Introduce QPA API for size grip handling.

- Introduce API to do size grip handling (mouse press
  and move).
- Move Windows code to Windows plugin.
- Move X11 code to XCB plugin and activate it.

Change-Id: I2f61d6ddc1fa07447e668554d41ecc820efca23f
Reviewed-by: Samuel Rødal <samuel.rodal@nokia.com>

src/gui/kernel/qplatformwindow.h

@@ -117,6 +117,8 @@ public:
 
     virtual void windowEvent(QEvent *event);
 
+    virtual bool startSystemResize(const QPoint &pos, Qt::Corner corner);
+
 protected:
     QScopedPointer<QPlatformWindowPrivate> d_ptr;
 private:

src/gui/kernel/qplatformwindow_qpa.cpp

@@ -335,6 +335,23 @@ void QPlatformWindow::windowEvent(QEvent *event)
     Q_UNUSED(event);
 }
 
+/*!
+    Reimplement this method to start a system size grip drag
+    operation if the system supports it and return true to indicate
+    success.
+    It is called from the mouse press event handler of the size grip.
+
+    The default implementation is empty and does nothing with \a pos
+    and \a corner.
+*/
+
+bool QPlatformWindow::startSystemResize(const QPoint &pos, Qt::Corner corner)
+{
+    Q_UNUSED(pos)
+    Q_UNUSED(corner)
+    return false;
+}
+
 /*!
     \class QPlatformWindow
     \since 4.8

src/plugins/platforms/windows/qwindowsmousehandler.cpp

@@ -151,6 +151,16 @@ bool QWindowsMouseHandler::translateMouseEvent(QWindow *window, HWND hwnd,
         return true;
     }
     compressMouseMove(&msg);
+    // Eat mouse move after size grip drag.
+    if (msg.message == WM_MOUSEMOVE) {
+        QWindowsWindow *platformWindow = static_cast<QWindowsWindow *>(window->handle());
+        if (platformWindow->testFlag(QWindowsWindow::SizeGripOperation)) {
+            MSG mouseMsg;
+            while (PeekMessage(&mouseMsg, platformWindow->handle(), WM_MOUSEMOVE, WM_MOUSEMOVE, PM_REMOVE)) ;
+            platformWindow->clearFlag(QWindowsWindow::SizeGripOperation);
+            return true;
+        }
+    }
     const QPoint client(GET_X_LPARAM(msg.lParam), GET_Y_LPARAM(msg.lParam));
     // Enter new window: track to generate leave event.
     if (m_windowUnderMouse != window) {

src/plugins/platforms/windows/qwindowswindow.cpp

@@ -1402,6 +1402,32 @@ void QWindowsWindow::setMouseGrabEnabled_sys(bool grab)
     }
 }
 
+static inline DWORD cornerToWinOrientation(Qt::Corner corner)
+{
+    switch (corner) {
+    case Qt::TopLeftCorner:
+        return 0xf004; // SZ_SIZETOPLEFT;
+    case Qt::TopRightCorner:
+        return 0xf005; // SZ_SIZETOPRIGHT
+    case Qt::BottomLeftCorner:
+        return 0xf007; // SZ_SIZEBOTTOMLEFT
+    case Qt::BottomRightCorner:
+        return 0xf008; // SZ_SIZEBOTTOMRIGHT
+    }
+    return 0;
+}
+
+bool QWindowsWindow::startSystemResize(const QPoint &, Qt::Corner corner)
+{
+    if (!GetSystemMenu(m_data.hwnd, FALSE))
+        return false;
+
+    ReleaseCapture();
+    PostMessage(m_data.hwnd, WM_SYSCOMMAND, cornerToWinOrientation(corner), 0);
+    setFlag(SizeGripOperation);
+    return true;
+}
+
 #ifndef Q_OS_WINCE // maybe available on some SDKs revisit WM_GETMINMAXINFO
 void QWindowsWindow::getSizeHints(MINMAXINFO *mmi) const
 {

src/plugins/platforms/windows/qwindowswindow.h

@@ -122,7 +122,8 @@ public:
         OpenGLSurface = 0x10,
         OpenGLDoubleBuffered = 0x20,
         OpenGlPixelFormatInitialized = 0x40,
-        BlockedByModal = 0x80
+        BlockedByModal = 0x80,
+        SizeGripOperation = 0x100
     };
 
     struct WindowData
@@ -173,6 +174,8 @@ public:
     virtual bool setKeyboardGrabEnabled(bool grab);
     virtual bool setMouseGrabEnabled(bool grab);
 
+    virtual bool startSystemResize(const QPoint &pos, Qt::Corner corner);
+
     Qt::WindowState windowState_sys() const;
     Qt::WindowStates windowStates_sys() const;
 

src/plugins/platforms/xcb/qxcbwindow.cpp

@@ -1670,4 +1670,37 @@ void QXcbWindow::setCursor(xcb_cursor_t cursor)
     xcb_flush(xcb_connection());
 }
 
