C / C++ / MFC

12-Jan-07 2:52

Hi,

I've created an MDI application in visual C++ 2005.
It has 2 dialog resources.
1 is the main resource where the user does things and the other I open manually so that when the code for the 1st dialog gets to the part in the code it will show a BMP picture.

I've created a classes for both dialogs.
The second dialog class has a function called showPicture().

<br />
void ImageViewer::showPicture()<br />
{<br />
	CPaintDC dc(this); // device context for painting<br />
<br />
	HBITMAP bmpHandle = (HBITMAP)LoadImage(NULL,<br />
		                               "cat.bmp",//strPictureName,<br />
					       IMAGE_BITMAP,<br />
					       0,<br />
					       0,<br />
							 LR_LOADFROMFILE|LR_CREATEDIBSECTION|LR_DEFAULTSIZE);<br />
					       //LR_LOADFROMFILE);<br />
	CBitmap bmpPicture;<br />
	CDC mdcPicture;<br />
	CBitmap *bmpFromHandle = bmpPicture.FromHandle(bmpHandle);<br />
<br />
	CRect rctPicture;<br />
	m_nCam1img.GetWindowRect(&rctPicture);<br />
		<br />
	mdcPicture.CreateCompatibleDC(&dc);<br />
	CBitmap * bmpPrevious = mdcPicture.SelectObject(bmpFromHandle);<br />
	ScreenToClient(&rctPicture);<br />
<br />
	dc.BitBlt(rctPicture.left, rctPicture.top,<br />
		  rctPicture.Width(), rctPicture.Height(),<br />
		  &mdcPicture, 0, 0, SRCCOPY);<br />
<br />
	DeleteObject(bmpHandle);<br />
	<br />
}<br />

I call this function in the 1st dialog's class.

The program compiles but when I run it and the program gets to the call for the showPicture() function and comes to this line:

<br />
CPaintDC dc(this); // device context for painting<br />

it crashes and gives this error:
Debug Assertion Failed!
Program: c:\..\test.exe
File: f:\..\ship\atlmfc\src\mfc\wingdi.cpp
Line: 1090

Press retry to debug application

When I press re-try it goes to this code:

<br />
ASSERT(::IsWindow(pWnd->m_hWnd));<br />

in wingdi.cpp

<br />
CPaintDC::CPaintDC(CWnd* pWnd)<br />
{<br />
	ASSERT_VALID(pWnd);<br />
	ASSERT(::IsWindow(pWnd->m_hWnd));<br />
<br />
	if (!Attach(::BeginPaint(m_hWnd = pWnd->m_hWnd, &m_ps)))<br />
		AfxThrowResourceException();<br />
}<br />

what am i doing wrong?
the showPicture() function works fine if i create a single dialog based application....
how can I load/view a bitmap in an MDI application environment?

thanks,

Kitty5

James R. Twine12-Jan-07 3:11

James R. Twine

12-Jan-07 3:11

   Sounds to me like your showPicture() function is being called before the window has completed its initalization and has been fully created.

   The code at the start of showPicture() should either check for a valid m_hWnd, or the code calling it should check for it before calling that function.

   Peace!

-=- James
Please rate this message - let me know if I helped or not!<HR>If you think it costs a lot to do it right, just wait until you find out how much it costs to do it wrong!
Avoid driving a vehicle taller than you and remember that Professional Driver on Closed Course does not mean your Dumb Ass on a Public Road!
See DeleteFXPFiles

kitty512-Jan-07 3:35

12-Jan-07 3:35

James,

the following is my imageViewer class:

