AOO410/main/fpicker/source/win32/filepicker/PreviewCtrl.hxx

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 * 
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
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 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
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#ifndef _PREVIEWCTRL_HXX_
#define _PREVIEWCTRL_HXX_

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

#include <sal/types.h>
#include <rtl/ustring.hxx>

#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