+#ifdef XCB_USE_XLIB
+
+bool QXcbWindow::startSystemResize(const QPoint &pos, Qt::Corner corner)
+{
+    const xcb_atom_t moveResize = connection()->atom(QXcbAtom::_NET_WM_MOVERESIZE);
+    if (!connection()->wmSupport()->isSupportedByWM(moveResize))
+        return false;
+    XEvent xev;
+    xev.xclient.type = ClientMessage;
+    xev.xclient.message_type = moveResize;
+    Display *display = (Display *)connection()->xlib_display();
+    xev.xclient.display = display;
+    xev.xclient.window = xcb_window();
+    xev.xclient.format = 32;
+    const QPoint globalPos = window()->mapToGlobal(pos);
+    xev.xclient.data.l[0] = globalPos.x();
+    xev.xclient.data.l[1] = globalPos.y();
+    const bool bottom = corner == Qt::BottomRightCorner || corner == Qt::BottomLeftCorner;
+    const bool left = corner == Qt::BottomLeftCorner || corner == Qt::TopLeftCorner;
+    if (bottom)
+        xev.xclient.data.l[2] = left ? 6 : 4; // bottomleft/bottomright
+    else
+        xev.xclient.data.l[2] = left ? 0 : 2; // topleft/topright
+    xev.xclient.data.l[3] = Button1;
+    xev.xclient.data.l[4] = 0;
+    XUngrabPointer(display, CurrentTime);
+    XSendEvent(display, m_screen->root(), False,
+               SubstructureRedirectMask | SubstructureNotifyMask, &xev);
+    return true;
+}
+
+#endif // XCB_USE_XLIB
+
 QT_END_NAMESPACE

src/plugins/platforms/xcb/qxcbwindow.h

@@ -107,6 +107,10 @@ public:
 
     QSurfaceFormat format() const;
 
+#ifdef XCB_USE_XLIB
+    bool startSystemResize(const QPoint &pos, Qt::Corner corner);
+#endif // XCB_USE_XLIB
+
     xcb_window_t xcb_window() const { return m_window; }
     uint depth() const { return m_depth; }
     QImage::Format imageFormat() const { return m_imageFormat; }

src/widgets/widgets/qsizegrip.cpp

@@ -46,6 +46,8 @@
 #include "qapplication.h"
 #include "qevent.h"
 #include "qpainter.h"
+#include "qwindow.h"
+#include <qpa/qplatformwindow.h>
 #include "qstyle.h"
 #include "qstyleoption.h"
 #include "qlayout.h"
@@ -59,23 +61,8 @@
 #include <private/qwidget_p.h>
 #include <QtWidgets/qabstractscrollarea.h>
 
-#ifdef  Q_OS_WIN
-#  include <QtCore/qt_windows.h>
-#  include "private/qapplication_p.h"
-#endif
-
 QT_BEGIN_NAMESPACE
 
-#if defined (Q_OS_WIN)
-#    define SZ_SIZEBOTTOMRIGHT  0xf008
-#    define SZ_SIZEBOTTOMLEFT   0xf007
-#    define SZ_SIZETOPLEFT      0xf004
-#    define SZ_SIZETOPRIGHT     0xf005
-
-HMENU qt_getWindowsSystemMenu(const QWidget *w);
-
-#endif
-
 static QWidget *qt_sizegrip_topLevelWidget(QWidget* w)
 {
     while (w && !w->isWindow() && w->windowType() != Qt::SubWindow)
@@ -87,6 +74,7 @@ class QSizeGripPrivate : public QWidgetPrivate
 {
     Q_DECLARE_PUBLIC(QSizeGrip)
 public:
+    QSizeGripPrivate();
     void init();
     QPoint p;
     QRect r;
@@ -143,8 +131,19 @@ public:
         if (showSizeGrip)
             q->setVisible(true);
     }
+
+    bool m_platformSizeGrip;
 };
 
+QSizeGripPrivate::QSizeGripPrivate()
+    : dxMax(0)
+    , dyMax(0)
+    , gotMousePress(false)
+    , tlw(0)
+    , m_platformSizeGrip(false)
+{
+}
+
 #ifdef Q_WS_MAC
 void QSizeGripPrivate::updateMacSizer(bool hide) const
 {
@@ -226,11 +225,7 @@ QSizeGrip::QSizeGrip(QWidget * parent)
 void QSizeGripPrivate::init()
 {
     Q_Q(QSizeGrip);
-    dxMax = 0;
-    dyMax = 0;
-    tlw = 0;
     m_corner = q->isLeftToRight() ? Qt::BottomRightCorner : Qt::BottomLeftCorner;
-    gotMousePress = false;
 
 #if !defined(QT_NO_CURSOR) && !defined(Q_WS_MAC)
     q->setCursor(m_corner == Qt::TopLeftCorner || m_corner == Qt::BottomRightCorner
@@ -284,6 +279,7 @@ void QSizeGrip::paintEvent(QPaintEvent *event)
     resize operation. The mouse press event is passed in the \a event
     parameter.
 */
+
 void QSizeGrip::mousePressEvent(QMouseEvent * e)
 {
     if (e->button() != Qt::LeftButton) {
@@ -297,44 +293,20 @@ void QSizeGrip::mousePressEvent(QMouseEvent * e)
     d->gotMousePress = true;
     d->r = tlw->geometry();
 