<br />
IMPLEMENT_DYNAMIC(ImageViewer, CDialog)<br />
<br />
ImageViewer::ImageViewer(CWnd* pParent /*=NULL*/)<br />
	: CDialog(ImageViewer::IDD, pParent)<br />
{<br />
}<br />
<br />
ImageViewer::~ImageViewer()<br />
{<br />
}<br />
<br />
void ImageViewer::DoDataExchange(CDataExchange* pDX)<br />
{<br />
	CDialog::DoDataExchange(pDX);<br />
	DDX_Control(pDX, IDC_CAM1_IMG, m_nCam1img);<br />
	DDX_Control(pDX, IDOK, m_ok);<br />
	DDX_Control(pDX, IDCANCEL, m_canc);<br />
}<br />
<br />
<br />
BEGIN_MESSAGE_MAP(ImageViewer, CDialog)<br />
END_MESSAGE_MAP()<br />
<br />
BOOL ImageViewer::OnInitDialog() <br />
{<br />
	CDialog::OnInitDialog();<br />
		<br />
	return TRUE;  // return TRUE unless you set the focus to a control<br />
	              // EXCEPTION: OCX Property Pages should return FALSE<br />
}<br />
<br />
// ImageViewer message handlers<br />
void ImageViewer::showPicture()<br />
{<br />
	CPaintDC dc(this); // device context for painting<br />
<br />
	HBITMAP bmpHandle = (HBITMAP)LoadImage(NULL,<br />
		                               "cat.bmp",//strPictureName,<br />
					       IMAGE_BITMAP,<br />
					       0,<br />
					       0,<br />
							 LR_LOADFROMFILE|LR_CREATEDIBSECTION|LR_DEFAULTSIZE);<br />
					       //LR_LOADFROMFILE);<br />
	CBitmap bmpPicture;<br />
	CDC mdcPicture;<br />
	CBitmap *bmpFromHandle = bmpPicture.FromHandle(bmpHandle);<br />
<br />
	CRect rctPicture;<br />
	m_nCam1img.GetWindowRect(&rctPicture);<br />
		<br />
	mdcPicture.CreateCompatibleDC(&dc);<br />
	CBitmap * bmpPrevious = mdcPicture.SelectObject(bmpFromHandle);<br />
	ScreenToClient(&rctPicture);<br />
<br />
	dc.BitBlt(rctPicture.left, rctPicture.top,<br />
		  rctPicture.Width(), rctPicture.Height(),<br />
		  &mdcPicture, 0, 0, SRCCOPY);<br />
<br />
	DeleteObject(bmpHandle);<br />
	<br />
}<br />

it doesn't have much.
i open the dialog for this class before i call the showPicture() i also have break points right now... so any initialization should be complete by then... or am i just confused?

thanks,

Kitty5

James R. Twine12-Jan-07 6:51

James R. Twine

12-Jan-07 6:51

If this is a modal dialog, you will not have a way to externally call the showPicture() function while the dialog's window is valid.

For example:

ImageViewer dlgIM;
 
dlg.DoModal();  // <-- Window Valid Here, OnInitDialog() Will Get Called
 
dlg.showPicture();  // <-- Window <code>Not</code> Valid Here, Will Be Destroyed Before DoModal() Returns

That only works if you are calling showPicture() from within the dialog's code somewhere either directly from OnInitDialog() or triggered by some kind of event.

Peace!

kitty516-Jan-07 3:25

16-Jan-07 3:25

James,

I set up the dialogs to be modeless.
it's created:

<br />
void CCameraDataGenTxApp::OnImageViewer()<br />
{<br />
	ImageViewer *imgViewDlg;<br />
	imgViewDlg = new ImageViewer();<br />
	imgViewDlg->Create(IDD_IMAGEVIEWER, NULL);<br />
	imgViewDlg->SetWindowPos(NULL, 0, 0, 620, 390, SWP_NOMOVE);<br />
	imgViewDlg->ShowWindow(SW_SHOW);<br />
}<br />

Called:

<br />
BEGIN_MESSAGE_MAP(CCameraDataGenTxApp, CWinApp)<br />
	ON_COMMAND(ID_APP_ABOUT, &CCameraDataGenTxApp::OnAppAbout)<br />
	// Standard file based document commands<br />
	ON_COMMAND(ID_FILE_NEW, &CWinApp::OnFileNew)<br />
	ON_COMMAND(ID_CAMERA, &CCameraDataGenTxApp::OnCamera1Tx)<br />
	ON_COMMAND(ID_IMGVIEWER, &CCameraDataGenTxApp::OnImageViewer)<br />
	ON_COMMAND(ID_FILE_OPEN, &CWinApp::OnFileOpen)<br />
END_MESSAGE_MAP()<br />

that's why i thought that this would work.
what i'm trying to achieve at the end is to have 3 separate window where we can view pictures from 3 separate cameras we collect data from and 1 dialog box that controls the camera....

if I had just a dialog based app my code works. i simply initialize everything in ::OnInitDialog() and then it has a function called ::OnPaint() that I can call showImage()....

It is in an MDI application where everything gets hazy... Cry | :((

since it doesn't have an ::OnPaint() or ::OnInitDialog() function.
Please advice.

thanks,
Kathleen

Kitty5

Hamid_RT12-Jan-07 17:34

12-Jan-07 17:34

When you trace your code line to line did you see a null value of variables

WhiteSky

kitty516-Jan-07 3:33

16-Jan-07 3:33

WhiteSky,

no i do not see a null value of variable because when i come into the showPicture() function the very 1st thing crashes... CPaintDC dc(this);

which gives me an error:

<br />
it crashes and gives this error:<br />
Debug Assertion Failed!<br />
Program: c:\..\test.exe<br />
File: f:\..\ship\atlmfc\src\mfc\wingdi.cpp<br />
Line: 1090<br />
<br />
Press retry to debug application<br />
<br />
When I press re-try it goes to this code:<br />
<br />
ASSERT(::IsWindow(pWnd->m_hWnd));<br />

in wingdi.cpp

<br />
CPaintDC::CPaintDC(CWnd* pWnd)<br />
{<br />
ASSERT_VALID(pWnd);<br />
ASSERT(::IsWindow(pWnd->m_hWnd));<br />
<br />
if (!Attach(::BeginPaint(m_hWnd = pWnd->m_hWnd, &m_ps)))<br />
AfxThrowResourceException();<br />
}<br />

my reply to James' post:
my dialogs are modeless...
that's why i thought that this would work.
what i'm trying to achieve at the end is to have 3 separate window where we can view pictures from 3 separate cameras we collect data from and 1 dialog box that controls the camera....

if I had just a dialog based app my code works. i simply initialize everything in ::OnInitDialog() and then it has a function called ::OnPaint() that I can call showImage()....

It is in an MDI application where everything gets hazy...
since it doesn't have an ::OnPaint() or ::OnInitDialog() function.
Please advice.

thanks,
Kitty

Kitty5

motion detection

ceejeeb12-Jan-07 1:49

ceejeeb

12-Jan-07 1:49

I need to knwo how to compare to bitmaps so as to detect motion. The bitmaps come from a webcam stream and i have managed to grab the frames as needed. I just now need help in comparing these frames for motion.

Rajesh R Subramanian12-Jan-07 2:26

Rajesh R Subramanian

12-Jan-07 2:26

Interesting project. Must be some 2 lines of code, but I can't get it now! Big Grin | :-D

Nobody can give you wiser advice than yourself. - Cicero
ப்ரம்மா

Cool Ju12-Jan-07 2:48

Cool Ju

12-Jan-07 2:48

Hi,

Are the frames captured color? If it is color then image subtraction is time consuming. I would suggest you convert ur color images to monorchrome amd use image subtraction.

Adios,
Cool Ju Cool | :cool:

Dream Ur Destiny

ceejeeb12-Jan-07 4:33

ceejeeb

12-Jan-07 4:33

yes they are in color at the moment. So how do i convert them to monochrome and then how to i do image subtraction?

