Remove deprecated functions

According to Microsoft's documentation, DwmIsCompositionEnabled()
will always return true since Windows 8 [1].
And the DWM composition can't be disabled programmatically since
Windows 8 as well [2].

Since Qt 6 will only support Windows 10, it's apparently these two
functions and their usages are totally useless.

[1] https://docs.microsoft.com/en-us/windows/win32/api/dwmapi/nf-dwmapi-dwmiscompositionenabled
[2] https://docs.microsoft.com/en-us/windows/win32/api/dwmapi/nf-dwmapi-dwmenablecomposition

Change-Id: Ia4040118b719fa8edd8504f9112fbe7e3844e0fa
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>

19 files changed, 18 insertions, 195 deletions

diff --git a/examples/winextras/musicplayer/doc/images/qtwinextras-musicplayer-non-composited.png b/examples/winextras/musicplayer/doc/images/qtwinextras-musicplayer-non-composited.png
deleted file mode 100644
index e0a6afe..0000000
--- a/examples/winextras/musicplayer/doc/images/qtwinextras-musicplayer-non-composited.png
+++ /dev/null
diff --git a/examples/winextras/musicplayer/doc/src/qtwinextras-musicplayer.qdoc b/examples/winextras/musicplayer/doc/src/qtwinextras-musicplayer.qdoc
index 8b8fd57..c27ec0f 100644
--- a/examples/winextras/musicplayer/doc/src/qtwinextras-musicplayer.qdoc
+++ b/examples/winextras/musicplayer/doc/src/qtwinextras-musicplayer.qdoc
@@ -47,38 +47,6 @@
     integrate the window content to the window frame and to make the main window
     and the volume popup translucent and blurred.
 
-    The example applies a different look based on whether composition is enabled
-    or not. When composition is enabled, the main window is made translucent and
-    the window frame is extended to the client area to make the window content
-    integrate seamlessly to the window frame as shown above. When composition
-    is disabled, the colorization color is used as a background color. The
-    following screenshot illustrates how the Music Player example looks when
-    composition is disabled.
-
-    \image qtwinextras-musicplayer-non-composited.png Screenshot of the Music Player example
-
-    The respective code is a combination of extending or resetting the system
-    frame, adjusting the necessary QWidget attributes, and setting an appropriate
-    style sheet to achieve the desired look.
-
-    \snippet musicplayer/musicplayer.cpp 1
-
-    The volume popup does not have a window frame so it is enough to make the
-    popup blurred when composition is enabled. Additionally, a style sheet is
-    applied to get a border that follows the colorization color. Just like for
-    the main window, when composition is disabled, the colorization color is
-    used as a background color.
-
-    \snippet musicplayer/volumebutton.cpp 0
-
-    The example application respects the user's composition settings, reacts
-    to dynamic composition changes, and looks solid regardless of whether
-    composition is enabled or not. It accomplishes this by catching
-    QWinEvent::CompositionChange and QWinEvent::ColorizationChange events
-    and adjusting its looks accordingly.
-
-    \snippet musicplayer/musicplayer.cpp 0
-
     \section1 Jump List
 
     The example creates a custom jump list to provide the user with fast
diff --git a/examples/winextras/musicplayer/musicplayer.cpp b/examples/winextras/musicplayer/musicplayer.cpp
index 4a598d8..0f335d2 100644
--- a/examples/winextras/musicplayer/musicplayer.cpp
+++ b/examples/winextras/musicplayer/musicplayer.cpp
@@ -71,7 +71,6 @@ MusicPlayer::MusicPlayer(QWidget *parent) : QWidget(parent)
     connect(&mediaPlayer, &QMediaPlayer::stateChanged,
             this, &MusicPlayer::updateState);
 
-    stylize();
     setAcceptDrops(true);
 }
 
@@ -131,15 +130,6 @@ void MusicPlayer::seekBackward()
     positionSlider->triggerAction(QSlider::SliderPageStepSub);
 }
 
-//! [0]
-bool MusicPlayer::event(QEvent *event)
-{
-    if (event->type() == QWinEvent::CompositionChange || event->type() == QWinEvent::ColorizationChange)
-        stylize();
-    return QWidget::event(event);
-}
-//! [0]
-
 //! [7]
 void MusicPlayer::showEvent(QShowEvent *event)
 {
@@ -191,26 +181,6 @@ void MusicPlayer::mouseReleaseEvent(QMouseEvent *event)
     event->accept();
 }
 
