gtk3: stop the ever shrinking size of toplevel on every restore

for getting and setting the window state, work on the toplevel m_pWindow. Leave
the "geometry" alone as its for the purpose of the current known size of the
toplevel window contents

Change-Id: Idf701aacf4aed4eefbca1bc1ebebaf38d1c82e27
Reviewed-on: https://gerrit.libreoffice.org/20397
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>
(cherry picked from commit 7242ed0567297c3c5186b4095496fc01448359f4)
diff --git a/vcl/unx/gtk3/gtk3gtkframe.cxx b/vcl/unx/gtk3/gtk3gtkframe.cxx
index 966dc80..576946f 100644
--- a/vcl/unx/gtk3/gtk3gtkframe.cxx
+++ b/vcl/unx/gtk3/gtk3gtkframe.cxx
@@ -1703,6 +1703,28 @@ void GtkSalFrame::SetWindowState( const SalFrameState* pState )
    TriggerPaintEvent();
}

namespace
{
    void GetPosAndSize(GtkWindow *pWindow, long& rX, long &rY, long &rWidth, long &rHeight)
    {
       gint root_x, root_y;
       gtk_window_get_position(GTK_WINDOW(pWindow), &root_x, &root_y);
       rX = root_x;
       rY = root_y;
       gint width, height;
       gtk_window_get_size(GTK_WINDOW(pWindow), &width, &height);
       rWidth = width;
       rHeight = height;
    }

    Rectangle GetPosAndSize(GtkWindow *pWindow)
    {
        long nX, nY, nWidth, nHeight;
        GetPosAndSize(pWindow, nX, nY, nWidth, nHeight);
        return Rectangle(nX, nY, nX + nWidth, nY + nHeight);
    }
}

bool GtkSalFrame::GetWindowState( SalFrameState* pState )
{
    pState->mnState = WINDOWSTATE_STATE_NORMAL;
@@ -1717,10 +1739,8 @@ bool GtkSalFrame::GetWindowState( SalFrameState* pState )
        pState->mnY                 = m_aRestorePosSize.Top();
        pState->mnWidth             = m_aRestorePosSize.GetWidth();
        pState->mnHeight            = m_aRestorePosSize.GetHeight();
        pState->mnMaximizedX        = maGeometry.nX;
        pState->mnMaximizedY        = maGeometry.nY;
        pState->mnMaximizedWidth    = maGeometry.nWidth;
        pState->mnMaximizedHeight   = maGeometry.nHeight;
        GetPosAndSize(GTK_WINDOW(m_pWindow), pState->mnMaximizedX, pState->mnMaximizedY,
                                             pState->mnMaximizedWidth, pState->mnMaximizedWidth);
        pState->mnMask  |= WINDOWSTATE_MASK_MAXIMIZED_X          |
                           WINDOWSTATE_MASK_MAXIMIZED_Y          |
                           WINDOWSTATE_MASK_MAXIMIZED_WIDTH      |
@@ -1728,10 +1748,8 @@ bool GtkSalFrame::GetWindowState( SalFrameState* pState )
    }
    else
    {
        pState->mnX         = maGeometry.nX;
        pState->mnY         = maGeometry.nY;
        pState->mnWidth     = maGeometry.nWidth;
        pState->mnHeight    = maGeometry.nHeight;
        GetPosAndSize(GTK_WINDOW(m_pWindow), pState->mnX, pState->mnY,
                                             pState->mnWidth, pState->mnHeight);
    }
    pState->mnMask  |= WINDOWSTATE_MASK_X            |
                       WINDOWSTATE_MASK_Y            |
@@ -1932,8 +1950,7 @@ void GtkSalFrame::ShowFullScreen( bool bFullScreen, sal_Int32 nScreen )

    if( bFullScreen )
    {
        m_aRestorePosSize = Rectangle( Point( maGeometry.nX, maGeometry.nY ),
                                       Size( maGeometry.nWidth, maGeometry.nHeight ) );
        m_aRestorePosSize = GetPosAndSize(GTK_WINDOW(m_pWindow));
        SetScreen( nScreen, SET_FULLSCREEN );
    }
    else
@@ -2963,9 +2980,7 @@ gboolean GtkSalFrame::signalWindowState( GtkWidget*, GdkEvent* pEvent, gpointer 
    if(   (pEvent->window_state.new_window_state & GDK_WINDOW_STATE_MAXIMIZED) &&
        ! (pThis->m_nState & GDK_WINDOW_STATE_MAXIMIZED) )
    {
        pThis->m_aRestorePosSize =
            Rectangle( Point( pThis->maGeometry.nX, pThis->maGeometry.nY ),
                       Size( pThis->maGeometry.nWidth, pThis->maGeometry.nHeight ) );
        pThis->m_aRestorePosSize = GetPosAndSize(GTK_WINDOW(pThis->m_pWindow));
    }
    pThis->m_nState = pEvent->window_state.new_window_state;