diff --git a/src/MediaFX/qml/effects/LumaMixer.qml b/src/MediaFX/qml/effects/LumaMixer.qml
index 7edce94..4d4b044 100644
--- a/src/MediaFX/qml/effects/LumaMixer.qml
+++ b/src/MediaFX/qml/effects/LumaMixer.qml
@@ -20,6 +20,8 @@ MediaMixer {
     id: root
 
     default required property Item luma
+    property real transitionWidth: root.width
+    readonly property real timeMulTransitionWidthPlusOne: root.time * transitionWidth + 1.0
 
     fragmentShader: "qrc:/shaders/qml/effects/luma.frag.qsb"
     state: "default"
diff --git a/src/MediaFX/qml/effects/luma.frag b/src/MediaFX/qml/effects/luma.frag
index f41e15f..8b78a88 100644
--- a/src/MediaFX/qml/effects/luma.frag
+++ b/src/MediaFX/qml/effects/luma.frag
@@ -19,6 +19,8 @@ layout(std140, binding = 0) uniform buf {
     mat4 qt_Matrix;
     float qt_Opacity;
     float time;
+    float transitionWidth;
+    float timeMulTransitionWidthPlusOne;
 };
 layout(binding = 1) uniform sampler2D source;
 layout(binding = 2) uniform sampler2D dest;
@@ -27,10 +29,19 @@ void main() {
     vec4 sp = texture(source, qt_TexCoord0);
     vec4 dp = texture(dest, qt_TexCoord0);
     vec4 lp = texture(luma, qt_TexCoord0);
-    vec4 m = clamp((lp * time), vec4(0.0), vec4(1.0));
+    
+
+    vec4 m = clamp((lp * vec4(transitionWidth) - vec4(transitionWidth)) + vec4(timeMulTransitionWidthPlusOne), vec4(0.0), vec4(1.0));
+    fragColor = mix(sp, dp, m) * qt_Opacity;
+
+
+/*
+    float m = clamp((lp.r * transitionWidth - transitionWidth) + (timeMulTransitionWidthPlusOne), 0.0, 1.0);
     fragColor = mix(sp, dp, m) * qt_Opacity;
-    fragColor = vec4(lp.rgb, 1.0);
-    fragColor = vec4(mix(sp.rgb, dp.rgb, m.rgb), 1.0) * qt_Opacity;
+*/
+
+    //fragColor = vec4(lp.rgb, 1.0);
+    //fragColor = vec4(mix(sp.rgb, dp.rgb, m.rgb), 1.0) * qt_Opacity;
     //fragColor = vec4(1.0, 0.0, 0.0, 1.0);
 
 /*XXX
diff --git a/tests/qml/MediaMixerHarness.qml b/tests/qml/MediaMixerHarness.qml
deleted file mode 100644
index 5a42047..0000000
--- a/tests/qml/MediaMixerHarness.qml
+++ /dev/null
@@ -1,87 +0,0 @@
-import QtQuick
-import QtQuick.Shapes
-import QtQuick.Layouts
-import QtQuick.Controls
-
-// Invoke using qml tool as "qml MediaMixerHarness.qml -- <fragshader.qsb> [<vertshader.qsb>]
-// qsb is specified relative to MediaMixerHarness.qml
-
-Item {
-    height: 400
-    width: 400
-
-    ColumnLayout {
-        anchors.fill: parent
-
-        MediaMixer {
-            Layout.fillHeight: true
-            Layout.fillWidth: true
-            dest: destItem
-            fragmentShader: Qt.application.arguments.length >= 4 ? Qt.resolvedUrl(Qt.application.arguments[3]) : ""
-            source: sourceItem
-            time: time.value
-            vertexShader: Qt.application.arguments.length >= 5 ? Qt.resolvedUrl(Qt.application.arguments[4]) : ""
-        }
-        Slider {
-            id: time
-
-            Layout.fillWidth: true
-            from: 0
-            to: 1
-            value: 0.5
-        }
-    }
-    Rectangle {
-        id: sourceItem
-
-        anchors.fill: parent
-        color: "lightblue"
-        layer.enabled: true
-        visible: false
-
-        Shape {
-            anchors.fill: parent
-
-            ShapePath {
-                fillColor: "orange"
-                fillRule: ShapePath.WindingFill
-                scale: Qt.size(sourceItem.width / 160, sourceItem.height / 160)
-                strokeColor: "darkgray"
-                strokeWidth: 3
-
-                PathPolyline {
-                    path: [Qt.point(80, 0), Qt.point(130, 160), Qt.point(0, 55), Qt.point(160, 55), Qt.point(30, 160), Qt.point(80, 0),]
-                }
-            }
-        }
-    }
-    Rectangle {
-        id: destItem
-
-        anchors.fill: parent
-        color: "yellow"
-        layer.enabled: true
-        visible: false
-
-        Shape {
-            id: qt
-
-            anchors.fill: parent
-
-            ShapePath {
-                fillColor: "green"
-                scale: Qt.size(destItem.width / 200, destItem.height / 200)
-                strokeColor: "darkGray"
-                strokeWidth: 3
-
-                PathAngleArc {
-                    centerX: 100
-                    centerY: 100
-                    radiusX: 100
-                    radiusY: 100
-                    sweepAngle: 360
-                }
-            }
-        }
-    }
-}
diff --git a/tools/viewer/main.cpp b/tools/viewer/main.cpp
index 16c76ae..c4115dd 100644
--- a/tools/viewer/main.cpp
+++ b/tools/viewer/main.cpp
@@ -47,6 +47,7 @@ int main(int argc, char* argv[])
     QUrl url(args.at(0));
 
     QQuickView quickView(url);
+    quickView.setResizeMode(QQuickView::ResizeMode::SizeRootObjectToView);
     // qCritical() << quickView.errors();
     quickView.show();
 
diff --git a/tools/viewer/qml/MediaMixerHarness.qml b/tools/viewer/qml/MediaMixerHarness.qml
index 5971ca4..a590d0c 100644
--- a/tools/viewer/qml/MediaMixerHarness.qml
+++ b/tools/viewer/qml/MediaMixerHarness.qml
@@ -7,7 +7,7 @@ import MediaFX
 Item {
     id: root
 
-    default property alias mixer: mixerContainer.children
+    default property alias mixer: mixerContainer.data
 
     height: 400
     state: "default"