-//! [1]
-void MusicPlayer::stylize()
-{
-    if (QOperatingSystemVersion::current() < QOperatingSystemVersion::Windows8) {
-        // Set styling options relevant only to Windows 7.
-        if (QtWin::isCompositionEnabled()) {
-            QtWin::extendFrameIntoClientArea(this, -1, -1, -1, -1);
-            setAttribute(Qt::WA_TranslucentBackground, true);
-            setAttribute(Qt::WA_NoSystemBackground, false);
-            setStyleSheet(QStringLiteral("MusicPlayer { background: transparent; }"));
-        } else {
-            QtWin::resetExtendedFrame(this);
-            setAttribute(Qt::WA_TranslucentBackground, false);
-            setStyleSheet(QStringLiteral("MusicPlayer { background: %1; }").arg(QtWin::realColorizationColor().name()));
-        }
-        volumeButton->stylize();
-    }
-}
-//! [1]
-
 void MusicPlayer::updateState(QMediaPlayer::State state)
 {
     if (state == QMediaPlayer::PlayingState) {
diff --git a/examples/winextras/musicplayer/musicplayer.h b/examples/winextras/musicplayer/musicplayer.h
index 49dd25b..58ea8c9 100644
--- a/examples/winextras/musicplayer/musicplayer.h
+++ b/examples/winextras/musicplayer/musicplayer.h
@@ -81,7 +81,6 @@ public slots:
     void seekBackward();
 
 protected:
-    bool event(QEvent *event) override;
     void showEvent(QShowEvent *event) override;
     void dragEnterEvent(QDragEnterEvent *event) override;
     void dropEvent(QDropEvent *event) override;
@@ -90,7 +89,6 @@ protected:
     void mouseReleaseEvent(QMouseEvent *event) override;
 
 private slots:
-    void stylize();
     void updateState(QMediaPlayer::State state);
     void updatePosition(qint64 position);
     void updateDuration(qint64 duration);
diff --git a/examples/winextras/musicplayer/volumebutton.cpp b/examples/winextras/musicplayer/volumebutton.cpp
index 908dba1..9a8cc44 100644
--- a/examples/winextras/musicplayer/volumebutton.cpp
+++ b/examples/winextras/musicplayer/volumebutton.cpp
@@ -83,8 +83,6 @@ VolumeButton::VolumeButton(QWidget *parent) :
     menu = new QMenu(this);
     menu->addAction(action);
     setMenu(menu);
-
-    stylize();
 }
 
 void VolumeButton::increaseVolume()
@@ -106,21 +104,3 @@ void VolumeButton::setVolume(int volume)
 {
     slider->setValue(volume);
 }
-
-//! [0]
-void VolumeButton::stylize()
-{
-    if (QOperatingSystemVersion::current() < QOperatingSystemVersion::Windows8) {
-        // Set styling options relevant only to Windows 7.
-        if (QtWin::isCompositionEnabled()) {
-            QtWin::enableBlurBehindWindow(menu);
-            QString css("QMenu { border: 1px solid %1; border-radius: 2px; background: transparent; }");
-            menu->setStyleSheet(css.arg(QtWin::realColorizationColor().name()));
-        } else {
-            QtWin::disableBlurBehindWindow(menu);
-            QString css("QMenu { border: 1px solid black; background: %1; }");
-            menu->setStyleSheet(css.arg(QtWin::realColorizationColor().name()));
-        }
-    }
-}
-//! [0]
diff --git a/examples/winextras/musicplayer/volumebutton.h b/examples/winextras/musicplayer/volumebutton.h
index c6673d2..cb193dc 100644
--- a/examples/winextras/musicplayer/volumebutton.h
+++ b/examples/winextras/musicplayer/volumebutton.h
@@ -71,7 +71,6 @@ public slots:
     void increaseVolume();
     void descreaseVolume();
     void setVolume(int volume);
-    void stylize();
 