-#ifdef Q_WS_X11
-    // Use a native X11 sizegrip for "real" top-level windows if supported.
-    if (tlw->isWindow() && X11->isSupportedByWM(ATOM(_NET_WM_MOVERESIZE))
+    // Does the platform provide size grip support?
+    d->m_platformSizeGrip = false;
+    if (tlw->isWindow()
+        && tlw->windowHandle()
         && !(tlw->windowFlags() & Qt::X11BypassWindowManagerHint)
-        && !tlw->testAttribute(Qt::WA_DontShowOnScreen) && !tlw->hasHeightForWidth()) {
-        XEvent xev;
-        xev.xclient.type = ClientMessage;
-        xev.xclient.message_type = ATOM(_NET_WM_MOVERESIZE);
-        xev.xclient.display = X11->display;
-        xev.xclient.window = tlw->winId();
-        xev.xclient.format = 32;
-        xev.xclient.data.l[0] = e->globalPos().x();
-        xev.xclient.data.l[1] = e->globalPos().y();
-        if (d->atBottom())
-            xev.xclient.data.l[2] = d->atLeft() ? 6 : 4; // bottomleft/bottomright
-        else
-            xev.xclient.data.l[2] = d->atLeft() ? 0 : 2; // topleft/topright
-        xev.xclient.data.l[3] = Button1;
-        xev.xclient.data.l[4] = 0;
-        XUngrabPointer(X11->display, X11->time);
-        XSendEvent(X11->display, QX11Info::appRootWindow(x11Info().screen()), False,
-                   SubstructureRedirectMask | SubstructureNotifyMask, &xev);
-        return;
+        && !tlw->testAttribute(Qt::WA_DontShowOnScreen)
+        && !tlw->hasHeightForWidth()) {
+        QPlatformWindow *platformWindow = tlw->windowHandle()->handle();
+        const QPoint topLevelPos = mapTo(tlw, e->pos());
+        d->m_platformSizeGrip = platformWindow && platformWindow->startSystemResize(topLevelPos, d->m_corner);
     }
-#endif // Q_WS_X11
-#ifdef Q_OS_WIN
-    if (tlw->isWindow() && !tlw->testAttribute(Qt::WA_DontShowOnScreen) && !tlw->hasHeightForWidth()) {
-        uint orientation = 0;
-        if (d->atBottom())
-            orientation = d->atLeft() ? SZ_SIZEBOTTOMLEFT : SZ_SIZEBOTTOMRIGHT;
-        else
-            orientation = d->atLeft() ? SZ_SIZETOPLEFT : SZ_SIZETOPRIGHT;
 
-        ReleaseCapture();
-        PostMessage(QApplicationPrivate::getHWNDForWidget(tlw), WM_SYSCOMMAND, orientation, 0);
+    if (d->m_platformSizeGrip)
         return;
-    }
-#endif // Q_OS_WIN
 
     // Find available desktop/workspace geometry.
     QRect availableGeometry;
@@ -400,32 +372,16 @@ void QSizeGrip::mousePressEvent(QMouseEvent * e)
 */
 void QSizeGrip::mouseMoveEvent(QMouseEvent * e)
 {
-    if (e->buttons() != Qt::LeftButton) {
+    Q_D(QSizeGrip);
+    if (e->buttons() != Qt::LeftButton || d->m_platformSizeGrip) {
         QWidget::mouseMoveEvent(e);
         return;
     }
 
-    Q_D(QSizeGrip);
     QWidget* tlw = qt_sizegrip_topLevelWidget(this);
     if (!d->gotMousePress || tlw->testAttribute(Qt::WA_WState_ConfigPending))
         return;
 
-#ifdef Q_WS_X11
-    if (tlw->isWindow() && X11->isSupportedByWM(ATOM(_NET_WM_MOVERESIZE))
-        && tlw->isTopLevel() && !(tlw->windowFlags() & Qt::X11BypassWindowManagerHint)
-        && !tlw->testAttribute(Qt::WA_DontShowOnScreen) && !tlw->hasHeightForWidth())
-        return;
-#endif
-#ifdef Q_OS_WIN
-    if (tlw->isWindow() && qt_getWindowsSystemMenu(tlw) && !tlw->testAttribute(Qt::WA_DontShowOnScreen) && !tlw->hasHeightForWidth()) {
-        if (const HWND hwnd = QApplicationPrivate::getHWNDForWidget(tlw)) {
-            MSG msg;
-            while (PeekMessage(&msg, hwnd, WM_MOUSEMOVE, WM_MOUSEMOVE, PM_REMOVE)) ;
-            return;
-        }
-    }
-#endif
-
     QPoint np(e->globalPos());
 
     // Don't extend beyond the available geometry; bound to dyMax and dxMax.