreenEffect)
+
+KscreenEffect::KscreenEffect()
+    : Effect()
+    , m_state(StateNormal)
+    , m_atom(effects->announceSupportProperty("_KDE_KWIN_KSCREEN_SUPPORT", this))
+{
+    connect(effects, SIGNAL(propertyNotify(KWin::EffectWindow*,long)), SLOT(propertyNotify(KWin::EffectWindow*,long)));
+    reconfigure(ReconfigureAll);
+}
+
+KscreenEffect::~KscreenEffect()
+{
+}
+
+void KscreenEffect::reconfigure(ReconfigureFlags flags)
+{
+    Q_UNUSED(flags)
+
+    KscreenConfig::self()->readConfig();
+    m_timeLine.setDuration(animationTime<KscreenConfig>(250));
+}
+
+void KscreenEffect::prePaintScreen(ScreenPrePaintData &data, int time)
+{
+    if (m_state == StateFadingIn || m_state == StateFadingOut) {
+        m_timeLine.setCurrentTime(m_timeLine.currentTime() + time);
+        if (m_timeLine.currentValue() >= 1.0) {
+            switchState();
+        }
+    }
+    effects->prePaintScreen(data, time);
+}
+
+void KscreenEffect::postPaintScreen()
+{
+    if (m_state == StateFadingIn || m_state == StateFadingOut) {
+        effects->addRepaintFull();
+    }
+}
+
+void KscreenEffect::prePaintWindow(EffectWindow *w, WindowPrePaintData &data, int time)
+{
+    if (m_state != StateNormal) {
+        data.setTranslucent();
+    }
+    effects->prePaintWindow(w, data, time);
+}
+
+void KscreenEffect::paintWindow(EffectWindow *w, int mask, QRegion region, WindowPaintData &data)
+{
+    switch (m_state) {
+    case StateFadingOut:
+        data.multiplyOpacity(1.0 - m_timeLine.currentValue());
+        break;
+    case StateFadedOut:
+        data.multiplyOpacity(0.0);
+        break;
+    case StateFadingIn:
+        data.multiplyOpacity(m_timeLine.currentValue());
+        break;
+    default:
+        // no adjustment
+        break;
+    }
+    effects->paintWindow(w, mask, region, data);
+}
+
+void KscreenEffect::propertyNotify(EffectWindow *window, long int atom)
+{
+    if (window || atom != m_atom) {
+        return;
+    }
+    QByteArray byteData = effects->readRootProperty(m_atom, XCB_ATOM_CARDINAL, 32);
+    long *data = reinterpret_cast<long *>(byteData.data());
+    if (!data[0]) {
+        // Property was deleted
+        if (m_state != StateNormal) {
+            m_state = StateNormal;
+            effects->addRepaintFull();
+        }
+        return;
+    }
+    if (data[0] == 0) {
+        // normal state - KWin should have switched to it
+        if (m_state != StateNormal) {
+            m_state = StateNormal;
+            effects->addRepaintFull();
+        }
+        return;
+    }
+    if (data[0] == 2) {
+        // faded out state - KWin should have switched to it
+        if (m_state != StateFadedOut) {
+            m_state = StateFadedOut;
+            effects->addRepaintFull();
+        }
+        return;
+    }
+    if (data[0] == 1) {
+        // kscreen wants KWin to fade out all windows
+        m_state = StateFadingOut;
+        m_timeLine.setCurrentTime(0);
+        effects->addRepaintFull();
+        return;
+    }
+    if (data[0] == 3) {
+        // kscreen wants KWin to fade in again
+        m_state = StateFadingIn;
+        m_timeLine.setCurrentTime(0);
+        effects->addRepaintFull();
+        return;
+    }
+    kDebug(1212) << "Incorrect Property state, immediate stop: " << data[0];
+    m_state = StateNormal;
+    effects->addRepaintFull();
+}
+
+void KscreenEffect::switchState()
+{
+    long value = -1l;
+    if (m_state == StateFadingOut) {
+        m_state = StateFadedOut;
+        value = 2l;
+    } else if (m_state == StateFadingIn) {
+        m_state = StateNormal;
+        value = 0l;
+    }
+    if (value != -1l) {
+        xcb_change_property(connection(), XCB_PROP_MODE_REPLACE, rootWindow(), m_atom, XCB_ATOM_CARDINAL, 32, 1, &value);
+    }
+}
+
+bool KscreenEffect::isActive() const
+{
+    return m_state != StateNormal;
+}
+
+} // namespace KWin

effects/kscreen/kscreen.desktop

@@ -0,0 +1,19 @@
+[Desktop Entry]
+Name=Kscreen
+Icon=preferences-system-windows-effect-kscreen
+Comment=Helper Effect for KScreen
+
+Type=Service
+X-KDE-ServiceTypes=KWin/Effect
+X-KDE-PluginInfo-Author=Martin Gräßlin
+X-KDE-PluginInfo-Email=mgraesslin@kde.org
+X-KDE-PluginInfo-Name=kwin4_effect_kscreen
+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
+X-KDE-Ordering=99
+X-KWin-Requires-OpenGL=false
+X-KWin-Requires-Shaders=false

effects/kscreen/kscreen.h

@@ -0,0 +1,64 @@
+/********************************************************************
+ KWin - the KDE window manager
+ This file is part of the KDE project.
+
+ Copyright (C) 2013 Martin Gräßlin <mgraesslin@kde.org>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*********************************************************************/
+#ifndef KWIN_KSCREEN_H
+#define KWIN_KSCREEN_H
+
+#include <kwineffects.h>
+// Qt
+#include <QTimeLine>
+
+namespace KWin
+{
+
+class KscreenEffect : public Effect
+{
+    Q_OBJECT
+
+public:
+    KscreenEffect();
+    virtual ~KscreenEffect();
+
+    virtual void prePaintScreen(ScreenPrePaintData &data, int time);
+    virtual void postPaintScreen();
+    virtual void prePaintWindow(EffectWindow *w, WindowPrePaintData &data, int time);
+    virtual void paintWindow(EffectWindow *w, int mask, QRegion region, WindowPaintData &data);
+
+    void reconfigure(ReconfigureFlags flags);
+    virtual bool isActive() const;
+
+private Q_SLOTS:
+    void propertyNotify(KWin::EffectWindow *window, long atom);
+
+private:
+    void switchState();
+    enum FadeOutState {
+        StateNormal,
+        StateFadingOut,
+        StateFadedOut,
+        StateFadingIn
+    };
+    QTimeLine m_timeLine;
+    FadeOutState m_state;
+    xcb_atom_t m_atom;
+};
+
+
+} // namespace KWin
+#endif // KWIN_KSCREEN_H

effects/kscreen/kscreen.kcfg

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<kcfg xmlns="http://www.kde.org/standards/kcfg/1.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://www.kde.org/standards/kcfg/1.0
+    http://www.kde.org/standards/kcfg/1.0/kcfg.xsd" >
+    <kcfgfile name="kwinrc"/>
+    <group name="Effect-Kscreen">
+        <entry name="Duration" type="Int">
+            <default>0</default>
+        </entry>
+    </group>
+</kcfg>

effects/kscreen/kscreenconfig.kcfgc

@@ -0,0 +1,5 @@
+File=kscreen.kcfg
+ClassName=KscreenConfig
+NameSpace=KWin
+Singleton=true
+Mutators=true