From 35e254a8a97f6ab4d65fc8cc66190af60cf75b98 Mon Sep 17 00:00:00 2001
From: Vlad Zahorodnii <vlad.zahorodnii@kde.org>
Date: Mon, 18 Jan 2021 11:20:34 +0200
Subject: [PATCH] effects/lookingglass: Schedule a repaint when window is
 damaged

This is needed to make per-screen rendering work correctly.

BUG: 431652
---
 effects/lookingglass/lookingglass.cpp | 17 +++++++++++++++--
 effects/lookingglass/lookingglass.h   |  3 +++
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/effects/lookingglass/lookingglass.cpp b/effects/lookingglass/lookingglass.cpp
index dbc2c5d45b..5343b7a489 100644
--- a/effects/lookingglass/lookingglass.cpp
+++ b/effects/lookingglass/lookingglass.cpp
@@ -60,6 +60,7 @@ LookingGlassEffect::LookingGlassEffect()
     effects->registerGlobalShortcut(Qt::META + Qt::Key_0, a);
 
     connect(effects, &EffectsHandler::mouseChanged, this, &LookingGlassEffect::slotMouseChanged);
+    connect(effects, &EffectsHandler::windowDamaged, this, &LookingGlassEffect::slotWindowDamaged);
 
     reconfigure(ReconfigureAll);
 }
@@ -161,7 +162,7 @@ void LookingGlassEffect::zoomIn()
         polling = true;
         effects->startMousePolling();
     }
-    effects->addRepaint(cursorPos().x() - radius, cursorPos().y() - radius, 2 * radius, 2 * radius);
+    effects->addRepaint(magnifierArea());
 }
 
 void LookingGlassEffect::zoomOut()
@@ -177,7 +178,12 @@ void LookingGlassEffect::zoomOut()
             m_enabled = false;
         }
     }
-    effects->addRepaint(cursorPos().x() - radius, cursorPos().y() - radius, 2 * radius, 2 * radius);
+    effects->addRepaint(magnifierArea());
+}
+
+QRect LookingGlassEffect::magnifierArea() const
+{
+    return QRect(cursorPos().x() - radius, cursorPos().y() - radius, 2 * radius, 2 * radius);
 }
 
 void LookingGlassEffect::prePaintScreen(ScreenPrePaintData& data, std::chrono::milliseconds presentTime)
@@ -221,6 +227,13 @@ void LookingGlassEffect::slotMouseChanged(const QPoint& pos, const QPoint& old,
     }
 }
 
+void LookingGlassEffect::slotWindowDamaged()
+{
+    if (isActive()) {
+        effects->addRepaint(magnifierArea());
+    }
+}
+
 void LookingGlassEffect::paintScreen(int mask, const QRegion &region, ScreenPaintData &data)
 {
     // Call the next effect.
diff --git a/effects/lookingglass/lookingglass.h b/effects/lookingglass/lookingglass.h
index 3394bf505b..8c16f36439 100644
--- a/effects/lookingglass/lookingglass.h
+++ b/effects/lookingglass/lookingglass.h
@@ -44,6 +44,8 @@ public:
     int initialRadius() const {
         return initialradius;
     }
+    QRect magnifierArea() const;
+
 public Q_SLOTS:
     void toggle();
     void zoomIn();
@@ -51,6 +53,7 @@ public Q_SLOTS:
     void slotMouseChanged(const QPoint& pos, const QPoint& old,
                               Qt::MouseButtons buttons, Qt::MouseButtons oldbuttons,
                               Qt::KeyboardModifiers modifiers, Qt::KeyboardModifiers oldmodifiers);
+    void slotWindowDamaged();
 
 private:
     bool loadData();