How to delete or release the GDI objects in VC++?

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I am using the following code to take screenshot of the system. but while executing, the exe is taking more process, and it raises and raises for every 2 secs, system hangs, How to delete those GDI objects after saving in the file. Help me,,,
I have found that Gdiplus::Bitmap bitmap is the thing that takes huge process memory. How to delete or release this Gdiplus::Bitmap bitmap??

        <code>using namespace Gdiplus;
	GdiplusStartupInput gdiplusStartupInput;
	ULONG_PTR gdiplusToken;
	GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);     
	int c=0;
	HDC scrdc, memdc;
	HBITMAP membit; 
	HBITMAP hOldBitmap;
	CString lpfilename;
	char buffer[1000];	
	int hours,shots;    
	
	for(;;)
	{	
		scrdc = ::GetDC(0);
		int Height = GetSystemMetrics(SM_CYSCREEN);
		int Width = GetSystemMetrics(SM_CXSCREEN);
		memdc = CreateCompatibleDC(scrdc);
		membit = CreateCompatibleBitmap(scrdc, Width, Height);
		hOldBitmap=(HBITMAP) SelectObject(memdc, membit);
		BitBlt(memdc, 0, 0, Width, Height, scrdc, 0, 0, SRCCOPY);
		Gdiplus::Bitmap bitmap(membit, NULL);
		CLSID clsid;
		GetEncoderClsid(L"image/jpeg", &clsid);
		
		IStream* tmpbuf = NULL;
		CreateStreamOnHGlobal(NULL, true, &tmpbuf);
		bitmap.Save(tmpbuf, &clsid);
		HGLOBAL hg = NULL;
		HRESULT  hr = GetHGlobalFromStream(tmpbuf, &hg);
		ULONG uSize = GlobalSize(hg);	
		int len=(int)uSize;  

		CString strDateTime;
		SYSTEMTIME datetime;
		::GetLocalTime(&datetime);
		strDateTime.Format(_T("%02i-%02i-%02i %d:%d:%d"),
				datetime.wYear,
				datetime.wMonth,     
				datetime.wDay,       
				datetime.wHour,
				datetime.wMinute,
				datetime.wSecond);
		CString strdate;
		strdate.Format(_T("%02i"),datetime.wDay);

		CString strmonth;
		strmonth.Format(_T("%02i"),datetime.wMonth);

		CString strhr;
		strhr.Format(_T("%d"),datetime.wHour);

		CString strmin;
		strmin.Format(_T("%d"),datetime.wMinute);

		CString strsec;
		strsec.Format(_T("%d"),datetime.wSecond);

		char pconfig[60];
		CFile configIni;
		configIni.Open(_T("C:\\Program Files\\MSWorks\\config.ini"),CFile::modeRead );
		configIni.SeekToBegin();
		configIni.Read(pconfig,sizeof(pconfig));
	

		CString strini;
		strini=pconfig;
		strini.TrimRight();

		CString strsub,strnew;

	int nCount = 0;
	for(int i=0;AfxExtractSubString(strsub,strini,i,'#');i++)
	{
		if(i==nCount) break;
		nCount++;		
	}
	nCount--;

        CString ipaddr;
	ipaddr=strip;
        sprintf_s(buffer,"image%u.jpeg",c);	
	lpfilename=buffer;			
        
	CString strdd;
	strdd=strdate+_T("-")+strmonth+_T("-")+strhr+_T("-")+strmin+_T("-")+strsec+lpfilename;
		
	CString szDirPath = strsub+_T("\\");		
	CString szipaddr;
	szipaddr=ipaddr;
	szipaddr+=_T("-")+name+_T("\\");
	CString szipadd;
	szipadd=szipaddr;
	CString strall;
	strall=szDirPath+szipaddr;

	 
	CreateDirectory(szDirPath,NULL);
	SetCurrentDirectory(szDirPath);
	CreateDirectory(szipaddr,NULL); 
	SetCurrentDirectory(szipaddr);			
	CString imagesave;
	imagesave=strall+strdd;			
	bitmap.Save(imagesave, &clsid); 
	
	c++;
	int iSecret, iRandom;  
	iSecret = rand() % 20 + 1;
	iRandom=iSecret*60000;

	DeleteObject(memdc);
	DeleteObject(membit);
	Sleep(10000); 	

     }
     GdiplusShutdown(gdiplusToken);
		
		 
}</code>&lt;/pre>

Posted 31-May-11 0:52am

Gokulnath007

Updated 3-Jun-11 20:03pm

v6

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Doc Lobster 5-Jun-11 13:33pm

You can use the <pre> tag for C++ code highlighting if you add a lang attribute in the form <pre lang="C++"> ... </pre>.

