From 060b3100826f7eab9ba988af31c433e66755ea4e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Gr=C3=A4=C3=9Flin?= <mgraesslin@kde.org>
Date: Fri, 12 Dec 2014 22:12:11 +0100
Subject: [PATCH] [aurorae] Do not update shadow from ::paint

Paint is in the middle of the compositor rendering loop. Updating
the shadow at that point breaks KWin. Thus we delay the update to
the next event cycle. Obviously it would be even better to only
update the shadow if it changed, but that might be too expensive.
---
 clients/aurorae/src/aurorae.cpp | 10 ++++++++--
 clients/aurorae/src/aurorae.h   |  3 +++
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/clients/aurorae/src/aurorae.cpp b/clients/aurorae/src/aurorae.cpp
index 664ee42bda..70b31b0417 100644
--- a/clients/aurorae/src/aurorae.cpp
+++ b/clients/aurorae/src/aurorae.cpp
@@ -511,13 +511,19 @@ void Decoration::paint(QPainter *painter, const QRect &repaintRegion)
                                     m_padding->top(),
                                     m_buffer.width() - m_padding->left() - m_padding->right(),
                                     m_buffer.height() - m_padding->top() - m_padding->bottom()));
-        setShadow(s);
+        m_scheduledShadow = s;
     } else {
-        setShadow(QSharedPointer<KDecoration2::DecorationShadow>());
+        m_scheduledShadow = QSharedPointer<KDecoration2::DecorationShadow>();
     }
+    QMetaObject::invokeMethod(this, "updateShadow", Qt::QueuedConnection);
     painter->drawImage(rect(), m_buffer, r);
 }
 
+void Decoration::updateShadow()
+{
+    setShadow(m_scheduledShadow);
+}
+
 QMouseEvent Decoration::translatedMouseEvent(QMouseEvent *orig)
 {
     if (!m_padding || client().data()->isMaximized()) {
diff --git a/clients/aurorae/src/aurorae.h b/clients/aurorae/src/aurorae.h
index 26296bf94c..ee1896a44c 100644
--- a/clients/aurorae/src/aurorae.h
+++ b/clients/aurorae/src/aurorae.h
@@ -61,6 +61,8 @@ public Q_SLOTS:
     void init() override;
     void installTitleItem(QQuickItem *item);
 
+    void updateShadow();
+
 Q_SIGNALS:
     void configChanged();
 
@@ -92,6 +94,7 @@ private:
     QScopedPointer<QTimer> m_updateTimer;
     QScopedPointer<QOpenGLContext> m_context;
     QScopedPointer<QOffscreenSurface> m_offscreenSurface;
+    QSharedPointer<KDecoration2::DecorationShadow> m_scheduledShadow;
 };
 
 class ThemeFinder : public QObject