 signals:
     void volumeChanged(int volume);
diff --git a/examples/winextras/quickplayer/doc/images/qtwinextras-quickplayer-non-composited.png b/examples/winextras/quickplayer/doc/images/qtwinextras-quickplayer-non-composited.png
deleted file mode 100644
index 23fdc56..0000000
--- a/examples/winextras/quickplayer/doc/images/qtwinextras-quickplayer-non-composited.png
+++ /dev/null
diff --git a/examples/winextras/quickplayer/doc/src/qtwinextras-quickplayer.qdoc b/examples/winextras/quickplayer/doc/src/qtwinextras-quickplayer.qdoc
index 02fe61c..1492865 100644
--- a/examples/winextras/quickplayer/doc/src/qtwinextras-quickplayer.qdoc
+++ b/examples/winextras/quickplayer/doc/src/qtwinextras-quickplayer.qdoc
@@ -44,23 +44,8 @@
     integrate the window content to the window frame and to make the window
     translucent and blurred.
 
-    The example applies a different look based on whether composition is enabled
-    or not. When composition is enabled, the window is made translucent and
-    the window frame is extended to the client area to make the window content
-    integrate seamlessly to the window frame as shown above.
-
     \snippet quickplayer/qml/main.qml dwm
 
-    When composition is disabled, the colorization color is used as a background
-    color for the window.
-
-    \snippet quickplayer/qml/main.qml color
-
-    The following screenshot illustrates how the Quick Player example looks when
-    composition is disabled.
-
-    \image qtwinextras-quickplayer-non-composited.png Screenshot of the Quick Player example
-
     \section1 Taskbar Overlay and Progress
 
     The example uses Windows Taskbar for two things; it sets an overlay icon
diff --git a/examples/winextras/quickplayer/qml/main.qml b/examples/winextras/quickplayer/qml/main.qml
index ec059e3..ec309a5 100644
--- a/examples/winextras/quickplayer/qml/main.qml
+++ b/examples/winextras/quickplayer/qml/main.qml
@@ -67,7 +67,7 @@ Window {
     minimumHeight: column.implicitHeight + 18
 
     //! [color]
-    color: dwm.compositionEnabled ? "transparent" : dwm.realColorizationColor
+    color: "transparent"
     //! [color]
 
     //! [dwm]
diff --git a/src/imports/winextras/plugins.qmltypes b/src/imports/winextras/plugins.qmltypes
index fff1181..a23a7b1 100644
--- a/src/imports/winextras/plugins.qmltypes
+++ b/src/imports/winextras/plugins.qmltypes
@@ -14,7 +14,6 @@ Module {
         prototype: "QQuickItem"
         exports: ["QtWinExtras/DwmFeatures 1.0"]
         exportMetaObjectRevisions: [0]
-        Property { name: "compositionEnabled"; type: "bool" }
         Property { name: "colorizationColor"; type: "QColor"; isReadonly: true }
         Property { name: "realColorizationColor"; type: "QColor"; isReadonly: true }
         Property { name: "colorizationOpaqueBlend"; type: "bool"; isReadonly: true }
diff --git a/src/imports/winextras/qquickdwmfeatures.cpp b/src/imports/winextras/qquickdwmfeatures.cpp
index 124d957..7baf536 100644
--- a/src/imports/winextras/qquickdwmfeatures.cpp
+++ b/src/imports/winextras/qquickdwmfeatures.cpp
@@ -73,16 +73,6 @@ QQuickDwmFeatures::QQuickDwmFeatures(QQuickItem *parent) :
 
 QQuickDwmFeatures::~QQuickDwmFeatures() = default;
 
