Implement setWindowIcon() for Windows.

Platform implementation for QWindow::setWindowIcon() was missing from
Windows platform plugin.

Task-number: QTBUG-27175
Change-Id: I6807d1ded057b7788a9f2fa5b143e212a666029b
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>

2 files changed, 52 insertions, 3 deletions

diff --git a/src/plugins/platforms/windows/qwindowswindow.cpp b/src/plugins/platforms/windows/qwindowswindow.cpp
index f3830eb962..a31b09d2bf 100644
--- a/src/plugins/platforms/windows/qwindowswindow.cpp
+++ b/src/plugins/platforms/windows/qwindowswindow.cpp
@@ -61,6 +61,8 @@
 
 QT_BEGIN_NAMESPACE
 
+Q_GUI_EXPORT HICON qt_pixmapToWinHICON(const QPixmap &);
+
 static QByteArray debugWinStyle(DWORD style)
 {
     QByteArray rc = "0x";
@@ -699,13 +701,15 @@ QWindowsWindow::QWindowsWindow(QWindow *aWindow, const WindowData &data) :
     m_cursor(QWindowsScreen::screenOf(aWindow)->windowsCursor()->standardWindowCursor()),
     m_dropTarget(0),
     m_savedStyle(0),
-    m_format(aWindow->format())
+    m_format(aWindow->format()),
 #ifdef QT_OPENGL_ES_2
-   , m_eglSurface(0)
+    m_eglSurface(0),
 #endif
 #ifdef Q_OS_WINCE
-  , m_previouslyHidden(false)
+    m_previouslyHidden(false),
 #endif
+    m_iconBig(0),
+    m_iconSmall(0)
 {
     if (aWindow->surfaceType() == QWindow::OpenGLSurface)
         setFlag(OpenGLSurface);
@@ -730,6 +734,7 @@ QWindowsWindow::QWindowsWindow(QWindow *aWindow, const WindowData &data) :
 QWindowsWindow::~QWindowsWindow()
 {
     destroyWindow();
+    destroyIcon();
 }
 
 void QWindowsWindow::destroyWindow()
@@ -1754,4 +1759,32 @@ QByteArray QWindowsWindow::debugWindowFlags(Qt::WindowFlags wf)
     return rc;
 }
 
+static HICON createHIcon(const QIcon &icon, int xSize, int ySize)
+{
+    if (!icon.isNull()) {
+        const QPixmap pm = icon.pixmap(icon.actualSize(QSize(xSize, ySize)));
+        if (!pm.isNull())
+            return qt_pixmapToWinHICON(pm);
+    }
+    return 0;
+}
+
+void QWindowsWindow::setWindowIcon(const QIcon &icon)
+{
+    if (m_data.hwnd) {
+        destroyIcon();
+
+        m_iconSmall = createHIcon(icon, GetSystemMetrics(SM_CXSMICON), GetSystemMetrics(SM_CYSMICON));
+        m_iconBig = createHIcon(icon, GetSystemMetrics(SM_CXICON), GetSystemMetrics(SM_CYICON));
+
+        if (m_iconBig) {
+            SendMessage(m_data.hwnd, WM_SETICON, 0 /* ICON_SMALL */, (LPARAM)m_iconSmall);
+            SendMessage(m_data.hwnd, WM_SETICON, 1 /* ICON_BIG */, (LPARAM)m_iconBig);
+        } else {
+            SendMessage(m_data.hwnd, WM_SETICON, 0 /* ICON_SMALL */, (LPARAM)m_iconSmall);
+            SendMessage(m_data.hwnd, WM_SETICON, 1 /* ICON_BIG */, (LPARAM)m_iconSmall);
+        }
+    }
+}
+
 QT_END_NAMESPACE
diff --git a/src/plugins/platforms/windows/qwindowswindow.h b/src/plugins/platforms/windows/qwindowswindow.h
index 3b7666cf32..5d898a2d41 100644
--- a/src/plugins/platforms/windows/qwindowswindow.h
+++ b/src/plugins/platforms/windows/qwindowswindow.h
@@ -238,6 +238,7 @@ public:
 
     void setEnabled(bool enabled);
     bool isEnabled() const;
+    void setWindowIcon(const QIcon &icon);
 
 #ifndef Q_OS_WINCE
     void alertWindow(int durationMs = 0);
@@ -259,6 +260,7 @@ private:
     void unregisterDropSite();
     void handleGeometryChange();
     void handleWindowStateChange(Qt::WindowState state);
+    inline void destroyIcon();
 
     mutable WindowData m_data;
     mutable unsigned m_flags;
@@ -277,6 +279,8 @@ private:
 #ifdef Q_OS_WINCE
     bool m_previouslyHidden;
 #endif
+    HICON m_iconSmall;
+    HICON m_iconBig;
 };
 
 // Conveniences for window frames.
@@ -346,6 +350,18 @@ void QWindowsWindow::setUserDataOf(HWND hwnd, void *ud)
     SetWindowLongPtr(hwnd, GWLP_USERDATA, LONG_PTR(ud));
 }
 
+inline void QWindowsWindow::destroyIcon()
+{
+    if (m_iconBig) {
+        DestroyIcon(m_iconBig);
+        m_iconBig = 0;
+    }
+    if (m_iconSmall) {
+        DestroyIcon(m_iconSmall);
+        m_iconSmall = 0;
+    }
+}
+
 QT_END_NAMESPACE
 
 #endif // QWINDOWSWINDOW_H