office-gobmx/fpicker/source/win32/filepicker/PreviewCtrl.hxx

/*************************************************************************
 *
 *  OpenOffice.org - a multi-platform office productivity suite
 *
 *  $RCSfile: PreviewCtrl.hxx,v $
 *
 *  $Revision: 1.4 $
 *
 *  last change: $Author: rt $ $Date: 2005-09-08 23:39:39 $
 *
 *  The Contents of this file are made available subject to
 *  the terms of GNU Lesser General Public License Version 2.1.
 *
 *
 *    GNU Lesser General Public License Version 2.1
 *    =============================================
 *    Copyright 2005 by Sun Microsystems, Inc.
 *    901 San Antonio Road, Palo Alto, CA 94303, USA
 *
 *    This library is free software; you can redistribute it and/or
 *    modify it under the terms of the GNU Lesser General Public
 *    License version 2.1, as published by the Free Software Foundation.
 *
 *    This library is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *    Lesser General Public License for more details.
 *
 *    You should have received a copy of the GNU Lesser General Public
 *    License along with this library; if not, write to the Free Software
 *    Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 *    MA  02111-1307  USA
 *
 ************************************************************************/

#ifndef _PREVIEWCTRL_HXX_
#define _PREVIEWCTRL_HXX_

//------------------------------------------------------------------------
// includes
//------------------------------------------------------------------------

#ifndef _SAL_TYPES_H_
#include <sal/types.h>
#endif

#ifndef _RTL_USTRING_HXX_
#include <rtl/ustring.hxx>
#endif

#include <comdef.h>

#include <memory>

//---------------------------------------------
// declaration
//---------------------------------------------

class CDimension
{
public:
    CDimension( ) :
        m_cx( 0 ),
        m_cy( 0 )
    {
    }

    CDimension( sal_Int32 cx, sal_Int32 cy ) :
        m_cx( cx ),
        m_cy( cy )
    {
    }

    sal_Int32 m_cx;
    sal_Int32 m_cy;
};

//--------------------------------------------------
// we use OleInitialize here because we are calling
// some Ole functions to realize the picture preview
// and we expect to be called from the main thread
// so that there will be no problem calling
// OleInitialize (the main thread should be an STA)
// When OleInitialize should fail at worst the
// preview doesn't work
//--------------------------------------------------

class CAutoOleInit
{
public:

    // used to communicate ole
    // initialzation failures
    class COleInitException { };

    CAutoOleInit( )
    {
        HRESULT hr = OleInitialize( NULL );
        if ( FAILED( hr ) )
            throw COleInitException( );
    }

    ~CAutoOleInit( )
    {
        OleUninitialize( );
    }
};

//---------------------------------------------
// A simple file preview class to preview some
// common picture formats like *.gif, *jpg, etc.
// This class is not thread-safe and is
// implmented as singleton, because the class
// has only one static member to reconnect
// from callback functions
// we use a singleton-destroyer to get rid off
// the singleton instance, but this happens
// only on shutdown (unloading of the dll) -
// it's a question of taste (other solutions
// are possible)
//---------------------------------------------

class CFilePreview
{
public:
    // to ensure only one instance (singleton)
    static CFilePreview* createInstance(
        HWND aParent,
        POINT ulCorner,
        const CDimension& aSize,
        HINSTANCE hInstance,
        sal_Bool bShow = sal_True,
        sal_Bool bEnabled = sal_True );

    // sets the size of the preview window
    sal_Bool SAL_CALL setSize( const CDimension& aSize );

    // returns the CDimension of the preview
    sal_Bool SAL_CALL getSize( CDimension& theSize ) const;

    // sets the position of the upper left corner
    // of the preview window relative to the
    // upper left corner of the parent window
    sal_Bool SAL_CALL setPos( POINT ulCorner );

    // returns the current position of the preview
    // relative to the upper left corner of the
    // parent window
    sal_Bool SAL_CALL getPos( POINT& ulCorner ) const;

    // enables or disables the preview window
    // bEnable - true the window is enabled and updates its
    // view when update is called
    // bEnable - false the window shows itself in disabled
    // mode and does not update its view when update is
    // called
    void SAL_CALL enable( sal_Bool bEnable );

    // shows the preview window
    // possible values see SHOW_STATE
    sal_Bool SAL_CALL show( sal_Bool bShow );


    // if the preview is shown and enabled
    // preview of the given file will be shown
    // returns true on success or false if an error
    // occured (the file in not there or not accessible etc.)
    virtual sal_Bool SAL_CALL update( const rtl::OUString& aFileName );

protected:
    // clients can create instances only through the static create method
    CFilePreview(
        HWND aParent,
        POINT ulCorner,
        const CDimension& aSize,
        HINSTANCE hInstance,
        sal_Bool bShow = sal_True,
        sal_Bool bEnabled = sal_True );

    // only the singleton destroyer class is allowed to delete the
    // singleton instance of this class
    virtual ~CFilePreview( );

    // we use the stl auto_ptr class as singleton destroyer
    typedef std::auto_ptr< CFilePreview > FILEPREVIEW_SINGLETON_DESTROYER_T;

protected:
    virtual void SAL_CALL onPaint( HWND hWnd, HDC hDC );

    sal_Bool loadFile( const rtl::OUString& aFileName );

private:
    CAutoOleInit m_autoOleInit;
    POINT        m_pt;
    CDimension   m_dim;
    HWND         m_hwnd;
    sal_Bool     m_bEnabled;
    IPicturePtr  m_IPicture;
    ATOM         m_atomPrevWndClass;
    HINSTANCE    m_hInstance;

    static LRESULT CALLBACK WndProc( HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam );

    static CFilePreview* s_FilePreviewInst;
    static FILEPREVIEW_SINGLETON_DESTROYER_T s_SingletonDestroyer;

private:
    friend FILEPREVIEW_SINGLETON_DESTROYER_T;
};


#endif