-void QQuickDwmFeatures::setCompositionEnabled(bool enabled)
-{
-    QtWin::setCompositionEnabled(enabled);
-}
-
-bool QQuickDwmFeatures::isCompositionEnabled() const
-{
-    return QtWin::isCompositionEnabled();
-}
-
 QColor QQuickDwmFeatures::colorizationColor() const
 {
     return QtWin::colorizationColor();
@@ -325,9 +315,7 @@ bool QQuickDwmFeatures::eventFilter(QObject *object, QEvent *event)
     if (object == window()) {
         if (event->type() == QWinEvent::CompositionChange) {
             d->updateSurfaceFormat();
-            if (static_cast<QWinCompositionChangeEvent *>(event)->isCompositionEnabled())
-                d->updateAll();
-            emit compositionEnabledChanged();
+            d->updateAll();
         } else if (event->type() == QWinEvent::ColorizationChange) {
             emit colorizationColorChanged();
             emit realColorizationColorChanged();
@@ -388,11 +376,10 @@ void QQuickDwmFeaturesPrivate::updateSurfaceFormat()
 {
     Q_Q(QQuickDwmFeatures);
     if (q->window()) {
-        const bool compositionEnabled = q->isCompositionEnabled();
         QSurfaceFormat format = q->window()->format();
-        format.setAlphaBufferSize(compositionEnabled ? 8 : 0);
+        format.setAlphaBufferSize(8);
         q->window()->setFormat(format);
-        q->window()->setColor(compositionEnabled ? QColor(Qt::transparent) : originalSurfaceColor);
+        q->window()->setColor(Qt::transparent);
     }
 }
 
diff --git a/src/imports/winextras/qquickdwmfeatures_p.h b/src/imports/winextras/qquickdwmfeatures_p.h
index 3887d24..c420659 100644
--- a/src/imports/winextras/qquickdwmfeatures_p.h
+++ b/src/imports/winextras/qquickdwmfeatures_p.h
@@ -65,7 +65,6 @@ class QQuickDwmFeaturesPrivate;
 class QQuickDwmFeatures : public QQuickItem
 {
     Q_OBJECT
-    Q_PROPERTY(bool compositionEnabled READ isCompositionEnabled WRITE setCompositionEnabled NOTIFY compositionEnabledChanged)
     Q_PROPERTY(QColor colorizationColor READ colorizationColor NOTIFY colorizationColorChanged)
     Q_PROPERTY(QColor realColorizationColor READ realColorizationColor NOTIFY realColorizationColorChanged)
     Q_PROPERTY(bool colorizationOpaqueBlend READ colorizationOpaqueBlend NOTIFY colorizationOpaqueBlendChanged)
@@ -83,8 +82,6 @@ public:
     explicit QQuickDwmFeatures(QQuickItem *parent = nullptr);
     ~QQuickDwmFeatures();
 
-    void setCompositionEnabled(bool enabled);
-    bool isCompositionEnabled() const;
     QColor colorizationColor() const;
     QColor realColorizationColor() const;
     bool colorizationOpaqueBlend() const;
@@ -116,7 +113,6 @@ public:
 Q_SIGNALS:
     void colorizationColorChanged();
     void realColorizationColorChanged();
-    void compositionEnabledChanged();
     void colorizationOpaqueBlendChanged();
     void topGlassMarginChanged();
     void rightGlassMarginChanged();
diff --git a/src/winextras/qwinevent.cpp b/src/winextras/qwinevent.cpp
index a1e77b4..6d5dbcb 100644
--- a/src/winextras/qwinevent.cpp
+++ b/src/winextras/qwinevent.cpp
@@ -58,8 +58,8 @@ QWinColorizationChangeEvent::QWinColorizationChangeEvent(QRgb color, bool opaque
 
 QWinColorizationChangeEvent::~QWinColorizationChangeEvent() = default;
 
-QWinCompositionChangeEvent::QWinCompositionChangeEvent(bool enabled)
-    : QWinEvent(CompositionChange), enabled(enabled)
+QWinCompositionChangeEvent::QWinCompositionChangeEvent()
+    : QWinEvent(CompositionChange)
 {
 }
 
diff --git a/src/winextras/qwinevent.h b/src/winextras/qwinevent.h
index ad77eb3..f4212fd 100644
--- a/src/winextras/qwinevent.h
+++ b/src/winextras/qwinevent.h
@@ -76,13 +76,8 @@ private:
 class Q_WINEXTRAS_EXPORT QWinCompositionChangeEvent : public QWinEvent
 {
 public:
-    explicit QWinCompositionChangeEvent(bool enabled);
+    explicit QWinCompositionChangeEvent();
     ~QWinCompositionChangeEvent();
-
-    inline bool isCompositionEnabled() const { return enabled; }
-
-private:
-    bool enabled;
 };
 
