Windows QPA: Improve handling of windows of type Qt::ForeignWindow.

Extract a base class QWindowsBaseWindow from QWindowsWindow that provides
_sys() getters for geometry and margin calculation and implements
QPlatformWindow::geometry()/ frameMargins() to be calculated from the
HWND.

Implement a QWindowsDesktopWindow class directly inheriting
QWindowsBaseWindow which does not allow any manipulation.

Add a thin QWindowsForeignWindow class that wraps a foreign window id and
always returns correct geometry/margin information when queried. Simple
reparenting and manipulation of geometry for child windows is also implemented,
allowing for embedding foreign windows into Qt. When calling other setters on
it, the unimplemented warnings of QPlatformWindow will trigger.

Remove the special casing for foreign/desktop window from QWindowsWindow.
The existing mechanism to cache the geometry/margin values in QWindowsWindow
remains as is.

Rename the existing QWindowsWindow::baseWindowOf() and add checks there.

Task-number: QTBUG-50206
Task-number: QTBUG-41186
Change-Id: Ib57cb87e3981312d32920fe3e49f0b1c4ad516a3
Reviewed-by: Joerg Bornemann <joerg.bornemann@theqtcompany.com>

1 files changed, 89 insertions, 28 deletions

diff --git a/src/plugins/platforms/windows/qwindowswindow.h b/src/plugins/platforms/windows/qwindowswindow.h
index 8497931b9a..999761f3c6 100644
--- a/src/plugins/platforms/windows/qwindowswindow.h
+++ b/src/plugins/platforms/windows/qwindowswindow.h
@@ -118,7 +118,78 @@ struct QWindowsWindowData
                                      const QString &title);
 };
 
-class QWindowsWindow : public QPlatformWindow
+class QWindowsBaseWindow : public QPlatformWindow
+{
+public:
+    explicit QWindowsBaseWindow(QWindow *window) : QPlatformWindow(window) {}
+
+    WId winId() const Q_DECL_OVERRIDE { return WId(handle()); }
+    QRect geometry() const Q_DECL_OVERRIDE { return geometry_sys(); }
+    QMargins frameMargins() const Q_DECL_OVERRIDE { return frameMargins_sys(); }
+    QPoint mapToGlobal(const QPoint &pos) const Q_DECL_OVERRIDE;
+    QPoint mapFromGlobal(const QPoint &pos) const Q_DECL_OVERRIDE;
+
+    using QPlatformWindow::screenForGeometry;
+
+    virtual HWND handle() const = 0;
+    virtual bool isTopLevel() const { return isTopLevel_sys(); }
+
+    unsigned style() const   { return GetWindowLongPtr(handle(), GWL_STYLE); }
+    unsigned exStyle() const { return GetWindowLongPtr(handle(), GWL_EXSTYLE); }
+
+    static QWindowsBaseWindow *baseWindowOf(const QWindow *w);
+    static HWND handleOf(const QWindow *w);
+
+protected:
+    HWND parentHwnd() const { return GetAncestor(handle(), GA_PARENT); }
+    bool isTopLevel_sys() const;
+    QRect frameGeometry_sys() const;
+    QRect geometry_sys() const;
+    void setGeometry_sys(const QRect &rect) const;
+    QMargins frameMargins_sys() const;
+    void hide_sys();
+    void raise_sys();
+    void lower_sys();
+    void setWindowTitle_sys(const QString &title);
+};
+
+class QWindowsDesktopWindow : public QWindowsBaseWindow
+{
+public:
+    explicit QWindowsDesktopWindow(QWindow *window)
+        : QWindowsBaseWindow(window), m_hwnd(GetDesktopWindow()) {}
+
+    QMargins frameMargins() const Q_DECL_OVERRIDE { return QMargins(); }
+    bool isTopLevel() const Q_DECL_OVERRIDE { return true; }
+
+protected:
+     HWND handle() const Q_DECL_OVERRIDE { return m_hwnd; }
+
+private:
+    const HWND m_hwnd;
+};
+
+class QWindowsForeignWindow : public QWindowsBaseWindow
+{
+public:
+    explicit QWindowsForeignWindow(QWindow *window, HWND hwnd);
+
+    void setParent(const QPlatformWindow *window) Q_DECL_OVERRIDE;
+    void setGeometry(const QRect &rect) Q_DECL_OVERRIDE { setGeometry_sys(rect); }
+    void setVisible(bool visible) Q_DECL_OVERRIDE;
+    void raise() Q_DECL_OVERRIDE { raise_sys(); }
+    void lower() Q_DECL_OVERRIDE { lower_sys(); }
+    void setWindowTitle(const QString &title) Q_DECL_OVERRIDE { setWindowTitle_sys(title); }
+
+protected:
+     HWND handle() const Q_DECL_OVERRIDE { return m_hwnd; }
+
+private:
+    const HWND m_hwnd;
+    DWORD m_topLevelStyle;
+};
+
+class QWindowsWindow : public QWindowsBaseWindow
 {
 public:
     enum Flags
@@ -168,14 +239,11 @@ public:
     void setWindowFlags(Qt::WindowFlags flags) Q_DECL_OVERRIDE;
     void setWindowState(Qt::WindowState state) Q_DECL_OVERRIDE;
 