Cool Ju13-Jan-07 4:12

Cool Ju

13-Jan-07 4:12

Hi,

Google it. This article would be much help to you.

Motion Detection[^]

Adios,
Cool Ju Cool | :cool:

Dream Ur Destiny

Hamid_RT22-May-07 19:23

To check and Create Folder in Win32 API

22-May-07 19:23

See Motion Detection Algorithms[^] does it helpful for you? Smile | :)

WhiteSky

Suresh H12-Jan-07 0:39

Suresh H

12-Jan-07 0:39

Hello all,

I want to check for some folder in C:\ drive if that folder exists by default then no action if that folder does not exits I have to create the folder. For that I have used below code

CFileFind finder; <br />
	CString szPath , szCMD; <br />
	szPath = "c:\\A\\B";<br />
	if(!finder.FindFile(szPath)) <br />
        {  <br />
		szCMD = "mkdir "; <br />
		szCMD += szPath;  <br />
		system((LPCTSTR)szCMD); <br />
	}<br />
<br />

This code properly in MFC application , I want to know how to do it in Win32 API application??

Please help me with this problem.

Thanking you,
Suresh HC.

CPallini12-Jan-07 0:55

CPallini

12-Jan-07 0:55

You may use FindFirstFile API.
Smile | :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

Rajesh R Subramanian12-Jan-07 1:07

Rajesh R Subramanian

12-Jan-07 1:07

#include "shlwapi.h"

TCHAR szDir[20];

_tcscpy( szDir,_T("D:\\MyNewDir\\") );

if(!PathFileExists(szDir))<font color=green>//the directory already exists</font>
   if( CreateDirectory(szDir,NULL) )
         <font color=green>//MessageBox(NULL,_T("Created"),NULL,MB_OK);</font>

PS: You will need to link to shlwapi.lib for using PathFileExists()

Nobody can give you wiser advice than yourself. - Cicero
ப்ரம்மா

Suresh H12-Jan-07 1:50

Suresh H

12-Jan-07 1:50

Thank you guys CPallini , brahmma , WhiteSky , James R. Twine thanks for the examples.

Now I modified the code to as follows

<br />
int ret;<br />
<br />
char buf[ ] = "C:\\A\\B"; <br />
char *lpStr;<br />
lpStr = buf;<br />
ret = PathFileExists(lpStr);<br />
if(ret == 1)<br />
{<br />
   CreateDirectory(lpStr,NULL);    <br />
}

How to link shlwapi.lib file to code ???

I am getting below error

error LNK2001: unresolved external symbol __imp__PathFileExistsA@4
fatal error LNK1120: 1 unresolved externals

Hamid_RT12-Jan-07 2:01

12-Jan-07 2:01

Open property window of your project and include lib file to it(I dont have vs2003 now) but I think its on linker additional path(its first item on right panel)

WhiteSky

Suresh H12-Jan-07 2:11

Suresh H

12-Jan-07 2:11

Thanks WhiteSky i did the changes its working now.

Thank you very much.

PJ Arends12-Jan-07 9:36

PJ Arends

12-Jan-07 9:36

Suresh H wrote:
How to link shlwapi.lib file to code ???

When you include the header file simply add a pragma to link the lib

#include <shlwapi.h>
#pragma comment(lib, "shlwapi.lib")

Lot easier than mucking around in the project settings and you will never forget it if you reuse the file in another project.

You may be right
I may be crazy
-- Billy Joel --

Within you lies the power for good, use it!!!

Hamid_RT12-Jan-07 1:14

12-Jan-07 1:14

See PathFileExists

WhiteSky

James R. Twine12-Jan-07 1:32

James R. Twine

12-Jan-07 1:32

   IF the directory has to exist regardless of it being there already or your having to create it, just call ::CreateDirectory(...)! If the directory already exists, it will return an error, if it does not, it will attempt to create it.

   No need for all that other crap unless you really need to know if it exists beforehand.

   Peace!