Drawing on transparent window

[ShurikAg]

Hi,

I have this kind of class:

// SplashWnd.cpp : implementation of the CSplashWnd class

//

/////////////////////////////////////////////////////////////////////////////

#include "stdafx.h"

#include "CapturePrevWnd .h"

#include "Resource.h "

#ifdef _DEBUG

#define new DEBUG_NEW

#undef THIS_FILE

static char THIS_FILE[] = __FILE__;

#endif

/////////////////////////////////////////////////////////////////////////////

// CSplashWnd class

CCapturePrevWnd * CCapturePrevWnd ::m_pSplashWnd = NULL;

CCapturePrevWnd ::CCapturePrevW nd()

{

start.SetPoint( 0,0);

end.SetPoint(0, 0);

}

CCapturePrevWnd ::~CCapturePrev Wnd()

{

// Clear the static window pointer.

ASSERT(m_pSplas hWnd == this);

m_pSplashWnd = NULL;

}

BEGIN_MESSAGE_M AP(CCapturePrev Wnd, CWnd)

//{{AFX_MSG_MAP(C SplashWnd)

ON_WM_CREATE()

ON_WM_PAINT()

ON_WM_LBUTTONDO WN()

ON_WM_LBUTTONUP ()

ON_WM_MOUSEMOVE ()

//}}AFX_MSG_MAP

END_MESSAGE_MAP ()

void CCapturePrevWnd ::ShowCaptureSc reen(CWnd* pParentWnd /*= NULL*/)

{

if (m_pSplashWnd != NULL)

return;

// Allocate a new splash screen, and create the window.

m_pSplashWnd = new CCapturePrevWnd ;

if (!m_pSplashWnd->Create(pParent Wnd))

delete m_pSplashWnd;

else m_pSplashWnd->UpdateWindow() ;

}

BOOL CCapturePrevWnd ::Create(CWnd* pParentWnd /*= NULL*/)

{

return CreateEx(0,

AfxRegisterWndC lass(CS_HREDRAW |CS_VREDRAW |CS_DBLCLKS,
AfxGetApp()->LoadStandardCu rsor(IDC_CROSS) ),

NULL, WS_POPUP | WS_VISIBLE | WS_EX_TRANSPARE NT | WS_BORDER |
WS_MAXIMIZE,
0, 0, 0, 0,

pParentWnd->GetSafeHwnd( ), NULL);

}

void CCapturePrevWnd ::HideCaptureSc reen()

{

// Destroy the window, and update the mainframe.

DestroyWindow() ;

AfxGetMainWnd()->UpdateWindow() ;

}

void CCapturePrevWnd ::PostNcDestroy ()

{

// Free the C++ class.

delete this;

}

int CCapturePrevWnd ::OnCreate(LPCR EATESTRUCT lpCreateStruct)

{

if (CWnd::OnCreate (lpCreateStruct ) == -1)

return -1;

// Center the window.

//CenterWindow();

return 0;

}

void CCapturePrevWnd ::OnPaint()

{

CRect selRect = GetSelRect();

if(!selRect.IsR ectEmpty())

{

CClientDC dc(this);

//dc.SetROP2(R2_N OTXORPEN);

dc.DrawFocusRec t(&selRect);

}

}

void CCapturePrevWnd ::OnLButtonDown (UINT nFlags, CPoint point)

{

start = end = point;

Invalidate();

UpdateWindow();

}

void CCapturePrevWnd ::OnMouseMove(U INT nFlags, CPoint point)

{

switch(nFlags)

{

case MK_LBUTTON:

end = point;

Invalidate();

UpdateWindow();

break;

}

}

void CCapturePrevWnd ::OnLButtonUp(U INT nFlags, CPoint point)

{

end = point;

CRect rect = GetSelRect();

if(!rect.IsRect Empty())

{

CBitmap bitmap;

CClientDC dc(NULL);

CDC memDC;

CBitmap* pOldBitmap;

memDC.CreateCom patibleDC(&dc);

bitmap.CreateCo mpatibleBitmap( &dc, rect.Width(),re ct.Height() );

pOldBitmap = memDC.SelectObj ect(&bitmap);

memDC.BitBlt(0, 0, rect.Width()-2,rect.Height()-2, &dc, rect.left+1,
rect.top+1, SRCCOPY);


OpenClipboard() ;

EmptyClipboard( ) ;

SetClipboardDat a (CF_BITMAP, bitmap.GetSafeH andle() ) ;

CloseClipboard () ;

memDC.SelectObj ect(pOldBitmap) ;

bitmap.Detach() ;

}

HideCaptureScre en();

}

CRect CCapturePrevWnd ::GetSelRect()

{

return CRect(min(start .x,end.x), min(start.y,end .y),

max(start.x,end .x), max(start.y,end .y));

}

this class is suppose to give an ability to draw rectangle on the
desktop
(on top of everything).

All works well except: when I'm drawing the rectangle with mouse the
transparent window doesn't remove the old, already drawn, rectangles in
order
to draw a new one with right dimensions.

All rectangles from every redraw are staing on the window.

How do I solve this problem?

[BigBrian]

Sh******@gmail. com wrote:

Hi,

I have this kind of class:

implementation of the CSplashWnd class

What is CSplashWnd? It's not part of the standard.

/////////////////////////////////////////////////////////////////////////////
#include "stdafx.h"

Oh, must be some sort of Windows header.

this class is suppose to give an ability to draw rectangle on the
desktop
(on top of everything).

All works well except: when I'm drawing the rectangle with mouse the
transparent window doesn't remove the old, already drawn, rectangles in
order
to draw a new one with right dimensions.

All rectangles from every redraw are staing on the window.

How do I solve this problem?

By asking in a windows group. This is off topic here.

-Brian