C / C++ / MFC

21-Sep-06 16:19

Hi,
I am trying to handle the wm_move or wm_moving message to keep a window within a bounding box, I am not able to stop the message from propagating once I'm done with it.

What do I need to do??

I have been messing around with this code.
Code no good, don't use :P

LRESULT CALLBACK WndProcedure(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam)
{
int xMin = 30, xMax = 400;
int yMin = 20, yMax = 400;

int charCount = 0;
int posX=0, posY=0;
int ret = 0;
RECT trect= { 0, 0, 0, 0 };
LPRECT rect =& trect;

switch(Msg)
{

case WM_PAINT:
ret = 0;

case WM_MOVING:
SetWindowPos(hWnd, HWND_TOP, 0, 0, 200, 200, SWP_NOSIZE | SWP_NOMOVE );

GetWindowRect( hWnd, rect );
if ( rect != NULL )
{
if ( rect->left > xMax )
posX = xMax;
if ( rect->left < xMin )
posX = xMin;
if ( rect->top > yMax )
posY = yMax;
if ( rect->top < yMin )
posY = yMin;

if ( posX > 0 || posY > 0 )
SetWindowPos( hWnd, HWND_TOP, 10, 10, 0, 0, SWP_SHOWWINDOW | SWP_NOSIZE );
}

break;

case WM_MOVE:

ret = WM_MOVE;
counter ++;
char buffer2[200];
sprintf( buffer2, "%d MOVE MESSAGES SO FAR.", counter );
charCount = SetWindowText( hWnd, buffer2 );
break;
case WM_DESTROY:
PostQuitMessage(WM_QUIT);
break;
default:
return DefWindowProc(hWnd, Msg, wParam, lParam);
}

return ret;
}

-- modified at 22:39 Thursday 21st September, 2006

Nibu babu thomas21-Sep-06 17:24

21-Sep-06 17:24

beeejay wrote:
What do I need to do??

Well here is a small code snippet which restricts the movement of a child dialog within it's parent dialog, may be this will help you..., this is MFC, you will have to do something similar in SDK.

void CCNonClippingChildDlg::OnMoving( int nSide, LPRECT lpRect ) 
{
    // Store initial co-ordinates, avoid static variables, instead use global or  
    // member variables.
    static RECT rcPreviousCoords = *lpRect;
 
    // Get parent
    CWnd *pParentDlg = GetParent();
 
    if( !pParentWnd )
        return;
 
    // Get parent rect
    CRect crParentRect;
    pParentDlg->GetClientRect( &crParentRect );
    pParentDlg->ClientToScreen( &crParentRect );
 
    // If both left and right coordinates are valid update those coordinates,
    // else reset left and right to previous valid coordinates
    if( lpRect->left <= crParentRect.left || lpRect->right >= crParentRect.right )
    {
        lpRect->left = rcPreviousCoords.left;
        lpRect->right = rcPreviousCoords.right;
    }
    else
    {
        rcPreviousCoords.left = lpRect->left;
        rcPreviousCoords.right = lpRect->right;
    }
 
    // If both top and bottom coordinates are valid update those coordinates,
    // else reset top and bottom to previous valid coordinates
    if( lpRect->top <= crParentRect.top || lpRect->bottom >= crParentRect.bottom )
    {
        lpRect->top = rcPreviousCoords.top;
        lpRect->bottom = rcPreviousCoords.bottom;
    }
    else
    {
        rcPreviousCoords.top = lpRect->top;
        rcPreviousCoords.bottom = lpRect->bottom;
    }
}

I handled the WM_MOVING message.

Nibu thomas
A Developer

Programming tips[^] My site[^]

beeejay21-Sep-06 17:34

21-Sep-06 17:34

Ok i tried somthing similiar but the window is being drawn in my location and then in the location it would be had I not interfered.

How are you calling this within the wndProcedure? Is there a window callback in mfc as there is in win32?

Thanks

Nibu babu thomas21-Sep-06 17:43

21-Sep-06 17:43

beeejay wrote:
Ok i tried somthing similiar but the window is being drawn in my location and then in the location it would be had I not interfered.

It's working fine in MFC.

beeejay wrote:
How are you calling this within the wndProcedure? Is there a window callback in mfc as there is in win32?