 QT_END_NAMESPACE
diff --git a/src/winextras/qwineventfilter.cpp b/src/winextras/qwineventfilter.cpp
index 4b88f54..db264b6 100644
--- a/src/winextras/qwineventfilter.cpp
+++ b/src/winextras/qwineventfilter.cpp
@@ -79,7 +79,7 @@ bool QWinEventFilter::nativeEventFilter(const QByteArray &, void *message, long
         event = new QWinColorizationChangeEvent(QRgb(msg->wParam), msg->lParam);
         break;
     case WM_DWMCOMPOSITIONCHANGED :
-        event = new QWinCompositionChangeEvent(QtWin::isCompositionEnabled());
+        event = new QWinCompositionChangeEvent();
         break;
     case WM_THEMECHANGED :
         event = new QWinEvent(QWinEvent::ThemeChange);
diff --git a/src/winextras/qwinfunctions.cpp b/src/winextras/qwinfunctions.cpp
index b0e0ff4..77e5733 100644
--- a/src/winextras/qwinfunctions.cpp
+++ b/src/winextras/qwinfunctions.cpp
@@ -1835,40 +1835,6 @@ void QtWin::disableBlurBehindWindow(QWindow *window)
 /*!
     \since 5.2
 
-    Returns the DWM composition state.
- */
-bool QtWin::isCompositionEnabled()
-{
-    QWinEventFilter::setup();
-
-    BOOL enabled = FALSE;
-    DwmIsCompositionEnabled(&enabled);
-    return enabled;
-}
-
-/*!
-    \since 5.2
-
-    Sets whether the Windows Desktop composition is \a enabled.
-
-    \note The underlying function was declared deprecated as of Windows 8 and
-    takes no effect.
- */
-
-QT_WARNING_PUSH
-QT_WARNING_DISABLE_MSVC(4995)
-void QtWin::setCompositionEnabled(bool enabled)
-{
-    QWinEventFilter::setup();
-
-    UINT compositionEnabled = enabled;
-    DwmEnableComposition(compositionEnabled);
-}
-QT_WARNING_POP
-
-/*!
-    \since 5.2
-
     Returns whether the colorization color is an opaque blend.
  */
 bool QtWin::isCompositionOpaque()
diff --git a/src/winextras/qwinfunctions.h b/src/winextras/qwinfunctions.h
index 8f27a6f..dd17cef 100644
--- a/src/winextras/qwinfunctions.h
+++ b/src/winextras/qwinfunctions.h
@@ -118,8 +118,6 @@ namespace QtWin
     Q_WINEXTRAS_EXPORT void enableBlurBehindWindow(QWindow *window);
     Q_WINEXTRAS_EXPORT void disableBlurBehindWindow(QWindow *window);
 
-    Q_WINEXTRAS_EXPORT bool isCompositionEnabled();
-    Q_WINEXTRAS_EXPORT void setCompositionEnabled(bool enabled);
     Q_WINEXTRAS_EXPORT bool isCompositionOpaque();
 
     Q_WINEXTRAS_EXPORT void setCurrentProcessExplicitAppUserModelID(const QString &id);
diff --git a/tests/manual/dwmfeatures/testwidget.cpp b/tests/manual/dwmfeatures/testwidget.cpp
index e289946..189a44c 100644
--- a/tests/manual/dwmfeatures/testwidget.cpp
+++ b/tests/manual/dwmfeatures/testwidget.cpp
@@ -79,8 +79,7 @@ void TestWidget::changeEvent(QEvent *e)
 bool TestWidget::event(QEvent *e)
 {
     if (e->type() == QWinEvent::CompositionChange) {
-        auto *event = static_cast<QWinCompositionChangeEvent *>(e);
-        qDebug() << "Composition state change: " << event->isCompositionEnabled();
+        qDebug() << "Composition state change.";
     } else if (e->type() == QWinEvent::ThemeChange) {
         qDebug() << "Theme change.";
     }
@@ -123,9 +122,6 @@ void TestWidget::onNonClientAreaRenderingPolicyChanged()
 
