Finally we can set opacity! Yuuuuu.

app/ApplicationSettings.qml

@@ -28,6 +28,7 @@ Item{
 
     property bool fullscreen: false
 
+    property real windowOpacity: 1.0
     property real ambient_light: 0.2
     property real contrast: 0.85
     property real brightness: 0.5
@@ -160,7 +161,8 @@ Item{
             ambient_light: ambient_light,
             fontScalingIndexes: fontScalingIndexes,
             fontIndexes: fontIndexes,
-            frameReflections: _frameReflections
+            frameReflections: _frameReflections,
+            windowOpacity: windowOpacity
         }
         return JSON.stringify(settings);
     }
@@ -225,6 +227,7 @@ Item{
         fontScalingIndexes = settings.fontScalingIndexes !== undefined ? settings.fontScalingIndexes : fontScalingIndexes
 
         _frameReflections = settings.frameReflections !== undefined ? settings.frameReflections : _frameReflections;
+        windowOpacity = settings.windowOpacity !== undefined ? settings.windowOpacity : windowOpacity;
     }
 
     function loadProfileString(profileString){

app/PreprocessedTerminal.qml

@@ -197,7 +197,7 @@ Item{
         id: blurredSource
         sourceItem: blurredterminal
         recursive: true
-        live: true
+        live: false
 
         smooth: false
         antialiasing: false
@@ -205,13 +205,11 @@ Item{
         Timer{
             id: livetimer
             running: true
-            onTriggered: parent.live = false;
+            onRunningChanged: running ?
+                                  timeManager.onTimeChanged.connect(blurredSource.scheduleUpdate) :
+                                  timeManager.onTimeChanged.disconnect(blurredSource.scheduleUpdate)
 
-            function updateImageHandler(){
+            Component.onCompleted: kterminal.updatedImage.connect(restart);
-                livetimer.restart();
-                blurredSource.live = true;
-            }
-            Component.onCompleted: kterminal.updatedImage.connect(updateImageHandler);
         }
     }
     ShaderEffectSource{
@@ -219,6 +217,7 @@ Item{
         sourceItem: blurredterminal
         sourceRect: frame.sourceRect
         format: ShaderEffectSource.Alpha
+        hideSource: true
     }
     ShaderEffect {
         id: blurredterminal

app/SettingsGeneralTab.qml

@@ -89,6 +89,11 @@ Tab{
                     onValueChanged: shadersettings.ambient_light = value;
                     value: shadersettings.ambient_light
                 }
+                Text{ text: qsTr("Opacity") }
+                SimpleSlider{
+                    onValueChanged: shadersettings.windowOpacity = value
+                    value: shadersettings.windowOpacity
+                }
             }
         }
         GroupBox{

app/SettingsWindow.qml

@@ -28,7 +28,7 @@ Window {
     id: settings_window
     title: qsTr("Settings")
     width: 640
-    height: 420
+    height: 450
 
     property int tabmargins: 15
 

app/main.qml

@@ -36,6 +36,8 @@ ApplicationWindow{
     property bool fullscreen: shadersettings.fullscreen
     onFullscreenChanged: visibility = (fullscreen ? Window.FullScreen : Window.Windowed)
 
+    flags: Qt.WA_TranslucentBackground
+    color: "#00000000"
     title: qsTr("cool-old-term")
 
     Action {
@@ -128,6 +130,7 @@ ApplicationWindow{
         scale: 1.0 / shadersettings.window_scaling
         smooth: false
         antialiasing: false
+        opacity: shadersettings.windowOpacity * 0.3 + 0.7
 
         Loader{
             id: frame