effects/overview: Drop "blur background" option

The blur effect is used to improve the contrast. The option was added
thinking "why not? it might be useful." This was perhaps a mistake and
it should have been added with a clear valid usecase in mind.

CCBUG: 457495

src/effects/overview/kcm/overvieweffectkcm.ui

@@ -37,7 +37,21 @@
      </item>
     </widget>
    </item>
-   <item row="3" column="0" colspan="2">
+   <item row="1" column="0">
+    <widget class="QLabel" name="label">
+     <property name="text">
+      <string>Ignore minimized windows:</string>
+     </property>
+    </widget>
+   </item>
+   <item row="1" column="1">
+    <widget class="QCheckBox" name="kcfg_IgnoreMinimized">
+     <property name="text">
+      <string/>
+     </property>
+    </widget>
+   </item>
+   <item row="2" column="0" colspan="2">
     <widget class="KShortcutsEditor" name="shortcutsEditor">
      <property name="sizePolicy">
       <sizepolicy hsizetype="Preferred" vsizetype="Preferred">
@@ -50,30 +64,6 @@
      </property>
     </widget>
    </item>
-   <item row="1" column="0">
-    <widget class="QLabel" name="label_BlurBackground">
-     <property name="text">
-      <string>Blur background:</string>
-     </property>
-    </widget>
-   </item>
-   <item row="1" column="1">
-    <widget class="QCheckBox" name="kcfg_BlurBackground"/>
-   </item>
-   <item row="2" column="1">
-    <widget class="QCheckBox" name="kcfg_IgnoreMinimized">
-     <property name="text">
-      <string/>
-     </property>
-    </widget>
-   </item>
-   <item row="2" column="0">
-    <widget class="QLabel" name="label">
-     <property name="text">
-      <string>Ignore minimized windows:</string>
-     </property>
-    </widget>
-   </item>
   </layout>
  </widget>
  <customwidgets>

src/effects/overview/overviewconfig.kcfg

@@ -17,10 +17,6 @@
             <default>false</default>
         </entry>
 
-        <entry name="BlurBackground" type="Bool">
-            <default>true</default>
-        </entry>
-
         <entry name="BorderActivate" type="IntList" />
         <entry name="TouchBorderActivate" type="IntList" />
     </group>

src/effects/overview/overvieweffect.cpp

@@ -93,7 +93,6 @@ void OverviewEffect::reconfigure(ReconfigureFlags)
     OverviewConfig::self()->read();
     setLayout(OverviewConfig::layoutMode());
     setAnimationDuration(animationTime(300));
-    setBlurBackground(OverviewConfig::blurBackground());
 
     for (const ElectricBorder &border : std::as_const(m_borderActivate)) {
         effects->unreserveElectricBorder(border, this);
@@ -160,19 +159,6 @@ void OverviewEffect::setLayout(int layout)
     }
 }
 
-bool OverviewEffect::blurBackground() const
-{
-    return m_blurBackground;
-}
-
-void OverviewEffect::setBlurBackground(bool blur)
-{
-    if (m_blurBackground != blur) {
-        m_blurBackground = blur;
-        Q_EMIT blurBackgroundChanged();
-    }
-}
-
 qreal OverviewEffect::partialActivationFactor() const
 {
     return m_partialActivationFactor;

src/effects/overview/overvieweffect.h

@@ -17,7 +17,6 @@ class OverviewEffect : public QuickSceneEffect
     Q_PROPERTY(int animationDuration READ animationDuration NOTIFY animationDurationChanged)
     Q_PROPERTY(int layout READ layout NOTIFY layoutChanged)
     Q_PROPERTY(bool ignoreMinimized READ ignoreMinimized NOTIFY ignoreMinimizedChanged)
-    Q_PROPERTY(bool blurBackground READ blurBackground NOTIFY blurBackgroundChanged)
     Q_PROPERTY(qreal partialActivationFactor READ partialActivationFactor NOTIFY partialActivationFactorChanged)
     // More efficient from a property binding pov rather than binding to partialActivationFactor !== 0
     Q_PROPERTY(bool gestureInProgress READ gestureInProgress NOTIFY gestureInProgressChanged)
@@ -41,9 +40,6 @@ public:
     int animationDuration() const;
     void setAnimationDuration(int duration);
 
-    bool blurBackground() const;
-    void setBlurBackground(bool blur);
-
     qreal partialActivationFactor() const;
     void setPartialActivationFactor(qreal factor);
 
@@ -58,7 +54,6 @@ public:
 Q_SIGNALS:
     void animationDurationChanged();
     void layoutChanged();
-    void blurBackgroundChanged();
     void partialActivationFactorChanged();
     void gestureInProgressChanged();
     void ignoreMinimizedChanged();
@@ -89,7 +84,6 @@ private:
     QString m_searchText;
     Status m_status = Status::Inactive;
     qreal m_partialActivationFactor = 0;
-    bool m_blurBackground = false;
     int m_animationDuration = 400;
     int m_layout = 1;
     bool m_gestureInProgress = false;

src/effects/overview/qml/ScreenView.qml

@@ -81,7 +81,7 @@ FocusScope {
         outputName: targetScreen.name
         property real blurRadius: 0
 
-        layer.enabled: effect.blurBackground
+        layer.enabled: true
         layer.effect: FastBlur {
             radius: backgroundItem.blurRadius
         }