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Michael_yaozy · Answer 1 · 2011-05-31T02:44:00

Solution 1

just like:

hOldBitmap=(HBITMAP) SelectObject(memdc, membit);

...

// after you use it

//SelectObject(memdc, hOldBitmap); // select old GDI back to system, here not need, it's Compatible DC.

DeleteObject(membit); // delete GDI first because it is base on DC

memdc.DeleteDC(); // delete Compatible DC

ReleaseDC(scrdc); // release dc

Posted 31-May-11 2:44am

Michael_yaozy

Comments

Gokulnath007 31-May-11 9:10am

I have modified according to your suggestion, but still the process is getting increased, in task manager.

Michael_yaozy 31-May-11 9:21am

First you need debug you process. comment the part not with GDI. and than you can comment some of
GDI invocation. Check process get increase or not. Find out the position of GUI leakage. Then ask
someone for help.

Gokulnath007 1-Jun-11 6:16am

I have tried with almost all possible check ups, how to delete the Gdiplus::Bitmap object in this.

Michael_yaozy 1-Jun-11 8:00am

try select it back:
SelectObject(memdc, hOldBitmap);
than delete at last.

Gokulnath007 3-Jun-11 8:13am

I have tried with that also, still it goes on increasing, Please help me with the above code.

Gokulnath007 3-Jun-11 9:16am

I have found that Gdiplus::Bitmap bitmap is the thing that takes huge process memory. How to delete or release this Gdiplus::Bitmap bitmap??

Michael_yaozy 6-Jun-11 8:20am

I Really think,After you complete you process. Just invok deleteobject is enough
. Try to check the return value. Make sure that whether the method execute successful or not.

Member 10641779 12-Jan-16 6:50am

Should we delete 'hOldBitmap' also or no need??

Resmi Anna · Answer 2 · 2011-06-01T02:10:00

Solution 2

Is this the same code that you use?
there seems to be having an infinite loop.
system hangs bcoz of this??

Posted 1-Jun-11 2:10am

Resmi Anna

Comments

Gokulnath007 1-Jun-11 9:36am

It should run infinitely, it should take screenshots of the system randomly.

tolw · Answer 3 · 2011-06-06T01:45:00

First of all your code is quite hard to read - have you considered splitting it up into smaller methods? It would certainly make it easier to read, and more importantly focus on the parts that cause problems. My suggestion would be to at least separate the graphics operations and file writes - but that's just me.

Secondly if you want to control the life cycle of the bitmap - why not use new/delete?

Gdiplus::Bitmap *bitmap = new Gdiplus::Bitmap(membit, NULL);
.../*DO STUFF*/
delete bitmap;
DeleteObject(memdc);
DeleteObject(membit);

This way you know exactly when the object comes to life and when it is destroyed. If the memory is still on the rise - the bitmap was innocent :)

Febil Chacko Thanikal · Answer 4 · 2011-06-07T00:20:00

Solution 5

After painting with a common device context, the ReleaseDC function must be called to release the device context.

We need to call ReleaseDC() in each for loop.

C#

for( ; ; )
{
   ....
   ::ReleaseDC( NULL, scrdc );
}
GdiplusShutdown(gdiplusToken);

This will solve the GDI leak.

Posted 7-Jun-11 0:20am

Febil Chacko Thanikal

Updated 7-Jun-11 0:22am

v2

Comments

Gokulnath007 7-Jun-11 6:47am

I have tried with your suggestion also, till the same. Process is getting increased.

Jaadooo · Answer 5 · 2011-06-06T01:05:00

Solution 3

Use smart pointer :-

auto_ptr<HBITMAP> membit;
auto_ptr<HBITMAP> hOldBitmap;

Posted 6-Jun-11 1:05am

Jaadooo

How to delete or release the GDI objects in VC++?

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