 void TestWidget::onGlassMarginsChanged()
 {
-    if (!QtWin::isCompositionEnabled())
-        return;
-
     // what you see here is the only way to force widget to redraw itself
     // so it actually redraws itself without caching and without any glitch
     // but causes flickering :(
diff --git a/tests/manual/quickdwmfeatures/main.qml b/tests/manual/quickdwmfeatures/main.qml
index 3448a1f..0d32c98 100644
--- a/tests/manual/quickdwmfeatures/main.qml
+++ b/tests/manual/quickdwmfeatures/main.qml
@@ -48,21 +48,16 @@ Window {
 
         excludedFromPeek: cbExcludedFromPeek.checked
         peekDisallowed: cbPeekDisallowed.checked
-
-        Component.onCompleted: {
-            cbCompositionEnabled.checked = compositionEnabled
-            compositionEnabled = Qt.binding(function () { return cbCompositionEnabled.checked })
-        }
     }
 
     Rectangle {
         anchors.fill: parent
-        anchors.leftMargin: dwm.compositionEnabled ? dwm.leftGlassMargin : 0
-        anchors.rightMargin: dwm.compositionEnabled ? dwm.rightGlassMargin : 0
-        anchors.topMargin: dwm.compositionEnabled ? dwm.topGlassMargin : 0
-        anchors.bottomMargin: dwm.compositionEnabled ? dwm.bottomGlassMargin : 0
+        anchors.leftMargin: dwm.leftGlassMargin
+        anchors.rightMargin: dwm.rightGlassMargin
+        anchors.topMargin: dwm.topGlassMargin
+        anchors.bottomMargin: dwm.bottomGlassMargin
 
-        visible: !dwm.compositionEnabled || dwm.topGlassMargin > -1 && dwm.leftGlassMargin > -1 && dwm.rightGlassMargin > -1 && dwm.bottomGlassMargin > -1 && !cbBlurBehind.checked
+        visible: dwm.topGlassMargin > -1 && dwm.leftGlassMargin > -1 && dwm.rightGlassMargin > -1 && dwm.bottomGlassMargin > -1 && !cbBlurBehind.checked
     }
 
     GridLayout {
@@ -71,39 +66,30 @@ Window {
         columns: 2
 
         CheckBox {
-            id: cbCompositionEnabled
-            text: "Composition enabled"
-            Layout.columnSpan: 2
-        }
-
-        CheckBox {
             id: cbBlurBehind
             text: "Blur behind enabled"
             Layout.columnSpan: 2
-            enabled: cbCompositionEnabled.checked
         }
 
         Label { text: "Top glass frame margin" }
-        SpinBox { id: sboxTop; minimumValue: -1; maximumValue: 40; value: 0; Layout.alignment: Qt.AlignRight; enabled: cbCompositionEnabled.checked }
+        SpinBox { id: sboxTop; minimumValue: -1; maximumValue: 40; value: 0; Layout.alignment: Qt.AlignRight }
         Label { text: "Right glass frame margin" }
-        SpinBox { id: sboxRight; minimumValue: -1; maximumValue: 40; value: 0; Layout.alignment: Qt.AlignRight; enabled: cbCompositionEnabled.checked }
+        SpinBox { id: sboxRight; minimumValue: -1; maximumValue: 40; value: 0; Layout.alignment: Qt.AlignRight }
         Label { text: "Bottom glass frame margin" }
-        SpinBox { id: sboxBottom; minimumValue: -1; maximumValue: 40; value: 0; Layout.alignment: Qt.AlignRight; enabled: cbCompositionEnabled.checked }
+        SpinBox { id: sboxBottom; minimumValue: -1; maximumValue: 40; value: 0; Layout.alignment: Qt.AlignRight }
         Label { text: "Left glass frame margin" }
-        SpinBox { id: sboxLeft; minimumValue: -1; maximumValue: 40; value: 0; Layout.alignment: Qt.AlignRight; enabled: cbCompositionEnabled.checked }
+        SpinBox { id: sboxLeft; minimumValue: -1; maximumValue: 40; value: 0; Layout.alignment: Qt.AlignRight }
 
         CheckBox {
             id: cbExcludedFromPeek
             text: "Excluded from peek"
             Layout.columnSpan: 2
-            enabled: cbCompositionEnabled.checked
         }
 
         CheckBox {
             id: cbPeekDisallowed
             text: "Peek disallowed"
             Layout.columnSpan: 2
-            enabled: cbCompositionEnabled.checked
         }
 
         Rectangle {