Fix saving/restoring window position for maximized windows

Save both the normal window geometry and its maximized position instead
of saving just its current position. This fixes restoring geometry of
the maximized windows as previously they were always restored on the
primary monitor, as their original position was lost.

Use the native {Get,Set}WindowPlacement() functions for a MSW-specific
wxTLWGeometry implementation to achieve this.

Closes #16335.

include/wx/msw/private/tlwgeom.h

@@ -0,0 +1,126 @@
+///////////////////////////////////////////////////////////////////////////////
+// Name:        wx/msw/private/tlwgeom.h
+// Purpose:     wxMSW-specific wxTLWGeometry class.
+// Author:      Vadim Zeitlin
+// Created:     2018-04-29
+// Copyright:   (c) 2018 Vadim Zeitlin <vadim@wxwidgets.org>
+// Licence:     wxWindows licence
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef _WX_MSW_PRIVATE_TLWGEOM_H_
+#define _WX_MSW_PRIVATE_TLWGEOM_H_
+
+#include "wx/log.h"
+
+#include "wx/msw/private.h"
+
+// names for MSW-specific options
+#define wxPERSIST_TLW_MAX_X "xmax"
+#define wxPERSIST_TLW_MAX_Y "ymax"
+
+class wxTLWGeometry : public wxTLWGeometryBase
+{
+public:
+    wxTLWGeometry()
+    {
+        wxZeroMemory(m_placement);
+        m_placement.length = sizeof(m_placement);
+    }
+
+    virtual bool Save(const Serializer& ser) const wxOVERRIDE
+    {
+        // For compatibility with the existing saved positions/sizes, use the
+        // same keys as the generic version (which was previously used under
+        // MSW too).
+
+        // Normal position and size.
+        const RECT& rc = m_placement.rcNormalPosition;
+        if ( !ser.SaveField(wxPERSIST_TLW_X, rc.left) ||
+             !ser.SaveField(wxPERSIST_TLW_Y, rc.top) )
+            return false;
+
+        if ( !ser.SaveField(wxPERSIST_TLW_W, rc.right - rc.left) ||
+             !ser.SaveField(wxPERSIST_TLW_H, rc.bottom - rc.top) )
+            return false;
+
+        // Maximized/minimized state.
+        UINT show = m_placement.showCmd;
+        if ( !ser.SaveField(wxPERSIST_TLW_MAXIMIZED, show == SW_SHOWMAXIMIZED) )
+            return false;
+
+        if ( !ser.SaveField(wxPERSIST_TLW_ICONIZED, show == SW_SHOWMINIMIZED) )
+            return false;
+
+        // Maximized window position.
+        const POINT pt = m_placement.ptMaxPosition;
+        if ( !ser.SaveField(wxPERSIST_TLW_MAX_X, pt.x) ||
+             !ser.SaveField(wxPERSIST_TLW_MAX_Y, pt.y) )
+            return false;
+
+        // We don't currently save the minimized window position, it doesn't
+        // seem useful for anything and is probably just a left over from
+        // Windows 3.1 days, when icons were positioned on the desktop instead
+        // of being located in the taskbar.
+
+        return true;
+    }
+
+    virtual bool Restore(Serializer& ser) wxOVERRIDE
+    {
+        // Normal position and size.
+        wxRect r;
+        if ( !ser.RestoreField(wxPERSIST_TLW_X, &r.x) ||
+             !ser.RestoreField(wxPERSIST_TLW_Y, &r.y) ||
+             !ser.RestoreField(wxPERSIST_TLW_W, &r.width) ||
+             !ser.RestoreField(wxPERSIST_TLW_H, &r.height) )
+            return false;
+        wxCopyRectToRECT(r, m_placement.rcNormalPosition);
+
+        // Maximized/minimized state.
+        int tmp;
+        UINT& show = m_placement.showCmd;
+        if ( ser.RestoreField(wxPERSIST_TLW_MAXIMIZED, &tmp) && tmp )
+            show = SW_SHOWMAXIMIZED;
+        else if ( ser.RestoreField(wxPERSIST_TLW_ICONIZED, &tmp) && tmp )
+            show = SW_SHOWMINIMIZED;
+        else
+            show = SW_SHOWNORMAL;
+
+        // Maximized window position.
+        if ( ser.RestoreField(wxPERSIST_TLW_MAX_X, &r.x) &&
+             ser.RestoreField(wxPERSIST_TLW_MAX_Y, &r.y) )
+        {
+            m_placement.ptMaxPosition.x = r.x;
+            m_placement.ptMaxPosition.y = r.y;
+        }
+
+        return true;
+    }
+
+    virtual bool GetFrom(const wxTopLevelWindow* tlw) wxOVERRIDE
+    {
+        if ( !::GetWindowPlacement(GetHwndOf(tlw), &m_placement) )
+        {
+            wxLogLastError(wxS("GetWindowPlacement"));
+            return false;
+        }
+
+        return true;
+    }
+
+    virtual bool ApplyTo(wxTopLevelWindow* tlw) wxOVERRIDE
+    {
+        if ( !::SetWindowPlacement(GetHwndOf(tlw), &m_placement) )
+        {
+            wxLogLastError(wxS("SetWindowPlacement"));
+            return false;
+        }
+
+        return true;
+    }
+
+private:
+    WINDOWPLACEMENT m_placement;
+};
+
+#endif // _WX_MSW_PRIVATE_TLWGEOM_H_