-    HWND handle() const { return m_data.hwnd; }
-
-    WId winId() const Q_DECL_OVERRIDE { return WId(m_data.hwnd); }
     void setParent(const QPlatformWindow *window) Q_DECL_OVERRIDE;
 
     void setWindowTitle(const QString &title) Q_DECL_OVERRIDE;
-    void raise() Q_DECL_OVERRIDE;
-    void lower() Q_DECL_OVERRIDE;
+    void raise() Q_DECL_OVERRIDE { raise_sys(); }
+    void lower() Q_DECL_OVERRIDE { lower_sys(); }
 
     void windowEvent(QEvent *event) Q_DECL_OVERRIDE;
 
@@ -198,14 +266,14 @@ public:
     void setFrameStrutEventsEnabled(bool enabled) Q_DECL_OVERRIDE;
     bool frameStrutEventsEnabled() const Q_DECL_OVERRIDE { return testFlag(FrameStrutEventsEnabled); }
 
+    // QWindowsBaseWindow overrides
+    HWND handle() const Q_DECL_OVERRIDE { return m_data.hwnd; }
+    bool isTopLevel() const Q_DECL_OVERRIDE;
+
     QMargins customMargins() const { return m_data.customMargins; }
     void setCustomMargins(const QMargins &m);
 
-    inline unsigned style() const
-        { return GetWindowLongPtr(m_data.hwnd, GWL_STYLE); }
     void setStyle(unsigned s) const;
-    inline unsigned exStyle() const
-        { return GetWindowLongPtr(m_data.hwnd, GWL_EXSTYLE); }
     void setExStyle(unsigned s) const;
 
     bool handleWmPaint(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam);
@@ -215,8 +283,7 @@ public:
     void handleHidden();
     void handleCompositionSettingsChanged();
 
-    static inline HWND handleOf(const QWindow *w);
-    static inline QWindowsWindow *baseWindowOf(const QWindow *w);
+    static QWindowsWindow *windowsWindowOf(const QWindow *w);
     static QWindow *topLevelOf(QWindow *w);
     static inline void *userDataOf(HWND hwnd);
     static inline void setUserDataOf(HWND hwnd, void *ud);
@@ -262,10 +329,6 @@ public:
     void setHasBorderInFullScreen(bool border);
 private:
     inline void show_sys() const;
-    inline void hide_sys() const;
-    inline void setGeometry_sys(const QRect &rect) const;
-    inline QRect frameGeometry_sys() const;
-    inline QRect geometry_sys() const;
     inline QWindowsWindowData setWindowFlags_sys(Qt::WindowFlags wt, unsigned flags = 0) const;
     inline bool isFullScreen_sys() const;
     inline void setWindowState_sys(Qt::WindowState newState);
@@ -334,19 +397,17 @@ QPoint QWindowsGeometryHint::mapFromGlobal(const QWindow *w, const QPoint &p)
 
 // ---------- QWindowsBaseWindow inline functions.
 
-QWindowsWindow *QWindowsWindow::baseWindowOf(const QWindow *w)
+inline QWindowsWindow *QWindowsWindow::windowsWindowOf(const QWindow *w)
 {
-    if (w)
-        if (QPlatformWindow *pw = w->handle())
-            return static_cast<QWindowsWindow *>(pw);
-    return 0;
-}
-
-HWND QWindowsWindow::handleOf(const QWindow *w)
-{
-    if (const QWindowsWindow *bw = QWindowsWindow::baseWindowOf(w))
-        return bw->handle();
-    return 0;
+    QWindowsWindow *result = Q_NULLPTR;
+    if (w) {
+        const Qt::WindowType type = w->type();
+        if (type != Qt::Desktop && type != Qt::ForeignWindow) {
+            if (QPlatformWindow *pw = w->handle())
+                result = static_cast<QWindowsWindow *>(pw);
+        }
+    }
+    return result;
 }
 
 void *QWindowsWindow::userDataOf(HWND hwnd)