In WindowProcyou will have to do something like

LRESULT WindowProc( ... )
{
    switch( message )
    {
        case WM_MOVING:
            OnMoving( ... ); // Pass in required parameters.
    }

    DefWindowProc( ... );
}

In the previous given function you will have to convert functions from MFC to SDK format. Like passing the HWND as the first parameter as required, rest will be ok...

For eg:

::GetParent( hWndChild );

Nibu thomas
A Developer

Programming tips[^] My site[^]

beeejay21-Sep-06 17:56

21-Sep-06 17:56

OK it doesn't look like there is an OnMoving function within the SDK. would your program function the same way if you were just to paste the contents of your method into the WM_MOVING case?

Thanks Alot,
Ben

Nibu babu thomas21-Sep-06 18:23

21-Sep-06 18:23

beeejay wrote:
OK it doesn't look like there is an OnMoving function within the SDK.

Heh, when did I say that Big Grin | :-D

. I was just calling that function when the event WM_MOVING happens, in order to isolate the code.

beeejay wrote:
would your program function the same way if you were just to paste the contents of your method into the WM_MOVING case?

It won't. As I said you will have to convert MFC to SDK.

For eg: GetParent( hWndChild );

Anyway here is the SDK code and don't tell me again it doesn't work...;)

case WM_MOVING:
        {
            LPRECT lpRect = ( LPRECT )lParam;

            static RECT rcPreviousCoords = *lpRect;
            
            // Get parent window
            HWND pParentWnd = ::GetParent( hWnd );
            
            if( !pParentWnd )
                break ;
            
            RECT crParentRect;
            ::GetClientRect( pParentWnd, &crParentRect );
            ::ClientToScreen(pParentWnd, (LPPOINT)&crParentRect);
	    ::ClientToScreen(pParentWnd, ((LPPOINT)&crParentRect)+1);
            
            if( lpRect->left <= crParentRect.left || lpRect->right >= crParentRect.right )
            {
                lpRect->left = rcPreviousCoords.left;
                lpRect->right = rcPreviousCoords.right;
            }
            else
            {
                rcPreviousCoords.left = lpRect->left;
                rcPreviousCoords.right = lpRect->right;
            }
            
            if( lpRect->top <= crParentRect.top || lpRect->bottom >= crParentRect.bottom )
            {
                lpRect->top = rcPreviousCoords.top;
                lpRect->bottom = rcPreviousCoords.bottom;
            }
            else
            {
                rcPreviousCoords.top = lpRect->top;
                rcPreviousCoords.bottom = lpRect->bottom;
            }

            return TRUE;
        }

Nibu thomas
A Developer

Programming tips[^] My site[^]

beeejay21-Sep-06 18:34

21-Sep-06 18:34

Ok I have somthing very similiar, but I am still having the same problem.
The window is drawn twice, once very quickly in my position( and then erased), and then once in position it would be in had i not intervened.

Here is the code for WM_MOVING:

RECT rect;
GetWindowRect( hWnd, &rect );

    if ( rect.right > xMax )
        rect.left = xMax - ( rect.right - rect.left );
    if ( rect.left < xMin )
        rect.left = xMin;
    if ( rect.bottom > yMax )
        rect.top = yMax - ( rect.bottom - rect.top );
    if ( rect.top < yMin )
        rect.top = yMin;

SetWindowPos( hWnd, HWND_TOP, rect.left, rect.top, 0, 0, SWP_SHOWWINDOW | SWP_NOSIZE );

return true;

Thanks alot

Nibu babu thomas21-Sep-06 18:36

21-Sep-06 18:36

beeejay wrote:
SetWindowPos( hWnd, HWND_TOP, rect.left, rect.top, 0, 0, SWP_SHOWWINDOW | SWP_NOSIZE );

Well this is the problem, you don't have to do this...

Why don't you try the code that I gave, and try to see the difference.

Nibu thomas
A Developer

Programming tips[^] My site[^]

beeejay21-Sep-06 18:47

21-Sep-06 18:47

I was missing this little gem LPRECT lpRect = ( LPRECT )lParam;

Thanks alot,

It seems that the rect which GetWindowRect sets doesn't actually get used after my WM_MOVING hanlder is complete.

Nibu babu thomas21-Sep-06 19:03