From cc0434d34cb0cc579c2c77714ac9f97be93016e1 Mon Sep 17 00:00:00 2001
From: Xaver Hugl <xaver.hugl@gmail.com>
Date: Tue, 20 Sep 2022 11:25:02 +0200
Subject: [PATCH] effects/blur: use effect-local data instead of window data
 for blur regions

---
 src/effects/blur/blur.cpp        | 18 +++++++-----------
 src/effects/blur/blur.h          |  3 ++-
 src/libkwineffects/kwineffects.h |  1 -
 3 files changed, 9 insertions(+), 13 deletions(-)

diff --git a/src/effects/blur/blur.cpp b/src/effects/blur/blur.cpp
index 53e54950cf..a6626ef601 100644
--- a/src/effects/blur/blur.cpp
+++ b/src/effects/blur/blur.cpp
@@ -277,7 +277,7 @@ void BlurEffect::reconfigure(ReconfigureFlags flags)
     effects->addRepaintFull();
 }
 
-void BlurEffect::updateBlurRegion(EffectWindow *w) const
+void BlurEffect::updateBlurRegion(EffectWindow *w)
 {
     QRegion region;
     bool valid = false;
@@ -312,14 +312,10 @@ void BlurEffect::updateBlurRegion(EffectWindow *w) const
         }
     }
 
-    // If the specified blur region is empty, enable blur for the whole window.
-    if (region.isEmpty() && valid) {
-        // Set the data to a dummy value.
-        // This is needed to be able to distinguish between the value not
-        // being set, and being set to an empty region.
-        w->setData(WindowBlurBehindRole, 1);
+    if (valid) {
+        blurRegions[w] = region;
     } else {
-        w->setData(WindowBlurBehindRole, region);
+        blurRegions.remove(w);
     }
 }
 
@@ -344,6 +340,7 @@ void BlurEffect::slotWindowAdded(EffectWindow *w)
 
 void BlurEffect::slotWindowDeleted(EffectWindow *w)
 {
+    blurRegions.remove(w);
     auto it = windowBlurChangedConnections.find(w);
     if (it == windowBlurChangedConnections.end()) {
         return;
@@ -453,9 +450,8 @@ QRegion BlurEffect::blurRegion(const EffectWindow *w) const
 {
     QRegion region;
 
-    const QVariant value = w->data(WindowBlurBehindRole);
-    if (value.isValid()) {
-        const QRegion appRegion = qvariant_cast<QRegion>(value);
+    if (auto it = blurRegions.find(w); it != blurRegions.end()) {
+        const QRegion &appRegion = *it;
         if (!appRegion.isEmpty()) {
             if (w->decorationHasAlpha() && decorationSupportsBlurBehind(w)) {
                 region = decorationBlurRegion(w);
diff --git a/src/effects/blur/blur.h b/src/effects/blur/blur.h
index 90b908d8bc..989b4fbfe2 100644
--- a/src/effects/blur/blur.h
+++ b/src/effects/blur/blur.h
@@ -74,7 +74,7 @@ private:
     QRegion decorationBlurRegion(const EffectWindow *w) const;
     bool decorationSupportsBlurBehind(const EffectWindow *w) const;
     bool shouldBlur(const EffectWindow *w, int mask, const WindowPaintData &data) const;
-    void updateBlurRegion(EffectWindow *w) const;
+    void updateBlurRegion(EffectWindow *w);
     void doBlur(const QRegion &shape, const QRect &screen, const float opacity, const QMatrix4x4 &screenProjection, bool isDock, QRect windowRect);
     void uploadRegion(QVector2D *&map, const QRegion &region, const int downSampleIterations);
     void uploadGeometry(GLVertexBuffer *vbo, const QRegion &blurRegion, const QRegion &windowRegion);
@@ -123,6 +123,7 @@ private:
     QVector<BlurValuesStruct> blurStrengthValues;
 
     QMap<EffectWindow *, QMetaObject::Connection> windowBlurChangedConnections;
+    QMap<const EffectWindow *, QRegion> blurRegions;
 
     static KWaylandServer::BlurManagerInterface *s_blurManager;
     static QTimer *s_blurManagerRemoveTimer;
diff --git a/src/libkwineffects/kwineffects.h b/src/libkwineffects/kwineffects.h
index ec93e309bc..3f7ef88f10 100644
--- a/src/libkwineffects/kwineffects.h
+++ b/src/libkwineffects/kwineffects.h
@@ -174,7 +174,6 @@ enum DataRole {
     WindowMinimizedGrabRole,
     WindowUnminimizedGrabRole,
     WindowForceBlurRole, ///< For fullscreen effects to enforce blurring of windows,
-    WindowBlurBehindRole, ///< For single windows to blur behind
     WindowForceBackgroundContrastRole, ///< For fullscreen effects to enforce the background contrast,
     WindowBackgroundContrastRole, ///< For single windows to enable Background contrast
 };